Adsorptive removal of CO_2 on highly microporous activated carbons prepared from Eucalyptus camaldulensis wood: Effect of chemical activation

摘要

series of activated carbons (ACs) were prepared from Eucalyptus camaldulensis wood by chemical activation with H_3PO_4, ZnCl_2 at different impregnation ratios as well as by pyrolysis, followed by activation with KOH. The porosity characteristics of these ACs were determined by N_2 adsorption isotherms. Through varying the H_3PO_4/biomass ratio from 1.5 to 2.5, the prepared ACs displayed BET surface areas in the range of 1875–2117 m~2/g with micropores content of 69–97%. For the ZnCl_2 activated series, BET surface areas varying from 1274.8 to 2107.9 m~2/g with micropores content of 93– 100% were obtained from impregnation ratios of 0.75–2.0. The AC obtained by KOH had the largest BET surface area of 2594 m~2/g and the high micropore content of 98%. In addition, the FTIR and SEM analyses conducted for characterizing the ACs and the CO_2 adsorption onto all series of the eucalyptus wood based ACs at pressures ranging from 0 to 16 bar using a volumetric method were investigated. Also the effect of temperature (15–75 ℃) on the amount of CO_2 adsorbed by the ACs that was prepared with H_3PO_4, KOH and ZnCl_2 was studied. The CO_2 adsorption capacity on the AC prepared with KOH was up to 4.10 mmol/g at 1 bar and 303 K, having an increase of about 63% in comparison with the commercial AC.