Fundamentals and mechanistic pathways of dye degradation using photocatalysts

Dyes play a major role in our life as they are found in various products ranging from clothes, leather accessories, furniture, etc. However, adverse side effects of waste dye discharged mostly to the water supply make it a pollutant. Various approaches have been developed to remove and degrade these carcinogenic dyes and of which one of the advanced oxidation process include photocatalysis. The aim of this chapter is to address the fundamentals of photocatalysis and mechanistic pathways of dye degradation using photocatalysts. Preparation methods for photocatalyst include sol-gel, hydrothermal, CVD, etc. There are many factors that can affect the efficiency of this process such as catalyst loading, solution pH, light intensity, concentration of dye, dopant content, etc. The mechanism of photodegradation depends on the radiation used and the pathways of azo dyes degradation show the formation intermediates created during their degradation.