Photocatalytic degradation of 4-nitrophenol in aqueous TiO2 suspensions: Theoretical prediction of the intermediates

San, Nevim; Hatipoğlu, Arzu; Koçtürk, Gülin; Çınar, Zekiye

doi:10.1016/s1010-6030(01)00620-7

Cited by 234 publications

(111 citation statements)

References 27 publications

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“…Since the formation of highly toxic reaction intermediates is possible, identification of the degradation products is essential. Furthermore, the elucidation of the mechanism of the photocatalysis might be useful for the prediction of degradation of other substrates using the same catalyst [24]. Since photocatalytic degradation has been suggested to be similar to biological processes, insights might be obtained from these studies regarding metabolic transformation of diazinon in living organisms [25].…”

Section: Iazinon [Oo-diethyl O-(2-mentioning

confidence: 99%

Identification of photocatalytic degradation products of diazinon in TiO₂aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Kouloumbos¹,

Tsipi²,

Hiskia

et al. 2003

J. Am. Soc. Mass Spectrom.

131

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The photocatalytic degradation of the organophosphorus insecticide diazinon in aqueous suspensions has been studied by using titanium dioxide as a photocatalyst. The degradation of the insecticide was a fast process and included the formation of several intermediates that were identified using GC/ion-trap mass spectrometry with EI or CI in positive and negative ionization mode and HPLC/electrospray-QqTOF mass spectrometry. Since primarily hydroxy derivatives were identified in these aqueous suspensions, the mechanism of degradation was probably based on hydroxyl radical attack. The initial oxidative pathways of the degradation of diazinon involved the substitution of sulfur by oxygen on the P¢S bond, cleavage of the pyrimidine ester bond, and oxidation of the isopropyl group. Exact mass measurements of the derivatives allowed the elemental formula of the molecules to be determined confidently. Similarities to the metabolic pathways occurring in living organisms were observed. (J Am Soc Mass Spectrom 2003, 14, 803-817)

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Section: Iazinon [Oo-diethyl O-(2-mentioning

confidence: 99%

Identification of photocatalytic degradation products of diazinon in TiO₂aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Kouloumbos¹,

Tsipi²,

Hiskia

et al. 2003

J. Am. Soc. Mass Spectrom.

131

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“…photosensitization) resulting in enhanced photocatalytic activity is one of the most important aspects of heterogeneous photocatalysis. Deposition of different metals (like Pt, Pd, Au, Ag, Fe, Nb and Cu) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] or oxides such as WO 3 [17] onto titanium dioxide has been widely used as a technique to extend the light absorption to the visible region.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic activity of silver-modified titanium dioxide at solid–liquid and solid–gas interfaces

Kőrösi

Papp

Ménesi

et al. 2008

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Silver-modified titania samples (Ag-TiO 2 ) with varying silver content (0.1-1.0 wt%) were prepared. Silver-modification of titanium dioxide was examined by TEM, XRD, XPS and DR-UV-vis spectroscopy. Ag or AgO x particles on TiO 2 surface could not be observed by XRD and TEM investigation, however the color of the Ag-TiO 2 samples varied between light rose and purple-brown. XPS measurements revealed that silver exists mainly in oxide form. The photocatalytic activity of pure and Ag-TiO 2 samples were compared both in solid-liquid and in solid-gas interfaces. In the liquid phase the 2,2 -thiodiethanol was used as test molecule. Ethanol photodegradation was examined in gas phase at dry initial condition. It was shown that the rate of photooxidation of organic compounds significantly enhanced by silver-modification of titania.

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“…It can be seen from Figure 3 that degree of decolorization of dye increased with increasing amount of photocatalyst TiO 2 , reaching highest value at catalyst loading 1.0 g/l and then decreased. This behavior was caused by the so called shielding effect at higher concentration of catalyst where the suspended TiO 2 reduces the penetration of light in solution [20]. Even though more catalyst surface was available for dye adsorption, certain part of the catalyst was not exposed to photons as interfacial area between the reaction solution and the photocatalyst got reduced.…”

Section: Effect Of Catalyst Dosementioning

confidence: 99%

Photocatalytic decolorization of reactive black 5 dye in aqueous TiO₂/ZnO suspension under UV light

Kapoor

Kanwar

2008

WIT Transactions on Ecology and the Environment

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The release of colored wastewaters in the ecosystem is a dramatic source of aesthetic pollution, eutrophication, and perturbations in aquatic life. Research devoted to the ill-effects caused by chemicals have acquired importance as a result of the increased care and attention paid to the environment and human health by international, socio-political, and legislative authorities. Compliance with strict quality standards is especially called for, in the case of handling and using toxic substances that affect the environment and health. Growing concern about environmental issues has prompted the industries to investigate appropriate and eco-friendly treatment technologies. The prime need of these industries is to have a simple but effective inexpensive technology for the treatment of wastewater. Photocatalysis is considered as an important part of emerging greener technology as it uses environmentally friendly oxidants (oxygen, hydrogen peroxide or ozone), photocatalysts (titanium dioxide, ferrous ions or its complexes), and ultraviolet (UV) radiation to degrade and mineralize the toxic organic pollutants. In this study, the photodecolorization of Reactive Black 5 dye has been performed using titanium dioxide (TiO 2 P-25 Degussa) and zinc oxide (ZnO) using a mixed batch reactor. The rate of degradation was studied in terms of changes in absorption spectra and reduction in chemical oxygen demand (COD). Various process parameters such as catalyst dose, pH, and dye initial concentration have been varied and their effect on the decolorization efficiency has been studied. The photocatalyst zinc oxide was found to be more efficient as compared with titanium dioxide.

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Photocatalytic degradation of 4-nitrophenol in aqueous TiO2 suspensions: Theoretical prediction of the intermediates

Cited by 234 publications

References 27 publications

Identification of photocatalytic degradation products of diazinon in TiO₂aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Identification of photocatalytic degradation products of diazinon in TiO₂aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Photocatalytic activity of silver-modified titanium dioxide at solid–liquid and solid–gas interfaces

Photocatalytic decolorization of reactive black 5 dye in aqueous TiO₂/ZnO suspension under UV light

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Photocatalytic degradation of 4-nitrophenol in aqueous TiO2 suspensions: Theoretical prediction of the intermediates

Cited by 234 publications

References 27 publications

Identification of photocatalytic degradation products of diazinon in TiO2aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Identification of photocatalytic degradation products of diazinon in TiO2aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Photocatalytic activity of silver-modified titanium dioxide at solid–liquid and solid–gas interfaces

Photocatalytic decolorization of reactive black 5 dye in aqueous TiO2/ZnO suspension under UV light

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Identification of photocatalytic degradation products of diazinon in TiO₂aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Identification of photocatalytic degradation products of diazinon in TiO₂aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

Photocatalytic decolorization of reactive black 5 dye in aqueous TiO₂/ZnO suspension under UV light