Preparation of high surface area activated carbons from tobacco stems with K2CO3 activation using microwave radiation

In this paper, activated carbons with high surface area from carbonized tobacco stems with K2CO3 activation by microwave radiation were investigated. Effects of microwave radiation time and K2CO3/C ratio on the yield and adsorption capacities of activated carbons were evaluated. Experimental results indicated that the optimum conditions were as follow: microwave power 700 W; microwave radiation time 30 min; K2CO3/C ratio 1.5:1. Iodine number, amount of methylene blue adsorption and the yield of activated carbon prepared under optimum conditions were 1834 mg/g, 517.5 mg/g and 16.65%, respectively. Surface area, micropore volume and pore size distribution (PSD) of the carbons were determined by the BET, H-K and DFT methods. Results showed that activated carbons had a micropore content about 59.98% and a small number of mesopores and macropores; BET specific surface area and total pore volume were 2557 m2/g and 1.647 cm3/g, respectively.