Environmental application of ti/tio2 anodes prepared by dc-magnetron sputtering: degradation of acid orange 7

Susana Serio1, Lu s Carlos Silva1, Maria Estrela Melo Jorge2, Silvio Ferreira3, Lurdes Ciriaco3, Maria Jose Pacheco3, Ana Lopes3

1 CEFITEC, Departamento de F sica, Faculdade de Ci ncias e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
2 Centro de Qu mica e Bioqu mica, Faculdade de Ci ncias, Universidade de Lisboa, 1749-016 Lisboa, Portugal
3 FibEnTech-UBI and Department of Chemistry, Universidade da Beira Interior, 6201-001 Covilh , Portugal

Abstract


Ti/TiO2 films were prepared by DC reactive magnetron sputtering followed by annealing in air at 400 C for 4 h. Structural tests have been performed to characterize the films, showing that the prepared films present 70% of anatase phase. When these results are compared with those from TiO2 films grown on glass substrates with similar deposition parameters, it can be seen that Ti substrates favour the formation of rutile phase, which is not observed on the films supported on glass, indicating that the film structure is strongly influenced by the substrate's nature. The electrocatalytic oxidation of acid orange 7 aqueous solutions, with concentrations between 5 and 50 mg L-1, was performed using Ti/TiO2 electrodes, at applied current densities of 0.1 and 0.25 mA cm-2. COD removal increased with applied current density and acid orange 7 initial concentration. The current efficiency also increased with initial concentration, showing that the process was mainly controlled by diffusion.

Keywords


acid orange 7; DC-magnetron sputtering; decolourization; electrodegradation; TiO2

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