Raw natural gas contains methane as its major component, but it also contains considerable amounts of contaminants such as CO
2 and H
2S (i.e. acid gases) that can cause corrosion and fouling of the pipeline and equipment during transportation and liquefaction. Amine-based CO
2 gas removal processes have been employed in the gas industry, but these processes have disadvantages including high regeneration energy requirements and inefficiencies; these issues have not been adequately solved to date. Currently, adsorptive acid gas removal technologies have received significant interest because of the simplicity of adsorbent regeneration by thermal or pressure variation[1]. Numerous micro- and mesoporous adsorbents including zeolites [2-3], titanosilicates[4], activated carbons[5-6], metal-organic-framework (MOF) [7], and silica-alumina materials[8-9] were studied for this type of application. However, the CO
2/CH
4 selectivity of the aforementioned adsorbents was not high enough for commercial applications. In this study, different adsorbents including cation-exchanged zeolites and amine-modified MOFs were synthesized, physicochemically characterized, and evaluated for adsorptive removal of CO
2 from natural gas. The equilibrium isotherms of CO
2 and CH
4 on adsorbents in varied pressure were measured and compared. The ideal-adsorbed solution theory (IAST) was employed for the estimation of CO
2/CH
4 selectivity of those adsorbents.
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