Urea impregnation into fungus pretreated corn stover to perform pyrolysis for production of nitrogen-containing bio-oil and nitrogen-doped biochar

Urea was introduced into the fungal pretreated corn stover and then the urea soaked materials were subjected to pyrolysis for the production of nitrogen-containing bio-oil and nitrogen-doped biochar. The urea soaking effectively realized the enrichment of nitrogen-containing compounds in the bio-oil and the maximal content of the nitrogen-containing compounds in bio-oils reached up to 66.32% under 4 wt% urea concentration. Among the nitrogen-containing compounds, amines were the most dominant component with the maximal content of 41.17%. The higher urea concentration is beneficial to make more nitrogen be fixed in the biochar. The nitrogen content of the biochar reached up to 12.86 wt% under 8 wt% urea concentration. Nitrogen on the biochar surface existed in the form of pyrrolic-N, pyridinic-N and graphite-N. In conclusion, urea simple soak on fungus pretreated biomass to perform pyrolysis is a promising approach to obtain high value-added nitrogen-containing chemicals and nitrogen-doped biochar with high nitrogen content.