Abstract:
Spent coffee grounds was used to be a precursor for the production of carbon molecular sieve (CMSCF) to compare physical and chemical characteristics including CO2 adsorption. The production of CMSCF was carried out by using activated carbon activated with KOH was starting material. Then, activated carbon produced from coffee grounds (GK) was deposited by acetylene in chemical vapor deposition to compare with carbon molecular sieve prepared from commercial activated carbon (CMSGAC), commercial carbon molecular sieve (CMSCOM), and commercial activated carbon impregnated with chitosan solution (CGAC). Analytical results show that the specific surface area of samples, such as CMSCF, CMSGAC, CMSCOM, and CGAC was 453.0, 604.0, 558.6, and 531.3 m3/g, respectively. The iodine number of samples was 239.5, 325.3, 295.4, and 204.2 mg/g, respectively. Afterwards, the experiment of CO2 adsorption in single adsorption column at 3 atm with the ratio of flow rate (inlet/outlet) of 1 at 25 °C in the mixed gas of 20% N2, 30% CO2, and 50% CH4 was carried out. The purity of CH4 in the samples was 95.20, 93.16, 98.26, and 82.72, respectively. The degeneration time in CO2 adsorption of samples was 120, 114, 140, and 90 min, respectively. The selectivity of samples in the ratio between CO2 and CH4 was 19.41, 16.53, 24.89, and 1.54, respectively. Finally, the maximum CO2 adsorption capacity of samples was 3.42, 3.26, 4.06, and 2.58 mol/kg, respectively.