Electrochemical investigation of transient bubble phenomena
Electrochemical investigation of transient bubble phenomena
Coupling electrochemistry to ultrasound had led to numerous applications. In this work, a microelectrode (typically 5μm diameter Pt) was employed as a probe to investigate the effect of physical parameters, such as frequency and pressure amplitude, on mass transfer to a microelectrode. The sound field created by a sandwich transducer (frequency range 20 to 12 kHz) cylindrical cell was characterised using AC impedance, sonochemiluminescence and sound measurements. Light patterns and local pressure measurements were found to be consistent with a standing wave model with modal functionality creating activity zones in the sonochemical cell. Furthermore, evidence are presented for the existence of streamers, stable and transient cavitation. Mass transfer to a microelectrode was investigated and the results reported show a good agreement between sonochemiluminescence and electrochemical studies. Activity zones were also detected proving that the microelectrode resolution was sufficient to distinguish between transient and stable cavitation. Average mass transfer coefficients to up to 0.6 cm s-2 are reported with [Ru(NH3)6]3+ as the redox species.
Finally, a new gas blowing system is introduced. This allows higher mass transfer to be obtained as the result of solution perturbation caused by rising bubbles. Comparisons are made between transient bubbles formed by ultrasound and bubbles arising from the buoyancy forces. This system was used to measure the kinetic of simple redox couples.
University of Southampton
Delaplace, Christine Louise
1999
Delaplace, Christine Louise
Delaplace, Christine Louise
(1999)
Electrochemical investigation of transient bubble phenomena.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Coupling electrochemistry to ultrasound had led to numerous applications. In this work, a microelectrode (typically 5μm diameter Pt) was employed as a probe to investigate the effect of physical parameters, such as frequency and pressure amplitude, on mass transfer to a microelectrode. The sound field created by a sandwich transducer (frequency range 20 to 12 kHz) cylindrical cell was characterised using AC impedance, sonochemiluminescence and sound measurements. Light patterns and local pressure measurements were found to be consistent with a standing wave model with modal functionality creating activity zones in the sonochemical cell. Furthermore, evidence are presented for the existence of streamers, stable and transient cavitation. Mass transfer to a microelectrode was investigated and the results reported show a good agreement between sonochemiluminescence and electrochemical studies. Activity zones were also detected proving that the microelectrode resolution was sufficient to distinguish between transient and stable cavitation. Average mass transfer coefficients to up to 0.6 cm s-2 are reported with [Ru(NH3)6]3+ as the redox species.
Finally, a new gas blowing system is introduced. This allows higher mass transfer to be obtained as the result of solution perturbation caused by rising bubbles. Comparisons are made between transient bubbles formed by ultrasound and bubbles arising from the buoyancy forces. This system was used to measure the kinetic of simple redox couples.
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Published date: 1999
Identifiers
Local EPrints ID: 464075
URI: http://eprints.soton.ac.uk/id/eprint/464075
PURE UUID: 2479325e-39c5-4300-bd6b-7dc5b98b5856
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Date deposited: 04 Jul 2022 21:02
Last modified: 04 Jul 2022 21:02
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Author:
Christine Louise Delaplace
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