The influence of impurities contained in quartz sand on the catalytic reduction of nitric oxide by carbon monoxide

Schoderböck, Peter; Lahaye, J.

doi:10.1016/0169-4332(95)00327-4

Cited by 11 publications

(16 citation statements)

References 16 publications

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“…The sodium ions in this second phase will not lead to the formation of O - species and will have different catalytic properties toward the investigated reactions. This is suggested to be observed in Figure for Na + Fe concentrations exceeding about 0.3 wt % and is in line with the discussion put forward by Schoderböck and Lahaye for Fe impurities in quartz sand …”

Section: Discussionsupporting

confidence: 91%

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Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H₂

Acke

Panas

1998

J. Phys. Chem. B

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The heterogeneous reduction of NO by H2 and CO over different CaO materials is investigated. The dependence of the specific NO reduction rate on the impurity content is demonstrated for both reducing species. The roles of two specific impurities, i.e., Na and Fe, as well as their combined effect are investigated. The apparent activation energies for the NO + CO and NO + H2 reactions are determined for three different calcium oxides. Values between 26 and 28 kcal/mol are obtained. The influence of impurity content is found in the preexponential factor of the Arrhenius equation. A reaction mechanism based on a rate-determining surface-oxygen-abstraction step is suggested. This mechanistic understanding is explored to compare the activities of other alkaline-earth oxides. Particularly, a linear correlation between the apparent activation energy and the lattice parameter is observed.

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Section: Discussionsupporting

confidence: 91%

“…An initial increase of the specific activity was observed with Li doping. The importance of the impurity level as well as the chemical surrounding of the impurity has been discussed for iron in quartz . It was shown that Fe as an impurity is not catalytically active when iron is incorporated in a well-defined crystal structure (illite).…”

Section: Introductionmentioning

confidence: 99%

Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H₂

Acke

Panas

1998

J. Phys. Chem. B

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“…Clearly the crudeness of the data analysis does not permit drawing strong conclusions concerning the true kinetics of (R3). It should be noted that reported activation energies for (R3) have been quite varied, ranging from 75 to 176 kJ/mol on limestone, 23 kJ/mol on quartz, 174 kJ/mol on coal char, 64 to 108 kJ/mol on quartz and sand surfaces …”

Section: Resultsmentioning

confidence: 99%

“…There have been many reports concerning the catalysis of (R3) by various types of surfaces, including quartz, , impure quartz sands, calcined limestone and dolomite, − sulfided limestone, transition-metal oxides, other mixed catalysts, , carbon-supported transition metals, , and carbon-supported alkali . It has also been reported that coal ash has low catalytic activity and CFBC bed ash can have high activity .…”

Section: Introductionmentioning

confidence: 99%

The Role of Carbon Monoxide in the NO−Carbon Reaction

1999

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The enhancement of the NO/carbon reduction reactions by carbon monoxide has been demonstrated for carbons of widely varying nature (coal char, phenolic resin-derived char and graphite). The evidence supports enhancement of NO reduction via a carbon-surface-catalyzed reaction such as NO + CO → 1/2N2 + CO2. This reaction appears to be characterized by an activation energy of around 116 kJ/mol, and by zero order with respect to CO, in the range of CO pressures examined here (up to order 500 ppm). This suggests that an oxide stripping reaction, e.g., CO + C(O) → CO2 + C*, cannot be invoked in its usual form, to explain the rate enhancement. The reaction appears to be first order with respect to NO, at high temperatures and at NO concentrations of above roughly 100 ppm, but kinetic analysis is complicated by the fact that the NO−carbon reaction itself does not have a unique order at low temperatures. It is also shown that kinetic analysis can be greatly complicated in the presence of other oxidizing gases or surface oxides deposited by these gases.

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“…The study of the soot-NO reaction in the presence of CO was performed at 1373 K. Depending on the conditions of temperature and CO concentration, quartz has been reported to present catalytic activity in the reduction of nitric oxide by carbon monoxide, following the same scheme showed in reaction (7) [26][27][28]. Therefore, a previous test was performed to check whether the quartz wool, silica sand particles and the quartz reactor used in this work were inert under the reaction conditions employed.…”

Section: Methodsmentioning

confidence: 99%

Acetylene soot reaction with NO in the presence of CO

Mendiara

Alzueta

Millera

et al. 2009

Journal of Hazardous Materials

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The influence of impurities contained in quartz sand on the catalytic reduction of nitric oxide by carbon monoxide

Cited by 11 publications

References 16 publications

Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H₂

Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H₂

The Role of Carbon Monoxide in the NO−Carbon Reaction

Acetylene soot reaction with NO in the presence of CO

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The influence of impurities contained in quartz sand on the catalytic reduction of nitric oxide by carbon monoxide

Cited by 11 publications

References 16 publications

Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H2

Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H2

The Role of Carbon Monoxide in the NO−Carbon Reaction

Acetylene soot reaction with NO in the presence of CO

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Product

Resources

About

Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H₂

Promoting Effects of Na and Fe Impurities on the Catalytic Activity of CaO in the Reduction of NO by CO and H₂