Comparative Analysis of Methods of Activated Carbon Surface Area Determination

Abstract

 This work sought to determine the surface area (SA) of prepared activated carbons from palm kernel shells by two methods and to do a comparative analysis of the results obtained. The methylene blue adsorption test (MBT) gave a surface area in the range of 418 to 544 m²/g for the nine prepared activated carbons labelled A1 to C3. The surface area (S_N2) obtained by nitrogen gas adsorption< However, ranged from 17 to 217 m²/g. The surface area obtained for the prepared activated carbons by the MBT decreased in the following order: A1 > A2 > C1 > A3 > B1 > B3 > B2 > C2 > C3, while the BET surface area obtained by nitrogen adsorption for the activated carbons was in the order: A1 > A2 > A3 > C1 > B3 > B1 > B2 > C3 > C2. The order shows a comparable trend and it can be deduced that while the MBT measured the mesopore volume of the activated carbon, the nitrogen gas adsorption measured the micropore volume.  The MBT was therefore in good agreement with the nitrogen gas adsorption method and can therefore provide a cheaper and affordable method to characterize the surface area of activated carbon.