Dye Degradation Enhanced by Coupling Electrochemical Process and Heterogeneous Photocatalysis

AUTOR(ES)

Santos, Lidiaine M., Amorim, Kamila P. de, Andrade, Leonardo S., Batista, Paulo S., Trovó, Alam G., Machado, Antonio E. H.

FONTE

J. Braz. Chem. Soc.

DATA DE PUBLICAÇÃO

2015-09

RESUMO

In this study, we evaluated the combination between an electrochemical process, occurring in the dark, and a heterogeneous photocatalytic process for dye degradation, using the azo dye tartrazine as model of oxidizable substrate. TiO2 P25 and an Ag-doped TiO2 were used as photocatalysts in suspensions containing 50 mg L–1 of tartrazine. The best result, 74% of dye mineralization in 120 min of reaction, was obtained using TiO2 P25 as photocatalyst and a current density of 10 mA cm–2 in the electrochemical cell, a value 30% higher than the sum of the results obtained by heterogeneous photocatalysis (44%) and electrochemical oxidation (13%). The use of Ag-doped TiO2 did not result in significant improvement on tartrazine mineralization, due to the aggregation of these nanoparticles. Our results suggest that this process can be an alternative for a complete treatment (discoloration and mineralization) of tartrazine and most likely other azo dyes.

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