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Recently, the membrane separation materials show promising applications in the fields of crude oil removal because of their low energy consumption and less secondary pollution. However, the membrane separation materials suffer problem of low separation efficiency due to the high viscosity of crude oil. Here, a superhydrophobic material with Joule heat and photothermal effect was prepared by decorating the delignified wood with reduced graphene oxide (GSH) and vinyl terminated polydimethylsiloxane (V-PDMS) through thiol-ene click reaction. The prepared PDMS@GSH wood exhibited stable superhydrophobicity with a water contact angle of 156°. Meanwhile, the GSH layer provided promising electrothermal effect that endowed the PDMS@GSH wood with excellent crude oil/water separation capability under the Joule heat with a surface temperature of 139 °C and separation rate of 1.78 × 105 kg m−3 h−1. Besides, the PDMS@GSH wood displayed a good photothermal effect that assisted with the Joule heat to heat the wood for crude oil removal to save energy. More importantly, the PDMS was crosslinked with GSH on the wood via thiol-ene click reaction, leading to the stable superhydrophobicity and electrical conductivity in strong acid or alkali environment. This material has broad application prospects in crude oil clean-up due to its high separation speed and easy large-scale production. [Display omitted] • A new strategy for fabricating superhydrophobic wood with heating property is proposed. • The wood presents stable superhydrophobicity and electrical conductivity. • The wood shows excellent Joule heat and photothermal effect. • The wood exhibits high separation rate for viscous crude oil wastewater. [ABSTRACT FROM AUTHOR]

Functional membranes with electrothermal/photothermal effects are considered an effective method for separating water/viscous crude oil mixtures. However, the loading of photothermal and electrothermal particles in polymeric membranes with poor compatibility will deteriorate the membrane performance, leading to the unstable photothermal/electrothermal effects. Therefore, we prepared a hydrophobic sandwich structure polyvinylidene fluoride/reduced graphene oxide/polydimethylsiloxane (PVDF/rGO/PDMS) composite membrane using a two-step electrospinning process, which improved the binding force between the photothermal/electrothermal particles and the matrix with the composite membrane exhibiting super fast electric heating and photothermal effect. The temperature of the composite membrane surface rapidly reached to 162.5 °C within 30 s at 25 V. In addition, the addition of graphene (GO) improved the mechanical properties of the composite membrane. Meantime, the composite membrane possessed stable hydrophobicity and lipophilicity, which was beneficial for separating water/viscous crude oil mixtures. Owing to the controllable pore structure and special wetting behavior, the water-in-oil emulsion was successfully separated. Importantly, the separation rates of the water/crude oil mixtures under the electrothermal effect was 2340 kg·m−2·h−1·bar−1. Thus, this study provides a new method for preparing hydrophobic sandwich-like PVDF/rGO/PDMS composite membrane with electrothermal/photothermal effects, which has significant potential for engineering applications in high-viscosity crude oil removal and water-in-oil emulsion separation. [Display omitted] • A hydrophobic sandwich structure PVDF/rGO/PDMS composite membrane was constructed. • Electrospinning promoted the binding of GO with PVDF membrane. • The composite membrane possessed super fast electric heating and photothermal conversion capability. • The composite membrane showed a high speed at separation viscous crude oil from water. • The effective separation of water-in-oil emulsion was successfully achieved. [ABSTRACT FROM AUTHOR]

Recently, the crude oil spill has brought inevitable harm to the global ecological environment. Due to the high-viscosity crude oil, it is wise to take advantage of the photothermal/electrothermal effects of the membrane to separate the crude oil from the water. However, the functional separation membrane always suffers from low photothermal/electrothermal effects and poor stability. Herein, the vinyl polyvinylidene fluoride/mercapto carbon nanotubes@vinyl-terminated polydimethylsiloxane (PVDF-a/CNT-s@PDMS) membrane with fast photothermal/electrothermal effects and organic absorption property was successfully prepared by electrospinning and multi-layer loading method. The prepared PVDF-a/CNT-s@PDMS membrane resisted a variety of liquids and had stable superhydrophobicity (WCA = 156°). Furthermore, the membrane maintained superhydrophobicity even suffer from water and milk under the applied voltage condition. After 100 wear resistance tests, the membrane maintained stable superhydrophobicity and the separation rate remained unchanged. The surface temperature of the membrane rapidly approached to the maximum temperature in 30 s, showing a rapid photothermal/electrothermal effects, and the average separation rate of crude oil was 1185 kg m−2 h−1·bar−1. Meanwhile, the membrane exhibited outstanding efficiency for separate immiscible oil-water mixtures. Importantly, the incorporation of the sulfhydryl group enhanced the special ability of the composite membrane to adsorb organic dyes from oil phase. Therefore, the PVDF-a/CNT-s@PDMS membrane has a wide range of potential application in the domain of oil-water separation. [Display omitted] • The superhydrophobic membrane exhibited high stability toward abrasion. • The obtained membrane possessed fast photothermal/electrothermal response. • The membrane effectively achieved various oil/water mixture separation. • The membrane possessed ability for the adsorption of organic dyes from the oil phase. [ABSTRACT FROM AUTHOR]