Scaling up green synthesis of silver nanoparticles and their immobilization for water disinfection in a “Point of Use” fixed bed unit

Abstract

In the current study, the scale-up effect on the characteristics and water disinfection activity of silver nanoparticles (AgNPs) synthesized by a green synthesis method using the teak leaves extract in an agitated tank system, while scaling up from a base scale of 0.5 L to larger scales of 1 L and 5 L, is investigated. Four different scale-up criteria (constant power output (P/V), constant impeller pump rate (Q/V), constant maximum impeller speed, and constant impeller Reynolds number) were applied for scaling up, while maintaining the geometric similarity. The criterion of constant P/V resulted in disinfection potential and average particle sizes closer to those in the base scale and thus considered as the best scale-up criterion for the teak leaf extract-mediated AgNPs synthesis. The performance of the “Point of Use” fixed-bed water disinfection unit, consisting of a packed bed of Granular Activated Carbon (GAC) immobilized with AgNPs synthesized on a large scale (which was scaled up with the constant P/V criterion), was evaluated. The disinfection unit could successfully produce drinking water without losing the disinfection activity even after multiple uses. © 2025 Elsevier Ltd.