超滤膜处理高藻水过程中天然颗粒物对膜污染的影响

摘要

超滤技术凭借其优异的截留分离能力,能够完全去除藻细胞且不会引起藻细胞的破裂,在处理高藻水时具有明显的技术优势.很多学者进行了超滤过程中藻细胞以及胞外有机物(EOM)的膜污染研究,但不足之处是没有综合考虑到天然水体中存在的颗粒物的影响.本研究采用高岭土代替水中颗粒物研究高岭土颗粒对藻类污染物的膜污染特性的影响.结果表明,对于藻细胞污染,高岭土能够改善藻细胞滤饼层孔隙率和可压缩性,从而减缓膜污染;对于EOM引起的膜污染,高岭土颗粒没有明显的改善效果,但是能够减少有机物的透过率,提高出水水质.在污染机理方面,对于高岭土和藻细胞及其组合污染物的过滤过程,滤饼层过滤为主要污染机理;对于EOM溶液及高岭土和EOM混合溶液,其污染机理主要是标准堵塞和滤饼层过滤.%Ultrafiltration,which can completely remove algal cells and not cause algal cell lysis,has obvious technical advantages in dealing with algae-rich water.Many researchers studied on algal organic removal and membrane fouling during algae-laden water treatment using UF,but the inadequacies were that the effects of particulate matter present in natural water were not taken into account.In this work,kaolin was used as the representive substitute of natural particles to study the effect of kaolin particles on the membrane fouling by algal foulants.It was found that the present of kaolin reduced the fouling caused by algal cells by improving the porosity and compressibility of the cake layer.However,kaolin particles did not significantly mitigate the fouling caused by EOM,but improved the water quality for reducing the permeability of organic matter.In terms of mechanisms for the fouling by kaolin,algae cells and their combined solutions,the cake filtration was the main mechanism;EOM and kaolin-EOM fouling was governed by multiple mechanisms with standard blocking and cake filtration dominating the fouling formation.