Influences of impregnation ratio and activation time on ultramicropores of peanut shell active carbons

Abstract We studied effects of impregnation ratio and activation time on ultramicropores of KOH-activated peanut shell active carbons (ACs). The ultramicropores were characterized in terms of ultramicropore volume ( V nm ), ultramicropore fraction ( V nm / V t ), and pore size distribution. The ultramicropores of the ACs were mostly in the range of 0.45–0.70 nm. Increasing the impregnation ratio from 1 to 3 first increased the V nm and V nm / V t , and then decreased them. Prolonging the activation time from 1 h to 2 h resulted in a minimum V nm / V t , but hardly affected the V nm . The AC with the highest V nm (0.11 ml/g) was obtained by activation for 1–2 h at an impregnation ratio of 2. The V nm bore a linear relationship with the CO 2 uptakes at 0.1 and 0.2 bar (0 °C). This research was significant for preparation of ACs with developed ultramicropores.