It is most widely reported that the Reactive oxygen species is involved in the photodegradation process to mineralize the pollutants into H2O and CO2 completely. However, the mechanisms used are not still explained well.
Firstly water and carbon dioxide are not minerals. Also use of reactive oxygen species are mostly used for organic pollutants. The basis for the mechanism is photo Fenton chemistry to generate superoxide and hydroxyl radicals. These then can perform hydrogen abstractions, oxidations and scissions.