title: Activating molecules, ions, and solid particles with acoustic cavitation.
abstract: The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration: sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO2 powder in pure water yields stable colloids of plutonium due to both effects.
authors.affiliation: Marcoule Institute for Separative Chemistry, UMR 5257 CEA-CNRS-UM2-ENSCM.
authors.forename: Rachel
authors.initials: R
authors.lastname: Pflieger
authors.affiliation: Marcoule Institute for Separative Chemistry, UMR 5257 CEA-CNRS-UM2-ENSCM.
authors.forename: Tony
authors.initials: T
authors.lastname: Chave
authors.affiliation: Marcoule Institute for Separative Chemistry, UMR 5257 CEA-CNRS-UM2-ENSCM.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Virot
authors.affiliation: Marcoule Institute for Separative Chemistry, UMR 5257 CEA-CNRS-UM2-ENSCM; serguei.nikitenko@cea.fr.
authors.forename: Sergey I
authors.initials: SI
authors.lastname: Nikitenko
mesh_terms: D000162:Acoustics; D001128:Argon / Q000737:chemistry; D002248:Carbon Monoxide / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D008163:Luminescent Measurements / Q000379:methods; D045423:Microbubbles; D017785:Photons; D010984:Platinum / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D014465:Ultrasonics / Q000379:methods*
chemical_list: D002412:Cations; D005740:Gases; D012996:Solutions; D010984:Platinum; D001128:Argon; D002248:Carbon Monoxide
references.citation: Small. 2005 Oct;1(10):964-7
references.pmid: 17193378
references.citation: J Phys Chem A. 2012 May 24;116(20):4860-7
references.pmid: 22559729
references.citation: J Colloid Interface Sci. 2013 Apr 1;395:81-4
references.pmid: 23347995
references.citation: Angew Chem Int Ed Engl. 2009;48(50):9529-32
references.pmid: 19921666
references.citation: Chemistry. 2012 Jan 9;18(2):410-4
references.pmid: 22162044
references.citation: Chemistry. 2010 Oct 18;16(39):11801-3
references.pmid: 20821771
references.citation: Chemistry. 2012 Mar 26;18(13):3879-85
references.pmid: 22362626
references.citation: Angew Chem Int Ed Engl. 2013 Feb 25;52(9):2478-81
references.pmid: 23355372
references.citation: Ultrason Sonochem. 2001 Jan;8(1):1-6
references.pmid: 11105315
references.citation: Ultrason Sonochem. 2010 Aug;17(6):1033-40
references.pmid: 20022548
references.citation: J Phys Chem B. 2013 Mar 14;117(10):2979-84
references.pmid: 23421489