Separation of ethanol–water liquid mixtures by adsorption on BPL activated carbon with air regeneration

• A process to separate ethanol–water mixtures on BPL activated carbon has been proposed.
• BPL activated carbon can be used to separate C2H5O–H2O mixtures, due to hydrophobicity.
• The liquid phase adsorption kinetics of ethanol–water mixtures has been modelled.
• The desorption kinetics of the adsorbent has been modelled.

Nowadays there is a growing interest in the use of renewable energy sources such as bioethanol. The difficult separation of ethanol from the fermentation broth still hinders the industrial production of bioethanol. In this paper the recovery of ethanol from aqueous mixtures by adsorption is studied. The solution proposed is a concentration temperature swing adsorption process (CTSA), using a commercial granular activated carbon (BPL 4 × 10) as adsorbent. Modelling processes is of importance because the entire design can be done using laboratory experimental data. An adsorption–desorption cyclic process to separate ethanol–water mixtures on BPL activated carbon and the regeneration process has been modelled. Ethanol and water isotherms on BPL activated carbon in the liquid phase, ethanol adsorption isotherm in the vapour phase, and kinetic parameters needed to model the whole process have been obtained experimentally.