Use of palladium based catalysts in the hydrogenation of nitrates in drinking water: from powders to membranes

Strukul, Giorgio; Gavagnin, Roberta; Pinna, Francesco; Modaferri, Enza; Perathoner, Siglinda; Marella, M.; Tomaselli, M.

doi:10.1016/s0920-5861(99)00233-3

Cited by 141 publications

(63 citation statements)

References 19 publications

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“…A new technique that is actually under research is the catalytic reduction of nitrates to nitrogen, using hydrogen as reductant [2][3][4][5][6][7][8][9]. The catalysts used are based in a combination of a noble metal, such as Pd, Pt, Rh or Ir and a no noble metal, such as Cu, Sn, Ag or In [5][6][7][8][10][11][12][13][14]. The problem of this reaction is the formation of undesired subproducts such as nitrites or ammonia.…”

Section: Introductionmentioning

confidence: 99%

A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor

2011

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The aim of this work is to study the activity for the nitrate catalytic reduction in natural water, using a continuous stirred tank reactor, of Pd/Cu and Pd/Sn catalysts supported on different materials. The studied supports are: -Al 2 O 3 (commercial), active carbon, graphite, hydrotalcite and alumina synthesized in our laboratory with a high surface area. The activity and selectivity of the catalysts supported on these materials have been compared. The best results have been obtained with the Pd/Sn catalysts supported on alumina. These results show that the surface area of the support is not the only important characteristic for an active catalyst in this reaction, being also very significant its acid-base properties, its electrical conductivity and its interaction with the metallic active sites. The adequate combination of these characteristics is necessary to obtain an active catalyst. The influence of the Pd/Sn content on the activity of the alumina supported catalysts was studied, observing that the best activity was obtained when the Pd/Sn ratio was higher than 1. This result clearly indicates that it is necessary to have both Pd and Pd-Sn centers in order to obtain an active catalyst.

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Section: Introductionmentioning

confidence: 99%

A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor

2011

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“…In fact, the research interest on the use of these Pdbased thin films as catalysts is increasing. We reported in the past the use of these membranes for the catalytic selective reduction of nitrate in ground water [33]. Later, various authors have also investigated similar catalytic membranes for removing nitrates from groundwater [34,35].…”

Section: Introductionmentioning

confidence: 99%

The influence of the nanostructure on the effect of CO2 on the properties of Pd–Ag thin-film for H2 separation

Abate

Centi

et al. 2011

Applied Catalysis A: General

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Dedicated to the friend Helmut Knözinger on in the occasion of his 75 th birthday for the seminal contribution to the advancement of fundamental knowledge on catalysis. AbstractThe use of co-deposition instead of sequential deposition during the preparation of Pd-Ag thin films by electroless plating deposition leads to two different nanostructures, e.g. a dendritic nanostructure or a more compact and dense film, allowing to analyze the role of this parameter, at equal membrane composition, on the performances. In pure H2 the permeability to hydrogen of the second type of thin films is 3-4 times higher, but the presence of CO2 in the feed changes considerably the performances. The results are tentatively interpreted on the basis of a non-permanent in situ modification of the characteristics of the Pd-Ag thin films, with creation of strains and microholes particularly enhanced for the nanostructure present in the sample prepared by co-deposition. These strains and microholes are suggested to derive from the combined effect of CO2 (with creation of subsurface O and/or C) and of hydrogen diffusion through the thin film, which induces lattice expansion and stress on the nanograins. When the flux of H2 stops, there is a relatively rapid restoring of the initial situation. Scanning electron microscopy (SEM) characterization after the tests in the presence of CO2 indicates the presence of desintering consistently with above indications and the creation of crack like voids.

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“…Attempts to solve the contacting problem of the three phases and to reduce the diffusion resistance have included the use of novel catalyst supports [8,9].…”

Section: Introductionmentioning

confidence: 99%

Cloth catalysts for water denitrification

Matatov-Meytal

Barelko

Yuranov

et al. 2001

Applied Catalysis B: Environmental

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The use of glass fibers in the form of woven cloth (GFC), as a new type of catalytic support, was studied for the reduction of aqueous nitrate solutions using a Pd/Cu-GFC catalyst. The activity (per gram Pd) and selectivity to nitrogen were found to be comparable with those found for Pd-Cu catalysts supported on the other carriers. The maximal initial removal activity was found for a catalyst with a Pd/(Pd + Cu) ratio of 0.81. The corresponding activity was 0.7 mmol min −1 (g Pd ) −1 , and the selectivity was 97 mol% at 25 • C and pH 6.5 for initial nitrate concentration of 100 mg l −1 . The selectivity to nitrogen declined at high conversions of nitrate and high pH.

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Use of palladium based catalysts in the hydrogenation of nitrates in drinking water: from powders to membranes

Cited by 141 publications

References 19 publications

A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor

A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor

The influence of the nanostructure on the effect of CO2 on the properties of Pd–Ag thin-film for H2 separation

Cloth catalysts for water denitrification

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