Synthesis Of Superhydrophilic Materials And Their Application In Oil-Water Separation

In recent years,a large number of oil spills and the discharge of oily,wastewater have caused serious harm to the ecological environment and human health.Therefore,it is very important to find a treatment method to solve the oil pollution and industrial wastewater.The use of "water-removing" and "oil-removing" materials is a very effective way to solve oil pollution and industrial wastewater.Among them,the "oil-removing"superhydrophobic-superoleophilic material realizes oil-water separation by adsorption or filtration of oil,however,the material is easily contaminated or even blocked by oil,resulting in inefficient separation.The "water-removing" superhydrophilic-underwater superoleophobic material,through th e adsorption or filtration of water,makes the oil be blocked from the surface of the material,the material is not easy to be polluted by oil.Therefore,the"water-removing" superhydrophilic-underwater superoleophobic materials have the advantages of high flux,good oil resistance and durability.Based on this research background,this paper selects copper foam,fabric,cotton and PVDF membranes as substrates,and modifies them with common substances containing superhydrophilic groups to prepare superhydrophilic-underwater superoleophobic materials.It was tested for performance,oil-water separation and emulsion separation.The main research contents of this paper are as follows:(1)The superhydrophilic-underwater superoleophobic copper foam was successfully prepared by surface oxidation and hydrothermal methods.The superhydrophilic-underwater superoleophobic copper foam has excellent superhydrophilicity and underwater separation efficiency in oil-water separation and durability,the oil-water separation efficiency can be as high as 99%,and it has good circulation and high flow(24129 L m-2 h-1).In addition,the superhydrophilic-underwater superoleophobic copper foam surface has the advantage of working for a long time under harsh environments or severe mechanical wear,showing excellent corrosion resistance and mechanical durability.Therefore,the prepared superhydrophilicunderwater superoleophobic copper foam can be used for oil spill cleanup,thereby realizing the separation of oil-water mixture,which is of great significance in real life.(2)Using cheap and easily available egg white and phytic acid as the main raw materials,as well as ground egg shell and TiO2 particles to build a composite system,it was loaded on fabric,cotton and PVDF membrane substrate by simple and easy-to-use impregnation method,and the preparation of superhydrophilic-underwater superoleophobic material was successfully realized.The prepared superhydrophilic-underwater superoleophobic material has excellent hydrophilicity and underwater superoleophobic.The contact angle of various oils underwater is greater than 150° and the rolling angle is less than 5°,so it has good oil pollution prevention performance.The superhydrophilic-underwater superoleophobic material can achieve highefficiency separation of various oil-in-water emulsions(above 98%)and oil-water mixtures(above 98%).It has good stability under strong acid and alkali and different temperatures,and can be used repeatedly.In the preparation process of this kind of superhydrophilic-underwater superoleophobic material,biomass egg white and egg shell are used as raw materials,and the efficient preparation of environment-friendly superhydrophilic-underwater superoleophobic material is realized.It has a good application prospect in the treatment of domestic wastewater.