Photodegradation of surfactants. 11. .zeta.-Potential measurements in the photocatalytic oxidation of surfactants in aqueous titania dispersions

Zhao, Jincai; Hidaka, Hisao; Takamura, Akira; Pelizzetti, Ezio; Serpone, Nick

doi:10.1021/la00031a008

Cited by 129 publications

(77 citation statements)

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“…The carboxylate group can easily be adsorbed onto the surface of TiO 2 , because the latter are positively charged in acidic media. [36] Although the sterically bulky xanthene ring (see RhB structure above) somewhat hampers the negatively charged group from reaching the TiO 2 surface particles, a slight red-shift (~1 nm in 2 g L À1 TiO 2 ) of the absorption maximum was observed upon addition of colloidal TiO 2 . This indicates that the interaction between TiO 2 and the dye is relatively weak.…”

Section: Interactions Between the Photocatalyst (Siw 12 O 40mentioning

confidence: 99%

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO₂ Dispersions under Visible‐Light Irradiation: Mechanistic Implications

Chen

Zhao

Lei

et al. 2004

Chemistry A European J

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296

185

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This article examines the photoxidation of a dye (rhodamine‐B, RhB) by visible‐light irradiation in the presence of a polyoxometalate (12‐tungstosilicic acid, H4SiW12O40), and compares it with the analogous process in the presence of TiO2. The photoreaction processes were examined by UV‐visible spectroscopy, fluorescence spectroscopy, high‐performance liquid chromatography (HPLC), liquid chromatography/mass spectral techniques (LC‐MS), and total organic carbon (TOC) assays in order to identify the intermediates produced. Formation of oxygen species, such as H2O2 and O2.−, was also investigated to clarify the details of the reaction pathway. With the use of SiW12O404− ions as the photocatalyst, the photoreaction leads mainly to N‐dealkylation of the chromophore skeleton. In contrast, cleavage of the whole conjugated chromophore structure predominates in the presence of TiO2. Strong O2.−/HO2.− ESR signals were detected in the TiO2 dispersions, whereas only weak ESR signals for the O2.− radical ion were seen in the SiW12O404− solutions during the irradiation period. Experimental results imply that reduction of O2 occurs by different pathways in the two photocatalytic systems.

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Section: Interactions Between the Photocatalyst (Siw 12 O 40mentioning

confidence: 99%

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO₂ Dispersions under Visible‐Light Irradiation: Mechanistic Implications

Chen

Zhao

Lei

et al. 2004

Chemistry A European J

Self Cite

296

185

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“…For TiO 2 Degussa P25, zero point charge (z.p.c.) values of 6.8 [29] and 7.0 [30] have been reported. Consequently, at pH 2 and 4.5 titania particles are positively charged according to the following equilibrium:…”

Section: Influence Of Phmentioning

confidence: 94%

Mercury removal from aqueous solutions of HgCl2 by heterogeneous photocatalysis with TiO2

López-Muñoz

Aguado

Arencibia

et al. 2011

Applied Catalysis B: Environmental

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“…Methylene blue removal increases with treatment time because of the greater contact between fluid and photocatalyst. Finally, MB removal increases with pH because of the greater affinity between methylene blue, a cationic dye, and the TiO 2 surface, which is negatively charged at pH greater than the pH at the point of zero charge (pH pzc ), which is 6.8 for TiO 2 [22], as illustrated by the following equilibria [23] …”

Section: Reactor Optimizationmentioning

confidence: 99%

Design, Mass Transfer Studies, and Optimization of an Air-Sparged Tubular Photocatalytic Reactor for the Degradation of Methylene Blue

Dalida¹,

Ramoso²

2017

IJCEA

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Abstract-An alternative process for the removal of organic pollutants in aqueous systems is photocatalysis. The challenges hindering its industrial use are electron-hole recombination and mass transfer limitations. In order to address these problems, the objective of this study is to introduce air by sparging, and design an air-sparged photocatalytic reactor using titanium dioxide immobilized on borosilicate glass. The performance of the reactor on the removal of the model pollutant, methylene blue (MB), was evaluated and compared against the reactor operated without sparging. The effect of mass transfer limitations on reactor performance was also investigated by regression using a Langmuir-type model equation. Reactor performance was optimized using Response Surface Methodology to determine the set of initial MB concentration, treatment time, initial pH, and sparging rate that would result to the highest removal of methylene blue. The sparged photocatalytic reactor was able to degrade 57% MB in 2 hours, an improvement of 40% compared to no sparging. Mass transfer limitation studies showed that the reactor operates near the reaction-limited regime, and that the extent of mass transfer limitation effects was reduced. The set of parameters that maximizes methylene blue removal were 2.0 ppm MB, 120 minutes treatment time, pH 9.95 and 2.0 L/min sparging rate, with a predicted removal of 55.5%. Validation experiments resulted to 57.2% MB removal, and that the present reactor is comparable to similar reactors in literature, but with the advantage of using less expensive materials of construction and simpler immobilization technique.Index Terms-Photocatalysis, response surface methodology, tubular photocatalytic reactor, wastewater treatment.

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Photodegradation of surfactants. 11. .zeta.-Potential measurements in the photocatalytic oxidation of surfactants in aqueous titania dispersions

Cited by 129 publications

References 0 publications

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO₂ Dispersions under Visible‐Light Irradiation: Mechanistic Implications

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO₂ Dispersions under Visible‐Light Irradiation: Mechanistic Implications

Mercury removal from aqueous solutions of HgCl2 by heterogeneous photocatalysis with TiO2

Design, Mass Transfer Studies, and Optimization of an Air-Sparged Tubular Photocatalytic Reactor for the Degradation of Methylene Blue

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Photodegradation of surfactants. 11. .zeta.-Potential measurements in the photocatalytic oxidation of surfactants in aqueous titania dispersions

Cited by 129 publications

References 0 publications

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO2 Dispersions under Visible‐Light Irradiation: Mechanistic Implications

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO2 Dispersions under Visible‐Light Irradiation: Mechanistic Implications

Mercury removal from aqueous solutions of HgCl2 by heterogeneous photocatalysis with TiO2

Design, Mass Transfer Studies, and Optimization of an Air-Sparged Tubular Photocatalytic Reactor for the Degradation of Methylene Blue

Contact Info

Product

Resources

About

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO₂ Dispersions under Visible‐Light Irradiation: Mechanistic Implications

Photosensitized Degradation of Dyes in Polyoxometalate Solutions Versus TiO₂ Dispersions under Visible‐Light Irradiation: Mechanistic Implications