Synthesis Of Magnetic MCM-48 Composites And Adsorption Of Uranyl Ions In Aqueous Phase

Because of their large surface area, adjusted pore size and well-defined surface properties for functionalization, mesoporous silica materials have been emerging as a promising carrier for adsorption and drug delivery. Meanwhile, magnetic nanoparticles have shown potential application value in some kinds of fields including targeted drug delivery, magnetic separation, due to their low toxicity and special magnetic properties. Magnetic nanoparticles will be reunited easily, thus magnetic nanoparticles and mesoporous silica materials would be combined, which can be complementary in function, in other words, magnetic/mesoporous silica nanomaterials have both unique magnetic properties, and have some properties of mesoporous materials, for instance, large surface area, etc. The more details are as follows:Coprecipitation synthesized magnetic nanoparticles of cobalt ferrite have been encapsulated with a layer of ordered mesoporous silica through a simple sol-gel process, then CoFe2O4@MCM-48 nanomaterials were prepared. The characterized results reveal that the magnetic/mesoporous silica composite materials shows monodisperse spherical morphology and have typical ordered mesoporous characteristics including large surface area (1100～1300m2/g), large pore volume (0.85～1.20cm3/g), pore size (2.30-2.90nm) and narrow size distribution (200-400nm). The adsorption of uranyl ion by the magnetic/mesoporous silica composite materials was investigated, the results show that the adsorption of uranyl ion is strongly dependent on solution pH, the adsorption efficiency is as much as 91.16%, and the adsorption capacity is as much as 217.97mg/g.Based on CoFe2O4@MCM-48 nanomaterials obtained successfully, pH value were adjusted by 1M NaOH and HCl in the hydrothermal system, so magnetic/mesoporous silica composite materials containing cavities (CoFe2O4@C-MCM-48) were prepared. The results reveal that the magnetic/mesoporous silica nanomaterial shows typical ordered mesoporous characteristics, has cavities structure and have monodisperse spherical morphology with large surface area (800～1200m2/g), large pore volume (0.75～1.40cm3/g), pore size (2.50～6.20nm) and size distribution (160～360nm). The adsorption of radionuclide in the heavy metal wastewater by the magnetic/mesoporous silica nanomaterial of cavities was investigated, the adsorption efficiency is as much as 96.42%, and the adsorption capacity is as much as 230.45mg/g.