Green Synthesis of Fe3O4 Nanoparticles Using Eucalyptus Globules Leaf Extract and Its Application for Phosphate Removal from Synthetic Wastewater

Abstract

Phosphorus concentrations typically are low in natural waters, but it is required in relatively large amounts by plants. Phosphorus is generally the most important nutrient controlling plant growth in aquatic ecosystems, and also phosphorus pollution of natural waters is considered a primary cause of eutrophication. In this research work, EGLE coated magnetite nanoparticles at volume ratio of 2:1, 1:1, and 1:2 were synthesized with the same method by varying the proportion of precursor and EGLE in presence of NaOH by co- precipitation process. The synthesized NPs were characterized by using TGA, XRD, FTIR, DRS, and SEM analysis. The characterized nanoparticles were used for the removal of phosphate from aqueous solution by adsorption mechanism and all the adsorption experiments were carried out in batch mode. The effects of the contact time, dose of the adsorbent, pH, and initial phosphate concentration on the adsorption capacity were studied. The crystal size of the synthesized NPs calculated by Debye-Scherer equation were 10.7 nm, 14.34 nm and 14.79 nm for 2:1, 1:1 and 1:2 NPs respectively. The band gap energy of synthesized NPs was found to be 2.19 eV, 1.92 eV and 1.89 eV for 2:1, 1:1 and 1:2 NPs respectively. The results showed that the adsorption capacity for the phosphate increased by increasing the contact time, adsorbent dose at pH=6 of the solution. The adsorption kinetics was in good agreement with pseudo 2nd order kinetic equation and the adsorption isotherm showed good fitting to Freundlich isotherm. The phosphate removal efficiency of 2:1, 1:1 and 1:2 Fe3O4-EGLE NPs were 98.97%, 97.32% and 97.50%, respectively. The results suggested that the biosynthesized Fe3O4 nanoparticles using EGLE displayed a definitive potential for phosphate removal from synthetic wastewater