Carbon dioxide adsorption modeling to determine breakthrough curves in a fixed bed: isotherm and temperature effects

Abstract Carbon dioxide (CO 2 ) is a major greenhouse gas produced by anthropogenic activities, such as industrial processes and energy consumption. This study focuses on CO 2 adsorption, a widely used industrial method, specifically dynamic CO 2 capture from the atmosphere using ammonia-modified granular activated carbon (OXA-GAC). The research integrates experimental investigations with mathematical modeling to optimize the adsorption process. A numerical solution for mass balance equations, formulated from partial differential equations (PDEs), was implemented using the method of lines (MOL). To simulate the CO 2 breakthrough profile in the adsorption column, three kinetic models were employed: pseudo-first-order, pseudo-second-order, and Avrami. Among these, the Avrami model demonstrated the best fit, exhibiting the highest correlation factor with experimental kinetic data at 30 °C, 45 °C, and 60 °C. Furthermore, two equilibrium adsorption isotherms, Toth and Langmuir, were evaluated. For low CO 2 concentrations, the Yoon-Nelson model outperformed the Thomas model, particularly at 30 °C and 45 °C across all C/C 0 ratios. At 60 °C, the adsorption performance in the column was accurately represented by these models for C/C 0 ratios below 0.7. This study contributes to the advancement of CO 2 capture technologies by optimizing dynamic CO 2 adsorption using OXA-GAC. It provides valuable insights into process optimization under varying temperature and concentration conditions, supporting the development of more efficient and sustainable carbon capture systems.