Green Synthesis of Silver Nanoparticles by Using Red Geranium Flower ( Pelargonium graveolens ) for Efficient Photocatalytic Dye Degradation

ABSTRACT

The development of sustainable and environmentally benign strategies for nanoparticle synthesis and wastewater remediation remains a significant challenge. In this study, silver nanoparticles ( g ‐AgNPs) were green synthesized using the aqueous extract of Pelargonium graveolens (red geranium) flowers, which served as both reducing and stabilizing agents, eliminating the need for hazardous chemicals. The synthesized nanoparticles were characterized by UV–vis spectroscopy, PXRD, FTIR, SEM, and EDX analyses. A characteristic surface plasmon resonance band at 424 nm confirmed nanoparticle formation; PXRD revealed a crystalline structure with an average crystallite size of ∼14 nm. SEM analysis showed predominantly spherical nanoparticles with an average particle size of 15.28 ± 2.45 nm. The g ‐AgNPs exhibited excellent visible‐light photocatalytic activity, achieving 94% degradation of methylene blue (MB) following pseudo‐first‐order kinetics with an apparent rate constant of 0.0094 min ^{− 1} . The catalyst retained 95.7% of its degradation efficiency after repeated reuse, demonstrating good stability. Control experiments confirmed that both visible light and g ‐AgNPs were essential for efficient dye degradation. DFT calculations revealed strong MB adsorption on the Ag surface with an adsorption free energy of −96.54 kcal mol ^{− 1} , facilitating charge transfer and enhancing photocatalytic performance. These findings demonstrate the potential of plant‐mediated AgNPs for sustainable environmental remediation.