University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Flow effects on phenol degradation and sonoluminescence at different ultrasonic frequencies

Wood, Richard James, Vévert, Cédric, Lee, Judy and Bussemaker, Madeleine J. (2019) Flow effects on phenol degradation and sonoluminescence at different ultrasonic frequencies Ultrasonics Sonochemistry, 104892.

[img] Text
Phenol_Wood et al_Manuscript_Final.docx - Accepted version Manuscript
Restricted to Repository staff only until 26 November 2020.

Download (92kB)
[img] Text (Appendices)
Phenol_Wood et al_Appendices.docx - Supplemental Material
Restricted to Repository staff only until 26 November 2020.

Download (2MB)
[img] Text (Figures)
Phenol_Wood et al_Figures.docx - Supplemental Material
Restricted to Repository staff only until 26 November 2020.

Download (1MB)

Abstract

Current literature shows a direct correlation between the sonochemical (SC) process of iodide oxidation and the degradation of phenol solution. This implies phenol degradation occurs primarily via oxidisation at the bubble surface. There is no work at present which considers the effect of fluid flow on the degradation process. In this work, parametric analysis of the degradation of 0.1 mM phenol solution and iodide dosimetry under flow conditions was undertaken to determine the effect of flow. Frequencies of 44, 300 and 1000 kHz and flow rates of 0, 24, 228 and 626 mL / min were applied with variation of power input, air concentration, and surface stabilisation. Phenol degradation was analysed using the 4-aminoantipyrine (4-AAP) method and sonoluminescence (SL) images were evaluated for 0.1, 20 and 60 mM phenol solutions. Flow, at all frequencies under certain conditions, could augment phenol degradation. At 300 kHz there was excellent correlation between phenol degradation and dosimetry indicating a SC process, here flow acted to increase in bubble transience, fragmentation and radical transfer to solution. At 300 kHz, although oxidation is the primary phenol degradation mechanism, it is limited, attributed to degradation intermediates which reduce •OH radical availability and bubble collapse intensity. For 44 and 1000 kHz there was poor correlation between the two SC processes. At 44 kHz (0.01 mM), there was little to suggest high levels of intermediate production, therefore it was theorised that under more transient bubble conditions additional pyrolytic degradation occurs inside the bubbles via diffusion / nanodroplet injection mechanisms. At 1000 kHz, phenol degradation was maximised above all other systems attributed to increased numbers of active bubbles combined with the nature of the ultrasonic field. SL quenching by phenol was reduced in flow systems for the 20 and 60 mM phenol solutions. Here, where the standing wave field was reinforced, and bubble localisation increased, flow and the intrinsic properties of phenol acted to reduce coalescence / clustering. Further, at these higher concentrations, the accumulation of volatile phenol degradation products inside the bubbles are likely reduced in flow conditions leading to an increase SL.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Chemical and Process Engineering
Authors :
NameEmailORCID
Wood, Richard Jamesrichard.wood@surrey.ac.uk
Vévert, Cédric
Lee, Judyj.y.lee@surrey.ac.uk
Bussemaker, Madeleine J.m.bussemaker@surrey.ac.uk
Date : 25 November 2019
DOI : 10.1016/j.ultsonch.2019.104892
Copyright Disclaimer : © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Depositing User : Clive Harris
Date Deposited : 05 Dec 2019 13:16
Last Modified : 05 Dec 2019 13:16
URI: http://epubs.surrey.ac.uk/id/eprint/853234

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800