Photocatalytic Degradation of Reactive Black 5 Dye

Abstract

The textile industries use a number of dyes,chemicals and other materials to impart desired quality to the fabrics. These industries generate a substantial quantity of effluents, the quality of which in most of the cases is unsuitable for further use and can cause environmental problems, if disposed off without proper treatment. At present, due to the increasing resource constraints and the environmental requirements, these textile industries need to adopt a sustainable approach, and wastes generated therefore to be viewed as unutilized resources. Ways and means must be found to recover water and chemicals from these “waste” resources. The conventional treatment processes have various disadvantages and limitations, therefore, cannot be successfully implemented in the textile industry. Advanced oxidation processes seem to be promising as these methods can efficiently degrade the highly toxic and recalcitrant compounds and do not generate any secondary pollutants for disposal. Heterogeneous photocatalysis is the promising method among AOP’s to remove colorants and also to completely degrade into simple substances like CO₂, H₂O and mineral acids. Various catalysts are used of which one of the most is studied TiO₂ due to its unique features such as absolute and relative band positions. The main disadvantage of using TiO₂ is the recombination of electrons and holes which can decrease the efficiency of the process which can be overcome by doping TiO₂ with metals and non metals. This thesis seeks to give a method to study the kinetics of adsorption and of photocatalytic degradation of bare TiO2 as well as doped TiO2 which improves TiO₂ properties by doping with silver metal using liquid impregnation method. The dye used was Reactive black 5. The 1st chapter is an introduction, giving an overview of the situation and of the photocatalytic process as well as the literature review The 2nd chapter describes the materials and methods used during this research work. The 3rd chapter describes the kinetics of adsorption and of photocatalysis of undoped TiO2. The 4th chapter describes the kinetics of adsorption and of photocatalysis of silver doped TiO2.