Water-selective Membrane from Crosslinking of Poly(vinyl alcohol) with Tartaric Acid and Its Pervaporation Separation Characteristics for a Water/Acetic Acid Mixture

The preparation of a water-selective membrane from the crosslinking of high molecular weight poly(vinyl alcohol) (PVA) with tartaric acid is reported. The resulting membrane was characterized by IR spectroscopy, swelling studies, differential scanning calorimetry, and contact angle testing, and was finally applied in the pervaporation. The performance of the membrane was evaluated in relation to the mixing ratio, changes in feed concentration, and changes in operating temperature. An optimum mixing ratio of 80:20 (wt %) of PVA to tartaric acid was determined, giving a flux range from 0.0072 to 0.095kg/m(2)h and a separation factor of 41.5-707.6 at 40-60 degrees C and 80-90wt % aqueous acetic acid feed solution. From an Arrhenius type of relationship, it was determined that flux varies exponentially with temperature. The activation energy was calculated for the permeation of each of component of the mixture, with a higher activation energy being observed for acetic acid than for water. From the separation index, it could be concluded that the membrane has good selectivity toward water and exhibits better performance at higher acetic acid concentrations.