Thin-Film Nanocomposite Forward Osmosis Membranes Prepared on PVC Substrates with Polydopamine Functionalized Zr-Based Metal Organic Frameworks

Abstract

In this study, UiO-66-NH2 metal–organic frameworks (MOFs) were modified by a mussel-inspired approach to yield polydopamine (PDA)–MOF hybrid nanoparticles (NPs) and then embedded within a polyamide (PA) layer to synthesize thin-film nanocomposite (TFN) membranes for desalination and heavy metal removal. The PA layer was fabricated via interfacial polymerization (IP) reaction between PDA/m-phenylenediamine (MPD) aqueous solution and trimesoyl chloride (TMC)/MOF organic solution on the low-cost PVC substrate. First, various zirconium-based MOFs (Zr-based MOFs) were synthesized with manipulating the dopamine (DA) concentration. Then, after selecting the best NPs (MOF@PDA(0.25)), the effects of different loadings of the selected NPs on the FO performance were evaluated. In comparison to the conventional thin film composite (TFC) membrane (15.95 L/m2 h) using DI water as a feed solution (FS) and 1 M NaCl as a draw solution (DS), incorporation of MOF@PDA(0.25) led to enhanced water flux of the TFN membrane (29.73 L/m2 h) without sacrificing selectivity due to the establishment of extra water channels and improvements in both hydrophilicity and compatibility between NPs and the PA layer. Finally, the modified membranes demonstrated outstanding performance for desalination and heavy metal (Cu2+ and Pb2+) removal. The rejection displayed the trend of Cu2+ > Pb2+ for all of the fabricated membranes.

Metal/covalent–organic framework based thin film nanocomposite membranes for advanced separations

“…DA offers three functions in this process: (1) self-polymerization into PDA to optimize the surface properties of the membrane support; (2) reacting with the MOFs and anchoring them to the membrane support, thereby improving their loading efficacy, dispersibility, and stability within the PA layer; (3) enhancing the compatibility between the polymer matrix and the MOFs. 135 He et al 136 introduced an adhesive PDA coating layer into the surface of a membrane support through co-deposition of PDA and MPD, which provided strong adsorption sites for subsequently added MOF nanocrystals. The chemical reactions involved in such a process included an IP reaction between MPD and TMC molecules, the reaction of the –NH 2 of PDA with the acyl chlorides of TMC, and the reaction between MOF-801 and PDA (Fig.…”

Metal–organic frameworks on versatile substrates

“…354 and 355. Furthermore, other polymers have also been studied, such as rubber, 356 polydopamine, 357,358 acrylic acid, 359,360 polytetrafluoroethylene (PTFE), 361,362 cyclic olefin copolymer (COC), 363 polyvinyl alcohol (PVA), 364 GCE and polylactic acid (PLA), 365 polypropylene, 366,367 polyvinyl chloride, 368 poly (sodium 4-styrenesulfonate), 369 poly(MMA- co -EDMA) membranes, methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EDMA), 370 polyurethane, 371 polyethylenimine, 372 and aerogels. 373…”