双管式多段填充床介质阻挡放电（DPDBD）新方法处理苯系物的研究

The emmision of VOCs not only influences human health, but also causes photosmog and haze, which makes the air pullution more and more serious in city. The dielectric barrier discharge (DBD) technique has been considered as an efficient way to treat VOCs. However, the traditional DBD method can hardly mineralize complex structured VOCs, such as benzene compounds. Meanwhile, the traditional DBD may also generate large amount of harmful by-products, such as NOx. In this project, we propose to establish a new double tubed packed bed DBD (DPDBD) method with benzene compounds as simulated pollutants combining the former researched double tubed DBD with catalytic method to enhance mineralization efficiency and decrease the geneartion of by-products. The catalysts will be screened and combined, the degradation performance of the catalyst will be researched, the synergy effect betwwen different catalysts will also be studied and the the influence of experimental conditions on mineralization efficiency will be investigated. Meanwhile, the degradation mechanisms and path ways of the benzene compounds in this new system will also be investigated by detection of products and active groups during the reactions.

VOCs的排放不仅严重威胁着人类健康，其导致的光化学烟雾、城市雾霾等复合大气污染问题亦日趋严重。介质阻挡放电（Dielectric Barrier Discharge，DBD）等离子体技术被认为是一种有效处理VOCs的方法。然而传统的DBD技术很难对较复杂结构的VOCs，如苯系物等实现彻底矿化，同时还会产生有害副产物，如NOx等。本项目针对前期开发的双管式DBD方法副产物生成量较高的问题，拟将其与催化技术相结合，开发一种双管式多段填充床介质阻挡放电（DPDBD）新方法，在保证高矿化效率的同时减少副产物的生成。以苯系物为研究对象，对DPDBD方法中所用催化剂进行筛选与组合， 分析不同催化剂的降解特性，探索不同催化剂之间的协同作用机理，考察各种因素对降解效果的影响。同时，通过对产物及活性基团的检测，深入分析该方法处理苯系物的降解机理及路径。

我国大气“十三五”规划已经明确将VOCs列为气态污染物的总量控制对象，开发高效地控制VOCs污染的防治技术是大气环境治理领域的重点研究方向。本项目开发了新型的具有多功能区的多段式介质阻挡放电（MPDBD）方法和新型的双管式填充床介质阻挡放电（Double-tube packed bed catalytic dielectric barrier discharge, DPDBD）方法，实验结果表明：DPDBD反应器和MPDBD反应器均比传统的单段式填充床DBD反应器，如TiO2填充床DBD反应器，在提高矿化率的同时有效地减少了副产物NOx和O3的生成，并初步阐述了这两种新方法对苯系物的降解机理--将污染物分子进行分段式降解的理论，即使污染物先经过氧化能力相对较弱的区域，来实现低能化学键的彻底矿化及高能化学键的弱化作用；而后进入氧化能力较强的区域，来实现这些中间产物的彻底矿化。且通过对比研究发现，与MPDBD反应器相比，DPDBD反应器具有更优地抑制副产物的效果。同时以矿化率和副产物的产量为最终目标，优化了MPDBD以及DPDBD反应器的结构参数以及对这两种反应器的主要工业运行参数进行了考察，本项目开发的两种新方法均可有效地拓宽DBD技术处理VOCs的浓度范围，为DBD技术的实际应用提供了理论和技术支持。