Dehydration of bioethanol produced from argane pulp using pervaporation membrane process: Experimental, molecular dynamics and GCMC simulation studies

Abstract

Pervaporation process would be a promising method for bioethanol recovery and dehydration from fermentation broth thanks to its eco-friendly and energy-saving characteristics. Herein, hydrophilic and dense polyvinyl alcohol (PVA) based membranes were prepared, characterized and employed to concentrate bioethanol recovered by distillation from argane pulp fermentate, through pervaporation process. Prepared membranes were characterized using Fourier transform infrared spectroscopy (FTIR), and their intermolecular interactions were studied using density and swelling experiments. The effects of water content (in wt%; from 5 to 50%) and temperature (303 to 323 K) of the feed mixture on pervaporation performance were investigated. The obtained experimental data showed that swelling degree is increased with increasing the water content in the feed mixture. The selectivity of prepared membranes decreased, and total flux increased with increasing temperature and water content. Moreover, ethanol was concentrated from 90% to 97%. Besides, molecular dynamics (MD) simulations and Grand Canonical Monte Carlo (GCMC) simulation were used to investigate the performance of membranes toward penetrant molecules from a theoretical point of view. Some theoretical parameters such as mean-square displacement (MSD), fractional accessible volume (FAV), sorption behavior of water/ethanol mixture were extracted to study the mobility and diffusivity of water and ethanol molecules inside PVA membranes. Theoretical results were in good consistency with experimental ones.