Characterization of Surface Functional Groups in Corn Stover Biochar Derived from Microwave-assisted Pyrolysis

Abstract

Abstract. In this study, the biochar was prepared by microwave assisted pyrolysis of corn stover at atmospheric pressure and different reaction temperatures and time. Central composite experimental design (CCD) was used in the optimization of volatile (bio-oil and syngas), biochar production, and the amount of carbon surface functional groups. Mineral and GC/MS analysis were used to study the pyrolysis of corn stover. Various types of oxygen containing functional groups (carbonyls, phenolics, lactones, and carboxyls) on the biochar were quantified by means of titrimetric techniques using a modified Boehm’s method. The chemical composition of the biochar was characterized by FTIR. The research result indicates that the surface area and functional groups of biochar were significantly influenced by the pyrolysis temperature and time. A prediction model was satisfactorily developed to describe the development of carbon surface functional groups. Modification and characterization of biochar surface functional groups is a new way to improve or extend their catalytic application in biomass conversion and bio-oil upgrading.