基于三甘醇附着对黑碳气溶胶形态结构变化的模拟

Effects of tri-ethylene glycol coating at the morphology of soot aerosol

为研究黑碳气溶胶粒子在附着三甘醇后形态结构的变化,本文通过采用甲烷和洁净空气燃烧制取黑碳气溶胶,并运用自主搭建的串联式差分电迁移率分析系统对黑碳气溶胶进行粒径筛选、热消解和三甘醇附着,同时结合扫描电镜仪和气溶胶质量分析仪观察分析黑碳气溶胶附着三甘醇后形态结构和质量的变化.通过筛选得到粒径为100 nm、200 nm和300 nm米的黑碳气溶胶粒子进行三甘醇附着模拟实验.由于黑碳气溶胶颗粒的特殊链状小球结构,使用热溶蚀器去除非元素碳物质后的黑碳气溶胶附着上三甘醇,发现粒径越大的黑碳气溶胶粒子越容易发生形态结构的变化,并且少量的三甘醇附着就能够显著促进这一形变过程的发生.因而,大气中存在的三甘醇能够在一定程度上促进黑碳气溶胶物理特性的改变,进而改变黑碳气溶胶对大气环境的影响.

In this study,we investigated the effects of tri-ethylene glycol（TEG） coating on the structure of soot aerosol particle. Soot from combustion of methane and clean air was size classified,thermally denuded and coated with TEG through a Tandem Differential Mobility Analyzer（TDMA）.Additionally,soot aerosol was characterized using scanning electron microscopy（SEM） and massmobility measurement by Aerosol Particle Mass analyzer（APM）. Soot aerosol with particle size of100 nm,200 nm and 300 nm were selected for TEG coating. Non-EC material was removed by Thermal Denuder（TD）. The morphology of larger particles changed much more significantly due to the special sphere-chain structure of soot. According to the experiment result,a small amount of TEG coating could induce significant restructuring of soot aggregates. Our results suggest that TEG in the atmospheric may change the physical properties of soot aerosol particle and alter the atmospheric impacts of combustion aerosols.