Tomoyo Goto

We investigated the crystal growth of hydroxyapatite (HAp) from α-phase (α-TCP) and β-phase (β-TCP) tricalcium phosphates showing different solubility, under hydrothermal conditions. Samples of α-TCP and β-TCP were treated up to 72 h under hydrothermal conditions at 120°C. The α-TCP sample was completely transformed into HAp crystals within 1 h after the powder was exposed to hydrothermal conditions. In contrast, the β-TCP sample required more than 72 h to achieve complete transformation into HA

The CO sensing properties of a micro thermoelectric gas sensor (micro-TGS) with a double AuPtPd/SnO₂ and Pt/α-Al₂O₃ catalyst were investigated. While several nanometer sized Pt and Pd particles were uniformly dispersed on SnO₂, the Au particles were aggregated as particles measuring >10 nm in diameter. In situ diffuse reflectance Fourier transform Infrared spectroscopy (DRIFT) analysis of the catalyst showed a CO adsorption peak on Pt and Pd, but no clear peak corresponding to the interaction be

Titania nanotubes (TNTs) have nanometer-sized tubular morphologies with layered structures. TNTs are candidate sorbents for the removal of many heavy metals and radionuclides. In this study, we investigated the Cs+ sorption capacity of TNTs synthesized by a solution chemical method in comparison with those of zeolite and TiO2 particles. The TNT powder was shaken in 0.2–4.0 mM CsCl aqueous solution at 10, 25, and 40°C for up to 7 days. The sorption tests showed that the sorption density of Cs+ pe

Layered sodium titanate is a typical ion-exchanger for water purification aimed at removing cationic heavy metals and radionuclides. The material design of an ion-exchanger is effective for cation removal. For that purpose, understanding the basic impacts of crystallographic properties such as crystal size, morphology, and phase is critical for developing highly functional nanoscale ion-exchangers. In this study, we investigate the principal relationship between the crystallographic properties o

In this study, we synthesized the TiO 2 -modified hydroxyapatite (HAp) with various morphologies by hydrothermal treatment using urea decomposition, at 160 oC for 6 h. After hydrothermal treatment, carbonate-substituted HAp and TiO 2 (anatase) phases were formed in products using 1.0-0.1 M urea solution. The morphology of synthesized HAp changed from small plate-shaped to long needle-shaped crystals with decreasing the urea concentration. The photocatalytic property for samples was investigated