Dear Arasan,

There are many articles and papers published that employ advanced oxidation processes (AOP) for the degradation of many types of dyes. In these articles pathways are investigated further degradation by photocatalysis, mainly variants of the photo-Fenton processes. The efficiency of these processes is subject to formation of hydroxyl radical (ºOH). Transient species with a high oxidizing power which can promote the complete mineralization of organic molecules to CO2 and H2O. In this sense I sugest these follow articles:

1 - TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations: A review;

2 - TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations: A review;

3 - Aromatic amines from azo dye reduction: status review with emphasis on direct UV spectrophotometric detection in textile industry wastewaters

Have a nice job,

Rodrigo

thanks friend 

In photodegradation the radicals are formed by the decomposition of the dye which depends up on the type of the dye & the reaction is proceeds the formation of the stable products is observed