Influence of oxygen vacancies, surface composition, and crystallite size on the photoelectrochemical oxidation activity of C,N-codoped TiO 2 for cefadroxil abatement along with O 3 .

Autor:	Palomares-Reyna D; Centro Mexicano para la Producción más Limpia, Instituto Politécnico Nacional, Av. Acueducto s/n, Col. La Laguna Ticomán, Ciudad de México, 07340, Mexico; Centro de Investigación y Desarrollo Tecnológico en Electroquímica, Parque Sanfandila s/n, Pedro Escobedo, 76703, Santiago de Querétaro, Mexico., Palomino-Resendiz RL; Centro Mexicano para la Producción más Limpia, Instituto Politécnico Nacional, Av. Acueducto s/n, Col. La Laguna Ticomán, Ciudad de México, 07340, Mexico., García-Pérez UM; Universidad Autonoma de Nuevo Leon, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria Km 2.3, C.P. 66600, Apodaca, N.L., Mexico., Fuentes-Camargo I; Ing. Química Ambiental, ESIQIE-Instituto Politécnico Nacional, Zacatenco, Ciudad de México, 07738, Mexico., Lartundo-Rojas L; Centro de Nanociencias y Micro Nanotecnologías-Instituto Politécnico Nacional, Luis Enrique Erro s/n, U. P. Adolfo López Mateos, Ciudad de México, 07738, Mexico., Sosa-Rodríguez FS; Research Area of Growth and Environment, Metropolitan Autonomous University, Azcapotzalco (UAM-A), Av. San Pablo 180, Mexico City, 02200, Mexico., Vilar VJP; Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering (ALiCE), Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal., Vazquez-Arenas J; Centro Mexicano para la Producción más Limpia, Instituto Politécnico Nacional, Av. Acueducto s/n, Col. La Laguna Ticomán, Ciudad de México, 07340, Mexico. Electronic address: jorge_gva@hotmail.com.
Jazyk:	angličtina
Zdroj:	Chemosphere [Chemosphere] 2023 Nov; Vol. 342, pp. 140133. Date of Electronic Publication: 2023 Sep 11.
DOI:	10.1016/j.chemosphere.2023.140133
Abstrakt:	This study aims the development of photoelectrodes to be incorporated in a photoelectrocatalytic ozonation (PECO) process for tertiary treatment of urban wastewaters, targeting the removal of contaminants of emerging concern (CEC). PECO tests were performed using urban wastewater after secondary treatment fortified with Cefadroxil (CFX, C 16 H 17 N 3 O 5 S), as target model CEC. Three Nitrogen and Carbon doped TiO 2 (CN-TiO 2 ) electrodes were synthesized by anodizing at 50, 70, and 90 V, and calcined. These materials were characterized by X-Ray diffraction and Rietveld refinement, Scanning Electron Microscopy, Diffuse Reflectance Spectroscopy, X-ray photoelectron spectroscopy, chronoamperometry, and electrochemical impedance spectroscopy, to correlate defects with photoactivity. All photoanodes considerably reduced their main bandgaps by the incorporation of C and N species, to enable absorption capacities in the UV region using a Xe lamp. The lowest oxygen vacancy content and largest crystallite size were found for CN-TiO 2 -70, favoring the reduction of bulk defects that could act as recombination of charge carriers. Therefore, oxygen vacancies affect more the TiO 2 photoactivity compared to the crystallite size or the light absorption capacity, confirming that a lower content of vacancies in the material bulk and surface doping significantly influence the activity as detected by Rietveld refinement, DRS, and XPS. The electrochemical techniques confirm that the highest photocurrent was obtained for CN-TiO 2 -70, whence this photoanode was chosen to carry out the CFX degradation. A point defect model simulating Nyquist plot reveals that the photoactivity depends on the speed to diffuse oxygen vacancies through the TiO 2 coating. All abatement processes were followed by high-performance liquid chromatography, and Total Organic Carbon (TOC). At neutral and alkaline conditions, CFX is eliminated to levels below the analytical detection limit after 90 min of treatment (TOC removals of 87 and 91%, respectively), indicating that the coupling between the CN-TiO 2 -70 photocatalyst and ozone is effective in eliminating the contaminant due to parallel routes forming • OH species. Lower CFX degradation observed at acidic pH (TOC removal of 70%) is assigned to the difficulty of oxidizing protonated CFX species. Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. (Copyright © 2023 Elsevier Ltd. All rights reserved.)
Databáze:	MEDLINE
Externí odkaz:	Full Text from ScienceDirect