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°C and 550°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°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 350ºC had a lower content of functional groups and lower hydrophilicity compared to biochars produced at 550ºC. The pyrolytic process significantly changed the elemental composition, porosity, and morphological properties of biochars. Both temperatures, 350°C and 550°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.  

24.3.2019