反洗水组分对PVDF超滤膜污染的影响

摘要

In order to investigate the contribution of different components in the backwash water to the removal of membrane fouling,the humic acid solution was used as filter media and periodic filter backwashing experiment was carried out with single membrane in this experiment.The experimental results show that small molecular organic com-pounds in backwash water have little effect on membrane flux recovery and reverse washing efficiency compared with pure water.However,metal cations such as Ca2+and Na+can produce charge shielding and bridge effect on the inner and outer walls of the hollow fiber membrane,which strengthen the accumulation of pollutants on the surface of the membrane and lead to a more serious irreversible fouling.AFM picture shows that the removal of the membrane surface contaminants becomes more difficult with the addition of metal cations such as Ca2+and Na+in the backwash water.This experiment provides a new way of method for controlling membrane pollution by regulating the water components of the backwash water.%为了考察反洗水中不同组分对膜表面污染的去除贡献情况,以腐殖酸溶液为过滤介质,采用单根膜丝进行了周期性过滤反洗实验.实验结果表明:与纯水相比,反洗水中小分子有机物对膜通量恢复和反洗效率影响并不大,但Ca2+、Na+等金属阳离子能够在中空纤维膜的内外壁上产生电荷屏蔽和吸附架桥效应,强化了污染物在膜表面的累积,导致了更为严重的不可逆污染;AFM图片说明,膜表面污染物的去除随着反洗水中Ca2+、Na+等金属阳离子的加入变得更为困难,该实验为通过调控反洗水组分来控制膜污染提供了一种新的思路和方法.