Fabrication And Studies Of Carbon Based Composite Membrane With Superwettability Toward Oil/Water Separation

In recent years,with the rapid development of industry and the enhancement of human's level of life,the discharge of oily wastewater and the frequent occurrence of offshore oil leakage events have triggered severe water pollution.How to remove oil from water and achieve marine pollution resistance have become a hot topic in current research.The super wetting separation membrane hold micro-nano-sized pore structure,simple preparation,low cost and superior separation effeciency,which promotes the development of superwetting separation materials.However,most materials can only complete mixtures separation or with a single function drawbacks and so on.When facing complex sewage system,it is incapable to handle various types of emulsions and remove other pollutants in water according to actual requirement.Under above circumstance,this research used carbon nanotubes as base materials to complex with other substances by radical polymerization and hydration-dehydration methods,respectively.Carbon nanotube composite membrane with different wetting properties were prepared by vacuum assisted filtration technology,which expanded its research in the field of oil/water separation and provided a new avenue for fabrication of high efficiency,stability and multifunctional oil/water separation membranes.The main contents about this study are as follows:1.Hydrophilic CNTs modified by polyacrylic acid(CNTs-PAA)were obtained by grafting polyacrylic acid(PAA)onto carbon nanotubes(CNTs).The CNTs-PAA was pumped onto the filter membrane by filtration technology,and subsequently loaded a layer of catalytic MIL101(Fe)@Pt particles to prepare a both oil/water separation and dye molecule degradation CNTs-PAA/MIL101(Fe)@Pt separation membrane.Moreover,the flux of simultaneously separating silicion oil-in-water emulsion and degrading methylene blue attain as high as 11000 Lm^-2h^-1bar^-1,which exceeds most multifunctional separation membranes.The separation efficiency and degradation efficiency can reach 98.8%and 98.5%,respectively.The construction of the hybrid membrane expands the research of carbon-based composite membrane in the field of multifunctional oil/water separation.2.CNTs/TiO₂ were prepared by mixing carbon nanotubes(CNTs)with titanium oxysulfate(TiOSO₄)and in-situ compounding titanium dioxide(TiO₂)on CNTs by hydration dehydration method.The CNTs/TiO₂composite membrane were prepared via vacuum assisted filtration,and exhibit superhydrophilic/superoleophilic,superoleophobic underwater/superhydrophobic underoil superwettability.Through prewetting strategy,various oil/water mixtures and emulsions can be successful separation.Among them,the separation flux of water-in-dichloromethane emulsion can reach 40000 Lm^-2h^-1bar^-1,which higher than most oil/water separation membranes and separation efficiency reach 98.9%.While separating light oil/water mixtures,It can efficiently absorb soluble dye molecule,such as methylene blue(98.6%),Congo red(89.1%),Rhodamine B(85.9%)and Evans Blue(80%).Moreover,CNTs/TiO₂separation membrane hold good corrosion resistance and stability,which can satisfy on-demand oil/water separation and dye absorption.