A generalized model for predicting adsorption equilibria of various volatile organic compounds on activated carbon in the presence of supercritical carbon dioxide

摘要

A generalized model for predicting the adsorption equilibria of various VOCs (volatile organic compounds: acetone, toluene, n-hexane, n-octane, n-decane, methanol, ethanol, 2-propanol, and propylene glycol mono methyl ether (PGME)) on activated carbon in supercritical carbon dioxide (scCO(2)) was proposed. The two fitting parameters W-0,W-VOC (saturated adsorption capacity of activated carbon for VOC) and E-VOC (interaction energy between VOC and adsorbent) of the Dubinin-Astakhov (DA) equation, determined with the correlations to experimental adsorption equilibrium data, were found to be closely related to the density of CO2 and properties of VOCs, which could be generalized based on the physical meanings of each parameter. The generalized DA parameters were able to reproduce the adsorption equilibria of the various VOCs in scCO(2) to within 30% of the average relative deviation over a wide range of temperature and pressure conditions for most of the VOCs.