Abstract. This research aims to study the physical-chemical characteristics and carbon dioxide adsorption using commercial activated carbon (GAC) by comparing with commercial activated carbon. Chemical vapor deposition (CVD) of carbon molecular sieve prepared from activated carbon (CMSGAC) was prepared using acetylene at various conditions, such as temperature, time and acetylene flow rate. The results indicated that CMSGAC had high adsorption capacity and high selectivity for the adsorption ratio between carbon dioxide and methane. The experiments were carried out by using the samples of GAC, CMSGAC, and commercial carbon molecular sieve (CMSCOM) for adsorption of mixed gas of 30% CO2, 20% N2, and 50% CH4, respectively. The results showed that the adsorption efficiency at 50% of inlet carbon dioxide concentration of GAC, CMSGAC, and CMSCOM was at 85, 114, and 140 min, respectively. The purity of methane was 81.53, 93.16, and 98.26%, respectively. The selectivity for the adsorption ratio between carbon dioxide and methane was 1.32, 16.52, and 24.89, respectively. The cycle time of the samples was 3, 7, and 8 cycles, respectively. Finally, the maximum adsorption capacity of the samples was 1.74, 3.26, and 4.06 mole CO2/kg absorbent, respectively.

The effect of carbon dioxide (CO2) on global warming is serious problem. The adsorption with solid sorbents is one of the most appropriate options. In this study, the most interesting adsorbent is granular activated carbon (GAC). It is suitable material for CO2 adsorption because of its simple availability, many specific surface area, and low-cost material. Afterwards, GAC was impregnated with chitosan solution as impregnated granular activated carbon (CGAC) in order to improve the adsorption capacity of GAC. This research aims to compare the physical and chemical characteristics of GAC and CGAC. The experiment was carried out to evaluate the efficiency of CO2 adsorption between GAC and CGAC. The results indicated that the iodine number of GAC and CGAC was 137.17 and 120.30 mg/g, respectively. The Brunauer-Emmett-Teller results (BET) of both GAC and CGAC show that specific surface area was 301.9 and 531.3 m 2 /g, respectively; total pore volume was 0.16 and 0.29 cm 3 /g, respectively; and mean diameter of pore was 2.18 and 2.15 nm, respectively. Finally, the CO2 adsorption results of both GAC and CGAC in single column how the maximum adsorption capacity was 0.17 and 0.25 mol/kg, respectively; how degeneration time was 49.6 and 80.0 min, respectively; and how the highest efficiency of CO2 adsorption was 91.92% and 91.19%, respectively.