Removal of polystyrene and polyethylene microplastics using PAC and FeCl3 coagulation: Performance and mechanism

Guanyu Zhou; Qingguo Wang; Jia Li; Qiansong Li; Hao Xu; Qian Ye; Yunqi Wang; Shihu Shu; Jing Zhang

doi:10.1016/j.scitotenv.2020.141837

Removal of polystyrene and polyethylene microplastics using PAC and FeCl₃ coagulation: Performance and mechanism

Sci Total Environ. 2021 Jan 15:752:141837. doi: 10.1016/j.scitotenv.2020.141837. Epub 2020 Aug 20.

Authors

Guanyu Zhou¹, Qingguo Wang¹, Jia Li², Qiansong Li¹, Hao Xu¹, Qian Ye¹, Yunqi Wang¹, Shihu Shu³, Jing Zhang⁴

Affiliations

¹ College of Architecture & Environment, Sichuan University, Chengdu 610065, China.
² State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
³ School of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
⁴ College of Architecture & Environment, Sichuan University, Chengdu 610065, China; State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China. Electronic address: zjing428@163.com.

PMID: 32889273
DOI: 10.1016/j.scitotenv.2020.141837

Abstract

As a new type of potentially threatening pollutant, microplastics are widely distributed in water and may come into contact with the humans through tap water. The removal behaviors of microplastics in water treatment plants coagulation are not completely clear. In this paper, the removal performance and mechanism of polystyrene (PS) and polyethylene (PE) microplastics using PAC and FeCl₃ coagulation were studied. Results showed that PAC was better than FeCl₃ in removal efficiency of PS and PE microplastics. Charge neutralization occurred in the coagulation process. The figures of scanning electron microscope (SEM) illustrate that agglomeration adsorption occurred in PS system, and the Fourier transform infrared spectroscope (FTIR) spectra demonstrates that new bonds were formed during the interaction between PS microplastics and coagulants. In addition, the hydrolysis products of coagulants played a major role rather than the hydrolysis process in both PS system and PE system. The removal efficiency of microplastics in alkaline conditions was higher than that in acidic conditions. Cl^- had little effect on the removal efficiency of microplastics, while SO₄^2- and CO₃^2- had inhibitory and promoting effects respectively. The increase of stirring speed could improve the removal efficiency of microplastics. This paper can provide a reference for the study of microplastics treated by coagulation.

Keywords: Coagulation; Mechanism; Microplastics; Removal performance.