title: Effect of SO4 2-/Al3+ ratio and OH-/Al3+ value on the characterization of coagulant poly-aluminum-chloride-sulfate (PACS) and its coagulation performance in water treatment.
abstract: A poly-aluminum-chloride-sulfate (PACS) was prepared at various experimental conditions. It was found that the coagulation performance of PACS in water treatment was affected by the PACS particle size distribution and zeta potential value. The experimental results indicated that the PACS particle size distribution and zeta potential value were highly influenced by SO(4)(2-)/Al(3+) molar ratio and bacicities (gamma,gamma=[OH]/[Al]) value. At a fixed gamma value of 2.0, the average PACS particle size increased from 25 to 80nm with the increase of SO(4)(2-)/Al(3+) ratio from 0 to 0.1. Further increase of the SO(4)(2-)/Al(3+) ratio resulted in acute increment particle size of PACS extremely, which can be attributed to its aggregation. At a fixed SO(4)(2-)/Al(3+) ratio of 0.0664, the largest average size of PACS occurred at gamma=2.0. It was also found that the zeta potential value of PACS was strongly influenced by the SO(4)(2-)/Al(3+) ratio, gamma value and pH of the aquatic solution. The zeta potential value of PACS increased with increasing of SO(4)(2-)/Al(3+) ratio. At a fixed SO(4)(2-)/Al(3+) ratio of 0.0664, PACS achieved greatest zeta potential value at gamma value of around 2.0. The maximum positive zeta potential value of PACS was found at pH5.3. At a fixed gamma value of 2.0 and SO(4)(2-)/Al(3+) ratio of 0.0664, the PACS achieved an optimum natural organic matter and turbidity removal efficiency.
authors.affiliation: School of Environmental Science and Engineering, Shandong University, No. 27 Shanda South Road, Jinan 250100, Shandong, China. bygao@sdu.edu.cn
authors.forename: Baoyu
authors.initials: B
authors.lastname: Gao
authors.forename: Qinyan
authors.initials: Q
authors.lastname: Yue
mesh_terms: D000534:Alum Compounds / Q000737:chemistry; D000535:Aluminum / Q000737:chemistry*; D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D005427:Flocculation; D006878:Hydroxides / Q000737:chemistry; D009391:Nephelometry and Turbidimetry; D010316:Particle Size; D017693:Sodium Bicarbonate / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D018508:Water Purification
chemical_list: D000534:Alum Compounds; D017607:Aluminum Compounds; D002712:Chlorides; D006878:Hydroxides; D013431:Sulfates; C508168:poly-aluminum-chloride-sulfate; C041524:aluminum sulfate; D000077410:Aluminum Chloride; D017693:Sodium Bicarbonate; C031356:hydroxide ion; D000535:Aluminum