Membrane separation processes: Optical resolution of lysine and asparagine amino acids

Enantioselective thin film composite polymer membranes were prepared by interfacial co-polymerization of l-arginine with trimesoyl chloride in-situ on polysulfone ultrafiltration membrane. The chemical compositions of composite membranes were determined by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Membranes are characterized by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The optical resolution of α-amino acids was performed in pressure driven separation mode. The performances of membranes were compared in terms of flux, permselectivity, enantioselectivity and separation factor. The composite membranes exhibited 64-78% separation of amino acids. The membrane permeated d-enantiomers preferentially such that enantiomeric excesses of ~ 92% for d-enantiomer of lysine in permeates were achieved. The corresponding separation factors (α) were in the range of 4-21. As an immediate application, this study would help us design more efficient, nature-inspired selective chiral membranes that are able to separate enantiomers of chiral species.