Desorption of butanol from zeolite material

Sorption-based recovery of 1-butanol from aqueous solution has been investigated focusing on the recovery of butanol by desorption from the sorbate. Sorption isotherm, thermogravimetric adsorption and differential scanning calorimetry experiments have been used to determine the desorption behavior of butanol and water for two high-silica zeolite adsorbents, faujasite (CBV901) and ZSM-5 (CBV28014). Carbon dioxide can be used as displacement agent for butanol recovery, with the butanol-carbon dioxide equilibria determining the carbon dioxide mass requirement for such a process. For CBV901 desorption requires 2440 J/g of water and 1080 J/g of butanol. The heat effects for CBV28014 are 2730 J/g (water) and 1160 J/g (butanol). A significant difference in water content can be seen between both zeolite materials, with CBV28014 showing the least amount of water adsorption. The desorption rate of butanol from CBV28014 is significantly slower than from CBV901. A catalytic reaction, most probably dehydration, occurs around 200 degrees C during temperature programmed desorption of butanol from CBV28014. (C) 2012 Elsevier B.V. All rights reserved.