Preparation and characterization of activated carbon from cotton stalks in a two-stage process

Activated carbons are prepared from cotton stalks by chemical activation with ZnCl2, H2SO4 and physical activation using CO2 and steam–CO2 mixture for temperatures of 750, 850 and 900 °C. The effects of activation temperature and duration time, impregnation concentration of agent, impregnation times, and physical activating agent are examined. These materials are characterized by adsorption/desorption of N2 to determine the BET areas, thermogravimetric analysis (TG, DTA), FTIR and scanning electron microscopy (SEM). ZnCl2 under CO2 atmosphere was found more effective than H2SO4 as a chemical reagent under identical conditions in terms of porosity development. The maximum BET surface area is found to be 2053 m2/g for active carbons produced with ZnCl2 activation under CO2 atmosphere.