聚偏氟乙烯微滤膜性能及结构

研究了亲水性聚偏氟乙烯(PVDF)微滤膜的结构、过滤性能、亲水性和清水反冲洗效果。膜结构由SEM照片和泡点-流速法测定的膜孔径分布表征,通过过滤双蒸水和BSA缓冲液来表征膜的通量、过滤衰减和清洗恢复性能,并对BSA液过滤前后膜结构进行了对比分析,膜亲水性由水接触角表征。试验结果表明,膜孔径分布范围在0.22～0.27μm之间;初始静态水接触角为61.5°,水滴在80 s内渗入膜中;膜初始水通量为1 651.0 L.m-2.h-1,过滤浓度1 g.L-1pH=7.0的BSA液时膜通量随着过滤时间的延长而不断减小,最后达到一稳定的平衡通量229.3 L.m-2.h-1;平均过滤阻力构成分别为:Rp占70.0%,Rm占19.5%,Ri占7.3%,Re占3.1%;污染膜可通过清水反冲洗来恢复,4次循环后膜通量可恢复至1 008.9 L.m-2.h-1,膜通量恢复率达到61.1%。

STRUCTURE AND PROPERTIES OF PVDF MICROFILTRATION MEMBRANE

The PVDF microfiltration membrane structure,filtering properties,hydrophilicity and antifouling property were studied.The membrane structure was characterized by SEM and the pore size distribution measured by Bubble point-mean flow method.The distilled water and BSA buffer flux of the membrane,its flux deterioration and membrane backflush effect were measured.Membrane structure before and after BSA filtration were compared.Hydrophilicity of the membrane was characterized by water contact angle.The results show that the pore size distribution of the membrane is between 0.22～0.27 μm.The initial water contact angle is 61.5°and water drop penetrated into membrane in 80 sec.Membrane initial water flux is 1 651.0 L·m-2 ·h-1.The membrane flux of 1 g·L-1 BSA solution decreased during the filtration process and finally reached pseudo-stable 229.3 L·m-2 ·h-1.Rp accounts for 70% of the filtering resistance,and Rm 19.5%,Ri 7.3%,Re 3.1%.The polluted membrane can be recovered only by water backflush and after four cycles the water flux can be recovered to 1 008.9 L·m-2 ·h-1,which was 61.1% of the intial membrane flux.