Li Wenshu, Zhou Peng, Zhang Jing, Zhang Yongli, Zhang Gucheng, Liu Yang, Cheng Xin
College of Architecture & Environment, Sichuan University, Chengdu 610065, China E-mail:
Water Sci Technol. 2018 Nov;78(5-6):1390-1399. doi: 10.2166/wst.2018.416.
This study investigated the generation of reactive oxygen species (ROS) (O •, HO, and HO•) by promoting the Cu(II)/Cu(I) redox cycle with certain reducing agents (RAs) in aerobic aqueous solution, and benzoic acid (BA) was employed as indicator for the hydroxyl radical (HO•). Hydroxylamine (HA) can reduce Cu(II) to Cu(I) to induce chain reactions of copper species resulting in the generation of the superoxide radical (O •) and hydrogen peroxide (HO), and the intermediate Cu(I) can further activate HO via a Fenton-like reaction to produce HO•, creating the remarkable BA degradation. O is indispensable, and unprotonated HA is the motive power in the O/Cu/HA system. Moreover, pH is a crucial factor of the O/Cu/HA system due to the protonated HA not being able to reduce Cu(II) into Cu(I). The oxidation of HA can be effectively induced by trace amounts of Cu(II), and both a higher HA dosage and a higher Cu(II) dosage can enhance HO generation and BA degradation. In addition, some other RAs that can reduce Cu(II) into Cu(I) could replace HA in the O/Cu/HA system to induce the generation of these ROS in aerobic aqueous solution.
本研究探讨了在有氧水溶液中，通过某些还原剂（RAs）促进铜（II）/铜（I）氧化还原循环产生活性氧（ROS）（超氧阴离子自由基（O•）、过氧化氢（HO）和羟基自由基（HO•））的情况，并使用苯甲酸（BA）作为羟基自由基（HO•）的指示剂。羟胺（HA）能将铜（II）还原为铜（I），引发铜物种的链式反应，导致超氧阴离子自由基（O•）和过氧化氢（HO）的生成，中间产物铜（I）可通过类芬顿反应进一步活化过氧化氢生成羟基自由基（HO•），从而实现显著的BA降解。超氧阴离子自由基（O•）不可或缺，未质子化的HA是O/Cu/HA体系中的驱动力。此外，pH是O/Cu/HA体系的关键因素，因为质子化的HA无法将铜（II）还原为铜（I）。痕量铜（II）能有效诱导HA的氧化，较高的HA用量和较高的铜（II）用量均可增强羟基自由基（HO•）的生成及BA的降解。此外，一些其他能将铜（II）还原为铜（I）的还原剂可在O/Cu/HA体系中替代HA，以在有氧水溶液中诱导这些ROS的生成。
