Metal Nanoparticles as Heterogeneous Fenton Catalysts

Abstract

The Fenton reaction (the generation of hydroxyl radicals from hydrogen peroxide) is the most useful method for degradation of organic pollutants in aqueous solution at moderate concentrations. In this Review we summarize the use of metal nanoparticles, either unsupported or deposited on large-surface-area solids, as Fenton catalysts. The Review complements two other reviews in the field of heterogeneous Fenton catalysis using aluminosilicates and carbonaceous materials. Herein, particular emphasis is given to the reaction conditions in which these catalysts are used, highlighting the operating mechanism and the relative efficiency of the materials. Aspects such as leaching of the metal to the solution, reusability, and the concentration of hydrogen peroxide used are analyzed in detail. Besides a critical description of the present status of the field, future trends and the need to establishing valid comparisons to assess the relative efficiencies of the materials are commented on.

MIL-101 promotes the efficient aerobic oxidative desulfurization of dibenzothiophenes

“…This HOO · radical will be formed from O 2 ·-by protonation by moisture present in the medium and constitutes and experimental evidence of the involvement of the generated reactive oxygen species by acting MIL-101(Cr) solid as initiator. 23 Selective radical quenching experiments using p-benzoquinone 59 and 1035 cm -1 have been detected when the sample was exposed to O 2 flow at 120 ○ C. These bands have been attributed to peroxo and superoxo species, respectively.…”

Preparation of magnetite-based catalysts and their application in heterogeneous Fenton oxidation – A review

“…is associated to their inherent properties, which can differ from those of the macroscopic or bulk forms of the same material [83]. Furthermore, their activity and selectivity are strongly dependent on their size, shape and surface structure, as well as on their bulk composition, which can be appropriately tuned during their synthesis.…”

“…The synthesis of MNPs can be carried out by different methods such as co-precipitation [41,84], microemulsion [85], hydrothermal [86,87] or sonochemical synthesis [88], among other [83].…”

“…Co-precipitation is, by far, the most commonly applied method [83,89]. It is based on mixing ferric and ferrous ions, commonly in a 1:2 molar ratio, in highly basic solutions at room or higher temperature.…”

Interfacial mechanisms of heterogeneous Fenton reactions catalyzed by iron-based materials: A review

“…Different from other published reviews, which have focused on the preparation and performance of the catalysts (Dhakshinamoorthy et al, 2012;Garrido-Ramirez et al, 2010;Navalon et al, 2010a;Nidheesh, 2015;Perathoner and Centi, 2005), this article reviews the fundamental interfacial mechanisms of the heterogeneous Fenton reactions catalyzed by iron-based materials, which may also provide insights for the enhancement of heterogeneous Fenton reactions with additional energy, such as ultraviolet and visible light (UV-Vis), electricity, and ultrasound.…”