Evaluation of H2 and CO2 adsorption into MIL-88A-Fe by grand canonical Monte Carlo simulation
Abstract
Two of the global issues are finding new, clean energy sources to replace increasingly exhausting fossil fuels and overcome the problem of environmental pollution and climate change. In recent years, organic-metal framework series has been considered as a great candidate for H 2 storage and CO 2 capture to provide clean energy and reduce environmental pollution. Among them, MIL-88A-Fe has a stable and flexible structure in moist environments and high porosity. Therefore, in this research, hydrogen (H 2 ) storage and carbon dioxide (CO 2 ) capture capacities in MIL-88A-Fe were assessed quantitatively. By the grand canonical Monte Carlo simulation, the adsorption capacities of MIL-88A were elucidated via the adsorption isotherms, heats of adsorption at finite temperatures of 77 K and 298 K and pressures up to 100 bar. The results show that parameterizing force fields by combining DDEC method to calculate atomic partial charges for electrostatic interactions and the universal force field parameters for the Lennard-Jones interactions provide a quick and reliable method to evaluate gas capture and storage capacities of porous materials. The results also indicate that the abilities of H 2 storage and CO 2 capture of MIL-88A-Fe in gravimetric capacities were not very high; however, they were noticeable in volumetric capacities. The hydrogen molecule is strongly adsorbed in the hollow positions of O and Fe atoms, while the CO 2 molecule is more evenly distributed in the sorbent.