混凝缓解纳滤膜有机污染研究

Study on nanofiltration membrane fouling prevention by coagulation

对3种混凝剂去除水中有机物的性能进行了对比,确定了适用于纳滤预处理的混凝剂种类。研究了混凝剂投加量、沉淀时间对纳滤膜通量衰减的影响,并对纳滤膜有机污染物的亲水性进行分析。研究结果表明较高的混凝剂投加量能提高有机物的去除率,但混凝剂本身会造成纳滤膜污染,引起通量的下降,而沉淀过程不能完全分离水中的微小絮体。研究还表明混凝过程对水中有机物的去除具有选择性,对疏水性有机物的去除率明显高于亲水性有机物。将混凝与活性炭过滤结合能够显著缓解纳滤通量衰减过程。

Organic contaminants removal efficiencies of three different coagulants were compared. The best one for nanofiltration membrane fouling prevention was selected to investigate in-fluence of dosage and precipitation time. Furthermore hydrophilism of membrane fouling was checked. The results indicated that a higher dosage of coagulants was able to improve removal rate of organic matters in raw water, on the other hand coagulants caused decline of nanofiltration flux. Besides, the sedimentation process was not able to separate micro particulate form. In this study removal rate of organics with different hydrophilism was also investigated. An obviously higher re moval of hydrophobic organic compounds than hydrophilic organics was obtained. In order to im prove organic contaminants removal rate BAC was selected to filtrate effluent of coagulation. The hybrid process was able to slow down membrane fouling effectively.