Ultrafiltration system of an MFI-type zeolite-coated membrane in N,N-dimethylformamide solvent

Abstract

Resistance to polar organic solvents is a desirable characteristic of membranes which needs further development for membrane separation systems. Inorganic membranes are one type of material with the potential to confer the desired resistance. In the present work, an MFI-type zeolite-coated tubular membrane was therefore prepared and evaluated for application to an ultrafiltration system using a polar organic solvent. The membrane was successfully prepared by a secondary growth method on an α-alumina membrane continuously with thickness of ca. 100 µm. The ultrafiltration of gold nanoparticles, as a model solute, in N,N-dimethylformamide (DMF) was achieved by the membrane under investigation, although the pure DMF permeability was 1.56 ( ± 0.41) × 10−7 m3/m2·s·MPa which is lower than conventional polymeric nanofiltration membranes. Real rejection of the gold nanoparticles was calculated based on concentration polarization model and was obtained as 1.00. The MFI-type zeolite-coated membrane maintained a stable effective rejection level over a long-term operation of 80 h, which indicates that the membrane possesses sufficient resistance to polar organic solvents.