Preparation, characterization and application of β-cyclodextrin-glutaraldehyde crosslinked membrane for the enantiomeric separation of amino acids Original Research Article

The polysulfone membrane (PS) and β-cyclodextrin glutaraldehyde crosslinked polysulfone membrane (β-CDXM) were prepared by phase inversion technique from the solutions prepared by solubilizing polysulfone polymer, β-cyclodextrin in N, N-dimethyl formamide (DMF) and adding glutaraldehyde. The membranes were extensively characterized by various techniques including attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM) and atomic force microscopy (AFM) to correlate membrane characteristics with their performance. ATR-FTIR and XRD studies indicated strong hydrogen bonding interactions between polysulfone and glutaraldehyde crosslinked (XβCD) network. TGA indicates a different range of thermal degradation due to change in enthalpy and presence of crosslinked structure. The membranes were tested by performing separation of enantiomers from racemic phenylalanine (Phe) and racemic tryptophan (Trp) in reverse osmosis. The results of experiments indicated that incorporation of β-cyclodextrin in polysulfone polymer had provided enantiomer discriminating capability to the membrane therefore β-CDXM had exhibited enantioselectivity for D-Phe and D-Trp. The observation confirmed that chiral environment is essential for enantiomer separation. The maximum enantioselectivity (> 81%) was observed for the D-Phe.