Structural changes of CAST soot during a thermal–optical measurement protocol
- Author(s)
- Theresa Haller, Christian Rentenberger, Jannik C. Meyer, Laura Felgitsch, Hinrich Grothe, Regina Hitzenberger
- Abstract
Thermal–optical measurement techniques are widely used to classify carbonaceous material. The results of different methods for total carbon are comparable but can vary by >44 % for elemental carbon. One major cause of variation is the formation of pyrolyzed carbon during the heating process which occurs mainly in samples with a high amount of brown carbon (BrC). In this study the structural changes of two different CAST (combustion aerosol standard) aerosol samples caused by the heating procedure in a thermal–optical instrument were investigated with UV–VIS and Raman spectroscopy, the integrating-sphere technique (IS) and transmission electron microscopy. All analysis techniques showed significant structural changes for BrC-rich samples at the highest temperature level (870 ∘C) in helium. The structure of the heated BrC-rich sample resembles the structure of an unheated BrC-poor sample. Heating the BrC-rich sample to 870 ∘C increases the graphitic domain size within the material from 1.6 to 2 nm. Although the Raman spectra unambiguously show this increase in ordering only at the highest temperature step, UV–VIS and IS analyses show a continuous change in the optical properties also at lower temperatures. The sample with a negligible amount of BrC, however, did not show any significant structural changes during the whole heating procedure.
- Organisation(s)
- Aerosol Physics and Environmental Physics, Physics of Nanostructured Materials
- External organisation(s)
- Technische Universität Wien
- Journal
- Atmospheric Measurement Techniques
- Volume
- 12
- Pages
- 3503–3519
- No. of pages
- 17
- ISSN
- 1867-1381
- DOI
- https://doi.org/10.5194/amt-12-3503-2019
- Publication date
- 07-2019
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103042 Electron microscopy, 103039 Aerosol physics, 105208 Atmospheric chemistry
- Keywords
- ASJC Scopus subject areas
- Atmospheric Science
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/structural-changes-of-cast-soot-during-a-thermaloptical-measurement-protocol(3e4fcf6c-fb06-4bf5-82d4-1793f4cdaa5a).html