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    Development of BaO-containing radiation-shielding glass using natural dolomite as a raw-material component
    (2027-01-01)
    Cheewasukhanont, W.
    ;
    Kothan, S.
    ;
    Tungjai, M.
    ;
    Intachai, N.
    ;
    Ruangtaweep, Y.
    This study investigates the incorporation of dolomite (CaMg(CO<inf>3</inf>)<inf>2</inf>) as a natural substitute for synthetic CaO in the fabrication of radiation shielding glass (RSG). Dolomite samples from Kanchanaburi, Thailand, were characterized using X-ray fluorescence (XRF) to determine their chemical composition, revealing CaO (76.59-79.84 wt%) and MgO (19.13-21.54 wt%) as the primary components. These dolomites were used to synthesize borosilicate-based host glasses, where density remained stable (∼2.5 g/cm<sup>3</sup>), ensuring structural integrity. Optical transmittance measurements showed an average 80% transparency in the visible range. To enhance radiation attenuation, BaO was incorporated into the glass matrix at varying concentrations (5-35 mol%). Increasing BaO content increased the density of the glass samples, which contributed to improved radiation attenuation performance. The radiation-shielding properties, predicted using WinXCom over a wide photon energy range and experimentally evaluated at 0.662 MeV, improved with increasing BaO content. The HVL, Pb-equivalent thickness, and EABF results further supported the enhanced attenuation performance of the developed glasses, indicating that higher BaO content reduced the contribution of scattered photons to absorbed energy buildup in the intermediate-energy region. In addition, preliminary glass-forming tests of the B4 composition demonstrated the feasibility of preparing a larger glass sheet under similar melting and annealing conditions, although further optimization is still required. These findings suggest that natural dolomite can serve as a useful raw-material component for developing BaO-containing radiation-shielding glass with balanced optical transparency, density, and attenuation performance.
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    A novel photocatalyst of Y2O3-BaO-ZnO ternary system for enhanced photocatalytic degradation of carbofuran insecticide
    (2024-08-01)
    Sujinnapram, Supphadate
    ;
    Krobthong, Sucheewan
    ;
    Moungsrijun, Sasimonton
    ;
    Boonruang, Chatdanai
    ;
    Kaewtrakulchai, Napat
    A novel Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system was synthesized via precipitation of a mixture of Y(NO<inf>3</inf>)<inf>3</inf>.6 H<inf>2</inf>O:Ba(NO<inf>3</inf>)<inf>2</inf>:Zn(NO<inf>3</inf>)<inf>2</inf>.6 H<inf>2</inf>O using some Fibonacci sequences. The Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO was applied to the photocatalyst to investigate the degradation of carbofuran insecticide. The Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO prepared at the sequence ratio of 5:8:13 (YBZ5) exhibited the highest photocatalytic performance. Morphological characterization showed that the particle size of the YBZ5 sample was significantly smaller than that of ZnO by over half, possibly providing high surface areas. The crystalline structure, functional group, and surface chemical composition investigations confirmed the presence of Y<inf>2</inf>O<inf>3</inf>, BaO, and ZnO. The fluorescence study exhibited no difference. Based on band gap energy and energy band alignment analysis, the Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system demonstrated a well-aligned valence band. The energy band alignment analysis revealed a good alignment of the valence band for continuous hole transport in the Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system. The alignment induces charge separation which reduces recombination and provides efficient active carriers at the surfaces of the photocatalyst, allowing reactions with toxic molecules. Therefore, the synergistic function of high surface areas and appropriate energy band alignments of the novel Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system is considered the crucial factor in the enhancement of photocatalytic performance.