Modeling, equilibrium and kinetics of CO₂ adsorption in LTA zeolite obtained from clay

Abstract

This paper discussed the synthesis of LTA zeolite from Pinheiro clay (PIN) aiming for adsorption of CO₂. To obtain the LTA-PIN zeolite, the PIN was submitted to acid treatment, followed by calcination and hydrothermal treatment. These treatments promoted the reorganization of the crystalline structure of the PIN, leading to the LTA-PIN zeolite with 95.79% purity confirmed by XRD, SEM, XRF, and FTIR results. The performance of the LTA-PIN zeolite was similar to the one of the standard LTA zeolite. The CO₂ adsorption by the zeolites could be properly described by the pseudo-second-order kinetic and Freundlich isotherm models, suggesting that physisorption was the main mechanism responsible for the deposition of CO₂ at the surface of the zeolites. According to regeneration results, LTA-PIN zeolite can be reused five times without significant loss of CO₂ adsorption capacity, contrary to the 12% reduction in CO₂ adsorption capacity presented by the LTA-standard zeolite.

Keywords: LTA zeolite; Pinheiro clay; modeling; adsorption of CO₂