How do dissolved gases affect the sonochemical process of hydrogen production? An overview of thermodynamic and mechanistic effects - On the "hot spot theory".

Kerboua, Kaouther; Merouani, Slimane; Hamdaoui, Oualid; Alghyamah, Abdulaziz; Islam, Md H; Hansen, Henrik E; Pollet, Bruno G

Kerboua, Kaouther; Merouani, Slimane; Hamdaoui, Oualid; Alghyamah, Abdulaziz; Islam, Md H; Hansen, Henrik E; Pollet, Bruno G.

Afiliación

Kerboua K; Higher School of Industrial Technologies, Department of Second Cycle, P.O. Box 218, 23000 Annaba, Algeria. Electronic address: k.kerboua@esti-annaba.dz.
Merouani S; Laboratory of Environmental Process Engineering, Faculty of Process Engineering, University Salah Boubnider - Constantine 3, 25000 Constantine, Algeria.
Hamdaoui O; Chemical Engineering Department, College of Engineering, King Saud University, P.O. Box 800, 11421 Riyadh, Saudi Arabia.
Alghyamah A; Chemical Engineering Department, College of Engineering, King Saud University, P.O. Box 800, 11421 Riyadh, Saudi Arabia.
Islam MH; Hydrogen Energy and Sonochemistry Research Group, Department of Energy and Process Engineering, Faculty of Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
Hansen HE; Hydrogen Energy and Sonochemistry Research Group, Department of Energy and Process Engineering, Faculty of Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway; Electrochemistry Research Group, Department of Materials Science and Engineering, Faculty of Natur
Pollet BG; Hydrogen Energy and Sonochemistry Research Group, Department of Energy and Process Engineering, Faculty of Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.

Ultrason Sonochem ; 72: 105422, 2021 Apr.

Article en En | MEDLINE | ID: mdl-33383540

RESUMEN

Although most of researchers agree on the elementary reactions behind the sonolytic formation of molecular hydrogen (H2) from water, namely the radical attack of H2O and H2O2 and the free radicals recombination, several recent papers ignore the intervention of the dissolved gas molecules in the kinetic pathways of free radicals, and hence may wrongly assess the effect of dissolved gases on the sonochemical production of hydrogen. One may fairly ask to which extent is it acceptable to ignore the role of the dissolved gas and its eventual decomposition inside the acoustic cavitation bubble? The present opinion paper discusses numerically the ways in which the nature of dissolved gas, i.e., N2, O2, Ar and air, may influence the kinetics of sonochemical hydrogen formation. The model evaluates the extent of direct physical effects, i.e., dynamics of bubble oscillation and collapse events if any, against indirect chemical effects, i.e., the chemical reactions of free radicals formation and consequently hydrogen emergence, it demonstrates the improvement in the sonochemical hydrogen production under argon and sheds light on several misinterpretations reported in earlier works, due to wrong assumptions mainly related to initial conditions. The paper also highlights the role of dissolved gases in the nature of created cavitation and hence the eventual bubble population phenomena that may prevent the achievement of the sonochemical activity. This is particularly demonstrated experimentally using a 20 kHz Sinaptec transducer and a Photron SA 5 high speed camera, in the case of CO2-saturated water where degassing bubbles are formed instead of transient cavitation.

Palabras clave

Dissolved gases; Hydrogen production; Mechanistic aspects; Sonochemistry; Thermodynamics

Texto completo

Añadir a Mi BVS

Imprimir

XML

PubMed Links

Buscar en Google

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Ultrason Sonochem Asunto de la revista: DIAGNOSTICO POR IMAGEM Año: 2021 Tipo del documento: Article Pais de publicación: Países Bajos

Texto completo

Añadir a Mi BVS

Imprimir

XML

PubMed Links

Buscar en Google