Statistical optimization to improve N and C efficiency in biochar from model systems

To maximize the efficiency of the N and C conversion into solid product, the co-carbonization of cellulose with nitrogen-containing compounds (such as lysine and melamine) was studied in this work. The combinations of temperature, acid concentration, and cellulose to N-compound ratio were chosen as affecting factors using a central composite design. Response Surface Methodology (RSM) was applied to enhance the responses of the variables. Based on experimental data, various statistical models were created to calculate the effectiveness of N and C conversion. To compare the coefficients in the two scenarios (as expected vs. actual), statistical analysis was utilized. For lysine, the best N-conversion efficiency was achieved with a 10 wt% blending ratio, a 4 wt% acid impregnation, and carbonization temperature of 275 degrees C. The optimal factors for melamine to produce the highest N-efficacy were 7 wt% blending ratio, 4 wt% acid-impregnation, and 200 degrees C co-carbonization temperature.