Radial-Flow Reactor Packed with a Catalytic Cloth:  Nitrate Reduction in Hydrogen-Saturated Water

Matatov-Meytal, Uri

doi:10.1021/ie050260v

Cited by 11 publications

(8 citation statements)

References 16 publications

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“…Moreover, alloying of metals may result in important changes in their activity and selectivity . The selection of the support is also important for this process, since it was shown that the support affects the catalyst activity and selectivity. ,− …”

Section: Introductionmentioning

confidence: 99%

Pd−Cu and Pt−Cu Catalysts Supported on Carbon Nanotubes for Nitrate Reduction in Water

Soares

Órfão

Pereira

2010

Ind. Eng. Chem. Res.

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The influence of the preparation conditions on the performance of Pd-Cu and Pt-Cu supported on multiwalled carbon nanotubes for the reduction of nitrates was studied and compared with that obtained using a commercial activated carbon as support. Different preparation conditions lead to different catalytic activities and selectivities. Generally, the activity decreases by increasing the calcination and reduction temperatures for the catalysts supported on the original carbon nanotubes, where the nitrate conversion varies from 67% (noncalcined and nonreduced) to 15% (calcined and reduced at 200 °C) for the pair Pd-Cu after 5 h of reaction; the inverse performance was observed for the catalysts supported on carbon nanotubes previously oxidized with HNO 3 and on this same sample heat treated at 400 °C. The functional groups created during the oxidation treatment have a negative effect on the catalyst performance. For all the preparation conditions tested, the Pd-Cu pair is more selective to nitrogen than the pair Pt-Cu; 82% and 37% are the highest values obtained for each pair, respectively. Carbon nanotubes are demonstrated to be a good support for this reaction.

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Section: Introductionmentioning

confidence: 99%

Pd−Cu and Pt−Cu Catalysts Supported on Carbon Nanotubes for Nitrate Reduction in Water

Soares

Órfão

Pereira

2010

Ind. Eng. Chem. Res.

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“…However, nitrate in the groundwater of some regions is as high as 50 mgN/L. Biological and physicochemical treatment has been developed to deal with excess nitrate, but catalytic denitridation as an emerging technology has attracted intensive attention because of its more economical and ecological merits – .…”

Section: Introductionmentioning

confidence: 99%

“…Biological and physicochemical treatment has been developed to deal with excess nitrate, but catalytic denitridation as an emerging technology has attracted intensive attention because of its more economical and ecological merits. [1][2][3] Since 1989, when a Pd-Cu bimetal catalyst was found to be active by Tacke and Vorlop, 4,5 the activity and selectivity of nitrate hydrogenation on Pd-Cu bimetallic catalysts have been extensively discussed and found to be related to the structure of active components and the properties of supports. Various supports such as Al 2 O 3 , 6,7,11,14,17 clay, 9 active carbon, 18,19,22,23,26 beta-zeolite, 20,21 ZrO 2 , 10 SnO 2 , 15 Pumice, 11 glass fiber, 12 resins, 13,25 hydrotalcite, 8,16 TiO 2 , 27 and mordenite 24 have been examined.…”

Section: Introductionmentioning

confidence: 99%

Size-Dependent Hydrogenation Selectivity of Nitrate on Pd−Cu/TiO₂ Catalysts

et al. 2008

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Catalytic hydrogenation of nitrate (NO3 −) in water on Pd−Cu ensembles has been denoted as a promising denitridation method, but its hydrogenation selectivity remains challenging. In this study, the hydrogenation selectivity of nitrate on the Pd−Cu/TiO2 systems was discussed mainly concerning the size effect of Pd−Cu ensembles in a gas−liquid cocurrent flow system. Demonstrated by their TEM images, homogeneous morphologies as well as narrow size distributions of Pd−Cu ensembles on titania have been prepared by a facile photodeposition process, and the size of the ensembles was controlled and varied with the total metal loadings. The different XRD patterns and XPS spectra of Pd−Cu/TiO2 catalysts from their corresponding monometallic counterparts suggested the formation of Pd−Cu complex on the surface of TiO2. It is first indicated that the hydrogenation selectivity of nitrate generally depends on the size of active phase with critical size of approximately 3.5 nm, below which NO2 − becomes the predominant product instead of nitrogen. Ammonium production was increasing slowly throughout the reaction, but this can be efficiently restrained by bubbling CO2. The optimal catalytic activity and nitrogen selectivity of 99.9% and 98.3% respectively could be achieved on the Pd−Cu/TiO2 catalyst with average size of 4.22 nm under the modification of CO2 after approximately 30 min reduction. The catalytic activities of nitrite on several Pd−Cu bimetallic catalysts were examined to strongly depend on the size of active metal, as is well responsible for the observed distinct hydrogenation selectivity of nitrate.

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“…Other important aspects fundamental to NO 3 RR, such as the reactor design, membrane development, optimal operating conditions, etc. , are beyond the scope of this review and can be found elsewhere. − Finally, the challenges and future perspectives in this field are provided, aiming to stimulate more insights and invoke new design strategies for future catalyst development.…”

Section: Introductionmentioning

confidence: 99%

Powering the Remediation of the Nitrogen Cycle: Progress and Perspectives of Electrochemical Nitrate Reduction

Min

Gao

Yan

et al. 2021

Ind. Eng. Chem. Res.

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Nitrate pollution in surface and ground waters has become a potent threat to ecosystem and human health. Electrochemical nitrate reduction is a promising strategy to directly convert excessive nitrates in water into environmentally benign dinitrogen gas or value-added chemicals such as ammonia under mild conditions. Once coupled with renewable electricity, it represents an eco-friendly and energy-efficient route for the recirculation of nitrogen species into the nitrogen cycle and economy. Understanding fundamental mechanisms of nitrate reduction is therefore crucial to design and develop high-performing electrocatalysts. In this review, we first discuss recent discoveries of reaction mechanisms for electrochemical nitrate reduction, focusing on the various pathways to desirable products (nitrogen and ammonia). The direct electron transfer and atom hydrogen transfer pathways are discussed in detail. We then summarize and discuss recent advances in catalytic materials spanning the material space from precious metal, nonprecious metal, and nonmetal catalysts. The existing challenges of electrochemical nitrate reduction are also highlighted. Finally, we provide the perspectives of the opportunities and outlook for the future development in electrochemical nitrate reduction.

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Radial-Flow Reactor Packed with a Catalytic Cloth: Nitrate Reduction in Hydrogen-Saturated Water

Cited by 11 publications

References 16 publications

Pd−Cu and Pt−Cu Catalysts Supported on Carbon Nanotubes for Nitrate Reduction in Water

Pd−Cu and Pt−Cu Catalysts Supported on Carbon Nanotubes for Nitrate Reduction in Water

Size-Dependent Hydrogenation Selectivity of Nitrate on Pd−Cu/TiO₂ Catalysts

Powering the Remediation of the Nitrogen Cycle: Progress and Perspectives of Electrochemical Nitrate Reduction

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Radial-Flow Reactor Packed with a Catalytic Cloth: Nitrate Reduction in Hydrogen-Saturated Water

Cited by 11 publications

References 16 publications

Pd−Cu and Pt−Cu Catalysts Supported on Carbon Nanotubes for Nitrate Reduction in Water

Pd−Cu and Pt−Cu Catalysts Supported on Carbon Nanotubes for Nitrate Reduction in Water

Size-Dependent Hydrogenation Selectivity of Nitrate on Pd−Cu/TiO2 Catalysts

Powering the Remediation of the Nitrogen Cycle: Progress and Perspectives of Electrochemical Nitrate Reduction

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Size-Dependent Hydrogenation Selectivity of Nitrate on Pd−Cu/TiO₂ Catalysts