Rapid and efficient removal of heavy metal and cationic dye by carboxylate-rich magnetic chitosan flocculants: Role of ionic groups

Bingzhi Liu; Xin Chen; Huaili Zheng; Yili Wang; Yongjun Sun; Chuanliang Zhao; Shixin Zhang

doi:10.1016/j.carbpol.2017.10.089

Rapid and efficient removal of heavy metal and cationic dye by carboxylate-rich magnetic chitosan flocculants: Role of ionic groups

Carbohydr Polym. 2018 Feb 1:181:327-336. doi: 10.1016/j.carbpol.2017.10.089. Epub 2017 Oct 26.

Authors

Bingzhi Liu¹, Xin Chen¹, Huaili Zheng², Yili Wang³, Yongjun Sun⁴, Chuanliang Zhao¹, Shixin Zhang¹

Affiliations

¹ Key laboratory of the Three Gorges Reservoir Region's Eco-Environment, State Ministry of Education, Chongqing University, Chongqing, 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing, 400045, China.
² Key laboratory of the Three Gorges Reservoir Region's Eco-Environment, State Ministry of Education, Chongqing University, Chongqing, 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing, 400045, China. Electronic address: hlz6512@163.com.
³ College of Environmental Science and Engineering, Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China.
⁴ Jiangsu Key Laboratory of Industrial Water-Conservation & Emission Reduction, College of Environment, Nanjing Tech University, Nanjing, 211800, China.

PMID: 29253979
DOI: 10.1016/j.carbpol.2017.10.089

Abstract

A multifunctional carboxylate-rich magnetic chitosan flocculant (Mag@PIA-g-CS) was prepared through surface graft copolymerization on magnetite particles. The effect of monomer molar ratio, initiator and pre-neutralized degree on polymerization rate was determined. Various analytical methods were applied to characterize Mag@PIA-g-CS, exhibiting the successful grafting of polymers, good magnetic feature and core-shell structure. The kinetic process of Ni(II) and malachite green (MG) flocculation by Mag@PIA-g-CS reached equilibrium within <60min with the optimal uptake rate of 98.3% and 87.4%, and exhibited satisfactory removal effect in wide pH range (4.0-8.0 for Ni(II), 5.0-10.0 for MG). Mag@PIA-g-CS exhibited superior flocculation performance over chitosan magnetic flocculant (Mag@CS). The pH-dependent behavior, rapid responsiveness and sensitivity to ionic strength in batch flocculation tests indicated the distinct effect of ionic groups. Moreover, sweeping action of linear molecular chains facilitated further flocculation. Mag@PIA-g-CS showed high stability in extreme environments, and can be easily regenerated and separated.

Keywords: Adsorption; Ionic groups; Magnetic flocculants; Malachite green; Nickel; Sweep flocculation.