Photocatalytic oxidative Degradation of vapors of some organic compounds over TiO2

Lichtin, Norman N.; Avudaithai, M.; Berman, E.; Dong, Junchang

doi:10.1163/156856794x00531

Cited by 34 publications

(26 citation statements)

References 15 publications

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“…The photosensitizing effect recently observed in mixtures of TCE with other organic pollutants also supports a mechanism involving Cl radicals. 24,26,27 However, a reaction pathway proposed by Nimlos et al 22 which associates the direct attack of Cl radical on the TCE double bond still needs to be proved. While a Cl radical chain reaction mechanism can explain the formation of DCAC and phosgene, in early studies 8-10 the complete mineralization of TCE was never observed nor were the yields of CO 2 production very high even after long UV irradiation times.…”

Section: Tcementioning

confidence: 99%

In Situ Solid-State NMR Studies of Trichloroethylene Photocatalysis: Formation and Characterization of Surface-Bound Intermediates

1998

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In situ solid-state NMR methodologies have been employed to investigate the photocatalytic oxidation of trichloroethylene (TCE) over two TiO2-based catalysts, Degussa P-25 powder and a monolayer TiO2 catalyst dispersed on porous Vycor glass. 13C magic angle spinning (MAS) experiments reveal that similar reaction intermediates form on the surfaces of both catalysts. Long-lived intermediates, including dichloroacetyl chloride (Cl2HCCOCl, DCAC), carbon monoxide, and pentachloroethane and final products CO2, phosgene (Cl2CO), and HCl were observed under dry conditions. The presence of molecular oxygen was found to be essential for TCE photooxidation to proceed. Adsorbed water was found to greatly reduce the formation of phosgene. The formation of surface-bound dichloroacetate and trichloroacetate species was observed and identified via 13C cross polarization MAS experiments. Dichloroacetate, which forms from mobile DCAC, appears to be bound to the nonirradiated surfaces of the powdered TiO2 catalyst and further degradation was not possible. Formation of di- and trichloroacetate also takes place on the TiO2/PVG catalyst in the absence of light; however, their concentrations are low. Degradation studies of these surface-bound species indicate that the photooxidation of dichloroacetate is slow and results in the formation of phosgene and CO2, while trichloroacetate remains resistive to degradation on the TiO2/PVG catalyst. Our results also indicate that the formation of DCAC and phosgene seems to be a general result of TCE degradation which is not limited to TiO2 photocatalysis but instead may be more characteristic of the types of initiating species which are formed by UV irradiation. However, the TiO2 surface is the most effective in terms of the observed initial rates of degradation.

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Section: Tcementioning

confidence: 99%

In Situ Solid-State NMR Studies of Trichloroethylene Photocatalysis: Formation and Characterization of Surface-Bound Intermediates

1998

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“…It is probative for the evidence of increase of the band of C-O at 1200 cm −1 , reported by other group for Pt-TiO 2 photocatalyst [42,43].…”

Section: Mechanism Of Photocatalytic Degradation Of Methanol On Pt-znmentioning

confidence: 58%

Facing-target sputtering deposition of ZnO films with Pt ultra-thin layers for gas-phase photocatalytic application

Zhang

Hossain

Arakawa

et al. 2010

Journal of Hazardous Materials

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“…This type of isotherm originates from the cooperative isothermal adsorption, i.e. the adsorbed molecules promote higher adsorption of other molecules and tend to be adsorbed in groups [44]. We note also that the activated bentonite adsorbs much better than the natural bentonite.…”

Section: Adsorption Isothermsmentioning

confidence: 67%

Removal of Chlorothalonil from water by a bentonite treated chemically

Boudouara¹,

Marouf²,

Ouadjenia³

et al. 2017

JMES

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The adsorption of Chlorothalonil fungicide from aqueous solution onto raw and activated bentonite samples was investigated as a function of parameters such as pH, contact time, and temperature. The acid activation of natural bentonite was performed by treatment with hydrochloric solution of different concentrations. The high adsorption capacity of chlorothalonil was obtained by activated bentonite at 323 K in the range of pH 3-4 for 60 min of contact time. It was be 32.01 and 42.88 mg/g for raw and bentonite activated by 1N hydrochloric acid, respectively. The Langmuir and Freundlich adsorption models were applied to describe the related isotherms. Freundlich equation has shown the best fitting with the experimental data. The pseudo-first order and pseudo-second order kinetic models were used to describe the kinetic data. The changes of enthalpy, entropy and Gibbs free energy of adsorption process were determined. The results indicated that the adsorption of chlorothalonil occurs spontaneously as an endothermic process.

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Photocatalytic oxidative Degradation of vapors of some organic compounds over TiO2

Cited by 34 publications

References 15 publications

In Situ Solid-State NMR Studies of Trichloroethylene Photocatalysis: Formation and Characterization of Surface-Bound Intermediates

In Situ Solid-State NMR Studies of Trichloroethylene Photocatalysis: Formation and Characterization of Surface-Bound Intermediates

Facing-target sputtering deposition of ZnO films with Pt ultra-thin layers for gas-phase photocatalytic application

Removal of Chlorothalonil from water by a bentonite treated chemically

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