Preparation Of Novel Superhydrophilic/underwater Superoleophobic Filter Membranes And Purification Of Oily Waste Water

In recent years,the maritime transportation industry has flourished,accompanied by the problem of oil-contaminated wastewater generated during the shipping process.In order to create a green and sustainable maritime navigation environment,efficient treatment of oil-contaminated wastewater has become a research hotspot.Traditional methods for treating oil-contaminated wastewater suffer from high energy consumption,low separation efficiency,and potential for secondary pollution.Inspired by bionics,researchers have prepared special superhydrophilic underwater superoleophobic membrane materials.However,the preparation process of these membrane materials is cumbersome and prone to membrane pollution during the treatment of oil-contaminated wastewater.Therefore,this thesis prepared two novel superhydrophilic underwater superoleophobic filter membranes,studied these two materials through characterization analysis and performance testing,and systematically investigated the purification effects of these two filter membranes on oil-contaminated wastewater.The main research results are as follows:（1）In order to develop environmentally friendly and low-cost oil-water separation materials,Mg²⁺was introduced to self-assemble with tannic acid（TA）and sodium alginate（SA）,and an ultra-thin coating was constructed on the surface of the hydrophobic substrate polyvinylidene fluoride（PVDF）membrane to achieve super-hydrophilic modification.A superhydrophilic underwater superoleophobic composite membrane（TMS-PVDF membrane）was prepared.The TMS-PVDF membrane showed good purification performance,and the separation efficiency of oil-water mixture and emulsified oil was99.9%.In addition,the TMS-PVDF membrane effectively solves the problem of low separation efficiency of super hydrophilic underwater super oleophobic materials,and realizes oil pollution pretreatment,which lays a foundation for further purification of emulsified oil in oily wastewater.（2）In order to develop membrane materials for efficient treatment of emulsified oil,a novel super hydrophilic underwater super oleophobic composite membrane（TAPE membrane）was prepared by simple impregnation with tannic acid（TA）and polyethylene glycol（PEG）as modifiers and polyvinylidene fluoride（PVDF）membrane as substrate.This modification method has the advantages of low cost and easy operation.The TAPE film has a porous micro-nano rough structure and the surface roughness is improved.After properly adjusting the content of tannic acid,the modified membrane showed superhydrophilicity and underwater superoleophobicity.Under certain operating pressure,the separation efficiency of TAPE membrane for oil-water mixture and emulsified oil can reach 99.9%,and the membrane flux for separating emulsified oil is 1146.4 L/（m²·h·bar）.The TAPE film has excellent stability.After 25 times of sandpaper abrasion,the underwater oil contact angle is still as high as 152°.In addition,the membrane also has excellent oil resistance and recyclability.The results of this study have solved the problems of cumbersome process,difficult treatment of emulsified oil and membrane fouling in traditional oily wastewater treatment,and have potential application prospects in the field of oily wastewater purification.