Equilibrium and kinetic studies of the dehydration of ethyl alcohol-water mixture via locally synthesized activated starch

Abstract

Batch kinetic process was employed in the evaluation of the dehydration of ethyl alcohol-water mixture via locally synthesized activated starch from cassava and maize. The equilibrium data generated were analyzed using adsorption isotherm and kinetic mechanism model equations. Results showed that the optimum concentration of 74.07% was obtained when 4g of modified cassava starch was contacted with 70ml of ethyl alcohol of initial concentration 69.72% at a contact time of 20min where the volume of ethyl alcohol recovered was 65ml. The maize starch could only achieve 72% optimum concentration when same 4g of modified maize starch was used with 70ml of ethyl alcohol with an initial concentration of 68.15%, at a contact time of 20 min where 60 ml of ethyl alcohol was recovered. The adsorption isotherm was studied using two well-known models; Langmuir and Freundlich. Although results showed that the adsorption process obeyed both models, however, the Freundlich model gave a better fit with an R² value of 0.984 as against 0.974. The kinetic study on the other hand showed that the adsorption process obeyed the pseudo-second order.