Fabrication of Ag2S-incorporated polyamide thin film nanocomposite reverse osmosis membranes with antifouling properties

Abstract

Herein we report on the fabrication of polyamide (PA) thin-film composites (TFC) as reverse osmosis (RO) membranes with embedded silver sulfide (Ag2S) nanoparticles (NPs) to form thin-film nanocomposites (TFN) and mitigate fouling. The fabrication of TFN membranes was done via interfacial polymerization on a polysulfone support membrane. Varied amounts of Ag2S NPs (20, 30, and 50 mg) were added to the aqueous phase to form membranes with enhanced antifouling and permselectivity performance. The chemical composition, surface topography, resistance to organic fouling and biofouling, water flux, and salt rejection, were tested on all membranes. The formation of Ag2S was confirmed by XRD and transmission electron microscopy. The pure water flux (Jo) obtained by all TFN membranes was above 25 L/m2h. Moreover, the 30 mg loaded TFN membrane attained the highest Jo of 32.7 L/m2h. Salt rejection of the nanocomposite membranes were observed to be above 98%, which deems them suitable materials for desalination. TFN demonstrated resistance to fouling by bovine serum albumin and was able to retard bacterial colony formation. This was attributed to antibacterial properties of Ag2S NPs. Moreover, surface roughness decreased with increased NP loading, which also reduced the propensity of fouling.