Preparation of activated carbons from corn cob catalyzed by potassium salts and subsequent gasification with CO2

In the present study, granular activated carbons were prepared from agricul tural waste corn cob by chemical activation with potassium salts and/or phy sical activation with CO2. Under the experimental conditions investigated, potassium hydroxide (KOH) and potassium carbonate (K2CO3) were effective ac tivating agents for chemical activation during a ramping period of 10 degre esC/min and subsequent gasification (i.e., physical activation) at a soakin g period of 800 degreesC. Large BET surface areas (>1600 m(2)/g) of activat ed carbons were thus obtained by the combined activation. In addition, this study clearly showed that the porosity created in the acid-unwashed carbon products is substantially lower than that of acid-washed carbon products d ue to potassium salts left in the pore structure. (C) 2001 Elsevier Science Ltd. All rights reserved.