Towards the dehydration of ethanol using pervaporation cross-linked poly (vinyl alcohol)/graphene oxide membranes

Highly hydrophilic inorganic material graphene oxide (GO) was successfully prepared and incorporated into a cross-linked poly(vinyl alcohol) (PVA) matrix. The obtained mixed matrix membranes (MMMs) have been used for the dehydration of ethanol (10:90% water-ethanol) by pervaporation (PV), monitoring their performance in terms of total permeate flux, partial components fluxes, as well as their separation factor. The effect of filler was analyzed by doubling the GO content (at 0.5, 1.0, and 2.0 wt.%) in the MMMs. A complete analysis of the operating temperature (between 40-70 °C) was carried out by means of Arrhenius relationship. Moreover, the membranes were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), measurements of degree of swelling (uptake), water contact angle (CA) and mechanical properties. At 40 °C, the best performance was provided by the MMMs containing 1 wt.% GO, showing a separation factor of 263 and a permeate flux of about 0.137 kg m-2 h-1 (in which 0.133 kg m-2 h-1 corresponds to water). This represents a 75% enhancement of the original permeation rate of pristine cross-linked PVA membranes. Taking into account the promising results, it is likely that these MMMs will provide featured benefits in green processes, e.g. ethanol purification by means of less-energy consumption.