Effect of coagulation pretreatment on the fouling of ultrafiltration membrane.
The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter (NOM). A relatively higher molecular weight (MW) of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.
Dong
Bing-Zhi
BZ
State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China. dongbingzhi@online.sh.cn
Chen
Yan
Y
Gao
Nai-Yun
NY
Fan
Jin-Chu
JC
D000534:Alum Compounds / Q000737:chemistry*; D005591:Chemical Fractionation; D005427:Flocculation; D057927:Hydrophobic and Hydrophilic Interactions; D007475:Ion Exchange Resins / Q000737:chemistry; D009391:Nephelometry and Turbidimetry; D014462:Ultrafiltration; D014873:Water Pollutants / Q000737:chemistry* / Q000302:isolation & purification; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods
D000534:Alum Compounds; D007475:Ion Exchange Resins; D014873:Water Pollutants; C041524:aluminum sulfate