Synthesis and characterization of magnetite nanoparticles from polyol medium for sorption and selective separation of Pd(II) from aqueous solution

Abstract

Magnetite nanoparticles were synthesized by reverse co-precipitation method using iron salts in alkaline medium, in presence of ethylene glycol (EG) or diethylene glycol (DEG) as polyol solvents. The morphology and magnetic properties of pure magnetite and modified magnetite were characterized by different techniques. X-ray diffraction (XRD) studies support the presence of a highly crystalline Fe3O4 phase and the coating of DEG or EG did not affect the composition of magnetite. Transmission electron microscopy (TEM) image showed that the shape of Fe3O4, DEG coated particles and EG coated particles were spherical with a nano size of mean diameter 18.8, 14.45 and 10.49 nm, respectively. The usability of EG-coated magnetite for the sorption of Pd(II) from aqueous chloride solution was investigated by batch experiments. Parameters affecting the uptake of palladium metal ion were studied. The kinetic studies and the isotherm data were described using different models. Experimental data showed that the sorption process could be quite fitted with pseudo-second order kinetic and Langmuir models. In addition, thermodynamic parameters were evaluated to expect the nature of sorption. Further, the desorption of Pd(II) from EG/MNPs was achieved using 5.0 mol/L HNO3 solution, and the nano-magnetite was reused effectively. Finally, the separation possibility of palladium from some fission products was achieved successfully.