title: Comparative Evaluation of Aluminum Sulfate and Ferric Sulfate-Induced Coagulations as Pretreatment of Microfiltration for Treatment of Surface Water.
abstract: Two coagulants, aluminum sulfate and ferric chloride, were tested to reduce natural organic matter (NOM) as a pretreatment prior to polyvinylidene fluoride (PVDF) microfiltration (MF) membranes for potable water treatment. The results showed that the two coagulants exhibited different treatment performance in NOM removal. Molecular weight (MW) distributions of NOM in the tested surface raw water were concentrated at 3-5 kDa and approximately 0.2 kDa. Regardless of the coagulant species and dosages, the removal of 0.2 kDa NOM molecules was limited. In contrast, NOM at 3-5 kDa were readily removed with increasing coagulant dosages. In particular, aluminum sulfate favorably removed NOM near 5 kDa, whereas ferric chloride tended to reduce 3 kDa organic substances. Although aluminum sulfate and ferric chloride could improve the flux of the ensuing MF treatment, the optimal coagulant dosages to achieve effective pretreatment were different: 2-30 mg/L for aluminum sulfate and >15 mg/L for ferric chloride. The scanning electron microscope (SEM) image of the membrane-filtered coagulated raw water showed that coagulation efficiency dramatically affected membrane flux and that good coagulation properties can reduce membrane fouling.
authors.affiliation: School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, China. yali_song@sina.com.
authors.forename: Yali
authors.initials: Y
authors.lastname: Song
authors.affiliation: College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. dbz77@tongji.edu.cn.
authors.forename: Bingzhi
authors.initials: B
authors.lastname: Dong
authors.affiliation: College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. gaonaiyun@sina.com.
authors.forename: Naiyun
authors.initials: N
authors.lastname: Gao
authors.affiliation: Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, USA. dengy@mail.montclair.edu.
authors.forename: Yang
authors.initials: Y
authors.lastname: Deng
mesh_terms: D000534:Alum Compounds / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D005374:Filtration / Q000379:methods*; D014873:Water Pollutants / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D000534:Alum Compounds; D005290:Ferric Compounds; D014873:Water Pollutants; C041524:aluminum sulfate; C024823:ferric sulfate
keywords: coagulation; membrane flux; membrane fouling; microfiltration; organic matter