Carbon dioxide and methane capture in metal-organic framework MIL-101(Cr) at high pressure

Abstract

Due to the presence of high CO2 amounts in the natural gas stream, a variety of efforts have been employed in the search for more efficient materials for the separation of gaseous mixtures such as CO2/CH4. In this article, a metal-organic framework (MIL-101) was synthesized and characterized, which showed a wide surface area (2924.8 m2 g−1 per BET) and a high volume of pores (1.32 cm³ g−1 per DFT). This structure was used to study the adsorption capacity of CO2 and CH4 within systems pressurized up to 100 bar - where a high adsorption capacity of CO2 was evidenced under 45 °C. Moreover, it was possible to distinguish between the high selectivity of this structure for CO2 molecules and its low capture of CH4 molecules. Also, the high stability of MIL-101 was noted after 6 cycles of adsorption and desorption of CO2 under 50 bar and 45 °C, thereby maintaining its adsorption capacity and crystallinity. Finally, isotherms of CO2 adsorption were successfully adjusted with the use of the Toth model.