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Due to ever‐increasing environmental problems caused by oily wastewater, it is necessary to develop methods for separating oil/water mixtures. However, oil‐in‐water and water‐in‐oil emulsions are highly stable due to the action of surfactants, making them enormously difficult to separate. In this study, we report a 3D superhydrophobic/superoleophilic porous material with a microporous structure and strong negative charge via high internal phase emulsion polymerization to overcome these difficulties. The introduction of 10 wt% α‐zirconium phosphate significantly improved the hydrophobicity of the material (water contact angle = 153°) and also endowed the material with a strong negative charge. The material could separate immiscible oil/water mixtures under turbulent condition and high‐ or low‐temperature environments. Driven by gravity, the as‐prepared monolith separated various oil/water mixtures with the separation efficiency exceeding 99.16%. Benefiting from the diametrically‐opposing wettability and interconnected micropore structure, the foam could separate a Span 80‐stabilized water‐in‐oil emulsion. Furthermore, a cationic surfactant‐stabilized oil‐in‐water emulsion was also separated due to strong electrostatic interactions, which destabilized the oil/water interfacial film. Based on these properties, the as‐prepared porous material shows huge potential for complex oily wastewater treatment. [ABSTRACT FROM AUTHOR]

The superhydrophilic/underwater superoleophobic 3D porous material was fabricated by chemical/physical cross-linking of cellulose nanofibers (CNF) and polyethyleneimine (PEI). This material had excellent antifouling performance, which could long-lasting separate oil-in-water emulsion and adsorb water-soluble organic dyes. [Display omitted] • A dual-functional porous material with excellent antifouling performance is prepared. • The material exhibits underwater structural stability and chemical/thermal durability. • Dyes are adsorbed by electrostatic action, hydrogen bonding, physical adsorption. • The material can efficiently separate O/W emulsion and organic dyes in one step. • The removal efficiencies for O/W emulsion and organic dyes are higher than 99.5%. There is an urgent demand for 3D porous materials with dual-functionality for simultaneous separation of highly stable oil/water emulsion and water-soluble organic dyes from complex industrial wastewaters, but still remains a challenge. Herein, a superhydrophilic/underwater superoleophobic material with excellent antifouling ability was fabricated by chemical/physical cross-linking of cellulose nanofibers (CNF) with polyethylenimine (PEI) for enduringly effective separation of oil-in-water emulsion and adsorption of organic dyes. The multiple chemical/physical crosslinks between CNF and PEI endowed the CNF-g-PEI 2 with excellent underwater structural stability and chemical/thermal durability. The superhydrophilic composition (–OH, –NH, –NH 2), derived from CNF and PEI, showed high hydration capacity. It provided the material with excellent antifouling performance and underwater oil release ability. The separation efficiency and separation flux of CNF-g-PEI 2 for five oil-in-water emulsions (chloroform-in-water, toluene-in-water, petroleum ether-in-water, diesel oil-in-water, and soybean oil-in-water) were higher than 99.54 % and 2188.4 L·h−1·m−2, respectively. More importantly, the CNF-g-PEI 2 could continuously separate 1000 mL of emulsion with a separation efficiency of more than 97.06 % and separation flux of above 1889.75 L·h−1·m−2. Furthermore, the porous CNF-g-PEI 2 material could adsorb and separate anionic/cationic dyes through electrostatic actions, hydrogen bonding, and physical adsorption, exhibiting very high adsorption capacity (≥215.0 mg/g) and the rejection (≥99.5 %). These outstanding properties make CNF-g-PEI 2 porous material a promising candidate for separation of oil-in-water emulsion and removal of water-soluble organic dyes. [ABSTRACT FROM AUTHOR]

Three-dimensional superhydrophobic/superlipophilic porous materials have attracted widespread attention for use in the separation of oil/water mixtures. However, a simple strategy to prepare superhydrophobic porous materials capable of efficient and continuous separation of immiscible and emulsified oil/water mixtures has not yet been realized. Herein, a superhydrophobic graphene/polystyrene composite material with a micro-nanopore structure was prepared by a single-step reaction through high internal phase emulsion polymerization. Graphene was introduced into the polystyrene-based porous materials to not only enhance the flexibility of the matrix, but also increase the overall hydrophobicity of the composite materials. The resulting as-prepared monoliths had excellent mechanical properties, were superhydrophobic/superoleophilic (water/oil contact angles were 151° and 0°, respectively), and could be used to continuously separate immiscible oil/water mixtures with a separation efficiency that exceeded 99.6%. Due to the size-dependent filtration and the tortuous and lengthy micro-nano permeation paths, our foams were also able to separate surfactant-stabilized water-in-oil microemulsions. This work demonstrates a facile strategy for preparing superhydrophobic foams for the efficient and continuous separation of immiscible and emulsified oil/water mixtures, and the resulting materials have highly promising application potentials in large-scale oily wastewater treatment. [ABSTRACT FROM AUTHOR]

Superhydrophobic polymeric foams, with good thermal stability and high‐recycling capacity to remove oil from oily wastewater, are highly desirable for current oily wastewater purification. Herein, poly (styrene‐acrylic acid 2,2,3,4,4,4‐hexafluoro‐butyl ester‐divinylbenzene) foam with porosity as high as 99.27% has been prepared through high‐internal phase emulsions. Therein, poly (cyclotriphosphazene‐co‐4,4′‐sulfonyldiphenol) microspheres, and Span80 act as co‐emulsifier to stabilize the emulsion system. The as‐prepared foams exhibited super hydrophobicity with a water contact angle of 150.3° and thermal stability. Additionally, the oil adsorption capacity of the porous material could reach up to 25.6–53.4 times its mass with accessible and high‐recycling capacity. These aforementioned outstanding properties make our superhydrophobic foam hold potential applications in oil/water separation. [ABSTRACT FROM AUTHOR]

The P(St-DVB-TMPTA)/PEI 20 porous material with underliquid dual superlyophobicity prepared by high internal phase emulsion polymerization one-pot method which can efficiently separate surfactant stabilized oil–water emulsion and adsorb Cu2+ in water. This study would provide a new approach to prepare an underliquid dual superlyophobicity porous material with multifunctional for the treatment of complex oily wastewater. [Display omitted] • 3D material with underliquid dual superlyophobic is constructed via one-pot method. • The underliquid dual superlyophobicity is designed by hydrophilic-hydrophobic chain. • The porous material can efficiently separate various stable O/W and W/O emulsions. • The material can also adsorb Cu2+ in water through metal ion chelation coordination. Multifunctional materials for the simultaneous separation of oil-in-water or water-in-oil emulsions and adsorption of heavy metal ions are urgently needed for treating industrial wastewater with complex composition; however, at present these materials are strictly limited to a single function. To meet the above demand, a 3D polystyrene–divinylbenzene–trimethylolpropane triacrylate/polyethyleneimine (P(St-D-T)/PEI 20) porous material with underliquid dual superlyophobicity was designed and prepared by the high internal phase emulsion polymerization one-pot method. Based on a structural design strategy involving the combination of hydrophilic and hydrophobic segments, hydrophilic and cationic PEI components were chemically grafted onto the surface of the hydrophobic P(St-D-T) porous material through a 1,4-conjugate addition reaction, endowing the material with underliquid dual superlyophobicity and metal ion-chelating coordination groups. The as-prepared material could continuously separate surfactant-stabilized oil-in-water and water-in-oil emulsions, with corresponding separation efficiencies of 99.4 % and 97.4 %, along with separation fluxes of 2543 and 8363 L m-2h−1 bar−1, respectively. The material also possessed excellent mechanical stability and outstanding chemical corrosion resistance. Furthermore, the P(St-D-T)/PEI 20 porous material could adsorb Cu2+ in water through metal ion chelation, with a maximum adsorption capacity of 190.2 mg/g. This study provides a new approach to prepare a porous material with underliquid dual superlyophobicity for the treatment of complex oily wastewater. [ABSTRACT FROM AUTHOR]

Three-dimensional separation materials with robust physical/chemical stability have great demand for effective and continuous separation of immiscible oil/water mixtures and water-in-oil emulsions, resulting from chemical leakages and discharge of industrial oily wastewaters. Herein, a superelastic polystyrene-based porous material with superhydrophobicity/superoleophilicity was designed and prepared by high internal phase emulsion polymerization to meet the aforementioned requirements. A flexible and hydrophobic aminopropyl terminated polydimethylsiloxane (NH 2 -PDMS-NH 2) segment was introduced into the rigid styrene-divinylbenzene copolymer through 1, 4-conjugate addition reaction with trimethylolpropane triacrylate. The addition of NH 2 -PDMS-NH 2 simultaneously improved the mechanical and hydrophobic properties of the porous material (the water contact angle from 141.2° to 152.2°). The material exhibited outstanding reversible compressibility (80% strain, even in liquid N 2 environments) and superhydrophobic stability, even after being repeatedly compressed 100 times, water contact angle still remained above 150°. Meanwhile, the as-prepared material had outstanding hydrophobic stability in corrosive solutions (strong acidic, alkaline, high-salty, and even strong polar solvent), presence of mechanical interference, strong UV radiations, and high/low temperature environments. More importantly, the material could continuously and efficiently separate immiscible oil/water mixture and water-in-oil emulsions under the above conditions, showing huge potential for the large-scale remediation of complex oily wastewaters. [Display omitted] • Porous elastomers were fabricated by crosslinking "soft and hard" segments in HIPE. • The material had improved superelastic and hydrophobic compared to other polyHIPEs. • The porous material held excellent superhydrophobic stability in harsh conditions. • Multiple oil/water mixtures and highly stable emulsion could be efficiently separated. [ABSTRACT FROM AUTHOR]