New approach for drinking water disinfection and purification using silver nano particles/activated carbon composite

Abstract A novel eco-friendly filtration system was developed and evaluated for its efficiency in disinfecting and purifying raw drinking water. The system is based on combining biosynthesized silver nanoparticles–activated carbon in a single nanocomposite, (biosynthesized using olive leaf extract as a green reducing and stabilizing agent), applied in a specially designed filtration unit. The nanocomposite, consisting of spherical particles ranging from 6.54 to 61.68 nm, was prepared under optimized conditions and characterized using multiple techniques including UV-Vis spectroscopy, FT-IR, XRD, SEM, and TEM. Raw water samples collected from Sharky Drinking Water Plant in Alexandria, Egypt were analyzed before and after treatment to assess physicochemical and microbiological quality. The optimized system, modified with 1.0 mg of the nanocomposite, demonstrated outstanding performance, achieving removal efficiencies of 94.5% for total algal count, 98.5% for total bacterial count, and more than 99.4% for total coliforms. Additionally, the system achieved high removal rates of turbidity (92%), ammonia (98.3%), nitrite (95.4%), and a moderate removal of nitrate (29.2%), with all residual levels falling within acceptable drinking water standards, except for total algae, which was slightly higher. Compared to conventional coagulation–chlorination treatment, the proposed system exhibited superior removal efficiency, faster flow rate (up to 1000 mL/min), and significant reductions in chemical use, sludge generation, and disinfection by-products. This study highlights the potential of integrating silver’s antimicrobial potency with the adsorption capacity of activated carbon in a sustainable, cost-effective, and scalable water treatment system. The novelty lies in offering a green and efficient alternative to traditional treatment methods, with the flexibility to function as a standalone purification unit or as a replacement for primary disinfection steps.