Electro-Fenton treatment of benzophenone-4 solutions: A sustainable approach for its removal using an air-diffusion cathode

Author(s)

Fernandes, Caio Machado ; Brillas, Enric ; Santos, Mauro C. ; Garcia-Segura, Sergi

• Document type: Journal article
• Source: PROCESS SAFETY AND ENVIRONMENTAL PROTECTION; v. 199, p. 11-pg., 2025-07-01.

Abstract

This work reports the efficient degradation and mineralization of benzophenone-4 (BP-4), a widely used UV filter associated with endocrine-disrupting effects, via the electro-Fenton process. Key operating parameters including pH, current density, Fe2 + dosage, and initial pollutant concentration were optimized. At pH = 3.0, the best performance was obtained. Under optimum conditions of 20 mA cm- 2 and 0.75 mM Fe2+, complete BP-4 degradation was achieved in remarkably short times: 2 min for 1-2.5 mg L-1, 3 min for 5 mg L-1, 4 min for 10 mg L-1, 5 min for 20 mg L-1, and 7 min for 40 mg L-1. Total mineralization was reached for low concentration of 1 mg L-1, varying between 77 % and 90 % for higher loads up to 40 mg L-1. The reaction followed pseudo-first-order kinetics, with high apparent rate constant of 0.641 min- 1 for 40 mg L- 1 and lower energy consumption of 0.261 kWh (g TOC)-1. Radical quenching experiments with TBA confirmed that physisorbed BDD(center dot OH) and homogeneous center dot OH were the predominant oxidants. Persistent carboxylic acid by-products, in the form of Fe3+ complexes, were the only residues after 180 min of treatment, readily being biodegradable. The process demonstrates high efficiency across a broad range of BP-4 concentrations, offering a viable solution for its removal from contaminated waters. (AU)

• FAPESP's process: 24/03549-8 - Innovative Electrochemical Reactor Design for Pollutants Removal through Solar Photoelectro-Fenton
• Grantee: Caio Machado Fernandes
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 22/10484-4 - Application of low-cost nanomaterials for degradation of endocrine disruptors through advanced electrochemical oxidation processes under the influence of a magnetic field
• Grantee: Caio Machado Fernandes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• 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: 22/15252-4 - Nanostructured electrocatalysts for application in direct alkaline-acid fuel cells of glycerol
• Grantee: Mauro Coelho dos Santos
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants