Facile Epitaxial Growth of Novel Nanoscale Ag-MAFs on Reverse Osmosis Membranes: Enhancing Performance, Antibacterial Activity, and (Bio)fouling Resistance

Journal article, 2025

The increasing demand for advanced thin-film composite (TFC) membranes stems from the limitations of current commercial membranes, particularly their vulnerability to biofouling. In this study, novel silver-based metal-azolate frameworks (Ag-MAFs) were grown insitu on the surface of TFC reverse osmosis (RO) membranes. This functionalization resulted in a 45% increase in permeate flux without compromising salt rejection (97.6%) compared to pristine TFC membranes. The surface functionalization process is rapid, non-destructive, and employs eco-friendly solvents, silver salts, and amino-benzimidazole ligands, enabling repeatable modifications without affecting separation efficiency. The successful integration of Ag-MAFs onto the membrane surface was confirmed through comprehensive chemical characterization, including Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray (EDX) analysis. Notably, Ag-MAFs demonstrated strong stability, with no detectable leaching or detachment after 20 days of continuous water immersion. Morphological analysis using scanning electron microscopy (SEM) and confocal microscopy revealed that Ag-MAFs nanoparticles imparted robust antibacterial activity, reducing live bacterial populations by nearly 99%. Filtration tests showed that Ag-MAFs functionalized membranes exhibited superior fouling resistance and higher water recovery ratios than pristine membranes during a 10 h filtration cycle. This study presents a scalable and reproducible approach for developing advanced antibiofouling TFC membranes capable of long-term operation, eliminating the need for module disassembly and enhancing membrane longevity in practical applications.