CO₂ Physisorption over an Industrial Molecular Sieve Zeolite: An Experimental and Theoretical Approach

The present work studies the adsorption of CO₂ using a zeolitic industrial molecular sieve (IMS) with a high surface area. The effect of the CO₂ feed concentration and the adsorption temperature in conjunction with multiple adsorption-desorption cycles was experimentally investigated. To assess the validity of the experimental results, theoretical calculations based on well-established equations were employed and the values of equilibrium, kinetic, and thermodynamic parameters are presented. Three additional column kinetic models were applied to the data obtained experimentally, in order to predict the breakthrough curves and thus facilitate process design. Results showed a negative correlation between temperature and adsorption capacity, indicating that physical adsorption takes place. Theoretical calculations revealed that the Langmuir isotherm, the Bangham kinetic model (i.e., pore diffusion is the rate-determining step), and the Thomas and Yoon-Nelson models were suitable to describe the CO₂ adsorption process by the IMS. The IMS adsorbent material maintained its high CO₂ adsorption capacity (>200 mg g^-1) after multiple adsorption-desorption cycles, showing excellent regenerability and requiring only a mild desorption treatment (200 °C for 15 min) for regeneration.