Research progress on nanoconfined ILs in two-dimensional composite membranes for CO2 capture

Green and low-carbon is a development concept advocated by people all over the world, and the year-on-year increase in CO2 emissions has a tremendous impact on climate change and human production and life. Therefore, under such harsh environmental background, there is an urgent need to develop an efficient carbon capture, utilization and sequestration (CCS) technology to mitigate excessive CO2 emissions. As an emerging high-efficiency separation technology among many separation technologies, membrane separation technology has been widely used in many fields for its advantages of integrating separation, concentration, purification and refinement, high efficiency, energy saving, environmental protection, and simple and easy to control operation process. Among them, gas separation membrane technology has gradually become the main development direction of global carbon capture technology. Membrane materials are the core of the membrane, with the continuous emergence of new membrane materials, a series of high-performance gas separation membranes are emerging. Ionic liquids (ILs) have become a hot research topic in the field of CO2 separation due to their non-volatile, adjustable structure, outstanding stability, and excellent affinity for CO2, but their industrialized application is limited by high viscosity and high cost. Combining ILs with different 2D laminated membrane materials to obtain novel composite membranes with the advantages of both ILs and 2D laminated membrane materials has become one of the current trends in the field of ionic liquid research. For this reason, this review focuses on the research progress of confining ILs to different 2D laminate membranes with ILs as the centerpiece, and discusses the nature of ILs and the separation mechanism based on the existence between ILs and CO2 molecules. In addition, the application of gas separation membranes constructed with different ILs and 2D laminate materials for CO2 capture is presented. Finally, the advantages and challenges of IL in the field of gas separation are discussed, and future research directions and development opportunities are presented.