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Novel sodium alginate/polyethyleneimine polyion complex membranes for pervaporation dehydration at the azeotropic composition of various alcohols

Devi, D. Anjali, Smitha, Biduru, Sridhar, Sundergopal, Jawalkar, Sheetal S., Aminabhavi, Tejraj M.
Journal of chemical technology and biotechnology 2007 v.82 no.11 pp. 993-1003
Fourier transform infrared spectroscopy, X-ray diffraction, alcohols, ambient temperature, crosslinking, crystal structure, differential scanning calorimetry, glutaraldehyde, ion exchange, permeability, pervaporation, scanning electron microscopy, sodium alginate, sorption, thermal stability, water quality
Dense polyion complex membranes of anionic sodium alginate (NaAlg) and cationic polyethyleneimine (PEI) were prepareand crosslinked with glutaraldehyde for dehydration of alcohol-water mixtures by pervaporation (PV). The membranes were characterized by ion-exchange capacity measurement, Fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy to investigate the extent of cross-linking, intermolecular interactions, thermal stability, and surface and cross-sectional morphologies, respectively. Wide-angle X-ray diffraction was used to investigate the crystallinity of the membranes. PV dehydration characteristics of the membranes were determined as a function of PEI content, crosslinking time as well as feed water composition. Transport parameters such as sorption, diffusion and permeability of water and alcohols through the membranes were determined. Among the four different membrane compositions, the polyion complex containing 40% PEI was found to yield optimum separation data in terms of membrane stability, selectivity and permeability. On the other hand, 10% PEI-containing membrane gave the highest selectivity with the lowest flux at ambient temperature, but the membranes were not sufficiently stable.