Coagulation performance and floc characteristics of aluminum sulfate with cationic polyamidine as coagulant aid for kaolin-humic acid treatment

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 481; pp. 476 - 484
• Main Authors: Guo, Bo, Yu, Huan, Gao, Baoyu, Rong, Hongyan, Dong, Hongyu, Ma, Defang, Li, Ruihua, Zhao, Shuang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.09.2015
• Subjects: Aluminum sulfate; Coagulation performance; Floc properties; Polyamidine; Coagulation performance; Polyamidine; Aluminum sulfate; Floc properties
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2015.06.017

[Display omitted] •The synthesize method of polyamidine was investigated and optimized.•Coagulation performance of AS-polyamidine and AS was comparatively evaluated.•The characteristics of flocs generated by the two kinds of coagulants were studied.•The size and growth rate of the flocs were enhanced by the aid effect of polyamidine.•Recovery ability of flocs was improved due to the assistant role of polyamidine. In this study, novel cationic polyamidine (Pa) was synthesized and used as coagulant aid with aluminum sulfate (AS) for kaolin-humic acid simulated water treatment. The effects of Pa on coagulation performance and floc properties were investigated. Results showed that Pa addition significantly enhanced the removal of turbidity, ultraviolet absorbance at 254nm wavelength (UV254) and dissolved organic carbon (DOC). AS–Pa exhibited high coagulation efficiency at border pH range and increased floc size and growth rate significantly. Floc recovery ability was also improved, while floc fractal dimension was lower with Pa addition. This would be attributed to high cationic charge density and long chain of Pa, which could enhance the effect of charge neutralization and adsorption bridging.