Drastically different restructuring of airborne and surface-anchored soot aggregates

Document Type

Article

Publication Date

2-1-2023

Abstract

Combustion soot particles are fractal aggregates of hydrophobic spherules. Mixing of soot particles with other chemicals during atmospheric processing may partially offset their hydrophobicity, promoting water uptake and structural compaction. We investigated morphological changes in fractal soot particles coated by sulfuric acid and then humidified, both in airborne and surface-bound states. Airborne soot was probed by tandem differential mobility analysis. Surface-bound soot was studied in a controlled microenvironment of a closed cell, using environmental transmission electron microscopy. After humidification, the airborne particles became fully compact, but the deposited particles showed only minor morphological changes despite significant water uptake. Although minor, those changes were detected during both water condensation and evaporation, indicating that condensation-evaporation cycles play an important role in atmospheric soot compaction. Lesser restructuring of deposited aggregates was caused by surface anchoring and coating loss, making anchoring an indispensable tool for preserving morphology of aggregates against changing experimental environment.

Identifier

85145595987 (Scopus)

Publication Title

Journal of Aerosol Science

External Full Text Location

https://doi.org/10.1016/j.jaerosci.2022.106103

e-ISSN

18791964

ISSN

00218502

Volume

168

Grant

AGS 1463702

Fund Ref

National Science Foundation

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