Zhou Shiqing, Bu Lingjun, Yu Yanghai, Zou Xu, Zhang Yansen
Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan, 410082, PR China.
Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan, 410082, PR China.
Chemosphere. 2016 Dec;165:381-387. doi: 10.1016/j.chemosphere.2016.09.057. Epub 2016 Sep 30.
This study investigated the electrochemical degradation of microcystin-LR (MC-LR) using boron-doped diamond (BDD) anode and mixed metal oxides (MMO, IrOTaO/Ti) anode in different medium. In-situ electrogenerated oxidants including hydroxyl radical, active chlorine, and persulfate were confirmed in phosphate, chloride, and sulfate medium, respectively. Different from MMO anode, hydroxyl radical was observed to play a significant role in chlorine generation at BDD anode in chloride medium. Besides, BDD anode could activate sulfate electrochemically due to its high oxygen evolution potential, and MC-LR degradation rate increased with the decrease of solution pH. The effects of natural organic matters (NOM) and algal organic matters (AOM) on MC-LR degradation were evaluated and NOM presented stronger inhibition ability than AOM. Furthermore, the intermediates generated in MC-LR degradation in chloride and sulfate medium were identified by LC/MS/MS and possible degradation pathways were proposed based on the experiments results. Benzene ring and conjugated diene bonds of Adda group and double bonds of Mhda group were found to be the reactive sites of MC-LR. Overall, this study broadens the knowledge of electrochemical oxidation in removing microcystins in algae-laden water.
本研究考察了在不同介质中使用硼掺杂金刚石（BDD）阳极和混合金属氧化物（MMO，IrOTaO/Ti）阳极对微囊藻毒素-LR（MC-LR）进行电化学降解的情况。分别在磷酸盐、氯化物和硫酸盐介质中证实了原位电生成的氧化剂，包括羟基自由基、活性氯和过硫酸盐。与MMO阳极不同，在氯化物介质中，观察到羟基自由基在BDD阳极产生氯的过程中起重要作用。此外，BDD阳极因其高析氧电位能够电化学活化硫酸盐，且MC-LR降解速率随溶液pH值的降低而增加。评估了天然有机物（NOM）和藻类有机物（AOM）对MC-LR降解的影响，发现NOM的抑制能力比AOM更强。此外，通过LC/MS/MS鉴定了氯化物和硫酸盐介质中MC-LR降解产生的中间体，并根据实验结果提出了可能的降解途径。发现Adda基团的苯环和共轭二烯键以及Mhda基团的双键是MC-LR的反应位点。总体而言，本研究拓宽了电化学氧化去除富藻水中微囊藻毒素方面的知识。
