School of Automotive and Traffic Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China.
Environ Sci Technol. 2020 Feb 18;54(4):2510-2519. doi: 10.1021/acs.est.9b06177. Epub 2020 Jan 27.
To investigate the effect of nonthermal plasma (NTP) on the microstructure and oxidation characteristics of particulate matter (PM) from diesel engines at different oxidation stages, a self-designed NTP reactor was used to conduct a time-varying oxidation test on PM samples. The oxidized PM samples were analyzed via thermogravimetric analysis and Raman spectroscopy. The results indicated that the effect of NTP could allow the elemental carbon (EC) to more easily start ignition. The oxidation activity of the EC decreased when the action time of the NTP was less than 5 min. Conversely, when the NTP action time was more than 5 min, the EC oxidation activity gradually increased. When the NTP was active for more than 10 min, it rapidly reacted with the EC, and the oxidation priority of the volatile fraction was higher than that of the EC. During the oxidation process, there are many forms of carbon structures in the particles and they have a mutual transmission relationship. The variation trend of the graphitization degree was consistent with that of the thermogravimetric results, indicating that the degree of graphitization directly affected the PM oxidation activity.
为了研究非热等离子体（NTP）对不同氧化阶段柴油机颗粒物（PM）微观结构和氧化特性的影响，采用自行设计的 NTP 反应器对 PM 样品进行了时变氧化试验。利用热重分析和拉曼光谱对氧化后的 PM 样品进行了分析。结果表明，NTP 的作用可以使元素碳（EC）更容易点燃。当 NTP 的作用时间小于 5 分钟时，EC 的氧化活性降低。相反，当 NTP 作用时间超过 5 分钟时，EC 的氧化活性逐渐增加。当 NTP 作用时间超过 10 分钟时，它与 EC 迅速反应，挥发性组分的氧化优先级高于 EC。在氧化过程中，颗粒中存在多种形式的碳结构，它们具有相互传递关系。石墨化程度的变化趋势与热重结果一致，表明石墨化程度直接影响 PM 的氧化活性。
