Vitamin B2-Initiated Hydroxyl Radical Generation under Visible Light in the Presence of Dissolved Iron
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- 作者：Fang Xu ; Xiang-Ning Song ; Guo-Ping Sheng ; Hong-Wei Luo ; Wen-Wei Li ; Ri-Sheng Yao ; Han-Qing Yu
- 刊名：ACS Sustainable Chemistry & Engineering
- 出版年：2015
- 出版时间：August 3, 2015
- 年：2015
- 卷：3
- 期：8
- 页码：1756-1763
- 全文大小：548K
- ISSN：2168-0485
文摘
The generation of hydroxyl radical (鈥?/sup>OH) under solar irradiation from natural photosensitizers is widely recognized to play a key role in the photochemical degradation of biorefractory organic pollutants. Solar-light-mediated 鈥?/sup>OH production has been supposed as a green and sustainable strategy in water and wastewater treatment. In this study, an efficient visible-light-mediated 鈥?/sup>OH generation method using the photosensitization of vitamin B2 (VB2) catalyzed by dissolved iron was proposed. 鈥?/sup>OH generation was validated by electron paramagnetic resonance spectroscopy combined with spin trapping, and was further confirmed using the hydroxylation of nitrobenzene. VB2 plays a dual role of in the process of 鈥?/sup>OH generation. In the initial step, VB2 works as an excellent photosensitizer. Upon absorption of a photon, VB2 gives rise to its excited singlet state (1VB*) and, through intersystem crossing, to its excited triplet state (3VB*). In the subsequent step, VB2 works as an effective electron mediator to mediate O2鈥⑩€?/sup> generation. However, O2鈥⑩€?/sup> is sensitive to proton and is converted to H2O2 quickly in water. Ultimately, the 鈥?/sup>OH generation occurs through dissolved-iron catalyzed decomposition of H2O2. All ingredients involved in this process are nontoxic, environmentally benign, and easily available. Thus, this process might have potential environmental implications.
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