Soot nanoparticles produced under different operating conditions have been analysed using two different techniques, one to determine the different contributions of total carbon, i.e. thermo-optical-transmission analysis and another to characterize the particle carbon structure, i.e., Raman spectroscopy analysis. Particularly the first analysis allowed dividing the total carbon into three different fractions: organic, pyrolytic and elemental carbon. Once the amounts of organic carbon and elemental carbon were calculated it was also possible to evaluate the mass absorption coefficient, in fact, various studies have shown a correlation with OC/EC fraction. The goal is to determine if and how combined TOT and optical/spectroscopic measurements allow monitoring nanoparticles formed under "clean-like" combustion conditions and differentiate them from those produced in sooting flames with the perspective to improve the carbon balance in the atmosphere and to consolidate source apportionment. The study has included an analysis of four samples: two samples of young and mature particles belong to the nucleation particles, namely particles with a size of the order of 2-4 nm and other two soot samples, belong to the category of the so-called primary or grown soot particles. The results show that the amount of EC is higher for mature that young soot whiles the amount of OC has an opposite behaviour indicating a similar trend in the graphitization order of the different soot particles. This observation was also confirmed by the Raman spectroscopy analysis.
THERMO-OPTICAL-TRANSMISSION OC/EC AND RAMAN SPECTROSCOPY ANALYSES OF FLAME-GENERATED CARBONACEOUS NANOPARTICLES
S Bocchicchio;M Commodo;P Minutolo
2021
Abstract
Soot nanoparticles produced under different operating conditions have been analysed using two different techniques, one to determine the different contributions of total carbon, i.e. thermo-optical-transmission analysis and another to characterize the particle carbon structure, i.e., Raman spectroscopy analysis. Particularly the first analysis allowed dividing the total carbon into three different fractions: organic, pyrolytic and elemental carbon. Once the amounts of organic carbon and elemental carbon were calculated it was also possible to evaluate the mass absorption coefficient, in fact, various studies have shown a correlation with OC/EC fraction. The goal is to determine if and how combined TOT and optical/spectroscopic measurements allow monitoring nanoparticles formed under "clean-like" combustion conditions and differentiate them from those produced in sooting flames with the perspective to improve the carbon balance in the atmosphere and to consolidate source apportionment. The study has included an analysis of four samples: two samples of young and mature particles belong to the nucleation particles, namely particles with a size of the order of 2-4 nm and other two soot samples, belong to the category of the so-called primary or grown soot particles. The results show that the amount of EC is higher for mature that young soot whiles the amount of OC has an opposite behaviour indicating a similar trend in the graphitization order of the different soot particles. This observation was also confirmed by the Raman spectroscopy analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
