In Situ Silver Decoration on Graphene Oxide-Treated Thin Film Composite Forward Osmosis Membranes: Biocidal Properties and Regeneration Potential

The surfaces of thin film composite (TFC) forward osmosis (FO) membranes were modified by in situ formation of silver nanoparticles (AgNPs) in the presence and absence of graphene oxide (GO) nanosheets to impart biocidal properties to the membranes. The abundance of oxygen-containing functional groups in GO makes it suitable for anchoring Ag⁺ ions and governing the size, shape, and distribution of AgNPs. The presence of GO resulted in the formation of smaller and uniformly distributed AgNPs as well as increased silver loading, higher stability, and enhanced ion release control. Membranes modified by both GO and Ag exhibited improved (98%) bacterial inactivation when compared to that of only Ag-modified (80%) or GO-modified membranes (50%). After release of Ag ion from GO-Ag-modified membranes for 7 days, AgNP regeneration was conducted in a manner identical to the in situ Ag formation procedure. After regeneration, the membrane regained nearly all of its antibacterial properties and 75% of its initial silver loading.