Separation of selenite from inorganic selenium ions using TiO2 magnetic nanoparticles

Abstract

A simple and quick separation technique for selenite in natural water was developed using TiO2@SiO2/Fe3O4 nanoparticles. For the synthesis of nanoparticles, a polymer-assisted sol-gel method using hydroxypropyl cellulose (HPC) was developed to control particle dispersion in the synthetic procedure. In addition, titanium butoxide (TBT) precursor, instead of the typical titanium tetra isopropoxide, was used for the formation of the TiO2 shell. The synthesized nanoparticles were used to separate selenite (Se4+) in the presence of Se6+ or selenium anions for the photocatalytic reduction to Se0 atom on the TiO2 shell, followed by magnetic separation using Fe3O4 nanoparticles. The reduction efficiency of the photocatalytic reaction was 81.4% at a UV power of 6W for 3 h with a dark adsorption of 17.5% to the nanoparticles, as determined by inductively coupled plasma-mass spectrometry (ICP-MS). The developed separation method can be used for the speciation and preconcentration of selenium cations in environmental and biological analysis.