Hydrophilic Modification And Water Filtration Performance Of PVC Ultrafiltration Membranes

Ultra-filtration(UF) membrane technologies have been widely applied in water treatment field. But the applications are greatly refrained because of membrane fouling and the high cost in water treatment and reuse engineering. In this paper, the preparation of the nano-Al2O3/vinyl acetate/PVC membrane by phase inversion process were firstly proposed and studied in order to improve the UF application for water treatment and reuse.In the present research, the PVC, a kind of inexpensive materials for membrane preparation was selected to reduce the cost of membrane products. Nano-Al2O3 was used to modify the membrane hydrophilic and anti-fouling performance. Vinyl acetate was selected to improve membrane extension performance. With the membrane micro-structure characterization, it was found that the modified membrane surface was dotted with tiny uniform pores. The upper layer was the dense epidermis and the lower one with holes was the supporting layer. It proved that the membrane cross-section structure was a typical non-symmetrical structure.Several different components membranes were comparatively studied with pure water flux testing. The nano-Al2O3/vinyl acetate/PVC composite membrane showed the largest water flux which was upto 259.9 L·m2·h)-1,and the smallest contact angle of 54.26°, which means it had the best hydrophilic performance. This phenomenon can well match the water flux test results. Mechanism analysis showed that the dosing of hydrophilic nano-particle Al2O3 can greatly improve the hydrophilic performance of membrane surface, which resulted in the lower contact angle and higher surface energy. Then the surface hydrophilic performance was enhanced.1% a-amylase solution,beer and inorganic mineral kaolin solution were filtrated by membranes as feed solution. The relation of flux and filtration time was studied. It is found that nano-Al2O3/vinyl acetate/PVC composite membrane spent the shortest time to get stable flux.And the stable flux was higher than others. The nano-Al2O3/vinyl acetate/PVC composite membrane showed very good anti-fouling performanceThrough the comprehensive study on filtration, the membrane preparation compositions were determined as following:N,N-dimethylacetamide(DMAC) concentration of 82～86%;polyvinyl chloride(PVC) concentration of 8～10%; vinyl acetate(VAC) concentration of 1.2～1.4%; nano-Al2O3 concentration of 1.4～1.8%;SHMP concentration of 0.6～1.0%;polyvinylpyrrolidone(PVP) concentration of 3.1～3.3%.