Offgas analysis and pyrolysis mechanism of activated carbon from bamboo sawdust by chemical activation with KOH

Bamboo sawdust was used as the precursor for the multipurpose use of waste. Offgases released during the activation process of bamboo by KOH were investigated quantitatively and qualitatively by a gas analyzer. TG/DTG curves during the pyrolysis process with different impregnation weight ratios (KOH to bamboo) were obtained by a thermogravimetric analyzer. Pyrolysis mechanism of bamboo was proposed. The results showed that the offgases were composed of CO, NO, SO2 and hydrocarbon with the concentration of 1 372, 37, 86, 215 mg/L, respectively. Thermogravimetric analysis indicated that the pyrolytic process mainly experienced two steps. The first was the low temperature activation step (lower than 300°C), which was the pre-activation and induction period. The second was the high temperature activation step(higher than 550°C), which was a radial activation followed by pore production. The second process was the key to control the pore distribution of the final product.