Evaluation of CH4 and CO2 adsorption on HKUST-1 and MIL-101(Cr) MOFs employing Monte Carlo simulation and comparison with experimental data

Many researches related to the simulation and experimentation of gas storage on HKUST-1 and MIL-101(Cr) metal organic frameworks (MOFs) are conducted to provide a green living environment. To achieve better understanding of adsorption capability of these MOFs, it is necessary to understand the limitations between simulation and the actual experiments. Both HKUST-1 and MIL-101(Cr) are undergone methane and carbon dioxide adsorption through grand canonical Monte Carlo (GCMC) simulation and experimental investigation by a volumetric apparatus. The amount of CH4/CO2 uptakes obtained from GCMC simulations are compared with experimental data for (i) the temperatures ranging from 130 K to 298 K and pressures up to 600 kPa (for CH4) and (ii) the temperatures varying from 303 K to 343 K and pressures up to 10 bar (for CO2). The simulation results are to be found consistent with the experimental data within 5-10% error ranges. However GCMC exhibits overestimation at higher pressures. Two strong adsorption sites due to Coulomb and van der Waals attractions toward CH4/CO2 molecules are found from the observation of simulation results in MOF structures. The isosteric heat of adsorptions is also calculated employing Clausius Clapeyron relation as well as GCMC simulation.