In the present study, it was observed that the HK sample (the AC
by chemical activation using H3PO4 followed by chemical
activation with KOH) exhibited relatively high adsorption capacity
of up to 4.10 mmol/g at 1 bar and 303 K, compared with those
obtained AC using other adsorbents. This led to an increase of
about 63% in comparison with the commercial AC (Table 4).
Furthermore, it should be mentioned that in this study the
comparable CO2 adsorption capacity of the AC prepared with
H3PO4, ZnCl2, KOH and the commercial AC are in the following
order: HK > H2> Z0.75> commercial AC.