Strontium adsorption on tantalum-doped hexagonal tungsten oxide

摘要

Hexagonal tungsten oxide (hex-WO_3) has the potential to separate ~(137)Cs and ~(90)Sr from nuclear power plant or fission ~(99)Mo production waste, This study aims to increase the capacity of hex-WO_3 to adsorb Sr~(2+). Ta-doped hex-WO_3 was synthesized by the hydrothermal treatment of sodium tungstate dihydrate and tantalum chloride in concentrated HC1, in the presence of ammonium sulfate. Incorporating Ta into the WO_3 framework caused the interlayer spacing to expand, and the band gap to shift to higher energy. The Sr~(2+) adsorption capacity of Ta-doped hex-WO_3 was significantly higher than that of hex-WO_3. Sr~(2+) adsorption reached equilibrium within 2 h in acidic solution. Maximum Sr~(2+) removal occurred at pH 4. Sr~(2+) uptake by hex-WO_3 was described better by the Freundlich model than by the Langmuir model. Sr~(2+) adsorption on hex-WO_3 was spontaneous under the studied conditions,