Enhanced CO <sub>2</sub> CH <sub>4</sub> separation using hydroxyl functionalized Mg-MOF-74
Syed Abdul Moiz Hashmi, Hina Moiz, Waqar Hussain, Minza Mumtaz
Abstract
The separation of carbon dioxide (CO2) from methane (CH4) is crucial for biogas upgrading and natural gas purification. In this study, Mg-MOF-74 was functionalized with 2,5-dihydroxy-1,4-benzenedicarboxylic acid (dobdc), introducing hydroxyl groups that enhance CO2 adsorption through hydrogen bonding and quadrupole interactions. The resulting Mg-MOF-74-dobdc exhibited a remarkable CO2 uptake of 9.12 mmol/g at 25 °C and 1 bar, surpassing unmodified Mg-MOF-74 and other leading adsorbents such as MIL-53(Al) and ZIF-8. This functionalization also significantly improved CO2/CH4 selectivity, exceeding 50 under low-pressure conditions. The synergistic effects of ligand functionalization enhanced adsorption capacity, exceptional selectivity, and operational robustness position Mg-MOF-74-dobdc as a promising benchmark for sustainable CO2 capture in challenging gas separation processes.