Dye Degradation Enhanced by Coupling Electrochemical Process and Heterogeneous Photocatalysis

• Autor(a) principal: Santos,Lidiaine M.
• Data de Publicação: 2015
• Outros Autores: Amorim,Kamila P. de, Andrade,Leonardo S., Batista,Paulo S., Trovó,Alam G., Machado,Antonio E. H.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532015000901817
• topic: azo dyes; advanced oxidation processes; discoloration; mineralization; titanium dioxide

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.