Adsorptive performance of green synthesized zinc oxide nanoparticles for the removal of cadmium (II) and lead (II) ions

Abstract This study has Zinc oxide (ZnO) nanoparticles (NPs) synthesized from the leaf extract of Costus Afers via a green approach. The zinc nanoparticle (ZnO NPs) showed excellent adsorption capabilities towards Cd (II) and Pb ions. ZnO NPs were characterized by Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD). formation was confirmed absorption band at 825cm −1 747cm . XRD SEM analysis show high purity hexagonal structure with crystallite size 83.56 nm. A batch experiment employed to examine process parameters such as effect initial pH solution, metal ion concentration, adsorbent mass, contact time on sequestration efficiency equilibrium isotherm models studied using Langmuir, Freundlich, Temkin, Dubinin-Radushkevich models. Langmuir provided best fit for coefficient determination (R 2 ) values 0.988 0.986 cadmium lead ions respectively, indicating monolayer surface ZnONPs. pseudo-second-order kinetics model presented good giving correlation 0.989 0.996 suggesting that chemisorptions are rate-determining step.