Using Au NPs anchored on ZrO2/carbon black toward more efficient H2O2 electrogeneration in flow-by reactor for carbaryl removal in real wastewater

Author(s)

Kronka, Matheus S. ; Fortunato, Guilherme V. ; Mira, Leticia ; Dos Santos, Alexsandro J. ; Lanza, Marcos R. V.

• Document type: Journal article
• Source: CHEMICAL ENGINEERING JOURNAL; v. 452, p. 14-pg., 2023-01-15.

Abstract

In the present study, we designed a highly efficient catalyst for H2O2 production using gold nanoparticles (Au NPs) anchored on hybrid substrate composed of ZrO2 and Printex L6 carbon (Au-ZrO2/PL6C). The higher selectivity of Au-ZrO2/PL6C (97%) toward H2O2 electrogeneration and its improved activity in terms of ORR onset potential (140 mV for more positive values) compared to Au/PL6C (80%) were attributed to the synergism between Au NPs anchored on ZrO2/PL6C hybrid support. The results obtained from the application of the catalysts for H2O2 generation on gas diffusion electrode (GDE) after 120 min of electrolysis reflected the following order of efficiency: PL6C (similar to 140 mg L-1) < ZrO2/PL6C (similar to 235 mg L-1) < Au/PL6C (similar to 374 mg L-1) < Au-ZrO2/ PL6C (similar to 600 mg L-1). Given that Au-ZrO2/PL6C exhibited the highest catalytic efficiency, this catalyst was employed for the removal of carbaryl (CBR) using different electrochemical advanced oxidation processes. The CBR degradation tests exhibited pseudo first-order kinetics, with the electro-Fenton (EF) and photoelectro-Fenton (PEF) processes recording the fastest removal kinetics (3.5 x 10(-2) s(-1) and 4.1 x 10(-2) s(-1), respectively). The PEF process exhibited the highest efficiency in terms of organic by-products mineralization; this was attributed to the additional photodecarboxylation of the Fe(III)-RCOOH complexes by UVC light. The aromatic by-products, short chain carboxylic acids, and ionic nitrogen species produced during the mineralization process contributed to the successful degradation of CBR. Apart from the analysis with synthetic water, the study also analyzed the treatment of urban wastewater spiked with CBR using a pre-pilot flow plant. (AU)

• FAPESP's process: 19/20634-0 - Treatment of wastewater contaminated with endocrine interferences through the application of electrochemical advanced oxidation processes: synergistic effect of different carbon supported cathodes
• Grantee: Alexsandro Jhones dos Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/23464-3 - Study of agrochemical degradation paraquat, sodium-metham and carbaryl by Electrochemical Advanced Oxidation Process (EAOP) using gas diffusion electrode modified with bimetallic oxides
• Grantee: Matheus Schiavon Kronka
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 14/50945-4 - INCT 2014: National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactivies
• Grantee: Maria Valnice Boldrin
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/10118-0 - Study and application of electrochemical technology for the analysis and degradation of endocrine interferents: materials, sensors, processes and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 19/04421-7 - Production and characterization of metal-graphene or graphene oxide nanocomposites for the electrocatalytic production of hydrogen peroxide: Application to the degradation of endocrine disrupting chemicals by electrochemical advanced oxidation processes
• Grantee: Guilherme Vilalba Fortunato
• Support Opportunities: Scholarships in Brazil - Post-Doctoral