Preparation Of Superwetting Composite Membrane For The Application Of Oil/Water Separation

Nowadays,oily wastewater has become one of serious problems in environment.Membrane separation technology has shown great promise in oil/water separation because of its many advantages,such as high separation efficiency,saving energy,space saving,and without secondary pollution.Nevertheless,membrane separation technology is still far from being applied in oil/water separation due to its membrane oil-fouling.Thus,supperweting membrane materials with anti-fouling property,can solve oil-fouling problem of membrane.In this paper,based on superwetting surface,various superwetting membranes were developed by controlling of the morphology and chemical structure of the membrane for dealing with various oily wastewater in this work.As follows:Inspired by mussel,a novel and simple method is exploited to design a novel polymer composite membrane with hydrophilic groups and nano-microspheres hierarchical structure by depositing polydopamine(PDA)on hydrophobic polytetrafluoroethylene(PTFE)membrane surface in tetrahydrofuran(THF)-Tris buffer mixture.According to the results,the prepared membrane possesses superhydrophilic and underwater superoleophobic property.Therefore,the as-prepared membranes can be applied in varieties of oil-in-water emulsions separation with high oil/water separation efficiency(>99.0%)and good anti-fouling property.A CA/PVA/Si composite mesh membrane with an ordered porous structure is fabricated via a facile direct inkjet writing(DIW)3D printing technology.As a result,the water contact angle and underwater oil contact angles of the printed membrane are18.14±2.61°and 159.14±0.59°,respectively.Thus,the printed membrane exhibits superhydrophilic and underwater superoleophobic characteristics,and high oil/water separation efficiency about 99.0%for oil/water mixture driven by gravity.Base on hydrosilylation reaction,a facile approach is developed for scaling the production of SHBOI porous materials by the deposition of superhydrophobic and superoleophilic PDMS-co-PMHS coating onto porous materials(sponge(SP),fiber paper(FP),glass fiber membrane(GF))via a surface coating method.As a result,PDMS-co-PMHS@SP possesses superhydrophobic and superoleophilic characteristics,high oil-adsorption capacity(up to 143 times its original weight)and excellent recyclability.PDMS-co-PMHS@FP can efficiently separate a series of immiscible oil/water mixtures in a single-step based on its superhydrophobic and superoleophilic characteristics and high oil or organic solvents fluxes(about 2000–3000 L.m^-2.h^-1).In addition,PDMS-co-PMHS@GF membrane exhibits superhydrophobic and superoleophilic characteristics and good water rejection(?99.90%)for separating water-in-oil emulsions under gravity-drivenA facile,environment-friendly,and one-step spraying method is developed for fabricating an omniphobic PVDF composite membrane with re-entrant structure and low surface energy.As a result,the prepared membrane possesses omniphobic characteristics and superior anti-wetting and anti-fouling characteristics even to the saline feed solution with oil pollutants in MD process.