Synergistic Photogeneration of Reactive Oxygen Species by Dissolved Organic Matter and C60 in Aqueous Phase

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• 作者：Yang Li ; Junfeng Niu ; Enxiang Shang ; John Charles Crittenden
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：January 20, 2015
• 年：2015
• 卷：49
• 期：2
• 页码：965-973
• 全文大小：519K
• ISSN：1520-5851

文摘

We investigated the photogeneration of reactive oxygen species (ROS) by C₆₀ under UV irradiation, when humic acid (HA) or fulvic acid (FA) is present. When C₆₀ and dissolved organic matter (DOM) were present as a mixture, singlet oxygen (¹O₂) generation concentrations were 1.2鈥?.5 times higher than the sum of ¹O₂ concentrations that were produced when C₆₀ and DOM were present in water by themselves. When C₆₀ and HA were present as a mixture, superoxide radicals (O₂^{鈥⑩€?/sup>) were 2.2鈥?.6 times more than when C₆₀ and HA were present in water by themselves. A synergistic ROS photogeneration mechanism involved in energy and electron transfer between DOM and C₆₀ was proposed. Enhanced 1O₂ generation in the mixtures was partly due to 3DOM* energy transfer to O₂. However, it was mostly due to 3DOM* energy transfer to C₆₀ producing 3C₆₀*. 3C₆₀* has a prolonged lifetime (>4 渭s) in the mixture and provides sufficient time for energy transfer to O₂, which produces 1O₂. The enhanced O₂鈥⑩€?/sup> generation for HA/C₆₀ mixture was because 3C₆₀* mediated electron transfer from photoionized HA to O₂. This study demonstrates the importance of considering DOM when investigating ROS production by C₆₀.}