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.
J Hazard Mater. 2016 May 5;308:199-207. doi: 10.1016/j.jhazmat.2016.01.049. Epub 2016 Jan 22.
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.
二苯胂酸（DPAA）是一战和二战期间受化学武器污染的环境中的主要污染物，对生物群具有高风险，但针对这种污染物的修复方法却很少。在这里，研究了高压汞灯照射下 DPAA 的光降解。在 UV-C 照射下，DPAA 在 30 分钟内完全降解为无机砷形态。DPAA 的光降解主要取决于其通过激发态 DPAA 的直接光解。相比之下，通过电子顺磁共振（EPR）研究证实了 DPAA 光降解过程中（1）O2 的生成，但（1）O2 对 DPAA 的光降解影响不大。还研究了 DPAA 在土壤浸出液和地下水中的光降解，DPAA 的光解速率受土壤浸出液中总有机碳（TOC）含量和地下水中 NO3（-）浓度的控制。最后，研究了常见溶质对 DPAA 光降解的影响，表明 Cl（-）可以通过延长激发态 DPAA 的寿命来提高 DPAA 的光解速率。此外，NO3（-）、NO2（-）和腐殖酸（HA）可以通过抑制激发态 DPAA 的产生来降低 DPAA 的光解速率。这项研究展示了 DPAA 光降解的详细机制，并为 DPAA 去污提供了一种新的有效方法。
