Sustainable synthesis of silver nanoparticles using Cynometra ramiflora leaf extract for methyl orange degradation
Raja Selvaraj, Stuthi A. Shetty, Gokulakrishnan Murugesan, Thivaharan Varadavenkatesan, Ramesh Vinayagam
Abstract
Abstract This study presents an eco-friendly method to synthesize silver nanoparticles (AgNPs) utilizing the leaf extract of Cynometra ramiflora as a bio-reducing agent. A distinct 431 nm surface plasmon resonance signal confirmed the formation of AgNPs. SEM images portrayed uniformly distributed spherical nanoparticles with smooth surfaces. EDX analysis showed a prominent peak at 3 keV, confirming elemental silver. TEM analysis indicated that most AgNPs were 10–25 nm in size, with a mean size of 18.84 nm. XRD confirmed the face-centered cubic nature of the AgNPs. The d-spacing for the (111) plane was found to be 0.2287 nm, in agreement with standard reference values. FTIR analysis demonstrated signals at 3301, 1637, and 843 cm −1 , indicating the engagement of functional moieties in reducing and capping the AgNPs. The synthesized AgNPs had a high zeta potential (− 18.2 mV), revealing good stability. The AgNPs demonstrated excellent catalytic potential in the presence of NaBH 4 , degrading approximately 95% of methyl orange dye within 15 min, following a pseudo-first-order kinetic model with a kinetic constant of 0.186 min −1 .