MOFs-mediated nanoscale Turing structure in polyamide membrane for enhanced nanofiltration

Abstract

This work reported the successful preparation of a novel nano-Turing structure polyamide membrane. By introducing polyvinylpyrrolidone (PVP) into UiO-66-NH2, PVP-UiO-66-NH2 with high water hydrophilicity and low particle size was synthesized. The aqueous phase dispersion containing PVP-UiO-66-NH2 was loaded on the support through vacuum filtration method, and PVP-UiO-66-NH2 was fused in the polyamide layer via traditional interfacial polymerization (IP) technology. The existence of PVP-UiO-66-NH2 induced the occurrence of “local activation and lateral inhibition” in the IP system, resulting in the appearance of nano-Turing structure on the membrane surface. The successful preparation of PVP-UiO-66-NH2@polyamide composite membrane with uniform distribution of PVP-UiO-66-NH2 was proved. The PVP-UiO-66-NH2@polyamide composite membrane showed excellent water permeability of 32.95 L·m−2·h−1·bar−1 and stable Na2SO4 removal rate of 99.35 %, compared with 17.56 L·m−2·h−1·bar−1 and 99.56 % of pure polyamide membrane under the same conditions. In addition, the PVP-UiO-66-NH2@polyamide composite membrane exhibited excellent long-term filtration stability, thermal stability and antibacterial property.