Removal of Kerosene from Wastewater: Current Trends and Emerging Perspectives for Environmental Remediation

Abstract

Kerosene spills from industrial processes, oil spills, and improper waste disposal can pose significant risks to human health and the environment due to their toxicity, persistence, and bioaccumulation. This review will provide an integrated overview of kerosene removal from wastewater, drawing on the most recent developments, material design recommendations, scalability concepts, and possible future directions. Conventional treatment processes such as adsorption, membrane separation, advanced oxidation processes (AOPs), and biodegradation are assessed critically in light of performance, scalability, and environmental applicability. The review focuses on the synthesis of novel materials such as nanocomposites, porous materials, functionalized polymers, and bio-inspired materials based on designs of high selectivity, reusability, and improved degradation/separation efficiencies. In addition, some emerging trends are highlighted with the review, including the use of cost–effective and sustainable materials, and the circular economy. Given the substantial knowledge- and problem-gap issues, the goal of this research is to provide pathways for researchers to develop efficient, sustainable, and scalable kerosene–contaminated wastewater treatment technologies to assist with water resourcing and conservation.

1. Introduction

Kerosene is a type of mid-distillate petroleum which is a mixture of aliphatic and aromatic hydrocarbons that have 10 to 16 carbon atoms (C₁₀–C₁₆). It has many uses including aviation fuel, heating, and industrial applications. Kerosene enters wastewater as a result of spills and leaks, cleaning up equipment, runoff from depots and fuel dumps, and improper disposal the fuels from airports, refineries, and other industrial locations. With its poor solubility in water, and the complexity of its chemical structure, and the partial resistance to treatment through biodegradation of kerosene causes serious problems for conventional treatment facilities. Additionally, the presence of kerosene inhibits the activity of microorganisms, produces coatings on the water’s surface that inhibit the transfer of oxygen, and adds toxic components (such as the alkylbenzenes and PAHs) into aquatic environments [1,2,3].

Petroleum hydrocarbons are persistent, bioaccumulative, and extremely debilitating to aquatic life, with long-term environmental impairment [4,5]. Petroleum hydrocarbons lower water dissolved oxygen, inhibit aquatic plant photosynthesis, and harm fish and shellfish gills and reproductive tracts [6]. Hydrocarbon water contamination is not a preference of human beings because it impacts human health negatively by causing neurological damage, cancer, and organ dysfunction [7]. Hydrocarbon contamination also renders water unsafe for human consumption, agriculture, and recreation and hence causes water scarcity and financial loss to contaminated communities [8]. Hydrocarbon toxicity and persistence necessitate the cleanup of water and spills [9,10]. Prevention of petroleum hydrocarbon contamination and clean water availability are of the utmost importance in protecting human health, conservation of nature, and growing demands of sustainable development [11,12].

Kerosene is a petroderivative that has extensive applications as fuel in the aviation industry, domestic use, and industry [13]. It is a global terrestrial and aquatic pollutant on the basis of the fact that it is normally released along with industrial operations and the frequency of spillage accidents [13]. Its general use, accessibility, and storage in bulk involve a high likelihood of accidental release to the environment [14]. Industrial processes such as petrochemical refining, fuel transportation, and storage are frequent causes of kerosene spills and are typically caused by pipeline rupture, equipment failure, or improper disposal technique [15]. Spills resulting from improper handling of fuels during transport, tank explosions, or road accidents; apparently ubiquitous around river or sea courses; are also causative agents behind widespread kerosene contamination of water bodies [16,17]. After discharge, kerosene forms surface films that delay oxygen transfer, hamper aquatic life, and seep into soil and thereby pollute groundwater [18]. Its very intricate hydrocarbon configuration of aliphatic and aromatic hydrocarbons is extremely toxic to water, toxic to plants, and even toxic to people by bioaccumulation and chronic exposure [19,20,21]. Its ability to survive as well as migrate in the surroundings only adds to its impacts, its elimination being a difficult undertaking [21]. Coupled with this is its volatility as well as low biodegradability which causes contamination of water as well as air [22]. In the case of non-controlled environmental conditions, kerosene spillage as well as dumping exacerbates all these issues, posing a danger to ecosystem integrity as well as human health [23,24].

Kerosene classification as a major pollutant requires prevention, spill early warning systems for detection, and proper remediation technologies [25,26]. Kerosene pollution decontamination must be treated with an interdisciplinary approach through regulation compliance, green engineering practices, and public awareness to counteract its effect on the environment [27]. In response to increasing fuel requirements around the globe, the preparation of prevention and rehabilitation measures against the pollution of kerosene is the primary policy to maintain long-term environmental equilibrium and preserve valuable water resources.

Kerosene-water poses both an environmental and health hazard since the chemical constituents are toxic and non-biodegradable [9,14]. The 96 h Lethal Concentration 50% (LC₅₀) for fish is 800 mg/L, while for algae LC₅₀ is 450 mg/L. For the water accommodated fraction (WAF) the regulatory assessment lists typical ranges: fish 96 h Lethal Loading 50% (LL₅₀) Loading rate causing 50% non-lethal effect (EL₅₀) in the range 18–25 mg/L, aquatic invertebrates 48 h EL/EC₅₀ 1.4–21 mg/L, aquatic plants 5–11 mg/L. These lower values refer to highly soluble fraction (a more toxic fraction), not bulk kerosene. Kerosene strips oxygen from water, decreases its volume, and prevents gas exchange by surface films, leading to asphyxiation of aquatic life and fish [6]. Its hydrocarbon composition, e.g., alkanes and aromatics, bioaccumulates in the food chain to lead to species richness and desecration of ecosystems [28]. Land degradation from kerosene pollution and soil and groundwater contamination by spillage or leakage of kerosene also lowers the quality of land, inhibiting vegetation growth and agricultural yield [29]. In human health, exposure of humans to kerosene-polluted water through contact, ingestion, or inhalation of Kerosene vapors may result in a complete set of health problems [14]. These range from skin irritations, respiratory issues, and kidney and liver damage, to even delayed effects like cancer following exposure to chemical carcinogens like benzene [14]. The poor and children bear the brunt since they face the maximum risk due to their exclusion from access to clean water and drugs [14]. The oiliness and foul odor also make the water adulterated with kerosene unpalatable for domestic use, thus exacerbating the water crisis. Prevention of such events necessitates preventive spilling, good cleaning, and increased regulation for the protection of human life as well as the environment.

Assessment of the kerosene removal processes from contaminated water is of prime concern in view of the extensive use of the compound, environmental bioaccumulation, and its harmful ecological and health impacts [30]. Kerosene pollution most often originates from the discharge of industrial effluents, accidental spilling, and reckless dumping, leading to sustained surface water, groundwater, and soil pollution [13]. Because of its recalcitrant hydrocarbon composition, it defies natural weathering, and therefore efficient and eco-friendly remedy methods need to be developed [18]. The traditional removal techniques of skimming, adsorption, and chemical treatment have all been successful to some extent but are predominantly marred by inefficiency, cost, or secondary pollution [31]. Recent years have witnessed advances in environmental material science and engineering, which have given rise to novel treatment technologies such as advanced oxidation processes, hybrid technologies, and nanomaterials, and hybrid technologies possessing potential augmented selectivity, reusability, and environmental pleasantness [32]. However, their sustainability, scalability, and efficacy are always under scrutiny [32]. An extensive survey of recently occurring and ongoing approaches is necessary to evaluate their potential applicability for practice, identify limitations available, and establish areas for future research. Such an analysis can guide future policy design and innovation towards enhanced remediation effectiveness and protection of water resources. Lastly, knowledge and development of kerosene removal technologies are at the heart of advancing water sustainability, environmental protection, and public health.

To generate a systematic literature selection for this review, we needed to include all relevant and current scientific developments from 2005 through 2025 on the subject area covered by this review. To accomplish this goal, we systematically searched and retrieved scientific literature including peer-reviewed journal articles and conference proceedings published mainly within the last 20 years (2005–2025) from multiple major academic databases including Scopus, Web of Science, ScienceDirect, and Pubmed. During these database searches, we searched using keywords such as “kerosene removal,” “oil-contaminated wastewater,” “hydrocarbon remediation,” “adsorption,” “membrane filtration,” “bioremediation,” and “advanced oxidation processes,” as well as combinations of keywords. The majority of studies included in this review were written in the English language and focused primarily on kerosene or its major hydrocarbon constituents (e.g., alkanes, aromatics) in aqueous matrices to support a cohesive theme, resulting from experimental data, mechanistic understanding, scalability measurements, and comparative metrics of performance and/or efficiency. Also, consideration of review articles/analyses were included in the systematic selection for context and to identify gaps in research.

This review article provides a new and comprehensive overview of the new trends and developments in kerosene recovery from wastewater, a relatively less investigated area of research compared to other petroleum pollutants. It combines discussion of strictly traditional processes and novel material design concepts like nanotechnology, bio-inspired material, and hybrid systems. Furthermore, the paper provides new methods, like the combined use of circular economy and machine learning paradigms, for efficient remediation with a sustainability mindset. The new review elaborates a new, multi-angled perspective for treating kerosene contamination in environmental matrices through the combination of basic treatment methods and cutting-edge technologies.

The primary objective of this review article is to provide a systematic and critical analysis of future technologies and new methods of kerosene removal from wastewater, with a special focus on their future scope, limitations, and efficiency. The current review concentrates on categorizing and reporting the conventional processes, such as adsorption, membrane separation, and chemical treatment, as well as on novel trends in material science; namely, nanomaterial synthesis, porous materials, and bioadsorbents, which are recyclable, selective, and environmentally friendly. The second general aim is to explore new approaches, e.g., hybrid systems and advanced oxidation processes, with maximal efficiency and sustainability for kerosene decontamination. The review further seeks to emphasize the importance of design strategies in influencing material transformation to operate under real applications. The article further seeks to highlight areas of knowledge gaps and research issues, such as scalability, cost, and sustainability, towards guiding future research. The goal of this review is to support the development of the next generation of remediation technologies by including technical details and new paradigms, such as the circular economy paradigm and machine learning for process optimization. Ultimately, the paper aspires to be one of the good references for researchers, engineers, and policymakers working on environmental remediation and sustainable water management.

2. Sources and Characteristics of Kerosene in Wastewater

Kerosene, also called paraffin, fuel oil No. 1, or lamp oil, is a clear, yellowish liquid with a distinct smell [33]. This flammable liquid is categorized under the large group of hydrocarbons, either naphthenes, paraffins, or aromatics. These hydrocarbons are made up of (mostly) six to sixteen carbon atoms in various lengths of carbon chains, representing a mixture of aliphatic and aromatic molecules, with aromatic molecules present in slightly less than 4% (by weight) [34,35]. Kerosene has a wide range of domestic purposes for heating, cooking, and lighting lamps in homes that primarily occur in developing countries via wick lamps (or high-pressure lamps) [33]. It has many commercial uses, such as an aviation fuel, a solvent for paints and greases, a lubricant for cutting glass, an oil glazing agent, and is a new effective larvicide for mosquito larvae. It is still commonly used today due to its relatively high flash point (≥38 °C), and is considered less dangerous than gasoline (−40 °C) [36].

Since the middle of the 19th century, kerosene has been a significant home fuel; around half a billion houses worldwide continue to use it or other liquid biofuels [37]. The home sector is thought to account for over 70% of kerosene sales, with the remainder going to commercial, agricultural, and industrial applications. The availability of gaseous fuels and electrification has significantly reduced the home usage of kerosene in developed nations. However, kerosene is still widely used for cooking, heating, and lighting in developing and underdeveloped nations [33]. Kerosene is extremely combustible, just like other petroleum derivatives, and exposure to it can have a number of negative effects [38]. Some of kerosene’s physicochemical characteristics suggest that it may be harmful to both the environment and living things, as

Table 1. Kerosene’s specific physicochemical characteristics and related hazards.

Property	Description/Level	Associated Hazard	References
Viscosity	Surface tension and Low viscosity, density = 0.80 mg/mL	Aspiration/fires/ingestion	[33]
Stability	Generally stable, incompatible materials, ignition sources (flames, sparks), however unstable with heat	Explosion/fire	[14]
Reactivity	Reactive with oxidizing agents	Explosion/fire	[14]
Solubility	Hot water and insoluble in cold, miscible with other petroleum fuels/solvents	Fire/dermal irritation	[14]
Appearance and physical state	yellow or clear in color (light), liquid (oily liquid)	Poisoning/ingestion	[39]
Flash point	≥38 °C	Fire	[40]
Volatility	At 20 °C, 0.48 mmHg (vapor pressure): low volatility	Fire/inhalation	[14]

illustrates.

Exposures to raw fuel, aerosol/vapor, or fuel combustion exhaust can happen either acutely or chronically through oral ingestion, cutaneous or ocular routes, or pulmonary inhalation [33]. Researchers have extensively examined the biological and health effects of exposure to performance additive-based jet fuels and kerosene, even though exposure to air, soil, and fuel-contaminated food, groundwater, and drinking water typically results in low levels of kerosene exposure when they do occur, but they can occur repeatedly and cause harmful effects over time. These exposures often occur concurrently with exposure to other performance additives and chemicals that are commonly added to raw kerosene, such as jet fuels, some of which are known to cause adverse health effects [34].

The residential uses of kerosene, its related risks, and its emissions, particularly in developing nations, were also thoroughly examined by another study group [33]. Kerosene’s hazardous nature and wide range of applications result in a high rate of morbidity and mortality linked to many exposure routes. The kind of kerosene consumption is directly related to the prevalence of exposure-related mortality and morbidity cases. Furthermore, as shown in

Table 2. Common applications and exposure situations for kerosene.

Kerosene Use	Exposure Scenarios	Persons at Risk to Exposure	Reference
Aircraft fuel	Exposure to fuel or aerosol contaminated water or food, respiratory exposure, aerosol and fuel-soaked clothing/dermal contact with fuel	Flight passengers, handling personnel/fuel manufacturing and aircraft maintenance, avionics	[34]
Domestic	Accidental ingestion, respiratory exposure, ocular and dermal	Children and women	[33]
Commercial and industrial	Respiratory exposure and dermal, accidental ingestion	Factory production workers, automobile and other machinery repair personnel, children and farmers, construction workers	[50]

, the exposure scenarios and the afflicted individual type are also connected to the use. For instance, because kerosene is transparent and typically kept in soft drink bottles, it can occasionally be inadvertently consumed in a home setting when mistaken for various soft drink varieties, especially by young children [41,42]. The poor and lower middle class are the high-risk groups most exposed to the risks of kerosene in the same setting because they cannot afford the more costly but cleaner fuel alternatives. Additionally, children under five years old who have experienced accidental poisoning from ingestion are also at risk [43]. Since they prepare the family’s meals, women are even more vulnerable to burns and vapor exposure in this category. As a result, there is a good likelihood that the risks that women face from kerosene exposure will also affect the fetus during pregnancy. It is important to note that the majority of pediatric poisoning cases caused by unintentional kerosene consumption have shown survival after consumption of up to 1.7 g/kg, with fatalities linked to dosages ranging from 2 to 17 g/kg [38,44,45]. However, rather than systemic poisoning from kerosene itself, these deaths or severe instances were primarily linked to aspiration of vomitus and chemical pneumonitis. Although actual dosages consumed were not given due to considerable fluctuation, health professionals have reported occurrences of persistent oral exposure to kerosene in Kenyan school-aged children who are adolescents [46]. There are currently no additional data on chronic oral exposure to kerosene in humans, which may be explained by the fact that such exposure is typically extremely unlikely to occur in normal circumstances. However, doses as high as 200 mL and more than 5 mL have been documented for deliberate ingestion and intravenous injection by suicidal patients, respectively [47,48,49].

This section addresses the numerous negative health effects that kerosene users may experience, as reported in a variety of literature sources, as well as the potential processes by which kerosene may harm different bodily systems and organs. Studies utilizing animal models have provided more information about the harm caused by kerosene than intentional and unintentional human exposures. The results show the wider threat that unregulated exposure to kerosene poses to the environment as a whole, even while such data can be used to deduce the likely harm that kerosene poses to humans. Furthermore, some research has examined the potential harm that plants may suffer from exposure to kerosene [51]. Numerous studies looking into the harmful effects of kerosene on people have placed it in the same category as other dangerous substances. Kerosene was the most frequent cause, accounting for 24% of all cases, according to one study that reviewed the profiles of children with exposures and poisonings who visited a hospital in Cape Town, South Africa, between 2003 and 2008 [52]. During the study period, two kerosene-related deaths were among the 124 poisoning cases that were documented. Even though the number has been steadily declining over time, the researchers concluded that kerosene and pharmaceuticals continue to be the primary causes of pediatric exposures and poisonings in the area. Similar results were obtained from a study carried out in Egypt to determine the incidence rate and contributing factors of acute poisoning in children between the ages of one and sixty months, which revealed that kerosene alone was implicated in 24% of all cases [53].

As previously said, kerosene uses decreases as nations grow, particularly for home uses. Even in developing countries, where ecological fuels are used for heating and lighting, kerosene pollution continues to have a negative impact. In the less industrialized nations, the rates of kerosene-related death and morbidity are significantly greater. This is not meant to highlight the magnitude of kerosene-mediated negative consequences that have been documented in industrialized nations, typically due to industrial applications, aviation fuels, and other unintentional kerosene poisoning cases [47]. Apart from the very frequent instances of kerosene exposure alone, there have also been reports of co-exposure to other chemicals, albeit to a lesser degree. Co-exposure frequently led to enhanced toxicity and was typically linked to reports of suicidal occurrences [49]. In one instance, 200 milliliters of metformin and kerosene were consumed, which led to severe lactic acidosis and abrupt renal failure [49]. The consumption of kerosene combined with chlorinated paraffin, organophosphate, microcrystalline wax, and polyethylene glycol was implicated in other documented suicidal cases [47]. In animals or in vitro, co-exposure to kerosene fuel or soot with benzo–pyrene or chrysotile asbestos led to enhanced toxicity, namely adverse effects on the skin barrier, altered lung metabolic processes, and genotoxicity, just like in people [54,55]. Relatively speaking, kerosene may be a greater hazard to humans and other living things than other compounds in the same category, according to studies conducted on plants, people, and animals, some of which are covered above. A contributing factor in the ongoing disregard for the harm kerosene does to the populace is the dearth of important information regarding its detrimental health effects. Nonetheless, a sufficient understanding will make it easier to create pertinent policies and focused programs for the management and prevention of kerosene-mediated morbidity and death.

Negative Health Effects of Kerosene and Potential Toxicological Mechanisms

Exposure to unburned crude kerosene may result in kerosene-mediated adverse health consequences, which are mostly caused by the fuel’s chemical components, any added fuel performance additives, or the exhaust fumes from burning it. Unfortunately, no conclusive distribution, absorption, excretion, and metabolism data are available because kerosene is a mixture of chemicals from multiple classes, including branched alkanes, diaromatics, n-alkanes, alkylmonoaromatics, naphthalenes, monoaromatics, and polynuclear aromatics, occurring in varying proportions [47]. Because metabolites originating from a single primary chemical component also differ structurally, it has been challenging to determine which ones are most dangerous. Except for fuel performance additives,

Table 3. Negative health effects caused by specific kerosene chemical components.

Chemical Component	Examples of Possible Bioactive Metabolites	Adverse Health Effects	Reference
Benzene	1,2,4-trihydrozybenzene, 1,4-benzoquinone, tt-muconaldehyde, cathecol and hydroquinone	Neurotoxicity, hematopoietic disorders especially nonlymphoblastic leukemia and aplastic anemia	[34]
n-Hexane	2-hexanone, 1-hexanol, 2-hexanol- and 3-hexanol	Neurotoxicity, carcinomas and hepatocellular adenomas, reduced postnatal growth, lung damage, intestinal irritation and severe bronchial	[34]
Naphthalene	1,4-napthoquinone and 1,2-napthalene oxide	Cataracts, renal and pulmonary toxicity	[14]
Polycyclic aromatic hydrocarbons	Dihydrodiol epoxide, (8S, 7R)-dihydroxy-(10R, 9S)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene	Mutagenicity and carcinogenicity	[47]

summarizes the harmful health consequences caused by the individual chemical components in kerosene during exposure and offers instances of their potential bioactive metabolites. According to scant information from metabolism research, the liver and lungs filter kerosene out of the bloodstream [38].

The health implications of exposure to individual combustion exhaust emissions from kerosene and fuel performance additives have been covered in great detail by other authors [33,56,57,58]. The additives and individual chemical components of kerosene may be directly responsible for some of its harmful health consequences, but it is more likely that these elements and additives will work in concert to cause or worsen these effects. Accordingly, this part addresses the harmful health effects of kerosene as a combined chemical, which are summed up in Figure 1 and

Table 4. Deleterious effects of kerosene in experimental animals that are related to both the system and the dose.

Body System/Organ	Animal Model/Exposure Route	Dose Level/Duration	Symptoms	Reference
Endocrine	Rat/dietary	10–300 μL/day/28 days	Aggression and increased testosterone	[46]
Endocrine	Wistar male rats/subcutaneous	0.5 mL/kg/6 days	Adrenal lesions	[59]
Cardiovascular	Canine/aspiration	0.5 mL/kg/4 h	Blood pressure decreased and heart rate	[60]
Cardiovascular	Guinea pigs/aerosol	34 g/m3/15 min/day	Increased cholesterol and decreased high density lipoprotein, aortic plaques	[61]
Hematological and immune	Mice/aerosol	1000 mg/m3/1 h/day for 7 days	Thymic weights and decreased splenic, immunosuppression	[62]
Hematological and immune	Rat/dietary	10–300 μL/day/28 days	Increased white blood cells, red blood cells, platelets, hematocrit concentration, red cell distribution width, hemoglobin and corpuscular volumes	[46]
Pulmonary	Goats/intratracheal	40 mL/kg/4 h	Pleuropneumonia and fatal gangrenous pneumonia	[63]
Liver	Wistar male rats/subcutaneous	0.5 mL/kg/6 days/week	Carboxylesterase levels, cholinesterase, albumin, decreased benzo[a]pyrene hydroxylase, increased alkaline phosphatase, increased liver weights and presence of lesions	[59]
Gastrointestinal	Rat/dietary	10–300 μL/day/28 days	Chronic gastritis	[46]
Pulmonary	Canine/aspiration	0.5 mL/kg/4 h	Hypoxaemia, intrapulmonary physiologic shunting	[60]
Pulmonary	Guinea pigs/aerosol	34 g/m3/15 min/day	Pulmonary pathology	[61]
Carcinogenicity/genotoxicity	Rat/stomach tube	500–800 mg/kg/day/104 weeks	Increase in the total number malignant tumors and of some site-specific tumours, intermediate to sharp reduction in survival	[64]
Skin	Mice/topical	25 m μL/1–72 h	Ability of the skin to retain water compromised dermal barrier function	[54]
Skin	Dawley rats-sprague/topical on shaved backs	495, 330 or 165 mg/kg/day/7–8 weeks	Slight to moderate skin irritation, at the highest dose	[65]

, as well as the potential toxicity processes in the bodily systems, tissues, or organs that are impacted.

Regular exposure to home cooking fuels has been found by researchers to be a significant source of indoor air pollution, which impairs lung function and is a major cause of death and morbidity [66]. This can be linked to the release of harmful vapors into the atmosphere that cause tissue inflammation and oxidative stress. These vapors include small fine particles and polyaromatics, nitric oxides, sulfur dioxide, carbon monoxide, and formaldehyde [33]. Strong and consistent evidence indicates that burning kerosene releases particulate matter with a mean aerodynamic diameter far below 2.5 μm, much of which lodges deep in the lungs and raises the risk of respiratory illnesses [33,67]. The size distributions of CO₂, CO, nitrous oxides, and particulate matter, as well as their concentrations, and kerosene lamps were recently studied in Nigeria and Kenya. The results showed that all single-wick lamp burn rates (with only one single-wick lamp) exceeded the WHO’s 24 h PM2.5 concentration guideline by at least 1 [68]. When multiple lamps were used, the fuel-burning lamp’s overall intake contribution increased. It was discovered that the cheapest and most basic kerosene lamps released the most PM2.5. Although it has been demonstrated that using hurricane lights reduces exposure to PM2.5 and particles with concentrations below 10 μm, many rural areas may not be able to afford them. In addition to kerosene lamps, the literature has examined PM concentrations from several kerosene stove types. Overall, both studies show that the levels of PM10, PM2.5, NO₂, CO, and SO₂ in kitchen air are well below permissible limits [69]. When combined, these results demonstrate that small residential and commercial indoor spaces in the developing world have significant levels of PM pollution that have an impact on respiratory health. Additional research findings show that extended exposure to cooking fuels has a detrimental impact on peak expiratory flow rate [66]. Separate case–control studies that examined the connection between indoor biomass and tuberculosis were carried out in India and Nepal. These studies found evidence of a link between tuberculosis and exposure to smoke from kerosene combustion, whether in stoves or lamps [70,71]. Remarkably, comparable research carried out in southern Ethiopia revealed no proof linking the usage of biomass fuel to tuberculosis [72]. The authors attributed these unfavorable results to inadequate statistical power brought on by the choice of neighborhood controls. Even if the two studies carried out in India and Nepal offer compelling data, more research could be required to validate the connection between kerosene exposure and tuberculosis. In general, research on the harmful effects of kerosene on the pulmonary system in animal models and documented human cases is consistent. An overview of the research performed on animals and the negative consequences of kerosene exposure is given in Table 4.

The second most common cause of kerosene exposure-related morbidity and death is neurotoxicity. Due to their line of work, serval groups of persons are exposed to vapors, combustion gases, or aerosols from kerosene and certain hydrocarbon fuels. Military troops, airline workers, house cooks, and gas station attendants are a few examples. It is well recognized that exposure to these hydrocarbon fuels can have neurological effects [34]. Additionally, there is the problem of neurotoxicity when up to six performance additives are added to current fuel compositions. The route of kerosene exposure may also affect the likelihood of neurotoxic consequences. For instance, cutaneous exposure is extremely unlikely to cause neurotoxicity, but direct ingestion and inhalation are more likely to do so [73]. When hydrodesulfurized kerosene was administered to the shaved backs of Sprague-Dawley CD rats as part of a study to examine neurotoxicity and target organ toxicity, no neurotoxic effects were found [65]. However, the greatest degree of ambiguity in this study stems from the distinctions between human and rodent skin. However, direct intake and inhalation cause a variety of clinical symptoms, such as involvement of the central nervous system [74]. One-third of kerosene poisoning patients in a six-year prospective study at a teaching hospital in Jordan displayed symptoms of central nervous system damage, such as lethargy, convulsions, stupor, death, and coma [34,75]. Although central nervous system toxicity can still happen without concurrent pulmonary, hypoxic, or other disease, symptoms of central nervous system involvement have been demonstrated to correlate with fever, hypoxemia, and pneumonia. One possible explanation for the effects of hypoxia on the central nervous system is the inhibition of acetylcholinesterase in the guinea pig trachea, which results in a significant increase in smooth muscle activity in the airways [14]. According to research using synaptosomal membranes from the central nervous systems of rats exposed to kerosene (in vitro), organic solvents decreased the activity of the enzyme (Mg²⁺/Ca²⁺) adenosine triphosphatase, which in turn increased intracellular Ca²⁺ levels and neurotransmitter release. This suggests another possible mechanism for hypoxia-induced neurotoxicity [76,77,78,79]. Animal research on kerosene-induced neurotoxicity is still insufficient and often inconclusive [73]. Nonetheless, as Table 3 summarizes, there are a number of studies that focus on the specific chemical components of kerosene and their ability to cause neurotoxicity [34].

Recent research employing in vitro and in vivo mouse models has demonstrated that kerosene treatment increased the absorption of carcinogens and impaired the skin’s dermal barrier function and water retention [54]. This suggests that kerosene pouring onto skin surfaces compromises the skin’s defenses against potentially dangerous foreign chemicals, including bacteria and carcinogenic polycyclic aromatic compounds. Human epidermal keratinocytes exposed to JP-8, a commercial kerosene-based aircraft fuel used by the US military, have demonstrated in vitro assays that JP-8 had the most detrimental effect on inflammation and cell viability when compared to other fuels (such as synthetic fuel S-8) [80]. According to other research, kerosene causes skin lesions, dermatitis, and cutaneous sensitivity and irritation [65,81,82]. A significant frequency of oil acne and dermatitis of various degrees was observed in 24 human volunteers who were exposed to kerosene on a regular basis in an automotive workshop. These findings highlight the need for vigilance whenever continuous cutaneous exposure to kerosene occurs in an occupational setting [82]. The removal of endogenous lipids from the skin may be the cause of dermatitis, whereas oxidative stress and elevated pro-inflammatory cytokines encourage dermal inflammation [34]. Burns that cause varied degrees of skin damage are directly caused by kerosene, even though they are not the consequence of direct touch [40]. When exposed to heat, an open flame, a spark, or another ignition source (such as lighted cigarettes), kerosene vapor can readily catch fire. Because of this, using it necessitates following safety regulations when storing it. Since kerosene reacts with strong oxidizers like nitric and nitric acids, keeping it away from them is another crucial and secure storage precaution [47].

To handle the high volume of patients hospitalized with varying degrees of burns, many large hospitals maintain a specialized burn unit. While there are many different causes of these burns, some are rather common. Kerosene is one of the main candidates to be the primary cause of burns, according to numerous studies. In a retrospective analysis conducted between 2001 and 2010, a database from the burn unit of a hospital in India was analyzed. The scientists came to the conclusion that, out of 2.499 burn patients, 80% were caused by flames, 96% occurred in the home, and 29% occurred in traditional Indian stoves. The most frequent causes were hot liquids (12%), kerosene lamps (27%), and stoves (10%). Kerosene was implicated in at least 37% of all instances overall [83]. One study at a national hospital in Kenya indicated that the wick-type kerosene stove was the most likely to explode [14]. Most of the time, the primary cause of burns caused by kerosene was ignorance of proper safety measures and safeguards. The usage of dangerous appliances, such as kerosene stoves and heaters in dangerous areas like bathrooms and kitchens, was one of the most frequent causes of fatal burns, according to a study that used the Haddon Matrix to investigate potential reasons [14]. Kerosene is a substance that releases vapors that readily combine to form flammable combinations; if these vapors build up, they have the potential to ignite or explode. Additionally, kerosene can accumulate static charges that could result in an electrical fire. Kerosene vapor can move along the ground and reach distant ignition sources since it is combustible and heavier than air, which increases the risk of a flashback fire [36,84,85]. This implies that in addition to kerosene-related fires that are started on purpose and handled dangerously, like refueling stoves that have already been lit with kerosene, many unintentional fires can arise from incorrect kerosene handling and storage, which can cause burns that cause harm or even death [33,86,87].

Histopathological analysis of the liver and other organs showed abnormalities associated with therapy, and the subcutaneous toxicity of kerosene in albino rats was also examined [59]. Alkaline phosphatase levels increased while benzo[a]pyrene hydroxylase levels decreased, according to biochemical indices used to evaluate liver toxicity. Conversely, there was a considerable drop in the levels of albumin, cholinesterase, and carboxylesterase in the serum. Additionally, kerosene hydrocarbons were found to suppress kidney and liver tissue respiration in vitro and to hinder the biotransformation of phenacetin and hexobarbital in vivo in experiments assessing their effects on tissue metabolism in rats [88]. In addition, there was a decrease in blood glucose levels, an increase in lactate and pyruvate concentrations in blood and liver tissue, a decrease in the amount of glycogen in the liver and skeletal muscle, and an increase in the activity of the enzyme lactate dehydrogenase in the liver. Rats with acute poisoning showed these symptoms, but rats with subchronic poisoning showed less noticeable effects. Another study found a similar pattern, which was explained by a potential adaptive mechanism that may activate with time and extended exposure [46]. In contrast to other cell lines that represented the tissue types under study, researchers demonstrated that the H4IIE liver cell line demonstrated reduced toxicity and increased tolerance to JP8 [89]. It was suggested that the decreased hepatic toxicity resulted from the induction of phase I and II detoxifying enzyme expression in liver cells. When an activated aryl hydrocarbon receptor is present, polycyclic aromatic hydrocarbons increase the protective effects on the liver by inducing the production of many detoxification enzymes. In a later investigation, DNA damage was also noted in the same liver cell line exposed to JP8, however this damage was mitigated by DNA repair rather than resulting in apoptosis or cytotoxicity [90].

There are very few published research on the renal damage caused by kerosene in humans. In one of the rare documented instances, a patient who had consumed the liquid contents of lava light which included kerosene, microcrystalline wax, polyethylene glycol, and chlorinated paraffin presented to the emergency room with several symptoms, including acute renal failure [91,92]. However, as kerosene was only one of the ingredients in the cocktail, its involvement is uncertain. But according to a report of another case that directly linked kerosene to metformin, it can interact with the medication, confirming its enhanced toxicity and leading to lactic acidosis and severe renal failure [49]. These harmful effects were thought to result from kerosene-induced renal tubular necrosis and liver and kidney cellular respiration suppression, which causes lactic acid to build up in the blood [88]. Research conducted on animal models has revealed some mild nephropathy linked to kerosene exposure, albeit it is challenging to extrapolate these findings to humans [81,93]. The immune system appears to be more vulnerable to JP-8-induced harm than other bodily systems, as evidenced by immunotoxicity occurring before any harmful consequences in any other system [62]. Experts discovered that JP-8 exposure virtually eliminated splenic natural killer cell function, decreased the burden on immune system organs, dramatically inhibited the production of lymphokine-activated killer cell activity, inhibited immune functions, and decreased the quantity of viable immune cells. Accordingly, a study of JP-8 applied to the skin of adult female HeN/C₃H mice revealed that the induction of contact hypersensitivity was hindered in a dose-dependent manner. Additionally, the serum of mice treated with JP-8 contained interleukin-10, indicating that the mechanism of systemic immunosuppression might involve JP-8’s upregulation of cytokine release [94,95,96].

There have been reports of chromosomal abnormalities and micronuclei in human bone marrow cells and lymphocytes exposed to petroleum fumes [97]. In a different study, blood lymphocytes from populations exposed to burning biomass-based fuels, such as kerosene, showed chromosomal alterations [98,99].

Notably, intermediate distillate fuels have been shown to have tumorigenic activity due to prolonged irritation caused by non-genotoxic mechanisms [50]. Strong promoting drugs that activate protein kinase C and bind to and seem to directly encourage prolonged epidermal hyperplasia without causing significant skin damage may have mechanisms similar to these tumorigenic actions. The other potential process is comparable to that of chemicals that cause significant skin damage, either directly by caustic action or through cumulative irritation [14]. With recurrent episodes of injury and regeneration, these changes result in noticeable epidermal hyperplasia. Oncogene activation is most likely the cause of tumor induction by both pathways, and oxidative enzymes of inflammatory cells may play a role in the activation process. Indeed, research has shown a connection between potential dermal cancer and severe, persistent skin irritation brought on by necrosis, burning, and regeneration [34]. The majority of the data that is currently accessible pertains to solid biomass fuels, particularly wood, even though kerosene is a biomass fuel. It would be instructive to conduct more research explicitly examining the carcinogenic consequences of PM from burning kerosene. Nevertheless, research has been done to determine whether kerosene’s combustion products or specific ingredients are carcinogenic; in this instance, benzene has been identified as a human carcinogen that raises the risk of non-lymphocytic leukemia. Acute myeloid leukemia and non-lymphoblastic leukemia have also been linked in other studies to recurrent exposure to other benzene-containing substances [100]. Immunosuppression brought on by kerosene-based fuels leaves afflicted people more vulnerable to viral infections, which may contribute to the emergence of some cancers [101]. Specifically, kerosene’s polycyclic aromatic molecules have been shown to promote immunosuppression [14]. Lastly, research done on both humans and animals to assess how kerosene affects development and reproduction processes showed that it had no discernible impact [38]. But according to research, there is a strong correlation between astrocytomas in children whose mothers were exposed to kerosene when they were pregnant [102]. Compared to control rats, animals given oral JP-8 gained substantially less body weight during pregnancy, and a significant decrease in fetal body weight suggested embryonic damage [103]. Experts claim that because kerosene-based fuels are linked to decreased NK cell function, female rodents may have less placentation during pregnancy and so have a lower capability for reproduction [104]. Male rats have been shown to suffer from spermatid damage, decreased testicular weight, and testicular shrinkage as a result of ethylene glycol monomethyl ether (an antifreeze component) found in kerosene-based jet fuels [105].

3. Conventional Treatment Techniques

Investigating cutting-edge technology for the treatment of petroleum effluent and its derivatives, including kerosene, is essential given the significant threats to the environment and human health. In order to treat wastewater that contains kerosene, efforts are being made to develop and deploy modern technologies, including chemical, biological, and physicochemical processes [106,107]. These methods seek to satisfy legal criteria while effectively degrading or eliminating contaminants such as oil, kerosene, heavy metals, and organic substances. The environmental impact of petroleum and wastewater created from it can be reduced, hence minimizing dangers to human health and ecosystems. To effectively separate contaminants from water, physical methods mainly use the physical characteristics of the pollutants (such as their density and hydrophilicity). Adsorption, gas lift, and gravity separation are a few examples [1]. To treat petroleum and wastewater resulting from petroleum, chemical procedures such as flocculation, coagulation, precipitation, chemical oxidation, and electrochemical treatment are also employed. Through chemical processes seek to eliminate or change pollutants so they may be separated from water [108,109]. The efficiency of biological treatments in lowering chemical oxygen demand, metal ions, nutrients, and residual organic contaminants has led to their widespread adoption. The biological treatment of petroleum effluent has been facilitated by the use of processes including biological reactors, membrane bioreactors, and biological contact oxidation tanks [110]. Depending on the kind and quantity of contaminants, effective remediation typically combines secondary, primary, and tertiary treatment sequences. Each treatment method has pros and cons of its own. Superior efficacy in eliminating contaminants from wastewater is made possible by the integration of many treatment procedures.

3.1. Primary Treatment

By enhancing the quality of the water entering later treatment units, pretreatment contributes significantly to sewage purification and raises the overall efficacy of sewage treatment procedures. In order to remove settleable and floating debris, suspended particles, oil, and turbidity during the initial treatment phase, pretreatment for oily wastewater frequently uses gravity separation techniques such as precipitation/sedimentation and air flotation [111]. In oily wastewater, API separators are frequently used to remove free oil at concentrations more than 500 mg/L. However, to efficiently remove emulsified oil, dissolved oil, suspended particles, and tiny oil droplets from wastewater, technologies like Induced Air Flotation and Dissolved Air Flotation are utilized [112,113]. The early processing of wastewater containing kerosene can greatly improve the overall effectiveness and performance of sewage treatment systems by utilizing pretreatment techniques including air flotation and gravity separation, which will ultimately result in better water quality outcomes.

3.2. Secondary Treatment

3.2.1. Flocculation/Coagulation

One of the most effective and well-established methods for eliminating a floating oil, suspended solid particles, metals, and dissolved organic compounds from wastewater tainted with kerosene and petroleum products is flocculation/coagulation technology [114]. The colloidal particles become destabilized and form tiny aggregates when flocculants or coagulants are added. The suspended particles then agglomerate or form flocs under the effect of flocculants, which speeds up particle coalescence and achieves liquid-solid separation. The mechanisms fall into three categories: sweep coagulation, interparticle bridging, and charge neutralization [115]. Process variables such as pH, flocculant/coagulant dosage, temperature, beginning concentration, and the type of flocculant/coagulant employed all have a significant impact on how well it treats [116]. Three primary categories can be distinguished from the chemical makeup of commonly used flocculants and coagulants: inorganic salt coagulants, such as aluminum and iron salts; natural polymer flocculants; and synthetic organic flocculants, such as polyacrylic acid, polyacrylamide, and their derivatives [117]. Natural organic flocculants like chitosan, starch, cellulose, and lignin are more readily sourced from renewable resources than conventional flocculants [118]. They have qualities like low cost, biodegradability, and great efficiency. It is crucial to take into account the possible drawbacks even if the flocculation-coagulation process effectively reduces significant amounts of suspended particles and the ensuing organic load in biological treatment processes. Large amounts of harmful sludge and higher expenses can arise from the extensive usage of flocculants and coagulants. To reduce any possible negative effects on the environment, the created sludge must be carefully managed and disposed.

3.2.2. Biological Treatment

The kerosene wastewaters are commonly treated using microbial remediation technologies, which are both economical and environmentally benign. Hydrocarbons are used by bacteria, fungi, and yeasts for development and metabolism; through respiration, they are transformed into carbon dioxide and water [119]. Effectiveness is significantly impacted by variables like salinity, temperature, hydrocarbon type, acidity, and oxygen levels. Most microorganisms break down hydrocarbons in an aerobic manner; through processes like subterminal oxidation, terminal oxidation, β-oxidation, and ω-oxidation, enzymes oxidize hydrocarbons produce carbon dioxide and water [120]. Technologies for bioremediation include composting, bioventing, bioreactors, bioaugmentation, and biostimulation. Enhancement of microbial hydrocarbon elimination through genetic engineering increases the efficiency of oxidative metabolism by focusing on favorable degradation pathways or enzymes in all species [121]. By use of microorganisms’ metabolic processes, colloids and organic contaminants found in wastewater are converted into stable and innocuous compounds [122]. The two growth methods of the microorganisms used in the biological treatment are attached growth and suspended growth. Microorganisms are allowed to float in the water during suspended growth phases. Common suspended growth methods used in wastewater treatment include the membrane bioreactor, the activated sludge process, and the sequencing batch reactor. These procedures give microorganisms the right conditions to break down organic materials and eliminate contaminants [123]. However, in attached growth processes, bacteria create a biofilm on the surface of a solid medium or packaging material as well as inside its pores. Biochar, activated carbon, and polyvinyl chloride are a few examples of packaging materials. Petroleum wastewater encounters the microbial film as it passes through this medium, which promotes the breakdown of organic contaminants. Rotating biological contactors, percolator filters, and fluidized bed bioreactors are common techniques for encouraging attached growth. Depending on the particular wastewater treatment needs, both attached growth and suspended growth techniques are used. A number of variables, including intended treatment efficiency, available space, effluent properties, and operational considerations, influence the choice of biological treatment method.

Microalgae are utilized to break down kerosene spills and are regarded as one of the most promising feedstocks for the manufacture of biofuel. Certain microalgae can create enzymes that degrade hazardous organic molecules and convert petroleum hydrocarbons into less harmful compounds [124]. The researchers have observed that different strains of microalgae have eliminated pyrene, naphthalene, Benzo[a]pyrene, phenanthrene, anthracene, and other polycyclic aromatic hydrocarbons [124]. At 5% kerosene, C. variegata and Chlorella vulgaris grow very slowly; do not grow at 10% kerosene, and die within 10 and 15 days at 20% and 10% kerosene, respectively [125]. In synthetic kerosene wastewater, Anabaena variabilis, Chlorella vulgaris, Desmodesmus, and Neochloris vigensis yielded lipid contents of 37.8, 34.28, 50, and 19.29%, respectively [126]. The ability of green algae Synechococcus sp. and Chlorella vulgaris, together, to break down and grow hydrocarbons like kerosene at varying concentrations (0%, 0.5%, 1%, and 1.5%) was investigated [127]. Dry weight, optical density at 600 nm, and pigment concentration, such as carotenoid chlorophyll, were used to determine the growth of the algae. Using Fourier Transform Infrared Spectroscopy, the rate of kerosene degradation was calculated both before and after the algae and their consortia were cultivated. Using mass spectrometry in conjunction with gas chromatography, the constituents of the methanolic extract were identified. The findings show that the algae consortium with 1.5% kerosene and optical density grew the best after 10 days, whereas the algae consortium with 79.5% dry weight and Synechococcus with 82% also showed moderate levels of fatty acid methyl ester. Kerosene can be eliminated from the medium by the collaboration of the mixotrophic C. vulgaris and the cyanobacterium Synechococcus. The species C. vulgaris that was grown in a mixotrophic environment had the highest dry weight and fat content (Figure 2). Undecane was the most abundant component found in the methanolic extract of the Synechococcus and C. vulgaris consortium. The most distant component in the C. vulgaris methanolic extract was octamethyl, cyclotetrasiloxane. Alkene has the ability to be absorbed and totally extracted from the surrounding medium in the species C. vulgaris, Synechococcus, and its consortium. Thus, a consortium grown with algae in a mixotrophic environment might be used as a raw material to make biofuel [127].

3.3. Tertiary Treatment

In wastewater treatment plants, tertiary treatment also referred to as deep treatment is essential because it eliminates any remaining organic compounds following secondary treatment. This step is necessary to guarantee adherence to water reuse and discharge guidelines established by agencies like the World Health Organization [128]. Wastewater usually satisfies initial discharge requirements following secondary treatment. However, further treatment is needed to meet the problem of quickly eliminating heavy metals (trace quantities) and low-biodegradable organic molecules (such phenols, benzene, ethyl-benzene, toluene and xylenes, phenols, and polycyclic aromatic hydrocarbons) from petroleum effluent. For this reason, typical tertiary treatment techniques have been used, such as sand filtration, activated carbon adsorption, and chemical oxidation with chemicals like hydrogen peroxide and chlorination. Notwithstanding the efficacy of these traditional techniques, the treatment process is severely hampered by the presence of refractory organic molecules in petroleum effluent. Therefore, to find economical and ecologically acceptable solutions for the treatment of petroleum effluent and its derivatives, including kerosene, ongoing innovation in research and development is crucial. The goal of these technologies is to meet environmental discharge standards’ minimum chemicals content requirements. Wastewater treatment facilities can improve the effectiveness of tertiary treatment of kerosene and wastewater derived from petroleum by investigating novel treatment strategies like membrane filtration, sophisticated oxidation procedures, and creative adsorption techniques. These developments support sustainable environmental practices and long-term resource management in addition to improving treatment results.

3.4. Cutting-Edge Technology for Treating Wastewater Contaminated by Kerosene

Recent studies have shown an increasing interest in advanced kerosene wastewater treatment methods. This pattern shows how novel approaches to eliminating particular contaminants from kerosene effluent are becoming more and more popular and innovative. A move toward more effective and advanced treatment methods that seek to address the difficulties involved in eliminating contaminants from petroleum wastewater and its byproducts, such as kerosene, is reflected in the emphasis on membrane technology, adsorption technology, and advanced oxidation processes. Compared to conventional techniques, these cutting-edge technologies have the potential to improve treatment effectiveness, remove more pollutants, and have a smaller environmental impact. Research in this field has the potential to help create more sustainable and efficient methods of treating petroleum wastewater, which would ultimately aid in the management of water resources and environmental preservation initiatives [129].

3.4.1. Adsorption

To recover or remove sewage pollutants and purify the sewage, Patterson first proposed the adsorption method in 1985 as a new technology for treating oily wastewater. This method uses porous solids as adsorbents that interact with the pollutants through chemical (covalent) or physical (non-covalent) interaction mechanisms [130]. Adsorption has a number of benefits over alternative wastewater treatment methods, including affordability, simplicity of use, and non-toxicity to the environment. The use of carbon-based adsorbents in environmental remediation techniques has gained popularity in recent years because of their affordability and ease of use. Numerous carbon compounds have been thoroughly investigated as possible adsorbents for wastewater treatment, including graphene, activated carbon, carbon nanotubes, charcoal, soot, fullerenes, and other derivatives [129,131]. These carbon–based adsorbents have good adsorption qualities and promise to remove contaminants from wastewater efficiently. Furthermore, the practical treatment of petroleum effluents is attracting interest in natural and mineral cellulosic materials [132,133]. These substances provide environmentally friendly substitutes for adsorption procedures in wastewater treatment applications because of their accessibility and affordability. Researchers and professionals can investigate safe and efficient ways to handle petroleum and petroleum-derived effluents and to lessen their environmental impact by employing natural and carbon–based materials as adsorbents [134,135,136]. Two extensively studied adsorbents that are well-known for their efficient pollutant removal properties are biochar and activated carbon. Because of its proven adsorption capabilities, activated carbon is a common industrial adsorbent used to clean exhaust gases and effluents [137]. Many naturally occurring carbonaceous materials, such as plants (fruit seeds, wood, and coconut shells, for example) [138], minerals (peat, lignite, petroleum coke, etc.), and polymers (plastics, rubber tires, etc.) [139], can be used as raw materials to make activated carbon and biochar. These materials are great options for adsorbing both organic and inorganic contaminants because of their many holes, high specific surface areas, low environmental toxicity, and changeable surface groups [140]. Both surface adsorption and osmotic absorption are ways that oils (kerosene) interact with adsorbents. Capillary action pulls oil molecules into the pores after they diffuse onto the surface of the adsorbent’s porous structure during surface adsorption. Porous carbon materials can remove oil by a variety of processes, including pore filling, hydrophobic interactions, hydrogen bonding aided by functional groups like –OH and –COOH, electrostatic attraction, electrophilic interactions, and π-π electron acceptor-donor interactions [141].

One important element affecting the adsorption efficiency is the pore structure of adsorbents. More sites for adsorption are available when the adsorbent’s specific surface area is increased by an extensive pore structure. Research employing activated carbon generated from wood biomass highlights how crucial pore size distribution and structure are in affecting contaminant adsorption [142]. Researchers also examined the usage of biochar to treat oil spills, pointing out the significance of production processes and biomass feedstock for biochar’s adsorption capacity [141]. Researchers analyzed the textural and chemical properties of rice husk activated carbon to determine its capacity to adsorb refractory sulfur compounds of dibenzothiophenes from commercial kerosene [18]. Despite having a significantly lower specific surface area of 473 m²/g and a total pore volume of 0.267 cm³/g than microporous activated carbon fiber, which has a large specific surface area of 2336 m²/g/and a total pore volume of 1052 cm³/g, rice husk activated at 850 °C for 60 min demonstrated an acceptable adsorption capacity for refractory dibenzothiophene sulfur compounds. The adsorption capacity of rice husk activated carbon’s refractory dibenzothiophene sulfur compounds was directly correlated with the volumes of ultramicropores serving as adsorption sites for these compounds and mesopores carrying them into the ultramicropores [18]. Researchers used commercially available activated carbon and powdered jujube and barberry stems to conduct isothermal and kinetic investigations on the adsorption of gasoline and kerosene [143]. Additionally, barberry stem powder, jujube stem powder, and granular activated carbon were able to remove kerosene with removal rates of over 84%, 68%, and 99%, and gasoline with removal rates of over 55%, 69%, and 95.5%, respectively. The Temkin model (R² = 0.95), which was found to best describe the characteristics of barberry stem powder in the adsorption of kerosene and gasoline from wastewater, best illustrates the multilayer adsorption process on a heterogeneous surface that occurs on the jujube adsorbent. Additionally, the Langmuir (R² = 0.73) and Freundlich (R² = 0.74) isotherms were the most effective models for characterizing the properties of granular activated carbon in the adsorption of gasoline and kerosene from water, respectively. With R² > 0.74, the adsorption kinetics demonstrated that the pseudo-second order was suitable for simulating the adsorption kinetics of gasoline and kerosene onto the investigated adsorbents [143]. The removal effectiveness of the adsorbents at different beginning concentrations of the contaminants is briefly described in

Table 5. The effectiveness of the adsorbents to removal, at different initial pollutant concentrations [143].

Adsorbent	Removal Percentage: Kerosene/Gasoline with 1% Initial Concentration	Removal Percentage: Kerosene/Gasoline with 2% Initial Concentration
Jujube tree stem powder	68.48/69.35	43.63/56.57
Barberry tree stem powder	83.87/55	51.8/44.6
Granular activated carbon	99/95.6	65.5/59.5

. The adsorptive behavior of an adsorbate on the surface of a solid occurs linearly until saturation and then finds equilibrium, forming a plateau-shaped curve, which is compatible with nonlinear adjustments of kinetic and isothermal models. It is important to note that all statistical adjustments were carried out in a linear manner, which can provide a removal value extrapolated to the real one [144,145].

A key factor in establishing the physical and chemical characteristics of biochar is the pyrolysis temperature [146]. In contrast to biochar made at lower temperatures, rice husk pyrolyzed at temperatures higher than 350 °C forms a porous structure that increases its ability to absorb oil [147]. But overly high pyrolysis temperatures, like 700 °C, can cause surface oxygen–containing groups to break down, which lowers the effectiveness of oil absorption. The capacity of an adsorbent is influenced by surface chemistry and morphology and is largely determined by lipophilicity and hydrophobicity [148]. Increasing hydrophobicity and lipophilicity through surface modification is a useful tactic for improving adsorption capability. By successfully modifying materials like activated carbon with polymers using techniques like impregnation, researchers have significantly increased the capacity of these materials to adsorb oil [149]. The addition of polyaromatic carbons to biochar adsorbents, which have aromatic structures, improves oil absorption by increasing their hydrophobicity and lipophilicity. To further improve oil absorption capacity, other methods have been used, such as applying superhydrophobic coatings to the surfaces of biochar [146]. Furthermore, a number of carbon–based materials have shown promise as oil adsorbents, including graphene, mesoporous carbon, and carbon nanotubes. The potential for creating effective and tailored solutions for the remediation of oil contamination is demonstrated by these various materials and approaches. To remove kerosene from water, researchers have examined polyethylene on magnetite multiwalled carbon nanotubes (Figure 3) [21]. A magnetite/nanotube nanocomposite was created by functionalizing multiwalled carbon nanotubes with strong nitric acid and then depositing magnetite nanoparticles on surface of the carbon nanotubes. A unique polyethylene/magnetite/nanotube nanocomposite was then created by adding polyethylene to the nanocomposite. Adsorption tests were conducted using simulated kerosene wastewater. During adsorption studies, a number of parameters were examined, including adsorption time, initial pH, adsorbent dose, kerosene content and temperature. Using batch experiment, high–performance liquid chromatography was used to measure the kerosene content. The adsorbent was removed using a magnetic field. The adsorption capacity for kerosene was 3560 mg/g, with removal efficiency of 71%, higher than 2092 mg/g and 42%, respectively, obtained for unmodified adsorbents. According to the Langmuir isotherm model and a pseudo-second-order kinetic model (R² = 0.99), the adsorption of kerosene was a homogenous and uniform process [21].

Another study examined the removal of kerosene from wastewater using multi–walled carbon nanotube/poly–N–isopropyl acrylamide–co–butyl acrylate/magnetite (Fe₃O₄) nanocomposites (Figure 4) [150]. After oxidizing the nanotubes using a solution of HNO₃ and H₂SO₄, they were coated with magnetite and then added poly–N–isopropyl acrylamide–co–butyl acrylate (P–NIPAM) to create nanocomposites known as P–NIPAM/Fe/carbon nanotubes. In comparison to the unmodified nanotubes, the nanocomposites demonstrated a higher adsorption capacity, increased surface hydrophobicity, and a 95% kerosene removal effectiveness. This value is higher than that obtained by pure carbon nanotubes (45%), those only oxidized (55%) and those decorated with magnetite (68%). For the removal of kerosene from wastewater, the nanocomposites (P–NIPAM/Fe/carbon nanotubes) demonstrated an adsorbent capacity of 8.1 g/g. At a pH of 3.5, an adsorbent dose of 0.005 g, a temperature of 40 °C, and a time of 45 min, the maximum kerosene removal efficiency from wastewater was achieved. The nanocomposites demonstrated exceptional stability during four cycles of regeneration. The polymer’s increased positive charge at pH 3.5 and the adsorbent’s increased adsorption affinity for the kerosene pollutant could be the cause. The Pseudo-second-order model was considered the most suitable for describing the adsorption kinetics [150].

The same group of scientists also conducted another study in which they examined the promoting effect of metal oxides (V₂O₅; M_xO_y = TiO₂) on multi–walled carbon nanotubes for the removal of kerosene from contaminated water [151]. The first step involved impregnating the functionalized multi–walled carbon nanotubes with 2% wt. of metal oxides (M_xO_y = TiO₂, V₂O₅, respectively). The authors discovered that TiO₂/functionalized multi–walled carbon nanotubes, among other options, had outstanding adsorption efficiencies for removing kerosene from wastewater by up to 84%. This could be because the surface area of the TiO₂ nanoparticles was increased through functionalization with strong acids. Additionally, the maximum adsorption capacity was 10.6 mg kerosene/g. The adsorption mechanism is based on hydrogen bonding between the hydrogen atom of kerosene and the oxygen atoms of the metal oxide nanoparticles on the functionalized nanotubes which increases the adsorption removal efficiency [151].

The different naturally inorganic minerals, such as vermiculite, perlite [152], zeolites [153], graphite [154], diatomaceous earth and bentonite [155], are employed as superior adsorbents to treat petroleum effluent and its byproducts because of their outstanding qualities, affordability, availability, non-flammability, and chemical inertness [156]. With particle sizes ranging from nanometers to millimeters, the natural mineral resources are usually utilized in granular or powder form. The structural properties, such as mesopore contribution, specific surface area, bulk density, particle size distribution, viscosity, and adsorbate density, affect the adsorption capacity [157]. Through a variety of processes, including capillary action, the creation of oil layers (films), and efficient pore filling in the regions around the adsorbent particles and external surfaces, oily substances adsorb onto the porous surfaces of minerals [156]. However, the majority of mineral materials have polar surfaces that make them hydrophilic and oleophobic in aqueous conditions, which prevents oil contaminants from adhering to them. Adding surfactants to these materials has been found to be a successful strategy for raising the inorganic mineral materials’ adsorption effectiveness. This alteration improves the material’s attraction to oils and organic contaminants by turning its hydrophilic surface into a hydrophobic one [158]. Quaternary ammonium ions have shown impressive oil removal properties and have been thoroughly investigated for clay modification. For instance, in 30 min, a long-chain modified organoclay removed 99% of the pollutant [159]. It is crucial to remember that better adsorption qualities can not necessarily result from surface modification using quaternary ammonium salts. In certain instances, obstructing the majority of the mineral’s pores during the surface modification process may result in a decrease in the mineral’s specific surface area and, consequently, its ability to adsorb oil. Consequently, more research is needed to fully understand the function of quaternary ammonium modification [160]. Additionally, the sorption process is greatly influenced by the chemical and physical characteristics of the organic materials themselves. varied pollutants showed varied levels of adsorption affinity, according to a study on the adsorption of ethylbenzene, benzene, xylene, and toluene by diatomaceous earth. This study demonstrated a clear correlation between adsorption on hydrophobicity and pollutant equilibrium [161]. An adsorbent made from clay and sawdust was used to examine adsorption of kerosene [162]. Three formulations of clay and sawdust with codes R17:3, R9:1, and R4:1 were tested in order to determine the ideal mixing ratio for removing kerosene. The findings showed that the sawdust and clay combination was more effective than only clay. Since the R4:1 formulation that is, 20% sawdust and 80% clay performed better than the other mixing ratios at any initial concentration of kerosene in wastewater. Additionally, the Langmuir isotherm best described the adsorption process of kerosene. As a result, with an initial kerosene concentration of 81 mg/mL the adsorption capacity for the clay was 81.6 mg/g and, lastly, the capacities for R9:1, R17:3, and R4:1 were 134.1, 143.4, and 150 mg/g, respectively. Consequently, the clay and sawdust mixture effectively removes kerosene from water, making it suitable for use specifically in the restoration of kerosene-polluted water [162].

The remarkable ability of cellulose-based materials to absorb oil and grease has led to an increase in study into these materials [163]. The physical characteristics of cellulose itself are exceptional, including its high Young’s modulus (114 GP) and specific surface area (37 m²/g), polymerization (14,400), and crystallinity (89%) [163]. There are numerous sources of natural cellulose, such as bacterial cellulose, plants, and algae. Due to their ease of extraction and large-scale production, plant fibers provide an affordable alternative with a high capacity for oil absorption [164]. The structure of cellulose–based materials is usually loose, porous, and network–like. These structures use capillary action to capture and adsorb oils within the gaps of cellulose–based materials when they come into contact with them, creating a stable adsorption state [165]. For instance, with a claimed absorption capability of 30 g/g, raw cotton, a cellulose–based material with a high yield and low cost, has shown good adsorption of crude oil [166]. The oleophilicity and hydrophobicity of cellulose–based materials can also be improved by chemical modification techniques such graft copolymerization, esterification, etherification, etc. [167]. Additionally, cellulose–based aerogels were created by treating them with sodium hydroxide and urea, then modifying them with methyl–trimethoxysilane. The greatest crude oil adsorption capacity of these modified aerogels was 24.4 g/g [168]. Another interesting biomass–based adsorbent material is lignin. With a three–dimensional network structure, a huge number of active sites, and an abundance of reserves, it is the second greatest biomass resource found in plants. It has effective adsorption properties for organic contaminants and heavy metals in water after being modified chemically, physically, or biologically. To support resource recovery and environmental management, future studies should concentrate on the creation and improvement of these biomass–based compounds, such as pectin, starch, and chitosan.

Despite the many benefits of the adsorption process, there are still a lot of issues with the actual treatment. Despite adding a significant amount of adsorbent to the effluent, the optimal recovery has not been achieved [169]. Additionally, the adsorption effectiveness of recycled adsorbents is drastically decreased, which presents another difficulty. Numerous efforts have been made to increase the adsorbents’ capacity to be recycled. For instance, using a magnetic field to promote the recovery and separation of carbon compounds is accomplished by combining them with magnetite; nevertheless, these outcomes were reached in a laboratory setting [170]. Since the actual amount of wastewater is larger and more complicated, using magnetic separation of nanoadsorbents which will also keep metals in the water and result in secondary pollution is not feasible. Several techniques, including microwave irradiation, ozone oxidation, Fenton reaction, and ultrasound, have also been reported in the literature to restore the adsorption ability of recovered nanocarbon materials by applying external forces [171,172]. But there are still issues, such as bacterial growth, solute obstruction, and chemical spillover. Thus, it is critical to keep looking at ways to enhance the recycling of adsorbents made of nanomaterials. Natural mineral materials, such as zeolites, can replenish their adsorption capacity through simple burning, allowing for reuse for up to 10 cycles, in contrast to nanocarbon materials [173]. To restore adsorbent qualities, a variety of physical and chemical techniques have been employed. Elution using aqueous solutions or other chemical reagents is the primary method used in chemical methods (Figure 5). Mechanical processes like centrifugation and compression are examples of physical procedures that are used to extract oil and chemical molecules from solid adsorbents [167]. In addition to having a high capacity for adsorption, cellulose materials are easily recyclable and exhibit good biodegradation qualities without generating harmful byproducts. Furthermore, after adsorbing oil and grease, cellulose materials can be used as fuel, significantly reducing energy waste.

Sustainable development will be facilitated by nanocellulose–based composite materials, which are poised to become a new generation of high–performance, environmentally friendly adsorbents for the treatment of petroleum wastewater and its derivatives, including kerosene, given their overall adsorption efficiency, environmental benefits, and treatment costs. Furthermore, future adsorption treatment systems will become increasingly automated and sophisticated as information technology advances [150]. Adsorbent regeneration and selection techniques can be improved with data analysis and real–time monitoring, leading to reduced operating costs and increased treatment effectiveness.

3.4.2. Membrane Technology

The membrane separation process has shown remarkable results in the fields of gas separation, water sterilization and purification, and saltwater desalination [174]. Comparing membrane technology to other oily wastewater treatment methods, the former offers a smaller footprint, higher efficiency, and lower energy usage during the separation process. This method also separates water and oil directly and effectively without requiring a phase change. An efficient and practical method of treating wastewater from petroleum and its byproducts, such as kerosene, is membrane technology. Through pressure differentials, particle pollutants of different sizes are physically retained in membrane processes by means of porous structural materials. Based on pore size and operating pressure, membranes are frequently divided into four categories: nanofiltration, ultrafiltration, microfiltration, and reverse osmosis processes [175]. The main purpose of microfiltration is to efficiently collect the majority of bacteria, suspended debris, and protozoan cysts. Ultrafiltration, which is 10–100 times smaller than microfiltration and has pore diameters between 0.01 and 0.1 μm, can remove all solutes, bacteria, protozoa, and other pollutants from water while letting metal ions pass through. Hydrocarbons, suspended particles, and dissolved chemicals may be separated from petroleum wastes far more effectively with ultrafiltration, according to reports. Since nanofiltration has a narrower range of pore sizes than ultrafiltration, the separation of small organic molecules has improved much more [176]. With pore diameters of less than 0.001 μm, reverse osmosis membranes can efficiently absorb materials as small as 0.0001 μm, which can adsorb almost all ions while permitting only pure water to flow through. Oily wastewater is frequently treated using ceramic and polymer membranes. As membrane technology has developed, carbon and cellulose–based membranes have become more well–known for their efficiency in improving membrane separation procedures for the treatment of effluent from petroleum. The development of membrane–based solutions for the effective and sustainable treatment of wastewater contaminated by oil is being propelled by ongoing improvements in membrane technology and manufacturing techniques. The benefits and drawbacks of membranes are thoroughly discussed in

Table 6. Benefits and drawbacks of membranes composed of various materials.

Membrane Materials	Applications	Advantages	Shortcomings	Reference
Carbon–based membrane	Oil-water emulsion	Hydrophobic, oleophilic and large specific surface area, highly integrated operation, mechanical stability, superior chemical and low raw material cost	Complex membrane cleaning process, unable to be mass produced and high cost	[177]
Polymer-based membrane	Dispersed oil and particles, emulsified	Promising mechanical properties, easily adjustable surface chemistry and pore size, energy consumption and low cost	Short life cycle, thermal stability and low chemical	[128]
Fiber–based membrane	Emulsion, Immiscible water-oil mixtures	Eco-friendly, renewability, high specific strength, light mass, flexible and cheap	Serious membrane pollution, structural vulnerability and weak mechanical stability	[178]
Ceramic membrane	Suspended oil and total suspended solids	Long service life, excellent thermal and chemical stability and high selectivity	Poor abrasion resistance, easily broken and brittle, heavy mass, expensive raw materials and operating costs	[179]

.

It is essential to take into account the treatment of petroleum effluent and its byproducts, such as kerosene and carbon recycling, from an economic standpoint. Because of their superior chemical stability, low cost, mechanical stability, and adaptable operational characteristics, carbon–based nanomaterials have been a major focus for membrane scientists. The special qualities of graphene and carbon nanotubes, such as their huge specific surface area, one-dimensional structure, hydrophobicity, and lipophilicity, make them particularly useful in applications involving the removal of greasy materials like kerosene [180]. Adding carbon nanotubes to composite membranes can greatly increase the membrane’s oleophobicity, hydrophilicity, mechanical strength, and thermal stability [181]. For instance, employing vacuum filtration, have created graphite oxide–based ultrafiltration membranes with a polyamide carrier, membranes with increased stability and water flux. Despite their effective separation capabilities, these composite membranes may be susceptible to structural deterioration in unfavorable conditions [182]. The carbon–based membranes, on the other hand, are valued for handling petroleum effluent because of their remarkable resilience in harsh conditions that include acids, solvents, alkalis, high pressures, and temperatures. When it comes to cleaning petroleum effluent under high pressure, researchers have successfully created carbon membranes based on activated carbon that exhibit encouraging outcomes [183]. However, the current high cost of recycling carbon–based films make their industrial–scale adoption difficult. Even though carbon–based nanoparticles have several benefits for wastewater treatment and oil-water separation, there are still issues with scalability in the recycling process and economic viability. In order to facilitate wider applications, future research should concentrate on improving the stability and longevity of carbon–based membranes as well as lowering production costs. Figure 6 shows the scheme for carbon nanotubes used in fuel filtration and dehydration [184].

For the ppm level water dehydration of kerosene, carbon nanotubes were immobilized on polytetrafluoroethylene and polyvinylidene difluoride microfiltration membranes to create very hydrophobic membranes. The shape, hydrophobicity, porosity, and permeability of the membrane were examined in relation to varying concentrations of carbon nanotubes. The contact angle increased by 9, 16, and 43% after carbon nanotubes were immobilized on the membranes in comparison to the unaltered 0.1 μm polytetrafluoroethylene, 0.22 μm polytetrafluoroethylene, and 0.22 μm polyvinylidene difluoride membranes, respectively. The immobilized carbon nanotube membrane showed exceptional fuel–water system separation efficiency. Higher water rejection was achieved as a result of the micro/nano water droplets forming bigger diameters on the carbon nanotube surface and separating from the membrane surface. As the quantity of immobilized carbon nanotubes increased, the water rejection generally rose, while the effective surface porosity over the pore length and flux dropped. The membrane based on polytetrafluoroethylene performed better than the one based on polyvinylidene difluoride. With 0.1 and 0.22 μm polytetrafluoroethylene and an optimal carbon nanotube loading of 3 and 6% wt., the carbon nanotube–immobilized membranes were created. The kerosene fluxes were 43 kg/m² h and 55 kg/m² h, respectively, and the water rejection was 99 and 97% [184].

Researchers used ultrafiltration membranes to treat kerosene from wastewater emulsion [185]. The emulsion was ultrafiltered, and the impacts of several parameters, such as membrane type (polysulfone and regenerated cellulose), kerosene content, transmembrane pressure, pH, and feed flow velocity, were examined. It was discovered that the three main variables influencing ultrafiltration were: membrane type, pressure, and initial concentration. The greatest flux under ideal circumstances was estimated to be 108 L/m² h, which is within the confidence limit of the measured value of 106 L/m² h, at 3% (v/v) initial concentration, 3 bar, and C30F membrane type. More hydroxyl groups were visible in the normalized Fourier transform infrared spectroscopy data of the virgin cellulosic membranes C100F and C30F. In comparison to the C100F membrane, the C30F membrane exhibits a higher flow, which is attributed to both a greater number of pores and a higher surface porosity. For all membranes, the flux was independent of pressure in the biased regime of 3 bar upwards and was thought to be dictated by back diffusion transport. The hydrophilic C100F membrane had a greater permeate flux even though the cutoff threshold of the PS100H and C100F membranes was the same at 100 kg/mol. Despite being hydrophilic, the C100F membrane showed the largest flow decline over time as a result of oil fouling. Both scanning electron microscopy and Fourier transform infrared spectroscopy demonstrated that cake layer production was not the reason for fouling in the PS100H membrane. In the meantime, the fouled C100F membrane’s characterization investigations revealed evidence of adsorptive fouling and gel formation [185].

Ceramic membranes are highly preferred due to their exceptional temperature and chemical stability, and long life [186]. Ceramic membranes’ hydrophilicity is greatly increased because of the abundance of surface metal hydroxyl groups. This results in superoleophobic or underwater oil repellent properties, which greatly increases the membranes’ resistance to kerosene and oil pollution. Furthermore, ceramic membranes exhibit exceptional resilience while handling oily effluent with high temperatures, organic solvents, and severe acidity or alkalinity. However, ceramic membranes are prohibitively expensive due to the high cost of raw materials like zirconia and alumina as well as high sintering temperatures that demand a large amount of energy, which severely restricts their widespread use [187]. Recent developments have increased the affordability and accessibility of ceramic membranes in industrial settings by substituting inexpensive clays such meerschaum clay, kaolin, dolomite, shale clay, and Algerian clay for raw materials [188]. The microstructural properties of ceramic membranes are inextricably tied to their separation performance. Microstructural characteristics including shape, porosity, and pore size distribution have a direct impact on the separation efficiency and flux of porous ceramic membranes. For instance, highly effective separation can be accomplished by ceramic membranes with consistently dispersed pore diameters. Additionally, asymmetric multilayer ceramic membrane architectures work exceptionally well in improving permeability selectivity [189]. For instance, using α–Al₂O₃/ZrO₂ as raw materials, researchers created a ceramic membrane with a hole size of 0.2 μm and achieved an amazing oil retention rate of 99% [190]. The removal rates were from 85 to 99% when ceramic microfiltration membranes with slightly higher pore sizes (1.3 μm) were made with kaolin clay [191]. Ceramic membranes must, however, balance permeability and selectivity. At initial concentrations below regulatory limits, then, it is crucial to maintain a high pollutant rejection rate while increasing water permeability to guarantee safe and environmentally risk–free release [192]. The application of ceramic membranes depends on their preparation technology, and at the moment, the most often utilized techniques are thermal evaporation, sol–gel, magnetron sputtering, and electrochemical deposition. The sol–gel technique is the most popular of them because it is inexpensive and easy to utilize [189]. Nevertheless, this technique still has drawbacks, including trouble regulating film thickness and excessive energy usage. In order to lower production costs and enhance membrane performance, future research will concentrate on improving these process parameters.

A high–performance antifouling asymmetric zeolite@polyethersulfone/cellulose acetate membrane was employed in a study to effectively separate kerosene containing greasy wastewater [193]. Oily wastewater was treated by a cross–flow microfiltration process with a membrane made of zeolite 4A (0.25–1 wt.%), activated carbon (2 wt.%), and polyethersulfone (17 wt.%) utilizing the non–solvent–induced phase inversion procedure. Pollutant rejection, permeation flux, pure water flux, percentage flux recovery ratio, and percentage relative flux reduction were used to evaluate the prepared membranes’ performance. It was determined that adding 4A zeolite nanoparticles to the polyethersulfone and activated carbon blended polymer greatly enhanced the membranes’ hydrophilicity and other structural characteristics, such as their low contact angle of 29° for 0.5% 4A zeolite, compared to 70° for pure polyethersulfone, and their porosity of 87% for 0.5% 4A zeolite, compared to 44.5% for pure polyethersulfone. With an initial concentration of 500 mg/L, a transmembrane pressure of 2 bar, a temperature of 25 °C, and a pH of 7.2%, the 4A@polyethersulfone/activated carbon zeolite membrane with 0.5 weight percent 4A zeolite nanoparticles (0.5% 4A zeolite membrane) demonstrated the highest pure water flux of 91 L/m²h and pollutant rejection of 98.8%. The antifouling properties of the polyethersulfone/activated carbon combination membrane were improved by the addition of 0.5 weight percent 4A zeolite nanoparticles. Conversely, the 0.5% 4A zeolite membrane demonstrated a relative flux drop of 21.8% and a flux recovery ratio of 97.7%. Depending on the concentration of the polymer blend in the manufacture solution, the benefit of employing 4A zeolite nanoparticles to boost the hydrophilicity of the polyethersulfone/activated carbon blend, kerosene rejection, and permeate flow is restricted by a certain zeolite content. When SDS was utilized as the cleaning agent, reuse studies of the 0.5% 4A zeolite membrane revealed that the membrane maintained an almost constant kerosene rejection rate of 94% after 5 cycles. However, after five cycles of cleaning with sodium hydroxide solution, the membrane maintained a 72% kerosene rejection rate [193].

Polymeric membranes are perfect for a range of separation processes, including the treatment of petroleum effluent, because they have exceptional mechanical strength and can be customized with certain surface chemistries and pore sizes. In membrane technology, polyacrylonitrile, polyvinylidene fluoride, polypropylene, and polysulfone are often utilized polymers [194]. Oil droplets have a propensity to clog the pores of traditional polymeric membranes, which reduces their permeate flux and shortens their operational life. In order to improve the performance of polymeric membranes, researchers have investigated a number of modification strategies that involve adding more materials or combining several technologies. A team of researchers studied the treatment of oilfield wastewater using polyvinylidene fluoride membranes modified with inorganic nanoalumina. The results demonstrated that the treated water achieved over 90% chemical oxygen demand elimination and over 98% total organic carbon removal, with grease, oil, and suspended particles contents below 1 mg/L [195]. Another study modified polysulfone membranes by adding chemicals such polyethylene glycol and polyvinylpyrrolidone, which increased the membranes’ porosity and hydrophilicity. According to experimental results, the modified membranes retained more than 90% of the oil [196]. Hydromanganese oxide nanoparticles were incorporated into polyvinylidene fluoride membranes to create hydromanganese oxide nanoparticle/PDVE ultrafiltration membranes. When compared to the performance of unmodified PDVE membranes, this alteration resulted in a notable tenfold increase in water flux and 93% grease and oil retention [197]. The complexity of oily wastewater’s composition raises the strain placed on membranes in proportion. Consequently, the creation of novel, high–performance polymer membrane materials and eco-friendly polymers like chitosan, polylactic acid [198], cellulose acetate [199] and new membrane preparation techniques (thin film deposition) [200], is of great importance.

A study created a hydrophobic bilayer/hydrophilic nanofibrous membrane that was utilized in a direct contact membrane and had catalytic properties [201]. The membrane was thoroughly described in terms of both its shape and chemical makeup. Computational fluid dynamics simulations and heat transfer studies were employed to explain the water flux augmentation of the hydrophilic/hydrophobic bilayer nanofibrous membrane. A hydrophilic/hydrophobic bilayer nanofibrous membrane’s antifouling properties were examined using kerosene and aniline, two common pollutants found in shale gas effluent. This membrane’s antifouling properties were assessed using the computational fluid dynamics simulation calculation and the expanded Derjaguin–Landau–Verwey–Overbeek theory, respectively. Kerosene, pure NaCl, and aniline were among the three kinds of feed solutions that were processed. The hydrophilic/hydrophobic bilayer nanofibrous membrane demonstrated a greater water flux for the NaCl feed than the slurry membrane (13 vs. 10 kg/m² h). This was because the hydrophilic layer’s high thermal conductivity made it easy to raise the membrane’s surface temperature and evaporate the water on it. After 10 h of operation, the hydrophilic/hydrophobic bilayer nanofibrous membrane’s flux for the oil-containing feed remained at over 90% of its initial flow, but after 4 h, the membrane’s normalized flux dropped sharply to 0 kg/m² h. According to theoretical study, the hydrophilic/hydrophobic bilayer nanofibrous membrane’s strong hydration ability and low adhesion free energy were responsible for its oil antifouling effect. The hydrophilic/hydrophobic bilayer nanofibrous membrane was able to completely break down aniline by activating peroxymonosulfate when it came to treating feeds that included aniline. According to electron paramagnetic resonance spectroscopy, highly oxidative radicals (SO₄^•−, ^•OH) are essential for aniline elimination [201].

Because of their many benefits, fiber–based membranes have drawn a lot of interest in the oil–water separation industry. These membranes are made up of interwoven, cross-linked fibers that create a tortuous network of pores. The kind of fiber and the size of the pores determine how well fiber–based membranes work [202]. In terms of fiber content, inorganic and organic fiber membranes are the two primary types. Numerous studies have been conducted on inorganic fiber membranes, including carbon nanotube wire mesh and inorganic oxide fibers [178]. Their exceptional mechanical strength and chemical stability make them appropriate for demanding operational environments [178]. But for water–oil separation, inorganic materials by themselves frequently lack sufficient selectivity. Several techniques are used to improve the membrane surface’s wetting characteristics in order to increase their performance. For instance, metal mesh films with surface micro–nanostructuring have increased surface roughness and improved wettability [203]. By using a sol–gel technique to coat titanium dioxide nanoparticles on carbon nanotube membranes, oleophobicity and hydrophilicity are greatly increased, leading to a high rate of water–oil separation [204]. Despite having outstanding oil–water separation capabilities, inorganic fiber membranes frequently have issued such brittleness, low elasticity, high weight, and huge volume. They have limitations that limit their use in applications that require flexibility and resilience. Membranes composed of organic fibers are lightweight and flexible. Superior mechanical qualities, a high capacity to absorb water and oil, naturally porous architectures, and production scalability are all features of fabrics made from organic fibers, such as cotton. Functionalized cotton fibers have shown a 97% separation efficiency when utilized as materials for oil-water separation [205]. The strengths of various organic fiber membrane types vary; for instance, nylon fiber membranes have a high specific strength, but natural fiber nonwoven membranes and electrostatically spun fiber membranes are recognized as renewable and eco-friendly alternatives [206]. In conclusion, each type of fiber membrane organic and inorganic has special benefits for applications involving the separation of water and oil. The difficulty of treating high–concentration organic wastewater, which necessitates lowering energy usage and further enhancing fouling resistance, is one of the many obstacles that these technologies still confront despite their enormous application potential. Last but not least, attaining resource utilization and wastewater recovery is a crucial area of future study.

Although membrane–based methods provide almost total oil–water separation, membrane fouling which is brought on by oil droplets interacting with the membrane surface makes it difficult to sustain performance over extended periods of time. Several ways have been examined as potential solutions to solve membrane fouling difficulties, including surface modification, membrane materials, chemical cleaning, aperture restructuring, and backwashing. Ceramic membranes have significant oleophobicity and antifouling qualities by nature, and surface coating can improve these qualities even more. Researchers created perovskite nano titanium dioxide coatings on the surface of alumina ceramic membranes using the sol–gel technique [207]. The membranes demonstrated improved wettability and self–cleaning properties under the combined influence of UV radiation, all the while preserving superior separation performance. Because of the surface water layer, cellulose membranes have exceptional oleophobic qualities. Oil deposition is prevented by the hydration layer, which breaks the hydrophobic-hydrophobic interactions between the surface and oil droplets [208]. On the other hand, polymer and carbon-based membranes have less antifouling capabilities and are more prone to contamination by greasy materials [209]. Enhancing hydrophilicity is a crucial strategy for lowering oil contamination on the membrane surface, according to several research. Copolymer-based graft changes in PVDF membranes, for instance, have significantly enhanced their oleophobicity, hydrophilicity, and antifouling capabilities [210]. Furthermore, sewage flow can be changed from laminar to turbulent using physical modification techniques, such as forming a three-dimensional pattern on the membrane surface. This reduces membrane fouling and the aggregation of oil molecules on the membrane surface [211]. Underwater superoleophobicity has also been seen on fish scale surfaces, and researchers attribute this to the presence of hydrophilic mucilage and nano- and microstructures. By covering commercially available metal meshes with adjustable pore sizes with graphene oxide, they were able to create superoleophobic membranes [212]. For oil-water separation, these novel methods show promise in enhancing long-term performance and reducing fouling in membrane-based technologies. For membrane-based oil-water separation technologies to become more sustainable and effective, more research and development in materials engineering and surface modification techniques will be essential.

4. Nanomaterials and Engineered Composites

4.1. Role of Nanotechnology in Improving Remediation

In recent years, there have been advancements in the field of materials science that have provided an avenue for developing highly functional materials for remediating hydrocarbon contaminated water. In this context, nanotechnology has provided a means for the synthesis of nanomaterials for removing these pollutants from wastewater [213]. At its core, nanotechnology provides the opportunity to develop materials at the nanoscale (1 to 100 nm), where materials exhibit characteristics distinct from their larger counterparts. The materials, so named nanomaterials, have a higher surface area to mass ratio than their larger counterparts, and they exhibit the development of quantum effects that significantly alter physical, chemical, and biological behaviors [214,215,216]. The ability to manipulate materials at the atomic and molecular levels has led to the creation of synthetic nanostructures and nanocomposites that outperform conventional materials in environmental applications [217,218,219].

An interesting observation occurs with nanomaterials when the particle size is reduced to less than 10 nm. The material exhibits behavior similar to that of individual atoms, resulting in discrete energy levels rather than the continuous energy levels observed in bulk materials [220]. This variation in the properties of nanomaterials compared to bulk materials is primarily attributed to factors such as the proportion of surface atoms, surface energy, spatial confinement, and structural imperfections [221]. Figure 7 is a graphical representation of the varied parameters that influence the properties of nanomaterials.

Nanotechnology represents an emerging discipline with extensive applications, providing a means for environmental cleanup. The distinctive properties of nanomaterials, which include higher surface area, superior electronic properties, and higher surface reactivity, facilitate their capacity for efficient removal of pollutants from wastewater, resulting in fewer toxic byproducts [107,222]. These materials are utilized to address the remediation of contaminants such as industrial waste, heavy metal ions, sewage, organic solvents, agrochemicals, and emerging pollutants like microplastics, pharmaceuticals, and petroleum hydrocarbons [223]. This approach provides effective, economical, and environmentally friendly methods to mitigate pollution and promote environmental sustainability. Younis et al. have classified this approach into three categories on the basis of the nanomaterial’s functionality: nano-membrane filtration, nanosorbents, and multi–functional techniques, including dispersants, oil adsorption, and catalytic degradation [224].

Recent studies on nanomaterials emphasize their wide range of applications, including nanoadsorbents for removing kerosene from wastewater [225,226], nanofilters for remediating oily wastewater [227,228], nanophotocatalysts for removing chemical oxygen demand (COD) from refinery wastewater [229], and nanomembranes for oily wastewater treatment [230,231]. Employing nanomaterials for treating can be more efficient and cost–effective than traditional methods [232]. Among nanomaterials, the literature predominantly focuses on carbon nanotubes [21,233,234], graphene oxides [235,236], and metal oxide nanoparticles [237,238] for the removing hydrocarbons from aqueous media.

Recent advancements show the exceptional prospects of nanostructures in improving remediation processes. A few studies have shown the important role of nanostructured adsorbents in enhancing kerosene removal, offering improved removal efficiencies, faster kinetics, and better regeneration capabilities compared to traditional techniques. For instance, Abdullah et al. investigated the development of a polyethylene over magnetite-functionalized multiwalled carbon nanotubes [21]. In studied system, multiwalled carbon nanotubes functionalized with nitric acid were combined with magnetite (Fe₃O₄) nanoparticles and further incorporated with polyethylene to yield a novel composite material (PE/Fe–MWCNTs). The developed nanoadsorbent showed a kerosene removal efficiency of 71.2% and an adsorption capacity of 3560 mg/g, outperforming other forms of MWCNTs and Fe–MWCNTs composites. Similarly, Abdullah et al. integrated poly–N–isopropyl acrylamide–co–butyl acrylate (P–NIPAM) with Fe₃O₄–decorated MWCNTs to obtain nanocomposites with high kerosene removal efficiency [150]. Comparatively, these synthesized P–NIPAM/Fe/MWCNTs yielded a higher kerosene removal efficiency of 95% and an adsorption capacity of 8100 mg/g under optimized conditions, maintaining stability over multiple cycles due to their enhanced hydrophobicity and surface charge modulation at low pH [150]. Patinõ–Ruiz et al. reported the synthesis of iron oxide (FeO) and titanium dioxide (TiO₂) nanoparticles–modified chitosan beads to yield Ch–FeO/TiO₂ [239]. The performance of the synthesize nanomaterial was evaluated by extracting naphthalene from both sea and freshwater samples. The nanomaterial demonstrated a higher adsorption capacity of 33.1 mg/g, in contrast to 29.8 mg/g for the pristine chitosan beads. This adsorbent was recognized as a cost–efficient and environmentally friendly solution for cleaning water sources polluted with complex hydrocarbon compounds. In a separate study, Ko et al. [240] devised a technique for removing oil droplets from water using magnetic nanoparticles coated with a cationic surface. Through batch adsorption studies carried out using a 5 wt.% decane in water emulsion, they reported a decane droplet removal efficiency of up to 99.99% [240,241].

The role of nanotechnology in advancing the treatment of hydrocarbon effluents has become increasingly evident through recent studies. It has been established that nanomaterials offer significant advantages due to their tunable properties, high surface area, and higher reactivity, collectively enabling more effective pollutant removal compared to traditional bulk materials [217]. The development of advanced nanocomposites, such as carbon nanotubes functionalized with magnetite and adsorbents modified with polymers, has resulted in significant improvements in adsorption capacities and removal efficiencies for kerosene and similar hydrocarbons [150]. These show enhanced regeneration capabilities, stability under diverse environmental conditions, and usability to low pH values.

4.2. Nanomaterials Used in Remediating Kerosene–Contaminated Water

The application of nanomaterials for treating waste effluents offers a promising solution in the treatment of wastewater polluted with kerosene. The various types of nanomaterials including carbon–based nanostructures, metal–based nanoparticles, zeolite, biopolymers, MOFs, metal oxides, and composite nanomaterials, etc., have been reported for the removal of kerosene [232]. Each class of nanomaterial offers distinct advantages and mechanisms of action, ranging from adsorption and photocatalysis to chemical degradation and separation.

4.2.1. Metal Oxides

The metal oxide-based nanomaterials are distinguished by their high surface area, variable oxidation states, tunable surface functionalities, and potential for multifunctionality, which collectively make them highly effective in complex treatment environments [242,243,244]. The metal oxides demonstrate not only excellent sorption and separation capabilities but also additional functionalities such as photocatalytic degradation and antimicrobial activity [245]. This section critically reviews representative studies that explore the application of metal oxide nanomaterials to remediate kerosene contaminated water.

Gao et al. reported the fabrication of a hybrid composite adsorbent using industrial fly ash modified with calcium hydroxide (Ca(OH)₂) and sodium ferrate (Na₂FeO₄) [246]. This dual-functional material was used to achieve kerosene adsorption capacities as high as 17.2 g/g after 40 min. of adsorption. The utilization of fly ash, an available industrial by-product, presents a cost-effective and sustainable approach for developing multifunctional adsorbents. The modification process enhanced the porosity and surface chemistry of the fly ash, facilitating hydrophobic interactions with kerosene molecules. Obaid et al. [247] prepared silica–based electrospun polysulfone (PSF) nanofiber membranes for enhanced kerosene separation. The incorporation of silica facilitated the separation of the kerosene–water mix with a daily flux of 115 m³/m²/day. The improved separation performance was attributed to the increased surface roughness, hydrophobicity, and porosity introduced by the SiO₂ nanoparticles. These findings highlight the effectiveness of nanostructured metal oxides in enhancing membrane functionality for continuous phase separation applications. The role of silica in increasing porosity and hydrophobicity is seen to be a recurring theme in future works, where nanoparticle incorporation was reported to drive interfacial phenomena which was important for separation.

Yang et al. developed a superhydrophobic sponge architecture featuring in situ chelated ZnO and Ag nanoparticles [248]. The sponge demonstrated exceptional kerosene adsorption capacities ranging from 33.9 to 135.2 times its weight, with the removal efficiency reaching as high as 99.87%. In addition, a 97.07% photodegradation efficiency was reported after exposure to solar radiation for 4 h. The material also maintained structural and functional integrity over repeated use, making it a strong candidate for both passive and active remediation strategies. Wahid et al. enhanced the functionality of metal oxide-based systems by integrating zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles into bacterial cellulose (BC) membranes [249]. These composite membranes achieved oil–water separation efficiencies greater than 99.9% and also exhibited photocatalytic and antibacterial properties. The incorporation of TiO₂ and ZnO not only facilitated physical separation but also allowed for the photodegradation of organic pollutants under UV irradiation, offering a comprehensive solution for wastewater treatment in mixed-contaminant scenarios. Huang et al. [250] demonstrated the fabrication of aerogel composites composed of silica–based aerogels. The aerogel, produced by combining silica with MWCNT was reported to remove as much as 22.5 cm³ (oil)/g, making them highly relevant to hydrocarbon remediation. The hierarchical porous structure of the aerogels allowed for rapid uptake and retention of oil, suggesting potential scalability for industrial effluent treatment. 7–octadiene–doped silica nanoparticles were evaluated for the removal of kerosene from water. The material was reported to remove over 99.5% of kerosene from the aqueous medium within 30 s of contact time [251]. The ultrafast separation time, combined with the low energy requirements of plasma–based fabrication method, positions this approach as a promising candidate for emergency spill response and rapid treatment. Wang et al. coated natural fabrics with a combination of silica and alkali-treated zeolite to produce a flexible, reusable oil–water separation medium [252]. The material achieved 99.4% efficiency for kerosene and exhibited underwater superoleophobicity. The material’s reusability and compatibility with low-cost materials underline recommended it for decentralized treatment applications.

All studies show the versatility and multifunctional characteristics of metal oxide nanomaterials in the treatment of kerosene contaminated effluents. Metal oxides including zinc oxide (ZnO), titanium dioxide (TiO₂), silica (SiO₂), and iron-based oxides have proven effective as platforms in this regard. Together with natural substrates or polymer matrices, these materials not only efficiently remove hydrocarbons but also address secondary issues such as microbial contamination and organic degradation, thereby offering comprehensive solutions to complex wastewater treatment challenges. The materials presented in

Table 7. Summary of some metal oxide-based nanomaterials for kerosene remediation.

Material	Composition	Removal Performance	Functionality	Reference
Fly ash nanocomposite	Fly ash + Ca(OH)2 + Na2FeO4	17.2 g/g adsorption capacity	Simultaneous dye removal, cost-effective	[246]
Nanofiber membrane	PSF + SiO2 nanoparticles	115 m3/m2/day separation flux	Increased hydrophobicity, roughness	[247]
ZnO–Ag superhydrophobic sponge	Sponge + ZnO + Ag nanoparticles	33.9–135.2 g/g adsorption, 99.87% oil separation	Photodegradation (97.07%), reusable	[248]
BC membrane nanocomposite	Bacterial cellulose + TiO2 + ZnO	>99.9% separation efficiency	Photocatalytic and antibacterial	[249]
Silica aerogel	Silica aerogel + MWCNTs	22.5 cm3/g oil removal	Hierarchical porosity, rapid uptake	[250]
7–Octadiene–doped silica	Doped silica nanoparticles	>99.5% removal in 30 s	Fast separation, low energy fabrication	[251]
nanocomposite)	Natural fabric + silica + zeolite	99.4% separation efficiency	Reusable, underwater superoleophobicity	[252]

demonstrate multifunctionality and performance for specific applications.

4.2.2. Carbon Nanomaterials

The carbon–derived nanomaterials effectiveness stems from attributes such as large surface area, adjustable porosity, high chemical reactivity, and potential for surface modification [245]. Among the most extensively studied carbon nanomaterials are multi-walled carbon nanotubes, activated carbon, and carbon aerogels, which offer flexibility in design and multifunctionality. Through hydrophobic interactions, π–π interactions, hydrogen bonding, electrostatic interactions, and covalent interactions carbonaceous nanoparticles effectively absorb organic pollutants [253].

Carbon nanotubes (CNTs) have received the most attention in remediation of waters contaminated with kerosene. Garg et al. reported that CNTs are the most widely studied carbonaceous nanoparticles, and noted that there are four different sites for adsorption of contaminants: the inner site, the interstitial channel, the peripheral groove, and the external surface [254]. Furthermore, it was observed that organic pollutants, including those with benzene rings, polycyclic aromatic hydrocarbons (PAHs), polar aromatic molecules, and C=C bonds, are rapidly adsorbed onto the surface of CNTs. Expanding on these fundamental insights, Abdullah et al. synthesized a smart nanocomposite based on MWCNTs decorated with Fe₃O₄ nanoparticles and coated with a poly(N–isopropylacrylamide-co-butyl acrylate) (P–NIPAM) polymer [150]. This material exhibited enhanced kerosene adsorption (95% efficiency, 8.1 g/g capacity), after 45 min, 240 rpm, 0.005 g of the nanocomposite adsorbent, and temperature of 40 °C. The material demonstrated stability over four reuse cycles. Abdullah et al. reported the application of MWCNT-based nanocomposites as adsorbents for the removal of hydrocarbons such as kerosene from water [255]. Pristine MWCNTs and its modified versions (V/MWCNTs, Ce/MWCNTs, and Ce:V/MWCNTs) were employed to remove kerosene from solution. The results demonstrated that V:Ce/MWCNTs achieved a kerosene removal efficiency of 85% and an adsorption capacity of 4270 mg/g after 60 min, surpassing the performance of the other adsorbents produced. Kinetic analysis confirmed pseudo-second-order as dominant mechanisms. The synergy between metal oxide doping and the intrinsic porosity of MWCNTs led to increased active sites and improved molecular diffusion, illustrating a powerful approach for improving adsorption kinetics and capacity. Further mechanistic insights were offered in a similar study by Abdullah et al. who evaluated the promotional influence of TiO₂ and V₂O₅ on MWCNTs for the removal of kerosene [151]. The TiO₂/MWCNTs gave the highest kerosene removal efficiency of 84% while V₂O₅/MWCNTs achieved 80%. It was proposed that the mechanism driving the adsorption of kerosene in as-prepared MWCNTs, was the van der Walls forces between the carbon atoms of kerosene and the adsorbent. However, for the metal oxide doped MWCNTs, the driving mechanism was the hydrogen bonding formed between the hydrogen atom of kerosene and the oxygen atoms of the adsorbent.

Beyond oxide doping, surface functionalization using organic modifiers also offers promising routes. Al-Jammal et al. applied a microemulsion technique to graft hydrocarbon tails onto MWCNTs, forming µEMWCNTs [256]. This process enhanced kerosene adsorption capacity by 63.5% over unmodified CNTs without requiring complex post-synthesis treatments. The increased hydrophobicity, achieved through CH–π interactions, improved compatibility with nonpolar kerosene molecules, suggesting a simplified yet effective strategy for functional enhancement. Structural configuration also plays an important role in determining adsorption efficiency as seen in the work of Fan et al. who reported the fabrication of vertically aligned carbon nanotubes (VA–CNTs) [257]. These exhibited a kerosene adsorption capacity of 69 g/g, outperforming agglomerated CNTs (41 g/g) [257]. Their unique architecture, which provided large macropores and superior mechanical strength, enabled easy regeneration through mechanical squeezing. This approach combines high performance with reusability and operational simplicity, aligning well with field deployment needs for oil spill cleanup. While the foregoing studies focused on material performance and compositional innovation, Liu et al. [258] addressed the regenerative potential of raw MWCNTs. Their findings revealed that incinerated MWCNTs outperformed extruded ones in re-adsorption capacity, likely due to preservation of nanotube morphology during incineration. Additionally, oil adsorption improved with increasing hydrocarbon chain length, metal ion concentration, and surfactant presence. This work highlights the influence of external factors and post-use treatment methods on the lifecycle performance of CNT-based adsorbents.

Beyond CNTs, biomass–derived carbon materials have also received some attention. For instance, Sahlabadi et al. recently evaluated the adsorption efficiency of activated carbon alongside biosorbents derived from jujube and barberry tree stem powders [143]. While activated carbon demonstrated superior kerosene removal efficiency of 99.02%, the biosorbents also exhibited promising performance, with barberry and jujube achieving 83.87% and 68.48%, respectively [143]. The pseudo-second-order kinetics was the major mechanism driving the process which suggested chemisorption as the dominant mechanism, and conformed to multilayer Freundlich isotherm model. This study not only reaffirms the high performance of activated carbon, but also introduces bio-derived alternatives that offer sustainable and low-cost options, albeit with a lower adsorption capacity.

The versatility of carbon nanomaterials, particularly multi-walled carbon nanotubes, has been attributed to their customizable structure, potential for surface modification, and compatibility with various functionalization techniques, including metal oxide doping, polymer coating, and organic grafting. As shown in

Table 8. Summary of some carbon nanomaterials for kerosene removal from aqueous systems.

Material	Composition and Structure	Kerosene Removal Performance	Functionality	Reference
Fe3O4–PNIPAM/MWCNTs	MWCNTs + Fe3O4 + P-NIPAM polymer	95% removal, 8.1 g/g capacity	Smart polymer, magnetic recovery	[150]
μEMWCNTs	Microemulsion-grafted hydrocarbon chains on MWCNTs	63.5% increase over pristine CNTs	CH–π interactions, improved hydrophobicity	[256]
TiO2/V2O5–MWCNTs	MWCNTs + TiO2 or V2O5	TiO2: 84%, V2O5: 80% removal	Hydrogen bonding with kerosene	[151]
V:Ce/MWCNTs	MWCNTs + vanadium + cerium	4270 mg/g adsorption, 85% efficiency	Metal doping, enhanced diffusion/kinetics	[255]
VA–CNTs	Vertically aligned CNTs	69 g/g (vs. 41 g/g for agglomerated CNTs)	Structural orientation, reusability	[257]
Activated carbon/biosorbents	Activated carbon, barberry, jujube stem powders	AC: 99.02%; Barberry: 83.87%; Jujube: 68.48%	Pseudo-2nd-order kinetics, Freundlich isotherm	[143]

, these systems achieve high removal efficiencies through complementary mechanisms such as hydrogen bonding, π–π stacking, and hydrophobic interactions, which are specifically tailored to the properties of kerosene. Innovations in structure, such as vertical alignment, along with considerations for regeneration, further enhance their practical utility. Moreover, the increasing interest in biomass-derived alternatives indicates a shift towards sustainability. Collectively, these advancements suggest that carbon nanomaterial technologies are advancing and are poised for scalable, multifunctional water treatment applications.

4.2.3. Magnetic Nanoparticles

Recent research has given attention to the application of magnetic nanoparticles (MNPs) in wastewater treatment, with their performance attributed to their ease of separation, specificity in targeting contaminants, high adsorption efficiency, compatibility with biological systems, potential for reuse, large surface/volume ratio, and minimal maintenance requirements [259]. The magnetic properties of MNPs are particularly beneficial for water purification, as they can modify the physical and chemical characteristics of pollutants in aqueous solutions. In addition, it can also affect the interface between solid and liquid phases during the adsorption process [260]. The magnetic field can cause significantly impact the adsorptive removal of pollutants from water which can in turn influence the time required to reach saturation and the amount adsorbed/unit mass [261].

Studies have shown that magnetic nanoparticles can be tailored into superhydrophobic absorbents for selective and efficient oil-water separation. They have received some attention the adsorption of kerosene. In one of such studies, Dai and Li reported the synthesis of magnetic composite nanospheres for stabilizing kerosene emulsions [262]. The magnetic composite nanospheres synthesized via surface-initiated RAFT polymerization were responsive to pH, temperature, and magnetic fields. They were reported to show excellent magnetic responsiveness, acting as efficient pickering emulsifiers capable of stabilizing kerosene emulsions and enabling their reversible separation. When applied to the kerosene emulsion, the external magnetic field caused the magnetic nanoparticles to migrate or aggregate, which led to the breakdown of the emulsion (reversible separation). Furthermore, the emulsions were broken or re-formed by altering pH and temperature, allowing at least 10 reuse cycles with high recovery efficiency. Li et al. [263] reported the synthesis of a magnetic superhydrophobic melamine sponge based on magnetite nanoparticles using a drop coating method. The prepared sponge demonstrated a high adsorption capacity for kerosene (59 g/g), and could be magnetically controlled for recovery and reusability [263]. It was reported that the coating enhanced water repellence, enabling fast and selective adsorption of oil under both gravity-driven and magnetically induced conditions. Kamgar et al. synthesized Fe₃O₄@SiO₂@MPS nanoparticles by coating Fe₃O₄ with a silica layer followed by hydrophobic modification using trimethoxysilylpropyl methacrylate (MPS). The impact of core size on adsorption performance was studied by varying synthesis conditions. The optimized particles (MNP600) absorbed kerosene up to 4.84 times their own weight and were magnetically recoverable. The hydrophobic nature was validated by contact angle measurement (138°), but unlike the MNPLNA system reported by Li et al. [263], no reusability assessment was carried out. While the fabrication method was simpler, the oil removal capacity and functional sophistication were relatively lower [263]. Hence, compared with simple magnetic particles, functionalized and smart MNP systems like MNPLNA provide enhanced controllability, reusability, and emulsification capacity for wastewater remediation. Rezaei and Hassanajili, reported the facile synthesis of a superhydrophobic magnetic bio-sorbent [264], process consist in magnetizing of the corncob surface with CoFe₂O₄ nanoparticles by a co-precipitation method. The resulting magnetic composite demonstrated superhydrophobicity (water contact angle: 165°), outstanding magnetic responsiveness (saturation magnetization: 32 emu/g), and superoleophilicity (oil contact angle: 0°). The magnetic bio–sorbent exhibited kerosene adsorption capacity 5.5 times its weight. The adsorbent was recoverable and reusable for at least 10 cycles, maintaining desirable adsorption capacity and water contact angle.

4.2.4. Polymeric Nanomaterials

Recent advancements in polymer science have enabled the development of a polymeric materials exhibiting properties such as electroactivity and enhanced mechanical and thermal characteristics [265]. The properties of polymers can be modified for thermal, optical, toxicity, mechanical, biodegradability, and hydrophilic/hydrophobic balance, which can be tailored as desired depending on the polymer selected [226]. Collectively, these properties render polymer-based nanoadsorbents highly hydrophobic and oleophilic, which is essential for oil selectivity and the capacity to adsorb oil [266].

Yi et al. developed nanofibrous materials through acrylic acid grafting onto pre-plasma-treated substrates [267]. The grafting process enhanced the hydrophilicity and surface functionality of the nanofibers, promoting strong interaction with oil molecules. They assessed the adsorbent in different oil-in-water mixtures and reported a kerosene flux of 6460 L m²/h with a corresponding separation efficiency in excess of 99.5%. In an earlier study, Li et al. reported a simple method remediating a kerosene–water mixture sing a silica-coated polyurethane sponge [268]. The material demonstrated high sorption capacities for kerosene and other hydrocarbons, highlighting the impact of surface functionalization in tailoring polymer behavior toward nonpolar pollutants. Specifically, the sponge was reported to have a kerosene adsorption capacity 55.8 times its own weight. After corrosion and heat treatment for 6 h, the sponge did not show diminished kerosene adsorption capacity. An interesting finding was the discovery that 0.32 g of the sponge could facilitate the continuous removal of 13 L of kerosene with corresponding high removal efficiency. This translated to a removal capacity of 32,000 times its own weight and the authors recommended that the SiO₂-PU-sponge could find application in the remediation of oil pollutants especially for oil-spill remediation. In a related study, Sabouri et al. synthesized a superhydrophobic and superoleophilic nanocomposite foam using polyurethane as the polymeric base and incorporating magnetic nanoparticles [269]. The magnetic nanocomposite not only facilitated rapid kerosene adsorption but also allowed easy retrieval from the aqueous medium via magnetic separation. The incorporation of MNPs resulted in a kerosene removal of 27.7 g/g, an 83% increase from 14.9 g/g obtained using the as-synthesized polyurethane foam. The material was reusable, although the authors reported that a thin oleophilic oil coat ensured that the performance of the recovered adsorbent was not as high as that of the pristine one. Further expanding polymer versatility, Dutta et al. investigated the oil adsorption behavior of chemically crosslinked poly(ethylene-co-vinyl acetate) (EVA) [270]. The cetyl–functionalized EVA exhibited excellent oil and kerosene adsorption capacity due to its enhanced oleophilic nature and networked structure, making it suitable for broader use in organic solvent and hydrocarbon removal systems. Specifically, EVAM1 prepared with the smallest amount of maleic anhydride (3 wt.% of EVA) was found to be the best of the suite of adsorbents prepared. The maximum adsorption capacity of this adsorbent for kerosene was found to be 390%. The SEM image further illustrated that the incorporation of CA and MA in EVAM1 facilitated the formation of a polymer network with expansion capabilities, which is essential for enhancing the adsorption of oils and organic solvents. As a result, it demonstrated superior adsorption performance compared to those synthesized with higher concentrations of MA and CA (EVAM2 and EVAM3).

4.2.5. Zeolites, Nanoclays, and Metal–Organic Frameworks

Advancements in nanomaterials have introduced zeolites, nanoclays, and metal–organic frameworks (MOFs) as promising candidates for hydrocarbon remediation [271,272,273]. These materials exhibit high surface area, tunable porosity, and selective surface functionalities, which make them suitable for adsorption and membrane-based kerosene separation [274]. This section critically reviews studies that investigated these materials and their modified forms for kerosene removal from wastewater.

Abbas and Al–Jubouri investigated the integration of 4A zeolite nanoparticles into polyethersulfone (PES) and cellulose acetate (CA) matrices to fabricate mixed–matrix microfiltration membranes for kerosene remediation [193]. Their results showed that 0.5 wt% zeolite incorporation significantly enhanced water permeability, oil rejection, and fouling resistance. Specifically, the membrane exhibited enhanced porosity (87.7%) and achieved a maximum pollutant rejection of 98.8%, a high pure water flux of 91.1 L/m² h, a relative flux reduction of 21.8%, a flux recovery ratio of 97.7%, and a pollutant permeation flux of 75.55 L/m²·h, which was approximately eight times that of the as–synthesized membrane. This highlights the role of zeolites in improving membrane flux and selectivity via increased pore connectivity and surface energy modifications. Reusability tests confirmed the robustness of the composite membranes and their effectiveness in treating wastewater. To improve zeolite wettability and selectivity, Liang et al. [273] reported the development of a 5A zeolite powder–based adsorbent for the separation of kerosene. The material exhibited superhydrophobic and superoleophilic properties, significantly enhancing its separation efficiency for oil–water mixtures [273]. Over 98% kerosene removal efficiency was recorded indicating that the prepared material offered a high adsorption efficiency. Notably, the material showed excellent recyclability, with its adsorption capacity maintained at 90% after four cycles. Similarly, Al–Jammal et al. applied a dealumination process to raw Jordanian zeolitic tuff to prepare zeolite-based adsorbents [275]. Adsorptive kerosene removal efficiency was obtained as 10.6% using raw zeolitic tuff (RZT). A much higher value of 42.7% was achieved when using acid treated zeolitic tuff (TZT) compared to the 34.1% obtained when micro–emulsified TZT was used. These modifications demonstrate the importance of surface engineering in tailoring zeolitic materials for kerosene capture in complex aqueous environments. The slightly lower kerosene removal efficiency achieved with the use of micro–emulsified TZT was attributed to the surface modification carried out. Nanoclays, due to their layered silicate structures and high aspect ratios, offer unique adsorption capabilities. Sharafimasooleh et al. studied the use of modified nanoclays for the adsorption of petroleum hydrocarbons (kerosene, gasoline and toluene) [271]. Their results showed that the modified nanoclay removed more kerosene compared to toluene and gasoline and performed better than the unmodified nanoclay. The modified nanoclay was able to remove kerosene five times its own weight (5 g/g) and this was reported to be a better performance compared to results available in the literature.

Metal–organic frameworks (MOFs), characterized by their high porosity, crystalline structure, and tunable surface chemistry, are increasingly being integrated into advanced water purification systems [274]. Chen and Jiang [272] fabricated a nanofiber composite membrane using polyacrylonitrile (PAN) and UiO–66–NH₂ MOF particles. The introduction of MOFs significantly increased the kerosene adsorption performance of the membrane, which was attributed to the MOF’s high surface area and functionalized amino groups facilitating strong interactions with hydrocarbon molecules. Specifically, the 10%PAN–5%MOFs–coated adsorbent was reported to perform best with a kerosene removal capacity of 21.9 g/g which was higher than the approximately 12 g/g obtained with the pristine PAN adsorbents. The higher kerosene adsorption recorded for the 10%PAN–5%MOFs–coated adsorbent was linked the MOFs’ 3D structure which imparted a higher interface area to the adsorbent. Wang et al. [276] reported the synthesis of MOF@Cu(OH)₂@Cu membranes through an ultrafast method. They demonstrated the application of MOF–functionalized membranes by integrating superwetting MOF layers into separation substrates. These systems showed exceptional hydrocarbon removal efficiency, indicating the utility of MOFs in achieving selective wettability and robust separation.

Two main methods for removing kerosene are evident, the first is adsorption, where kerosene molecules either adhere to the material’s surface or become trapped within its pores, while the second is membrane separation, where materials act as barriers with controlled wettability to selectively block kerosene while allowing water to pass. The effectiveness of these methods depends of surface area, wettability, and pore structure. Functional modifications, such as acid treatments, grafting with organic groups, and polymer integration, are commonly used to enhance these properties. Additionally, research using natural precursors offers opportunities for sustainable and cost-effective applications, especially in decentralized treatment settings. Zeolites, nanoclays, and MPFs represent adaptable, modifiable platforms with significant potential for kerosene removal.

4.3. Surface Modification and Functionalization for Kerosene Affinity

Surface modification are key strategies to tailor nanomaterials for enhanced kerosene affinity and overall adsorption performance in complex aqueous environments. Surface modification refers to the alteration of the outermost layer of a nanomaterial to improve its physical structure, chemical reactivity, and interaction with target pollutants, while retaining its bulk properties [277]. Surface characteristics largely dictate their adsorption behavior because of their surface/volume ratio [278]. Modifying the surface enables the incorporation of desired functional groups, manipulation of surface energy, and improvement of interaction mechanisms with hydrophobic pollutants such as kerosene [279]. This modification enhances adsorption capacity, selectivity, stability, and introduces additional functionalities such as magnetism, responsiveness to stimuli, and reusability [272].

A range of surface–modified nanomaterials have been specifically investigated to improve kerosene removal. Akhavan et al. investigated the surface modification of silica nanoparticles using plasma polymerized 1,7–octadiene to yield a material with hydrophobic and oleophilic properties (ppOD) [251]. The ppOD was very efficient in adsorbing kerosene with a reported efficiency of 99.5% after 30 s of adsorption. Their results revealed the morphology of used ppOD to exhibit a high level of agglomeration which was not evident in the unmodified particles. In another study, Li et al. investigated the modification of polyurethane (PU) cubes by grafting with lauryl methacrylate (LMA) (PU–g–LMA) [280]. The SEM images showed the even distribution of the grafted polymer on the surface of the prepared nanomaterial [280]. PU–g–LMA showed superior performance in absorbing kerosene by as much as 27% compared with blank PU cubes. PU–g–LMA showed an actual kerosene removal of 41.42 g/g indicating its potential application for oil cleanup.

The modification of MWCNTs has been extensively reported with the aim of increasing their adsorption efficiency in the separation of kerosene from water. In one such study, Abdullah et al. reported the functionalization of MWCNTs [21]. They prepared a suite of modified MWCNTs-based nanoadsorbents using different modification agents. Specifically, surface modification of MWCNTs was done via Fe₃O₄ nanoparticle deposition to prepare Fe–MWCNTs [21]. This was then further modified with polyethylene (PE) to prepare PE/Fe–MWCNTs nanoadsorbent. Successful modification was confirmed using SEM images. Performance evaluation of the adsorbents showed that the adsorption capacity of PE/Fe–MWCNTs nanocomposite for kerosene was 3560 mg/g (removal efficiency = 71.2%), surpassing the performance of Fe–MWCNTs, ox–MWCNTs, and pristine MWCNTs. The adsorption isotherm and kinetics fitted well to the Langmuir isotherm and pseudo-second-order kinetic models. In other similar studies, MWCNTs were functionalized using metal oxides, as seen in the case of CeO₂, V₂O₅, and V₂O₅:CeO₂ nanocomposites [255]. The V₂O₅:CeO₂ nanocomposites were reported to have better performance (85% kerosene removal efficiency) compared to the individual materials. Also, TiO₂/MWCNTs achieved a high kerosene removal efficiency, reaching up to 84%, which was higher than that obtained using the as-prepared MWCNTs (40%), thereby validating the role of surface-bound metal oxides in improving adsorption kinetics and selectivity through hydrogen bonding and increased surface reactivity [151].

In addition to CNTs, surface modification strategies have been applied to silica and polymer–based adsorbents. In this context, the decoration of adsorbent materials with silica nanoparticles for enhanced functionality has gained some attention. Wang et al. reported the preparation of nanosilica/alkali–treated natural zeolite coated [252]. The study revealed that natural zeolite, subjected to alkali treatment and characterized by a high Al₂O₃/SiO₂ ratio alongside a high concentration of hydroxyl groups, showed significant ion exchange and hydrophilic properties. The material achieved a high–water separation efficiency of 99.4% for kerosene. Additionally, it displayed excellent recyclability, maintaining 98.3% efficiency for kerosene after 40 cycles. The preparation of polysulfone (PSF) was reported by Obaid et al. [247]. PSF was modified with the introduction of rice husk–derived silica nanoparticles and evaluated for the separation of petroleum fractions from water. The addition of SiO₂ nanoparticles significantly increased the flux. For kerosene/water, the daily flux was 115 m³/m² for SiO₂–doped PSF nanofiber membrane while the Young’s modulus was improved. This demonstrates how surface functionalization can simultaneously boost adsorption efficiency and structural integrity. Same observation was reported by Li et al. [268] who noted that hydrophobic SiO₂ coated polyurethane sponges could adsorb kerosene 55.8 times its own weight indicating excellent adsorptive capacity. These results confirm that nanoscale surface engineering is a powerful strategy to increase the oleophilicity and reusability of adsorbents while maintaining operational simplicity.

Surface modification and functionalization of nanomaterials are essential in transforming them into highly efficient adsorbents for kerosene. As illustrated in

Table 9. Summary of some surface–modified and functionalized nanomaterials for kerosene adsorption.

Material	Surface Modification Approach	Kerosene Removal Performance	Functionality	Reference
PE/Fe–MWCNTs	Fe3O4 deposition + polyethylene coating	3560 mg/g, 71.2% efficiency	Synergistic magnetic and polymeric effects	[21]
PU–g–LMA	Grafting with lauryl methacrylate	41.42 g/g (27% over unmodified PU)	Improved surface wettability for hydrocarbons	[280]
ppOD–silica	Plasma polymerized 1,7-octadiene coating	99.5% in 30 s	Enhanced hydrophobicity and oleophilicity	[251]
V2O5:CeO2/MWCNTs	Metal oxide hydrothermal doping	85% removal efficiency	Increased surface sites and polar interactions	[255]
Nanosilica/zeolite fabric	Silica-coated, alkali-treated natural zeolite	99.4% separation, 98.3% after 40 cycles	Superoleophobicity, high durability	[252]
TiO2/MWCNTs	TiO2 deposition	84% efficiency (vs. 40% unmodified)	Hydrogen bonding, enhanced reactivity	[151]
SiO2–PU sponge	SiO2 nanoparticle coating	55.8 g/g adsorption capacity	Increased oleophilicity and reusability	[268]

, these modifications lead to significant improvements in adsorption capacity, selectivity, and reusability through the incorporation of functional groups, adjustment of surface energy, and promotion of strong interactions. If unmodified materials, which frequently exhibit limited affinity and effectiveness, the functionalized adsorbents demonstrate more robust and precise interactions with pollutants. These strategies also facilitate multifunctionality, such as magnetic recovery and mechanical durability, offering practical advantages for scalable and sustainable application in real wastewater treatment and oil spill scenarios.

5. Challenges and Future Perspectives

Treatment of kerosene from wastewater is tough since kerosene is hydrophobic, water insoluble, and has a complicated chemical structure, the opposite of typical treatment. Recent methods for the remediation process consist in creation of new materials, i.e., functionalized adsorbents, nanocomposites, and membrane technology, which exhibit a greater surface area, selective adsorption, and efficiency in the process of separation. However, fouling, regeneration limitation, and such production costs of these new materials remain the predominant difficulties to their widespread application. New material design principles aim to achieve surface chemistry with a hydrophobic–oleophilic function, utilizing low–cost or bio–based materials to enhance sustainability and performance. Furthermore, the integration of these materials with technologies such as photocatalysis, electrochemical treatment, or hybrid filtration systems also gains more significance due to their synergistic effects. Despite such developments, field–level application is hindered by environmental heterogeneity, scalability, and secondary contamination. Interdisciplinary research by material science, environmental engineering, and life–cycle analysis is called for the development of cost–effective, efficient, and environmentally friendly technologies for kerosene treatment, particularly industrial waste oil–contaminated and spill–contaminated water bodies.

In the future, creating new highly selective and reusable multifunctional materials, e.g., engineered nanomaterials, bio–based composites, and stimulus–responsive materials. Their integration into hybrid systems—wherein adsorption, photocatalysis, and membrane filtration would be coupled—can potentially optimize removal efficiency and make continuous treatment possible. Application of artificial intelligence and machine learning to process minimization, material selection, and real–time monitoring can also be used to revolutionize kerosene remediation technologies. Cost–effectiveness and scalability in green synthesis of adsorbents and catalysts are also prominent factors in reducing the cost of the treatment process as well as the environmental footprint.

In addition to a technical assessment, removing kerosene from wastewater must be evaluated from an integrated perspective that integrates life-cycle assessment (LCA) and cost considerations, operational and regulatory issues, and tradeoffs of water, energy and materials. The Life-Cycle Assessment (LCA) approach provides an exhaustive viewpoint on environmental effects with all aspects involved: from the extraction and production of raw materials to treatment processes and sludge disposal—& allows for comparison among alternatives (biodegradation, adsorption, advanced oxidation) with respect to their global warming potential (GWP), ecotoxicity, and resource depletion. In addition to environmental concerns, economic considerations must also be evaluated to determine the techno-environmental feasibility of removing kerosene from wastewater: Capital expenditures (CAPEX) for the reactor installation, OPEX (operational expenditures), including energy, chemicals and labor, and disposal costs are key factors; for example, biological treatment systems may have lower OPEX but require greater volume and time to retain, while advanced oxidative processes have higher energy and chemical costs and provide rapid degradation.

The selection of treatment processes is further complicated by operational conditions such as changing amounts of kerosene, other substances present in addition to kerosene, temperature sensitivities and microbial inhibition, as well as by regulatory constraints such as the maximum allowable limits for total petroleum hydrocarbons set by regulatory agencies (e.g., the US EPA, GCC, or European Union). Therefore, the decision making process must also take into consideration the trade-offs inherent in the water-energy-materials nexus; for example, processes that are energy-intensive and reduce water contaminants may increase carbon emissions, while adsorbent materials made from non-renewable resources may transfer the burden of environmental impact from down-stream to up-stream, and recovery techniques that use solvents to optimize retrieval of kerosene may generate additional waste materials. Achieving sustainability with treated effluent(s) requires that the treatment solution addresses the intersection of environmental stewardship, economic viability, regulatory compliance and resource efficiency as a balanced system using techno-economic and LCA models for the purpose of developing scalable, resilient and circular solutions.

Another key area to explore in the future is designing treatment processes to treat difficult wastewater matrices that contain a mix of organic and inorganic contaminants. Environmental regulations and standards will keep evolving, and innovations in detection methods and treatment processes will become even more essential.

The removal of kerosene remains a significant challenge across industrial, environmental, and emergency-response contexts. Analyzing Technology Readiness Levels (TRLs), presented in

Table 10. Summary of Technology Readiness Levels for kerosene removal.

Technology/Method	Description	Typical TRL	Limitations
Flocculation/coagulation	Coagulants destabilize the droplets by: neutralizing surface charges—promoting agglomeration—increasing droplet size for separation	TRL 3–5	Depend of specific process and whether it has been tested at pilot scale.
Bioremediation (Microbial Degradation)	Microorganisms degrade hydrocarbons.	TRL 6–8	Effective for low concentrations; slower and depends on environment.
Granular Activated Carbon (GAC)	Adsorption of dissolved and residual hydrocarbons.	TRL 9	Standard polishing step; requires regeneration/replacement.
Polymeric or Oleophilic Sorbents	Sponges selective	TRL 9	High sorption capacity.
Zeolites	Used in industrial adsorption, refinery operations, and hydrocarbon separation.	TRL 6–7	Fouling by organics, competition with other nonpolar contaminants, regeneration energy cost.
Nanoclays (e.g., bentonite, organoclays)	Effective for kerosene due to hydrophobic organophilic modifications.	TRL 4–6	Low mechanical strength in continuous systems, regeneration is often impractical.
Metal–Organic Frameworks (MOFs)	High tunability and surface area make them highly promising.	TRL 3–4	Stability issues in water for MOFs, high cost of synthesis and regeneration challenges.
Membrane Filtration (UF/NF/RO)	Physical separation via selective membranes.	TRL 7–9	Fouling is major challenge.
Photocatalysis	TiO2, ZnO, Fe-doped catalysts, etc.	TRL: 4–5	Dezactivation, adsorption onto surface, light penetration issues and high energy demand.
Advanced Oxidation (O3, UV/H2O2, Fenton)	Oxidizes hydrocarbons into simpler compounds.	TRL 6–8	Effective for dissolved organics; energy-intensive.
Magnetic Nanoparticle Sorbents	Magnetic particles coated with oleophilic materials.	TRL 3–5	Promising research; limited commercial deployment.
Bio-based Superhydrophobic Materials	Specialized filters/sponges that selectively absorb.	TRL 3–6	Rapidly growing field; not widely commercial yet.

, can be see those technologies such as zeolites, nanoclays, metal–organic frameworks (MOFs), photocatalysis, and advanced membranes have demonstrated promising potential at laboratory and bench scale.

It is clear that to ensure from academic concepts to operational solutions, continued, coordinated research efforts are essential. For these goals are necessary: more pilot-scale to validate performance under real conditions; optimization of stability and regeneration (nanoclays and MOFs), witch exhibit degradation; create hybrid processes that compensate for each individual technology’s limitations; economic and life-cycle assessments, to transition from research novelty to viable commercial products; material innovation, including surface functionalization, composite formation, and structural stabilization to improve sorption capacity and resistance to fouling, toxicity, and variable organic loading.

From sustainable point of view the kerosene treatment technologies must be focused on minimize environmental impact, reduce energy consumption, and avoid generating secondary pollution. The sustainable approaches prioritize low-energy processes such as biodegradation, adsorption using natural or reusable materials, and membrane sys-tems designed for durability and minimal chemical use. Mentioned technologies have low greenhouse gas emissions and not formation the toxic by-products. Economically, sustainable kerosene removal means cost-effective materials, scalable treatment systems, and technologies with low operational demands. The socially sustainable solutions aim to assure safety water resources, and minimizing exposure to volatile hydro-carbons and hazardous sludge. Overall, sustainability in kerosene treatment requires balancing environmental performance and accessibility, while proposing technologies that are robust, regenerable, and capable of delivering clean water.

Removing kerosene from wastewater is done using different techniques combining chemical and physical processes (

Table 11. Individual processes for kerosene removal.

Process	Typical Efficiency (%)	Key Process Parameters	Cost ($/m3)	Toxicity Level and Reduction
Adsorption (Activated Carbon, CMC Composites)	80–98%	pH 5–8, adsorbent dose 1–10 g/L, contact time 10–120 min	0.5–3.5	TU reduced by 40–70% due to removal of dissolved hydrocarbons
Dissolved Air Flotation (DAF)	60–90% (free/dispersed oil)	Pressure 4–6 bar, coagulant 20–80 mg/L	0.3–1.0	Moderate toxicity reduction (20–40%), limited for emulsified oil
Coagulation–Flocculation	70–95%	Coagulant dose 50–200 mg/L, pH 6–8, rapid/slow mixing	0.2–1.5	TU reduced by 30–60% due to removal of emulsified droplets
Membrane Filtration (UF/NF)	90–99%	Pressure 2–10 bar, crossflow velocity, pretreatment required	1.5–6.0	High toxicity reduction (50–80%) but depends on dissolved vs. free oil
Advanced Oxidation Processes (AOPs)	60–95% degradation	H2O2/Fe2+ dose, UV intensity, ozone flow rate	2–10	Significant reduction in LC50/EC50 toxicity (40–80%) due to molecular oxidation

), which can be done in different ways, which results in different efficiency levels and costs associated with process operation. One of the most effective techniques for the removal of kerosene from wastewater is by using adsorbents, such as activated carbon or modified biopolymers, which can remove anywhere between 80 and 98% of the kerosene from the wastewater, depending on the dosage, contact time with the adsorbent and the pH level, with moderate reduction in toxicity to aquatic organisms due to the elimination of dissolved hydrocarbons. Dissolved air flotation (DAF) removes free and dispersed kerosene droplets (60–90%) by attaching air bubbles to the kerosene droplets under optimized pressures and added coagulants, while limited emissions of emulsified fractions are removed. Coagulation-flocculation of emulsified kerosene using expanded polymeric coagulants, PAC, or alum has been found to reach efficiencies of 70–95%, especially when mixing intensity and pH are strictly controlled. Membrane filtration methods, including ultrafiltration (UF) and nanofiltration (NF), have shown >95% removal efficiency for emulsified oil-water, but this comes with challenges of membrane fouling and high operational costs. Advanced oxidation processes (AOP) such as Fenton, photocatalysis, ozonation, and the like have been shown to effectively degrade dissolved hydrocarbons to varying degrees and can reduce the toxicity of these hydrocarbons by approximately 40–80%; however, cost of reagents, and energy requirements may be limiting. Each of these methods provides certain advantages, while others show varying performance to kerosene concentration, droplet size distribution, salinity, and surfactants present in the wastewater, therefore costs, energy consumption, and toxicity must all be considered when choosing the appropriate method.

Finally, an interface between material scientists, environmental engineers, and policymakers at the cross-disciplinary level will be essential to fill the gap from laboratory-scale technology to useful, scalable technology. In summary, despite the diversity of problems that exist today, visionaries of future development founded on material innovation, technological integration, and data-optimized optimization provide a clear direction for sustainable and effective kerosene removal from wastewater to clean water systems and enhanced environmental safety.

6. Conclusions

The regular contamination of water bodies with kerosene becomes a severe environmental and public health problem, and the employment of efficient, green, and high-capacity treatment processes is therefore greatly needed. The latest status of trends in kerosene removal from wastewater has been briefly discussed in this review, mentioning the advantages and limitations of conventional methods such as physical separation, chemical oxidation, and biodegradation. Prioritization was placed on new development in material synthesis (new adsorbents, nanomaterials, and photocatalysts); to enhance performance in removal efficiency, selectivity, and reusability. In addition, hybrid systems between these new materials, e.g., membrane filtration and photocatalytic reactors, offer synergies and alleviate root-of-the-problem operation problems. Despite all these advancements, some of the most important concerns remain material regeneration, treatment of advanced wastewater matrices, and cost feasibility at an industrial level. Interdisciplinarity between environmental engineering, materials science, and digital technologies, including artificial intelligence and machine learning, will drive kerosene remediation innovation in the near future. Low-cost and sustainable materials, optimization of system configuration, and compliance with regulations will be some of the future areas of emphasis. Finally, there will be a requirement to upgrade the material-based treatment processes and develop composite solutions to attain environmental sustainability in the long term and successful conservation of water resources from hydrocarbon contamination.