TiO2/UV Photodegradation of Azo Dyes in Aqueous Solutions

Tang, Walter Z.; Zhang, Z.; An, Hongze; Quintana, Mildred; Torres, Diaz

doi:10.1080/09593330.1997.9618466

Cited by 129 publications

(23 citation statements)

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“…This is because three possible reaction mechanisms can contribute to dye degradation, (1) hydroxyl radical attack, (2) direct oxidation by the positive hole, and (3) direct reduction by the electron in the conducting band. The contribution of each one depends on the substrate nature and pH (Tang et al 1997). The solution pH modifies the electrical double layer of the solid electrolyte interface, and consequently affects the sorption-desorption processes and the separation of the photogenerated electron-hole pairs in the surface of the semiconductor particles.…”

Section: Effect Of Phmentioning

confidence: 99%

Parameters affecting the photocatalytic degradation of dyes using TiO2: a review

2015

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Traditional chemical, physical and biological processes for treating wastewater containing textile dye have such disadvantages as high cost, high energy requirement and generation of secondary pollution during treatment process. The advanced oxidation processes technology has been attracting growing attention for the decomposition of organic dyes. Such processes are based on the light-enhanced generation of highly reactive hydroxyl radicals, which oxidize the organic matter in solution and convert it completely into water, CO 2 and inorganic compounds. In this presentation, the photocatalytic degradation of dyes in aqueous solution using TiO 2 as photocatalyst under solar and UV irradiation has been reviewed. It is observed that the degradation of dyes depends on several parameters such as pH, catalyst concentration, substrate concentration and the presence of oxidants. Reaction temperature and the intensity of light also affect the degradation of dyes. Particle size, BETsurface area and different mineral forms of TiO 2 also have influence on the degradation rate.

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Section: Effect Of Phmentioning

confidence: 99%

Parameters affecting the photocatalytic degradation of dyes using TiO2: a review

2015

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“…Three mechanisms have been proposed to account for dye degradation: hydroxyl-radical attack; direct oxidation by positive holes (hv B + ); and direct reduction by conduction-band electrons (e CB -). All of these mechanisms are highly dependent on substrate nature and pH (Tang et al 1997).…”

Section: Effect Of Phmentioning

confidence: 99%

Evaluation on the Photocatalytic Degradation Activity of Reactive Blue 4 using Pure Anatase Nano-TiO2

Samsudin

Sze²,

Ta³

et al. 2015

JSM

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“…To treat textile wastewater containing azo dyes, one objective is to decolorize recalcitrant azo dyes by destroying the chromophore azo bond to improve its biodegradability. Our previous studies reported that azo bonds could be oxidized efficiently by UV/TiO 2 or H 2 O 2 / iron powder system (Tang and Chen 1996;Tang et al 1997). After the azo bond was destroyed, the intermediates would be easier to be biodegraded.…”

Section: Introductionmentioning

confidence: 99%

Degradation of Acid Blue 161 by Fenton and photo-Fenton processes

Trovó

Hassan²,

Sillanpää

et al. 2015

Int. J. Environ. Sci. Technol.

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Degradation kinetics of azo dye, Acid Blue 161 (AB161), by Fenton and photo-Fenton processes in aqueous solution was investigated. At pH 3.5, the effects of H 2 O 2 , Fe 2? , and H 2 O 2 /Fe 2? molar ratios, on the AB161 decolorization kinetic rates, were evaluated. Experimental results confirmed that the optimal H 2 O 2 /Fe 2? molar ratio of 12 is close to the theoretical value of 11 as predicted by previously developed model. The influence of azo bond loading (L azo bond ), from 0.25 to 1.0, and pH values from 2.5 to 4.0 were evaluated on AB161 decolorization kinetic rates. A correlation between the natural logarithm of the decolorization rates and L azo bond was established at the different pH values. The decolorization rate increased linearly with decreasing L azo bond , in the order of pH: 3.5 [ 3.0 [ 2.5 [ 4.0. UV radiation of Fenton processes increases degradation of AB161 more than 40 % due to the regeneration of Fe 2? through photo-catalytic reactions. This phenomenon was confirmed by measuring H 2 O 2 concentration during the photo-Fenton processes. The results suggest that Fenton processes can effectively decolorize or degrade wastewater containing azo dye, AB161. Photo-Fenton processes may further increase the degradation efficiency of AB161 by 40 %.

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TiO2/UV Photodegradation of Azo Dyes in Aqueous Solutions

Cited by 129 publications

References 0 publications

Parameters affecting the photocatalytic degradation of dyes using TiO2: a review

Parameters affecting the photocatalytic degradation of dyes using TiO2: a review

Evaluation on the Photocatalytic Degradation Activity of Reactive Blue 4 using Pure Anatase Nano-TiO2

Degradation of Acid Blue 161 by Fenton and photo-Fenton processes

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