Forward osmosis, reverse osmosis, and distillation membranes evaluation for ethanol extraction in osmotic and thermic equilibrium

Abstract

One of the significant challenges of the industry is the economic extraction of ethanol from aqueous solutions of interest to the food industry. Specifically, in the alcoholic beverages industry, the non-alcoholic beverage market has gained importance, demanding more non-alcoholic drinks with higher organoleptic quality. In this context, the technology related to the use of membranes has shown great potential. Our research aims to determine the performance of forward osmosis using FO, RO, and MD membranes as an option in the extraction of alcohol in an osmotic (Δπ = 0) and thermal (ΔT° = 0) equilibrium process. The results showed that all the membranes have the potential to dealcoholize a 12% v.v. synthetic ethanol solution. The results showed that Membrane Distillation is a viable strategy as a complement in a hybrid FO-MD approach, achieving ethanol flux values close to those offered by FO membranes and much higher than those shown by RO membranes. We also proposed other technical criteria for membrane performance evaluation, such as maintaining a low reverse salt flux and a low or no water flux to keep the organoleptic properties of a hypothetical alcoholic beverage subjected to the FO-MD hybrid process. For a high Ethanol/Salt flux ratio, the RO-82V and FO-CTA membranes presented the best performance. Furthermore, in an Ethanol/Water flux ratio, RO membranes perform best when working in an osmotic equilibrium process with a water flux equal to zero. Regarding the FO membranes, in an Ethanol/Water flux ratio, the FO-TFC membrane presented the best performance.