(366aj) Characterization of the Metal-Organic Frameworks and Polyamide Interfaces in Membranes for Water Treatment and Antibacterial Applications

• Membrane Separations
• Electrochemistry
• MOF
• Desalination
• Nanotechnology

Abstract

The integration of biocidal nanoparticles into PA membranes holds promise for enhancing their resistance to biofouling. However, the choice of incorporation techniques can be leveraged to tailor the properties of TFN membranes for specific water purification applications. In this study, Ag-MOFs were incorporated into PA membranes using three different methods: (i) incorporated polymerization, (ii) dip-coating, and (iii) in-situ ultrasonic techniques. All modified TFN membranes proved to be effective in biofouling mitigation, each presenting unique morphology and surface characteristics suitable for diverse water purification applications. For example, the in-situ ultrasonic interlayered Ag-MOFs, represented by the M1 membrane, featured the largest pores (with a diameter of 14.13 Å) and a thin, smooth PA layer, making it the top-performing membrane in terms of water permeance (water flux of 82.0 LMH) among all fabricated membranes. It also demonstrated superior anti-fouling and anti-biofouling performance, achieving an FRR (%) of 94.1 in both filtration tests. On the other hand, the M4 membrane (with surface-grafted dip-coated Ag-MOFs) exhibited the highest salt rejection performance compared to other TFN membranes, attributed to its highly negatively charged surface and a compact PA network with extremely narrow pores (d_p=10.06 Å). Additionally, the incorporated polymerization technique yielded a highly hydrophilic membrane (M3), enabling an improved water flux of 66.8 LMH compared to the pristine PA membrane (50.9 LMH). M3 membrane also obtained the lowest FRR in fouling (83.9) and biofouling (80.7%) filtration tests, primarily attributed to its elevated surface roughness (Ra = 72.8 nm).