A volumetric system
was used to assess carbon-based adsorbents
for evaluation of the gas separation, equilibrium, and kinetics of
oxygen (O
2
), nitrogen (N
2
), and carbon dioxide
(CO
2
) adsorption on granular activated carbon (GAC) and
functionalized GAC at 298, 308, and 318 K under pressures up to 10
bar. The effects of ZnCl
2
, pH, arrangement of the pores,
and heat-treatment temperature on the adsorptive capabilities of O
2
, N
2
, and CO
2
were evaluated. High-performance
O
2
adsorption resulted with a fine sample (GAC-10-500)
generated with a 0.1 wt % loading of ZnCl
2
. The optimal
sample structure and morphology were characterized by field-emission
scanning electron microscopy, Fourier transform infrared spectroscopy,
and powder X-ray diffraction. On the basis of the adsorption–desorption
results, the fine GAC provides a surface area of 719 m
2
/g. Moreover, it possessed an average pore diameter of 1.69 nm and
a micropore volume of 0.27 m
3
/g. At 298 K, the adsorption
capacity of the GAC-10-500 adsorbent improved by 19.75% for O
2
but was not significantly increased for N
2
and
CO
2
. Isotherm and kinetic adsorption models were applied
to select the model best matching the studied O
2
, N
2
, and CO
2
gas uptake on GAC-10-500 adsorbent. At
298 K and 10 bar, the sip isotherm model with the highest potential
adsorption difference sequence and gas adsorption difference compared
with pure GAC adsorbent as O
2
> N
2
> CO
2
follows well for GAC-10-500. Eventually, the optimal sample
is more effective for O
2
adsorption than other gases.