Heterogeneous Photocatalysis Remediation of Wastewater Polluted by Indigoid Dyes

Abstract

Organic dyes constitute one of the largest groups of wastewater's pollutants. In general, they are released into the environment by textile industries. "pproximately , dyes are widely used in the textile industry, and a large wastewater of dyestuff is generated annually. "mong 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 TiO has some advantages such as ease of handling, low cost, low toxicity, high photochemical reactivity, and nonspecific 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 TiO . "dsorption over activated carbon "C 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.

Autocombustion‐Promoted Synthesis of Lanthanum Iron Oxide: Application as Heterogeneous Catalyst for Synthesis of Piperidines, Substituted Amines and Light‐Assisted Degradations

“…Besides this, the temperature also affects the percentage of the food colorant degraded as it relates with the e À /h + recombination rate. [121,122] This was observed to be true for our case also as the degradation efficiency was comparatively more under refluxing compared to under U.V. light and sonication.…”

Green Synthesis and Characterization of LED-Irradiation-Responsive Nano ZnO Catalyst and Photocatalytic Mineralization of Malachite Green Dye

“…Firstly, we tested the photodegradation of MG dye under different molar ratios. Upon irradiation of the Fe 3+ /H 2 O 2 /ZnO/MG method in the presence of LEDs irradiations, we found improved degradation of the MG dye, as compared to the dye solution without ZnO NPs (Figure 5) [41][42][43].…”

Photocatalytic degradation of swine wastewater on aqueous TiO2 suspensions: optimization and modeling via Box-Behnken design

“…During the photochemical degradation of SWW, pollutant removal may proceed primarily due to organics oxidation at the TiO 2 surface utilizing hydroxyl radicals formed from the reaction between photogenerated holes and adsorbed water. The mechanism of generation of these strong oxidants is described in the following equations [8,30,31]:…”

“…These results are probably due to the higher amount of hydroxyl radicals formed at higher photocatalyst dosages. In fact, as the number of active sites available increases due to more photo-generated electron-holes, the higher the oxidants produced, which results in increasing removal efficiency [31,33]. On the other hand, issues with light penetration at higher catalyst dosages have been reported.…”