A Review of Materials for the Removal of Micro- and Nanoplastics from Different Environments

Abstract

Microplastics (MPs) and nanoplastics (NPs) have emerged as persistent environmental pollutants, posing significant ecological and human health risks. Their widespread presence in aquatic, terrestrial, and atmospheric ecosystems necessitates effective removal strategies. Traditional removal methods, including filtration, coagulation, and sedimentation, have demonstrated efficacy for larger MPs but struggle with nanoscale plastics. Advanced techniques, such as adsorption, membrane filtration, photocatalysis, and electrochemical methods, have shown promising results, yet challenges remain in scalability, cost-effectiveness, and environmental impact. Emerging approaches, including functionalized magnetic nanoparticles, AI-driven detection, and laser-based remediation, present innovative solutions for tackling MP and NP contamination. This review provides a comprehensive analysis of current and emerging strategies, evaluating their efficiency, limitations, and future prospects. By identifying key research gaps, this study aims to guide advancements in sustainable and scalable microplastic removal technologies, essential for mitigating their environmental and health implications.

1. Introduction

Microplastics (MPs) and nanoplastics (NPs) are small plastic particles that have become ubiquitous in various ecosystems, posing growing concerns due to their environmental and health risks [1]. MPs are typically defined as plastic particles smaller than 5 mm, while NPs measure less than 1 µm in size [2]. These particles originate primarily from the breakdown of larger plastic debris and are introduced into the environment through various sources, including improper waste disposal, industrial activities, and everyday products like cosmetics, textiles, and packaging. Once released, MPs and NPs are difficult to contain because of their small size and persistent nature, allowing them to disperse easily through water, air, and soil. Consequently, they have been detected in environments ranging from oceans and rivers to the atmosphere, highlighting their far-reaching impact [3].

The increasing prevalence of M/NPs has raised the alarm among scientists and environmentalists due to their significant ecological impact and potential threats to human health. Research has demonstrated that these particles can be found in drinking water, food products, and even in human blood and placentas, sparking concern about their infiltration into vital biological systems [4,5]. The risks associated with M/NPs are further compounded by their ability to adsorb hazardous substances such as heavy metals, persistent organic pollutants (POPs), and pharmaceutical residues, which can enhance their toxicity and lead to adverse environmental and health effects. When ingested by aquatic organisms, such as fish and mollusks, M/NPs can accumulate in their tissues, eventually entering the food chain. This bioaccumulation poses a threat to biodiversity, disrupts marine ecosystems, and has potential implications for human food security, as seafood contaminated with MPs/NPs becomes a health risk [6].

To mitigate the growing threat of M/NP pollution, various technologies have been developed for removing these particles from the environment. Among the most widely used methods are traditional filtration, coagulation, and sedimentation processes, which are commonly employed in wastewater treatment plants (WWTPs) [3]. While effective for larger particles, these systems often struggle to remove smaller particles like NPs due to their colloidal properties and small size. Additionally, traditional treatment methods are limited in their ability to address the widespread contamination of open water bodies such as oceans and rivers, where decentralized and large-scale removal systems are needed [3].

In recent years, adsorption-based techniques have gained attention as promising alternatives for M/NP removal. Materials like activated carbon, clay minerals, and biochar have been shown to effectively absorb MPs and NPs due to their high surface area and binding capacity [7,8]. These materials offer advantages such as cost-effectiveness and ease of application. However, adsorption techniques still face limitations in terms of selectivity for different types of plastic particles, regeneration capacity, and the challenge of scaling up for industrial use. Despite these drawbacks, ongoing research is focused on enhancing the adsorption properties of these materials to improve their efficiency in various environmental contexts [7]. Another promising approach for M/NP removal is membrane filtration, which utilizes ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) membranes. These membranes are designed with small pore sizes capable of trapping plastic particles, including NPs, making them highly effective for M/NP removal in water treatment processes [9,10]. However, membrane technologies come with their own set of challenges, including susceptibility to fouling, which can reduce their efficiency over time, and high operational costs. The maintenance and replacement of membranes can become expensive, making this method less feasible for large-scale applications, particularly in developing regions with limited resources [3].

This review presents a comprehensive and novel synthesis of the current materials and techniques developed to address the pervasive challenge of removing microplastics and nanoplastics (M/NPs) from diverse environmental matrices, including water, soil, and air, by weaving together emerging interdisciplinary approaches drawn from environmental science, materials engineering, and nanotechnology. Unlike previous reviews, it critically evaluates not only the advantages—such as high removal efficiencies or cost-effectiveness—but also the persistent limitations, such as operational constraints and environmental adaptability, of a wide array of methods. These methods range from conventional technologies like filtration, coagulation, and adsorption, which rely on readily available materials such as activated carbon and biochar, to cutting-edge innovations like ultrafiltration, nanofiltration, and reverse osmosis membrane systems, which leverage precise pore-size engineering to capture even nanoscale particles. The analysis systematically assesses their performance across varied environmental contexts, from wastewater treatment plants to open oceanic systems, while explicitly identifying critical research gaps that hinder progress in this field. These gaps include the limited scalability of advanced removal systems, which often remain confined to laboratory or small-scale applications; the absence of standardized, universally accepted methods for detecting and quantifying nanoplastics, complicating comparative studies and regulatory efforts, and a notable scarcity of research addressing M/NP remediation in air and soil environments, which lag significantly behind the more extensively studied aquatic systems [1,2]. Furthermore, this study delves into future directions and emerging trends in M/NP removal technologies, spotlighting the urgent need for innovations that enhance efficiency, reduce operational costs, and achieve scalability to tackle the global scope of plastic pollution. It explores promising avenues, such as the development of bioinspired materials, hybrid adsorption-membrane systems, and decentralized treatment approaches tailored to resource-limited settings. By not only consolidating and synthesizing existing methodologies but also proposing a forward-looking framework that prioritizes scalable, multi-matrix solutions capable of addressing M/NPs across water, soil, and air simultaneously, this review significantly advances existing knowledge. This stands in contrast to prior studies, which have predominantly adopted a narrower lens, focusing either on specific techniques like adsorption or filtration or on singular environmental compartments such as marine ecosystems, without offering a holistic, integrative perspective [3,10]. Through this broader and more integrative approach, the review not only bridges disciplinary silos but also lays the groundwork for practical, real-world applications by identifying actionable research priorities. Ultimately, it seeks to arouse increased attention, funding, and collaborative research efforts toward innovative, sustainable strategies that mitigate the escalating environmental and health risks posed by M/NP pollution, thereby contributing to both scientific advancement and global environmental policy.

2. Materials Used for Removal of Micro- and Nanoplastics

2.1. Conventional and Novel Techniques for MP/NP Removal

The removal of micro- and nanoplastics (MPs and NPs) is governed by several key mechanisms, which are fundamental to most technologies discussed in this review.

Adsorption—Adsorption is a well-established method that relies on electrostatic, hydrophobic, and Van der Waals interactions between MPs/NPs and the surface of the adsorbent. Activated carbon and biochar are commonly used due to their high porosity and surface functionality, which enhances their affinity for plastic particles [11,12]. Surface modifications of these adsorbents are also being explored to further improve selectivity and capacity.

Filtration—Filtration works through physical sieving, inertial impaction, or electrostatic repulsion, depending on the filter media. Membrane-based systems, especially those employing nanofiber membranes or electrospun materials, provide high efficiency and scalability. Functionalized membranes with surface charges or catalytic properties are a growing area of interest [13].

Degradation (Photocatalysis)—Photocatalytic degradation employs semiconductors like TiO₂ or ZnO to generate reactive oxygen species (ROS) under light irradiation, breaking down polymer chains into smaller or mineralized products. Recent innovations include doping with metals or forming heterojunctions to enhance photocatalytic efficiency under visible light [2].

Magnetic Separation—Functionalized magnetic nanoparticles (e.g., Fe₃O₄) are designed to bind MPs/NPs through surface functional groups (e.g., -COOH, -NH₂), enabling magnetic recovery. Novel developments include hybrid magnetic composites that combine adsorption, catalytic, and magnetic properties in a single platform [14].

Electrocoagulation—This process uses electric current to release metal ions from electrodes, which act as coagulants to destabilize and flocculate MPs/NPs. Its simplicity and adaptability make it attractive for large-scale water treatment. Coupling electrocoagulation with filtration or oxidation is being investigated for enhanced performance [15].

Bio-based Flocculants and Bioremediation—Researchers are exploring natural flocculants derived from alginate, chitosan, or plant extracts to reduce chemical usage and improve biodegradability. Additionally, certain bacteria and fungi show the ability to degrade plastic polymers, presenting a sustainable solution [16].

Plasmonic Photocatalysis—Incorporating noble metal nanoparticles (e.g., Ag, Au) into photocatalytic systems enhances light absorption via localized surface plasmon resonance (LSPR), thereby improving MP/NP degradation efficiency under visible light [17].

Electrokinetic Separation—Based on electrophoresis and dielectrophoresis, this technique manipulates plastic particles in microfluidic systems using electric fields. It offers precise control and sorting of MPs/NPs based on size and surface charge, with applications in analytical separation and detection [18].

AI-Integrated Systems for Detection and Removal—Emerging systems are integrating artificial intelligence with sensor arrays (e.g., optical or electrochemical) to detect, classify, and selectively remove MPs/NPs in real time. These smart platforms are in early development stages but show potential for automated environmental monitoring [19]. These mechanisms are often used in combination to improve efficiency, and their suitability depends on factors like particle size, matrix complexity, and cost-effectiveness.

2.2. Biological Method/Bioinspired Based Materials

Biological-based methods offer several advantages for technologies that remediate water and soil environments. The use of biological processes to treat pollutants in the environment has the advantages of low operating costs, high energy efficiency, simple processes, and, most importantly, no secondary pollution. The use of biological methods for the degradation of micro- and nanoplastic pollutants has emerged as a key area of development. These approaches include hydrolysis, microbial digestion of plastics, and the adsorption or entrapment of microplastics within the microchannels of microalgae.

Biological methods can effectively degrade and mineralize micro- and nanoplastics (M/NPs), but they require a prolonged period to achieve optimal removal results. Biomaterials, which originate from biological sources or are inspired by biological systems, offer a promising alternative for the removal of microplastics (MPs) and nanoplastics (NPs). They emphasize properties such as biodegradability, renewability, and low environmental impact. In contrast to synthetic sorbents and mechanical filtration methods—which may lead to secondary pollution or require high energy input—biomaterials provide an environmentally friendly approach that aligns with natural ecological processes. Recent research has explored the use of various biomaterials for reducing MPs and NPs in different environmental settings. Advanced filtration, dynamic membranes, and adsorption on green algae are among some of the physical removal techniques that have been studied [20,21]. The sorption of fluorescent polystyrene microplastic particles on Fucus vesiculosus seaweed was examined in a study by Sundbaek et al. [22]. With a high adhesion efficiency of roughly 94.5%, the researchers hypothesized that “trapping” of the microplastics inside the microalgae’s microchannels dominated the sorption mechanism. Due to the physiological and topographical heterogeneities in the seaweed structure, spatial differences in the microplastics’ adhesion patterns to the algal surface were observed. The adsorption of polystyrene microplastics by three-dimensional reduced graphene oxide (3-D RGO) sheets was recently investigated and modeled by Yuan et al. [23]. The diffusion of the microspheres in a spontaneous endothermic adsorption process was aided by the suggested 3-D structure, which prevented the sheets from clumping together in the micro-polluted environment (Figure 1). It was determined that the 3-D RGO maximum adsorption capacity was significantly affected by the pH of the solution, temperature, and the starting concentration of ions and micropollutants in the solution. The maximum observed absorbability was 617.28 mg/g for a contact duration of 120 min at 26 °C, 6 pH, and an initial concentration of 600 mg/L. The group claims that the strong π–π interactions between the 3-D RGO carbon ring and the benzene ring of polystyrene dominated the adsorption mechanism. These conclusions were further confirmed by fitting the experimental data into a pseudo-second-order kinetic model and Langmuir’s adsorption isotherm, which confirms intraparticle diffusion in a monolayer adsorption process [24].

2.3. Activated Carbon, Biochar, and Polymeric Adsorbents

Carbon-based adsorbents such as graphene, graphene oxide (GO), activated carbon (AC), biochar (BC), carbon nanotubes (CNTs), metal-modified carbon materials, and fly ash have attracted considerable attention due to their unique structural features. These properties enhance their effectiveness in removing microplastics and nanoplastics (MPs/NPs) from water. A major factor behind their performance is the ability to modify their surface characteristics to suit specific applications. Among them, activated carbon is the most widely used in wastewater treatment, offering flexibility in the development of various adsorbent types for different environmental purposes, including the removal of MPs and NPs from aqueous systems [25]. Due to the relatively high production cost of coal-derived activated carbon, biochar presents a more economical option with effective adsorption capabilities for microplastics and nanoplastics (MPs/NPs) [11]. Biochar can be produced from a wide range of woody biomass sources, including agricultural residues such as peanut shells and dairy manure. The interaction between carbon-based adsorbents and MPs/NPs is complex and depends on several factors, including the surface chemistry and structure of the carbon material, the ionic composition of the water, and the properties of the adsorbates. The adsorption mechanisms involved include hydrophobic interactions, hydrogen bonding, van der Waals forces, electrostatic interactions, π–π stacking, pore filling, and intraparticle diffusion [26,27]. The impact of these mechanisms on adsorption varies greatly, depending on the MPs’/NPs’ properties and the adsorbent type.

Nisha et al. used iron-modified biochar loaded with nanoparticles to easily remove NPs/MPs. Including iron species, particularly Fe₃O₄, in the biochar creates active sites for surface complexation with nanoparticles, which enhances its adsorption capacity. Iron-modified biochar has shown high efficiency in removing nanoplastics (NPs) from water, achieving complete removal in under 10 min and maintaining its performance over four reuse cycles [28]. Likewise, biochar modified with magnesium and zinc enhances the adsorption of polystyrene (PS) microplastics through the presence of positively charged Mg(OH)₂ and ZnO. This enhancement is mainly attributed to electrostatic interactions and the formation of PS–O–metal bonds. In addition to its adsorption capabilities, Mg/Zn-modified biochar possesses catalytically active sites that support hydrogenation reactions. These catalytic properties are especially useful during thermal treatment, promoting the breakdown of PS microplastics into smaller molecular compounds. This combined adsorption and catalytic function contributes not only to efficient MP removal but also to the degradation and potential reuse of plastic materials [11]. Ganie et al. observed that biochar produced via pyrolysis at 750 °C exhibited a positive surface charge of 2.85 mV. When this biochar was combined with negatively charged PS-based MPs/NPs (−39.8 mV), the zeta potential of the mixture swiftly shifted to −9 mV, indicating a substantial electrostatic attraction between the materials [12].

Lina et.al used granular activated carbon (GAC) to remove the polystyrene nanoparticles from drinking water. It was found that the adsorption and removal of PS nanoplastics are mainly due to electrostatic interactions between the positively charged nanoplastics and negatively charged GAC. The results revealed that the adsorption capacity increased with the nanoplastic concentration, and a maximum adsorption capacity of 2.20 mg/g was observed (Figure 2) [25].

In a similar study, activated carbon modified with ZnCl₂ with enhanced surface area, pore size, and pore volume was prepared as an activator and used for the adsorption of PSNPs. The maximum absorption capacity of the tap and lake water tests was recorded at 2.450 mg/g and 1.323 mg/g, respectively. The absorption capacity of the lake water test was significantly different from that of tap water and pure water [12].

2.4. Functionalized Magnetic Nanoparticles

Magnetic separation has recently attracted growing interest as a fast and low-cost approach for removing microplastics (MPs), leading to the development of various magnetic materials. This method relies on the hydrophobic nature of MPs, which enables their interaction and attachment to magnetic particles. Once magnetized, the movement of MPs can be directed using magnets or an external magnetic field, facilitating their separation from wastewater [29]. Consequently, the most widely used plastics—including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyamide (PA), polyvinyl chloride (PVC), and polystyrene (PS)—can be collected using magnetic materials. The magnetic separation of microplastics typically involves two main steps: (1) attachment of magnetic nanoparticles (NPs) to the MPs for magnetization, and (2) movement of the magnetized particles under the influence of an external magnetic field for removal. A magnetic field could drive microrobots to capture plastic particles by firmly adhering MNPs to them, or a magnetic field would allow them to adhere to plastic particles. An external magnetic field enables magnetic nanoparticles (MNPs) to move in a controlled direction and interact with microplastics (MPs) present in water [13]. In addition, functionalized and catalytic magnetic nanostructures have the capability not only to capture and transport MPs but also to degrade them when exposed to light and a magnetic field [30]. The high specific surface area and hydrophobic properties of magnetic nanoparticles (MNPs) enable them to adsorb plastic microparticles or fragments through electrostatic interactions. However, this physical adsorption process can be hindered by the diverse affinities of pollutants in water. To address this limitation, surface modification techniques have been employed to enhance the adsorption efficiency, creating a more effective mechanism for pollutant capture. For instance, Zhang et al. developed magnetic Fe₃O₄@alkali-treated coal fly ash composites for effective adsorption and magnetic removal of heavy metals, showcasing the broader applicability of such materials. Similar approaches have been extended to MPs and NPs, highlighting the role of magnetic surfaces in environmental remediation [29].

However, very few studies confirm the applicability of magnetic nanoparticles to capture microplastics. In the study by Grbic et al., magnetic Fe nanoparticles were functionalized with silane, producing hydrophobic nanoparticles. MPs of >20 μm and >1000 μm were recovered from seawater by more than 92%, while MPs of 200–1000 μm were recovered from freshwater and sediment, respectively, by 78% and 84% [31]. In another study by Misra et al., microemulsion iron oxide/silica particles were synthesized and coated with an ionic liquid; 100% removal of 0.1 and 1.0 mm polystyrene beads was observed within 24 h of contact. For polyethylene, polypropylene, polystyrene, and polyethylene microplastic capture by Fe₃O₄ nanoparticles, Shi et al. measured average removal percentages of 87%, 85%, 86%, and 63%, respectively (Figure 3) [32]. Daniel et al. synthesized magnetite nanoparticles using two distinct methods: hydrothermal coprecipitation and solvothermal decomposition. For the thermal decomposition route, the surface of the synthesized magnetic nanoparticles was further functionalized with primary and secondary amino groups via alkoxysilane treatment to examine the influence of electrostatic interactions on particle performance. The results revealed that the presence of varied polar functional groups on the nanoparticle surfaces promotes interaction with microplastics (MPs) through electrostatic attractions and molecular forces, significantly enhancing the capture efficiency of unmodified magnetic nanoparticles. Additionally, the surface-modified coprecipitation particles showed robust interactions with polyethylene (PE) microparticles, leading to improved capture kinetics and efficiency in targeting MPs [33]. An above 99% removal percentage of 1 µm polystyrene microplastic was confirmed by using the functionalized commercial iron oxide (II–III) nanoparticles (50–150 nm) with phosphorus tungstic acid and different amines [34].

2.5. Photocatalytic and Electrochemical Materials

When exposed to light energy, photocatalytic degradation, a promising low-temperature treatment technique, uses catalyst-induced oxidation. Strong oxidizing active free radicals are produced during this process, and when they react with contaminants, the pollutants are removed. Photocatalysts are materials that decompose adverse/toxic substances when exposed to UV radiation from the sun [35]. Photocatalysts are used to treat water and air, manufacture and generate hydrocarbons, and transform certain compounds, as well as for medication delivery, photocatalytic water splitting, and self-cleaning coatings. Semiconducting metal oxides, including SnO₂, TiO₂, ZnO, Fe₂O₃, CeO₂, WO₃, ZrO₂, and V₂O₅, etc., were widely used as photocatalysts for several decades. Among these, the most popular are TiO₂ and ZnO, both of which have a suitable band gap that, upon interaction with light, generates a suite of reactive species (Figure 4). Their applications as photocatalysts have been made possible by their biocompatibility, remarkable stability, charge transport behavior, advantageous electronic structure combinations, excited lifetimes of metal oxides, and their capacity to produce charge carriers when stimulated with the required amount of light energy [36,37,38,39].

The oxide semiconductor titanium dioxide (TiO₂) is well known for its exceptional photostability and oxidation capabilities, which decompose various organic chemicals and polymers such as polyethylene, polystyrene, PVC etc. But below 385 nm, TiO₂′s catalytic activity is limited to the ultraviolet (UV) wavelength region; thus, it needs to be modified to operate better when exposed to sunlight. Multi-walled carbon nanotubes (MWCNTs) have been successfully used by researchers to enhance the photocatalytic activity of TiO₂ [40]. MWCNTs’ uniform structure promotes the best possible catalyst dispersion, and their large electron storage capacity quickly excites electrons when exposed to light energy, resulting in electron-hole pair recombination. This increases the efficiency of the catalyst by producing more active free radicals.

An et al. efficiently improved the composite photocatalyst of TiO₂ by preparing water-soluble MWCNTs via the acid stream method. Using the sol-gel solvothermal process, these MWCNTs were employed with nanosized TiO₂ particles to create a nanocomposite photocatalyst for polyethylene (PE) degradation [41]. The results showed that the degradation efficiency of TiO₂ could be tuned by changing the addition of MWCNT. This novel approach resulted in increased light absorption capacity by producing a composite photocatalyst with an absorption band that covers the whole UV-VIS spectrum. After 180 h of UV irradiation, the weight of the TiO₂-MWCNTs (20 wt%)-PE sample decreased by 35%. The degradation of polypropylene (PP) is a serious issue since it is the most hydrophobic polymer. Saifuddin et al. prepared the TiO₂ nanoparticles supported on amorphous carbon with nanoporosity (TiO₂@NC) and used as a photocatalyst to degrade macro-sized PP under the influence of a UV-C light source. In addition to that, the concept of an optimal removal rate was also introduced. It was found that 1 mg of ZnO nanorods could degrade 0.758 mg of PP microplastics. Under sufficient UV irradiation, they were able to degrade 0.843 mg of PP per 1 mg of TiO₂@NC-MOF using a TiO₂@NC-MOF catalyst. Notably, electrons and holes are produced when TiO₂ surfaces are exposed to UV light. However, active free radical production is enhanced by the tendency of these unaltered surface electrons and holes to recombine. To overcome this, TiO₂ needs support on a carrier that promotes quick electron transport. The electron-filling capabilities of transition metal borides have been advantageous [42].

The photocatalytic degradation of polyethylene (PE) MPs and PS microspheres was studied using TiO₂ nano-films under UV irradiation. The TiO₂ films achieved near-complete degradation (98.4%) of PS microspheres within 12 h, while PE MPs exhibited significant photodegradation after 36 h. Identified intermediate products included hydroxyl, carbonyl, and carbon-hydrogen groups, with CO₂ as the primary end product. Similarly, Tian [43] investigated the degradation of 14C-labeled PS nanoplastics under UV light in air and water. X-ray photoelectron spectroscopy (XPS) revealed the formation of C–O groups on the plastic surface after 48 h. Various low-molecular-weight compounds were identified, including condensed aromatic structures with –OH and C=O functional groups on their side chains, as well as oxidized monomers containing single benzene rings. The authors suggested that the hydrophilic products continue to degrade further. UV irradiation in air also led to a marked increase in the molecular weight of PS molecules, likely due to chain cross-linking. Photocatalytic decomposition of PE MPs and PS microspheres was evaluated using TiO₂ nano-films under UV irradiation [44]. TiO₂ films achieved approximately 98.4% degradation of polystyrene (PS) microspheres within 12 h. Polyethylene (PE) microplastics also showed significant photodegradation after 36 h of exposure. The intermediate compounds formed during the process included hydroxyl, carbonyl, and C–H functional groups, with CO₂ identified as the primary end product. Tian [43] studied the degradation of radiolabeled ¹⁴C-PS nanoplastics under UV light, with experiments conducted in both air and water environments. X-ray photoelectron spectroscopy analysis showed the presence of C–O functional groups on the plastic surfaces after 48 h of UV exposure. Several low-molecular-weight byproducts were also observed, consisting of condensed aromatic rings with side chains bearing –OH and C = O groups, as well as oxidized monomers containing single benzene rings. The study suggested that these hydrophilic products may undergo further breakdown. Additionally, UV irradiation in air led to an increase in the molecular weight of PS, which may result from chain cross-linking [43].

In another study by Lee et al., different TiO₂ and UV irradiation combinations were used to degrade the Polyamide 66 microfibers [45]. The degradation rate of microfibers was found to depend on the wavelength of UV light. UV-C irradiation resulted in significantly greater degradation than UV-A, with a 97% reduction in mass observed after 48 h, compared to only 6% under UV-A exposure. The concentration of TiO₂ also played a key role in the degradation process; the half-life of the microfibers decreased from 267 h at 20,000 mg/L TiO₂ to just 10 h at 100 mg/L TiO₂. These findings were also confirmed by another study conducted by Saquib et al., which showed that a concentration of TiO₂ beyond a particular range can effectively decelerate the degradation [46].

Figure 4. Mode of action of a photocatalyst for decomposition of PE chain: (a) single catalyst such as ZnO; [47] and (b) Fe-ZnO photocatalyst [48].

Figure 4. Mode of action of a photocatalyst for decomposition of PE chain: (a) single catalyst such as ZnO; [47] and (b) Fe-ZnO photocatalyst [48].

2.6. Filtration Materials

Filtration is one of the effective technologies for environmental pollution control, with easily adjustable pore sizes, that does not produce secondary contamination. Various materials and methods have been utilized to prepare filtration membranes and meshes used for wastewater treatment, most of which are based on polymer materials [49,50]. Filtration materials, including membranes, meshes, and adsorbents, are crucial in removing contaminants from water, air, and other media, addressing pollution from micro- and nanoparticles. The effectiveness of these materials relies on various properties, including pore size, surface area, and chemical characteristics, which determine their suitability for different applications. In recent years, nanotechnology and material science advancements have expanded these materials’ scope and efficiency, particularly in applications requiring high precision and selectivity [51].

Nanofiber membranes have emerged as an effective class of filtration materials due to their large surface area relative to volume, adjustable pore size, and robust mechanical properties. In recent years, membrane-based separation techniques have gained considerable interest for the task of eliminating microplastics and nanoplastics from wastewater [50]. Because the pore size of these membranes is often comparable to that of micro- and nanoplastic particles, they enable removal through mechanisms such as adsorption, electrostatic interactions, and physical entrapment [52]. Electrospun nanofibers, commonly used in these membranes, are highly sensitive to production conditions, including polymer type, voltage applied, flow rate of the solution, and the distance between the needle tip and collector. Even slight changes in these parameters can significantly impact the characteristics of the resulting nanofibers and, consequently, the overall filtration efficiency of the membrane. Produced mainly through electrospinning, nanofibers are often made from polymers such as polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and polysulfone, which are often used due to their hydrophilic nature and good mechanical properties. Regarding MP/NP removal, different methods have been applied in the production of PAN-based electrospun nanofibers to improve its properties for treatment [53,54]. Additionally, nanofibers can be surface modified with functional groups that improve hydrophilicity and enhance their ability to trap dissolved ions and organic compounds. Recent studies suggest that hybrid nanofiber membranes, which integrate adsorbent materials or catalytic nanoparticles, can further improve contaminant removal efficiency, even under low-pressure conditions. In the last treatment stage of a sewage treatment plant, Ziajahromi et al. examined the removal of microplastics (100–190 μm) using an advanced treatment unit called an ultrafiltration-reverse osmosis combined system [55]. The results showed that during ultrafiltration and reverse osmosis filtration, the concentration of microplastics dropped from 2.2 particles/L to 0.28 and 0.21 particles/L, respectively, and that the overall removal rate of microplastics was greater than 90%.

Polymer membranes, such as those made from polyethersulfone (PES), polyethylene (PE), and polypropylene (PP), are well-established in the filtration industry due to their durability, cost-effectiveness, and ease of fabrication. These membranes typically function through microfiltration or ultrafiltration, where pore sizes can be adjusted to target specific pollutants ranging from suspended solids to larger pathogens. Unlike nanofibers, polymer membranes often prioritize permeability over extremely fine filtration, making them suitable for large-scale operations where the balance between flow rate and selectivity is critical [56,57].

2.7. Electrocoagulation

Electrocoagulation (EC) is a technique that utilizes electric current to destabilize and aggregate particles, facilitating the removal of MPs and NPs. During EC, metal electrodes (typically aluminum or iron) undergo oxidation, releasing metal cations into the water and forming coagulants like metal hydroxides. These coagulants adsorb and aggregate plastic particles into larger flocs, making their separation easier by sedimentation or filtration. The advantage of EC is its simple operation, cost-effectiveness, and ability to treat various contaminants, including plastics of varying sizes. Studies have demonstrated that EC can effectively reduce microplastic concentrations; however, its efficiency can depend on the plastic type, solution pH, and current density [58]. Recently, this technique has gained attention due to its environmentally friendly nature and minimal chemical use. Since the technique can achieve a high removal efficiency of more than 90%, electrocoagulation has been utilized extensively to remove MP/NP from urban waterways. According to Akarsu and colleagues, the Fe–Al electrode can be used in an electrocoagulation-electroflotation technique to remove 98% of the MPs (15,804 particles L⁻¹) in laundry wastewater. Since Al anodes perform better at removal than Fe anodes, they are utilized in the majority of research. In particular, aluminum electrodes are capable of rapidly producing flocs such as Al(OH)₃ and AlOOH, which possess strong adsorption abilities for microplastics and nanoplastics. In contrast, flocs formed by iron anodes tend to be denser and settle quickly, which can reduce their interaction time with MPs/NPs. Electrocoagulation has become a widely adopted method for removing MPs and NPs from urban water systems, often achieving removal efficiencies exceeding 90%. For example, Akarsu and colleagues demonstrated that approximately 98% of microplastics (1.5 × 10⁴ particles per liter) in laundry wastewater were effectively eliminated using a combined electrocoagulation-electroflotation process with Fe–Al electrodes. [59]. In most of the research, Al-based anodes are used for their better removal performance than Fe anodes [60]. The main reason appears to be that flocs generated by the Fe anode form a dense feature and rapid sedimentation, which limits their interaction with MPs/NPs; however, on the other hand, the Al electrode can produce flocs with a high speed and robust adsorption efficiency towards MPs/NPs [43]. Diverse MPs may be removed from artificial wastewater using an Al anode with 93.2% removal efficiency for granular PE (average size of 286.7 μm), 91.7% removal efficiency for granular PMMA (average size of 6.3 μm), 98.2% removal efficiency for fibrous CA (1–2 mm), and 98.4% removal efficiency for fibrous PP (1–2 mm) [61]. A magnetic stirrer can be used inside the electrochemical reactor to uniformly disperse the flocs that are produced. Therefore, these actions can accelerate the coagulation/flocculation process and improve the mass transfer of flocs, as shown in Figure 5 [62].

In summary, both electrocoagulation and degradation-based approaches offer potential solutions for mitigating the impact of MPs and NPs in the environment. However, optimizing these processes and ensuring their scalability and safety remain crucial challenges for real-world applications.

2.8. Applications in Different Environmental Matrices

A summary of studies on the different materials used for the removal of MPs/NPs from different matrices, including natural water, marine water, drinking water, soil and sediment, is presented in

Table 1. Microplastic removal from different environmental matrices.

Removal Process	Removal Techniques	Materials	Types of MP/NPs	MP/NPs Size	% MP/NPs Removed	Reference
Natural water
Adsorption, Photocatalytic and Electrochemical Materials	Biochar and Modified Magnetic Biochar (MBC)	MBCs	PS	1 µm	94.81	[11]
		Mg-MBCs	PS	1 µm	98.75
		Zn-MBCs)	PS	1 µm	99.46
	Sponge	Chitin and graphene oxide (ChGO) based sponge	PS	1 µm	92.2	[13]
	3 dimensional graphene	Three-dimensional reduced graphene oxide (3D RGO)	Monodisperse PS	5 µm	56.08	[23]
	Oat protein sponges	Oat protein isolates	PS	1 µm	81.2	[11]
	Zirconium-based MOF foam with Zn-Al LDH	Zn-Al LDH	PS	55 nm	100	[63]
	Zirconium metal organic frame work based foam	UiO-66-OH@MF-3	PVDF	~260 nm	95.5 ± 1.2	[64]
			PMMA	~325 nm
			PS	~183 nm
	Granular activated carbon (GAC)	Granular coconut shell based Activated Carbon	PS latex NPs	90 ± 7 nm	90	[25]
	Coffee grounds	Coffee grounds biomass	PS (fluo-NP)	100 nm	74	[65]
	Hydrophobic Fe nanoparticles	Modified Fe nanoparticles	MPs	1–8 nm	74–105	[31]
				200 µm–1 nm	59–100
				<20 µm	~90
	Magnetic carbon nanotubes	M-CNTs	PE, PET, and PA	48 µm	100	[66]
Filtration	Electrocoagulation	Reactor, electrodes	PE	300–355 µm	90–100	[67]
	Biofilter structures	Crushed light-expanded clay aggregates with and without biochar	PE	100 µm	100	[68]
	Pressure-sensitive adhesive	Zirconium silicate beads coated with poly (2- ethylhexyl acrylate)	PS	10 µm	99	[69]
	Silica-based ceramic hollow fiber microporous membrane	Guinea cornhusk ash (GCHA)	PVC, PVP, PAN, PMMA	-	88–97.2	[70]
	Natural Bioflocculant	Lysozyme amyloid fibrils	PS	500 nm	93.4–98	[71]
	Solar energy	Spherical K5 glass balls	PS	60 nm	74	[72]
	Marine water
	Non-fluorinated	Combining anodization and liquid phase of lauric acid	PP	262 ± 4 µm	>99	[73]
	MP concentrator (MPC)	Patterned PDMS bonded with oxygen plasma	PS	1–20 µm	≥90	[74]
	Microbes	Extracellular polymeric substances (EPS)	PMMA, PS	106–250 µm	N/A	[75]
	Bacterial biofilm	EPS	MPs	106–300 µm	N/A	[76]
	PDA@Fe3O4 (MagRobots)	Coating Fe3O4 nanoparticles	MPs solution	-	N/A	[77]
Drinking water
Filtration	Alum-based coagulation-flocculation-sedimentation (CFS)	CFS	PS	3, 6, 25, 45 45 and 90 µm	~100	[78]
	Alum coagulation	CFS	PE, Rayon, Polyester	1–5 µm	N/A	[79]
	Coagulation	Coagulant: AlCl3.6H2O	PE	<0.5–5 mm	36.89 ± 1.06	[80]
	Coagulation	Ferric and aluminium Sulphate coagulats	Pristine PVC	<50 µm	~80	[81]
	Coagulation	Fe-based coagulants	PE	0.5–5 nm	87.66–90.91	[82]
	Sand filtration	Coagulation	PS	10, 20, 45 and 90 µm	77.4–95.3	[83]
	Magnetic Separation	Magnetic polyoxometalate ionic-liquids	PS	N/A	90	[84]
Soil
Filtration	Density Separation	NaCl, ZnCl2, DI water, NaI	PE, PP, PET, PAN	0.02–0.25 mm	N/A	[85]
	Filtration	Filter papers	PET, PP.LDPE, PVC, HDPE, PS	0.25–1 mm	51–99	[86]
	Oil-based extraction	Coaster and olive oil	PS, PE, PVC, PET, polyurethane and poly-carbonate	5 μm to 300 μm	90–97%	[87]
	Flotation method	DI water	PE, PP	>100 μm	90	[88]
Sediments
Filtration and/or sieving	Oxidizing digestion	H2O2	PS, fibers	size > 1 mm	65.8–98	[88]
	Alkaline digestion	A mixture of urea: thiourea: NaOH	PET, nylon	>45 μm	100	[89]
	Density separation	NaCl, NaBr, NaI, ZnBr2	PS, Nylon, PVP, HDPE, PET, Mixed MPs	<1 mm	91–99	[90]
	Heat assisted density separation	Sodium dihydrogen phosphate solution	PS, PE, PVC, PP, PET, Polyamide	0.1 to 1 mm	93	[67]
	Digestion method	H2O2	PP, PS, PE, PET and PA	>1 mm	100	[91]
	JAMSTEC MPs- Sediment separator	Small device	PE, PP, PVC, PET, PS	<1000 µm	92–98	[92]
	Sieving Method	Sodium polytungstate (SPT)	62 MPs	5 mm–250 μm	97	[67]

.

Based on the data compiled in Table 1, it is clear that the removal efficiency of micro- and nanoplastics (MPs/NPs) depends heavily on the material used, the type of plastic, and the particle size. For instance, Zn- and Mg-modified magnetic biochars have demonstrated very high removal rates—over 98% for 1 µm polystyrene particles—while zirconium-based MOF foams also achieved near-complete removal of nanoplastics [11,12]. In contrast, more conventional methods like sand filtration, alum-based coagulation, or unmodified filter papers tended to perform less effectively, especially for smaller particles. These differences are likely influenced by factors such as surface charge, porosity, and interaction mechanisms like electrostatic attraction or hydrophobicity. While a few studies have investigated the impact of initial MP/NP concentrations on removal performance, these findings are not yet standardized. This lack of uniformity across testing conditions makes direct comparison difficult and highlights the need for consistent, concentration-based evaluation methods in future research.

3. Emerging Technologies and Novel Materials

3.1. Novel Laser-Based Technology

Laser light consists of photons that are of a single wavelength (color) and phase, which makes it highly focused, intense, and directionally stable. This coherent energy can be directed onto a small area, allowing detailed excitation of specific molecules or atoms within a sample [93]. In spectroscopic applications, laser techniques take advantage of this energy to either induce a response (like fluorescence or Raman scattering) or to ablate the sample’s surface, releasing particles for analysis, as in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The resulting interactions reveal information about the sample’s molecular, elemental, or structural composition [94]. The use of laser-based technology for removing microplastics from various environmental matrices is an emerging concept that could revolutionize environmental cleanup efforts. Laser technologies can play a vital role in addressing MPs in water, air, soils, and other environmental matrices. The commonly employed laser techniques are focused on the identification and characterization of MPs in various matrices; these techniques also combine laser technology with several analytical techniques [95,96]. These laser techniques include laser-induced breakdown spectroscopy (LIBS), laser-induced fluorescence, Raman spectroscopy, Quantum cascade laser imaging (LDIR), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) [97,98,99,100,101]. LIBS is a fast, in-situ technique that can identify microplastics by their spectral fingerprints. This technique can also detect heavy metals adsorbed to the surface of microplastics [102]. Laser-induced fluorescence technique analyzes the fluorescence spectra emitted by microplastic samples when irradiated with a laser [99]. To differentiate between various types of microplastics, dimension reduction techniques like principal component analysis (PCA) have been applied to fluorescence data, helping to reveal unique spectral features and facilitate the classification of microplastic types [103]. The Raman spectroscopy technique, on the other hand, has been used to detect and classify aged microplastics by analyzing the molecular vibrations of the sample, revealed through its unique Raman scattering patterns when exposed to laser light. This allows for the detailed identification of polymer types and the assessment of degradation states [100]. The use of quantum cascade laser imaging or the Laser Direct Infrared (LDIR) technique in MP analyses is also common. In this technique, a tunable quantum cascade laser (QCL) is employed to target and focus precisely on MP particles [101,104]. The advantages of this include faster imaging and the generation of stronger signals compared to traditional imaging systems, making this technique highly effective for detailed particle analysis. LA-ICP-MS is a technique that detects and quantifies trace metals in microplastics and biofilms. By ablating the sample with a laser and analyzing the ionized particles, LA-ICP-MS provides precise elemental composition data, making it valuable for environmental and material studies [97,105]. While laser-based techniques have been used in research that analyze and identify MPs, the use of laser-based techniques for the direct removal of MPs from the environment is currently in its nascent stages. In recent years, research reporting the use of lasers in combination with several physical removal techniques like filtration or magnetic separation have been developed. To this effect, methods have been reported that include laser enhanced photocatalysis [106], laser assisted membrane filtration [107], laser induced graphene filters [108] and laser ablation combined with magnetic separation [12,106,107,108,109,110]. Laser-enhanced photocatalysis for microplastic removal is an advanced technique that utilizes laser activation to enhance the photocatalytic degradation of microplastics. In this process, a photocatalyst (often a semiconductor material like TiO₂) is irradiated with laser light, which provides the energy to generate reactive species (e.g., hydroxyl radicals) on the photocatalyst’s surface. These reactive species then break down the chemical bonds in microplastics, leading to their degradation into smaller, less harmful compounds or even their complete mineralization. Sima et al. reported the effective degradation of polystyrene microplastics (PS-MPs) at low temperatures through Non-Thermal Plasma-Assisted Catalytic Oxidation. In their study, they developed a two-stage plasma system combining dielectric barrier discharge (DBD) plasma and a plasma-activated Hopcalite catalyst to degrade polystyrene microplastics (PS-MPs) at low temperatures, achieving a 98.4% conversion to CO₂ within 60 min. Plasma-generated reactive oxygen species (ROS) enabled PS-MP degradation, while the Hopcalite catalyst facilitated the complete oxidation of by-products. Additionally, cycling experiments demonstrated high stability, with a 93.2% conversion to CO_x and 99.5% CO₂ content after 10 cycles, suggesting this plasma-catalysis approach is highly effective for microplastic removal [106]. Membrane technologies, such as ultrafiltration (UF) and nanofiltration (NF), are proposed to efficiently remove microplastics. This technology employs lasers to clean or modify membrane surfaces, improving their filtration efficiency [109]. For example, lasers can remove fouling (clogging) that reduces membrane performance in capturing small particles like microplastics [52,109]. A recent study by Sun et al. developed a laser-modified graphene oxide (LGO) membrane with enhanced microstructure and super-hydrophilic properties, enabling high-efficiency microplastic (MP) filtration without using potentially harmful surface modifiers [107]. The LGO membrane’s unique “labyrinth” structure and optimized surface roughness achieve a remarkable filtration efficiency of ~99% for MPs, alongside a high water permeance (3396 L m² h⁻¹ bar⁻¹) [107]. Researchers are exploring the use of lasers to convert carbon-based materials into graphene, which is then used to create highly effective filters. These filters can trap microplastics in water, potentially working alongside other filtration or chemical treatments. A recent study by Jeong et al. reported an innovative approach to microplastic (MP) removal using laser-induced graphene (LIG) particles. The researchers developed magnetic Fe₃O₄-LIG particles by laser-treating a polymer mixture of iron oxide, lignin, and polydimethylsiloxane, creating an efficient, reusable adsorbent. The Fe₃O₄-LIG particles reportedly captured MPs (melamine, polystyrene, polyamide) with particle sizes ranging from 2 to 50 μm in under 300 min, with adsorption capacities reaching up to 1400 mg/g, and were easily separated from water using magnetic force [108]. This method offers a high-capacity, sustainable solution for MP remediation, showcasing the potential of laser-induced graphene in environmental cleanup efforts. Another technique employing laser technology for microplastic removal from the environmental matrix involves the combination of laser ablation with magnetic separation [33,110]. Laser ablation can be used to break microplastics into smaller, less harmful particles. This method can then be paired with magnetic nanoparticles, which can bind to microplastics, allowing for easier removal using a magnetic field [33]. Laser-based technologies offer a precise, efficient, and adaptable approach for identifying, targeting, and removing microplastics from various environments, contributing to improved environmental cleanup efforts.

3.2. AI-Driven Solution for the Removal of Nano and Microplastic

Another emerging technology for nano- and microplastic removal is the use of artificial intelligence (AI). In the context of microplastic removal, artificial intelligence (AI) refers to the application of machine learning algorithms, data processing techniques, and autonomous systems to enhance the detection, identification, sorting, and degradation of microplastics in various environments (Figure 6) [19,111,112]. AI can be employed to optimize filtration processes by analyzing sensor data that detects plastic particles, adjusts flow rates, membrane cleaning intervals, and pressure settings in real-time, also improving the efficiency of ultrafiltration and nanofiltration methods used in water treatment [113]. Optical detection methods combined with AI are increasingly used to enhance plastic identification and separation [114].

Another method involves the use of machine learning (ML) algorithms to emulate human intelligence by employing data from sensors or cameras to identify, classify, and sort plastics in real time [115]. Main ML methods often employed for waste management are the supervised learning and neural network models applications [116,117]. These algorithms are trained to detect micro- and nanoplastics using image recognition from microscopes or spectrometers [118]. When integrated with laser-induced breakdown spectroscopy (LIBS), AI rapidly identifies plastic composition and size, enabling more effective sorting and removal in wastewater treatment [119]. Autonomous robots with AI have been employed to locate and capture microplastics in various environments. These robots analyze environmental conditions, locate high concentrations of microplastics, and collect them, while continuously learning optimal strategies for varying conditions [120,121]. Furthermore, in some waste management systems, AI-guided sorting robots are beginning to supplement optical sorters, improving sorting efficiency by purging incorrectly sorted plastics (Figure 7) [121,122].

In some systems, deep learning is combined with visible (VIS) or near-infrared (NIR) detection to further enhance sorting accuracy [123,124]. Machine learning models can also predict microplastic distribution across ecosystems based on environmental factors like currents, wind patterns, and pollution sources, optimizing removal efforts in high-risk areas [125,126]. The performance of ML models, however, depends on computational resources, training time, and classification complexity [127]. The integration of cyber-physical systems, blockchain, ML, and IoT streamlines into waste management has enhanced the efficiency of identifying and sorting recyclable plastics [128,129]. AI can also be employed to design and optimize smart materials, like magnetic nanoparticles or adsorbents, for binding or degrading microplastics. This can be achieved by analyzing datasets on the interactions between these materials and microplastics. AI is then employed to customize materials for specific pollution scenarios [130]. Das et al. reported a technological development employing ML to refine magnetic nanoparticle characteristics (e.g., surface area, magnetic strength) to enhance the adsorption and degradation of plastics [130]. Finally, AI-driven analysis can also optimize conditions like pH and temperature to accelerate degradation, with real-time AI systems adjusting treatment parameters for maximum efficiency [131]. The integration of AI with emerging technologies, such as laser-based detection and advanced filtration, provides possible solutions that can enhance the sustainability and adaptability of microplastic removal, supporting resource-efficient practices in environmental protection.

Many advanced techniques for MP/NP removal demonstrate excellent performance at the laboratory scale; however, scalability and cost remain major barriers to industrial adoption. For example, magnetic nanomaterials and MOF-based systems show high removal efficiencies, but are often limited by complex synthesis procedures and high production costs [32,72]. In contrast, materials like biochar, activated carbon, and unmodified natural clays are significantly more affordable and easier to produce in bulk, making them more attractive for large-scale use, especially in developing regions [3,51]. Moreover, techniques that rely on existing infrastructure—such as granular filtration or coagulation—can be integrated into current water treatment systems with minimal modification, improving cost-effectiveness and feasibility. Thus, the commercial potential of a material depends not only on its removal efficiency but also on factors like material availability, regeneration capacity, and compatibility with existing treatment platforms.

3.3. Promising and Scalable Materials for MP/NP Removal

Selecting the most effective material for micro- and nanoplastic removal depends on several factors, including removal efficiency, reusability, environmental safety, cost, and ease of large-scale production. Materials that combine high adsorption capacity with stability and affordability are generally more attractive for practical use. Among the most promising candidates are activated carbon, biochar, magnetic nanoparticles, and certain polymeric membranes. Activated carbon and biochar, in particular, have been widely studied due to their low cost, porous structure, and strong affinity for hydrophobic microplastics [3]. Biochar’s versatility—especially when derived from agricultural waste—and its ability to be modified (e.g., with metals like Zn or Fe) further enhance its performance and scalability [132]. Magnetic nanoparticles (such as functionalized Fe₃O₄) have gained attention for their ease of recovery and strong removal efficiency, but challenges remain in terms of synthesis cost and potential environmental impact. Still, their integration with other materials or as a part of composite systems could pave the way for real-world applications [133].

In recent years, AI-assisted platforms and smart materials are emerging as a major trend. These technologies can optimize removal processes in real-time and are expected to be part of future decentralized or autonomous water treatment systems [19]. In addition, hybrid systems that combine adsorption, filtration, and catalytic degradation (e.g., biochar + membrane, or magnetic + photocatalytic materials) are gaining momentum due to their ability to tackle a broader range of particle sizes and environmental conditions [134]. Looking ahead, the development of low-cost, multifunctional, and environmentally safe materials that work across diverse matrices (water, soil, air) will likely be the focus. To support commercialization, materials that are regenerable, easy to deploy, and compatible with existing treatment infrastructure will be key.

An overview of the advantages and disadvantages of various conventional and emerging removal techniques are presented in

Table 2. Advantages and disadvantages of various conventional and emerging removal techniques.

Removal Method	Advantages	Disadvantages	Refs.
Filtration (Membrane, Nanofiber, Ultrafiltration)	High efficiency in removing MPs/NPs, well-established technology	Prone to fouling, high maintenance costs	[49,50,55]
Adsorption (Activated Carbon, Biochar, Graphene-based materials)	Cost-effective, high adsorption capacity	Requires regeneration, limited selectivity for different MPs/NPs	[7,8,11]
Coagulation & Flocculation	Simple and scalable for wastewater treatment	Ineffective for small-sized NPs, generates sludge	[58,59,60]
Electrocoagulation	High removal efficiency, minimal chemical use	Energy-intensive, requires electrode maintenance	[15,61,62]
Photocatalysis (TiO2, ZnO, Fe-based catalysts)	Can degrade MPs into harmless byproducts	Requires light source, slow reaction time	[35,36,44]
Magnetic Nanoparticles	Rapid and selective removal, reusable	High synthesis cost, requires optimization	[31,32,33]
AI-driven Optimization	Enhances process efficiency and automation	Requires advanced infrastructure, high initial cost	[19,111,112]
Laser-based Removal	Potentially efficient for microplastic degradation	Still in research phase, high energy demand	[13,106,108]

.

4. Conclusions

Microplastics (MPs) and nanoplastics (NPs) continue to pose serious environmental and health risks due to their persistence, mobility, and accumulation across various ecosystems. In this review, we have provided a broad overview of materials and strategies used for their removal, including conventional methods like filtration and coagulation, as well as advanced approaches such as adsorption, photocatalysis, magnetic separation, and emerging technologies like laser-assisted systems and AI-driven solutions. What sets this review apart is its attempt to integrate insights across water, soil, and air systems, rather than focusing only on aquatic environments. We have also pointed out specific research gaps, such as the lack of standardized detection methods for NPs, underexplored remediation techniques for air and soil matrices, and the limited scalability of many lab-scale technologies. A brief section was added to explain the major mechanisms behind MP/NP removal, such as adsorption, electrostatic interactions, physical filtration, photocatalytic degradation, and electrocoagulation. While high-performance materials like Zn/Mg-modified magnetic biochar and MOF-based sponges have shown removal efficiencies exceeding 90% in lab settings, their real-world application is still constrained by synthesis cost, fouling issues, and maintenance challenges. On the other hand, cost-effective materials, such as activated carbon, unmodified biochar, and granular filtration media, were highlighted for their potential scalability and commercial viability.

We also incorporated new methods such as electrochemical oxidation and flow cytometry, which have shown promising results in recent studies for removing small-sized MPs and NPs. Real-world implementation faces several hurdles, including the lack of international regulations on allowable MP/NP concentrations in drinking water and the high cost of adopting advanced treatment technologies.

Based on the literature reviewed, we recommend the following practical strategies:

• Combining multiple removal mechanisms (e.g., adsorption + magnetic capture) for better efficacy.
• Developing decentralized or small-scale systems for areas without centralized wastewater treatment.
• Conducting pilot-scale studies and life-cycle assessments to evaluate feasibility and environmental impact.
• Supporting international efforts to establish standardized detection methods and regulatory guidelines

Overall, this review not only summarizes current technologies but also aims to guide future research by highlighting the gaps and opportunities in this evolving field. A collaborative approach that includes scientists, engineers, policymakers, and industries will be key to addressing the growing challenge of micro- and nanoplastic pollution.