Kihumuro, Josephine2026-05-052026-05-052025-11Kihumuro, J. (2025). Performance of green silver Nano particles using Psidium guajava leaves for adsorption of lead from water.Kyambogo University (Unpublished work)https://hdl.handle.net/20.500.12504/2873xiv, 132 p. : col.This research examined the effectiveness of green silver nanoparticles (AgNPs) produced from aqueous extracts of three varieties of Psidium guajava leaves (white, orange, and red fruit mesocarp) in adsorbing lead (Pb²⁺) ions from contaminated water. The study assessed antioxidant activity, characterized nanoparticles, and analysed adsorption performance across different dosages (0.1–1.0 g) and contact durations (5–25 minutes). White guava extract demonstrated the highest antioxidant activity, achieving 83.85% 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging. Additionally, AgNPs from all varieties displayed spherical morphology as observed through Scanning Electron Microscope (SEM), with white guava derived AgNPs exhibiting uniform distribution of the NPs in the matrix. Adsorption experiments demonstrated a maximum Pb²⁺ removal efficiency of 83.16% at a dosage of 0.6 g and a contact time of 20 minutes for white guava AgNPs, while orange and red had 81.53 and 78.35 % respectively. Clay filters infused with AgNPs demonstrated a Pb²⁺ removal efficiency of 99.59% (composite filter), surpassing the performance of unmodified clay, which achieved 91.62% removal. The research findings indicate that white guava derived from AgNPs possess significant antioxidant capacity and adsorption affinity, presenting a viable approach for heavy metal remediation, with prospective applications in point-ofuse water treatment technologies. It is recommended to optimise the ratios of hybrid nanoparticles and conduct field validation in real-world conditions.enLead ions removalSilver nanoparticlesGuava genotypesThesis