In this study, a carbon molecular sieve (CMS) was synthesized from walnut shells, followed by physical activation of the carbon content of the CMS. Adsorption of CO2 and CH4 onto raw and acid treated adsorbents were investigated using two sizes, 300?600 and 600?1180 ?m. The adsorbents were impregnated with two solvent mixtures of waste engine oil with kerosene and with thinner at a proportion of 1:1 at 25?C. The highest adsorption for CO2 and CH4 was obtained at the suitable size of a group of CMS(A) adsorbents, with acid treated adsorbents being more efficient than the raw adsorbents. The acid treated CMS(A-3) sample adsorbed 0.925 mol CO2 g-1 and 0.353 mol CH4 g-1. The results indicated that by decreasing the granulation size of group CMS(R) adsorbents, the adsorption capacities for CO2 and CH4 were reduced while increasing the granulation size of group CMS(A) adsorbents resulted in an enhancement in the adsorption capacity for CO2 and CH4. Moreover, acid treated adsorbents achieved enhanced adsorption capacity for CO2 and CH4. Further modifications reduced the adsorption capacity for CO2 and CH4 in impregnated adsorbents, due to a decrease in surface area, pore volume and pore size of the adsorbent.
Unusually Low Heat of Adsorption of CO2 on AlPO and SAPO Molecular Sieves
