What are the indicators of biochars for possessing higher aromaticity produced by slow pyrolysis process? Generally at higher temperatures the pyrolyzed biochars show higher aromaticity. What are the ways to identify?
Dear Sajib Aninda Dhar ,
as mentioned by Tamjid Us Sakib we can use FTIR to study the change (increase) in aromaticity. For example, you can plot the ratio of integrated areas at 3000–2800 cm-1 (aliphatic CHx stretching vibration) to 1650–1500 cm-1 (aromatic C=C ring stretching vibration) vs temperature to demonstrate the relative contents of aliphatic and aromatic functional groups of charcoal (Article FTIR spectroscopy and reflectance of modern charcoals and fu...
). The ratios of integrated areas at 900–700 cm-1 (aromatic CH out-of-plane deformation) to 1650–1500 cm-1 you can used as a measure of the degree of condensation of aromatic rings.Raman spectroscopy (
Article Assessment of the structural evolution of carbons from micro...
Article Carbonisation of biomass-derived chars and the thermal reduc...
) and 13C NMR (Article Reviewing, Combining, and Updating the Models for the Nanost...
) are also very useful analytical tools to study the aromaticity of biochars.
First of all, you can identify the functional groups in biochar by FTIR analysis. If the spectrum reveals the evolution of aromatic functional groups replacing aliphatic groups of biomass, it shows the increase of aromatic Carbon in biochar. Also, you can use the Van Krevelen diagram. If H/C and O/C values decrease with the increase of pyrolysis temperature, it is an identification of increase of aromaticity in biochar.
Dear Sajib Aninda Dhar ,
as mentioned by Tamjid Us Sakib we can use FTIR to study the change (increase) in aromaticity. For example, you can plot the ratio of integrated areas at 3000–2800 cm-1 (aliphatic CHx stretching vibration) to 1650–1500 cm-1 (aromatic C=C ring stretching vibration) vs temperature to demonstrate the relative contents of aliphatic and aromatic functional groups of charcoal (Article FTIR spectroscopy and reflectance of modern charcoals and fu...
). The ratios of integrated areas at 900–700 cm-1 (aromatic CH out-of-plane deformation) to 1650–1500 cm-1 you can used as a measure of the degree of condensation of aromatic rings.Raman spectroscopy (
Article Assessment of the structural evolution of carbons from micro...
Article Carbonisation of biomass-derived chars and the thermal reduc...
) and 13C NMR (Article Reviewing, Combining, and Updating the Models for the Nanost...
) are also very useful analytical tools to study the aromaticity of biochars.
Dear SA Dhar,
In principle, one could also examine the aromaticity of the biochars by
Pyr-GC/MS analysis. There are a number of studies in the literature that describe this procedure. Hope this helps.
Regards,
BBN
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