Sound waves and bubbles could
provide a cheap and safe way to treat industrial
waste, research in the school of chemical
engineering has found.
Dr Maria Papadaki and PhD student
Richard Emery are investigating whether ultrasound
high frequency sound waves more commonly
known for their use in medical and industrial
imaging could be used to break down
the chemicals in industrial waste which prevent
it being naturally biodegradable.
When ultrasound is used
on a liquid, bubbles are formed, which grow
and then collapse, said Dr Papadaki.
Extreme temperatures of several thousand
degrees and pressures of several hundred atmospheres
are created within the bubbles during their
collapse, turning them into tiny hot spot
microreactors in an otherwise cold liquid.
The reactions taking place within these bubbles
break down the chemical compounds.
Dr Papadaki is looking at the
waste from the pharmaceutical industry, much
of which is resistant to natural biodegradation,
but the results could translate to other industries
with wastewaters. The technique has proved
successful with some of the common waste compounds,
but further research is still required to
see if the process could be applied on an
The aim is to construct
a safe, cost-effective and environmentally
friendly way of treating otherwise highly
toxic wastes, said Dr Papadaki. We
are analysing how different frequencies, powers
and temperatures affect the process, and the
final products. The research is funded
by the EPSRC and GlaxoSmithKline.