Fabrication of AQ2S/GR composite photosensitizer for the simulated solar light-driven degradation of sulfapyridine

Shuang-Yang Zhao; Cheng-Xin Chen; Jie Ding; Shan-Shan Yang; Ya-Ni Zang; Xu-Dong Qin; Xin-Lei Gao; Zhao Song; Nan-Qi Ren

doi:10.1016/j.ese.2021.100111

Fabrication of AQ2S/GR composite photosensitizer for the simulated solar light-driven degradation of sulfapyridine

Environ Sci Ecotechnol. 2021 Jul 29:8:100111. doi: 10.1016/j.ese.2021.100111. eCollection 2021 Oct.

Authors

Shuang-Yang Zhao¹, Cheng-Xin Chen¹, Jie Ding¹, Shan-Shan Yang¹, Ya-Ni Zang¹, Xu-Dong Qin^{2

3}, Xin-Lei Gao^{2

3}, Zhao Song⁴, Nan-Qi Ren¹

Affiliations

¹ State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
² Harbin Institute of Technology National Engineering Research Center of Water Resources Co.,Ltd, Harbin, 150090, China.
³ Guangdong Yuehai Water Investment Co., Ltd, Shenzhen, 518021, China.
⁴ UNSW Water Research Center, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2032, Australia.

Abstract

Chlorination has been intensively investigated for use in water disinfection and pollutant elimination due to its efficacy and convenience; however, the generation and transportation of chlorine and hypochlorite are energy-consuming and complicated. In this study, a novel binary photosensitizer consisting of anthraquinone-2-sulfonate (AQ2S) and graphene was synthesized via a π-π stack adsorption method; this compound could allow for the chlorination of organic pollutants using on-site chlorine generation. In this photosensitive degradation process, sulfapyridine (SPY) was selected as a model pollutant and was decomposed by the reactive species (Cl₂ ^•-, Cl^• and O₂ ^•-) generated during the photosensitive oxidation of chloride. The synthesized AQ2S/graphene exhibited superior activity, and the degradation rate of SPY was over 90 % after 12 h of visible light irradiation with a kinetic constant of 0.2034h^-1. Results show that 20 mg AQ2S/GR at a 21 % weight percentage of AQ2S in a pH 7 SPY solution with 1 mol/L Cl^- achieved the highest kinetics rate at 0.353 h^-1. Free radical trapping experiments demonstrated that Cl₂ ^•- and O₂ ^•- were the dominant species involved in SPY decomposition under solar light. The reusability and stability of this composite were verified by conducting a cycle experiment over five successive runs. The capacity of photodegradation still remained over 90 % after these 5 runs. The current study provides an energy-efficient and simple-operational approach for water phase SPY control.

Keywords: AQ2S; Free radicals trapping; Photosensitizer; Reusability; Visible-light-driven.