A comprehensive review on ionic liquids and ionic hybrid materials for CO2 separation

Global warming is caused by anthropogenic carbon dioxide (CO2) emissions in the atmosphere, and different options have been proposed to mitigate CO2 emissions, where CO2 separation plays an important role. To develop cost-effective technologies for CO2 separation, immobilizing ionic liquids (ILs) into porous materials demonstrates potential. Different ILs are strategically immobilized into different porous materials like MOFs, activated carbons, pops, and silica, resulting in IL-porous composites with the functional properties of the pristine porous materials and the peculiar physicochemical of the immobilized ILs. These progressive developments reveal novel opportunities in separation science. In this review, we discuss the functionalization of ILs for CO2 separation. We also highlight several porous materials, such as MOFs, carbon nanotubes, zeolites, carbonaceous materials, and graphene. Finally, we demonstrate the development of hybrid ionic materials composed of ILs and porous materials, especially MOFs, to provide a perspective on the potential of ILs/porous material composites for CO2 separation. The most significant opportunities and challenges in ILs/porous materials as well as their synthesis methods, characterization techniques, applications, and future possibilities are thoroughly explored to develop a roadmap for CO2 separation. Considering future developments in this field, the design and development of these innovative hybrid materials and their potential to replace conventional materials are also carefully evaluated.