Preparation and characterization of organic polymer modified composite polyaluminum chloride

Article type: Research Article

Authors: SHI, Bao-you | TANG, Hong-xiao

Affiliations: State Key Laboratory of Environmental Aquatic Chemistry, Chinese Academy of Sciences, Beijing 100085, China

Note: [] Corresponding author. E-mail: byshi@rcees.ac.cn

Abstract: Compared with traditional aluminum salts, polyaluminum chloride (PACl) has better coagulation-flocculation performance in turbidity removal. However, it is still inferior to organic polymers in terms of bridging function. In order to improve the aggregating property of PACl, different composite PACl flocculants were prepared with various organic polymers. The effect of organic polymer on the distribution of Al (III) species in composite flocculants was studied using ^{27}Al NMR and Al-ferron complexation methods. The charge neutralization and surface adsorption characteristics of composite flocculants were also investigated. Jar tests were conducted to evaluate the turbidity removal efficacy of organic polymer modified composite flocculants. The study shows that cationic polymer and anionic polymer have significant influences on the coagulation-flocculation behaviors of PACl. Both cationic and anionic polymers can improve the turbidity removal performance of PACl but the mechanisms are much different: cationic organic polymer mainly increases the charge neutralization ability, but anionic polymer mainly enhances the bridging function.

Keywords: polyaluminum chloride (PACl), organic polymer, composite flocculant

Journal: Journal of Environmental Sciences, vol. 18, no. 2, pp. 214-220, 2006