Authors: Mariya Josey
Abstract: The present study investigates a green route for the synthesis of silver nanoparticles (AgNPs) using an aqueous leaf extract of Azadirachta indica (neem) and evaluates their catalytic activity in the reduction of methylene blue (MB) in aqueous medium. Fresh neem leaves were washed, chopped, boiled in double-distilled water, filtered, and used as the plant-mediated reducing and capping system. For nanoparticle synthesis, 75 mL of 1 mM silver nitrate solution was mixed with 5 mL of the leaf extract and subjected to microwave irradiation at 800 W and 2450 MHz for 300 s. Formation of AgNPs was indicated by the development of a yellowish-brown to brown colour and was monitored using UV–visible spectroscopy. An absorption band in the region of approximately 408–420 nm was observed and attributed to the surface plasmon resonance (SPR) of silver nanoparticles. The synthesized material was subsequently examined as a nanocatalyst for the NaBH4-assisted reduction of methylene blue. The progress of the reaction was monitored at 664 nm. The original project report indicates that complete reduction occurred within approximately 9 min under one catalyst condition and approximately 15 min when a lower AgNP concentration of 0.011 mg/mL was used, demonstrating that catalyst loading influenced the observed reaction rate. The findings support the usefulness of neem-mediated microwave synthesis as a rapid and comparatively environmentally benign route to AgNPs and indicate their potential for catalytic treatment of dye-containing aqueous systems. Because the original project did not report particle-size measurements, electron microscopy, magnetic characterization, kinetic constants, or statistical testing, these parameters are not inferred in the present article.
