PES/PAN膜在MBR中膜污染机理及抗污染性能

采用液-固相转化法,以聚醚砜(PES)、氯化锂(LiCl)、聚乙烯吡咯烷酮(PVP)和N,N-二甲基乙酰胺(DMAc)为原料制备PES膜,并在体系中添加聚丙烯腈(PAN)制备PES/PAN膜。在操作温度25℃,操作压力90KPa条件下制得的PES/PAN膜、自制PES膜和商品PES超滤膜分别为222L/(m·2h)左右,130L/(m·2h)左右,82L/(m·2h)左右。通过膜生物反应器中膜阻力的测定,表明膜污染主要由沉积层引起的,另一方面长期运行膜孔堵塞也是阻力增大的原因。在MBR中运行时,PES/PAN膜、自制PES膜和商品PES超滤膜膜通量的衰减速率分别为0.2559L/(m·2h·min)、0.3366L/(m·2h·min)、0.3539L/(m·2h·min),PES/PAN膜通量衰减最慢;在MBR中运行15d后,经过化学清洗,PES/PAN膜、自制PES膜和商品PES超滤膜纯水通量恢复率分别为83.75%、63.58%、61.32%,PES/PAN膜通量恢复率最大,抗污染性优于PES膜。

Membrane Fouling Mechanism and Anti-fouling Performance of PES/PAN Membrane in Membrane Bioreactor

Polyethersulfone (PES) membrane was prepared by liquid-solid phase inversion method with PES,LiCl,polyvinylpyrrolidone (PVP) and dimethylacetamide (DMAc). And polyacrylonitrile (PAN) was added into the system to prepare PES/PAN membrane. The water flux of PES/PAN membrane,PES membrane and PES ultrafiltration (UF) membrane were about 222L/(m2·h),130L/(m2·h) and 82L/(m2·h) respectively under the operational conditions of 25℃ and 90KPa. According to results of membrane resistance determination in a membrane bioreactor,it was found that membrane fouling was mainly attributed to concentration polarization layer and gel layer,and during a long term operation,membrane hole blockage was the reason for resistance addition. In MBR the decay rates of membrane flux of PES/PAN membrane,PES membrane and PES ultrafiltration (UF) membrane were about 0.2559L/(m2·h·min),0.3366L/(m2·h·min) and 0.3539 L/(mm2·h·min) respectively,the membrane flux of PES/PAN membrane decreased most slowly. After membranes ran in MBR for 15d,by chemical cleaning,pure water flux recovery rate of PES/PAN membrane,PES membrane and PES UF membrane were about 83.75%,63.58% and 61.32% respectively,with pure water flux recovery rate of PES/PAN membrane as the maximum and anti-fouling performance of PES/PAN membrane better than PES membrane.