Ferrioxalate actinometry with online spectrophotometric detection

Lehóczki, Tímea; Józsa, Éva; Ősz, Katalin

doi:10.1016/j.jphotochem.2012.10.005

Cited by 48 publications

(36 citation statements)

References 15 publications

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“…This also means that the studied photoreactions followed zeroth order kinetics for longer time, thus their rates could be easily quantified. [53,54] The ratio of the rates of the accelerated photoreactions measured under the same conditions define the relative efficiency of different photocatalysts compared to each other. By this methodology we found that the rate of the photodegradation is 2.3 mAU/min with A13 and 5.4 mAU/min with the same mass-concentration of anatase, as seen in Fig.…”

Section: Experiments In the Custom Built Photoreactorthe Results Of mentioning

confidence: 99%

“…This kinetic curve cannot be simulated by taking into account only the depletion of SA in unhindered parallel photoreactions, i.e. using the widely accepted kinetic approximations (Langmuir-Hinshelwood model) [25,33,43] for the catalyzed process, and the photochemical model [53,54,57] for the uncatalyzed process. In other words, the amount of SA consumed and the drop of reaction rate cannot be described by two parallel pseudo-first-order photoreactions.…”

Section: µMol Mb Is Adsorbed By 574 Mg A13 Aerogel Which Is a Consimentioning

confidence: 99%

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Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Lázár

Kalmár

Peter

et al. 2015

Applied Surface Science

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Abstract. Titania-silica composite aerogels with 16 -29% Ti-content by the mass were synthesized by the sol-gel method from different Ti-precursors, and calcined at 500°C. These aerogels are highly amorphous as no crystalline TiO 2 phase can be detected in them by X-ray diffraction methods, and show the dominating presence of either mesopores or macropores.The incorporation of Ti into the silica structure is shown by the appearance of characteristic IR transitions of Si-O-Ti vibrations.The characteristic band-gap energies ofthe different aerogelsare estimated to be between 3.6 and 3.9 eV from UV reflection spectra. Band-gap energy decreases with decreasing pore-size. When suspended in solution,even these highly amorphous aerogels accelerate the photodegradation of salicylic acid and methylene blue compared to simple photolysis. Kinetic experiments were conducted under illumination, and also in the dark to study the adsorption of the substrates onto the suspended aerogels.We assume that the fast in-situadsorption of the organic substratesmask the suspended aerogel particles from UV photons,which reduces the rate of photocatalysis. We managed to mathematically separate the parallelprocesses of photocatalysis and adsorption, and develop a simple kinetic model to describe the reaction system.

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Section: Experiments In the Custom Built Photoreactorthe Results Of mentioning

confidence: 99%

Section: µMol Mb Is Adsorbed By 574 Mg A13 Aerogel Which Is a Consimentioning

confidence: 99%

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Lázár

Kalmár

Peter

et al. 2015

Applied Surface Science

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“…The ˚ value for the [Ru(bpy) 2 (dmbpy)] 2+ → [Ru(bpy) 2 (H 2 O) 2 ] 2+ photoreaction has been determined using the ferrioxalate actinometry method [30,31]. Briefly, the actinometer and [Ru(bpy) 2 (dmbpy)] 2+ samples were illuminated at 532 nm over several 5 min time intervals.…”

Section: Quantum Yieldsmentioning

confidence: 99%

Photoacoustic calorimetry study of ligand photorelease from the Ru(II)bis(2,2′-bipyridine)(6,6′-dimethyl-2,2′-bipyridine) complex in aqueous solution

Word

Whittington

Karolak

et al. 2015

Chemical Physics Letters

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“…42 The photon flux of this lamp is 2.7×10 17 s −1 in the geometric arrangement used in our experiments. 43 Photoreactions of these samples result in the formation of colored hydroxyquinones and colorless hydroquinones, the mixture of which seems to be stable for several days even under normal laboratory light conditions. 44 The formation reaction was followed using a pH-stat titrating system (ABU 91 AUTOBURETTA RADIOMETER COPENHAGER) and was completed for all substituted derivatives after a maximum illumination time of 1 hour.…”

Section: Spectrophotometric Determination Of Pk a Valuesmentioning

confidence: 99%

Kinetic studies of hydroxyquinone formation from water soluble benzoquinones

et al. 2014

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Table of contents entryThe kinetics of the reactions between 1,4-benzoquinones and hydrogen peroxide were studied.A systematic study of substituent effects revealed a Hammett-like correlation, where the rate of reaction is mainly determined by electronic effects. 3 AbstractThe kinetics and mechanisms of the redox reactions between hydrogen peroxide and 1,4-benzoquinone, 2-methyl-1,4-benzoquinone, 2,6-dimethyl-1,4-benzoquinone, 2-chloro-1,4-benzoquinone and 2,6-dichloro-1,4-benzoquinone were studied in aqueous media using spectrophotometric monitoring. The formation and decay of a hydroxylated 1,4-benzoquinone was detected. The formation of the intermediate was first order with respect to the parent 1,4-bezoquinone and hydrogen peroxide, whereas inverse first order dependence was revealed with respect to hydrogen ion. The decomposition reaction had two parallel pathways: one was first order with respect to the intermediate, while the other showed second-order dependence.The values of the rate constant measured for the formation step were successfully correlated with both the redox potentials of the substituted quinone/hydroquinone systems and the pK a values of the hydroxylated quinone derivatives. Therefore, electronic effects govern the reactivity of the quinones in this process. NMR and GC-MS measurements were carried out to identify the products in the system. Quantum mechanical calculations were also carried out in these systems.4

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Ferrioxalate actinometry with online spectrophotometric detection

Cited by 48 publications

References 15 publications

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Photoacoustic calorimetry study of ligand photorelease from the Ru(II)bis(2,2′-bipyridine)(6,6′-dimethyl-2,2′-bipyridine) complex in aqueous solution

Kinetic studies of hydroxyquinone formation from water soluble benzoquinones

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