AUTHOR=Ito Azusa , Thirunavukkarasu Gnanavel , Hriljac Joseph A. 

TITLE=Superparamagnetically modified A-type, X-type and CHA-type zeolites with silica-coated Fe3O4 and CoFe2O4 nanoparticles for removal of Sr2+ and Cs+ from radioactively contaminated water

JOURNAL=Frontiers in Environmental Chemistry

VOLUME=5

YEAR=2024

URL=https://www.frontiersin.org/journals/environmental-chemistry/articles/10.3389/fenvc.2024.1445482

DOI=10.3389/fenvc.2024.1445482

ISSN=2673-4486

ABSTRACT=<p>Magnetised zeolite A, zeolite X and Na,K-CHA composites with superparamagnetic nanoparticles of SiO<sub>2</sub>-coated Fe<sub>3</sub>O<sub>4</sub> or CoFe<sub>2</sub>O<sub>4</sub> ferrite spinels were prepared, characterised and tested for ion exchange efficacy. They were synthesised by following three steps, synthesising Fe<sub>3</sub>O<sub>4</sub> and CoFe<sub>2</sub>O<sub>4</sub> nanoparticles by a solvothermal method, coating the metal oxide particles with SiO<sub>2</sub> by a sol-gel process, and attaching the M<sub>x</sub>O<sub>y</sub>/SiO<sub>2</sub> 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 M<sub>x</sub>O<sub>y</sub>/SiO<sub>2</sub> particles onto the zeolites. Adsorption capacities of Sr<sup>2+</sup> onto the magnetic zeolite A and zeolite X and Cs<sup>+</sup> onto the magnetic Na,K-CHA were also evaluated. The results show the M<sub>x</sub>O<sub>y</sub>/SiO<sub>2</sub> did not block the adsorption sites of the zeolites and the M<sub>x</sub>O<sub>y</sub>/SiO<sub>2</sub> particles were not detached from the zeolites during the adsorption experiments.</p>