THE CHARACTERIZATION OF THE MICROPORE STRUCTURES OF SOME ACTIVATED CARBONS OF PLANT-ORIGIN BY N2 AND CO2 ADSORPTIONS

In this study, active carbons prepared from almond and hazelnut shells under various experimental conditions were investigated. Merck-2514 a nd Merck-2184 active carbons were used for comparison. N2 (77 K) gas a nd CO2 (273 and 195 K) gas adsorptions were determined as comparison c riteria. Regarding the specific surface area and micropore volume resu lts obtained from these adsorption data, it is concluded that N2 (77 K ) adsorption by itself is inadequate in the characterization of active carbons which are low-sized microporous dominated. In addition, it is concluded that it would be useful to investigate CO2 (195 and 273 K) adsorption. The iodine and methylene blue tests at 298 K were also app lied for the characterization of the carbon adsorbents mentioned. From these data it was seen that the iodine test can be applied as a total porosity indicator and that the methylene blue test can be used as a developed microporosity indicator. These results indicate that the bes t adsorbents were those prepared from hazelnut shells. Depending on th e preparation conditions, the physically activated carbon has an activ ation time up to 4 hours and has adsorption properties on the level of Merck commercial carbons.