Photocatalytic degradation of organic water contaminants: Mechanisms involving hydroxyl radical attack

Turchi, Craig; Ollis, David F.

doi:10.1016/0021-9517(90)90269-p

Cited by 1,980 publications

(958 citation statements)

References 51 publications

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“…The photo-generated electrons react with the molecular oxygen (O 2 ) to produce superoxide radical anions (ÁO À 2 ) and then photo-generated holes react with water to produce hydroxyl (ÁOH) radicals. These reactive radicals are then responsible for the degradation of organic compounds with QDs (Turchi and Ollis 1990;Pouretedal et al 2010). In this study, at the end of each interval time, the color difference in the irradiated dye solution of both pure and ZnO/starch QDs was observed and it confirms degradation of RhB dye, whereas no observable dye degradation in RhB dye solution was found after irradiation.…”

Section: Photocatalysis Analysismentioning

confidence: 50%

Structural and optical characterization of pure and starch-capped ZnO quantum dots and their photocatalytic activity

Vidhya¹,

Saravanan

Bhoopathi³

et al. 2014

Appl Nanosci

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Among the different types of metal oxides, zinc oxide (ZnO) is a most commonly used metal oxide in a broad variety of applications. In the present investigation, a modified green synthesis route was used to synthesize pure and starch-capped ZnO (ZnO/starch) quantum dots (QDs) and studied their structural and optical characteristics. In this study, hexagonal crystal structure was observed in both pure and ZnO/starch QDs using X-ray diffraction technique. A spherical-shaped surface morphology was found with the size of 5-10 nm using transmission electron microscope technique. The interaction between ZnO QDs and starch molecules was proved via Fourier infra-red spectrometer technique. On the other hand, their fluorescence behaviors were investigated using photoluminescence technique, in that the ZnO/starch QDs showed an enhanced emission behavior when compared to the pure ZnO QDs. Further, the solar photocatalytic activity of both the ZnO QDs was examined with the dye Rhodamine B (RhB) at the end of 30, 60, 90, and 120 min. In this, ZnO/ starch QDs show a good and more decomposition of RhB than pure ZnO QDs. Collectively, in the present study, green synthesis route produced an efficient QDs (pure and ZnO/starch) and it will be very useful for many other QDs. The ZnO/starch QDs are suitable for decomposing the RhB and other toxic organic dyes.

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Section: Photocatalysis Analysismentioning

confidence: 50%

Structural and optical characterization of pure and starch-capped ZnO quantum dots and their photocatalytic activity

Vidhya¹,

Saravanan

Bhoopathi³

et al. 2014

Appl Nanosci

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“…It is not a question that can be easily settled with steady-state kinetics experiments: every plausible kinetic model based on surfacebound or homogeneous reactive intermediates reacting with substrate yields kinetic information of the same form [58]. Thus, this is still a question of some dispute, though the more conventional position at this point is that most reactions occur at the surface [59].…”

Section: Isomerization Mechanisms and The Question Of Bulk Water Versmentioning

confidence: 99%

Mechanisms of catalyst action in the TiO2-mediated photocatalytic degradation and cis–trans isomerization of maleic and fumaric acid

Cubbage

et al. 2004

Applied Catalysis B: Environmental

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“…7 , by suitable electron scavengers, that must be present in the solution and available at the semiconductor interface. 6 On the other hand, in processes aiming at the oxidative destruction of a target organic substrate, any hole scavengers present in the same environment are potential competitors for the consumption of h + VB . 7,8 As far as electron scavenging is concerned, the most common electron scavenger, in aerated aqueous solution, is O 2 and its role has been emphasised, 1,7 including in the formation of "so-called selective oxygen species, which take part in the process of oxo functionalization of hydrocarbons".…”

Section: Introductionmentioning

confidence: 99%

Effect of scavengers on the photocatalytic digestion of organic matter in water samples assisted by TiO2 in suspension for the voltammetric determination of heavy metals

Cavicchioli

Gutz

2002

J. Braz. Chem. Soc.

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A influência de scavengers de elétrons e de lacunas positivas na digestão fotocatalítica de matéria orgânica na presença de partículas de TiO 2 em suspensão, foi investigada. O processo, que visa a determinação eletroquímica de traços de metais pesados em amostras de água, foi acompanhado mediante observação da recuperação da onda voltamétrica de Cd(II) em presença de EDTA, escolhido como ligante-modelo na simulação do efeito complexante da matéria orgânica natural. Confirmouse o poder acelerador de O 2 , que atua como removedor de elétrons. Na ausência de O 2 , função análoga é exercida pelo íon nitrato, mas não, ao menos aparentemente, pelo analito Cd(II). Já a adição de CH 3 OH apresenta efeito antagônico de scavenger de lacunas positivas, o que pode explicar porque a operação na presença de acetato (usado como tampão de pH), ao mesmo tempo em que proporciona um eficaz controle da acidez do meio, provoca uma certa redução do rendimento da fotodegradação.The influence of electron and hole scavengers in the photocatalytic digestion of organic matter in the presence of suspended particles of TiO 2 was investigated. The process, aiming at the electrochemical determination of traces of heavy metals in water samples, was followed through the recovery of the voltammetric wave of Cd(II) in the presence of EDTA, chosen as model ligand that mimics the complexing effect of natural dissolved organic matter. The accelerating power of O 2 , acting as electron scavenger, was confirmed. In the absence of O 2 , a similar function is played by nitrate ions but not, as it seems, by the analyte, Cd(II). On the other hand, CH 3 OH exhibits an antagonist effect as hole scavenger. This observation may explain why the acetate (from the pH buffer), used to control the medium acidity, leads to a certain reduction in the photocatalytic yield.

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Photocatalytic degradation of organic water contaminants: Mechanisms involving hydroxyl radical attack

Cited by 1,980 publications

References 51 publications

Structural and optical characterization of pure and starch-capped ZnO quantum dots and their photocatalytic activity

Structural and optical characterization of pure and starch-capped ZnO quantum dots and their photocatalytic activity

Mechanisms of catalyst action in the TiO2-mediated photocatalytic degradation and cis–trans isomerization of maleic and fumaric acid

Effect of scavengers on the photocatalytic digestion of organic matter in water samples assisted by TiO2 in suspension for the voltammetric determination of heavy metals

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