AN INVESTIGATION OF CATALYTIC OZONATION OF ORGANIC COMPOUNDS
Report No FR/INV0002
R Burch and C Cooper
The aim of the research was to investigate the possible use of
inorganic catalysts to enhance the effectiveness of ozone in the
destruction of recalcitrant compounds. The use of ozone for water
treatment has increased significantly in recent years and is now
available for relatively large-scale operation. However, advantages
would be gained if either the rate of ozonation or the efficiency
with which ozone is utilised could be improved. At the start of the
project there were few references to the use of catalytic ozonation
and it was not clear whether there were any real benefits. In our
research, therefore, the emphasis has been on assaying a number of
potential catalysts. Initially we used model organic compounds to
try to assess the potential of the process, especially when applied
to real water samples. Among the objectives were:
- to investigate the adsorption of selected organic compounds from
aqueous solution onto specific catalysts and supports;
- to determine whether catalytic ozonation can be applied to real
- to provide an assessment of the potential of catalytic ozonation
as an advanced oxidation process.
The major conclusions of the work are listed below:
- Using oxalic acid as a model test compound, it was confirmed that
catalysts can increase the rate of oxidation by ozone. There does
not appear to be any significant difference between catalysts
comprising different oxides supported on aluminium oxide, possibly
indicating an important role for the adsorption of oxalic acid in
the oxidation process.
- Catalytic ozonation is effective for the removal of atrazine from
real water samples.
- The beneficial effect of a catalyst seems to be enhanced at lower
temperatures (typically 8°C compared to 22°C), with the rate of
removal of atrazine being up to five times faster in the presence
of a catalyst.
- The catalytic destruction of atrazine leads to the formation of
primary, secondary and tertiary products. The reaction pathway
- seems to be similar to that observed for ozonation in the absence
of a catalyst.
- Mesoporous silicas seem especially interesting as potential
adsorbents and catalysts.
- Recent literature suggests that catalytic ozonation is
significantly more economical than conventional ozonation in terms
of ozone utilisation.
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