Use of Pillared Clay-Based Catalysts for Wastewater Treatment Through Fenton-Like Processes

Abstract

Clays, both natural and physical-chemically modified, are attractive materials for the preparation of supported catalysts. In this chapter, a review is made regarding the use of pillared interlayered clays (PILCs) in heterogeneous Fentonlike advanced oxidation processes. Their applications in pollutants degradation is summarized, with particular emphasis on the effect of the main operating conditions (e.g., initial H 2 O 2 or parent compound concentration, catalyst load, pH, or temperature) on oxidation efficiency. Special attention is also given to the type of catalyst or precursor used, to the importance and advantages of the heterogeneous versus homogeneous process, and to significant aspects like catalyst stability. Among the technological issues that are of concern, the importance of using continuous flow reactors (e.g., fixed-bed) is discussed. Finally, some mechanistic studies are reviewed as well as modeling works, based on phenomenological or semi-empiric models (e.g., using statistic tools like design of experiments).

Research Trends on Pillared Interlayered Clays (PILCs) Used as Catalysts in Environmental and Chemical Processes: Bibliometric Analysis

“…Since the 2000s, the application of PILCs in environmental processes has become more frequent [11,[49][50][51], especially in the treatment of pollutants in gas or liquid phases through advanced oxidation processes, as displayed in Figure 1. In particular, photo-oxidation and CWPO processes have been extensively studied in the treatment of pollutants in water [3,10,11,50].…”

“…Biological, physical, and chemical techniques have been used for wastewater treatment. Nevertheless, some of the conventional methods (e.g., filtration, adsorption, and coagulation-flocculation) for wastewater treatment do not degrade pollutants but simply transfer contaminants from one phase to another [ 3 ]. Furthermore, several of these pollutants are recalcitrant to biological degradation and toxic to microorganisms.…”

“…In recent years, advanced oxidation processes (AOPs) have been studied for the removal of a wide number of organic contaminants to increase wastewater biodegradability as a pretreatment prior to a subsequent biological treatment [ 4 , 5 ]. Versatility of AOPs is further boosted by the fact that they may generate •OH radicals in a variety of ways [ 3 , 6 , 7 ]. Currently, the three AOPs that have been most widely studied are heterogeneous photocatalysis (TiO 2 ), photo-Fenton process, and H 2 O 2 /UV [ 4 ].…”

Application of Nanocatalysts in Advanced Oxidation Processes for Wastewater Purification: Challenges and Future Prospects

“…These above-stated limitations affect the catalysts' life and cause the deactivation of the catalysts. Such catalysts are not suitable for long duration processes and cannot be reused [96]. Table 9 summarizes the application of clays as nanocatalysts in AOPs for wastewater treatment.…”

Evaluación y caracterización de nanotubos de TiO2 sintetizados por vía hidrotérmica con aplicación en ingeniería de materiales

“…) de peróxido, se observa un descenso del 10% en la fotocatálisis pues cuando hay exceso de reactivo, se lleva a cabo de nuevo la completa descomposición en O 2 y H 2 O perdiendo su poder fotocatalítico[29].HO 2 • + HD • → H 2 O + O 2 (8) H 2 O 2 + HO • → HO 2 • + H 2 O…”