Fabricating graphene oxide-based ultrathin hybrid membrane for pervaporation dehydration via layer-by-layer self-assembly driven by multiple interactions

Graphene oxide (GO)-based ultrathin hybrid membranes with thicknesses less than 115nm were fabricated via layer-by-layer (LbL) self-assembly driven by multiple interactions. Gelatin (GE) and GO were alternately deposited on hydrolyzed polyacrylonitrile (H-PAN) ultrafiltration membranes through electrostatic attraction, hydrogen bond, and hydrophobic interaction to obtain hybrid multilayer membranes. The incorporation of GO favored the coverage of nanopores on H-PAN membrane, which greatly reduced the required deposition cycles for acceptable permselectivity of membrane, and then simplified the membrane-fabrication procedure. Enhanced thermal stability of GE molecules was obtained for as-fabricated hybrid multilayer membranes compared with GE/H-PAN pristine membrane. In membrane separation experiments, the hybrid multilayer membrane achieved synchronous enhancement in permeation flux and separation factor for pervaporation dehydration of ethanol aqueous solution in comparison with GE/H-PAN pristine membrane. The pH value of 4.0 was determined as the optimal condition of self-assembly process in terms of separation performance. The optimized separation performance of hybrid multilayer membranes with the bilayer number 10.5 was obtained with the permeation flux of 2275g/m²h and water content in permeate of 98.7wt% under the conditions of 350K and water content in feed of 20wt%. Desirable operation stability was acquired in the long-term membrane separation experiment.