Evaluation of Ag-TiO2 nanocomposite antimicrobial efficacy against bacterial contamination in university hostel water systems

Silver-doped titania nanoparticles (Ag-TiO 2 NPs) were synthesized via liquid impregnation and tested for antimicrobial activity on borehole water from Alex Ekwueme Federal University, Ndufu-Alike (AEFUNAI). Characterization (SEM–EDX, nitrogen adsorption-desorption, XRD, BET, FTIR) showed spongy, slit-shaped particles (35 nm) with high surface area (285.35 ± 103.90 cm 2/g), mesoporosity (type IV with H 3/H 4 hysteresis), and crystalline anatase phases (26–31 nm) retained after Ag doping. FTIR revealed a 1345.6 cm -1 peak, confirming Ag +–TiO 2 lattice bonding. Seven bacterial genera, including E. coli, Salmonella spp., Bacillus spp., Klebsiella spp., Shigella spp., Staphylococcus aureus, and Proteus spp., were found in untreated samples. Treatment with 4 g NPs per 250 ml achieved 99.99 % removal, leaving only Bacillus spp. Agar diffusion showed inhibition zones (mm): E. coli > Proteus spp. > S. aureus > Salmonella spp. > Shigella spp. > Klebsiella spp. > Bacillus spp. Ag-TiO 2 NPs demonstrated strong potential for borehole water disinfection.