Metal-Organic Frameworks for CO2 Separation from Flue and Biogas Mixtures

Great efforts have been made toward the separation of CO2 from flue gas and biogas to mitigate environmental pollution and the demand for renewable fuels, respectively. Nonthermal-based separations, such as adsorption-based or membrane-separation technology employing porous materials, are considered to be more promising than traditional cryogenic and absorption-based systems. Due to several advantages of metal-organic frameworks (MOFs) over other conventional porous materials, reports on flue and biogas separation by MOFs are burgeoning (423 for adsorption and 56 for membrane-based separations until June 2021) and demand urgent summarization. This review presents a bird's eye view on such separations while organizing the developed strategies and considering several performance parameters, such as trade-off between sorption capacity and separation selectivity in adsorption-based systems and permeability versus separation selectivity in membrane-based systems. In addition, the mechanisms involving such separations at the molecular level are presented. A critical discussion section offers more crucial insights into these materials from industrial deployment viewpoints. Finally, future recommendations are made for further developments of MOF materials as flue and biogas separators and thus toward solving both the challenging universal problems of global warming and energy scarcity simultaneously.