
Sonochemistry Ultrasonics Research Group
We work with the propagation of ultrasound waves through a liquid medium that can lead to the creation of acoustic cavitation bubbles. These cavitation bubbles can emit light (sonoluminescence) and undergo violent collapse to generate extreme temperatures (> 5000 k), pressures (> 1000 atm) and jet velocities (up to 120 m/s has been reported).
Overview
It is these remarkable conditions that allow ultrasound to create unusual physical and chemical properties ideal for degradation of pollutants, synthesis of polymers and nanomaterials. However, to capitalise on these effects, one needs to understand how the physical and chemical properties vary under different solution and sonication conditions such as frequency and power.
Ultrasonic processing has applications in heterogeneous and homogeneous environments, and is able to augment chemical processes via the well-known mechano acoustic and sonochemical effects from the cavitation bubbles. This can enhance radically driven processes, as well as mixing, emulsification and molecular accessibility.
The mechanism and level of enhancement is influenced by the reactor configuration (geometry, transducer type, frequency, flow, power) and the characteristics of the medium (gases present, solid loading, form of the solute, pH etc). Therefore it is of interest to investigate the effect of these parametric variations to further capitalise on the bubble dynamics to enhance the desired ultrasonic effects.
Available equipment
The equipment we have available is able to investigate the various parametric effects of ultrasound on a multitude of processes, aimed at understanding the fundamental interactions toward process improvement and optimisation.
Who we collaborate with
Examples

Scanning electron microscopic images of NaCl crystals obtained under different mixing and ultrasound irradiation.

Pitting and cracking on wheat straw caused by ultrasonic cavitation (Bussemaker et al., Bioresour. Technol. 2013)

Sonoluminescemce (left) and sonochemiluminescence (right) at 300 kHz, 20 W input power.
Facilities

Multi-frequency reactor and amplifier sets consisting of an amplifier, transducer, impedance matching and different reactor options for specialised work.

The cavitation within an ultrasonic cleaning bath can be demonstrated with a simple aluminium foil test and provides a good comparison of ultrasonic applications, repeatability and effects at low frequencies and powers.

Ultrasonic horn is a high power, low frequency means of introducing ultrasound into solution. The tip of the horn is interchangeable with a micro-tip and is used for emulsification applications, cell deactivation.

The pilot scale test rig was donated by Bio-Sep Ltd. The flow through cell allows for larger scale ultrasonic applications at elevated temperatures and pressures.

The ultrasonic field can be calibrated using different methods. We can perform iodide dosimetry with spectrophotometric analysis; imagery analysis, visualising sonoluminescence or sono chemiluminescence, hydrophone pressure measurements and calorimetric analysis.
Our people
Select the profiles below to view their publications.
Lead researchers

Dr Madeleine Bussemaker
Senior Lecturer in Chemical Engineering

Dr Judy Lee
Reader, Director of Learning and Teaching for Chemical and Process Engineering
Contributing academics

Dr Ralph Chadeesingh
Senior Teaching Fellow

Dr Devendra Saroj
Reader and Head of Centre for Environmental Health and Engineering (CEHE), Director of Research - Department of Civil and Environmental Engineering

Dr Richard Sear
Reader, Soft Matter Group leader

Dr Eirini Velliou
Visiting Senior Lecturer
Postgraduate research students

Dr Pello Alfonso Muniozguren
Application of advanced oxidation assisted processes for industrial wastewater treatments

Dr Katie Costello
Listeria growth in structured food models: Towards modelling microbial kinetics and potential antimicrobial resistance in structured cheese models as affected by emerging technologies

Dr Silvia Nalesso
Ultrasound simulated crystallisation of functional materials

Tim Sidnell
Ultrasonic degradation of per- and polyfluoroalkyl substances

Dr Richard James Wood
Parametric control and augmentation of sonochemical activity in aqueous solutions