Structural changes of CAST soot during a thermal–optical measurement protocol
<p>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 <span class="inline-formula">>44</span> % for elemental carbon. One major cause...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2019-07-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/12/3503/2019/amt-12-3503-2019.pdf |
| _version_ | 1818547545794674688 |
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| author | T. Haller C. Rentenberger J. C. Meyer L. Felgitsch H. Grothe R. Hitzenberger |
| author_facet | T. Haller C. Rentenberger J. C. Meyer L. Felgitsch H. Grothe R. Hitzenberger |
| author_sort | T. Haller |
| collection | DOAJ |
| description | <p>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 <span class="inline-formula">>44</span> % 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 <span class="inline-formula"><sup>∘</sup>C</span>) 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 <span class="inline-formula"><sup>∘</sup>C</span>
increases the graphitic domain size within the material from 1.6 to 2 <span class="inline-formula">nm</span>.
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.</p> |
| first_indexed | 2024-12-12T08:08:11Z |
| format | Article |
| id | doaj.art-72ffac5f85cb46ccad909edce9204203 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-12T08:08:11Z |
| publishDate | 2019-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-72ffac5f85cb46ccad909edce92042032022-12-22T00:31:53ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482019-07-01123503351910.5194/amt-12-3503-2019Structural changes of CAST soot during a thermal–optical measurement protocolT. Haller0C. Rentenberger1J. C. Meyer2L. Felgitsch3H. Grothe4R. Hitzenberger5Faculty of Physics, University of Vienna, Vienna, 1090, AustriaFaculty of Physics, University of Vienna, Vienna, 1090, AustriaFaculty of Physics, University of Vienna, Vienna, 1090, AustriaInstitute of Materials Chemistry, TU Wien, Vienna, 1060, AustriaInstitute of Materials Chemistry, TU Wien, Vienna, 1060, AustriaFaculty of Physics, University of Vienna, Vienna, 1090, Austria<p>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 <span class="inline-formula">>44</span> % 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 <span class="inline-formula"><sup>∘</sup>C</span>) 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 <span class="inline-formula"><sup>∘</sup>C</span> increases the graphitic domain size within the material from 1.6 to 2 <span class="inline-formula">nm</span>. 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.</p>https://www.atmos-meas-tech.net/12/3503/2019/amt-12-3503-2019.pdf |
| spellingShingle | T. Haller C. Rentenberger J. C. Meyer L. Felgitsch H. Grothe R. Hitzenberger Structural changes of CAST soot during a thermal–optical measurement protocol Atmospheric Measurement Techniques |
| title | Structural changes of CAST soot during a thermal–optical measurement protocol |
| title_full | Structural changes of CAST soot during a thermal–optical measurement protocol |
| title_fullStr | Structural changes of CAST soot during a thermal–optical measurement protocol |
| title_full_unstemmed | Structural changes of CAST soot during a thermal–optical measurement protocol |
| title_short | Structural changes of CAST soot during a thermal–optical measurement protocol |
| title_sort | structural changes of cast soot during a thermal optical measurement protocol |
| url | https://www.atmos-meas-tech.net/12/3503/2019/amt-12-3503-2019.pdf |
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