School of Chemical Engineering and Analytical Science, and §School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.
Environ Sci Technol. 2014;48(1):558-65. doi: 10.1021/es402953z. Epub 2013 Dec 12.
This work describes the application of a non-thermal plasma generated in a dielectric barrier packed-bed plasma reactor for the remediation of dichloromethane (CH2Cl2, DCM). The overall aim of this investigation is to identify the role of key process parameters and chemical mechanisms on the removal efficiency of DCM in plasma. The influence of process parameters, such as oxygen concentration, concentration of initial volatile organic compounds (VOCs), energy density, plasma residence time, and background gas, on the removal efficiency of 500 ppm DCM was investigated. Results showed a maximum removal efficiency with the addition of 2-4% oxygen into a nitrogen plasma. It is thought that oxygen concentrations in excess of 4% decreased the decomposition of chlorinated VOCs as a result of ozone and nitrogen oxide formation. Increasing the residence time and the energy density resulted in increasing the removal efficiency of chlorinated VOCs in plasma. A chemical kinetic model has been developed on the basis of the proposed reaction scheme, and the calculation of end product concentrations are in general good agreement with the observed values. With the understanding of the effect of the key parameters, it has been possible to optimize the remediation process.
本工作描述了在介质阻挡填充床等离子体反应器中产生的非热等离子体在修复二氯甲烷（CH2Cl2，DCM）中的应用。这项研究的总体目标是确定关键工艺参数和化学机制对等离子体中 DCM 去除效率的影响。研究了工艺参数（如氧气浓度、初始挥发性有机化合物（VOCs）浓度、能量密度、等离子体停留时间和背景气体）对 500ppm DCM 去除效率的影响。结果表明，在氮气等离子体中加入 2-4%的氧气可获得最大的去除效率。据认为，氧气浓度超过 4%会由于臭氧和氮氧化物的形成而降低氯化 VOCs 的分解。增加停留时间和能量密度会导致等离子体中氯化 VOCs 的去除效率增加。在提出的反应方案的基础上建立了化学动力学模型，计算得到的终产物浓度与观察值总体上吻合较好。通过了解关键参数的影响，已经可以优化修复过程。
