Composite polyelectrolyte multilayer membranes for oligosaccharides nanofiltration separation.

In the present work, composite polyelectrolyte multilayer (C-PEM) membranes were fabricated by using layer-by-layer (LbL) assembly technique for oligosaccharides nanofiltration (NF) separation. Specifically, the (chitosan/poly(styrene sulfonate) (PSS))3 multilayers designated as the middle layer (ML) were first deposited on the hydrolyzed polyacrylonitrile (PAN) ultrafiltration membranes, which were designated as the support layer. Then, the (poly(allylamine hydrochloride) (PAH)/PSS)2 multilayers designated as the top layer (TL) were deposited on the ML to form C-PEM membranes. When utilized for oligosaccharides NF separation, C-PEM membranes exhibited desirable performance compared to single-paired PEM membranes such as (PAH/PSS)5 and (chitosan/PSS)5 membranes owing to the collaboration of the TL and ML. In detail, C-PEM membranes acquired a permeation flux of 3.7±0.3 L m(-2) h(-1), 100% rejection of oligosaccharides and 63.0±0.5% rejection of glucose along with a high maltose/glucose selectivity of 46, demonstrating the promising potential for one-step membrane separation of oligosaccharides mixture.