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Rutten, O. W. J. S.; Sandwijk, A. van; Weert, G. Van

doi:10.1023/a:1003412613806

Cited by 47 publications

(32 citation statements)

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“…The body of the electrochemical cell was made of DURAN (Bank Elektronik, Inc., Germany) heat-resistant laboratory glass. The volume of the working electrode compartment was 1 liter, whereas the volume of the counter electrode compartment was 500 cm 3 . A fritted glass disk separated the working electrode chamber from the counter electrode chamber.…”

Section: Methodsmentioning

confidence: 99%

“…Several of the reported investigations were carried out in either acidic or alkaline concentrated nitrate and nitrite ion solutions for environmental reasons [3,5,6]. Lu et al [2] used different hydrogen storage cathodes to reduce nitrate to ammonia in alkaline media and found that the efficiency of ammonia production depended on the nitrate ion concentration, electrode type and applied current density.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic Studies of the Electrochemical Treatment of Nitrate and Nitrite Ions on Iridium‐Modified Carbon Fiber Electrodes

Kalu²,

Tarján

et al. 2004

Chem Eng & Technol

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Electrochemical reductions of nitrate and nitrite ions in neutral solution were studied using an Ir-deposited carbon fiber electrode. The objective of the study was to set up a process to remove nitrate and nitrite ions from industrial and municipal wastes as well as from the nitrate and nitrite ion enriched water supplies. Since nitrate and nitrite ion reduction kinetics is very slow on plain carbon, the iridium-modified fibers showed a significant reduction of nitrate and nitrite ions. Nitrogen and ammonia were identified as the two major gaseous products of the reduction process. A first-order inhibition kinetics model is proposed and was used to analyze the nitrate and nitrite ion reduction kinetics. The reduction rates of nitrate and nitrite ions were favored at higher cathode potential (cf. ±950 mV and ±850 mV) in a solution of pH = 7.0 with hydrogen evolution efficiency increasing with cathodic potential. A simple model for the batch re-circulation process was developed for the reduction of nitrate ion at surface-modified fiber electrode. There was a good agreement between the model predictions and experimental results.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetic Studies of the Electrochemical Treatment of Nitrate and Nitrite Ions on Iridium‐Modified Carbon Fiber Electrodes

Kalu²,

Tarján

et al. 2004

Chem Eng & Technol

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“…[27] v y = -0.51ω 3/2 v -1/2 y 2 (20) in which ν is the kinematic viscosity of the liquid (cm 2 s -1 ). Integration of Equation (19) leads to Equation (21).…”

Section: Reduction Mechanism and Kinetic Modellingmentioning

confidence: 99%

Mechanism of Nitric Acid Reduction and Kinetic Modelling

2014

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International audienceIn France, the recycling of nuclear waste fuels involves theuse of hot concentrated nitric acid. The understanding andprediction of the behaviour of the structural materials(mainly austenitic stainless steels) requires the determinationand modelling of the nitric acid reduction process. Nitric acidis indirectly reduced by an autocatalytic mechanism dependingon the cathodic overpotential and acid concentration.This mechanism has been widely studied. All theauthors agree on its autocatalytic nature, characterized bythe predominant role of the reduction products. It is also generallyadmitted that neither nitric acid nor the nitrate ion isthe electroactive species. However, the nature of the electroactivespecies, the place where the catalytic species regeneratesand the thermodynamic and kinetic behaviour ofthe reaction intermediates remain uncertain. The aim of thisstudy was to clarify some of these uncertainties by performingan electrochemical investigation of the reduction of4 M nitric acid at 40 °C at an inert electrode (platinum orgold). An inert electrode was chosen as the working electrodein a first step to avoid its oxidation and focus the research on the reduction mechanism. This experimental workenabled us to suggest a coherent sequence of electrochemicaland chemical reactions. Kinetic modelling of this sequencewas then carried out for a gold rotating disk electrode.A thermodynamic study at 25 °C allowed the compositionof the liquid and gaseous phases of nitric acid solutionsin the concentration range 0.5–22 M to be evaluated. The kineticsof the reduction of 4 M nitric acid was investigated bycyclic voltammetry and chronoamperometry at an inert electrodeat 40 °C. The coupling of chronoamperometry and FTIRspectroscopy in the gaseous phase led to the identification ofthe gaseous reduction products as a function of the cathodicoverpotential. The results showed that the reduction processis autocatalytic for potentials between 0.6 and 1.15 V/NHE.The electroactive species may be regenerated at the surfaceof the electrode for lower potentials, otherwise this regenerationprocess occurs in solution by a homogeneous chemicalreaction. When the potential is less than 0.6 V/NHE, the fastreduction of nitrogen oxide may lead to rupture of the autocatalyticcycle

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“…Electrocatalytic processes have been extensively studied in the last 30 years [15][16][17][18][19][20][21]. Three different ways of electrocatalytic reduction of nitrates are known [5]: (i) addition of electrocatalytically active ions such as VO 3 ) , MoO 4 2) , WO 4 2) or cobalt complexes [22] directly to the treated solution (ii) immobilization of the catalyst on the cathode surface, for example, carbon electrode modified with phthalocyanine complexes [23] and (iii) electrocatalytic reduction on solid electrodes [15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…Three different ways of electrocatalytic reduction of nitrates are known [5]: (i) addition of electrocatalytically active ions such as VO 3 ) , MoO 4 2) , WO 4 2) or cobalt complexes [22] directly to the treated solution (ii) immobilization of the catalyst on the cathode surface, for example, carbon electrode modified with phthalocyanine complexes [23] and (iii) electrocatalytic reduction on solid electrodes [15][16][17][18][19][20][21]. Many solid electrodes have been tested including Pb [18,19,24], Ni [18,19,24,25], Fe [19,24], Cu [15,23,25,26], Pt [16,27,28], Zn [29], Ru [30], Pd [26,30,31], C [21,24,25] and Ir [16,30]. Among these, copper was shown to be the most efficient electrocatalyst [32] concerning the rate of the nitrate reduction.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical reduction of nitrate ion on various cathodes ? reaction kinetics on bronze cathode

2005

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The electrochemical reduction of NO 3 ) in 0.1 M K 2 SO 4 and 0.05 M KNO 3 solution was studied on various electrodes in two different cell configurations, a divided and an undivided one. The products in all cases were NO 2 ) , NH 3 , N 2 and small amounts of NO 2 and NO. The more efficient cathodes as regards the conversion of NO 3 ) to N 2 were Al and the alloy Sn85Cu15, where the selectivity for nitrogen formation was 43 and 35.3% at )1.8 and )2.0 V, respectively. The kinetic analysis of the experimental results was carried out by numerical solution of the resulted differential equations according to the scheme:The rate constants on Sn85Cu15 at )2.0 V for the above reactions were found to be k 1 ¼ 4:9 Â 10 À4 s )1 , k 2 ¼ 1:76 Â 10 À5 s )1 and k 3 ¼ 7:66 Â 10 À3 l mol )1 s )1 . At more negative potential more NO 2 ) ions reduced and converted either to N 2 or NH 3 . The rate constant of reduction of nitrate was almost the same in the region between )1.7 and )2.0 V, because the reaction is limited by the diffusion. In order to oxidize a part of the undesirable byproducts NO 2 ) and NH 3 at the anode of the cell to nitrate and nitrogen respectively, an undivided cell was used. Comparison between the two cell configurations indicated that, although in the undivided cell the % removal efficiency of nitrate was lower than that in the divided one, the selectivities of NO 2 ) and NH 3 were 4.8 and 2.2 times lower, respectively.

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Cited by 47 publications

References 1 publication

Kinetic Studies of the Electrochemical Treatment of Nitrate and Nitrite Ions on Iridium‐Modified Carbon Fiber Electrodes

Kinetic Studies of the Electrochemical Treatment of Nitrate and Nitrite Ions on Iridium‐Modified Carbon Fiber Electrodes

Mechanism of Nitric Acid Reduction and Kinetic Modelling

Electrochemical reduction of nitrate ion on various cathodes ? reaction kinetics on bronze cathode

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