Optimised photocatalytic degradation of a mixture of azo dyes using a TiO2/H2O2/UV process.

Autor: Palácio, Soraya Moreno, Espinoza-Quiñones, Fernando Rodolfo, Módenes, Aparecido Nivaldo, Manenti, Diego Ricieri, Oliveira, Cláudio Celestino, Garcia, Juliana Carla
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Zdroj: Water Science & Technology; 2012, Vol. 65 Issue 8, p1392-1398, 7p
Abstrakt: The aim of the present study was to optimise the photocatalytic degradation of a mixture of six commercial azo dyes, by exposure to UV radiation in an aqueous solution containing TiO2-P25. Response surface methodology, based on a 3² full factorial experimental design with three replicates was employed for process optimisation with respect to two parameters: TiO2(0.1-0.9 g/L) and H2O2 (1-100 mmol/L). The optimum conditions for photocatalytic degradation were achieved at concentrations of 0.5 g TiO2/L and 50 mmol H2O2/L, respectively. Dye mineralisation was confirmed by monitoring TOC, conductivity, sulfate and nitrate ions, with a sulfate ion yield of 96% under optimal reactor conditions. Complete decolorisation was attained after 240 min irradiation time for all tested azo-dyes, in a process which followed a pseudo-first kinetic order model, with a kinetic rate constant of approximately 0.018 min-1 . Based on these results, this photocatalytic process has promise as an alternative for the treatment of textile effluents. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index