Adsorption breakthrough and cycling stability of carbon dioxide separation from CO₂/N₂/H₂O mixture under ambient conditions using 13X and Mg-MOF-74

Carbon dioxide and storage is an efficient method to reduce the emitted CO₂ from the burning of fossil fuels. Zeolite-based materials are conventional adsorbents used to adsorb some gasses involving carbon dioxide. Mg-MOF-74 is an eminent reticular material among adsorbents due to its good CO₂ capacity at low pressures (10–20 kPa). In this study, an experimentally validated model is used to report the H₂O effect on CO₂ separation using 13X and Mg-MOF-74 under ambient conditions. A computational model has been developed using ANSYS Fluent program linked by user-define-function (written in C). The adsorption breakthrough results show that a humid CO₂/N₂ mixture, under 300 K, 86% RH, 101.3 kPa, could slightly reduce the CO₂ adsorption capacity by about 0.05% and 6% for 13X and Mg-MOF-74, respectively (at CO₂ adsorption breakthrough saturation). Regardless of these reductions, Mg-MOF-74 has better adsorption capacity, even under humid ambient conditions, by about 5.77 mmol/g in a comparison to 2.27 mmol/g for 13X, respectively. Cycling stability over more than 90 cycles is also simulated; and shows that, a dehydration process is recommended to be carried out before the CO₂ separation process for efficient energy consumption and sustainable adsorbents. The total recyclable amounts of adsorbed CO₂ are about 0.94 and 3.07 mmol/g for 13X and Mg-MOF-74, respectively, under 101.3 kPa adsorption, 2 kPa desorption, 86% relative humidity, and 298 K. The cyclic CO₂ separation is found to be a robust method more than the breakthrough separation to evaluate the real adsorption capacities.