Application of Graphene and Carbon Nanotubes on Carbon Felt Electrodes for the Electro-Fenton System

Abstract

The electro-Fenton system has the ability to degrade wastewater and has received attention from many researchers. Currently, the core development objective is to effectively increase the degraded wastewater decolorization efficiency in the system. In this study, to improve the electro-Fenton system reaction rate and overall electrical properties, we used polyvinylidene difluoride to fix carbon nanotubes (CNTs) and graphene onto the system cathode (carbon felt electrode), which was then used to process Reactive Black 5 wastewater. Furthermore, we (1) used scanning electron microscopy to observe the structural changes in the electrode surface after modification; (2) used the Tafel curve to determine the electrode corrosion voltage and corrosion rate; and (3) analyzed the azo-dye decolorization level. The results showed that the maximum system decolorization rates of the CNT- and graphene-modified carbon felt electrodes were 55.3% and 70.1%, respectively. These rates were, respectively, 1.2 and 1.5 times higher than that of the unmodified carbon felt electrode, implying that we successfully improved the cathode characteristics. The modified electrode exhibited an improved conductivity and corrosion resistance, which, in turn, improved the system decolorization efficiency. This significantly increased the electro-Fenton system overall efficacy, making it valuable for future applications.

Graphene-Modified Composites and Electrodes and Their Potential Applications in the Electro-Fenton Process

“…In several papers polytetrafluroethylene (PTFE), a synthetic fluropolymer with good adhesion and lubricating properties, has been used successfully [55,56]. Spin coating has also been employed to deposit GO from slurries [57], while in some cases, the treated carbon or graphite felt is immersed in the rGO containing suspension or slurry [4], or dip-coated [58,59]. The solution or slurry coating approaches enable the addition of various additives that have the potential to enhance the removal of micropollutants using E-Fenton.…”

“…In most of these approaches, the graphene-modified electrode is compared to the conducting carbon or graphite felt or carbon cloth substrate electrodes and the addition of rGO clearly enhances the rate of H 2 O 2 generation to give a more efficient removal of the contaminants. Interestingly, it was shown by Wang et al [57], who employed polyvinylidene difluoride to fabricate both carbon nanotube (CNT) modified felt and graphene-modified felt electrodes, that the graphene-modified carbon felt was superior in the degradation of an azo dye molecule, reaching degradation rates of 70.1%, compared to the lower rates of 55.3% evident with the CNT-modified electrode. While both modifications enhanced the azo dye degradation rate compared to the untreated carbon felt electrode, the graphene-modified electrode produced a higher quantity of H 2 O 2 .…”

“…Bridged N-doped graphene and CNT composites, with microscopic three-dimensional structures, have been employed as gas diffusion electrodes and have been shown to enhance the oxygen reduction reaction, compared to graphene-based electrodes, CNT and graphite [98]. Other approaches include binder-free CNTs and graphene-based aerogel electrodes [89], iron oxide-containing CNTs, graphene-based aerogels [85] and graphene combined with CNTs on carbon felt electrodes [57]. In each of these cases, the addition of CNTs has been shown to be beneficial and to enable the more efficient removal of the contaminants.…”

3D Self-Supported Nitrogen-Doped Carbon Nanofiber Electrodes Incorporated Co/CoOx Nanoparticles: Application to Dyes Degradation by Electro-Fenton-Based Process

“…Metal/metal oxide NPs on the carbon electrode surface can be used as heterogeneous catalysts for the local generation of H 2 O 2 during the electro-Fenton oxidation process. Graphite [24], graphenes [25], carbon nanotubes [26], carbon nanofibers [27], carbon sponges [28], and carbon felts [14] are among the electrode materials with good conductivity investigated for the electrochemical production of H 2 O 2 . On the other hand, Fe 3+ sludge formation, due to the production of Fe 3+ , and the need for acidic pH (pH 2-4) for the electro-Fenton process can be solved by the mobilization of metal NPs (electrocatalyst) to overcome the narrow pH range required for the homogeneous electro-Fenton oxidation.…”

Enhancement of performance for graphite felt modified with carbon nanotubes activated by KOH as Cathode in electro-fenton systems

“…Based on the findings of this experiment, graphene-modified carbon felt cathodes could increase treatment efficiency by approximately 14% compared to CNT-modified carbon felt cathode. 12 However, it is not easy to mass-produce high-quality graphene at the moment and doing so will increase the cost of EF systems.…”