Advanced Oxidation Processes for Removal of Dyes from Aqueous Media - Green Chemistry for Dyes Removal from Wastewater - page 110

The AOPs can be classified in terms of whether UV source is used in the
process as non-photochemical and photochemical processes. If an over-
view of several AOPs is performed and their effectiveness in the degra-
dation of all kinds of dyes is compared, there are mainly four treatment
technologies that hold the greatest promise: ozonation, Fenton's reagent
oxidation, wet air oxidation and photocatalytic oxidation.
The principal mechanism of the AOPs function is the generation of
highly reactive free radicals. A combination of two or more AOPs gen-
erally enhances free radical generation, which eventually leads to higher
oxidation rates.
Much research has been performed within the field of advanced oxida-
tion of dyes and there is no doubt that these methods work and are effi-
cient for elimination of dyes in wastewaters. However each method has
its own advantages and disadvantages. The different methods may result
in different intermediates since toxicity patterns for the applied treat-
ments are substantially different. They may also differ in the optimum
operating parameters with respect to the wastewater quality and quan-
tity. Consequently, it is the researchers' responsibility to choose the most
appropriate treatment method for their cases.
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