Wastewater treatment by heterogeneous fenton-like processes in continuous reactors

Abstract

The treatment of several industrial effluents, such as textile, pharmaceutical, and phenol-containing wastewaters, often face limitations toward conventional treatment processes. Solutions for such problematic include the use of several advanced oxidation processes (AOPs) and particularly the Fenton one. However, most of the research has been focused in the homogeneous process, while recent trends point for the use of heterogeneous systems, with the catalyst immobilized in a solid support. In addition, process optimization and catalyst screening are commonly carried out in batch reactors, which often are not the best solution for continuous industrial units. In this chapter, a review is made regarding the application of heterogeneous Fenton-like advanced oxidation processes in continuous systems (fixed-bed, fluidized-bed, and continuous stirred-tank reactors). The application of this catalytic process for pollutant/wastewater treatment is summarized, giving emphasis to the effect of the key operational parameters (e.g., pH, feed dose of H2O2, catalyst load, and feed flow rate) affecting the oxidative performance of such systems. Moreover, the main physicochemical properties of heterogeneous catalysts (e.g., source of support and particle size) and preparation methods (e.g., type of precursor and metal ion) affecting the catalytic efficiency of Fenton’s oxidation, and the stability of the catalyst itself, are also discussed. Finally, some operational issues of concern regarding solid catalysts operating in continuous-flow reactors are addressed.