Comparative Adsorption Study of Methylene Blue Dye Using Green and Chemically Synthesized Silver Nanoparticles

The present study explores the synthesis of silver nanoparticles (AgNPs) using both green and chemical methods and evaluates their efficacy in the adsorptive removal of methylene blue (MB) dye from aqueous solutions. Green synthesis was carried out using bio-waste plant extract, while the chemical synthesis employed a conventional reduction approach. The synthesized nanoparticles were extensively characterized using UV-Vis spectroscopy, DLS, XRD, and FTIR to confirm their structural, morphological, and functional properties. The adsorption potential of AgNPs was assessed by varying parameters such as adsorbent dosage, initial dye concentration, pH, and contact time. Results demonstrated that over 95% MB removal was achieved within 60 minutes under visible light irradiation. The adsorption data closely followed the Langmuir isotherm model, indicating monolayer adsorption, and the kinetics were well-fitted to the pseudo-first-order model. Additionally, reusability studies confirmed the sustained efficiency of AgNPs over multiple cycles, highlighting their cost-effectiveness. Toxicity studies on bacterial and fungal strains revealed that green-synthesized AgNPs exhibited better biocompatibility, whereas chemically synthesized AgNPs displayed higher antimicrobial properties. Seed germination tests further demonstrated the environmental safety of plant-derived AgNPs. The study provides critical insights into the comparative performance of green and chemically synthesized AgNPs for dye removal applications, with the green synthesis approach offering a sustainable and eco-friendly alternative. The findings suggest that AgNPs, particularly those synthesized via green methods, hold significant potential for wastewater treatment applications.