GB2108529A - Electrochemically decomposing nitric acid - Google Patents
Electrochemically decomposing nitric acid Download PDFInfo
- Publication number
- GB2108529A GB2108529A GB08222443A GB8222443A GB2108529A GB 2108529 A GB2108529 A GB 2108529A GB 08222443 A GB08222443 A GB 08222443A GB 8222443 A GB8222443 A GB 8222443A GB 2108529 A GB2108529 A GB 2108529A
- Authority
- GB
- United Kingdom
- Prior art keywords
- nitric acid
- silver
- nitrous oxide
- cathode
- silver ions
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
- C02F1/4676—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electroreduction
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/04—Treating liquids
- G21F9/06—Processing
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/163—Nitrates
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Electrochemistry (AREA)
- High Energy & Nuclear Physics (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Abstract
The present invention relates to a method for electrochemically decomposing or reducing nitric acid in an electrolysis cell with the extensive or exclusive formation of nitrous oxide (dinitrogen monoxide), the method being carried out in the presence of silver or silver ions. The method is particularly intended for use in removing nitric acid from moderately or highly radioactive waste solutions produced during the reprocessing of nuclear fuels.
Description
SPECIFICATION
Method for electrochemically decomposing nitric acid
The present invention relates to a method for electrochemically decomposing nitric acid with the extensive or exclusive formation of nitrous oxide (dinitrogen monoxide). The present invention relates, in particular, to a method which can be used for removing nitric acid from moderately or highly radioactive waste solutions produced during the reprocessing of nuclear fuels.
During the reprocessing of nuclear fuels, any free nitric acid must be removed from solutions of waste containing a plurality of fission products in nitric acid because the presence of free nitric acid during the subsequent solidification of the fission products cannot be tolerated. Simple neutralisation of the acid is not possible because it would cause the volume of the waste to be increased drastically. Chemical methods of reducing nitric acid, for example, using formic acid, are known in the art. It is also known to reduce nitric acid electrochemically to form gaseous products. The literature describing such electrochemical reduction methods includes: H.
Schmieder, F. Baumgaertner: Radiochimica
Acta 25, 191 (1978); H. Schmieder, E. Warnecke, H. Goldacker, A. Hollmann: KfK, PWA
Bericht 23/75; H. Schmieder, F. Baumgaertner H. Goldacker, H. Hausberger: KfK-Bericht 2082; D.L. Barney: General Electric Rep.
KAPL 1263 (1955); J.A. Epstein, l. Levin, S.
Raviv: Electrochim. Acta 9, 1665 (1964); and
G. Facsko, G. Golumbioschi: Electrochim.
Acta 12, 1495 (1967).
The cathodes used in these experiments were made of graphite, platinum or titanium.
Depending on the experimental conditions, nitric oxide, nitrous oxide, nitrogen dioxide or ammonia are the resultant gaseous products.
Any ammonia which is produced remains in the electrolyte in the form of ammonium ions.
An exact amount of 50% nitrous oxide is briefly obtained during electrolysis in only one described case. In all of the other described reports, nitric oxide and nitrogen dioxide are the main gaseous products. Any nitrogen dioxide produced is usually formed by reacting the nitric oxide formed at the cathode with the oxygen formed at the anode, copper ions are added to the electrolyte, the electrochemical reduction is accelerated, but there is a concomitant intensified formation of ammonia. The addition of titanium ions also has a similar acclerating effect.
Since the formation of nitric oxide and nitrogen dioxide necessitates the use of very expensive waste gas purifying plants, it is desirable to effect the electrochemical reduction of nitric acid in such a manner that, were possible, inert products such as nitrous oxide or nitrogen are produced. There is no mention in the literature of the direct formation of nitrogen by the cathodic reduction of nitric acid and indeed we have not found it possible to prove the formation of N2 under experimental conditions.
The present invention seeks to provide an electrochemical method of decomposing or reducing nitric acid which leads to the extensive, or even exclusive, formation of nitrous oxide.
In accordance with the present invention, there is provided a method for the electrochemica decomposition or reduction of nitric acid in an electrolytic cell to produce extensively or exclusively nitrous oxide (dinitrogen monoxide) wherein the decomposition reaction is carried out in the presence of silver or silver ions. If silver ions are not already present, in the aqueous nitric acid-containing solution to be electrolysed, silver ions may be added to the nitric acid to be decomposed or reduced prior to the electrolysis being effected. Since silver ions are reduced during the electrolysis of nitric acid and are deposited in metallic form, on the cathode, the cathode may also be made of silver.In one advantageous embodiment of the present invention, the electrodes forming the cathodes, prior to being used for the decomposition reaction, are coated with silver, preferably electrochemically. The electrochemical reduction of nitric acid, having selectivity well in excess of 50%, to form-nitrous oxide (dinitrogen monoxide) may thus be effected utilising silver electrodes, silver-coated electrodes, or in the presence of silver ions in the electrolyte. By so doing, the formation of other gaseous products is largely suppressed.
The method according to the present invention does not require the use of a specially designed electrolysis cell. The decomposition or reduction of the nitric acid may be successfully effected both in an undivided cell and in a a cell which is divided by means of a porous diaphragm or an ion exchange membrane.
The electrodes, particularly the cathodes, may be in the form of nets, lattices or plates or any other suitable form. Fixed bed electrodes or spin bed electrodes may also be used as the electrodes, particularly as the cathode.
The method of the present invention and the results achieved thereby will now be described in greater detail, by way of illustration only, with reference to the following Examples. The results obtained from experiments utilising known procedures are given for comparison purposes.
Example 1: a) Known procedure
An electrochemical electrolysis cell having a platinum anode and a plate-shaped graphite cathode is employed. If unimolar nitric acid is reduced in such a cell, the cell being divided,
with potentiostatic control at a cathode poten
tial of O mV compared with a standard hydro
gen electrode; the only reduction product woud be nitric oxide because the reaction of this substance with the anodic oxygen is prevented by the divider.
b) Known procedure
In the electrolysis cell utilised in (a) above, a a unimolar solution of nitric acid is electro
lysed potentiostatically at a cathode potential
of - 450 mV compared with a standard
hydrogen electrode. In a series of experi
ments, over a four hour period, the percentages of the gases produced were 71 % hydro- gen, 2% nitric oxide, 15% nitrous oxide and 12% ammonia.
c) Method according to the present invention:
The experiment described in (b) was repeated at a cathode potential of - 59 mV compared with a standard hydrogen electrode.
In addition, however, 8.10-5 mol/litre silver
ions were added to the electrolyte prior to the commencement of the electrolysis. In this case, the percentages of the gases produced were 97% nitrous oxide, 2% ammonia and traces of hydrogen and nitric oxide.
Example 2: (a) Known procedure:
Instead of the graphite cathode used in
Example 1 (a) and (b), a cathode made of sheet titanium was used. Unimolar nitric acid was electrolysed for a period of four hours in this cell with potentiostatic control at - 359 mV compared with a standard hydrogen electrode. On average, the percentages of gases produced were 55% nitric oxide and 45% nitrous oxide.
(b) Method according to the present invention:
The experiment described in Example 2 (a) above was repeated but with the addition of 8.10-5 mol/litre silver ions to the electrolyte prior to the commencement of the electrolysis.
By utilising this procedure, the percentages of the gases produced were 22% nitric oxide, 74% nitrous oxide and 4% ammonia.
Claims (6)
1. A method for the electrochemical decomposition or reduction of nitric acid in an electrolytic cell to produce extensively or exclusively nitrous oxide (dinitrogen monoxide) wherein the decomposition reaction is carried out in the presence of silver or silver ions.
2. A method as claimed in claim 1, wherein silver ions are added to the nitric acid to be decomposed or reduced prior to electrolysis.
3. A method as claimed in claim 1, wherein silver is used as the cathode material in the electrolytic cell.
4. A method as claimed in claim 1, wherein the electrodes which form the cathodes are formed from materials which have been coated with silver.
5. A method as claimed in claim 4, wherein the coating of the cathode with silver is effected electrochemically.
6. A method as claimed in claim 1, substantially as hereinbefore described and as illustrated in Example 1(c) or 2(b).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19813135195 DE3135195A1 (en) | 1981-09-05 | 1981-09-05 | METHOD FOR THE ELECTROCHEMICAL DECOMPOSITION OF Nitric Acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2108529A true GB2108529A (en) | 1983-05-18 |
| GB2108529B GB2108529B (en) | 1985-01-30 |
Family
ID=6140943
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08222443A Expired GB2108529B (en) | 1981-09-05 | 1982-08-04 | Electrochemically decomposing nitric acid |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE3135195A1 (en) |
| FR (1) | FR2512431B1 (en) |
| GB (1) | GB2108529B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2289898A (en) * | 1994-06-04 | 1995-12-06 | Atomic Energy Authority Uk | Reducing contamination of the anolyte in electrochemical oxidation of matter using nitric acid containing silver ions as the electrolyte |
| US5855763A (en) * | 1994-06-04 | 1999-01-05 | Aea Technology Plc | Electrochemical oxidation of matter |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3805741A1 (en) * | 1987-11-14 | 1989-06-01 | Wiederaufarbeitung Von Kernbre | METHOD AND DEVICE FOR THE ELECTROCHEMICAL DECOMPOSITION OF INORGANIC INGREDIENTS OF AN AQUEOUS, RADIOACTIVE WASTE SOLUTION |
| GB2250853B (en) * | 1990-08-31 | 1994-05-18 | Nikki Kabushiki Kaisha | Method of treating nitric acid recovered from spent nuclear fuel reprocessing process |
| US20150291451A1 (en) * | 2012-10-12 | 2015-10-15 | Council Of Scientific & Industrial Research | Electrochemical system and process for the reduction of nitric acid concentration using electrolytic cell |
| WO2014057505A1 (en) * | 2012-10-12 | 2014-04-17 | Council Of Scientific & Industrial Research | An electrochemical system and process for the reduction of nitric acid concentration using electrolytic cell |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2449588C2 (en) * | 1974-10-18 | 1985-03-28 | Kernforschungszentrum Karlsruhe Gmbh, 7500 Karlsruhe | Process for the decomposition of an aqueous, radioactive waste solution with dissolved, inorganic and organic substances |
| DE2811517A1 (en) * | 1978-03-16 | 1979-09-20 | Szmuel Dr Reznik | PROCESS FOR GENERATING INTERFACIAL ENERGY BY ELECTROLYTIC-THERMAL SEPARATION OF WATER, AQUATIC SYSTEMS OR ORGANIC SYSTEMS |
| DE3047988C2 (en) * | 1980-12-19 | 1982-11-04 | Kernforschungszentrum Karlsruhe Gmbh, 7500 Karlsruhe | Process for reducing the acid content of a nitric acid solution using an electrolysis current and device for carrying out the process |
-
1981
- 1981-09-05 DE DE19813135195 patent/DE3135195A1/en not_active Withdrawn
-
1982
- 1982-08-04 GB GB08222443A patent/GB2108529B/en not_active Expired
- 1982-08-31 FR FR8214901A patent/FR2512431B1/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2289898A (en) * | 1994-06-04 | 1995-12-06 | Atomic Energy Authority Uk | Reducing contamination of the anolyte in electrochemical oxidation of matter using nitric acid containing silver ions as the electrolyte |
| GB2289898B (en) * | 1994-06-04 | 1997-08-06 | Atomic Energy Authority Uk | Electrochemical oxidation of matter |
| US5855763A (en) * | 1994-06-04 | 1999-01-05 | Aea Technology Plc | Electrochemical oxidation of matter |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2108529B (en) | 1985-01-30 |
| FR2512431A1 (en) | 1983-03-11 |
| FR2512431B1 (en) | 1986-05-09 |
| DE3135195A1 (en) | 1983-03-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |