Electrophotocatalysis on large scale nanotubular structured TiO2 electrodes for refrectory organics removal was assessed and optimized, using azo dyes as reference compounds. Catalyst was grown by anodic oxidation directly on Ti surface and characterized by SEM and XRD analyses. TiO2/Ti was used as photo-anode under UV radiation and subjected to bias in a 0.8 L batch reactor. Electrophotocatalysis was compared with photolysis and photocatalysis. The influence of some operating parameters was evaluated in photoelectrochemical tests conducted in a three-electrodes cell. The process was optimized using TiO2/Ti photocurrent intensity as an indicator for catalyst photoresponse. Improved reactor configuration (1.8 L) was used for the decolorization of azo dyes. Electrophotocatalysis was compared with P-25 Degussa TiO2 in slurry phase using the same surface of the immobilized catalyst. Synergistic effect was observed between photocatalysis and TiO2 bias. The effect of operating parameters was highlighted and a reactor optimized configuration permitted to achieve the complete decolorization of a 25 mg/L RR 243 (Reactive Red 243) solution in 60 minutes and its mineralization at 80% in 100 minutes. Electrophotocatalysis was proven to be more competitive than P-25 Degussa benchmark using same catalyst surface. Neither chemical reagents nor catalyst separation phases were required. TiO2/Ti showed good durability over process time, displaying constant performances.

Electrophotocatalytic Decolorization of Azo Dyes on TiO2 Self-Organized Nanotubes in a Laboratory Scale Reactor

TUROLLA, ANDREA;BESTETTI, MASSIMILIANO;ANTONELLI, MANUELA
2011-01-01

Abstract

Electrophotocatalysis on large scale nanotubular structured TiO2 electrodes for refrectory organics removal was assessed and optimized, using azo dyes as reference compounds. Catalyst was grown by anodic oxidation directly on Ti surface and characterized by SEM and XRD analyses. TiO2/Ti was used as photo-anode under UV radiation and subjected to bias in a 0.8 L batch reactor. Electrophotocatalysis was compared with photolysis and photocatalysis. The influence of some operating parameters was evaluated in photoelectrochemical tests conducted in a three-electrodes cell. The process was optimized using TiO2/Ti photocurrent intensity as an indicator for catalyst photoresponse. Improved reactor configuration (1.8 L) was used for the decolorization of azo dyes. Electrophotocatalysis was compared with P-25 Degussa TiO2 in slurry phase using the same surface of the immobilized catalyst. Synergistic effect was observed between photocatalysis and TiO2 bias. The effect of operating parameters was highlighted and a reactor optimized configuration permitted to achieve the complete decolorization of a 25 mg/L RR 243 (Reactive Red 243) solution in 60 minutes and its mineralization at 80% in 100 minutes. Electrophotocatalysis was proven to be more competitive than P-25 Degussa benchmark using same catalyst surface. Neither chemical reagents nor catalyst separation phases were required. TiO2/Ti showed good durability over process time, displaying constant performances.
2011
Advanced oxidation processes; Anodic oxidation; Bias; Photocatalysis; Titanium dioxide
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/667975
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