Photocatalytic degradation of dyes using semiconductor photocatalysts to clean industrial water pollution

Textile industry represents a pollution problem worldwide due to the accidental discharge or dumping of polluted wastewater into the waterways, which is having a major influence on the quality of water resources. Around 17–20% of industrial water pollution arises from textile dyeing and treatment according to the World Bank report. This represents a large environmental challenge for textile manufacturers. With growing environmental awareness, there is a need for environmentally-friendly technology to remove dyes from the industrial and local wastewater. The photo decolorization of dyes is considered as a favorable technology for industrial wastewater treatment techniques owing to its environmentally friendly method, low cost, and lack of secondary pollution. The efficiency of photocatalysis system depends on the operational parameters that govern the adsorption and photodegradation of dye molecules. This comprehensive review examines the operational factors influencing the photo decolorization of dye molecules. Our study aims to review and summarize the previously published works and R&D progress in the field of photocatalysis of various water pollutants such as the toxic organic compounds (cationic and anionic dyes) using various semiconductor nanoparticles under visible, solar and UV irradiation. This paper examines the effects of operating parameters on the photocatalytic degradation of textile dyes using various photocatalysts. Our findings showed that various parameters, like initial pH of the solution to be degraded, photocatalyst concentration, reaction temperature, dye concentration and dopants content exert their individual influence on the photocatalytic degradation of any dye. By investigating previous research to elucidate the most significant active species for optimal photo decolorization reactions, this review provides guidelines that can be applied to the development of effective photodegradation systems. The results of our study will help determine the most effective and economical options for removal of dyes in industrial wastewater.