title: Floc properties and membrane fouling of polyferric silicate chloride and polyferric chloride: the role of polysilicic acid.
abstract: Impact of polysilicic acid (pSi) in polyferric silicate chloride (PFSiC) on coagulation-ultrafiltration process was investigated in comparison with polyferric chloride (PFC). The Fe(III) species distribution in PFSiC and PFC was measured by a timed complexation spectroscopy method. Characteristics of flocs produced by PFSiC and PFC were studied using a laser diffraction particle sizing device. Moreover, membrane fouling was evaluated using a dead-end batch ultrafiltration unit under two operation modes, coagulation-ultrafiltration (C-UF) and coagulation-sedimentation-ultrafiltration (CSUF). The results indicated that PFSiC with various Si/Fe ratios had better turbidity removal efficiency but inferior organic matter removal. Flocs formed by PFSiC were larger than those by PFC. In case of PFSiC, floc size increased with Si/Fe ratio increasing. PFSiC with various Si/Fe ratios resulted in more compact and weaker flocs than PFC. Ultrafiltration experiments indicated that under C-UF mode, PFSiC with Si/Fe ratios of 0.07 and 0.10 presented better membrane performance than PFC. Under CSUF mode, addition of pSi could alleviate membrane fouling.
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, No. 27 Shanda South Road, Ji' nan, 250100, Shandong, People' s Republic of China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Dong
authors.forename: Baoyu
authors.initials: B
authors.lastname: Gao
authors.forename: Qinyan
authors.initials: Q
authors.lastname: Yue
authors.forename: Shenglei
authors.initials: S
authors.lastname: Sun
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry*; D005427:Flocculation; D008567:Membranes, Artificial; D008962:Models, Theoretical; D010316:Particle Size; D017640:Silicates / Q000737:chemistry*; D012824:Silicic Acid / Q000737:chemistry*; D014462:Ultrafiltration / Q000379:methods; D018508:Water Purification / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D008567:Membranes, Artificial; D017640:Silicates; C541115:polyferric chloride; D012824:Silicic Acid