Facile Fabrication of Superhydrophobic Graphene/Polystyrene Foams for Efficient and Continuous Separation of Immiscible and Emulsified Oil/Water Mixtures

Abstract

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.

A robust superhydrophobic and superoleophilic SA-HKUST-1 membrane for efficient oil/water mixture separation

“…These discharges require secondary treatment, which increases costs and is poorly adapted; in addition, different separation methods have specific requirements for the physical and chemical properties of oil-water mixtures, such as the need for a large density difference between oil and water, which is necessary to achieve effective separation, which limits the scope of these methods. 17 In recent years, inspired by bionics [18][19][20] researchers have discovered that some super wettable materials with surface micro-nano rough structures are making a splash in the field of oil-water separation, such as fabrics, 21,22 meshes, [23][24][25] foams, [26][27][28] sponges, 29,30 gels [31][32][33] and Janus smart materials based on the above materials. 34 These materials have been modified to achieve a significant increase in separation efficiency and to have emerging applications such as self-cleaning 35 and photocatalytic degradation of pollutants.…”

“…In recent years, inspired by bionics 18–20 researchers have discovered that some super wettable materials with surface micro–nano rough structures are making a splash in the field of oil–water separation, such as fabrics, 21,22 meshes, 23–25 foams, 26–28 sponges, 29,30 gels 31–33 and Janus smart materials based on the above materials. 34 These materials have been modified to achieve a significant increase in separation efficiency and to have emerging applications such as self-cleaning 35 and photocatalytic degradation of pollutants.…”