title: Photodegradation of diphenylarsinic acid by UV-C light: Implication for its remediation.
abstract: Diphenylarsinic acid (DPAA) is a major contaminant in environments polluted by chemical weapons and abandoned after World Wars I and II and poses high risks to biota but remediation methods for this contaminant are rare. Here, the photodegradtion of DPAA was studied under high-pressure Hg lamp irradiation. DPAA was degraded completely into inorganic arsenic species in 30 min under UV-C irradiation. The photodegradation of DPAA depended mainly on its direct photolysis through excited-state DPAA. By contrast, the generation of (1)O2 during the photodegradation of DPAA was confirmed by electron paramagnetic resonance (EPR) studies, but (1)O2 had little effect on the photodegradation of DPAA. Phtotodegradation of DPAA was also studied in soil leachates and groundwater and the photolytic rate of DPAA was controlled by the total organic carbon (TOC) content in soil leachates and by the NO3(-) concentration in groundwater. Finally, studies on the effects of common solutes on the photodegradation of DPAA show that Cl(-) can increase the photolytic rate of DPAA by prolonging the lifetime of excited-state DPAA. Moreover, NO3(-), NO2(-), and humic acid (HA) can decrease the photolytic rate of DPAA by suppressing the production of excited-state DPAA. This research shows the detailed mechanism of DPAA photodegradation and provides a new and effective method for DPAA decontamination.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Anan
authors.initials: A
authors.lastname: Wang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Teng
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Hu
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Longhua
authors.initials: L
authors.lastname: Wu
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China. Electronic address: ymluo@yic.ac.cn.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Peter
authors.initials: P
authors.lastname: Christie
keywords: Diphenylarsinic acid; Electron paramagnetic resonance; Photodegradation; Pseudo-first-order kinetics