A thin-film nanocomposite nanofiltration membrane prepared on a support with in situ embedded zeolite nanoparticles

Abstract

A novel approach to fabricating thin-film nanocomposite (TFN) nanofiltration membranes was reported in this study. It involved the preparation of a polysulfone support in situ embedded with zeolite nanoparticles followed by interfacial polymerization to form the polyamide layer. Compared with the TFN membranes prepared by the conventional method (TFN-C), the new TFN membrane (TFN-I) had higher loading and more uniform dispersion of nanoparticles in the polyamide layer. The nanoparticles incorporation resulted in an increase of surface roughness but no change of surface hydrophilicity. The TFN-I membrane doubled the water permeability compared with the control membrane (TFC). The TFN-I membrane had a similar rejection of MgSO4 (>93% at 150 psi) and negatively charged pharmaceuticals (PhACs) with TFC, but a reduced rejection of NaCl and a slightly lower rejection of neutral and positively charged PhACs of small molecular weights. The TFN-I membrane performed much better than the TFN-C membrane. The demonstrated performance of TFN-I could be due to the internal pores of zeolite nanoparticles, the increased membrane surface roughness and, though undesirable, the microporous defects between the nanoparticles and the polyamide matrix. The newly developed approach is highly promising for the fabrication of TFN nanofiltration and reverse osmosis membranes of improved performance by incorporating various nanoparticles.