Hydrothermal synthesis and sorption performance to Cs(I) and Sr(II) of zirconia-analcime composites derived from coal fly ash cenospheres

• DOI: 10.15826/chimtech.2022.9.4.18
• Publication Date: 2022-11-11T05:52:26Z
• Authors: Tatiana A. Veresh...; Ekaterina A. Kuti...; Olga V. Buyko; Alexander G. Anshits
• Keywords: CS(I) AND SR(II) SORPTION; cs(i) and sr(ii) sorption; cenospheres; CENOSPHERES; 02 engineering and technology; HYDROTHERMAL SYNTHESIS; hydrothermal synthesis; Chemistry; RADIOACTIVE WASTE; cenospheres; hydrothermal synthesis; zirconia-analcime composite; Cs(I) and Sr(II) sorption; radioactive waste; ZIRCONIA-ANALCIME COMPOSITE; radioactive waste; 0210 nano-technology; QD1-999; zirconia-analcime composite

The paper is concerned with (i) the hydrothermal synthesis of hydrous zirconium dioxide (HZD) bearing analcime (HZD-ANA, zirconia-analcime) and (ii) its sorption properties with respect to Cs+ and Sr2+. The HZD-ANA particles were synthesized from coal fly ash cenospheres composed of aluminosilicate glass with (SiO2/Al2O3)wt.=3.1 and characterized by PXRD, SEM-EDS, STA, and low-temperature N2 adsorption. The non-radioactive simulant solutions of different acidity (pH=2–10) and Cs+/Sr2+ content (0.5–50.0 mg/L) were used in the work. The effect of synthesis conditions on the HZD-ANA particle size, zirconia content and localization as well as the sorption behavior with respect to Cs+ and Sr2+ (capacity, KD) were clarified. It was found that the small-sized HZD-ANA composites surpasses the Zr free analcime and large-sized HZD-ANA material in the Cs+ and Sr2+ sorption parameters (KD ~104–106 mL/g). The conditions to synthesize the zirconia-analcime composite of the highly enhanced sorption ability with respect to Sr2+ (KD ~106 mL/g) were determined. The high-temperature solid-phase re-crystallization of Cs+/Sr2+-exchanged HZD-ANA composites was shown to occur at 1000 °C resulting in a polyphase system based on nepheline, tetragonal ZrO2, and glass phase.