Mofs-Mediated Nanoscale Turing Structure in Polyamide Membrane for Enhanced Nanofiltration

This work reported the new type of Turing-structured nano-polyamide membrane was prepared successfully. By introducing polyvinylpyrrolidone (PVP) into UiO-66-NH2,Zr-MOFs (PVP-UiO-66-NH2) with high water hydrophilicity and low particle size were 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 technology. Thanks to the swelling of PVP in the aqueous phase, the diffusion of amine monomer reduced, and the local concentration of amine monomer increased through hydrogen bonding between carbonyl in PVP and amino in amine monomer, which induced local interface reaction and helped to generate uniform nano Turing structure. The successful loading and uniform distribution of PVP-UiO-66-NH2 in the membranes has been proved by experiments, and the membranes were used for water and salt separation. Compared with the pure polyamide membrane showing the pure water permeability of 17.56 L∙M∙H∙bar -1 and the Na2SO4 removal rate of 99.56%, the membrane introduced PVP-UiO-66-NH2 at a concentration of 0.02 g/L displayed a higher permeability of 32.95 L∙M∙H∙bar -1 and stable Na2SO4 removal rate of 99.35%. In addition, experiments showed that the obtained PVP-UiO-66-NH2 @ polyamide composite membrane had good stability and heat resistance