Photosensitized Transformation of Hydrogen Peroxide in Dissolved Organic Matter Solutions under Simulated Solar Irradiation.
Photosensitized Transformation of Hydrogen Peroxide in Dissolved Organic Matter Solutions under Simulated Solar Irradiation.
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DOI：
10.1021/acs.est.2c04819
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发表时间：
2022-09
影响因子：
11.4
通讯作者：
Haitao Sha;Shuwen Yan;Yang Deng;Weihua Song
中科院分区：
文献类型：
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作者：
Haitao Sha;Shuwen Yan;Yang Deng;Weihua Song
过氧化氢在水环境中的光化学过程中起着重要的作用。然而，它是否能被光激发发色溶解有机物(CDOM)转化尚不清楚。因此，本研究考察了模拟日照条件下CDOM富集液中H_2O_2的光敏化降解。我们的结果表明，CDOM的存在通过光敏化过程提高了H_2O_2的光降解速率，并且·OH是随着H_2O_2的衰减而化学计量地产生的。与模型光敏剂的实验结果表明，CDOM的单电子还原物种(CDOM·-)而不是三重态CDOM是还原H_2O_2生成·OH的主要反应物种。通过监测CDOM·-的变化，估算出CDOM·-与H_2O_2的反应速率常数是与O_2的反应速率常数的1.5倍。此外，在模拟的太阳光照射下，废水中加入了过氧化氢，结果表明，随着·OH水平的增加，废水中痕量有机污染物(TROCS)的光降解能力显著增强。总之，本研究为CDOM·-通过单电子还原H_2O_2光化学生成·OH提供了新的见解。利用太阳能辐射强化H_2O_2处理废水是一种经济实用的高级氧化技术。
Hydrogen peroxide plays an important role in photochemical processes in aquatic environments. However, whether it can be transformed by photoexcited chromophoric dissolved organic matter (CDOM) remains unclear. Therefore, this study examined the photosensitized degradation of H2O2 in CDOM-enriched solutions under simulated solar irradiation. Our results suggest that the presence of CDOM enhances the photodegradation rate of H2O2 via the photosensitization process and ·OH is generated stoichiometrically with H2O2 attenuation. Experimental results with model photosensitizers indicate that one-electron reducing species of CDOM (CDOM·-), not triplet CDOM, is the primary reactive species that reduces H2O2 to yield ·OH. By monitoring the variation of CDOM·-, the reaction rate constant of CDOM·- with H2O2 was estimated to be 1.5-fold greater than that with O2. Furthermore, a wastewater effluent was exposed to simulated solar irradiation with the addition of H2O2, and the results demonstrated that the photodegradation of trace organic contaminants (TrOCs) was significantly enhanced by the increased ·OH level. Overall, the current study provided new insights into the photochemical formation of ·OH via the one-electron reduction of H2O2 by CDOM·-. The solar irradiation of wastewater with H2O2 enhancement could be a useful and economically beneficial advanced oxidation process for TrOC abatement.