Aggregation Kinetics of Diesel Soot Nanoparticles in Wet Environments

作者：Chen Chengyu; Huang Weilin^*

来源：Environmental Science & Technology, 2017, 51(4): 2077-2086.

DOI：10.1021/acs.est.6b04575

Soot produced during incomplete combustion consists mainly of carbonaceous nanoparticles (NPs) with severe adverse environmental and health effects, and its environmental fate and transport are largely controlled by aggregation. In this study, we examined the aggregation behavior for diesel soot NPs under aqueous condition in an effort to elucidate the fundamental processes that govern soot particle particle interactions in wet environments such as rain droplets or surface aquatic systems. The influence of electrolytes and aqueous pH on colloidal stability of these NPs was investigated by measuring their aggregation kinetics in different aqueous solution chemistries. The results showed that the NPs had negatively charged surfaces and exhibited both reaction- and diffusion-limited aggregation regimes with rates depended upon solution chemistry. The aggregation kinetics data were in good agreement with the classic Derjaguin Landau Verwey Overbeek (DLVO) theory. The critical coagulation concentrations (CCC) were quantified and the Harnaker constant was derived for the soot (1.4 X 10(-20) J) using the colloidal chemistry approach. The study indicated that, depending upon local aqueous chemistry, single soot NPs could remain stable against self-aggregation in typical freshwater environments and in neutral cloud droplets but are likely to aggregate under salty (e.g., estuaries) or acidic (e.g., acid rain droplets) aquatic conditions or both.

• 出版日期2017-2-21
• 单位rutgers