Fabrication Of Superhydrophilic And Underwater Superoleophobic Organic-inorganic Composite Membrane And Research On Its Performance

Water is the source of life,but the whole world is currently facing water scarcity and water pollution.For the two major problems about water resource,on the one hand,water conservation should be carried out.On the other hand,measures should be taken to purify the polluted water,and“turn waste into treasure”,to realize the reuse of water resource.Among the methods for water treatment,the method of membrane treatment is undoubtedly a means of having little impact on the environment,low cost,and high operability.Researchers are in full swing to carry out various researches on membranes for oil-water separation,but now there are still some overcome difficulties,such as expensive materials for preparing membranes,environmentally harmful pollutants produced during the preparation process,and complicated preparation processes,which have seriously affected the application of membrane separation materials in oil-water separation.Therefore,it is necessary to continue to conduct in-depth research on membrane separation materials,and strive to achieve low cost,high recycling rate,high durability,and strong anti-pollution.In this work,the problems of film swelling,membrane fouling and durability were studied.The stainless steel mesh was used as the substrate,and the superhydrophilic/underwater superoleophobic membrane for oil-water separation was prepared by impregnation method and organic-inorganic hybrid method.The details are as follows:?1?Preparation and properties of superhydrophilic/underwater superoleophobic membrane for oil-water separation.A stainless steel wire mesh was used as supporting material,and Ag₂O micron particles were prepared to roughen the surface thereof to obtain a stainless steel wire mesh having micron roughness structure.In order to improve the bonding strength of the Ag₂O particles to the stainless steel wire mesh,it was treated with a good adhesion dopamine before roughening the stainless steel wire mesh.The roughened stainless steel wire mesh was immersed in an aqueous solution of a hydrophilic polyvinyl alcohol of a suitable concentration to thereby obtain an oil-water separation film.The prepared oil-water separation membrane can effectively separate many kinds of oily sewage,the separation efficiency is more than 95%,the contact angle of the oil under water was more than 150°,the contact angle to water was about 0°.The membrane was superoleophobic under the water and superhydrophilic.?2?Preparation and properties of antifouling and anti-swelling superhydrophilic/underwater superoleophobic membrane for oil-water separation.The water swellability of the polyvinyl alcohol was improved by the esterification reaction,so that the polyvinyl alcohol had high mechanical strength and swelling resistance.The porous silica nanoparticles were prepared by sol-gel method and template removal method,and then modified with a silane coupling agent and dopamine to obtain target porous silica particles.The roughened stainless steel wire mesh was immersed in an optimum ratio of the casting solution to obtain membrane for oil-water separation.The obtained oil-water separation membrane can be superhydrophilic and underwater superoleophobic,and the oil-water separation efficiency was 98.8%.The antifouling and anti-swelling tests were carried out,and the results were all expected.