TY - JOUR

T1 - EDTA enhances the photodegradation of p-arsanilic acid in the presence of iron at near-neutral pH

AU - Zhao, Chuxuan

AU - Liu, Zixin

AU - Wu, Yi

AU - Guo, Juntao

AU - Huang, Peng

AU - Wang, Yifei

AU - Leng, Yeheng

AU - Pozdnyakov, Ivan P.

AU - Xu, Jing

AU - Wu, Feng

N1 - Funding Information: This work was supported by National Natural Science Foundation of China (No. 21707106 , 42077350, 22061132001), Russian Science Foundation (Grant RSF-NSFC No. 21-43-00004), and China Postdoctoral Science Foundation (2016M602358). Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022/12/15

Y1 - 2022/12/15

N2 - The widespread used organic arsenic pesticides and veterinary drugs have drawn attention for decades. Its photochemical transformation in the surface water contributes to its degradation and the formation of products. The effect of co-existent components like anthropogenic reagents (e.g. ethylenediaminetetraacetatic acid, EDTA) on the photochemical transformation has still to be investigated in depth. Fe(III)-EDTA complex is a common and abundant complex in surface water. In this work, UVA light and simulated sunlight have been used as light sources to explore the effect of Fe(III)-EDTA on the photodegradation of p-arsanilic acid (ASA), used as an organic arsenic feed additive. Whereas ASA hardly absorbs UVA light and can only be directly photolyzed by simulated sunlight, the Fe(III)-EDTA complex is photoactive under either light source. At pH 6, the presence of Fe(III)-EDTA complex enhances the photodegradation efficiency of ASA from 0% to ca. 23% after 180 min reaction under UVA light irradiation, and from 30% to ca. 58% after 45 min reaction under simulated sunlight irradiation. Appropriate amount of EDTA enhances the photodegradation efficiency, whereas excessive EDTA suppresses the initial reaction rate. Mechanistic study has revealed contributions from direct photolysis and photochemical reactions of Fe(III)-EDTA and Fe(III)–OH complexes. Generated •OH has been confirmed as the important contribution. Photodegradation products include inorganic arsenic, organic arsenic, and other organic by-products, and the proportions of these products vary in different light-induced systems due to the diverse reaction pathways. The results of this work improve our understanding of the risks of residual ASA in the environment, allow prediction of its migration and transformation, and show how organic arsenic livestock and poultry feed additives might be removed.

AB - The widespread used organic arsenic pesticides and veterinary drugs have drawn attention for decades. Its photochemical transformation in the surface water contributes to its degradation and the formation of products. The effect of co-existent components like anthropogenic reagents (e.g. ethylenediaminetetraacetatic acid, EDTA) on the photochemical transformation has still to be investigated in depth. Fe(III)-EDTA complex is a common and abundant complex in surface water. In this work, UVA light and simulated sunlight have been used as light sources to explore the effect of Fe(III)-EDTA on the photodegradation of p-arsanilic acid (ASA), used as an organic arsenic feed additive. Whereas ASA hardly absorbs UVA light and can only be directly photolyzed by simulated sunlight, the Fe(III)-EDTA complex is photoactive under either light source. At pH 6, the presence of Fe(III)-EDTA complex enhances the photodegradation efficiency of ASA from 0% to ca. 23% after 180 min reaction under UVA light irradiation, and from 30% to ca. 58% after 45 min reaction under simulated sunlight irradiation. Appropriate amount of EDTA enhances the photodegradation efficiency, whereas excessive EDTA suppresses the initial reaction rate. Mechanistic study has revealed contributions from direct photolysis and photochemical reactions of Fe(III)-EDTA and Fe(III)–OH complexes. Generated •OH has been confirmed as the important contribution. Photodegradation products include inorganic arsenic, organic arsenic, and other organic by-products, and the proportions of these products vary in different light-induced systems due to the diverse reaction pathways. The results of this work improve our understanding of the risks of residual ASA in the environment, allow prediction of its migration and transformation, and show how organic arsenic livestock and poultry feed additives might be removed.

KW - Fe(III)-EDTA complex

KW - P-arsanilic acid

KW - Photodegradation

KW - Photoproducts

KW - •OH

UR - http://www.scopus.com/inward/record.url?scp=85134597226&partnerID=8YFLogxK

U2 - 10.1016/j.cej.2022.137984

DO - 10.1016/j.cej.2022.137984

M3 - Article

AN - SCOPUS:85134597226

VL - 450

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

SN - 1385-8947

M1 - 137984

ER -