Research progress of Metal-Organic Frameworks (MOFs) in CO2 capture and transformation

With the progress of social and industrial modernization, the emission of carbon dioxide (CO2) and other greenhouse gases is increasing, resulting in serious greenhouse effect and frequent natural disasters. In order to reduce carbon emissions, it is imperative to develop carbon capture, utilization and storage technology (CCUS). At present, the commonly CO2 capture methods and transformation methods include chemical absorption method, adsorption separation method, membrane separation method, and CO2 catalytic reaction, etc. Among them, the development of efficient and stable adsorption and catalytic materials is the key to the optimization of various capture technologies. In this paper, the application of metal-organic frameworks (MOFs) in CO2 capture and conversion is reviewed in detail, the latest progress of current research is analyzed, and the problems and solutions in the application process are revealed. Compared with single metal MOFs, bimetallic MOFs have better metal defect sites and L acid content, showing good advantages in CO2 adsorption separation and catalytic reaction. The functional modification method can be modified according to the needs of different CO2 capture technologies, and has a high success rate, especially the post-functionalization method, which is widely used in CO2 capture due to its simple modification method and good structure maintenance. Pre-functionalization is the most ideal modification method for MOFs, especially ligand functionalization, which can essentially change the affinity of MOFs to CO2. However, the maintenance of MOFs structure is a major difficulty in current research. The preparation of MOFs nanofluid absorbent can effectively increase the heat and mass transfer inside the absorbent, improve the agglomeration of traditional nanoparticles, facilitate the formation of stable suspension, and increase the amount of CO2 absorption. But the viscosity control of absorbent is the barrier of current research. In addition, as a filling material in membrane separation method, MOFs can effectively improve the selectivity of membrane due to its good compatibility and abundant surface functional groups. At the same time, the high CO2 adsorption of MOFs can improve the CO2 capacity of the membrane, but the mechanical properties and cyclic stability of MOFs membrane need to be further optimized. Although there are many studies on CO2 capture technology by MOFs, the literature on CO2 capture system and economic analysis is limited. Starting from the preparation cost, CO2 capture cost and regeneration cost of MOFs, this study attempts to reveal the relationship between the chemical properties of MOFs and the process economy of CO2 capture.