Preparation and optimization of nanocomposite membranes for ethanol dehydration via pervaporation by using response surface methodology

Abstract

Background

Alcohol dehydration using pervaporation, as a fast-developing process, requires more facilitation by improving their membrane performance.

Methods

Graphene oxide nanosheets (GONs) were incorporated into blend matrixes of chitosan (CS) and polyvinyl-alcohol (PVA) to prepare nanocomposite membranes (NCMs) for ethanol dehydration. The membranes' structure was evaluated using SEM and FTIR analysis and their dehydration performance was studied against membrane composition (GONs loading and the CS/PVA blending ratio) and operational variables (feed temperature and ethanol concentration) using response surface methodology.

Significant Findings

SEM images revealed GONs uniform dispersion within the membrane matrix and the FTIR results revealed the hydrogen bonds formation and minor changes after GONs incorporation. The optimum NCM was selected as 50 wt. % CS/PVA blended polymer matrix loaded by 4 wt. % GONs with permeation flux (PF) and separation factor (SF) were improved by 50 % and 5-fold, to 299 g/m²h and 1142. Its PF and SF reached 418 g/m²h (45 % increment) and 652 (30 % decrement) as its temperature elevated from 50 to 70 °C. These values were measured as 311 g/m²h (25 % decline) and 1106 (66 % improvement) by increasing the feed's ethanol content from 80 to 90 wt. %.