Construction of superhydrophilic/underwater superoleophobic polydopamine‐modified h‐BN/poly(arylene ether nitrile) composite membrane for stable oil‐water emulsions separation

Oil/water emulsion separation in harsh environments remains a big challenge. Herein, a double layered nanofibrous composite membrane was developed by assembly of polydopamine‐modified hexagonal boron nitride (h‐BN‐PDA) onto a poly(arylene ether nitrile) (PEN) nanofibrous mat. Owing to the synergistic effect of a h‐BN‐PDA skin layer and a PEN nanofibrous mat supporting layer, as‐prepared composite membrane exhibited high thermal stability, corrosion resistance, and superhydrophilic/underwater superoleophobic property. Consequently, the PEN composite membrane showed good antifouling performance and a high rejection ratio (>99.0%) for various oil/water emulsions. After 10 cycles, the separation flux of PEN composite membrane still reached 588.1 L/m² h under the operating pressure of 0.04 MPa. Furthermore, the PEN composite membrane could still achieve high separation efficiency and high flux in high‐temperature (65 °C) and strongly corrosive conditions (pH = 1‐13). Therefore, the stable and efficient h‐BN‐PDA/PEN composite membrane showed potential application for treating oily wastewater in harsh environments.     

Controllable wettability of laser treated aluminum mesh for on-demand oil/water separation

Oil/water separation has attracted more attention with the dramatic increasing of oil spill accidents and arbitrarily discharged oily industrial water. However, many reported materials with controllable wettability for on-demand oil/water separation of both heavy and light oil/water mixtures involve complicated devices and dangerous fabrication processes. Herein, we propose a simple, environmentally friendly and high-efficient method to fabricate Al mesh with controllable wettability. Heavy oil can be separated with a high efficiency of 99% in oil-removing mode. For light oil, the separation efficiency can also reach up to 99% in water-removing mode. Additionally, surface wettability of the mesh can be conversed from superhydrophobicity to superhydrophilicity by atmospheric pressure plasma jet (APPJ) and heating, thereby realizing continuous bidirectional separation. Therefore, this work provides a facile, green, and efficient way for on-demand oil/water separation and finds a promising solution for oil pollution problems.     

Facile creation of superoleophobic and superhydrophilic surface by using perfluoropolyether dicarboxylic acid/silica nanocomposites

Perfluoropolyether dicarboxylic acid [HO(O?)CCF(CF₃){OCF₂CF(CF₃)}_nO(CF₂)₅O{CF(CF₃)CF₂O}_m―CF(CF₃)C(?O)OH; n + m = 6–12; PFPE‐DAcD] was applied to the preparation of PFPE‐DAcD/SiO₂ nanocomposites by the sol–gel reactions of the corresponding diacid with tetraethoxysilane in the presence of silica nanoparticles under alkaline conditions. PFPE‐DAcD/SiO₂ nanocomposites thus obtained were found to exhibit a good dispersibility and stability in not only water but also the traditional organic solvents such as methanol, ethanol, 2‐propanol, tetrahydrofuran, and 1,2‐dichloroethane. Field emission scanning electron micrograph (FE‐SEM) and dynamic light‐scattering (DLS) measurements show that these fluorinated composites are nanometer size‐controlled very fine particles. Dodecane and water contact angle measurements on the modified glass, filter paper, and polyester fabric surfaces treated with these fluorinated nanocomposites were found to exhibit the superoleophobicity and superhydrophilicity. Especially, the modified polyester fabric swatch was applied to the oil/water separation to give the high separation efficiency. Copyright © 2015 John Wiley & Sons, Ltd.     

Durable,water-cleanable,superhydrophilic coatings for oil/water separation under harsh conditions

A simple, economical, and efficient method for fabricating stable hydrophilic/underwater superoleophobic coating under harsh conditions remains a significant challenge. Here, by the hydrolysis of 3-(Methacryloyloxy) propyltrimethoxysilane (TMSPMA) on cotton fabric and the free radical polymerization of [2-(Methacryloyloxy) ethyl] dimethyl-(3-sulfonic acid propyl) ammonium hydroxide (SBMA) and TMSPMA, a superhydrophilic coating was fabricated. The coating can withstand harsh environments, such as strong acid and alkali. In addition, the coated cotton fabrics show an effective separation of surfactant-stabilized oil-in-water emulsions with extreme flux as high as 1500 Lm^?2 h^?1 only under gravity. Importantly, the oil-contaminated coated cotton fabrics can be cleaned only by water washing. The outstanding properties of the coating including durability, recyclability and resistance to harsh environment, highlight its practical application in emulsion separation and oily wastewater purification.     

Straightforward Oxidation of a Copper Substrate Produces an Underwater Superoleophobic Mesh for Oil/Water Separation

A superhydrophilic and underwater superoleophobic Cu(OH)₂‐covered mesh with micro‐ and nanoscale hierarchical composite structures is successfully fabricated through a one‐step chemical oxidation of a smooth‐copper mesh. Such mesh, without any further modification, can selectively separate water from oil/water mixtures with high separation efficiency, and possess excellent stability even after 60 uses. This method provides a simple, low‐cost, and scalable strategy for the purification of oily wastewater.     

Fabrication of superhydrophobic sponge with hierarchical structure and application for oil/water separation

Oil/water separation polyurethane sponge with hierarchically structured surface similar to the chemical/topological structures of lotus leaf has been successfully developed by combining mussel-inspired one-step copolymerization approach. The chemical structure, surface topography, and surface wettability of the sponge were characterized by FTIR, SEM, and contact angle experiments, respectively. The results showed that as-prepared sponge exhibited high oil absorption rate because of the expansion in oil and collapse in water of the polymer molecular brushes. Meanwhile, it also possessed high absorption capacity (20 times of the self-weight), high oil retention (93.7%), and good recyclability. It had excellent potential in practical applications.     

Recent developments in polymeric superoleophobic surfaces

The construction and application of superoleophobic surfaces have aroused worldwide interest during the past few years. These surfaces are of great significance not only for fundamental research but also for various practical applications in self‐cleaning, oil‐repellent coatings, and antibioadhesion. The unique properties of polymers have made them one of the most important materials for constructing superoleophobic materials. This article reviews recent developments in the design, fabrication, and application of polymeric superoleophobic surfaces. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

超亲水超疏油油水分离膜的制备及其性能

超亲水-超疏油油水分离膜是一种过水隔油的特殊分离膜,在处理海洋溢油污染、环境含油废水时具有保持分离膜不被油污染的优势,有十分重要的实际意义。为了掌握近年来超亲水超疏油分离膜的发展动态,本文首先以液体静压力与毛细作用力为基础阐述亲水疏油膜的油水分离机理;然后分类概括超亲水-超疏油金属基底网膜、刺激响应油水分离膜、无基底聚合物膜材料的制备及各项性能的研究新进展;最后总结目前在该领域仍存在的问题并进行展望。     

Preparation of emulsion‐templated fluorinated polymers and their application in oil/water separation

A series of emulsion‐templated fluorinated polymers (polyHIPEs) were first synthesized with introducing 2‐(perfluorohexyl)ethyl methacrylate (PEM) to the external phase of water‐in‐styrene high internal phase emulsion (HIPE) templates. The morphology (i.e., void size and its distribution) of these porous materials could be tuned simply by changing PEM and/or surfactant amount. The synergistic effect between the surface chemistry and surface architecture allowed the polyHIPEs to possess hydrophobicity with a water contact angle of 151°. The superhydrophobicity and oleophilicity of the polyHIPEs, together with their highly open porous structure, make the material a very competitive candidate as a filtration material for oil/water separation in practice with the efficiency of separating dichloromethane from the oil/water mixture of 95%. Such oil/water separating capacity was maintained after 10 cycles of filtration of oil/water, indicating the cyclic usage of the polyHIPE is feasible. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1508–1515     

Facile fabrication of superhydrophobic SiO2-coated mesh used for corrosive and hot water/oil separation

Journal of Sol-Gel Science and Technology - Oil pollution has been a worldwide problem. Most of the superhydrophobic materials lose their superhydrophobicity when exposed to hot water (e.g.,...     

Robust superhydrophobic surface fabrication by fluorine-free method on filter paper for oil/water separation

Robust superhydrophobic surface exhibiting anti-fouling and self-cleaning ability were successfully fabricated by nano TiO2 modified by γ-aminopropyltriethoxysilane (KH550) and polydimethylsiloxane (PDMS) via wire rod coating. Due to the lower surface energy of PDMS and the hierarchical structure caused by the different aggregation sizes of TiO2 nanoparticles, the contact angle of the resulting superhydrophobic coating was 154.5° and the rolling angle was 3.5°. And the coated paper still had good non-wettability under water immersion. In addition, the coated paper was tolerant to mechanical damage and various temperature conditions. Even after 40 sandpaper wear cycles, the coating can still maintain good mechanical stability and superhydrophobicity. The superhydrophobic paper was used for oil-water separation, the separation efficiency was about 98% even after used 10 times. Furthermore, the prepared superhydrophobic paper exhibited excellent self-cleaning and anti-fouling properties, as well as demonstrated superb resistance to various water solutions owing to its high hydrophobicity. Moreover, the prepared superhydrophobic paper has application prospects in the industry of special wetting materials.     

Designing magnetic and superhydrophobic cellulose nanofibers based-aerogel for efficient oil water separation

In this work, we used cellulose nanofibers (CNF) as the skeleton, Fe₃O₄@ZnO composite particles as magnetic synergist particles, 3-(2-aminoethylamino) propyltrimethoxysilane (AS) and trimethoxy(octyl)silane (OTMS) as water-based hydrophobic modifiers to prepare magnetic and superhydrophobic cellulose nanofibers based-aerogel with low density and intricate three-dimensional structure. Fe₃O₄@ZnO confers magnetic properties (3.82 emu/g) and exceptional thermal stability (water contact angle of 150.1° at 200 °C) to the system, while the combination with OTMS/AS endows the system superhydrophobic (157.5°) and excellent mechanical properties (stress of 96.95 kPa at 80% strain). It is worth noting that in the process of modifying the system with OTMS/AS, no organic solvents and acidic substances are used in the solution. Benefiting from their synergies, the system demonstrates a notable oil absorption capacity (12.31–41.91 g/g) and outstanding oil selectivity (exceeding 90%), driven by gravity alone. Interestingly, this system, marked by its cost-effectiveness, simplicity, eco-friendliness, and heightened efficiency, holds promising prospects for diverse applications in different oil–water separation behavior and purifying industrial oil wastewater, as well as oil flooding incidents.     

pH值对硅油乳液Zeta电位及其制备的影响

1994年,T．M．Obey和V．Brian采用二甲基二乙氧基硅烷在氨水催化剂下进行乳液聚合,获得了具有较好单分散性的聚二甲硅油乳液。本文研究了pH值对二甲基二乙氧基硅乳液Zeta电位的影响,比较了有相同单体浓度的单相体系在低pH值(酸性)和高pH值(碱性)条件下乳液聚合的规律,以期对硅烷乳液制备做更进一步的研究。     

Superwetting and photocatalytic Ag2O/TiO2@CuC2O4 nanocomposite-coated mesh membranes for oil/water separation and soluble dye removal

A novel oily wastewater treatment strategy of simultaneously removing insoluble oily compounds and soluble organic pollutants is highly desirable. Herein, a hierarchical Ag₂O/TiO₂ heterojunction-loaded CuC₂O₄ nanosheet-decorated copper mesh (Ag₂O/TiO₂@CuC₂O₄ CM) was rationally designed by a combination of chemical etching and solvothermal deposition methods to implement the strategy. The Ag₂O/TiO₂@CuC₂O₄ CM with hierarchical nanostructures derived from hydrophilic CuC₂O₄ nanosheets and belt-like Ag₂O/TiO₂ heterojunction was proven to exhibit superior superhydrophilicity, underwater superoleophobicity, and photocatalytic ability, which greatly improved the antipollution ability of the substrate mesh. The as-fabricated mesh with a reasonable mesh number can efficiently separate oil/water mixtures with an ultra-high flux (～70 kL m^?2 h^?1) and surfactant-stabilized oil-in-water emulsions with an ultra-low residue oil content in filtrate (<60 mg L^?1). More importantly, the loaded heterojunction on the CM showed a high photodegradation efficiency of about 94.1% toward soluble methylene blue and self-cleaning ability to regenerate oil-contaminated mesh within 60 min under visible light irradiation by photo-Fenton-like reaction. Besides, the favorable salt resistance, acid and alkali resistance, and stability of the CM for long-term use were also observed. Thus, this study provides a new way for the treatment of complex oily wastewater.     

Continuous separation of oil from water surface by a novel tubular unit based on graphene coated polyurethane sponge

We develop a new strategy for the continuous separation of oil from water surface using a novel tubular unit based on graphene coated polyurethane (P‐GEPU) sponge, and the P‐GEPU sponge was fabricated by a simple dip‐coating method; the as‐prepared sponges could adsorb different kinds of oil and organic liquids while repelling water. Moreover, the tubular unit was assembled by wrapping the P‐GEPU sponge on a porous PU hollow tube and combined with the accessories including pipes and joints. The tubular unit could float on the surface of water, and a continuous oil collection from water surface through vacuum pressure could be fulfilled, showing a high oil‐water separation efficiency (>96%). Finally, oil‐water separation efficiency remains above 93% after 10 cycles, exhibiting excellent reusability. In addition, our findings are easily scaled up, showing a great promise for large‐scale oil spill remediation.     

Interfacial tension of alkylglucosides in different APG/oil/water systems

The interfacial performance of pure alkylglucosides (C₈G₁, C₁₀G₁ and C₁₂G₁) and of technical grade alkylpolyglucoside (APG) surfactants was investigated in three different water/oil systems (decane, isopropylmyristate and 2-octyldodecanol). From the dependence of the interfacial tension on the surfactant concentration below the CMC the cross-sectional area of the molecules at the decane/water interface was estimated. The plateau values of the interfacial tension at the CMC _c are independent of temperature and almost independent of added electrolyte in the decane/water system. The ability of the surfactants to lower the oil/water interfacial tension is most pronounced for the nonpolar oil. The partition coefficient of the surfactant between oil and water phase (k _c) was estimated from the CMC and the observed break point of the interfacial tension after equilibration of the two phases. In decane/water,k _c is nearly zero for all surfactants studied. For the polar oils,k _c increases with the chain length of the surfactant up tok _c10 for C₁₂G₁ in octyldodecanol/water. The values of _c in the different oil/water systems appear to be correlated withk _c and exhibit a minimum neark _c=1.     

Mechanically durable biomimetic fibrous membrane with superhydrophobicity and superoleophilicity for aqueous oil separation

Developing an effective and mechanically durable biomimetic membrane for the separation of highly emulsified aqueous oil is significant but challenging owing to its low water flux and serious membrane fouling. In this work, a biomimetic membrane with superhydrophobicity and superoleophilicity was rationally developed via co-electrospinning of polysulfonamide/polyacrylonitrile (PSA/PAN) emulsion solution, followed by decorating of α-Fe₂O₃ nanowire onto the membrane surface to create membrane roughness, and grafting of 1H,1H,2H,2H-perfluorododecyltrichlorosilane (FTCS) to lower membrane surface free energy. Benefiting from the nanowire-wrapped rough membrane structure and the low surface free energy FTCS, the resultant membrane showed superhydrophobicity with a high water contact angle (WCA) of 156°, superoleophilicity with a low oil contact angle (OCA) of 0°, which can separate the highly emulsified aqueous oil with an ultrahigh permeation flux over 7000 L m⁻² h^-1 and high separation efficiency of about 99%. Significantly, the biomimetic membrane also displayed robust stability for long-term separation owing to its advantage of antifouling property, showing great potential applications in large-scale aqueous oil treatment.     

Superhydrophobic polymer multilayers for the filtration- and absorption-based separation of oil/water mixtures

We report layer-by-layer approaches to the design of superhydrophobic and superoleophilic substrates for the filtration- or absorption-based separation of bulk oil from oil/water mixtures. Fabrication of covalently cross-linked, nanoporous polymer multilayers on mesh substrates yielded superhydrophobic and superoleophilic porous media that allow oil to pass, but completely prevent the passage of bulk water. This approach can be used to promote the filtration of oil/water mixtures, and these film-coated substrates can be bent and physically manipulated without affecting oil- and water-wetting properties. Fabrication on three-dimensional macroporous polymer pads yielded flexible objects that float on water and absorb oil at contaminated air/water interfaces. This approach permits oil to be recovered by squeezing or rinsing with solvent and the reuse of these materials without decreases in performance. These pads can also absorb oil from simulated seawater, brine, and other media representative of marine or industrial contexts where oil contamination can occur. Our results address issues associated with the design of polymer-based coatings for the separation, removal, and collection of oil from oil-contaminated water. With further development, this approach could provide low-energy alternatives to conventional remediation methods or yield new strategies that can be implemented in ways that are impractical using current technologies. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3127–3136