results from our previous study.22) The treatment with diluted sulfuric acid did not influence pore struc- ture, because the BET surface area and total pore volume hardly changed by the treatment with diluted sulfuric acid. In the study by Maruyama et al.,21) the BET surface area and pore volume decreased due to the loading of many acidic functional groups by the liquid phase oxidation using (NH4)2S2O8. However, in this study, a few acidic functional groups were loaded and the BET surface area and pore volume hardly changed due to using diluted sulfuric acid as a weak oxidizing agent.
Adsorption of Ammonia Gas
The combined adsorption isotherms and strong adsorption isotherms of ammonia are shown in Figs.1 and 2, respectively. The adsorbed amount on BC400 and AC in the combined adsorption isotherms was higher than that of BC700 and BC1000, and that of BC400 was highest. The pore volume of AC from the results of the nitrogen adsorption isotherms