Surface functionalized magnetic α-Fe2O3 nanoparticles: Synthesis, characterization and Hg2+ ion removal in water

Mercury is a specific concern worldwide because of its high toxicity. Exposure to mercury, even at very low concentrations, induces digestive, brain, kidney, neurological and endocrine system diseases. In this work, Fe2O3 nanoparticles were synthesized via one step solution combustion synthesis using glycine as a fuel. The structural features of the as formed Fe2O3 nanoparticles were characterized by XRD, SEM, EDX and FTIR. Further, the surface of the prepared Fe2O3 nanoparticles were coated with silica groups followed by thiol(-SH)functionalization using l-cysteine by ultra-sonication technique. The surface functionalized magnetic nanoparticles were analyzed by FT-IR technique, to confirm the –SH functionalization. The functionalized magnetic nanoparticles of various amounts (0.005 g, 0.010 g. 0.015 g, 0.020 g) were used for removal of Hg2+ ion in 50 ppm aqueous solution. After the adsorption process is over, the Fe2O3@SiO2@SH nanoparticles extracted using strong magnet and the resultant Hg2+ ion in water is studied by complexing with dithizone ligand using UV visible spectroscopic technique. The disappearance of absorbance peak corresponds to [Hg(dithizone)2]2+ at 490 nm, for 50 ppm Hg2+ ion solution when 10 mg of the Fe2O3@SiO2@SH nanoparticles used, confirms that about 98% Hg2+ ion in water is removed.