Studies on the performance of pervaporation for the separation of aqueous organic mixtures

Abstract

newline Pervaporation (PV) is gradually evolving from a novel approach into an efficient and eco-friendly unit operation in the arena of separation science and technology. It is widely touted as an advanced membrane process capable of efficient separation of heat sensitive volatile organic components or azeotropic mixtures which are otherwise difficult to achieve by conventional means. In the present study pervaporation of model and actual wastewater consisting of acetic acid (HAc), ethylene glycol (EG), and vinegar was extensively investigated using commercial, modified and synthesized polymeric composite membranes, for a wide range of operating conditions. Comparative swelling/sorption study of the as prepared membranes was carried out effectively using the gravimetric method at different temperature including room temperature. The degree of swelling for graphene oxide (GO) incorporated and borax cross-linked membranes was found to be increased almost linearly with increasing water concentration. The addition of more cross-linker may also increase the swelling charecteristics of the prepared polymeric membranes. Effect of several physico-chemical parameters such as feed concentration, feed temperature and feed flow rate on the pervaporation flux, separation factor, pervaporation separation index (PSI) and enrichment factor (EF) were critically analyzed with respect to their existing theories. There was disproportionality between the permeate flux and separation factor for all feed compositions and operating temperatures. The rate of increase of molar flux of water with temperature was found to be substantially higher than acetic acid. The apparent activation energy of water permeation was observed to be significantly lower, suggesting a higher separation efficiency of the prepared membranes. Intrinsic membrane properties like partial permeability, permeance and selectivity as well as the mechanical properties like tensile strength, elongation at break and modulus of elasticity of the newly prepared polyvi