Characteristics of biochar derived from the co-pyrolysis of corn stalk and mulch film waste

The characteristics of biochar produced from the co-pyrolysis of corn stalk (CS) and mulch film (MF) were analyzed. Cellulose, hemicellulose, lignin were applied to explore the synergistic effects of CS and MF during co-pyrolysis. Upon increasing the proportion of MF, the yield of liquid products increased, and the yield of solid products decreased. Interactions of cellulose, hemicelluloses, and lignin, during the pyrolysis of CS were promoted. The content of CO and CO2 increased when the proportion of MF was 25%, but the content of CO decreased upon increasing the proportion of MF. When the MF content increased from 25% to 75%, the calorific values of the co-pyrolysis gases were respectively 0.43, 1.15, and 1.49 times higher than those when CS was pyrolyzed alone. In addition, analysis of biochar characteristics showed that the specific surface area of biochar produced from the co-pyrolysis of CS and MF increased by 0.54, 0.21, and 1.36 times, respectively, compared with that of CS pyrolysis. The number of oxygen-containing functional groups was decreased, and most hydroxyl and carboxyl groups decomposed when the content of MF was 25% during co-pyrolysis. These results indicate that a lower MF content during co-pyrolysis can promote the fuel characteristics of biochar.