Effect of Volatile-Char Interaction on Biochar Containing N/O-Functional Group During Reburning Denitrification

The influence of functional groups such as N/O and microcrystalline structure in biochar on NO reduction is critical. The interaction between volatile and char can significantly alter the activity of char, thereby altering its ability to reduce NO. Unfortunately, the impact of this interaction on NO reduction is still unclear. In this study, the effect of this interaction at 900 degrees C on the physicochemical structure of model biochar containing N/O-functional group during reburning denitrification was investigated. This paper simulates the volatile of reactive species containing H and O through pyrolysis of polyethylene and polyethylene glycol, respectively. The results indicate that the H- and O-containing reactive species play distinct roles during the interaction between volatile and char, but both species consume the amorphous carbon structure. The H-containing actives significantly increased the condensation of the aromatic rings and the O and N contents of the char decreased by 1.36% and 0.43% respectively. There were also significant interconversions between the N functional groups, with the content of N-5 increasing by 12% and that of N-6 by 2%. Consequently, the ability of char to reduce NO decreased by 29%. The O-containing reactive species will react with the char to form C-O composite oxides, thus increasing the O content with 1.88% and preventing the carbon structure from being condensed into a large aromatic ring system. Simultaneously, it was found that after the action of O-containing reactive species, the content of N decreased by 0.9%, and the N functional group tended to convert to N-5 (pyrrole or pyridone), increasing its content by 27%. Furthermore, char activity was significantly increased and NO reduction capacity increased by 19%. [GRAPHICAL ABSTRACT]