Search Results (1,030)

Magnetic polymer nanocomposites (MPNCs) have attracted considerable attention as advanced multifunctional materials for water purification due to their high adsorption capacity, magnetic recoverability, and excellent reusability. This review presents a comprehensive overview of recent developments in the synthesis, characterization, and environmental applications of MPNCs for wastewater treatment. Particular emphasis is placed on the principal synthesis strategies, including in situ and ex situ approaches, and their influence on nanoparticle dispersion, interfacial interactions, and the physicochemical properties of the resulting nanocomposites. The review covers the most widely investigated magnetic nanomaterials, such as Fe₃O₄, γ-Fe₂O₃, CoFe₂O₄, ZnFe₂O₄, and other ferrites, incorporated into natural and synthetic polymer matrices including chitosan, cellulose, alginate, polyaniline, polypyrrole, poly(vinyl alcohol), and polystyrene. Advanced characterization techniques, including X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and superconducting quantum interference device (SQUID) measurements, are discussed to evaluate the structural, chemical, thermal, and magnetic properties of these hybrid materials. The adsorption performance and underlying mechanisms of MPNCs for the removal of heavy metals, dyes, pharmaceutical compounds, organic pollutants, and oil contaminants are critically analyzed, highlighting the roles of polymer functionalization, nanocomposite architecture, and magnetic separation in enhancing treatment efficiency and reusability. In addition, the contribution of density functional theory (DFT) to understanding adsorption mechanisms and guiding the rational design of high-performance adsorbents is reviewed. Finally, current challenges and future perspectives, including green synthesis, multifunctional and stimuli-responsive materials, scalable manufacturing, and industrial implementation, are discussed. This review provides a comprehensive framework for the design and development of next-generation magnetic polymer nanocomposites for sustainable water remediation applications. Full article

Cosmetic wastewater is increasingly recognized not only as a disposal problem but also as a potential source of recoverable water and formulation-derived compounds. This review critically examines the relationship between cosmetic formulation chemistry, wastewater composition, pollutant removal mechanisms, membrane separation, fouling behaviour, and reuse-oriented treatment design. Cosmetic wastewater shows high compositional variability, with reported COD values ranging from approximately 2400 mg O₂/L to more than 100,000 mg O₂/L, depending on product type, cleaning practices, and raw material losses. Surfactants, emulsifiers, oils, polymeric thickeners, preservatives, fragrances, UV filters, dyes, and microplastics contribute differently to organic load, emulsion stability, toxicity, and treatment resistance. Conventional treatment processes reduce coarse, suspended, emulsified, and biodegradable fractions, but they are limited by low biodegradability, sludge generation, inhibitory compounds, and incomplete removal of persistent micropollutants. Advanced oxidation, adsorption, electrochemical processes, and hybrid systems can improve the transformation, phase transfer, retention, and polishing of recalcitrant compounds, with AOPs typically achieving COD removal of approximately 55–85% and hybrid systems improving overall performance by about 10–25% compared with biological treatment alone. Membrane technologies are evaluated as selective barriers enabling clarification, polishing, water reuse, and resource recovery. MBRs can remove more than 90–95% of COD and BOD₅, while NF/RO polishing may reject more than 90–95% of selected recalcitrant organics and microcontaminants. The novelty of this review lies in shifting the discussion from end-of-pipe wastewater treatment toward source-oriented recovery, integrated treatment trains, and mechanism-based selection of technologies before cosmetic wastewater becomes diluted, mixed, and difficult to reuse. Full article

Open-surface coalescence of microdroplets is essential for droplet-based microreactors, emulsion processing, and multiphase microfluidics, yet existing methods often require closed channels or patterned electrodes. Here, we report a corona-driven open-oil-film platform that achieves voltage-regulated coalescence of aqueous microdroplets in a simple needle–plate electrode configuration. Positive corona discharge induces coupled electrohydrodynamic effects—including ion transport, interfacial charge redistribution, and Maxwell stresses—that drive oil-film contraction and charge-regulated droplet bouncing, thereby reducing inter-droplet spacing and promoting successive merging. The coalescence rate and final droplet size are tunable via the applied voltage and oil volume: complete coalescence into a single droplet is achieved at 12 kV, and an optimal oil volume of 60 μL maximizes confinement efficiency. To enable quantitative, frame-by-frame analysis, we develop an improved YOLOv5–OC-SORT framework that yields an overall mAP@0.5 of 0.905 for automatic droplet detection and tracking. As a proof-of-concept, the platform achieves electro-demulsification of a surfactant-stabilized water-in-oil emulsion, increasing the average droplet diameter from ~0.005 mm to ~0.2 mm and enabling effective oil–water separation. This work provides a simple, electrode-pattern-free strategy for controllable droplet coalescence and open-surface emulsion breaking. Full article

To address the persistent challenge of membrane wetting during oil-gas separation in transformer condition monitoring, an omniphobic composite membrane was developed to facilitate the reliable online detection of dissolved gases. An F-CNTs/Teflon AF/PVDF composite membrane, featuring a loofah-like hierarchical structure and omniphobic properties, was fabricated via spraying-deposition strategy on the polyvinylidene fluoride (PVDF) substrate. The morphology, surface chemical composition, wettability and stability of the F-CNTs/Teflon AF/PVDF composite membrane were systematically characterized. Subsequently, the oil-gas separation performance of the composite membrane was evaluated using standard transformer oil containing dissolved gases as the feed solution. The results indicated that fluorinated carbon nanotubes (F-CNTs) were successfully modified onto the membrane surface, creating a re-entrant morphology composed of an intersecting nanotube network that mimics the hierarchical architecture of a loofah. The F-CNTs/Teflon AF/PVDF composite membrane exhibited exceptional omniphobicity, achieving contact angles of 168.2 ± 1.5° and 127.5 ± 1.0° towards DI water and mineral insulating oil, respectively. Additionally, the loofah-inspired composite membrane demonstrated robust thermal and ultrasonic stability. In oil-gas separation tests, the omniphobic membrane displayed a rapid response and high efficiency for dissolved gas extraction, achieving dynamic equilibrium within 64 min. Furthermore, the modification improved permeation efficiency by 25.6%. These results suggest that the developed omniphobic membrane is a promising alternative for oil-gas separation in the condition monitoring of oil-filled electrical equipment. Full article

Membrane separation technology has been extensively applied to treat oily effluent given its high performance and ease of operation. However, conventional polymer membranes are resistant to natural degradation after use, leading to severe environmental concerns. Consequently, the development of biodegradable membranes that combine satisfactory oil–water separation performance with ecological safety has emerged as a critical research priority. In this work, we fabricated a biodegradable membrane consisting of chitosan (CS), sodium methacrylate (SMa) and polyvinyl alcohol (PVA) via electrospinning, with anionic super-hydrophilic polyacrylamide (PAM) incorporated to enhance wettability. No toxic chemicals were used throughout the fabrication process. The resulting membrane with an interpenetrating network and beaded structure not only rendered the crosslinked nanofiber more hydrophilic but also improved the porosity of membranes, which significantly enhanced the separation performance and fouling resistance of the membrane. Specifically, the CS/PVA/SMa-PAM membrane achieved a separation flux of 2.7 × 10⁴ L·m⁻²·h⁻¹·bar⁻¹ for oil–water emulsions. After 20 emulsion separation cycles, the flux of the modified membrane was stable at 2.5 × 10⁴ L·m⁻²·h⁻¹·bar⁻¹. Benefiting from its excellent anti-fouling properties, high separation efficiency, eco-friendly biodegradability, and toxic-reagent-free fabrication, the as-prepared CS/PVA/SMa-PAM membrane offers a promising and sustainable option for oily wastewater treatment. Full article

Natural hydrogen is a promising zero-carbon resource, but its small molecular size and high diffusivity make nuclear magnetic resonance (NMR) logging interpretation difficult. This study develops a pore-network and random-walk simulation framework to analyze hydrogen and methane responses in hydrogen-rich sandstones. The model couples pore structure, fluid properties, magnetic-field gradients, and acquisition parameters. Transverse relaxation time (T₂) spectra are inverted with Tikhonov regularization and generalized cross-validation. The effects of waiting time (TW), echo time (TE), pore size, gradient strength, and burial depth are quantified. Results show clear T₂ separation among water, oil, methane, and hydrogen. Dual-TW difference spectra improve fluid discrimination, and hydrogen shows the strongest TW sensitivity. TW mainly controls amplitude, while TE and gradient mainly control diffusion attenuation. Because hydrogen diffuses faster, it is more sensitive than methane to both factors. Greater depth and larger pores shift peaks to longer T₂, but strong diffusion attenuation weakens hydrogen’s pore-size sensitivity. These results clarify the distinct NMR response mechanism of hydrogen. These findings can directly support NMR logging workflows for natural hydrogen reservoir identification by guiding TW–TE parameter design and gradient control, and by improving H₂-CH₄ discrimination in mixed-gas intervals. They can also reduce interpretation uncertainty in deep, heterogeneous formations, thereby improving confidence in identifying and evaluating natural hydrogen reservoirs. Full article

Emulsified oily wastewater from industrial activities remains challenging to treat because kinetically stable oil droplets hinder efficient separation, threatening water resources and ecological environments. To address this issue, this work develops an inclined solar-driven evaporator based on a polypyrrole (PPy)-coated bacterial cellulose (BC) gel (PPy-BC gel), which has enlarged effective evaporation areas and an environmental heat effect. Under one sun (1 kW m⁻² under standard solar illumination), the PPy-BC gel achieves an evaporation rate of 2.14 kg m⁻² h⁻¹, which is 494% higher than that of the uncoated BC gel. In diesel-in-water emulsions with oil concentrations ranging from 0 to 15 vol%, the gel maintains stable evaporation performance, achieving an oil removal efficiency exceeding 99% across all tested concentrations. After 15 consecutive cycles of treating actual oily wastewater, no significant performance degradation is observed. The collected condensate exhibits excellent water quality, with removal efficiencies for total organic carbon (TOC), chemical oxygen demand (COD), and total dissolved solids (TDS), and ionic conductivity (IC) exceeding 94%. This work presents a solar-powered evaporation platform, which demonstrates potential in the stable treatment of complex oily wastewater, and offers a sustainable reference solution for decentralized industrial wastewater management. Full article

This work introduces a Targeted Emulsified-Solvent Injection (TESI) process for extracting bitumen from oil sands. In TESI, a solvent is emulsified near the emulsion phase inversion point (PIP), where the interfacial tension and the emulsion stability are very low. This allows the solvent to be easily emulsified and then deposited onto the bitumen-coated porous media (under lower shear conditions, where the emulsion breaks), mixing with bitumen, decreasing bitumen viscosity, and enabling mobilization and diluted bitumen recovery. The design of the surfactant-solvent formulation was guided by the Hydrophilic-Lipophilic-Difference and Net-Average-Curvature (HLD-NAC) frameworks. The HLD-NAC was used to identify a formulation with less than 1% surfactant exhibiting ultralow interfacial tension (~10⁻³ mJ/m²), at the PIP, where HLD = 0. This formulation was injected into columns packed with bitumen-coated sands at varying salinities and water-to-solvent ratios. Using optimal conditions, bitumen recoveries of up to 83% can be obtained at room temperature, without the need for steam or high-pressure injection, a condition suitable for intermediate-depth reservoirs. The effluent emulsion of diluted bitumen can be gravity-separated, allowing for the recycling of the aqueous solution containing the surfactant. The recovery curves were modeled using a continuous stirred tank reactor (CSTR) model coupled with a Capillary number model for thin viscous films that allowed the prediction of effluent diluted bitumen viscosities and an estimation of the pressure drops in the column that were consistent with experimental observations. Full article

Urushiol, the main active compound in raw lacquer, is a catechol derivative with long alkyl side chains. Its use in traditional coatings has long been held back by slow enzymatic curing, UV sensitivity, and its own allergenicity. Over the past decade, greener ways to extract it have emerged—ultrasound- and microwave-assisted methods, plus vortex-assisted matrix solid-phase dispersion and ball-milling-enhanced microextraction. These approaches have been shown to recover urushiol efficiently, using less solvent and lowering operator risk. The catechol structure explains its many uses: fast-curing UV coatings that resist corrosion, antibacterial materials (both plain and metal-coordinated), superwetting surfaces for oil–water separation, and selective uptake of heavy metals and rare-earth ions. Early biomedical work also hints at its potential as a bioactive scaffold, drug carrier, or low-toxicity starting point. To balance performance and safety, multiple strategies have been proposed to reduce allergenicity: protecting the hydroxyl groups, modifying specific sites on the ring, and designing synthetic mimics. Still, a few bottlenecks are holding back industrial scale-up. These include large-scale green extraction, long-term material stability, and the lack of solid biocompatibility data. Future work needs to integrate three core research directions: high-throughput structure–activity–toxicity screening, cross-disciplinary molecular design, and life-cycle assessment. The integrated development of these three directions will facilitate the industrial transformation of urushiol-based materials from laboratory prototypes to high-value commercial products. This review summarizes and outlines a roadmap for green extraction, functional polymer applications, and the safe use of urushiol. Full article

This study presents a green approach for polyethylene terephthalate (PET) upcycling using a biphasic system of subcritical water and castor oil. This system enables efficient conversion without an external catalyst and facilitates product separation. Hydrolysis of castor oil generates fatty acids in situ, which catalyze PET conversion to selectively produce low-molecular-weight oligoesters (Mn ≈ 1500 g/mol). These oligoesters are inherently immiscible with the bio-medium at room temperature, allowing straightforward separation by centrifugation. Orthogonal experiments show that temperature is the dominant factor affecting PET conversion, with the optimal conditions being 200 °C, a water-to-oil mass ratio of 1:5, and a reaction time of 10 h for complete conversion. Under the practical optimum condition, the castor oil phase remained highly effective over five consecutive depolymerization cycles. The functionalized oligoesters were used in polyurethane synthesis. At 6% loading, they gave adhesives with a T-peel strength of 8.09 N/15 mm and tensile strength of 25.14 MPa, and excellent damp-heat stability (only 0.62% loss in T-peel and 0.47% in 180° peel after aging). Thermogravimetric analysis confirmed enhanced thermal stability, with increases of 19.52 °C in T_5% and 16.50 °C in T_50% compared with the unmodified system. These results demonstrate the practical potential of the obtained oligoesters in high value adhesive applications. Full article

The growing deployment of green hydrogen technologies is increasing pressure on freshwater resources, motivating the exploration of alternative water sources that do not compete with human consumption. In this work, the direct use of untreated produced water from the Shushufindi 78 oil well (Ecuador) as an electrolyte for the hydrogen evolution reaction (HER) was experimentally evaluated. A comprehensive physicochemical characterization combined with electrochemical techniques, electrochemical impedance spectroscopy (EIS), and gas chromatography (GC-TCD) was performed to correlate electrolyte composition with electrochemical performance. Despite the high salinity and complex composition of the electrolyte, hydrogen production was achieved without pretreatment. Quantitative GC-TCD analysis yielded 10.29 µmol of H₂ after 4 h of electrolysis under non-optimized laboratory conditions, corresponding to a faradaic efficiency of 43.8%. These results demonstrate the feasibility of direct hydrogen generation from untreated produced water under realistic operating conditions. Additional experiments conducted in a membrane separated H-type electrolyzer evaluated mixtures of produced water and KOH, the electrolyte commonly employed in alkaline water electrolysis. Hydrogen production increased significantly under alkaline conditions, with the PW 10% + KOH 90% electrolyte exhibiting the highest hydrogen yield and faradaic efficiency among the investigated systems. Electrochemical impedance spectroscopy revealed that KOH addition reduced solution resistance and improved ionic transport, while differences in interfacial behavior were observed depending on electrolyte composition. The combined electrochemical and chromatographic results demonstrate that untreated produced water can be directly utilized for hydrogen production and can also be partially integrated into alkaline electrolysis systems without compromising electrochemical performance. These findings highlight the potential of produced water as a non-conventional water resource for sustainable hydrogen generation and industrial wastewater valorization. Full article

Sophorolipids (SLs) produced from Starmerella bombicola using four different secondary substrates such as refined, bleached, and deodorized palm olein (RBD PO), RBD palm kernel olein (RBD PKO), RBD coconut olein (RBD CO) and fatty acid methyl ester (FAME) waste are reported. Their interfacial characteristics at medium-chain triglyceride (MCT) oil-water interface and ability to form nano/submicron emulsions were studied. The effects of SLs from different sources, SL concentrations and blend ratios of SLs and soybean lecithin on characteristics of emulsions produced by ultrasonication were examined. Initially, emulsion formed using SLs coded (from F2 to F5) showed large droplets (d₃₂ > 1000 nm) and poor stability. They were then blended with soybean lecithin at a ratio of 3:1 to produce emulsions coded F6 to F9 with smaller droplets (d₃₂ < 400 nm) and great stability over a range of temperatures (from 40 °C to 90 °C) and pH values (from 3 to 9). However, highly acidic (pH 2) and low ionic strength (1 mM NaCl) processing caused the separation of the emulsions. These emulsions also displayed potential antimicrobial activities towards Bacillus cereus and Pseudomonas aeruginosa, as well as cytotoxic effects against the human epithelial colorectal adenocarcinoma cell line (Caco-2). These results illustrated that stable emulsions required a mixture of SLs and soybean lecithin. Full article

Laser micro/nanoprocessing has emerged as an effective strategy for the fabrication of superhydrophobic and superamphiphobic surfaces owing to its high precision, broad material compatibility, and flexible processing capability. This review systematically summarizes recent advances in laser-based fabrication of functional wetting interfaces. The two primary processing pathways, laser ablation and laser-induced structuring, are comparatively discussed, with emphasis on the processing–structure–property relationships of metallic, polymeric, and ceramic substrates. Representative applications, including anti-icing and anti-frosting, anti-fogging, corrosion resistance, oil–water separation, and antibacterial surfaces, are further reviewed to highlight the engineering potential of laser-fabricated superhydrophobic interfaces. Despite significant progress, challenges related to processing efficiency, long-term durability, fabrication cost, and process controllability remain. Future research is expected to focus on intelligent process optimization, high-throughput manufacturing, environmentally friendly modification strategies, and multifunctional integration, thereby accelerating the transition of laser-fabricated superhydrophobic surfaces from laboratory research to large-scale industrial applications. Full article

Hydrophobic and superhydrophobic surfaces have emerged as key solutions for fluid transport, biofouling prevention, and energy efficiency, with market forecasts projecting a compound annual growth rate (CAGR) of over 15% through 2030 due to their broad range of applications. This review critically examines the principles of natural hydrophobicity, as exemplified by lotus leaves and shark skin, and their translation into engineered surfaces via micro/nanofabrication techniques, such as laser patterning, etching, and self-assembly. Recent advances in hybrid nanomaterials have demonstrated WCAs in the range of 140–160°, along with enhanced mechanical strength and chemical stability, enabling applications in self-cleaning, anti-corrosion, and oil–water separation technologies. Superhydrophobic coatings are particularly important for reducing ice adhesion by more than 80%, while drag reduction in pipelines can reach up to 30%, contributing to energy savings. Despite these advances, challenges remain in achieving long-term stability under harsh environmental conditions, minimizing environmental impact, and developing cost-effective, scalable fabrication techniques. Future directions focus on environmentally friendly, multifunctional nanocomposites with switchable wettability, including pH- and light-responsive coatings capable of reversibly transitioning between superhydrophilic (<5°) and superhydrophobic (>150°) states, paving the way for sustainable and adaptable surface technologies. Full article

Multifunctional membranes capable of simultaneously separating oil–water emulsions and removing organic dyes from complex aqueous systems have garnered considerable attention in recent years. However, the facile fabrication of high-performance membranes that integrate both separation and adsorption functions remains a significant challenge. Herein, we report the fabrication of a polyacrylonitrile/polyvinyl alcohol–chitosan (PAN/PVA-CS) bilayer membrane with asymmetric wettability via electrospinning. The micro/nanostructures and surface wettability of the as-prepared membranes were precisely tailored by modulating the chitosan (CS) concentration. The resultant PAN/PVA-CS membrane exhibited an overall separation efficiency exceeding 97.5% for mechanically emulsified samples. Notably, the PVA-CS layer demonstrated superhydrophilicity and excellent underwater oleophobicity, enabling the gravity-driven simultaneous separation of oil-in-water emulsions and adsorption of water-soluble Congo red dye without requiring external pressure. The maximum adsorption capacity for Congo red reached 61.3 mg g⁻¹, surpassing that of numerous reported membrane-based and adsorbent materials. Concurrently, the hydrophobic PAN layer in the bilayer structure enabled the separation of water-in-oil emulsions. Overall, this work provides a promising strategy for the rational design of asymmetrically wettable multifunctional membranes with great potential for practical application in the purification of complex industrial wastewater containing both emulsified oils and soluble organic dyes. Full article