Toward the Development of a Novel Electro-Fenton System for Eliminating Toxic Organic Substances from Water. Part 2. Preparation, Characterization, and Evaluation of Iron-Impregnated Carbon Felts as Cathodic Electrodes

Abstract

New results are presented on the preparation and performance of iron-impregnated carbon electrodes for a novel electro-Fenton "filter"-type device, reported in a previous publication. Two composite Fe/carbon-felt electrodes were prepared via different procedures: one prepared under oxidizing conditions (i.e., dissolved oxygen) through immersion of carbon felt in an iron ethanolic solution (CF m -Fe), and another prepared under reduced oxidative conditions (nitrogen, ammonia, etc.) leading to in situ formation of iron nanoparticles on the carbon surface (CF m -nFe). The cathodes were characterized by X-ray diffraction (XRD), N 2 adsorption−desorption (BET), scanning electron microscopy (SEM), Raman microspectroscopy, and linear sweep voltammetry (LSV). The stability and oxidation performance of these electrodes were evaluated by measuring the leaching of iron species and the degradation in aqueous medium of a common pharmaceutical compound (diclofenac), respectively. The results show that the flow-through operation leads to increased solute removal, attributed to the enhanced electrosorption on the charged electrodes and the synergistic degradation/mineralization of diclofenac due to Fenton reactions on the composite cathodes. The CF m -nFe composite cathode was the most stable, exhibiting high sorption capacity (59.2 mg DCF g CFm −1) and significant degradation/mineralization efficiency (63.7 and 31.6%, respectively) at low applied potential (1.0 V/Ag/AgCl), neutral pH and high initial pollutant concentration (∼34 mg L −1 ). The results demonstrate the capability of the electro-Fenton process, implemented in the novel "filter"-type device, to decontaminate neutral waters polluted by diclofenac and similar organic compounds with no addition of chemicals and with reduced energy expenditure. Research and development (R&D) needs are also outlined.

Bio-electro-Fenton process for the degradation of Non-Steroidal Anti-Inflammatory Drugs in wastewater

“…[48,[50][51][52][53][54][55]. Thus, experiments were performed with real wastewater aftersecondary biological treatment (Lyngby Wastewater Treatment Plant, Copenhagen, Denmark) for the degradation of the NSAIDs compounds.…”

Tratamiento Electroquímico De Una Emulsión Acuosa De Ácido Palmítico Empleando Un Electrodo De Fieltro Grafítico Modificado Con Hierro

“…Los procesos avanzados de oxidación (PAO) ofrecen métodos muy eficaces para degradar contaminantes en medios acuosos [1][2][3][4][5][6][7] . Entre ellos, se destaca el método electro-Fenton, donde el peróxido de hidrógeno se genera catódicamente y luego se convierte catalíticamente por Fe(II) en radicales con alto poder oxidante 2,[5][6][7] .…”

“…Los procesos avanzados de oxidación (PAO) ofrecen métodos muy eficaces para degradar contaminantes en medios acuosos [1][2][3][4][5][6][7] . Entre ellos, se destaca el método electro-Fenton, donde el peróxido de hidrógeno se genera catódicamente y luego se convierte catalíticamente por Fe(II) en radicales con alto poder oxidante 2,[5][6][7] . Varios estudios han demostrado la gran capacidad de estos radicales para degradar compuestos orgánicos como productos farmacéuticos, colorantes, pesticidas, compuestos aromáticos, fenoles, ácidos carboxílicos, etc., que son altamente resistentes al tratamiento con métodos convencionales 2,[5][6][7] .…”

“…Entre ellos, se destaca el método electro-Fenton, donde el peróxido de hidrógeno se genera catódicamente y luego se convierte catalíticamente por Fe(II) en radicales con alto poder oxidante 2,[5][6][7] . Varios estudios han demostrado la gran capacidad de estos radicales para degradar compuestos orgánicos como productos farmacéuticos, colorantes, pesticidas, compuestos aromáticos, fenoles, ácidos carboxílicos, etc., que son altamente resistentes al tratamiento con métodos convencionales 2,[5][6][7] . Entre los contaminantes presentes en las aguas residuales, el tratamiento de ácidos grasos provenientes de diferentes tipos de industria, como alimentos, acuicultura, pesca, etc., representan un serio problema ambiental [8][9][10] .…”

Electrical activation of hydrogen peroxide for organic contaminant degradation using an improved gas diffusion cathode

“…Electrochemical advanced oxidation processes, (EAOPs) are considered environmentally friendly emerging alternatives for the abatement of pollution caused by a multitude of organic micro pollutants in waters [1]. Among EAOPs, Electro-Fenton process is one of the most widely used in situ electrochemical technology to control pollution through redox processes involving either direct oxidation, or through synergistic systems based on the power of an oxidant species generated in situ [2].…”