A Spectroscopic Study of Uranium and Molybdenum Complexation within the Pore Channels of Hybrid Mesoporous Silica

作者：Charlot Alexandre; Dumas Thomas; Solari Pier L; Cuer Frederic; Grandjean Agnes^*

来源：European Journal of Inorganic Chemistry, 2017, 2017(3): 563-573.

DOI：10.1002/ejic.201601085

• Uranium
• Molybdenum
• Speciation
• Mesoporous materials
• Silica
• EXAFS spectroscopy

To enable the reduction of the environmental impact of nuclear energy generation, in this paper, we link the molecular and macroscopic behaviour of a functionalized material (TR@SBA15) used to extract uranium from sulfuric media. Two organic 3-[N,N-di(2-ethylhexyl) carbamoyl]-3-[ethoxy(hydroxy)phosphoryl] propanoic acid (TR) molecules grafted onto the solid are involved in the extraction process and form a 2:1 TR-U complex. FTIR and extended X-ray absorption fine structure (EXAFS) spectroscopic analyses show that the TR-U bond is realized through a phosphonate group in a monodentate fashion below pH 3, in agreement with the macroscopic observations. The first coordination sphere of the uranyl ion is completed by two monodentate sulfate ions and one water molecule. Above pH 3, the TR contribution decreases, and other inner-sphere complexes appear, which is consistent with the increased extraction observed on the macroscopic scale. Molybdenum, a competitor element, reduces the uranium extraction capacity but not its speciation, whereas polyoxomolybdates form inside the pores from the molybdenum in solution.

• 出版日期2017-1
• 单位中国地震局