Preparation and characterization of glutaraldehyde crosslinked chitosan nanofiltration membrane

In this article, we prepare chitosan (CS) membrane on polyacrylonitrile (PAN) ultrafiltration membrane, and utilize the protonated amine group (? NH₃⁺) on the CS to retain γ‐aminobutyric acid (GABA) in a solution with a pH condition below the amino acid isoelectric point, so as to separate the amino acid from a mixture with sodium acetate that simulates the amino acid fermentation broth. To improve the acid resistance of the composite membrane, we chelate the amine groups on the CS by copper sulfate first, then crosslink the hydroxyl groups in glutaraldehyde solution, and remove the copper ion in hydrochloric acid finally to release the amine groups. This crosslinked CS/PAN composite membrane achieves 95% GABA rejection in pH 4.69 solution under the operation pressure of 0.2 MPa, while over 90% of the sodium acetate permeates the membrane. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013