## 1 Introduction  
Advanced Oxidation Processes (AOPs) are capable of degrading recalcitrant toxic pollutants, which are not possible to eliminate through other treatment methods. These advanced processes are based on the generation of a highly reactive species (hydroxyl radicals, OH ), which oxidize the organic pollutant [1]. The most common AOP is the Fenton reaction; this is based on the reaction of H\({}_{2}\)O\({}_{2}\) with iron ions. Although the aforementioned process is efficient, some of the main disadvantages of this treatment are the industrial production, storage, transportation of the H\({}_{2}\)O\({}_{2}\) and the formation of sludge. To avoid these problems, solid supports that include iron or metals compounds in their structure have begun to be used to provide the active oxygen species needed for the Fenton process, this AOP has been called Electrofenton-like. This methodology has advantages over the Fenton process; hydrogen peroxide is produced directly on the electrode surface and the presence of iron ions in solution avoids the formation of sludge and allows the recovery of the catalyst at the end of the treatment. Many studies are being directed towards the immobilization of iron species or insoluble iron oxides. Hydrogen peroxide can be continuously electrogenerated at the cathode electrode by the reduction oxygen via two electrons (Reaction (1)), follow by further 2 electron reduction to H\({}_{2}\)O, (Reaction (2)). Oxygen can also be reduced directly to water via four electrons (Reaction (3)), these processes can occur simultaneously, and therefore decrease the concentration of hydrogen peroxide needed. To avoid this, it is necessary to check that the potential does not exceed the value corresponding to Reaction (1). In addition, the presence of iron ions also favorably catalyzes Reaction (1) instead of the other reactions. \[\text{O}_{2}(\text{g})+2\text{H}^{+}+2\text{e}^{-}\rightarrow\text{H}_{2}\text{ O}_{2}\text{ E}^{0}=0.695\text{ vs. SHE} \tag{1}\]  
\[\text{H}_{2}\text{O}_{2}+2\text{H}^{+}+2\text{e}^{-}\rightarrow\text{2H}_{2} \text{O}\text{ E}^{0}=1.776\text{ vs. SHE} \tag{2}\]  
\[\text{O}_{2}(\text{g})+4\text{H}^{+}+4\text{e}^{-}\rightarrow\text{2H}_{2} \text{O}\text{ E}^{0}=1.23\text{ vs. SHE} \tag{3}\]  
The electrodeposition process was first applied to wastewater treatment by [PERSON] et al. [2] and popularized by [PERSON]'s and [PERSON]'s groups since the nineties using carbon felt (CF) and gas diffusion electrodes (GDEs), respectively [3,4]. The use of carbon is attractive due to the characteristics of this material: it is cheap, has large surface area, is inert, and presents good conduction of the electrical current. Additionally, carbon materials prefer the two electron process instead the reduction of oxygen to produce H\({}_{2}\)O via 4 e\({}^{-}\)[5]. The graphite [6], sponges [7], carbon fibers [8] and the reticulated vitreous carbon (RVC) [9], are just some examples that have been used in these processes to produce H\({}_{2}\)O\({}_{2}\). Three dimensional porous electrodes, such as RVC have high specific surface area, which directly influences in acceptable densities of electrical currents [10]. The RVC has been widely used as cathode in the electrofenton process. For instance, [PERSON]'s reagent (Fe\({}^{2+}\)/H\({}_{2}\)O\({}_{2}\)) has been successfully produced electrochemically under mildly acidic solutions using RVC cathodes, permitting the oxidation of 1 kg of phenol at SnO\({}_{2}\)-coated Ti foam anodes with an associated electrical charge consumption of 6.3 kA h at 100 A m\({}^{-2}\)[11]. This was carried out by Fe\({}^{2+}\) ion addition or by reducing Fe\({}^{3+}\) ions electrochemically in the reactor with the simultaneous electrochemical production of H\({}_{2}\)O\({}_{2}\) via reduction of dissolved oxygen. Discolouration and mineralization of azo dyes such as orange-G can be performed using the electrofenton reaction at TiO\({}_{2}\) anodes via the generation of H\({}_{2}\)O\({}_{2}\) at RVC cathodes [12].