Pervaporation separation of water-isopropyl alcohol mixture by PVA/LiBr membrane

Hydrophilic polyvinyl alcohol membranes, modified by lithium bromide, were prepared with glutaraldehyde as a crosslinking reagent. The membranes were investigated for the pervaporation dehydration of a water-isopropyl systems. The effect of the feed temperature on permeation flux and membrane selectivity was studied. The characterization of modified membranes was performed using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC) and X-ray diffraction. It was observed that the crystallinity of membranes increased as lithium bromide was added to the polymer. High performance liquid chromatography (HPLC) was used to analyze water content and isopropyl alcohol in the feed and permeate samples The pervaporation tests also confirmed an enhancement in water permeability through adding LiBr to the polymer, because of the high hydrophilic properties of this salt. According to pervaporation experiments conducted at 50 degrees C, the water flux increased from 0.1049 kg/ m(2) hr to 0.1114 kg/ m(2) hr as 0.5 wt% of LiBr was added to the polymer matrix. Furthermore, an addition of 1 wt% of LiBr compared to homogeneous PVA membrane increased selectivity from 76 to 779. POLYM. ENG. SCI., 59:E101-E111, 2019. (c) 2018 Society of Plastics Engineers