Poster De Conférence Année : 2012

Multibubble sonoluminescence and sonochemistry of f-elements

Résumé

This paper summarizes recent studies performed at Marcoule Institute for Separation Chemistry (ICSM) in the topic of multibubble sonoluminescence (MBSL) and sonochemistry of UO2 2+ and lanthanide(III) ions in aqueous solutions and at the solidliquid interface. Power ultrasound has showed to be effective for excitation of volatile and non-volatile species in solutions in many cases. The observed effects are generally attributed to acoustic cavitation which is the nucleation, growth, and rapid implosive collapse of vapor filled micro-bubbles during the ultrasonic irradiation of a liquid medium. Bubble collapses in liquids produce chemically active species (excited species and radicals such as OH°) as well as sonoluminescence (SL, emission of light from the core of collapsing bubbles). MBSL spectra of pure water sparged with noble gases consist of OH° radical emissions from A2+ and C2+ electronically excited states and a broad continuum spanning from the UV to the near IR spectral range. 1 This continuum is generally attributed to bremsstrahlung, to H + OH° recombination, and possibly to water molecules deexcitation or OH(B2Σ+-A2Σ+) emission. SL from alkali-metal salt solutions exhibits emission from the excited alkali-metal atoms M and M·Ar exiplex species. 2 Such kind of SL was explained by nanodroplet injections into the hot cores of collapsing bubbles. 3 Recently, the SL of lanthanide ions was reported in concentrated (0.5-1.0 M) aqueous lanthanide salt solutions under the effect of 20 kHz ultrasound. 4 It was suggested that the SL of lanthanides would be governed by two major processes: (i) sonophotoluminescence, when the excitation of Ln(III) ions occurs through the light emitted from cavitation bubbles and (ii) collisional excitation of Ln(III) ions by ʺhotʺ particles at the bubble/solution interface. However, the mechanism of metal ions excitation under sonication is still under debate. In this paper, we report on the parameters that influence MBSL of f-elements and on its quenching by sonolytical products and collisions with hot species at the bubble interface. Under proper conditions, the uranyl ion exhibits ultrabright sonoluminescence even in relatively diluted solutions. On the other hand, we show that SL can be used as a source of excitation for fluorescent f-elements contained in an extended solid phase.5

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hal-04765979 , version 1 (04-11-2024)

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  • HAL Id : hal-04765979 , version 1

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Matthieu Virot, Rachel Pflieger, Tony Chave, Sergey I. Nikitenko. Multibubble sonoluminescence and sonochemistry of f-elements. Journées Nationales de Radiochimie, Oct 2012, Nantes, France. ⟨hal-04765979⟩
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