Photoelectrocatalytic production of active chlorine on nanocrystalline titanium dioxide thin-film electrodes
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Data
2004-06-01
Autores
Zanoni, Maria Valnice Boldrin [UNESP]
Sene, Jeosadaque J.
Selcuk, Huseyin
Anderson, Marc A.
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Resumo
The production of chlorine and hypochlorite is of great economical and technological interest due to their large-scale use in many kinds of commercial applications. Yet, the current processes are not without problems such as inevitable side reactions and the high cost of production. This work reports the photoelectrocatalytic oxidation of chloride ions to free chlorine as it has been investigated by using titanium dioxide (TiO2) and several metal-doped titanium dioxide (M-TiO2) material electrodes. An average concentration of 800 mg L-1 of free chlorine was obtained in an open-air reactor using a TiO2 thin-film electrode biased at +1.0 V (SCE) and illuminated by UV light. The M-doped electrodes have performed poorly compared with the pure TiO2 counterpart. Test solutions containing 0.05 mol L-1 NaCl pH 2.0-4.0 were found to be the best conditions for fast production of free chlorine. A complete investigation of all parameters that influence the global process of chlorine production by the photoelectrocatalytic method such as applied potential, concentration of NaCl, pH solution, and time is presented in detail. In addition, photocurrent vs potential curves and the reaction order are also discussed.
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Palavras-chave
Catalysis, Catalytic converters, Curve fitting, Electrochemical electrodes, pH effects, Photochemical reactions, Reaction kinetics, Active chlorine, Photoelectrocatalytic production, Thin film devices, chlorine, sodium chloride, titanium dioxide, electrochemistry, catalysis, chemical reaction, crystallization, electric current, electrode, electrolysis, film, illumination, oxidation, parameter, photoreactivation, reaction analysis, ultraviolet radiation, Chlorides, Chlorine, Conservation of Natural Resources, Crystallization, Electrochemistry, Electrodes, Hypochlorous Acid, Ions, Nanotechnology, Oxidation-Reduction, Photochemistry
Como citar
Environmental Science and Technology, v. 38, n. 11, p. 3203-3208, 2004.