New insights into membrane fouling in coagulation-ultrafiltration by cake characteristics analysis:A case study with PACl-Al_(13)and PACl  

作　　者：Mingyao Xu Wei Ju Zhenbei Wang Jun Nan Fei Qi Chen Li Yatao Liu Wei Li Dezhi Sun 

机构地区：[1]Beijing Key Lab for Source Control Technology of Water Pollution,College of Environmental Science and Engineering,Beijing Forestry University,Beijing 100083,China [2]Beijing Forestry University Science Co.,Ltd.,Beijing 100085,China [3]Skate Key Laboratory of Urban Water Resource and Environment,School of Environment,Harbin Institute of Technology,Harbin 150090,China [4]Research Center for Eco-environmental Engineering,Dongguan University of Technology,Dongguan 523106,China

出　　处：《Journal of Environmental Sciences》2024年第12期217-225,共9页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.52100002,52200035,22076012 and51878047);the Open Project of State Key Laboratory of Urban Water Resource and Environment(No.QA202014);the Yangtze River Joint Research Phase II Program(No.2022-LHYJ-02-0510-02);the National Key Research and Development Program of China(No.2021YFE0100800);the Beijing Forestry University Outstanding Young Talent Cultivation Project(No.2019JQ03008);the Beijing Municipal Education Commission through the Innovative Transdisciplinary Program“Ecological Restoration Engineering”(No.GJJXK210102);the China Postdoctoral Science Foundation(No.2021M700448).

摘　　要：Membrane fouling is a bottleneck issue that hindered the further application of ultrafiltration technology.To alleviate membrane fouling,coagulation-ultrafiltration(C-UF)process using polyaluminum chloride(PACl)and PACl-Al_(13)with high proportion of Al_(13)O_(4)(OH)_(24)^(7+)as coagulants,respectively,were investigated at various pH conditions.Results indicated that an increase in solution pH contributed to larger floc size and looser floc structure for both PACl and PACl-Al_(13).It was conducive to the formation of more porous cake,as evidenced by mean pore area and pore area distribution of cake,leading to lower reversible fouling.Furthermore,humic acid(HA)removal presented a trend of first increasing and then decreasing with the increase of pH.The optimal HA removal was achieved at pH 6 regardless of coagulant type,suggesting that the slightest irreversible fouling should be occurred at this point.Interestingly,the irreversible fouling with PACl coagulant achieved a minimum value at pH 9,while the minimal irreversible fouling with PACl-Al_(13)was observed at pH 6.We speculated that the cake formed by PACl could further intercept HA prior to UF process at alkaline pH.Furthermore,compared with PACl,PACl-Al_(13)had a stronger charge neutralization ability,thus contributing to more compact floc structure and higher HA removal at various pH conditions.By UF fractionation measurement,higher HA removal for PACl-Al_(13)was due to higher removal of HA with molecular weight less than 50 kDa.

关 键 词：Coagultion-ultrafiltration Floc properties Cake characteristics Molecular weight of HA Membrane fouling 

分 类 号：X703[环境科学与工程—环境工程]