Abstract
Removal of radioactive substances, such as cesium (Cs) and strontium (Sr), has become an emerging issue after the Fukushima Daiichi nuclear power plant disaster. It has been reported that hydroxyapatite (HA) and aluminosilicate composite powders can be used to remove Cs and Sr. However, the film type of these materials for the removal of Cs and Sr has not been reported. The aim of this study was to assess the possibility of using HA, aluminosilicate, and aluminosilicate/HA composites for the removal of Cs and Sr radioactive substances. Aluminosilicate films and HA films were fabricated using a sputtering technique with diatomaceous earth and HA targets, respectively. The aluminosilicate film was observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A comb-shaped HA/aluminosilicate composite film was prepared to take advantage of the adsorption properties of the HA and the aluminosilicate films. The Cs and Sr adsorption on these films were also evaluated. In the XRD patterns, the film sputtered from a diatomaceous earth target under 5.0Pa of Ar pressure showed aluminosilicate peaks (Na1.82(Al2Si3O10) and Al2SiO5) after 8h of vapor-phase hydrothermal treatment. The film showed higher adsorption of Cs than Sr in Cs and Sr solutions, while the HA film adsorbed far more Sr than Cs. A HA/aluminosilicate composite film was successfully fabricated, and the SEM images showed that the width of the HA region was 230-260μm, and that of the aluminosilicate region was 170-200μm. The HA/aluminosilicate composite film showed 84.8 ± 11.5% Cs adsorption and 28.3 ± 1.4% Sr adsorption in a mixed solution of Cs and Sr. This study shows the feasibility of using HA films, aluminosilicate films, and HA/aluminosilicate composite films for the removal of radioactive substances such as Cs and Sr.
Published Version
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