Mesoporous silica coated magnetic nanoparticle for radioactive nuclides separation in solution

Abstract

Radioactive cesium well known as representative radioactive nuclide should be restricted because of its high radioactivity (through the emission of gamma rays), long half-life (30 years) and cause severe harm to human health and organism. Methods involving solvent extraction, precipitation and adsorption have been used for capturing hazardous cesium. Among them, adsorption is reported to a better method due to high selectivity, rapid separation, high thermal, and radiation stabilities. Recently, various substrates functionalized with metal ferrocyanide show exceptional adsorption capacity towards radio-cesium. Among them, functionalized mesoporous silica-coated magnetic nanoparticle is well separated, but precipitated, and has low capacity due to their size of hundred-nanometer scale. In this study, magnetic iron oxide nanoparticles (MNPs) embedded in functionalized mesoporous silica have been synthesized for high surface area for high capacity, and easy magnetic separation. Because surface area and magnetic separation are related to the thickness of silica and the size of magnetic nanoparticle respectively, the thickness of silica and the size of magnetic nanoparticle is controlled. 12nm, 30nm, 42nm of MNP is obtained using a thermal decomposition method. These nanoparticles are then phase transferred and surface area enhanced with a mesoporous silica coating. The mesoporous silica-coated MNP is functionalized with metal ferrocyanide for capturing radioactive cesium. The pore structure disappears after functionalization, to maintain the pore structure after functionalization, the organic solvent is added in synthesis to increase pore size. This study means this functionalized mesoporous silica-coated magnetic nanoparticle used as adsorbent which is easily separated magnetic and has high capacity using the space of silica the captured radioactive cesium in a functionalized nanoparticle can be separated easily from water by using a strong magnet.