WO₃/BiVO₄ heterojunctions: Photoelectrochemical performance for dexamethasone degradation and toxicity assessment in Lactuca sativa

Author(s)

Reis, Roberta Y. N. ; Gonzaga, Isabelle M. D. ; Goncalves, Roger ; Fernandes, Carlos H. M. ; Assis, Marcelo ; Pereira, Ernesto C. ; Lanza, Marcos R. V. ; Mascaro, Lucia H.

• Document type: Journal article
• Source: Electrochimica Acta; v. 526, p. 15-pg., 2025-06-20.

Abstract

Water contamination by dexamethasone (DEX) poses a significant threat to the global population. Developing an effective and affordable system for DEX removal remains a critical need, particularly in treating DEX and other contaminants at environmentally relevant concentrations. Chemical bath and spin coating techniques were applied to synthesize a custom-designed WO3/BiVO4 interface electrode on a fluorine-doped tin oxide (FTO) substrate. Each WO3/BiVO4, WO3, and BiVO4 layer was characterized both photochemically and electrochemically to identify enhanced light harvesting and electron transfer at the heterojunction. Compared to the pristine materials, more charge carriers, enhanced transfer, and separation of photogenerated pairs were observed. The effectiveness of the WO3/BiVO4 electrode in removing 10 mg L-1 DEX was evaluated under photolysis, electrocatalysis (EC), and photoelectrocatalysis (PhEC) treatment conditions. The PhEC treatment at 1 mA cm(-2) under visible light irradiation exhibited an excellent DEX removal efficiency of 100 %, surpassing photocatalysis (54 %) and EC (14.6 %). The mineralization rate and the formation of short-chain acids (oxalic, succinic, glycolic, and adipic) depended on the processes investigated. The large formation of superoxide radicals from the photogenerated charges in WO3/BiVO4 was revealed by scavenger tests, elucidating the degradation mechanism in PhEC, which resulted in a final product with lower toxicity, proven by tests with Lactuca sativa. The application of reuse cycles and characterizations after the PhEC processes demonstrated the electrode's good quality and useful life. Therefore, it can be inferred that the WO3/BiVO4 electrode applied in the PhEC process efficiently removes DEX and presents itself as a promising proposal for treating residual drugs in environmental matrices. (AU)

• FAPESP's process: 21/11326-0 - Study of copper and copper oxide photoelectrodes for wastewater treatment after the COVID-19 pandemic
• Grantee: Roberta Yonara Nascimento Reis
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 23/06558-5 - Gas diffusion electrodes modified with Co and Fe NPs and biochar for the degradation of antidepressant drugs: mechanistic and technological aspects
• Grantee: Carlos Henrique Magalhães Fernandes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• 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: 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: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 20/15211-0 - Development of photo anodes g-C3N4/BiVO4 and g-C3N4/CuO applied in the photoelectrochemical degradation of effluents from the textile industry
• Grantee: Isabelle Maria Duarte Gonzaga
• 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: 23/08525-7 - Development of 3D marine collagen-based wound dressings enriched with functional nanoparticles for the regeneration of cutaneous wounds.
• Grantee: Marcelo de Assis
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country
• Grantee: Ana Flávia Nogueira
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• 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