Aayushi, Shivam Pandey
Wastewater from textile and allied sectors offers nearly 15%–20% of global industrial water pollution, with dye concentrations generally ranging from 10 to 200 mg/L, making it a considerable environmental concern. Synthetic dyes are hazardous, prolonged, and toxic in nature. Conventional treatment procedures, such as physical, chemical, and biological processes, sometimes have issues, including being non-biodegradable, leading to secondary pollution such as sludge generation, production of toxic by-products, partial mineralization, and being cost-intensive. Photocatalysis has recently developed as an efficient advanced oxidation technique for dye degradation, employing semiconductor photocatalysts such as TiO 2 , ZnO, and graphitic carbon nitride that are commonly used under light irradiation to produce reactive oxygen species that mineralize dyes into non-toxic byproducts. In comparison with conventional AOPs such as Fenton and ozonation, photocatalysis provides significant benefits, including lower chemical consumption, reduced sludge generation, catalyst reusability, and potential for solar-driven operation. The present review focuses on catalytic strategies, specifically on photocatalytic degradation of dyes, as a sustainable way for improving the environmental efficiency of textile processes. Major operational factors such as pH, catalyst loading, light intensity, and initial dye concentration are discussed in detail. The review highlights that advanced composite and immobilized photocatalysts demonstrate significantly upgraded degradation efficiency, enhanced charge separation, and better reusability as compared to single-component systems. Moreover, a comparative analysis of conventional and advanced treatment methods is presented, demonstrating that photocatalysis provides higher mineralization efficiency with reduced secondary pollution, making it a viable strategy for wastewater treatment.