Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China; Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.
Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China; Department of Modern Mechanics and School of Life Science, University of Science & Technology of China, Hefei, China.
Chemosphere. 2018 Aug;204:351-358. doi: 10.1016/j.chemosphere.2018.04.052. Epub 2018 Apr 11.
Chlorinated phenols are a class of contaminants found in water and have been regarded as a great potential risk to environment and human health. It is thus urgent to develop effective techniques to remove chlorinated phenols in wastewater. For this purpose, we employed dielectric barrier discharge (DBD) in this work and studied the efficiency of DBD for the degradation of 2,4-dichlorophenol (2,4-DCP), one of the most typical chlorophenols in the environment. The effects of pH value, applied voltage and plasma-working gases on the dichlorophenol-removal efficiency were investigated. The results demonstrate that DBD plasma could successfully degrade 2,4-DCP, achieving efficiency of 98.16% (k = 1.09 min) in the Ar-DBD system, and 77.60% (k = 0.48 min) in the N-DBD system, with the process following the first-order kinetics. The removal efficiency was reduced in the presence of radical scavengers, confirming that hydroxyl radicals played a key role in the degradation process, while other active substances were also found such as nitrogen radicals in the N-DBD system, which was found to have also contribution to the degradation of 2,4-DCP. The intermediates and final products generated in the degradation process were analyzed using gas chromatography-mass spectrometry (GC-MS). Based on the identification of intermediates, the degradation pathways and mechanism were proposed and discussed. Besides, the toxicity of the DBD treated 2,4-DCP solution was also assessed using GFP-expressing recombinant Escherichia coli (E. coli) as the testing organism, showing that plasma treatment could substantially reduce the toxic effect of 2,4-DCP.
氯酚类化合物是水中的一类污染物，已被认为对环境和人类健康具有巨大的潜在风险。因此，开发有效去除废水中氯酚类化合物的技术迫在眉睫。为此，我们在这项工作中采用了介质阻挡放电（DBD），并研究了 DBD 对 2,4-二氯苯酚（2,4-DCP）降解的效率，2,4-DCP 是环境中最典型的氯酚类化合物之一。考察了 pH 值、外加电压和等离子体工作气体对二氯酚去除效率的影响。结果表明，DBD 等离子体可以成功降解 2,4-DCP，在 Ar-DBD 体系中去除效率达到 98.16%（k=1.09 min），在 N-DBD 体系中去除效率达到 77.60%（k=0.48 min），过程符合一级动力学。在自由基清除剂存在的情况下，去除效率降低，证实了羟基自由基在降解过程中起着关键作用，而在 N-DBD 体系中还发现了其他活性物质，如氮自由基，它们也有助于 2,4-DCP 的降解。使用气相色谱-质谱联用仪（GC-MS）分析了降解过程中生成的中间体和最终产物。基于中间体的鉴定，提出并讨论了降解途径和机制。此外，还使用表达 GFP 的重组大肠杆菌（E. coli）作为测试生物评估了 DBD 处理 2,4-DCP 溶液的毒性，结果表明等离子体处理可以显著降低 2,4-DCP 的毒性。
