Light absorption properties and molecular compositions of water-soluble and methanol-soluble organic carbon emitted from wood pyrolysis and combustion

Dissolved organic carbon was obtained by extracting POA with methanol and pure water. The absorption spectra, functional groups, and molecular composition of the dissolved organic carbon were measured and analyzed.

The results found that dissolved organic carbon under nitrogen conditions had higher light absorption properties than dissolved organic carbon under air conditions and that methanol-soluble organic carbon had a higher light absorption capacity than water-soluble organic carbon. These results are attributed to the higher molecular weight, unsaturation, and modified aromaticity of methanol-soluble organic carbon compared to water-soluble organic carbon; and dissolved organic carbon under nitrogen has a higher molecular weight, unsaturation, and modified aromaticity than that under air.