Fabrication of well-defined electromagnetic Fe3O4/polyaniline hollow microspheres and their application in Pb2+ uptake

Abstract

Well-defined superparamagnetic and conductive Fe₃O₄/polyaniline (PANI) hollow spheres were fabricated using positively charged polystyrene (PS) spheres as templates. The negatively charged Fe₃O₄ particles, which were decorated by citric acid, can be attached onto the surface of the PS spheres via electrostatic interaction. Subsequently, the PANI layer was coated onto the PS/Fe₃O₄ templates by in situ chemical oxidative polymerization. Finally, removal of the PS core by dissolving with tetrahydrofuran provided the electromagnetic hollow spheres. Morphologies and compositions of Fe₃O₄/PANI hollow spheres were investigated by using SEM, TEM, FTIR and XRD. Magnetic analysis demonstrates that the synthesized composite spheres possess the characteristic of superparamagnetism and the saturation magnetization value is 26.2 emu g⁻¹. Batch adsorption shows that the Fe₃O₄/PANI hollow spheres exhibit high uptake property of Pb²⁺ in aqueous solution. The adsorption kinetics follows the mechanism of pseudo-second-order kinetics and the sorption agrees well with the Langmuir isotherm.