Preparation of poly(vinylidene fluoride) ultrafiltration membrane modified by nano-sized alumina and its antifouling performance

Organic-inorganic composite membranes were prepared by phase inversion process using nano-sized alumina (Al2O3) particles as inorganic additive uniformly dispersed in poly(vinylidene fluoride) (PVDF) in order to improve the flux and antifouling performances of PVDF ultrafiltration membrane. Contact angle between water and the membrane surface was measured by contact anglometer in order to characterize the hydrophlicity changing of the membrane surface. Porous dispersion of the membrane surface, the cross-sectional structures and nanometer particles distribution were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) respectively. Mechanical performances of membranes were measured by omnipotence electronic intensity measuring instrument (W-56). Antifouling performance of modified membranes was investigated by an ultrafiltration (UF) cup set. Contaminations on the fouled membranes were analyzed by gas chromatography and mass spectrum. Experimental results indicate that the modified membrane has favorable performances such as water flux, intensity and antifouling performances with 2% addition of nanometer Al2O3particulars. The addition of nanometer Al2O3particulars can not affect microstructures of the membrane's surface and cross-section. On the basis of keeping the traits of PVDF organic membranes, surface hydrophlicity properties and antifouling performances of modified membranes are improved significantly due to nano-sized particles addition.