Superparamagnetically modified A-type, X-type and CHA-type zeolites with silica-coated FeO and CoFeO nanoparticles for removal of Sr and Cs from radioactively contaminated water

Ito, Azusa  ; Thirunavukkarasu, G.*; Hriljac, J. A.*

Magnetised zeolite A, zeolite X and Na,K-CHA composites with superparamagnetic nanoparticles of SiO-coated FeO or CoFeO ferrite spinels were prepared, characterised and tested for ion exchange efficacy. They were synthesised by following three steps, synthesising FeO and CoFeO nanoparticles by a solvothermal method, coating the metal oxide particles with SiO by a sol-gel process, and attaching the MO/SiO onto the zeolites during synthesis. The magnetic zeolites were characterised by X-ray diffraction, X-ray fluorescence spectroscopy, Raman spectroscopy, vibrating sample magnetometry and both scanning and transmission electron microscopy. It was confirmed they had superparamagnetic properties due to successful attachment of the MO/SiO particles onto the zeolites. Adsorption capacities of Sr onto the magnetic zeolite A and zeolite X and Cs onto the magnetic Na,K-CHA were also evaluated. The results show the MO/SiO did not block the adsorption sites of the zeolites and the MO/SiO particles were not detached from the zeolites during the adsorption experiments.