Analysis and comparison of the composition, functional groups, sorption characteristics and surface structure of biochar affected by biomass feedstock

Biochar is the perfect solution to reduce the adverse effects of climate change by adopting viable solutions inspired by nature. Since biochar can be made from a variety of different sources, the paper aims to compare the properties of biochar made from different sources, including wood, sunflower, and rice husk. The results obtained from the elemental analysis showed that there are no exceeding the maximum permissible concentrations of trace elements in any of the samples. Moreover, it was found silicon oxide is presented in rice husk. IR spectroscopy of wood biochar and sunflower husk biochar showed the presence of hydroxyl functional groups and aliphatic C-H groups of cellulose, as well as phenolic functional groups and esters. In addition, the total surface area of the wood biochar and rice husk biochar is found to be highest and lowest, respectively. It was found that the total volume of pores in the following descending order rice husk>wood>sunflower. The SEM and 3D confocal microscopy results indicate that wood biochar contains the surface with the most upside-down as compared to other samples. The XRD demonstrated that wood and sunflower husk biochar samples take crystallinity from cellulose compared to rice husk biochar. TGA results manifested that the wood biochar is more stable, and the new step as the decomposition of lignin part results by increasing the temperature up to 500 °C. The addition of all the biochars to the soil (Сalcaric Fluvic Arenosols) increases the sorption capacity of the soil under mono- and polyelement contamination by copper, zinc, and lead.

This study was supported by RFBR project no. 19-05-50097, Grant of the President of Russian Federation project no. МК-6137.2021.1.5 and by the Strategic Academic Leadership Program of the Southern Federal University ("Priority 2030").