Microwave-assisted green synthesis of silver nanoparticles using extract of mint leaves

Abstract

Silver nanoparticles are widely used in areas such as biosensing, hydrogen production, electronics, photovoltaics, antimicrobials, and biomedical engineering applications. Biological synthesis is regarded as a safe and non-toxic process, but its main disadvantage is the slow processing time. The mint leaf extract can act as both a reducing and stabilizing agent for the biological synthesis of silver nanoparticles. In this work, a rapid and green method for the microwave-assisted biological synthesis of silver nanoparticles was investigated using an aqueous leaf extract of mint as a biosource of cost-effective, non-hazardous reducing and stabilizing agents. The optimum conditions for microwave extraction of mint leaves were 220 s at 800 W and a 5 g/L mint-to-water ratio. Meanwhile, the optimal conditions for the biological synthesis of silver nanoparticles were as follows: concentration of silver nitrate solution = 2 mM, microwave reaction time = 100 s at 800 W, and pH = 8. The silver nanoparticles obtained by the microwave heating process showed a surface plasmon band centered at 420 nm with a higher peak height than those prepared by the conventional heating process. Dynamic light scattering analysis has shown the synthesized silver nanoparticles to have an average diameter of 54 nm.