Characterization and flocculation evaluation of a novel carboxylated chitosan modified flocculant by UV initiated polymerization

Yongjun Sun; Wenquan Sun; Kinjal J Shah; Pen-Chi Chiang; Huaili Zheng

doi:10.1016/j.carbpol.2018.12.064

Characterization and flocculation evaluation of a novel carboxylated chitosan modified flocculant by UV initiated polymerization

Carbohydr Polym. 2019 Mar 15:208:213-220. doi: 10.1016/j.carbpol.2018.12.064. Epub 2018 Dec 21.

Authors

Yongjun Sun¹, Wenquan Sun², Kinjal J Shah³, Pen-Chi Chiang³, Huaili Zheng⁴

Affiliations

¹ College of Urban Construction, Nanjing Tech University, Nanjing, 211800, China. Electronic address: sunyongjun@njtech.edu.cn.
² College of Urban Construction, Nanjing Tech University, Nanjing, 211800, China.
³ Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Road, Taipei City, 10673, Taiwan; Carbon Cycle Research Center, National Taiwan University, 71 Fang-Lan Road, Taipei City, 10674, Taiwan.
⁴ Key laboratory of the Three Gorges Reservoir Region's Eco-Environment, State Ministry of Education, Chongqing University, Chongqing, 400045, China.

PMID: 30658793
DOI: 10.1016/j.carbpol.2018.12.064

Abstract

In this work, carboxylated chitosan modified flocculant (CC-g-PCD) was prepared by graft copolymerization technique to enhance the charge-attracting and adhesion of bridges and net-sweeping capacity of flocculants. The dimethyldiallylammonium chloride (DMDAAC), carboxylated chitosan (CMCS), and 3-chloro-2-chloropropyltrimethylammonium chloride (CTA) were utilized for synthesis of CC-g-PCD via photopolymerization techniques. The synthesized CC-g-PCD was characterized by ¹H NMR, SEM, XRD, and FTIR, and the characteristic groups on the main chain and surface morphological structure of CC-g-PCD were investigated. The obtained results indicated that CTA and DMDAAC were successfully grafted into the CPCTS. In ordered to evaluate the flocculation performance of CC-g-PCD at various dosages, stirring intensity (G value), and pH value by detecting Chl a, COD, and turbidity, the actual lake water that contains algae was used for flocculation assessment tests. The experimental results of the water sample with flocculation showed that the maximum flocculation efficiency of turbidity (91.1%), Chl a (97.2%), and COD (97.0%) can be achieved by CC-g-PCD at pH 7, G value 200 s^-1, and 4.0 mg/L. The comparison results demonstrated that CC-g-PCD had better flocculation efficiency than commercial flocculants. Finally, based on the analysis of algae removal in combination with Zeta potential measurements, the flocculation mechanisms in actual lake water at various dosages and pH values were adsorption bridging and electrical neutralization.

Keywords: Algae removal; Cationic modification; Chitosan; Flocculation; Photopolymerization.