Xenon storage density and its energy flow through adsorption on metal–organic frameworks

Abstract

The global demand for Xe storage and separation increases significantly over the coming decades for various applications ranging from ion propulsion to nuclear power plants. Due to very low amount of Xe in the earth's atmosphere and the complexity of cryogenic storage facilities, the storage and recovery of Xe in porous adsorbents such as MOFs (metal–organic frameworks) are an important research area. The research activities on adsorption-assisted Xe storage include (i) the synthesis of adsorbents with greater micropore distribution and large micropore volume and (ii) the Xe storage capability in the form of isotherms and kinetics. But the thermodynamic properties such as enthalpy, internal energy, entropy and density can judicially be applied to simulate the energetic and storage performances of Xe gas in structural porous adsorbents. Therefore, this manuscript presents the thermodynamic formulations of entropy flow, generation and adsorbed phase density of MOFs + Xe systems. Secondly, these parameters are evaluated for Xe adsorption on MIL-100 (Fe), MIL-101(Cr), UiO-66(Zr) and FMOF(Zn) MOFs at temperatures changing from 233 K to 303 K and pressures up to 100 kPa. A deeper understanding of Xe storage capacity on MOFs is presented by temperature–density maps. Furthermore, the entropy and temperature maps are plotted to identify the internal energy storage capacity of Xe in MOFs storage cells under charging and discharging conditions of Xe.