Influence of floc dynamic protection layer on alleviating ultrafiltration membrane fouling induced by humic substances  

作　　者：Baiwen Ma Siqi Wu Bodong Wang Zenglu Qi Yaohui Bai Huijuan Liu Jiuhui Qu Ruijun Wu 

机构地区：[1]Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,100085,China [2]University of Chinese Academy of Sciences,Beijing,100049,China [3]School of Environmental and Municipal Engineering,Xi’an University of Architecture and Technology,Xi'an,710055,China [4]School of Environment,State Key Joint Laboratory of Environment Simulation and Pollution Control,Tsinghua University,Beijing,100084,China [5]Research Center for Water Quality and Ecology,Tsinghua University,Beijing,100084,China [6]State Key Laboratory of Membrane Materials and Membrane Applications,Tianjin Motimo Membrane Technology Co.,Ltd.,Tianjin,300457,China

出　　处：《Journal of Environmental Sciences》2020年第4期10-19,共10页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation for Young Scientists of China(No.51608514);the Funds for International Cooperation and Exchange of the National Natural Science Foundation of China(No.51820105011);the National Key R&D Program of China(No.2016YFC0400802);the Program of the Youth Innovation Promotion Association of Chinese Academy of Sciences

摘　　要：Cake layer formation is inevitable over time for ultrafiltration(UF)membrane-based drinking water treatment.Although the cake layer is always considered to cause membrane fouling,it can also act as a"dynamic protection layer",as it further adsorbs pollutants and dramatically reduces their chance of getting to the membrane surface.Here,the UF membrane fouling performance was investigated with pre-deposited loose flocs in the presence of humic acid(HA).The results showed that the floc dynamic protection layer played an important role in removing HA.The higher the solution pH,the more negative the floc charge,resulting in lower HA removal efficiency due to the electrostatic repulsion and large pore size of the floc layer.With decreasing solution pH,a positively charged floc dynamic protection layer was formed,and more HA molecules were adsorbed.The potential reasons were ascribed to the smaller floc size,greater positive charge,and higher roughness of the floc layer.However,similar membrane fouling performance was also observed for the negative and positive floc dynamic protection layers due to their strong looseness characteristics.In addition,the molecular weight(MW)distribution of HA also played an important role in UF membrane fouling behavior.For the small MW HA molecules,the chance of forming a loose cake layer was high with a negatively charged floc dynamic protection layer,while for the large MW HA molecules it was high with a positively charged floc dynamic protection layer.As a result,slight UF membrane fouling was induced.

关 键 词：ULTRAFILTRATION Floc dynamic protection layer Humic substances Fouling alleviation 

分 类 号：TU991.2[建筑科学—市政工程]