Preparation Of High Alumina Loaded Composite Ultrafiltration Membrane And Its Application In Oil-water Separatio

In recent years,with the rapid development of industry and agriculture,the arbitrary discharge of oily wastewater and the frequent occurrence of offshore oil spill accidents have posed a great danger to the global ecological environment and human health.At present,the traditional oil-water separation technologies,such as gravity separation method,flotation method and adsorption method,have the disadvantages of limited treatment capacity,complicated operation and easy to cause secondary pollution when treating oily wastewater.As an emerging method for treating oily wastewater,membrane separation technology has been widely used in the field of water treatment because of its simple operation,high separation efficiency,environmental protection and no pollution.In this paper,highly loaded alumina/polysulfone composite ultrafiltration membranes were successfully prepared by nonsolvent induced phase separation（NIPS）using polysulfone（PSF）as membrane material and alumina（Al₂O₃）as hydrophilic additive,and applied to the treatment of oil-water emulsion（O/W）.The effects of the composition ratio of Al₂O₃ and PSF on the structural morphology,porosity,average pore size,mechanical property,wettability,oil-water emulsion separation performance and antifouling performance of the composite membrane were investigated,and finally the Al₂O₃/PSF composite ultrafiltration membrane with good separation performance and antifouling performance was developed.The results showed that when the mass ratio of Al₂O₃/PSF was 7:1,the water contact angle and underwater oil contact angle of the membranes were 45°and 132°,respectively,which exhibits good underwater oleophobic performance.The pure water flux of the membrane was up to 1550 L m^-2·h^-1·bar^-1,and its stable permeability to soybean oil emulsion and silicone oil emulsion were 362 and 316 L·m^-2·h^-1·bar^-1,respectively,and its oil rejection rate for oil-water emulsions was higher than 99%,demonstrating the membrane’s good separation effect on oil-in-water emulsion.After one cycle of fouling-cleaning test,the results showed that the membrane have good antifouling performance and regeneration performance.Meanwhile,the effects of different air bath times on the structure and performance of the composite membranes were investigated on this basis by studying the phase transformation process.The results showed that when the air bath time was 5 min,the porosity and average pore size of the membrane were 74.49%and 24.8 nm,respectively,and the pure water flux of the membrane reached the highest 1980 L·m^-2·h^-1·bar^-1,and the stable permeability to soybean oil emulsion and silicone oil emulsion were 457 and344 L·m^-2·h^-1·bar^-1,respectively,and its oil rejection rate from oil-water emulsion was higher than 99%,demonstrating its good effect on the separation of oil-in-water emulsion.