Insight into the transformation of 4-hydroxy-3-aminophenylarsonic acid (HAPA) and its mechanisms under simulated sunlight irradiation

Yixin Zhang; Yingjie Yan; Wenjing Bai; Rui Tang; Kuizu Su; Zhen-Hu Hu

doi:10.1016/j.jhazmat.2023.132925

Insight into the transformation of 4-hydroxy-3-aminophenylarsonic acid (HAPA) and its mechanisms under simulated sunlight irradiation

J Hazard Mater. 2024 Feb 5:463:132925. doi: 10.1016/j.jhazmat.2023.132925. Epub 2023 Nov 4.

Authors

Yixin Zhang¹, Yingjie Yan¹, Wenjing Bai², Rui Tang³, Kuizu Su¹, Zhen-Hu Hu⁴

Affiliations

¹ Anhui Engineering Laboratory of Rural Water Environment and Resource, School of Civil Engineering, Hefei University of Technology, Hefei 230009, PR China.
² Anhui Engineering Laboratory of Rural Water Environment and Resource, School of Civil Engineering, Hefei University of Technology, Hefei 230009, PR China. Electronic address: bwj@mail.hfut.edu.cn.
³ Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai University of Electric Power, Shanghai 200090, PR China.
⁴ Anhui Engineering Laboratory of Rural Water Environment and Resource, School of Civil Engineering, Hefei University of Technology, Hefei 230009, PR China. Electronic address: zhhu@hfut.edu.cn.

PMID: 37951170
DOI: 10.1016/j.jhazmat.2023.132925

Abstract

Four-hydroxy-3-aminophenylarsonic acid (HAPA), the reduced product of roxarsone (4-hydroxy-3-nitro-phenylarsonic acid, ROX) under anaerobic conditions, is resistant to be biologically degraded under anaerobic/anoxic conditions. The transformation of HAPA in aquatic environment under sunlight irradiation is still unknown. In this study, the photodegradation of HAPA and the possible mechanism under simulated sunlight conditions were investigated. The result shows that under visible light irradiation, HAPA wasn't degraded. Under UV₂₅₄ and UV₃₀₂ irradiation, about 60% and 30% HAPA were decomposed, while nearly no HAPA was degraded under UV₃₆₅ irradiation over a period of 240 min. UVC light was the main wavelength for the degradation of HAPA under sunlight conditions. HCO₃^- and NO₃^- slightly enhanced the photodegradation, but Cl^- and SO₄^2- had a marginal influence on the photodegradation. During the photodegradation, HAPA was decomposed into organic intermediates, inorganic arsenics, ammonia and undetermined arsenic species. Arsenite (As(III)) was the dominant inorganic arsenic species from the photodegradation of HAPA. The mechanism analysis shows that singlet molecular oxygen (¹O₂) has little influence on the decomposition of HAPA under UV irradiation, but significantly enhanced the conversion of As(III) to arsenate (As(V)).

Keywords: 4-hydroxy-3-aminophenylarsonic acid (HAPA); Arsenate (As(V)); Arsenite (As(III)); Photodegradation; UV irradiation.