Dual-scaled porous nitrocellulose membranes with underwater superoleophobicity for highly efficient oil/water separation

Recent Advances in Nanoporous Membranes for Water Purification

Nanoporous materials exhibit wide applications in the fields of electrocatalysis, nanodevice fabrication, energy, and environmental science, as well as analytical science. In this review, we present a summary of recent studies on nanoporous membranes for water purification application. The types and fabrication strategies of various nanoporous membranes are first introduced, and then the fabricated nanoporous membranes for removing various water pollutants, such as salt, metallic ions, anions, nanoparticles, organic chemicals, and biological substrates, are demonstrated and discussed. This work will be valuable for readers to understand the design and fabrication of various nanoporous membranes, and their potential purification mechanisms towards different water pollutants. In addition, it will be helpful for developing new nanoporous materials for quick, economic, and high-performance water purification.

Cupric Phosphate Nanosheets-Wrapped Inorganic Membranes with Superhydrophilic and Outstanding Anticrude Oil-Fouling Property for Oil/Water Separation

Developing an effective and sustainable solution for cleaning up or separating oily water is highly desired. In this work, we report a completely inorganic mesh membrane made up of cupric phosphate (Cu₃(PO₄)₂) in a special intersected nanosheets-constructed structure. Combing the hierarchical structure with strong hydration ability of Cu₃(PO₄)₂, the nanosheets-wrapped membrane exhibits a superior superhydrophilic and underwater anti-oil-fouling and antibio-fouling property for efficient oil/water separation to various viscous oils such as heavy diesel oil, light crude oil, and even heavy crude oil with underwater oil contact angles (CAs) all above 158° and nearly zero underwater oil adhesive force even when a large preload force of up to 400 μN was applied on the oil droplet. Simultaneously, the membrane exhibits a high chemical and thermal stability and outstanding salt tolerance. Continuous separation operated on a cross-flow filtration apparatus demonstrates a large separation capacity and long-term stability of the membrane during treating a 2000 L crude oil/water mixture with constantly stable permeating flux of ∼4000 L/m² h and oil content in the filtrate below 2 ppm. The excellent anti-oil-fouling property, high separation capacity, and easily scaled-up preparation process of the membrane show great potential for practical application in treating oily wastewater.

An effective one-pot method for preparing covalently bonded nanocomposite soft magnetic beadlike microgels and their evaluation as an adsorbent for the removal of toxic heavy metals from aqueous solution

A simplified “water-in-oil” “one-pot” production process for preparing a covalently bonded nanocomposite soft magnetic beadlike adsorbent is developed.

Underwater superoleophobic polyurethane-coated mesh with excellent stability for oil/water separation

Oil/water separation has been a challenge in chemical engineering for various applications. There are numbers of studies on using coated metal meshes as a filter for oil/water separation. However, water resistance, chemical (such as: acid, base, and fouling) resistance and heat resistance for coating materials need further exploration, especially in terms of the durability of the coating materials. In this study, we synthesized a new coating material, hydrophilic polycarbonate polyurethane (HPCPU). We used HPCPU to chemically modify a steel mesh, and the mesh exhibits superhydrophilic and underwater superoleophobic properties. The HPCPU coated mesh shows excellent capacity for oil/water separation with a separation efficiency higher than 99.99% even after 40 cycles of separation. The coating material also exhibits excellent properties of water resistance, heat resistance, and chemical resistance. Moreover, the HPCPU-coated mesh exhibits a strong durability. For example, the separation efficiency for various oil/water mixtures remains higher than 99.7% after the HPCPU-coated mesh has been soaked in water for 30 days, hot water for 5 days, oils for 5 days, 0.5 M HCl solution, 0.5 M NaOH solution and 0.5 M NaCl solution for 24 hours.

Oil/water separation has been a challenge in chemical engineering for various applications.

Facile fabrication of zinc oxide coated superhydrophobic and superoleophilic meshes for efficient oil/water separation

Zinc oxide (ZnO) coated superhydrophobic and superoleophilic stainless steel meshes are facilely fabricated via chemical immersion growth and subsequent surface modification. The as-prepared meshes show good mechanical durability, chemical stability and corrosion-resistant properties due to a combination of the hierarchical ZnO structure and the low surface energy modification. More importantly, the as-prepared meshes are used for highly efficient separation of various oil/water mixtures. Meanwhile, a new oil skimmer based on the as-prepared mesh is proposed to spontaneously collect floating oil with high separation efficiency and desirable durability.

Zinc oxide coated superhydrophobic and superoleophilic stainless steel mesh was fabricated by a simple and inexpensive approach for efficient oil/water separation.

A glucose modified filter paper for effective oil/water separation

Toluene/water emulsion cannot be separated by the un-treated filter paper. In comparison, toluene/water emulsion could be efficiently separated by the glucose (GLC) treated filter paper.

Synthesis of thorium–ethanolamine nanocomposite by the co-precipitation method and its application for Cr(vi) removal

Studies on the adsorption of Cr(vi) from water by a thorium ethanolamine nanocomposite.

Selective Cooperation with Liquids for Environmentally Friendly and Comprehensive Oil-Water Separation

A hydrophobic 3 D material having smart relationship with oil under water (having both water affinity and water repellency in absence and presence of oil), is developed here using a scalable and facile 1,4-conjugate addition reaction between acrylate and amine groups at ambient conditions without using any catalyst. The material that was soaked with water in air is capable of absorbing both heavy and light oils with an efficiency above 1000 wt %, and the impregnated metastable aqueous phase was spontaneously and selectively ejected out from the material. This unprecedented super-oil-absorbance property remained intact in diverse scenarios, including extremes of temperature (100 and 10 °C), pressure (184.7 mbar), and prolonged (7 days) exposures to extremes of pH (1 and 12), surfactants-contaminated (dodecyltrimethylammonium bromide/sodium dodecyl sulfate, DTAB/SDS, 1 mm) water, artificial sea water, etc. Furthermore, this super-oil-absorbent having outstanding durability was exploited also in demonstrations of comprehensive and facile clean-up of oil from various forms of oil-water mixtures (i.e., floating light-oil, sediment heavy-oil, oil-in-water emulsions, etc.) in extremes and complex settings that are relevant to practical scenarios including marine oil spills, following ecofriendly and energy-efficient selective-absorption/active-filtration principles.

Controlling Superwettability by Microstructure and Surface Energy Manipulation on Three-Dimensional Substrates for Versatile Gravity-Driven Oil/Water Separation

Superwettable materials have gained tremendous attention because of their special wetting abilities. The key to obtaining and tuning superwettability is to precisely control the interfacial microstructures and surface energies of materials. Herein, we propose a novel approach to controlling the superwettability of three-dimensional foams. The surface microstructure was manipulated by the layer-by-layer covalent grafting of multidimensional nanoparticles (e.g., silica, carbon nanotubes, and graphene oxide), and the surface energy was tailored by grafting chemicals with different functional groups. This grafting approach improved the mechanical performance, reduced particle loading, and prevented particle disassociation, thereby increasing the absorption capacity and durability of the functionalized foams. More importantly, superhydrophobic/superoleophilic foams were obtained after heptanol grafting. They showed water contact angles of 153° in air and 158° in oil, an absorption capacity 113 times their weight gain, and a remarkable flux of 32.6 L m^-2 s^-1 for the separation of oil from water driven by gravity. Polydopamine grafting resulted in superhydrophilic/underwater superoleophobic foams that had an oil contact angle of 152° under water and a high flux of 19.3 L m^-2 s^-1 for the separation of water from oil. Thus, this study offers not only intelligent materials for versatile oil/water separation but also a profound approach for engineering high-performance superwettable materials.

A Janus oil barrel with tapered microhole arrays for spontaneous high-flux spilled oil absorption and storage

Porous oil/water separation materials show excellent prospects in the remediation of oil spill accidents. However, several drawbacks such as low flux, limited absorption and storage capacity restrict their practical applications. Hence, a novel Janus oil barrel (superhydrophobic outside wall and superhydrophilic inside wall) constituted by tapered microhole arrayed aluminium foil is designed, which is demonstrated to be a promising device for the remediation of oil spill accidents. Furthermore, the investigation shows that the tapered microholes (taper angle 25-30°) can significantly enhance oil/water intrusion pressures (1-3 times higher than cylindrical holes) and unidirectional transferability which can eliminate the secondary leakage when salvaging full oil barrels without an additional procedure. It is indicated that the Janus oil barrel can spontaneously absorb spilled oil with a high flux (45 000 Lm^-2 h^-1), and synchronously store the absorbed oil. In addition, the barrel can absorb oil from surfactant-free oil-in-water emulsions appearing in oil spills and industrial processes. The distinct design combining excellent controllability, high precision and flexibility of the femtosecond laser micro/nanofabrication technology provides a general strategy in oil spill remediation.

Under-oil superhydrophilic wetted PVDF electrospun modified membrane for continuous gravitational oil/water separation with outstanding flux

Water in the world is becoming an increasingly scarce commodity and the membrane technology is a most effective strategy to address this issue. However, the fouling and low flux of the polymeric membrane remains the big challenges. Novel modified Polyvinylidene fluoride (PVDF) membrane was introduced, in this work, using a novel treatment technique for an electrospun polymeric PVDF membrane to be used in oil/water separation systems. The Characterizations of the modified and pristine membranes showed distinct changes in the phase and crystal structure of the membrane material as well as the wettability. The modification process altered the surface morphology and structure of the membrane by forming hydrophilic microspheres on the membrane surface. Therefore, the proposed treatment converts the membrane from highly hydrophobic to be a superhydrophilic under-oil when wetted with water. Accordingly, in the separation of oil/water mixtures, the modified membrane can achieve an outstanding flux of 20664 L/m². hr under gravity, which is higher than the pristine membrane by infinite times. Moreover, in the separation of the emulsion, a high flux of 2727 L/m². h was achieved. The results exhibited that the modified membrane can treat a huge amount of oily water with a minimal energy consumption. The corresponding separation efficiencies of both of oil/water mixtures and emulsion are more than 99%. The achieved characteristics for the modified and pristine membranes could be exploited to design a novel continuous system for oil/water separation with an excellent efficiency.

Closed Pore Structured NiCo2O4-Coated Nickel Foams for Stable and Effective Oil/Water Separation

To solve the serious problem caused by oily wastewater pollution, unique interface designs, for example, membranes with superwetting properties such as superhydrophobicity/superoleophilicity and superhydrophilicity/underwater superoleophobicity, provide a good way to achieve oil/water separation. Here, inspired by the liquid storage property of the honeycomb structure, we propose a strategy to fabricate NiCo₂O₄-coated nickel foams for stable and efficient oil/water separation. NiCo₂O₄ with a closed-pore structure was formed by assembling nanoflakes with a micro/nanoscale hierarchical structure. Compared with nickel foam coated by NiCo₂O₄ with an open-pore structure (NiCo₂O₄ nanowires), the enclosed nanostructure of NiCo₂O₄ nanoflakes can firmly hold water for a more stable superhydrophilic/underwater superoleophobic interface. As a consequence, the NiCo₂O₄-nanoflake-coated nickel foam has a larger oil breakthrough pressure than the NiCo₂O₄-nanowire-coated nickel foam because of a slightly larger oil advancing angle and a lower underwater oil adhesion force, which makes it more stable and efficient for oil/water separation. Moreover, the NiCo₂O₄-coated nickel foams have excellent chemical and mechanical stability, and they are reusable for oil-water separation. This work will be beneficial for the design and development of stable underwater superoleophobic self-cleaning materials and related device applications, such as oil/water separation.

Preparation of Superhydrophilic and Underwater Superoleophobic Nanofiber-Based Meshes from Waste Glass for Multifunctional Oil/Water Separation

The deterioration of water resources due to oil pollution, arising from oil spills, industrial oily wastewater discharge, etc., urgently requires the development of novel functional materials for highly efficient water remediation. Recently, superhydrophilic and underwater superoleophobic materials have drawn significant attention due to their low oil adhesion and selective oil/water separation. However, it is still a challenge to prepare low-cost, environmentally friendly, and multifunctional materials with superhydrophilicity and underwater superoleophobicity, which can be stably used for oil/water separation under harsh working conditions. Here, the preparation of nanofiber-based meshes derived from waste glass through a green and sustainable route is demonstrated. The resulting meshes exhibit excellent performance in the selective separation of a wide range of oil/water mixtures. Importantly, these meshes can also maintain the superwetting property and high oil/water separation efficiency under various harsh conditions. Furthermore, the as-prepared mesh can remove water-soluble contaminants simultaneously during the oil/water separation process, leading to multifunctional water purification. The low-cost and environmentally friendly fabrication, harsh-environment resistance, and multifunctional characteristics make these nanofiber-based meshes promising toward oil/water separation under practical conditions.

A robust salt-tolerant superoleophobic alginate/graphene oxide aerogel for efficient oil/water separation in marine environments

Marine pollution caused by frequent oil spill accidents has brought about tremendous damages to marine ecological environment. Therefore, the facile large-scale preparation of three-dimensional (3D) porous functional materials with special wettability is in urgent demand. In this study, we report a low-cost and salt-tolerant superoleophobic aerogel for efficient oil/seawater separation. The aerogel is prepared through incorporating graphene oxide (GO) into alginate (ALG) matrix by using a facile combined freeze-drying and ionic cross-linking method. The 3D structure interconnected by ALG and GO ensures the high mechanical strength and good flexibility of the developed aerogel. The rough microstructure combined with the hydrophilicity of the aerogel ensures its excellent underwater superoleophobic and antifouling properties. High-content polysaccharides contained in the aerogel guarantees its excellent salt-tolerant property. More impressively, the developed aerogel can retain its underwater superoleophobicity even after 30 days of immersion in seawater, indicating its good stability in marine environments. Furthermore, the aerogel could separate various oil/water mixtures with high separation efficiency (>99%) and good reusability (at least 40 cycles). The facile fabrication process combined with the excellent separation performance makes it promising for practical applications in marine environments.

Chemical and Equipment-Free Strategy To Fabricate Water/Oil Separating Materials for Emergent Oil Spill Accidents

Oil spill accidents normally have two important features when considering practical cleanup strategies: (1) unexpected occurrence in any situations possibly without specific equipment and chemicals; (2) emergency to be cleaned to minimize the influences on ecosystems. To address these two practical problems regarding removal of spilt oil, we have proposed an in situ, rapid, and facile candle-soot strategy to fabricate water/oil separating materials based on superhydrophobicity/superoleophilicity. The one-step fabrication method is independent of any chemicals or equipment and can be ready for use through short smoking processes within 5 min by using raw materials available in daily life such as textiles. The as-prepared materials perform good durability for repeated separation test and high recovery rate of various oils from water/oil mixtures. This strategy provides possibility of rapid response to sudden oil spill accidents, especially in cases without any equipment or chemicals and in poor countries/areas those could hardly afford transportation and storage of expensive separating materials.

Oxidant-Induced High-Efficient Mussel-Inspired Modification on PVDF Membrane with Superhydrophilicity and Underwater Superoleophobicity Characteristics for Oil/Water Separation

In this work, a facile one-step approach was developed to modify hydrophobic polyvinylidene fluoride (PVDF) microfiltration membrane with superhydrophilicity and underwater superoleophobicity properties via a high-efficient deposition of polydopamine (PDA) coating oxidized by sodium periodate in a slightly acidic environment (pH = 5.0). In contrast to the traditional PDA coating on hydrophobic membranes autoxidized by O₂ in a weak basic buffer solution, the superhydrophilicity and ultrahigh pure water permeability (about 11 934 L m^-2 h^-1 under 0.038 MPa) of the PDA-decorated PVDF membrane are derived from optimized chemical oxidation without postmodifications or additional reactants. The as-prepared membrane exhibits excellent oil/water separation ability evaluated by water fluxes and oil rejection ratios of various oil/water mixtures and oil-in-water emulsions. Moreover, the outstanding antifouling performance and reusability of the PDA-modified PVDF membrane provide a long-term durability for many potential applications. The modified membrane also exhibits excellent chemical stability in harsh pH environments and mechanical stability for practical applications.

Facile Selective and Diverse Fabrication of Superhydrophobic, Superoleophobic-Superhydrophilic and Superamphiphobic Materials from Kaolin

As the starting material, kaolin is selectively and diversely fabricated to the superhydrophobic, superoleophobic-superhydrophilic, and superamphiphobic materials, respectively. The wettability of the kaolin surface can be selectively controlled and regulated to different superwetting states by choosing the corresponding modification reagent. The procedure is facile to operate, and no special technique or equipment is required. In addition, the procedure is cost-effective and time-saving and the obtained super-repellent properties are very stable. The X-ray photoelectron spectroscopy analysis demonstrates different changes of kaolin particles surfaces which are responsible for the different super-repellency. The scanning electron microscopy displays geometric micro- and nanometer structures of the obtained three kinds of super-repellent materials. The results show that kaolin has good applications in many kinds of superwetting materials. The method demonstrated in this paper provides a new strategy for regulating and controlling the wettability of solid surfaces selectively, diversely, and comprehensively.

Superoleophobic surfaces

This review systematically summarizes the recent developments of superoleophobic surfaces, focusing on their design, fabrication, characteristics, functions, and important applications.

Super-stable non-woven fabric-based membrane as a high-efficiency oil/water separator in full pH range

A polystyrene coated non-woven fabric hybrid membrane with superoleophilicity has been synthesized by a facile polymerization reaction for high-efficiency separation of oils in harsh environments.

A robust duplex Cu/PDMS-coated mesh with superhydrophobic surface for applications in cleaning of spilled oil

In this study, we created a robust nanostructure coated on the surface of a mesh via the electrodeposition and chemical modification to enhance the mechanical durability of the mesh surface with superhydrophobic performance.

An anti-fouling poly(vinylidene fluoride) hybrid membrane blended with functionalized ZrO2 nanoparticles for efficient oil/water separation

Functionalized nanoparticle of ZrO₂ grafted with poly(N-acryloylmorpholine) was synthesized via radical grafting polymerization. The nanoparticle was directly blended with PVDF to prepare hybrid membrane. The efficient separation of oil/water mixture is established.

Robust Underwater Oil-Repellent Material Inspired by Columnar Nacre

Inspired by natural columnar nacre, artificial montmorillonite/hydroxyethyl cellulose columnar nacre-like materials with a site-specific layered structure in the interior and a hierarchical columnar structure on the surface are prepared. The materials exhibit improved tensile strength, good chemical stability in seawater, superior resistance to sand-grain impingement, and robust underwater low-adhesive superoleophobicity.

Fabrication of Silica Nanospheres Coated Membranes: towards the Effective Separation of Oil-in-Water Emulsion in Extremely Acidic and Concentrated Salty Environments

A superhydrophilic and underwater superoleophobic surface is fabricated by simply coating silica nanospheres onto a glass fiber membrane through a sol-gel process. Such membrane has a complex framework with micro and nano structures covering and presents a high efficiency (more than 98%) of oil-in-water emulsion separation under harsh environments including strong acidic and concentrated salty conditions. This membrane also possesses outstanding stability since no obvious decline in efficiency is observed after different kinds of oil-in-water emulsions separation, which provides it candidate for comprehensive applicability.

Polyacrylamide-Polydivinylbenzene Decorated Membrane for Sundry Ionic Stabilized Emulsions Separation via a Facile Solvothermal Method

Aiming to solve the worldwide challenge of stabilized oil-in-water emulsion separation, a PAM-PDVB decorated nylon membrane is fabricated via a facile solvothermal route in our group. The main composition is PAM, while the PDVB plays a role as cross-linker in order to improve the interaction between the polymer and the substrate. By the combination of the superhydrophilic and underwater superoleophobic wettability of the PAM polymer with the micropore size of the substrate, the as-prepared material is able to achieve the separation of various stabilized oil-in-water emulsions including cationic type, nonionic type, and anionic type. Compared with previous works, the emulsions used in this case are more stable and can stay for several days. Besides, the solvothermal method is facile, cost saving, and relatively environmentally friendly in this experiment. Moreover, the PAM-PDVB modified membrane exhibits excellent pH stability, recyclability, and high separation efficiency (above 99%), which can be scaled up and used in the practical industrial field.

A Robust Polyionized Hydrogel with an Unprecedented Underwater Anti-Crude-Oil-Adhesion Property

A polyionized hydrogel polymer (sodium polyacrylate-grafted poly(vinylidene fluoride) (PAAS-g-PVDF)) is fabricated via an alkaline-induced phase-inversion process. PAAS-g-PVDF coatings exhibit unprecedented anti-adhesion and self-cleaning properties to crude oils under an aqueous environment. A PAAS-g-PVDF-coated copper mesh can effectively separate a crude oil/water mixture with extremely high flux and high oil rejection driven by gravity, and is oil-fouling-free for long-term use.

A biologically inspired attachable, self-standing nanofibrous membrane for versatile use in oil-water separation

Uloborus walckenaerius spider webs provided the inspiration for attachable, self-standing nanofibre sheets. The developed product adds selective wettability against oil-water mixtures to both 2D and 3D materials by attaching or covering them, leading to successful separation through a facile, scalable and low-cost process.

Thermal Processing of Silicones for Green, Scalable, and Healable Superhydrophobic Coatings

The thermal degradation of silicones is exploited and engineered to make super-hydrophobic coatings that are scalable, healable, and ecofriendly for various outdoor applications. The coatings can be generated and regenerated at the rate of 1 m(2) min(-1) using premixed flames, adhere to a variety of substrates, and tolerate foot traffic (>1000 steps) after moderate wear and healing.

Recent Development of Advanced Materials with Special Wettability for Selective Oil/Water Separation

The increasing number of oil spill accidents have a catastrophic impact on our aquatic environment. Recently, special wettable materials used for the oil/water separation have received significant research attention. Due to their opposing affinities towards water and oil, i.e., hydrophobic and oleophilic, or hydrophilic and oleophobic, such materials can be used to remove only one phase from the oil/water mixture, and simultaneously repel the other phase, thus achieving selective oil/water separation. Moreover, the synergistic effect between the surface chemistry and surface architecture can further promote the superwetting behavior, resulting in the improved separation efficiency. Here, recently developed materials with special wettability for selective oil/water separation are summarized and discussed. These materials can be categorized based on their oil/water separating mechanisms, i.e., filtration and absorption. In each section, representative studies will be highlighted, with emphasis on the materials wetting properties and innovative aspects. Finally, challenges and future research directions in this emerging and promising research field will be briefly described.

Fluorine-Free Superhydrophobic Coatings with pH-induced Wettability Transition for Controllable Oil-Water Separation

We present a simple, environmentally friendly approach to fabricating superhydrophobic coatings with pH-induced wettability transition. The coatings are prepared from a mixture of silica nanoparticles and decanoic acid-modified TiO2. When the coating is applied on cotton fabric, the fabric turns superhydrophobic in air but superoleophilic in neutral aqueous environment. It is permeable to oil fluids but impermeable to water. However, when the coated fabric is placed in basic aqueous solution or ammonia vapor, it turns hydrophilic but underwater superoleophobic, thus allowing water to penetrate through but blocking oil. Therefore, such a unique, selective water/oil permeation feature makes the treated fabric have capability to separate either oil or water from a water-oil mixture. It may be useful for development of smart oil-water separators, microfluidic valves, and lab-on-a-chip devices.

Environmental Applications of Interfacial Materials with Special Wettability

Interfacial materials with special wettability have become a burgeoning research area in materials science in the past decade. The unique surface properties of materials and interfaces generated by biomimetic approaches can be leveraged to develop effective solutions to challenging environmental problems. This critical review presents the concept, mechanisms, and fabrication techniques of interfacial materials with special wettability, and assesses the environmental applications of these materials for oil-water separation, membrane-based water purification and desalination, biofouling control, high performance vapor condensation, and atmospheric water collection. We also highlight the most promising properties of interfacial materials with special wettability that enable innovative environmental applications and discuss the practical challenges for large-scale implementation of these novel materials.

Free-Standing Graphene Oxide-Palygorskite Nanohybrid Membrane for Oil/Water Separation

Graphene oxide (GO) is an emerging kind of building block for advanced membranes with tunable passageway for water molecules. To synergistically manipulate the channel and surface structures/properties of GO-based membranes, the different building blocks are combined and the specific interfacial interactions are designed in this study. With vacuum-assisted filtration self-assembly, palygorskite nanorods are intercalated into adjacent GO nanosheets, and GO nanosheets are assembled into laminate structures through π-π stacking and cation cross-linking. The palygorskite nanorods in the free-standing GOP nanohybrid membranes take a 3-fold role, rendering enlarged mass transfer channels, elevating hydration capacity, and creating hierarchical nanostructures of membrane surfaces. Accordingly, the permeate fluxes from 267 L/(m(2) h) for GO membrane to 1867 L/(m(2) h) for GOP membrane. The hydration capacity and hierarchical nanostructures synergistically endow GOP membranes with underwater superoleophobic and low oil-adhesive water/membrane interfaces. Moreover, by rationally imparting chemical and physical joint defense mechanisms, the GOP membranes exhibit outstanding separation performance and antifouling properties for various oil-in-water emulsion systems (with different concentration, pH, or oil species). The high water permeability, high separation efficiency, as well as superior anti-oil-fouling properties of GOP membranes enlighten the great prospects of graphene-based nanostructured materials in water purification and wastewater treatment.

Microscopic Dimensions Engineering: Stepwise Manipulation of the Surface Wettability on 3D Substrates for Oil/Water Separation

Microscopic dimensions engineering is proposed to devise a series of 3D superhydrophobic substrates with microstructures of different dimensions. Combined theoretical modeling and experiments give the relationship of surface roughness and superhydrophobic properties, important for guiding the design of superior superwettable materials for water remediation and other uses.

Ultrathermostable, Magnetic-Driven, and Superhydrophobic Quartz Fibers for Water Remediation

A quartz fiber based 3D monolithic materials was fabricated, which combines ultrahigh thermostability, remote controllability, mechanical flexibility, high water/oil selectivity, high processing capacity, and regeneration ability. This material exhibited great potential in water remediation, such as large absorption capacity (50- to 172-fold weight gain) toward oil standing in front of all magnetic sorbents and remarkable oil/water separation performance.

Oil removal from water–oil emulsions using magnetic nanocomposite fibrous mats

PMMA-based magnetic nanocomposite fibrous mats reach oil absorption efficiencies up to 90% in water–oil stable emulsions.

A facile method of synthesizing size-controlled hollow cyanoacrylate nanoparticles for transparent superhydrophobic/oleophobic surfaces

A novel method to synthesize size-controllable hollow polymeric nanoparticles is reported. The synthesis process completes in a moment with tunable particle diameters. Coated surfaces show superhydrophobicity/oleophobicity with high transparency.

A robust salt-tolerant superoleophobic aerogel inspired by seaweed for efficient oil–water separation in marine environments

A robust salt-tolerant superoleophobic aerogel was fabricated by a simple combined freeze-drying and ionic cross-linking method for oil–seawater separation.

Multifunctional Hybrid Porous Micro-/Nanocomposite Materials

Multifunctional hybrid porous micro-/nanocomposite materials with hierarchical structures of soft silicone nanofilaments on hard porous glass microbeads are designed and synthesized. Such materials display selective super-antiwetting/superwetting properties with unique mechanical, chemical, and thermal stabilities, as well as excellent antifouling properties. They are ideal materials for highly efficient separation of oil/water mixtures and emulsions, and display great advantages as carriers for organocatalysts.