Organic dyes constitute one of the largest groups of wastewater’s pollutants. In general, they are released into the environment by textile industries. Approximately 100,000 dyes are widely used in the textile industry, and a large wastewater of dyestuff is generated annually. Among these, indigoid class is commercial dyes used mostly for cotton cloth dyeing. Indigo carmine (IC) is also one of the oldest dyes and still one of the most used in textile industry and is considered as a very toxic indigoid dye. Most toxic dyes are recalcitrant to biodegradation, causing a decrease in the efficiency of biological wastewater treatment plants. Titanium dioxide is a well-known photocatalyst mostly used in suspensions in photoreactions for wastewater treatment. The use of TiO2 has some advantages such as ease of handling, low cost, low toxicity, high photochemical reactivity, and non-specific oxidative attack ability. In this way, it can promote the degradation of different target organic compounds with little change of operational parameters. The aim of this chapter is to present the different approaches already used in our team for the remediation of waters containing IC mainly through heterogeneous photocatalysis with TiO2. Adsorption over activated carbon (AC) and photocatalytic degradation of IC mediated by titanium dioxide will be revised as well as some studies on the phototoxicity of the photoproducts with aquatic and terrestrial organisms. This chapter makes a comprehensive approach to the different results on the remediation of model effluents containing IC undertaken by this team of researchers.
Part of the book: Textile Wastewater Treatment