FT-IR analysis and the content of phenolic compounds in exogenous organic matter produced from plant biomass

Pyrolysis causes changes in physical and chemical properties of plant biomass, which consequently determine its further use. For this reason, this study aimed at: (i) comparing the effect of the temperature of a pyrolytic process (350 degrees C and 550 degrees C) on the content of total phenolic compounds (TPC) and water soluble phenolic compounds (WSPC) in plant biomass and biochars; (ii) verifying changes in the content of functional groups identified by the FT-IR method; and (iii) assessing the elemental composition, porosity, and morphological properties of plant biomass before and after pyrolysis. The FT-IR analysis showed that biochars produced at 550 degrees C underwent partial decomposition of hemicellulose, cellulose, and lignin, in addition to which the temperature affected the degradation of aromatic C fractions. Biochars produced at 350 degrees C had a lower content of functional groups and lower hydrophilicity compared to biochars produced at 550 degrees C. The pyrolytic process significantly changed the elemental composition, porosity. and morphological properties of biochars. Both temperatures, 350 degrees C and 550 degrees C, significantly decreased the content of total and water soluble phenolic compounds. Morphological analysis of biochars revealed that biochars retained the specific surface area and pore volume similar in value to these parameters measured in the feedstocks from which they had been produced. The pyrolysis of wheat and miscanthus straw also reduced the polarity (O+N)/C in biochars, which is a desirable finding, testifying to the development of functional groups.