Photoactivity of boron-or nitrogen-modified TiO2 for organic pollutants degradation: Unveiling the photocatalytic mechanisms and by-products

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Moreira, Ailton. J. ; dos Santos, Barbara R. M. ; Dias, Jeferson A. ; Rabello, Pietra T. ; Coelho, Dyovani ; Mascaro, Lucia H. ; Freschi, Gian P. G. ; Gobato, Yara G. ; Galeti, Helder V. A. ; Mastelaro, Valmor R. ; Pereira, Ernesto Chaves

• Document type: Journal article
• Source: JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING; v. 11, n. 1, p. 12-pg., 2022-12-30.

Abstract

The degradation of fluoxetine (FLX) emerging pollutant and the formation of by-products, potentially present in environmental ecosystems, was investigated from photocatalytic processes. Applying different synthesis methods, nitrogen (TiN) or boron (TiB)-modified TiO2 presented oxygen vacancies (Vo & BULL;) responsible for generating intermediate energy levels, which acted as shallow traps to minimize the recombination processes and maintain the efficient separation of charge carriers. All photocatalysts showed the potential to produce hydroxyl radicals (& BULL;OH) from the oxidation of water in h+(VB), achieving 100% of RhB degradation under UV or visible irradiation. For the degradation of FLX, an alternative mechanism mediated by one of the by-products was confirmed after LC-MS-Q-TOF analysis. The protonation, dehalogenation and hydroxylation steps of FLX (m/z [H+] =310.1419) produce the transformation products TP8 (m/z[H+] = 310.1430), TP6 (m/z[H+] = 286.1454), and TP9 (m/z = 161.0221 (-ESI)), respectively. Other by-products have been identified after photodegradation, and their presence in FLX-contaminated ecosystems cannot be ignored. Therefore, high-performance photocatalysts obtained in this study are real alternatives for the environmental remediation of organic pollutants in aquatic ecosystems. (AU)

• 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: 16/20609-8 - Mult-user equipment approved in the grant 2014/50249-8: ultra-performance liquid chromatography with supercritical CO2 and mass detector
• Grantee: Arlene Gonçalves Corrêa
• 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