Search Results

You are looking at 1 - 4 of 4 items for :

  • "niobium pentoxide" x
  • Refine by Access: All Content x
Clear All

Abstract  

Nb2O5 supported on SiO2-Al2O3 were prepared with a wide loading range (2, 5, 10, 15, 20 and 25 mass%) and analyzed by simultaneous thermogravimetric (TG) and differential thermal analysis (DTA). The materials presented a phase transition close to 1364°C. This phase transition was studied by XRD, FTIR and Raman spectroscopy. Amixture of orthorhombic (T) andmonoclinic (H andM) crystalline phases was evidenced in the supported samples, which is coverage dependent, in contrast to the formation of only the monoclinic phase (H and M) when pure Nb2O5 is heated under the same conditions. These results indicate the stabilization of Nb2O5 on silica-alumina surface.

Restricted access

Abstract  

The interactions between titanium dioxide, niobium pentoxide and tantalum pentoxide and 55 elements have been studied by batch experiments in nitric acid. The variation of the distribution ccefficients with nitric acid concentration is presented and discussed. The adsorption mechanism for some ions has also been investigated. Column experiments have been carried out to check the practical use of the investigated oxides in radiochemical separations. A99mTc generator based on the use of TiO2 is also presented.

Restricted access

were tested. Active carbon was rinsed with water, butanol, dimethyl sulfoxide and water before use. High-surface MgO was prepared from low-surface MgO powder by the hydration-calcination treatment [ 11 ]. Calcination of niobium pentoxide hydrate was

Restricted access

5 as the final decompositional product suggesting these to be potential precursors of niobium pentoxide. The kinetic and thermodynamic parameters have been computed from TG data using Coats–Redfern equation. Mala Sharma is

Restricted access