Recent Trends in Nanomaterial-Based Advanced Oxidation Processes for Degradation of Dyes in Wastewater Treatment Plants

Abstract

Industrial sectors such as textile, printing, iron-steel, petroleum, agriculture, paper, pharmaceuticals and food, just to name a few, are the main sources of dye discharge into wastewater effluent plants. Most of these dyes are notorious, are nonbiodegradable and can change water appearance, even at low concentration levels (from 1 ppm). It is well reported that polluted water is a crucial factor in the reduction of biodiversity and socioeconomic development. Therefore, effective water purification technologies are urgently required for the removal of dyes. Studies have shown that the application of advanced oxidation processes (AOPs) for the degradation of toxic organic pollutants in wastewater is promising when compared to traditional methods. The AOP technologies make use of strong oxidizing reagents such as hydroxyl radicals, ozone, superoxide radical and so on. Currently, there is a growing interest in the use of nanomaterials to overcome some of the challenges reported for conventional AOPs. Therefore, this chapter evaluates various nanomaterials applied in AOPs for the degradation of dyes in wastewater by looking at oxidation rates and degradation efficiencies achieved. Furthermore, degradation mechanisms are described in depth for various dye compounds. Finally, recommendations for the future improvement of dye degradation by nanomaterial-based AOPs are elaborated.