Search Results (196)

Titanium compounds are an integral component for paint pigments, food additives (E171), catalysts, precursors for resistant structural materials, medicine, and water, and air purification and disinfection processes. A new and rather promising trend for titanium dioxide production is obtaining it from minerals with magnesium titanium structure. Magnesium titanates obtained by pyrometallurgical processing of quartz–leucoxene concentrate (oil sandstones). It was found that the optimal pyrometallurgical processing conditions were 4 h and a temperature of 1425–1450 °C, with TiO₂ → Mg_XTi_YO_Z conversion exceeding 95%, and that sulfation of the magnesium titanate mixture with 60–70% H₂SO₄ for 150–210 min allows a 95% extraction of titanium compounds into solution. Investigation of the mechanism of titanium compound precipitation from Mg-Ti-containing sulfuric acid solutions revealed that in the pH range from 3 to 6, only titanium compounds were extracted from solution, while coprecipitation of magnesium compounds begins only at pH above 6.5. The product obtained by precipitation is titanium dioxide with an anatase structure, with particle distribution ranging from 0.8 to 5.0 µm and a developed surface area over 250 m²/g with mesopores characteristic of sorption materials. Full article

The increasing demand for clean and sustainable energy has driven significant research into hydrogen production from biomass-derived feedstocks. Unlike the gasification route, the pyrolysis of biomass followed by steam reforming of bio-oil (SRBO) offers several advantages, including the liquid nature of bio-oil and the operation at lower temperatures, which facilitate easier transportation and storage compared to raw biomass. The conventional SRBO process faces several limitations, mainly catalyst deactivation due to significant coke formation and metallic sintering, as well as low hydrogen yield and purity. Hence, the intensified sorption-enhanced steam reforming of bio-oil (SESRBO) is a promising strategy to overcome these drawbacks, to simultaneously produce high-purity hydrogen and capture carbon dioxide in situ from the reaction media. This critical review presents an in-depth comparative analysis of conventional and intensified steam reforming of bio-oil, with a focus on associated challenges. Special attention is given to recent developments in the design of bifunctional materials (BFMs), which integrate both catalyst and sorbent into a single particle, along with process optimization focusing on key parameters, i.e., reforming temperature and steam presence. Finally, the review highlights key research gaps and future directions to overcome existing challenges in achieving cost-effective and scalable hydrogen production. Full article

Polyurethane (PU) is widely recognized for its efficient oil sorption properties. However, this capacity is highly dependent on its intrinsic chemical composition and morphological structure, which can be altered by mechanical or chemical treatments commonly applied before using it as a sorbent. In this study, we present a comprehensive investigation of the oil sorption behavior of both soft and rigid PU foams, and their blade-milled ground (BMG) counterparts obtained by mechanical treatment of several recycled PU-based products, including seats, mattresses, side panels of cars, packaging components, and insulating panels of refrigerators and freezers. We found that blade milling the soft PU foams leads to a significant reduction in oil sorption capacity proportional to the extent of grinding. Pristine soft PU foams and BMG-PUs with intermediate particle size (−250 μm–1 mm) exhibited the highest oil uptake (20–30 g/g), whereas the finest fraction (5 μm–250 μm) showed a lower capacity (3–7 g/g). In contrast, rigid PU foams showed consistently low oil sorption (~5 g/g), with negligible differences between the original and ground materials. At the macroscopic level, optical and morphological analyses revealed the collapse of the 3D porous network and a reduction in surface area. On the microscopic scale, spectroscopic, structural, and thermal analyses confirmed phase separation and rearrangement of hard and soft segmented domains within the polymer matrix, suggesting a different mechanism for oil sorption in BMG-PU. Despite reduced performance compared to pristine foams, BMG-PU powders, especially those with intermediate dimensions and originating from soft PU foams, present a viable, low-cost, and sustainable alternative for oil sorption applications, including oil spill remediation, while offering an effective strategy for effective recycling of PU foam wastes. Full article

Simulation studies of adsorption in complex effluents are challenging due to nonlinear interactions between sorbents, adsorbates and carrying flows. This study investigates effluents from oil and textile industries, characterised by their heavy metal content and chemical oxygen demand. It examines the process in a continuous-flow laboratory-scale adsorption system. Results were validated using process modelling based on mass and energy conservation, applied to an industrial adsorber. The model described surface sorption mechanisms on bioactivated carbon at the molecular level and predicted breakthrough curve profiles, integrated with Aspen Plus ^® adsorption simulation under industrially relevant conditions. Experimental data and model predictions showed good agreement, with relative deviations ranging from 0.2% to 24.6%. Differences in adsorption capacities between oily and textile effluents highlighted the influence of coexisting constituents. At the same time, the varied behaviour of identical components supported the hypothesis of multifactorial effects in complex mixtures. The optimisation study, using Response Surface Methodology with a Central Composite design, evaluated factors such as bed height, feed rate, and adsorption cycle time, achieving enhanced removal efficiencies of 62% for chemical oxygen demand and 25% for suspended solids. Full article

Bentonite is the most widely used raw material for producing organoclays, which have numerous industrial and environmental applications. Due to their hydrophobicity, high swelling, and strong affinity for organic compounds, organoclays are effective in removing organic solvents from contaminated water originating from pipeline leaks, oil spills, traffic accidents, and industrial discharges. Such contamination not only degrades water quality but also forms surface films that hinder oxygen transfer, threatening aquatic ecosystems. In this study, two sodium bentonites with different specific surface areas (30 and 50 m²/g) were modified with three quaternary ammonium salts of varying molar masses and alkyl chain lengths (Sun, Arq, and Arm) to evaluate their performance in organic solvent sorption (gasoline, diesel, and kerosene). The materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM), and swelling capacity and sorption efficiency. The swelling capacity was determined according to ASTM D5890-19 (Foster method) using gasoline, diesel, kerosene, toluene, and xylene, while the sorption efficiency was assessed following ASTM F726-17 in gasoline, diesel, and kerosene, chosen due to their high potential for water contamination and frequent occurrence in oil spill and leakage scenarios. These solvents also differ in polarity and aromatic content, providing a relevant model for hydrocarbon mixtures commonly found in the environment. Results showed that the interaction between the clay and the surfactant depended strongly on the modifier’s chemical structure. The sorption capacity increased with greater interlayer expansion, surfactant molar mass, and specific surface area of the clay. Among all samples, the Arm-modified natural bentonite (VLArm) exhibited the best performance, with adsorption capacities of up to 6 g/g for diesel, 5 g/g for gasoline, and 5 g/g for kerosene. These values exceeded most previously reported organoclays. These findings demonstrate that optimizing the combination of clay properties and surfactant chemistry can yield highly efficient, low-cost organoclays for environmental remediation of organic contaminants. Full article

Frequent crude oil spills during offshore oil and gas production and transportation have inflicted irreversible detrimental effects on both human activities and marine ecosystems; with particular risks of secondary disasters such as combustion and explosions. To address these challenges; advanced oil sorption technologies have been developed to overcome the inherent limitations of conventional remediation methods. In this study, a flame-retardant protective coating was fabricated on melamine sponge (MS) through precipitation polymerization of octa-aminopropyl polyhedral oligomeric silsesquioxane (POSS) and hexachlorocyclotriphosphazene (HCCP), endowing the MS@PPOS-PDMS-Si composite with exceptional char-forming capability. Secondary functional layer: By coupling the complementary physicochemical properties of polydimethylsiloxane (PDMS) and SiO₂ nanofibers, we enabled them to function jointly, achieving superior performance in the material systems; this conferred enhanced hydrophobicity and structural stability to the MS matrix. Characterization results demonstrated a progressive reduction in peak heat release rate (PHRR) from 137.66 kW/m² to118.35 kW/m², 91.92 kW/m², and ultimately 46.23 kW/m², accompanied by a decrease in total smoke production (TSP) from 1.62 m² to 0.76 m², indicating significant smoke suppression. Furthermore, the water contact angle (WCA) exhibited substantial improvement from 0° (superhydrophilic) to 140.7° (highly hydrophobic). Cyclic sorption–desorption testing revealed maintained oil–water separation efficiency exceeding 95% after 10 operational cycles. These findings position the MS@PPOS-PDMS-Si composite as a promising candidate for emergency oil spill response and marine pollution remediation applications, demonstrating superior performance in fire safety, environmental durability, and operational reusability. Full article

This study examines the swelling behaviour of nitrile-butadiene rubber (NBR) when interacting with tyre pyrolysis oils (TPO), with a focus on the chemical composition of TPO and their interaction with rubber matrices. Initially, a comparative analysis with conventional diesel fuel (DF) was performed using advanced analytical techniques, including two-dimensional gas chromatography coupled to mass spectrometry (2D-GC/MS), infrared (IR) spectroscopy, and nuclear magnetic resonance (¹H-NMR) spectroscopy. The analysis revealed that TPO contains a significantly higher proportion of aromatic hydrocarbons than DF, along with unsaturated and oxygen-containing compounds not present in DF. Based on these compositional differences, blends of TPO and DF were formulated and evaluated for their suitability as liquid energy carriers according to the specifications of DF. In principle, blends with an addition of up to 5 vol% TPO in DF are technically suitable for use as fuel. Subsequently, the sorption behaviour of TPO, DF, and their blends in NBR was investigated. The swelling potential was determined based on mass, density, and volume, and the changes in the hardness and tensile strength of NBR were recorded. The results demonstrate that TPO induces pronounced swelling in NBR, as evidenced by a marked increase in mass uptake and volume expansion. A linear increase was observed between the degree of swelling and the increasing TPO content in the blends. Mechanical property assessments revealed a corresponding decrease in the hardness and tensile strength of NBR upon exposure to TPO, with the most severe effects associated with neat TPO. This work provides a comprehensive assessment of TPO as a potential blend component for DF. It highlights the need for careful consideration of material compatibility in practical applications. Full article

One of the current and serious environmental problems is the pollution due to microplastics. There is an urgent need for biodegradable and bio-based materials for numerous applications, including food packaging. In this work we examine the bio-based polyester cutin for its potential to be used as food packaging material, in terms of migration, based on the Hansen Solubility Parameters (HSP). Cutin is a cross-linked polymer that is swelled by various solvents. We use the degree of swelling of cutin in carefully selected solvents of various polarities in order to estimate the HSP of cutin. Some solvents can induce alteration of the chemical structure of cutin, as proven by Fourier Transform Infrared (FTIR) measurements. This interferes with the process of estimation of the HSP and is discussed in depth. The distance R_a and the Relative Energy Difference (RED) between the HSP of cutin and various food components are calculated and used to predict the existence of favorable interactions between cutin and the food components, which is translated to a high probability for the existence of migration and permeation. Experimental confirmation of one prediction based on HSP is provided by UV-VIS photometry. Similar calculations were performed for other polyesters (poly(lactic acid) and poly(hydroxy butyrate)). Cutin exhibits compatibility with substances of low polarity, such as fats and lipids and non-polar compounds found in essential oils. Thus, migration into fatty foods is expected as well as sorption and permeation of some (volatile) compounds into cutin. Nevertheless, we conclude that the overall migration risk for cutin is lower than the one of other bio-based polyesters. HSP can be used for initial screening of potential migration risks; however, further research is necessary in order to assess the occurrence, extent, and significance of the actual migration. Full article

Among the main man-made water pollutants that pose a danger to the environment are oil products, heavy metals, and radionuclides, as well as micro- and nanoplastics. To purify such waters, it is necessary to use advanced methods, with sorption being one of them. The aim of this work is to develop a nano-functionalized composite, comprising magnetically responsive, thermally expanded graphite (TEG) and the natural clay bentonite, and to assess its ability to purify man-made contaminated waters. Throughout the course of the research, the methods of scanning electron microscopy, optical microscopy, dynamic light scattering, radiometry, and atomic absorption spectrophotometry were used. The use of the TEG–bentonite composite for the purification of the model water, simulating radioactively contaminated nuclear power plant (NPP) effluent, reduced the content of organic substances by 10–15 times, and the degree of extraction of cesium, strontium, cobalt, and manganese was between 81.4% and 98.8%. The use of the TEG–bentonite composite for the purification of real radioactively contaminated water obtained from the object “Shelter” (“Ukryttya” in Ukrainian), in the Chernobyl Exclusion Zone, Ukraine, with high activity, containing organic substances, including micro- and nanoplastics, reduced the radioactivity by three orders of magnitude. The use of cesium-selective sorbents for additional purification of the filtrate allowed for further decontamination of radioactively contaminated water with an efficiency of 99.99%. Full article

Polymer-based aerogels have recently received considerable research attention as a favorable option for oil–water separation due to their enhanced porous 3D structure with great specific surface area, low density and outstanding sorption behavior. Additionally, polymer-containing aerogels exhibit more favorable characteristic properties, such as being lipophilic–hydrophobic (superhydrophobic–superoleophilic), hydrophilic–lipophobic (superhydrophilic–underwater oleophobic), or other specific wetness forms, including anisotropic and dual-wettability. In this review, cellulose and cellulose-based materials used as an aerogel for oil–water separation are comprehensively reviewed. This review highlights the significance of cellulose and cellulose-based combinations through structure–property interactions, surface modifications (using different hydrophilic and hydrophobic agents), and aerogel formation, focusing on the light density and high surface area of aerogels for effective oil–water separation. This article provides an in-depth review of four primary classifications of cellulose-based aerogels, namely, cellulose aerogels (regenerated cellulose and bacterial cellulose), cellulose with biopolymer-based aerogels (chitosan, lignin, and alginate), cellulose with synthetic polymer aerogels (polyvinyl alcohol, polyetherimide, polydopamine and others), and cellulose with organic/inorganic (such as SiO₂, MTMS, and tannic acid) material-based aerogels. Furthermore, the aspects of performance, scalability, and durability have been explained, alongside potential prospect directions for the advancement of cellulose aerogels aimed at their widespread application. This review article stands apart from previously published review works and represents the comprehensive review on cellulose-based aerogels for oil–water separation, featuring wide-ranging classifications. Full article

This study presents an integrated approach to processing the heavy fraction of coal tar (HFCT) using oil shale (OS) from Shubarkol Komir JSC to simultaneously increase the yield of valuable hydrocarbon fractions and extract rare and dispersed trace elements. The lack of data on the effect of shale on the process and the kinetics of multi-component “tar + shale” systems limits the development of effective technologies. TG/DTG analysis was combined with the Friedman, Ozawa–Flynn–Wall, and Šesták–Berggren methods for the first time to evaluate the role of oil shale (OS). It was shown that the addition of 13% OS provides a sustained reduction in activation energy (~85–86 kJ/mol) and optimal conditions for hydrometallization. At 420 °C, an initial H₂ pressure of 4 MPa, and a reaction time of 60 min, the yield of light fractions reaches 62.6%, and the solid residue concentrates Ti, Mo, Ge, and other rare and dispersed elements reach up to 66,000 g/t in total. The possibility of extracting Ge using the Purolite C100 sorbent has also been confirmed. The novelty of the study lies in demonstrating the donor–catalytic effect of shale and the practical prospects of solid residue as a secondary mineral raw materials. Full article

The efficiency of the sorption–biological method for treatment of oil-polluted coastal substrates (soil and sand) of the Barents Sea under low temperature (10 °C) using the active hydrocarbon-oxidizing bacterial strain Rhodococcus erythropolis HO-KS22 was assessed in the laboratory. The highest rate of hydrocarbon degradation was in sand polluted with a low-density oil emulsion and in soil polluted with a medium-density oil emulsion. Sorption–biological treatment increased the rate of hydrocarbon degradation in sand by 3–4 times during the first month and enhanced the overall efficiency by 20% over a three-month period. The use of sorbents (granular activated carbon, thermally activated vermiculite and peat) both in sand and soil prevents secondary pollution of coastal ecosystems, since it significantly reduces the hydrocarbons’ desorption and their leaching by water. Rhodococcus erythropolis HO-KS22, in combination with sorbents, can be applied during the biological remediation of coastal sandy substrates following the initial removal of emergency oil spills. However, for biological treatment of oil-polluted soils of the Barents Sea coast, further selection of active strains of hydrocarbon-oxidizing bacteria resistant to low pH values and temperatures typical for this region is necessary. The use of microbiological preparations without taking into account the soil and climatic factors of the region may be ineffective, which will increase the cost of remediation of the territory without significantly improving its condition. Full article

Marine oil spills remain a recurring environmental concern, particularly in coastal and estuarine areas. Among the available strategies for managing spilled oil, sorbents derived from natural fibers have attracted considerable interest as viable alternatives to synthetic materials due to their biodegradability, low cost, and alignment with circular economy principles. This review synthesizes recent advances by connecting technical and environmental aspects with operational applications. It emphasizes structural and surface modifications of lignocellulosic fibers to enhance petroleum sorption capacity, selectivity, buoyancy, and reusability. Physical, chemical, and biological approaches are discussed, focusing on how these modifications influence sorption dynamics under realistic conditions. The review also highlights the incorporation of agricultural and industrial residues as raw materials, along with regeneration and reuse strategies that support waste valorization. However, significant gaps remain, such as the lack of studies with weathered crude oils, the limitation of larger-scale testing, and the need for standardized methods and evaluation of the final fate of exhausted biosorbents. Through the integration of technical, environmental, and operational criteria, this review provides a critical foundation for developing more efficient and circular marine oil spill response technologies. Full article

A novel structure–functional-integrated particle featuring dual micromechanical interlocking property with resin matrix was constructed through surface modification of urchin-like serried hydroxyapatite (UHA) in this work, and the effect of this modification strategy on physicochemical and biological properties of dental resin composite was also investigated. A porous silica coating layer was anchored onto UHA surface via a simple template method in an oil−water biphase reaction system, and the coating time had a prominent effect on the coating thickness and morphology-structure of the particle. When these particles with different porous silica coating thickness were used as fillers for dental resin composite, results showed that UHA/PS5 (porous silica coating reaction time: 5 h) exhibited the optimal 3D urchin-like structure and a desirable porous silica coating thickness. Additionally, UHA/PS5 formed the best dual physical micromechanical interlocking structure when mixing with resin matrix, making the dental resin composites presented the desirable matrix/filler interfacial bonding, and the excellent physicochemical–biological properties, especially for flexural strength and water sorption-solubility. In vitro remineralization and cellular biological properties confirmed that the coating layer did not compromise their remineralization activity. The use of UHA/PSx provides a promising approach to develop strong, durable, and biocompatible DRCs. Full article

The development of industry and technology, despite making everyday life easier, generates large amounts of various wastes that negatively affect the environment. Unexpected leaks of substances such as oils, petroleum substances, and chemicals also contribute to the degradation of aquatic and terrestrial ecosystems. Long-term effects of environmental pollution require the development of advanced materials and technologies to collect and neutralize pollutants. Sorbents obtained from waste, including banana peels, coconut fibers, and polyurethane foams from recycling the thermal housing of refrigeration devices, allow a reduction in the amount of generated waste and the development of appropriate sorbents. This work focuses on comparing the sorption and neutralization properties of these materials for two types of oil, machine and diesel, and the possibility of using them in rescue and firefighting operations conducted by firefighters. The results obtained indicate that the viscose–cellulose sorbent and the polyurethane foam sorbent are characterized by better performance parameters than sorbents from coffee grounds or coconut fibers. The best parameters were obtained after the first 10 min of the sorbent–contaminant reaction, whereas in the case of contamination with machine oil, the absorption capacity was better than for diesel oil for each sorbent subjected to analysis. Full article