Dehydration of C₂–C₄ alcohol/water mixtures via electrostatically enhanced graphene oxide laminar membranes

The dehydration of alcohol/water mixtures using pervaporation membranes requires less energy than is required by conventional separation technologies. In this paper, we report electrostatically enhanced graphene oxide (GO) membranes for the highly efficient pervaporation dehydration of C₂–C₄ alcohol/water mixtures. Positively charged molecules were introduced as the interlayer of negatively charged GO layers via layer-by-layer assembly, thereby creating an electrostatic attraction that drives the assembly of GO nanosheets into ordered interlayer channels. The effects of the feed temperature, water concentration, and continuous operation on the membrane transport behavior were systematically investigated. In the dehydration of 90 wt% alcohol/water mixtures at 70°C, the membrane exhibited ethanol/water, isopropanol/water, and n-butanol/water fluxes of 2.35, 2.98, and 4.69 kg/(m² hr), respectively, as well as separation factors for the same mixtures of 3,390, 5,790, and 4,680, respectively. This excellent alcohol/water dehydration performance outperforms those of state-of-the-art polymeric membranes and GO-based membranes.