Advanced Oxidation Processes (AOP)—Effective Innovative …
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Fig. 2 Advanced oxidation process [30]
2.1 Types of Advanced Oxidation Process
There are many types of advanced oxidation processes, and classification is made
according to the mode of release of the oxidizing agents [30] (Fig. 3).
3 Chemical AOPs
3.1 Ozonation
Ozone consists of three oxygen atoms and is a very unstable gas, due to its unstable
nature, the gas readily converts to oxygen, and during this transformation, a free
oxygen atom or free radical is being released. The free radical form of oxygen
generated will be highly reactive, also has a shorter life time, and it can survive only
for few milliseconds.
Ozone is a colourless gas, and the smell of the ozone gas is similar to the odour
of the air after thunderstorm. Ozone is a great disinfectant and efficient in treating
bacteria and viruses [31], and it is already used for water purification nowadays,
replacing chlorine. Apart from this, ozone is used to eliminate taste and odour problems, by reducing the concentration of sulphur, iron, manganese in water. The iron,