Photocatalytic degradation of organic dyes using heterogeneous catalysts

Abstract Organic dyes are nonbiodegradable chemicals that are imperative to our everyday life as they are found in a number of products such as leather accessories, textiles, furniture, etc. The drawback of their extensive usage is the fact that during dyeing process 12% of these dyes are wasted and nearly up to 20% of it ends up in the water supply and poses a serious risk to the environment and human life. Owing to the potential toxicity, degradation of dyes from wastewater needs urgent attention. To overcome the problem, several methods were introduced in the past among which the heterogeneous photocatalysis emerges as a promising cure for dye pollution. In this chapter, our endeavor is to scrutinize and summarize the current research on heterogeneous photocatalytic systems for dyes degradation. The chapter starts with a brief outline on dye pollution, their classification, and type of photocatalytic system used in degradation process, in particular aiming at TiO2, ZnO, and photo Fenton process. The recent advancements to enhance photocatalytic efficiency, effects of strategic operational parameters on the photocatalytic performance are detailed. Brief synopsis on the analytic methods used for identification of reaction intermediates that are produced during dye degradation is discussed.