The effects of interactions between fiberboard-derived volatiles and glucose-derived biochar on N retention and char structure during the decoupled pyrolysis of fiberboard and glucose using a double-bed reactor

This study aims to examine the capability of nascent glucose-derived char on absorbing and solidifying N-containing gas species from the pyrolysis of fiberboard. A specially designed double-bed quartz reactor was used to carry out the experimental work. The N chemical forms and carbon structure in chars were characterized using XPS and Raman techniques, respectively. The results clearly indicate that the glucose char could effectively retain N-containing volatiles, especially at low temperatures due to its high content in O functional groups. The occurring forms of N inherently existing in fiberboard-derived char showed different transforming patterns from those in the glucose chars where the N compounds (e.g., amide-N) were externally obtained by intensive volatile-char interactions. The in-situ DRIFT analysis showed that the amino groups released from fiberboard may react with the aldehyde groups containing in the glucose char and form N-doped aromatic rings. Additionally, although the increase in carrier gas (thus decreasing the volatile-char interaction time) did not affect the N retention, the carbon structure revealed by Raman analysis dramatically altered.