State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Research Center for Eco-Environmental Sciences (RCEES), Chinese Academy of Sciences, Beijing 100085, China.
Environ Sci Technol. 2020 Apr 7;54(7):4686-4694. doi: 10.1021/acs.est.0c00284. Epub 2020 Mar 16.
Activation of persulfates to degrade refractory organic pollutants is currently a hot topic of advanced oxidation. Developing simple and effective activation approaches is crucial for the practical application of persulfates. We report in this research that trace cupric species (Cu(II) in several μM) can efficiently trigger peroxymonosulfate (PMS) oxidation of various organic pollutants under slightly alkaline conditions. The intermediate oxidant dominating this process was investigated with electron paramagnetic resonance (EPR), chemical probing, and in situ Raman spectroscopy. Unlike conventional PMS activation, which generates sulfate radical, hydroxyl radical, or singlet oxygen as major oxidants, Cu(III) was confirmed to be the primary and selective intermediate oxidant during the Cu(II)/PMS oxidation. Hydroxyl radical is the secondary intermediate oxidant formed from the reaction of Cu(III) with OH. Hybrid oxidation by the two oxidants imparts Cu(II)/PMS with high efficiency in the degradation of a series of pollutants. The results of this work suggest that, with no need of introducing complex catalysts, trace Cu(II) inherent in or artificially introduced to some water or wastewater can effectively trigger PMS oxidation of organic pollutants.
过硫酸盐活化降解难降解有机污染物是目前高级氧化领域的一个热点。开发简单有效的活化方法对于过硫酸盐的实际应用至关重要。本研究报道，在弱碱性条件下，痕量铜物种（几 μM 的 Cu(II)）可以有效地引发过一硫酸盐（PMS）氧化各种有机污染物。通过电子顺磁共振（EPR）、化学探针和原位拉曼光谱研究了该过程中的中间氧化剂。与传统的 PMS 活化生成硫酸根自由基、羟基自由基或单线态氧等主要氧化剂不同，Cu(III)被确认为 Cu(II)/PMS 氧化过程中的主要和选择性中间氧化剂。羟基自由基是 Cu(III)与 OH 反应生成的二次中间氧化剂。两种氧化剂的混合氧化使 Cu(II)/PMS 能够高效降解一系列污染物。本研究结果表明，无需引入复杂的催化剂，水中或废水中固有的或人为引入的痕量 Cu(II)可以有效地引发有机污染物的 PMS 氧化。
