Search Results (69)

The increasing incidence of oil contamination in many aquatic ecosystems, particularly in oil-rich regions such as Qatar, poses significant threats to marine life and human activities. Our study addresses the critical need for effective and eco-friendly oil-water separation techniques, focusing on developing graphene and chitosan-based three-dimensional (3D) polymeric sponges. These materials have demonstrated potential due to their high porosity and surface area, which can be enhanced through surface treatment to improve hydrophobicity and oleophilicity. This study introduces a new technique dependent on the optimization of the graphene oxide (GO) concentration within the composite sponge to achieve a superior oil uptake capacity (51.4 g oil/g sponge at 3% GO), and the detailed characterization of the material’s performance in separating heavy oil-water emulsions. Our study seeks to answer key questions regarding the performance of these modified sponges and their scalability for industrial applications. This research directly aligns with Qatar’s environmental goals and develops sustainable oil-water separation technologies. It addresses the pressing challenges of oil spills, ultimately contributing to improved marine ecosystem protection and efficient resource recovery. Full article

Oil–water separation is an important method for treating oily wastewater and recovering oil resources. Based on the different affinities of superhydrophobic surfaces to water and oil, long-term oil–water separation devices with low-energy and high efficiency can be developed through the optimization of structure and process parameters. Superhydrophobic coatings were prepared on stainless-steel mesh surfaces using a spray method to construct single-channel oil–water separation equipment with superhydrophobic/oleophilic meshes, and the effects of structural and process parameters on separation efficiency were systematically investigated. Additionally, a multi-channel oil–water separation device was designed and fabricated to evaluate the feasibility and stability of long-term continuous operations. The optimized single V-shaped channel should be horizontally placed and made from 150-mesh stainless-steel mesh folded at an angle of 38.9°. For the oil–water mixtures containing 20 wt.% oil, the oil–water separation efficiencies for single and two-stage separation were 92.79% and 98.96%, respectively. After 36 h of continuous operation, the multi-channel separation device achieved single-stage and two-stage separation efficiencies of 94.60% and 98.76%, respectively. The maximum processing capacity of the multi-channel device reached 168 L/h. The modified stainless mesh can remain stable with a contact angle (CA) higher than 150° to water for 34 days. The average residence time and contact area during the oil–water separation process significantly affect separation efficiency. By optimizing oil–water separation structures and process parameters, and using a superhydrophobic spray modification method, separation efficiency can be improved while avoiding the generation of secondary pollutants. Full article

During oilfield production, organic substances such as asphaltenes and resins present in crude oil are prone to adsorb onto the surfaces of reservoir rocks. This adsorption process can lead to the conversion of hydrophilic rock surfaces into more oleophilic interfaces, which in turn reduces the permeability and porosity of the reservoir, ultimately affecting the overall recovery efficiency. Consequently, targeted modification of reservoir wettability presents a promising strategy for enhancing recovery rates. In this study, a polymer layer comprising large molecular side chains and hydroxyl groups was synthesized on the surface of nano-SiO₂ to enhance the thermal stability of the polymer. Additionally, the hydroxyl groups were employed to improve the wettability of the core material and reduce interfacial tension. The polymers were characterized using techniques such as FTIR and TG, and the results revealed that the modified SiO₂ exhibited superior performance in reducing both interfacial tension and contact angle when compared to the SiO₂. Injection of a 0.4 wt% EP-HMTA-SiO₂ solution resulted in an increase in recovery rates by 16.4% and 13.2% in medium- and low-permeability cores, respectively. Full article

Due to the high viscosity and low fluidity of viscous crude oil, how to effectively recover spilled crude oil is still a major global challenge. Although solar thermal absorbers have made significant progress in accelerating oil recovery, its practical application is largely restricted by the variability of solar radiation intensity, which is influenced by external environmental factors. To address this issue, this study created a new composite fiber that not only possesses solar energy conversion and storage capabilities but also facilitates crude oil removal. PF@PAN@PEG was obtained by coaxial electrospinning processing, with PEG within PAN fibers, and a coating layer was applied to the fiber surface to impart oleophilicity and hydrophobicity. PF@PAN@PEG exhibited a high latent heat value (77.12 J/g), high porosity, and excellent photothermal conversion and oil storage capabilities, significantly reducing the viscosity of crude oil. PF@PAN@PEG can adsorb approximately 11.65 g/g of crude oil under sunlight irradiation. Notably, due to the encapsulation of PEG, PF@PAN@PEG can continuously maintain the crude oil at a phase change temperature by releasing latent heat under specific conditions, effectively reducing its viscosity with no PEG leakage at all. When solar light intensity varied, the crude oil collection efficiency increased by 21.99% compared to when no phase change material was added. This research offers a potential approach for the effective use of clean energy and the collection of viscous crude oil spill pollution. Full article

In this work, the simple fabrication of a new superhydrophobic magnetic sponge based on CNTs, NiFe₂O₄ nanoparticles, and PDMS was investigated. CNTs were synthesized by chemical vapor deposition (CVD) on a nickel ferrite catalyst supported on aluminum oxide (NiFe₂O₄/Al₂O₃). The synthesis of nickel ferrite (NiFe) was accomplished using the sol–gel method, yielding magnetic nanoparticles (43 Am²kg⁻¹, coercivity of 93 Oe, 21–29 nm). A new superhydrophobic magnetic PU/CNT/NiFe₂O₄/PDMS sponge was fabricated using a polyurethane (PU) sponge, CNTs, NiFe₂O₄ nanoparticles, and polydimethylsiloxane (PDMS) through the immersion coating method. The new PU/CNT/NiFe₂O₄/PDMS sponge exhibits excellent superhydrophobic/oleophilic/mechanical properties and water repellency (water absorption rate of 0.4%) while having good absorption of oil, olive oil, and organic liquids of different densities (absorption capacity of 21.38 to 44.83 g/g), excellent separation efficiency (up to 99.81%), the ability to be reused for removing oil and organic solvents for more than 10 cycles, and easy control and separation from water using a magnet. The new PU/CNT/NiFe₂O₄/PDMS sponge is a promising candidate as a reusable sorbent for collecting oil and organic pollutants and can also be used as a hydrophobic filter due to its excellent mechanical properties. Full article

Accurately describing the behavior of a gas-water two-phase flow in shale gas reservoirs is crucial for analyzing production dynamics in the field. Current research generally lacks consideration of the differences in physical properties and adsorption characteristics between the oleophilic organic matrix and the hydrophilic inorganic matrix. This study considers the organic matrix system as a single-phase gas flow, while the inorganic matrix and fracture systems involve a gas-water two-phase flow. Taking into account the impact of the adsorbed water layer on permeability at the surface of nanoscale pores in an inorganic matrix, the model comprehensively incorporates multiple mechanisms such as adsorption-desorption, the slippage effect, and Knudsen diffusion in the organic matrix and clay minerals. A multiscale gas-water two-phase comprehensive flow model for shale gas reservoirs has been established, and the results of the numerical model were validated against commercial software and actual field data. Simulation results over 1000 days indicate that early production from gas wells is primarily supplied by fractures, whereas free gas or desorbed gas from inorganic and organic matrices gradually contributes to the flow during the middle and later stages of production. As the Langmuir pressure and volume in the organic matrix and clay minerals increase, so does the corresponding gas production. The adsorbed water layer on the surface of inorganic nanopores reduces permeability, leading to a decrease in single-well cumulative gas production by 8.41%. The impact of the adsorbed water layer on gas production cannot be overlooked. The simulation method proposed in this study provides theoretical support for analyzing the gas-water two-phase flow behavior in shale gas reservoirs. Full article

In this study, a three-dimensional (3D) porous sponge capable of oil–water separation was fabricated using recycled expanded polystyrene (EPS) through 3D electrospinning, by adding phosphoric acid to the electrospinning solution. The fabrication process was a rapid and efficient single-step process to produce the 3D sponge. In addition, the additive’s concentration was also optimized for oil absorption. The fabricated EPS sponge was highly effective in oil–water separation due to its excellent hydrophobic and oleophilic properties. This demonstrates its potential as a sustainable and efficient absorbent to address ongoing oil pollution issues. Moreover, the performance of the recycled EPS sponge was found to be comparable to that of sponges made from virgin polystyrene, suggesting the feasibility of using recycled materials for the production of high-value products. This research presents an efficient method for fabricating 3D sponges from recycled materials, contributing to environmental protection and resource recycling. Full article

In this study, we demonstrate a new all bio-based adsorbent material by treating Enteromorpho prolifera (EP) fibers with tannic acid-ferric chloride complex and then grafting hydrophobic group octadecylamine. All raw materials are easily available, low-cost, and safe. The modified EP fibers have approximately 63.4 g ${\mathrm{g}}^{-1}$ of oil absorption and 1.4 g ${\mathrm{g}}^{-1}$ of water absorption, which is an 62.8% increase in oil absorption and an 82% increase in hydrophobicity over that of untreated EP fibers, respectively, exhibiting high hydrophobicity and oleophilicity. The affinity discrimination to water and oil enables hydrophobic algae candidate materials to separate oils and water efficiently, both in an oil–water mixture and a water-in-oil emulsion. In summary, the as-synthesized modified EP demonstrates a broad application prospect in the treatment of oil spill accidents and oily wastewater. Full article

The study aims to eliminate the effect of coalescing filter blocking due to on–off operation by changing the wetting properties of the non-woven fiberglass filter media through their chemical modification with the use of a polydimethylsiloxane (PDMS) solution in hexane and a few commercial products that give the surface oleophobic properties. The best results—high separation efficiency, no redispersion of droplets at the outlet, and low flow resistance—were obtained for materials coated by immersion in a 0.2% PDMS solution, for which a reduction in oleophilicity was found, but the material was not oleophobic and still moderately wetted with the test liquid. The corresponding static contact angle with the VG-46 rotary compressor oil measured on the flat borosilicate glass wafer made of the same material as the fiberglass media was equal to 54° for the PDMS dip-coated surface. Moreover, the good stability of the applied polymer on the material surface was confirmed by the SEM imaging, the FTIR analysis, and maintaining a high performance in multiple tests run for a single coalescing element. Full article

Fiber-based sorbent materials are an essential part of containing oil spills, thus preventing ecological damage. Poly(styrene-b-isobutylene-b-styrene) thermoplastic elastomer fibers were successfully produced by centrifugal spinning. Scanning electron microscopy revealed that the fibers were bead free and smooth-surfaced, with an average fiber diameter of 5.9 ± 2.3 μm. Contact angle measurements proved the highly hydrophobic (water contact angle of 126.8 ± 6.4°) and highly oleophilic nature of the fiber mat. The sorption and retention capacities of the fiber mat were tested for various oils and benchmarked against polypropylene as the industry standard and polystyrene, which is widely used in the literature. The oil uptake of the fiber mat showed a strong correlation with the viscosity of the oil, resulting in sorption capacities of 10.1 ± 0.8 g/g for sunflower oil, 19.9 ± 2.1 g/g for motor oil, and 23.8 ± 1.8 g/g for gear oil. Oil–water separation tests were also conducted, resulting in ~100% oil removal. The thermoplastic elastomer fiber mat outperformed the industry standard; however, the polystyrene fiber mat demonstrated the best oil sorption performance. Full article

The production of value-added products from microorganisms, such as single-cell protein (SCP), through the valorization of agricultural byproducts enhances circular economy while offering alternative solutions for waste treatment. In this study, SCP was obtained through the biotechnological treatment and valorization of cheese whey, the main byproduct of the dairy industry, for the development of novel edible films. To the best of the authors’ knowledge, this is the first report examining SCP as a biopolymer for edible film production. Specifically, Kluyveromyces marxianus, which has gained QPS and GRAS status, strain EXF-5288 cultivated in deproteinized cheese whey (DCW) lactose (10.0 g/L) in a 3 L fed-batch bioreactor, resulting in a SCP_max of 2.63 g/L with a protein content of up to 49.1% w/w. The addition of increased glycerol concentrations (30, 40, and 50% w/w of dry cells) as plasticizers was examined to develop SCP-based edible films. Regarding physicochemical characterization, increased glycerol concentration significantly increased moisture content (MC%) and solubility (S%), but there was not a significant difference in other parameters. Regarding wettability, SCP-based films could be described as oleophilic surfaces since the degree of oil contact angle (OCA) ranged between 46.7° ± 1.3 and 54.0° ± 0.5. The proposed holistic approach could contribute to the development of sustainable packaging materials through waste treatment. Full article

The aim of this study was a systematic analysis of the influence of anions (chloride and sulfate) on the electrochemical behavior of the Co-Sn system during codeposition from gluconate baths. The pH-dependent multiple equilibria in cobalt–tin baths were calculated using stability constants. The codeposition of the metals was characterized thermodynamically considering the formation of various Co_xSn_y intermetallic phases. The alloys obtained at different potentials were characterized in terms of their elemental (EDS and anodic stripping) and phase compositions (XRD), the development of preferred orientation planes (texture coefficients), surface morphology (SEM), and wettability (water; diiodomethane; surface energy). The mass of the deposits and cathodic current efficiencies were strongly dependent on both the deposition potential and the bath composition. The morphology and composition of the alloys were mainly dependent on the deposition potential, while the effect of the anions was less emphasized. Two-phase alloys were produced at potentials −0.9 V (Ag/AgCl) and lower, and they consisted of a mixture of tetragonal tin and an uncommon tetragonal CoSn phase. The preferential orientation planes of tin grains were dependent on the cobalt incorporation into the deposits and anion type in the bath, while the latter did not affect the preferential orientation plane of the CoSn phase. The surface wettability of the alloys displayed hydrophobicity and oleophilicity originating from the hierarchical porous surface topography rather than the elemental or phase composition. The codeposition of the metals occurs within the progressive nucleation model, but at more electronegative potentials and in the presence of sulfate ions, a transition from progressive to instantaneous nucleation can be possible. This correlated well with the partial polarization curves of the alloy deposition and the texture of the tin phase. Full article

Oil-degrading bacteria have the ability to degrade alkanes present in crude oil because of a special enzymatic system, the alkane hydroxylase complex (AlkH). The mechanism for the transport and degradation of alkanes present in crude oil remains unclear, especially related to the first step in hydrocarbons oxidation. In this work, we present a novel model of the crude oil biodegradation mechanism by considering the contact between the oil drop and the cell and calculating the mass transfer coefficients in three oleophilic bacteria (B. licheniformis, P. putida and P. glucanolyticus). The mass transfer coefficients are evaluated under critical time conditions, when the kinetics and mass transport are in balance, and the difference in the values obtained (k_L α = 1.60 × 10⁻³, 5.25 × 10⁻⁴ and 6.19 × 10⁻⁴ m/d, respectively) shows the higher value of the mass transfer coefficient and higher biodegradation potential for B. licheniformis. Because the morphology of the cells has been analyzed by optical and electron microscopy, in the proposed model, the increase in the size of the cells in P. glucanolyticus compared to P. putida exhibits higher values of the mass transfer coefficients and this is attributed, as a novel statement, to a bigger window for alkanes transport (contact area) when the external area of the cell is bigger. Full article

Environmental pollution caused by microplastics has evolved into a global concern; however, limited knowledge exists about microplastics in soils due to the absence of standardized extraction methods. This research aimed to develop an inexpensive, rapid method with user-friendly and environmentally sustainable outcomes for microplastics retrieval. Three salt solutions (Sodium Chloride, Magnesium Sulfate, Sodium Hexametaphosphate) and an oil solution (canola oil) underwent evaluation for microplastics extraction through the flotation process due to the density and oleophilic properties of plastics. Four widely used plastic types, obtained through fragmentation using a grinding mill from clean new plastic containers or membranes, were subjected to analysis. The experimental procedures for microplastics retrieval varied among the evaluated solutions. Through a comprehensive multicriteria analysis, the saturated Sodium Chloride solution emerged as the optimal scenario for microplastics extraction, followed closely by the canola oil scenario. The recovery method utilizing Sodium Chloride demonstrated economic feasibility, safety, and reliability. This study provides valuable insights into an effective and sustainable approach for mitigating microplastic pollution in soil, offering a promising avenue for future environmental conservation efforts. Full article

Recycling low-end, one-time-use plastics—such as low-density polyethylene (LDPE)—is of paramount importance to combat plastic pollution and promote sustainability in the modern green economy. This study valorizes LDPE waste by transforming it into 3D oleophilic swellable thin films through a process involving dissolution, phase separation, and extraction. These films are subsequently layered using a customized polypropylene (PP) based nonwoven fabric separator and securely sealed in a zigzag pattern. The zigzag-shaped seal enhances the adhesion of pollutants to the sorbent by providing wire curvatures that increase retention time and uptake capacity. As a result, the sorbent exhibits impressive oil uptake capacities, with immediate and equilibrium values of 120 g/g and 85 g/g, respectively. Notably, the as-prepared sorbent demonstrates low water retention and high selectivity for oil, outperforming commercially available oil sorbents. The unique design involving a 3D-film structure, superposed films, and a zigzag-shaped seal offers a sustainable and value-added solution to the issues of LDPE waste and oil spills on water surfaces. Full article