Adsorption Equilibrium Data of Hexyl Acetate on Activated Carbon under Supercritical CO₂ Conditions

Abstract

The regeneration of spent activated carbon that captures alkyl acetate, a major volatile organic compound (VOC) in the printing field, is extremely important for economic and environmental implications. The use of supercritical CO 2 avoids the high heat associated with conventional thermal methods that can degrade the carbon. However, existing research on this is limited in scope, and more comprehensive studies are needed to fully understand the technology. In this study, a fixed-bed adsorption method was used to investigate the adsorption of hexyl acetate on activated carbon in supercritical CO 2 at T = (313−353) K and P = (10−20) MPa. The results are consistent with previous studies on similar VOCs and show the influence of temperature and pressure on adsorption equilibria. Hexyl acetate showed higher adsorption than propyl acetate and ethyl acetate, which may be due to its different volatility in supercritical CO 2 and its different affinity for the absorbent used. The analysis using the Dubinin−Astakhov (DA) equation offers a quantitative understanding of how supercritical CO 2 density and VOC molecular size influence adsorption equilibria. This insight is essential for developing an efficient and eco-friendly regeneration method for the printing industry utilizing supercritical CO 2 .