Résumé
A new composite material has been developed for the electro-Fenton process to remove Acid Orange 7 (AO7), an azo dye pollutant, from wastewater. This material features the in situ growth of carbon nanotubes (CNT) at the interface of carbon felt/phenolic resin (CF/PR). Different CF/PR composite materials were manufactured by impregnation of an alcoholic phenolic resin/ferrocene solution on a carbon felt that was treated by acidic oxidation or not. The carbonization step under N2 atmosphere is necessary for the growth of the CNTs at the interface of the CF/PR composite. SEM observations show clearly the presence of CNTs at different levels of growth at the interface CF/PR. They also reveal that oxidizing carbon felts greatly boosts the CNT production in the composite (CF-oxy/CNT/PR). Raman spectroscopy, using the ID/IG ratio, confirmed these findings, matching the conductivity measurements. The formation of CNT via a ferrocene catalyst at the CF/PR interface notably enhanced the composite electrode's conductivity, especially when the carbon felts were oxidized. The elaborated composites were further used as cathodes to carry out the electro-Fenton (EF) process applied to the degradation of Acid Orange 7 (AO7) in the treated effluent. The discoloration of the AO7 solution was achieved in <15 min, demonstrating an effective treatment. In addition, the progress of AO7 mineralization was tracked through measurements of total organic carbon (TOC). Therefore, after 4 h of electro-Fenton treatment, a significant enhancement was evidenced with nearly a complete mineralization of 98 % compared to only 55 % achieved with the raw carbon felt (CF) material as electrode. As a result, the proposed method of modifying the CF/PR composite interface through CNT growth has improved their electrocatalytic activities, showcasing their promising potential for electrochemical applications.
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•Ferrocene powder was used as catalyst for carbon nanotubes (CNTs) growth.•Electrochemical degradation of azo dye using CNT-modified carbon felt cathode.•Carbon felt modified with carbon nanotubes present excellent electroactive activity.•Outstanding performance of electro-Fenton process for wastewater treatment.•Carbon cathode exhibited high electrochemical performance and long-term stability.