改性沸石预涂层改善超滤膜通量研究  

Modified Powdered Zeolite Pre-coating Process for Improvement of Ultra-filtration Membrane Flux

作　　者：汪力[1] 董秉直[1] 夏丽华[1] 高乃云[1] 

机构地区：[1]同济大学污染控制与资源化研究国家重点试验室,上海200092

出　　处：《中国给水排水》2005年第12期5-9,共5页China Water & Wastewater

基　　金：国家高技术研究发展计划(863)项目(2002AA601130);国家科技攻关计划重大项目(2003BA808A17)

摘　　要：采用改性粉末沸石对超滤膜表面进行预涂层,研究了预涂层工艺对改善膜通量的作用与机理,结果表明:沸石经酸法改性后,比表面积增加,表面负电性降低,是合适的涂层物质。改性粉末沸石与超滤膜联用对有机物的去除具有协同作用,在改性沸石涂层量为300mg/L的条件下,对CODMn的去除率为29.6%,对UV254的去除率为21.8%,比原水经膜直接过滤有较大程度提高。沸石预涂层能够使膜表面和膜孔内的有机物浓度降低,因而维持较高膜通量,有效防止了膜污染。改性沸石预涂层主要增加了对分子质量<3000u有机物的去除率,这对提高膜通量的贡献较大。表面呈弱负电性的改性沸石能够形成结构松散、孔隙较大的滤饼层,反冲洗时容易被冲洗掉,膜通量能够得到很好恢复。Modified powdered zeolite was pre-coated on the ultrafiltration membrane. The effect and mechanism of zeolite pre-coating process on improving uhrafihration membrane flux were studied. The result shows that the modified zeolite is increased in specific surface area and decreased in surface negative charge, and is a suitable pre-coating material. The combined use of modified powdered zeolite and uhrafihration membrane has synergistic effect on organics removal. Under the pre-coating dosage of 300 mg/L, the removal rate of CODMn and UV254 is 29.6% and 21.8% respectively, much more than that of direct filtration of uhrafihration membrane. The modified zeolite pre-coating process can improve membrane flux and prevent effectively the membrane fouling by decreasing the organics concentration both on the surface and in the pore of membrane. The removal rate of organics with molecular weight less than 3 000 u modified is mainly zeolite wi can be easily flush increased, which makes th weak negative charge ed away in backwashing, more contribution to the improvement of membrane flux. The on surface can form the loosened and porous filter cake that so that the membrane flux can be recovered perfectly.

关 键 词：改性粉末沸石 预涂层 超滤膜 膜通量 

分 类 号：TU991.2[建筑科学—市政工程]