Green Synthesis of ZnO/SnO2 Nanocomposites Using Pine Leaves and Their Application for the Removal of Heavy Metals from Aqueous Media

Abstract

In this study, ZnO/SnO2 nanocomposites were fabricated via a green and simple route using pine tree leaves for the first time. No expensive reagent or hazardous solvent was used for synthesis of nanocomposites and only natural and eco-friendly materials were utilized. ZnO/SnO2 nanocomposites were characterized by XRD, TEM, SEM and EDS. The adsorption performance of ZnO/SnO2 nanocomposites was studied for the efficient removal of Cu2+, Pb2+ and Zn2+ metal ions. To achieve maximum adsorption capacity of metal ions, the influences of several operating conditions including pH value, ZnO/SnO2 nanocomposites dosage, initial concentration of metal ions and contact time were investigated. Also, equilibrium and kinetics models of metal ions to nanocomposites were studied. Adsorption process could be well defined by the Langmuir isotherm with R2 of 0.88, 0.94 and 0.94 for removal of Cu2+, Pb2+ and Zn2+ ions; respectively. The kinetic data fitted the pseudo-second-order model with the R2 value of 0.99, 1 and 0.99 for removal of Cu2+, Pb2+ and Zn2+ ions; respectively.