Simultaneous removal of harmful algal cells and toxins by a Ag2CO3-N:GO photocatalyst coating under visible light

Gongduan Fan; Zhong Chen; Liang Hong; Banghao Du; Zhongsen Yan; Jiajun Zhan; Yifan You; Rongsheng Ning; Heshun Xiao

doi:10.1016/j.scitotenv.2020.140341

Simultaneous removal of harmful algal cells and toxins by a Ag₂CO₃-N:GO photocatalyst coating under visible light

Sci Total Environ. 2020 Nov 1:741:140341. doi: 10.1016/j.scitotenv.2020.140341. Epub 2020 Jun 23.

Authors

Gongduan Fan¹, Zhong Chen², Liang Hong², Banghao Du², Zhongsen Yan³, Jiajun Zhan², Yifan You², Rongsheng Ning², Heshun Xiao⁴

Affiliations

¹ College of Civil Engineering, Fuzhou University, 350116, Fujian, China; State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, 350002, Fujian, China; Fujian Provincial Key Laboratory of Electrochemical Energy Storage Materials, Fuzhou University, 350002, Fujian, China. Electronic address: fgdfz@fzu.edu.cn.
² College of Civil Engineering, Fuzhou University, 350116, Fujian, China.
³ College of Civil Engineering, Fuzhou University, 350116, Fujian, China; State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, 350002, Fujian, China.
⁴ China Construction Third Bureau First Engineering Co. Ltd., 430040, Hubei, China.

PMID: 32615428
DOI: 10.1016/j.scitotenv.2020.140341

Abstract

The frequent harmful algae blooms (HABs) in eutrophic waters pose serious threats to the water environment and health of human beings and animals. In this study, a new type of photocatalytic coating was prepared by loading Ag₂CO₃-N:GO (AGON) on the polyurethane sponge modified by silica sol via a dip coating method for the photocatalytic inactivation of Microcystis aeruginosa (M. aeruginosa) and degradation of Microcystin-LR (MC-LR). The factors including photocatalyst loading dosage, natural organic matter (NOM), and alkalinity were studied. The effects on the physiological characteristics of M. aeruginosa and reactive oxygen species (ROS) were also investigated to reveal the photocatalytic inactivation mechanisms. The results showed that the AGON coating-4 (the initial concentration of AGON suspension used for loading is 4 g/L) exhibited the optimum photocatalytic performance under visible light, which can completely remove chlorophyll a after 5 h of irradiation. And the NOM and alkalinity in water have relatively negative effects on the photocatalytic inactivation of algae. The prepared AGON coating also exhibited excellent photocatalytic performance in the degradation of MC-LR under visible light. It only needed 20, 60 and 120 min to completely degrade 0.1, 0.3 and 0.5 mg/L MC-LR, respectively. However, the mixed systems of algae and MC-LR required a longer time to achieve photocatalytic degradation. The O₂^- were the predominant reactive oxygen species, causing the damage of cell membranes and walls and the leakage of cellular content, which eventually led to the irreversible damage to algal cells. What's more, the coating can be reused several times due to its good cyclability and stability. Therefore, the AGON coating has promising prospects for the treatment of algal blooms in eutrophic waters.

Keywords: Ag(2)CO(3)-N:GO; Coating; Microcystis aeruginosa; Microcystis-LR; Photocatalyst.

MeSH terms

Animals
Chlorophyll A
Harmful Algal Bloom
Light
Microcystins
Microcystis*
Silver*

Substances

Microcystins
Silver
Chlorophyll A