CeO₂ photoanode for efficient degradation of ciprofloxacin: optimization and mechanism

Author(s)

Molina-Lozano, A. E. ; Souto, Robson S. ; Colombo, Renata ; Lanza, Marcos. R. V. ; Ortiz, Pablo ; Cortes, Maria T.

• Document type: Journal article
• Source: Journal of Applied Electrochemistry; v. N/A, p. 18-pg., 2025-01-03.

Abstract

Emerging contaminants pose significant public health risks, highlighting the need for effective water decontamination technologies. Cerium dioxide (CeO2) is a promising photoanode for degrading organic pollutants in photoelectrochemical systems due to its favorable physicochemical properties, environmental friendliness, and recyclability. Despite encouraging findings, further research is needed on CeO2's role in degrading pharmaceutical contaminants. In this study, CeO2 photoanodes were obtained and evaluated in the photoelectrochemical degradation of ciprofloxacin (Cip) in aqueous media. The photoanode was synthesized by electrodeposition followed by annealing to obtain it as an immobilized layer on a glass substrate (FTO). CeO2 was characterized for its optoelectronic, photoelectrochemical, structural, and morphological properties using RAMAN, XRD, XPS, UV-Vis, zeta potential, LSV, CA, EIS, and SEM, revealing a mixed valence composition (Ce4+/Ce3+), negative surface charge, and UV absorption. The effects of pH, ciprofloxacin concentration, and anodic polarization potential on degradation efficiency were assessed in a three-electrode photoelectrochemical cell. Radical scavengers (isopropyl alcohol, benzoquinone, and ammonium oxalate) revealed hydroxyl radicals (OH center dot) as the primary species responsible for degradation. The photoelectrochemical process showed a maximum efficiency of 65.8% at pH 9, [ciprofloxacin] = 5.0 mg L-1, and + 2.0 V (vs. Ag/AgCl), while in synthetic wastewater, the efficiency increased to 89.7%. This study enhances understanding of CeO2's functionality and mechanism as a photoanode for ciprofloxacin degradation. (AU)

• FAPESP's process: 20/02743-4 - Fe/RuO2-TiO2 films supported on carbon felt for norfloxacin degradation by heterogeneous electro-fenton process
• Grantee: Géssica de Oliveira Santiago Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/22210-0 - EMU granted in process 2017/10118-0: liquid chromatograph (HPLC)
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 19/06650-3 - EMU granted in the 2017/10118-0 process: potentiostat system with impedance module
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 18/22022-0 - EMU granted in the 2017/10118-0 process: spectroelectrochemistry system
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 16/19612-4 - Degradation of endocrine disruptors carbofuran, methylparaben and propylparaben via electrogenerated H2O2 and associated processes (electrogenerated H2O2/UV, electro-Fenton e photoelectro-Fenton)
• Grantee: Paulo Jorge Marques Cordeiro Junior
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/22211-7 - EMU granted in process 2017/10118-0: total organic carbon analyzer (TOC)
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program