Preparation,characterization And Oil-water Separation Properties Of Hydrophobic And Oleophobic Ceramic Composite Membranes

The water pollution has become a serious problem by human daily life and factory with the advance of science and technology and the improvement of human life,What’s more,one of the most serious water pollution is oily wastewater.On the other hand,the water in the oil would lead to the oil become murky with the emulsification and the increase of oil viscoelasticity will aggravate the corrosion of the equipment.So we should explore more effective way for oil-water separation to protect our environment and reuse or recycle our water resource.The emergency of membrane separation technology is a good way to resolve the oil-water separation.In this paper,the hydrophobic ceramic composite membranes were prepared via the decomposition of fluoride on the surface of alumina membrane during the sintering process of PTFE powder and ceramic membrane in the pure nitrogen.The modified membranes were characterized by SEM,FTIR,TG,Chemical stability and water contact angle measurements.The water contact angle of hydrophobic ceramic composite membrane was high as 148°,the result of FTIR,XPS,TG shows that the fluoride layer was on the surface of hydrophobic ceramic membrane.The granular fluoride material on the hydrophobic ceramic membrane could be observed by SEM,however,the surface of alumina ceramic membrane was very smooth.The water contact angle of hydrophobic ceramic membrane which was immersed into oil in 24 h only decreased 7° than before.It means that hydrophobic of ceramic membrane could be used for oil-water separation well.The effects of feed water content and transmembrane pressure on the hydrophobic ceramic membrane separation process were investigated.Either increasing the operation pressure or decreasing the feed water content could improve the flux of the hydrophobic ceramic membrane.The optimum preparation conditions of hydrophobic ceramic membrane were obtained with the sintering temperature of 400℃,the sintering time of 7h,the heating rate at 4℃/min and the optimum conditions of the separation experiment were obtained with the transmembrane pressure of 0.1MPa,feed water content of 1%.it was also showed that the original permeate flux was 12.85Kg/(m2·h)and the water rejection was stable as high as 98.42%.In this paper,the underwater superoleophobic ceramic membrane was obtained by the cross linking reaction of DA and PEI at different reaction time in DA or PEI solution.The modifiedmembranes were characterized by SEM,XPS,FTIR,and underwater oil contact angle measurements.The underwater oil contact angle of superoleophobic ceramic composite membrane was high as 152°,the result of FTIR,XPS shows that the cross linking product of PEI and DA consist on the surface of superoleophobic ceramic membrane.The granular material of product on the superoleophobic ceramic membrane could be observed by SEM,however,the surface of alumina ceramic membrane was very smooth.The membrane pore size fell sharply means the membrane pore and surface was full with granular material.The effects of the reaction time ratio of DA with PEI on the superoleophobic ceramic membrane separation process were investigated.The membrane pore size and water flux were decreased with the reaction time ratio of DA and PEI increased,but the oil rejection was increased a little.The optimum preparation conditions of superoleophobic ceramic membrane were obtained with the reaction time in DA solution at 24 h and in PEI solution at 8h.the optimum conditions of the separation experiment were obtained with the transmembrane pressure of 0.1MPa,oil content of 1%.it was also showed that the original permeate flux was298Kg/(m2·h)and the oil rejection was stable as high as 98.7%.