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引用次数: 0
摘要
溶解有机物(DOM)可通过光敏作用影响污染物的转化,但目前的研究大多集中在亲水性污染物上,因此对疏水性污染物的关注较少。本文利用 DOM 标准物质和模型化合物,在异质体系中系统研究了共存 DOM 对黄河悬浮颗粒上十氯联苯(PCB-209)光降解的影响和作用机理。通过分子探针实验、质谱分析和理论计算,我们发现 DOM 的激发三重态(3DOM*)可以激发 PCB-209 发生脱氯反应。由于电子跃迁的模式不同,羰基的存在降低了 3DOM* 的能量,而电子捐献基团则提高了 3DOM* 的能量。含有酚羟基的 DOM 会导致更高的 -OH 稳态浓度,而含有苯基酮结构的 DOM 产生 -O2- 的能力更强。与水基 -OH 相比,疏水性微区产生的 -O2- 更容易与 PCB-209 发生反应。这项研究加深了人们对 DOM 不同官能团在疏水性化合物光敏转化中的作用的认识。
Effect of Dissolved Organic Matter on the Photodegradation of Decachlorobiphenyl (PCB-209) in Heterogeneous Systems: Experimental Analysis and Excited-State Theory Calculations.
Dissolved organic matter (DOM) can affect the transformation of pollutants through photosensitization, but most current research focuses on hydrophilic pollutants, making it such that less attention is paid to hydrophobic pollutants. In this paper, the effect and action mechanism of coexisting DOM on the photodegradation of decachlorobiphenyl (PCB-209) on suspended particles collected from the Yellow River were systematically investigated in a heterogeneous system using DOM standards and model compounds. Through molecular probe experiments, mass spectrometry analysis and theoretical calculations, we found that the excited triplet state of DOM (3DOM*) could excite PCB-209 to undergo dechlorination reaction. Due to the different modes of electron transition, the presence of carbonyl groups decreased the energy of 3DOM*, whereas the electron-donating groups made the energy of 3DOM* higher. DOM containing phenolic hydroxyl groups led to a higher steady-state concentration of •OH, and DOM containing phenyl ketone structures had a stronger ability to produce •O2-. Compared with aqueous •OH, •O2- produced from hydrophobic microregions could react more readily with PCB-209. This study deepens the understanding of the role of different functional groups of DOM in the photosensitized transformation of hydrophobic compounds.
期刊介绍:
Environmental Science & Technology (ES&T) is a co-sponsored academic and technical magazine by the Hubei Provincial Environmental Protection Bureau and the Hubei Provincial Academy of Environmental Sciences.
Environmental Science & Technology (ES&T) holds the status of Chinese core journals, scientific papers source journals of China, Chinese Science Citation Database source journals, and Chinese Academic Journal Comprehensive Evaluation Database source journals. This publication focuses on the academic field of environmental protection, featuring articles related to environmental protection and technical advancements.