Structural changes of CAST soot during a thermal–optical measurement protocol

Autor(en)

Theresa Haller, Christian Rentenberger, Jannik C. Meyer, Laura Felgitsch, Hinrich Grothe, Regina Hitzenberger

Abstrakt

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(en)

Aerosolphysik und Umweltphysik, Physik Nanostrukturierter Materialien

Externe Organisation(en)

Technische Universität Wien

Journal

Atmospheric Measurement Techniques

Band

12

Seiten

3503–3519

Anzahl der Seiten

17

ISSN

1867-1381

DOI

https://doi.org/10.5194/amt-12-3503-2019

Publikationsdatum

07-2019

Peer-reviewed

Ja

ÖFOS 2012

103042 Elektronenmikroskopie, 103039 Aerosolphysik, 105208 Atmosphärenchemie

Schlagwörter

ASJC Scopus Sachgebiete

Atmospheric Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/3e4fcf6c-fb06-4bf5-82d4-1793f4cdaa5a