Soot aggregate restructuring during water processing

详细信息    查看全文

• 作者：Xiaofei Ma ; Christopher D. Zangmeister ; Julien Gigault ; George W. Mulholl ; Michael R. Zachariah
• 关键词：Differential mobility analyzer ; Aerosol particle mass analyzer ; Mass-mobility scaling exponent ; Light scattering ; Capillary force ; XPS
• 刊名：Journal of Aerosol Science
• 出版年：December, 2013
• 年：2013
• 卷：66
• 期：Complete
• 页码：209-219
• 全文大小：1874 K

文摘

Soot aggregate restructuring is explored in laboratory prepared soot particles upon exposure to high humidity environment followed by rapid water evaporation. Soot was generated in a Santoro style ethylene diffusion burner, and condensation of water on the soot particles was realized in a temperature-controlled water growth tube. The structure transformation of soot particles under different humidity conditions was monitored using a Differential Mobility Analyzer - Aerosol Particle Mass Analyzer (DMA-APM) and Tandem Differential Mobility Analyzer (TDMA) methods. The primary measured properties were mass-mobility scaling exponent, particle mass and mobility size before and after processing. A critical saturation ratio was observed above which aggregate restructuring occurred. The morphological change was visualized by taking electron microscopic images. X-ray photoelectron spectroscopy (XPS) analysis found that the chemical structures of different processed soot were indistinguishable. To assess if soot collapse occurred during water condensation or evaporation, water-coated soot was directly injected into water, where multi-angle light scattering showed that the structure was uncollapsed. This result indicates that soot restructuring driven by capillary forces occurs during evaporation, not condensation.