(462b) Hydrophobic Thin-Film Composite Membranes Coated with UV-Curable Fluoropolymer for Concentrating Pharmaceuticals and Food Additives in Organic Solvents

A UV-curable fluorinated polymer, perfluoropolyether (PFPE, Fluorolink^® AD1700), is coated and polymerized onto a cross-linked polyimide substrate to modify its surface properties for organic solvent nanofiltration (OSN). Different coating concentrations, ranging from 1 wt% to 10 wt%, are applied. The PFPE coating is found to convert the hydrophilic substrate to a hydrophobic membrane and narrow the pore size of the membrane to make it suitable for OSN applications. The prepared composite membranes are tested using various organic solvents (acetonitrile, ethanol, isopropanol and hexane) and the permeances of these solvents are found to be inversely proportional to the products of their viscosities and molar volumes. The separation performance of the composite membrane coated by 10 wt% PFPE exhibits rejections of >90% to orange II sodium salt (MW= 350.32 g·mol^-1) and remazol brilliant blue (MW= 626.54 g·mol^-1) in isopropanol. 7-day tests are also conducted to (1) separate tetracycline from ethanol/tetracycline solutions and (2) recover hexane from hexane/-carotene solutions. The fluxes and rejections of both membranes do not fluctuate significantly during 7-day continuous tests with performance comparable with and superior to most literature data. Therefore, the PFPE coated membranes may have great potential to be the next-generation OSN membranes for industrial applications.