Kinetics and Mechanism Study of Different Types of Surface-Imprinted Polymers for CO2 Adsorption

Abstract

The increased level of CO2 in the atmosphere has led to global warming and climate change. To mitigate these problems, solid adsorbents have become attractive materials for capturing excess CO2 in the post-combustion method. Molecularly imprinted polymer (MIP) can be applied to prepare highly selective adsorbents that could capture CO2 molecules. The MIP was prepared using the surface imprinted polymer technique in this preliminary work. Only two types of support materials were used (graphite and silica gel) to screen the best support material that could enhance the CO2 adsorption capacity of the resulting adsorbent, which was analyzed using a fixed-bed column reactor. Graphite-imprinted polymer (GMIP) was found to be a good potential for CO2 adsorption. The Avrami model best described the adsorption system, while the fixed-bed curve data fit the Yoon–Nelson model well. The semi-empirical method was used to assess the interaction mechanism of the molecularly imprinted polymer with CO2 during adsorption. This investigation involved testing four different ratios of the template complex to functional monomers. The ratio of 1:4 (CO2:Allylthiourea) demonstrated the highest binding energy, with a higher formation of hydrogen bonds. Film diffusion and intraparticle diffusion were the main rate-limiting steps that played vital roles at different stages of CO2 adsorption. This preliminary work has enhanced the development of MIP for CO2 adsorption and showcased the integration of computational approaches in tailoring specific MIPs.