TY - JOUR

T1 - Kinetics and mechanisms of pH-dependent direct photolysis of p-arsanilic acid under UV-C light

AU - Xu, Jing

AU - Shen, Xiangyi

AU - Wang, Duanli

AU - Zhao, Chuxuan

AU - Liu, Zizheng

AU - Pozdnyakov, Ivan P.

AU - Wu, Feng

AU - Xia, Jun

N1 - Publisher Copyright: © 2017 Elsevier B.V.

PY - 2018/3/15

Y1 - 2018/3/15

N2 - The usage of p-arsanilic acid (ASA) in livestock and poultry farms leads to its release into the environment. The phototransformation of ASA generates toxic inorganic arsenic species and organic by-products, which affects the water security of the peripheral river basin. In this work, we have investigated the pH-dependent kinetics and mechanisms of ASA photolysis under Ultraviolet-C (UV-C) light (254 nm) irradiation in the pH range 1–11 in the absence of oxygen. The degradation rate of ASA, the ratio of the generated inorganic arsenic species, and the amount of primary organic by-products were determined under the aforesaid conditions. Our results clearly showed the pH-dependent photochemistry of ASA. The photolysis rate was low under acidic conditions, and As(III) and p-aminophenol were the main products. With increasing pH, the photolysis rate increased significantly, and As(V) and aniline became the main products. A pH-based kinetic model has been established that allows prediction of the generation rates of As(III), As(V), p-aminophenol, and aniline according to the photolysis rate of ASA.

AB - The usage of p-arsanilic acid (ASA) in livestock and poultry farms leads to its release into the environment. The phototransformation of ASA generates toxic inorganic arsenic species and organic by-products, which affects the water security of the peripheral river basin. In this work, we have investigated the pH-dependent kinetics and mechanisms of ASA photolysis under Ultraviolet-C (UV-C) light (254 nm) irradiation in the pH range 1–11 in the absence of oxygen. The degradation rate of ASA, the ratio of the generated inorganic arsenic species, and the amount of primary organic by-products were determined under the aforesaid conditions. Our results clearly showed the pH-dependent photochemistry of ASA. The photolysis rate was low under acidic conditions, and As(III) and p-aminophenol were the main products. With increasing pH, the photolysis rate increased significantly, and As(V) and aniline became the main products. A pH-based kinetic model has been established that allows prediction of the generation rates of As(III), As(V), p-aminophenol, and aniline according to the photolysis rate of ASA.

KW - Direct photolysis

KW - Kinetic modeling

KW - p-arsanilic acid

KW - pH-Dependent mechanism

UR - http://www.scopus.com/inward/record.url?scp=85037526727&partnerID=8YFLogxK

U2 - 10.1016/j.cej.2017.12.037

DO - 10.1016/j.cej.2017.12.037

M3 - Article

AN - SCOPUS:85037526727

VL - 336

SP - 334

EP - 341

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

SN - 1385-8947

ER -