CN1168979C - Nano COD sensor and its preparing process and usage - Google Patents
Nano COD sensor and its preparing process and usage Download PDFInfo
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- CN1168979C CN1168979C CNB021119708A CN02111970A CN1168979C CN 1168979 C CN1168979 C CN 1168979C CN B021119708 A CNB021119708 A CN B021119708A CN 02111970 A CN02111970 A CN 02111970A CN 1168979 C CN1168979 C CN 1168979C
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Abstract
The present invention relates to a nanometer COD sensor, the preparation of the sensor and the application for detecting COD value by the sensor to water analysis, which belongs to the fields of sensors, the preparation of the sensors and purposes thereof. Platinum or a valuable metal wire basal body is used as an anode. In a system of lead nitrate, nitric acid or perchloric acid and decorative liquid adulterating ions, a layer of nanometer beta-PbO2 of which the thickness is 0.01 to 0.1mm is decorated by a cyclic voltammetry electrochemical method, or beta-PbO2 is adulterated. The manufactured nanometer COD sensor has the advantages of high measuring accuracy, wide measuring range, no secondary pollution and short electrode response time, and can satisfy timely, quick and on-line requirements in environmental monitoring at present.
Description
Technical field
The present invention relates to a kind of nanochemistry oxygen demand (the international title of following usefulness " COD " expression) sensor, also relate to the preparation method of this nano COD sensor and this nano COD sensor is measured COD content in the water in water analysis application, belong to the preparation of sensor, sensor and the technical field of sensor applications.
Technical background
Chemical oxygen demand (COD) (COD) is to weigh a leading indicator of water pollution.At present, the COD method for measuring mainly contains standard law, coulometry, photometry.Standard law that is potassium dichromate method are state specified standards method (international standard ISO6066-86 (E), water quality: the mensuration of chemical oxygen demand (COD)).This method has to be measured accurately, the advantage of favorable reproducibility, but consume a large amount of concentrated sulphuric acids and expensive silver sulfate, in order to eliminate the interference of chlorion, also need add the great toxicity mercuric sulfate and be sheltered, and need high temperature to clear up, return time is long, minute is slower, generally needs 2 hours, is difficult to satisfy timely, quick, online requirement in the current environment monitoring.The methods such as coulometry, photometry of having developed are both at home and abroad subsequently measured COD, wherein coulometry is oxygenant with the potassium dichromate, behind the reflux oxidation, the ferrous ion that produces with electrolysis carries out coulometric titration as COULOMETRIC TITRANT in sulfuric acid medium, tries to achieve residue K according to the electric weight that consumes
2Cr
2O
7Amount, thus calculating COD value (Qi Wenqi etc., " Modern Scientific Instruments ", 1999,1-2,87-91); Photometry is with a certain amount of K
2Cr
2O
7, Ag
2SO
4With the concentrated sulphuric acid, HgSO
4Be blended in 75 ℃ of heating 15 minutes, its absorbance (Beliustin A A, Pisarevsky A M are surveyed in 600nm in the cooling back, et al.Sen.Actuators B, 1992, B10 (1): 61-66), though two kinds of methods are consuming time shortens greatly than standard law for this, but still need to use K
2Cr
2O
7, HgSO
4Deng toxic reagent, can produce secondary pollution, and need to clear up through high temperature, there is certain defective in the use.
In recent years, made the organism complete oxidation and the method that obtains organic substance concentration is developed with galvanochemistry at electrode surface.This method is the relation according to current value that electron exchange produced in the oxidizing process and measured matter concentration, the method for quantitatively determining of foundation.Lead dioxide electrode has good electrical conductivity, high overpotential and in acid-base solution good inertia, and obtained application in fields such as electrolysis, galvanochemistry are synthetic.Particularly in recent years in order to improve the electrode catalyst performance, nano-electrode has also obtained development widely.But relevant nano COD sensor and how to prepare the nano COD sensor of tool active structure and it is used for the application that water analysis detects the COD value as anode and do not see reported in literature as yet.
Technology contents
The object of the present invention is to provide a kind of nanostructured that has, the preparation method is simple, cheap nano COD sensor.
Another object of the present invention is to provide the preparation method of this nano COD sensor.
Another purpose of the present invention is to provide this nano COD sensor to measure the application of COD content in the water in water analysis.
Purpose of the present invention can realize by following technical proposal:
Nano COD sensor of the present invention is to be matrix with platinum or golden precious metal, is that thickness is the active nano modified metal oxide layer of 0.01-0.1 millimeter in the outside of precious metal matrix, and wherein nano-metal-oxide refers to nanometer β-PbO
2, the perhaps β-PbO of dopant ion
2, the ion of doping comprises Fe
3+, Co
2+, Mn
2+, Ce
3+, Cu
2+, Ni
2+, Bi (III), In (III), F
-, Cl
-, SO
4 2-, PO
4 3-
The preparation method of COD sensor of the present invention be with platinum or golden precious metal matrix after polishing, oxidation processes, do anode with it, in the decorating liquid system of plumbi nitras, nitric acid or perchloric acid, dopant ion, CONTROLLED POTENTIAL is at 1.0V-1.6V, 25 ℃-80 ℃ of decorating liquid temperature, be to electrode with the metal platinum filament, Ag/AgCl is that to modify a layer thickness with the cyclic voltammetric electrochemical method in the three-electrode system of contrast electrode be 0.01-0.1 millimeter nanometer β-PbO
2, β-PbO perhaps mixes
2, wherein dopant ion comprises Fe
3+, Co
2+, Mn
2+, Ce
3+, Cu
2+, Ni
2+, Bi (III), In (III), F
-, Cl
-, SO
4 2-, PO
4 3-, each composition is 5-30g/L for plumbi nitras concentration in the decorating liquid, and nitric acid or perchloric acid concentration are 0.004-1mol/L, and other dopant ion is 0.5-5g/L.
Nano COD sensor of the present invention can be used for detecting COD value in the water in water analysis.
Concrete application process is that this nano COD sensor is done anode, with sodium sulphate is electrolyte, CONTROLLED POTENTIAL 1.1V-1.4V, the standard solution that adds different COD values was read response current once in per 30 seconds, replicate determination 3 times, get the response curve of current value and COD, under identical working curve, when measuring the COD value of sewage, only need directly to get COD value in the water outlet according to the reading of electric current.
The present invention compared with prior art has following advantage:
1. the present invention provides a kind of nano COD sensor of modified metal oxide layer of nanostructured first, and its COD that is used for city and industrial sewage analysis is first measured.
2. nano COD sensor electrode activity height provided by the invention, the preparation method is simple, and electrode is cheap.
3. when nano COD sensor provided by the invention was done anode in determination of sewage, anode oxygen evolution potential height only produces OH and do not separate out oxygen under certain potentials, select OH productive rate height, and was thorough to oxidation operation, COD accuracy of measurement height, and measurement range is wide.
4. nano COD sensor provided by the invention does not use such as K in determination of sewage
2Cr
2O
7, HgSO
4Etc. poisonous, harmful chemical reagent, non-secondary pollution.
5. nano COD sensor provided by the invention electrode response time in determination of sewage only needs about 30 seconds, shortens greatly than the used time of prior art, can satisfy timely, quick and online requirement in the current environment monitoring.
Embodiment
Embodiment 1:
The preparation method of nano COD sensor is to be matrix with the noble metal platinum filament, with platinum filament with 0.01 micron CeO
2Powder is fully polishing on chamois leather, ultrasonic cleaning, in 1: 3 hydrogen peroxide and concentrated sulphuric acid mixed liquor, soaked 2 minutes, then with matrix as anode, at plumbi nitras, nitric acid is decorating liquid, and the metal platinum filament is to electrode, and Ag/AgCl is in the three-electrode system of contrast electrode, modify one deck nanometer particle size at 50-60nm through galvanochemistry, thickness is β-PbO of 0.1 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 30g/L in the decorating liquid of preparation nano COD sensor, and nitric acid is 1mol/L, and the modification current potential is 1.0V-1.6V, and temperature is 25 ℃, sweeps speed and is 40mV/s, and the modification time is 10 minutes.
Embodiment 2:
The preparation method of nano COD sensor is to be matrix with the noble metal spun gold, with spun gold with 0.01 micron CeO
2Powder is fully polishing on chamois leather, ultrasonic cleaning, in 1: 3 hydrogen peroxide and concentrated sulphuric acid mixed liquor, soaked 2 minutes, then with matrix as anode, at plumbi nitras, nitric acid, bismuth nitrate, sodium fluoride is decorating liquid, and the metal platinum filament is to electrode, and Ag/AgCl is in the three-electrode system of contrast electrode, modify one deck nanometer particle size about 100nm through galvanochemistry, thickness is bismuth doping β-PbO of 0.04 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 5g/L in the decorating liquid of preparation nano COD sensor, and nitric acid is 0.05mol/L, and bismuth nitrate is 2.5g/L, and sodium fluoride is 0.5g/L, and the modification current potential is 1.0-1.6V, and temperature is 50 ℃, sweeps speed and is 100mV/s, and the modification time is 6 minutes.
Embodiment 3:
The preparation method of nano COD sensor is to be matrix with the noble metal platinum filament, as embodiment 1 through polishing, cleaning and oxidation processes, then with matrix as anode, at plumbi nitras, nitric acid, cerous nitrate is decorating liquid, the metal platinum filament is to electrode, Ag/AgCl is in the three-electrode system of contrast electrode, and galvanochemistry is modified one deck nanometer particle size about 40-50nm, and thickness is cerium doping β-PbO of 0.04 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 15g/L in the decorating liquid of preparation nano COD sensor, and perchloric acid is 0.01mol/L, and cerous nitrate is 1.5g/L, and the modification current potential is 1.0-1.6V, and temperature is 25 ℃, sweeps speed and is 100mV/s, and the modification time is 6 minutes.
Embodiment 4:
The preparation method of nano COD sensor is to be matrix with the noble metal platinum filament, as embodiment 1 through polishing, cleaning and oxidation processes, then with matrix as anode, at plumbi nitras, perchloric acid, copper nitrate, sodium fluoride is decorating liquid, the metal platinum filament is to electrode, Ag/AgCl is in the three-electrode system of contrast electrode, modifies one deck nanometer particle size about 100nm through galvanochemistry, and thickness is doping β-PbO of 0.04 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 25g/L in the decorating liquid of preparation nano COD sensor, and perchloric acid is 0.05mol/L, and copper nitrate is 3g/L, and sodium fluoride is 0.5g/L, and the modification current potential is 1.0V-1.6V, and temperature is 50 ℃, sweeps speed and is 100mV/s, and the modification time is 5 minutes.
Embodiment 5:
The preparation method of nano COD sensor is to be matrix with the noble metal platinum filament, as embodiment 1 through polishing, cleaning and oxidation processes, then with matrix as anode, at plumbi nitras, nitric acid, iron ammonium sulfate is decorating liquid, the metal platinum filament is to electrode, Ag/AgCl is in the three-electrode system of contrast electrode, and galvanochemistry is modified one deck nanometer particle size at 70-80nm, and thickness is doping β-PbO of 0.06 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 10g/L in the decorating liquid of preparation nano COD sensor, and nitric acid is 0.004mol/L, and iron ammonium sulfate is 5g/L, and the modification current potential is 1.0V-1.6V, and temperature is 80 ℃, sweeps speed and is 100mV/s, and the modification time is 6 minutes.
Embodiment 6:
The preparation method of nano COD sensor is to be matrix with the noble metal platinum filament, as embodiment 1 through polishing, cleaning and oxidation processes, then with matrix as anode, at plumbi nitras, nitric acid, manganese chloride is decorating liquid, the metal platinum filament is to electrode, Ag/AgCl is in the three-electrode system of contrast electrode, and galvanochemistry is modified one deck nanometer particle size at 70-80nm, and thickness is doping β-PbO of 0.08 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 15g/L in the decorating liquid of preparation nano COD sensor, and nitric acid is 0.004mol/L, and manganese chloride is 2g/L, and the modification current potential is 1.0-1.6V, and temperature is 25 ℃, sweeps speed and is 40mV/s, and the modification time is 6 minutes.
Embodiment 7:
The preparation method of nano COD sensor is to be matrix with the noble metal platinum filament, as embodiment 1 through polishing, cleaning and oxidation processes, then with matrix as anode, at plumbi nitras, perchloric acid, nickel chloride is decorating liquid, the metal platinum filament is to electrode, Ag/AgCl is in the three-electrode system of contrast electrode, and galvanochemistry is modified one deck nanometer particle size at 50-60nm, and thickness is doping β-PbO of 0.06 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 10g/L in the decorating liquid of preparation nano COD sensor, and perchloric acid is 0.05mol/L, and nickel chloride is 2.5g/L, and the modification current potential is 1.0V-1.6V, and temperature is 50 ℃, sweeps speed and is 100mV/s, and the modification time is 8 minutes.
Embodiment 8:
The preparation method of nano COD sensor is to be matrix with the noble metal spun gold, as embodiment 1 through polishing, cleaning and oxidation processes, then with matrix as anode, at plumbi nitras, nitric acid, cobalt nitrate, sodium dihydrogen phosphate is decorating liquid, the metal platinum filament is to electrode, Ag/AgCl is in the three-electrode system of contrast electrode, and galvanochemistry is modified one deck nanometer particle size at 70-80nm, and thickness is doping β-PbO of 0.04 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 25g/L in the decorating liquid of preparation nano COD sensor, and nitric acid is 0.1mol/L, and cobalt nitrate is 5g/L, and sodium dihydrogen phosphate is 0.5g/L, and the modification current potential is 1.0V-1.6V, and temperature is 25 ℃, sweeps speed and is 60mV/s, and the modification time is 10 minutes.
Embodiment 9:
The preparation method of nano COD sensor is to be matrix with the noble metal platinum filament, as embodiment 1 through polishing, cleaning and oxidation processes, then with matrix as anode, at plumbi nitras, nitric acid, indium nitrate is decorating liquid, the metal platinum filament is to electrode, Ag/AgCl is in the three-electrode system of contrast electrode, and galvanochemistry is modified one deck nanometer particle size at 70-80nm, and thickness is doping β-PbO of 0.01 millimeter
2, promptly make nano COD sensor.Plumbi nitras is 10g/L in the decorating liquid of preparation nano COD sensor, and nitric acid is 0.01mol/L, and indium nitrate is 5g/L, and the modification current potential is 1.0V-1.6V, and temperature is 25 ℃, sweeps speed and is 60mV/s, and the modification time is 6 minutes.
Embodiment 10:
With nano COD sensor prepared among the embodiment 1, measure certain hospital sewage, this sewage contains a large amount of bacteriums, virus, parasitic ovum and some poisonous and harmful substances.Its assay method is to be anode with the nano COD sensor, is electrolyte with 0.01mol/L sodium sulphate, CONTROLLED POTENTIAL 1.1V, add different COD standard solution, read response current once in per 30 seconds, replicate determination 3 times, get the response curve of current value and COD, the working curve coefficient R
2=0.9905.Under working curve the same terms, the COD value of measuring hospital sewage is 156mg/L.
Embodiment 11:
With nano COD sensor prepared among the embodiment 5, measure certain brewery's sewage, this sewage mainly contains carbohydrate, pure type organic, and its assay method is to be anode with the nano COD sensor, is electrolyte with 0.01mol/L sodium sulphate, CONTROLLED POTENTIAL 1.4V, add the standard C OD solution of variable concentrations, read response current once in per 30 seconds, replicate determination 3 times, get the response curve of current value and COD, the working curve coefficient R
2=0.9941, and the COD value of measuring in brewery's sewage is 850mg/L.
Embodiment 12:
With nano COD sensor prepared among the embodiment 8, measure certain pharmaceutical factory's sewage, this sewage mainly contains amine, phenol organic matter.Its assay method is to be anode with the nano COD sensor, is electrolyte with 0.01mol/L sodium sulphate, CONTROLLED POTENTIAL 1.2V, add the standard C OD solution of variable concentrations, read response current once in per 30 seconds, replicate determination 3 times, get the response curve of current value and COD, the working curve coefficient R
2=0.9949.Under working curve the same terms, the COD value of measuring in certain pharmaceutical factory sewage is 1652mg/L.
Claims (3)
1. nanochemistry oxygen demand sensor, with platinum or golden precious metal is matrix, it is characterized in that: be that thickness is the active nano modified metal oxide layer of 0.01-0.1 millimeter in the outside of precious metal matrix, wherein nano-metal-oxide refers to nanometer β-PbO
2, the perhaps β-PbO of dopant ion
2, the ion of doping comprises Fe
3+, Co
2+, Mn
2+, Ce
3+, Cu
2+, Ni
2+, Bi (III), In (III), F
-, Cl
-, SO
4 2-, PO
4 3-
2. the preparation method of a nanochemistry oxygen demand sensor is characterized in that: with platinum or golden precious metal matrix with 0.01 micron CeO
2Powder is fully polishing on chamois leather, ultrasonic cleaning, in 1: 3 hydrogen peroxide and concentrated sulphuric acid mixed liquor, soak after 2 minutes, do anode with it, in the decorating liquid system of plumbi nitras, nitric acid or perchloric acid, dopant ion, CONTROLLED POTENTIAL is at 1.0V-1.6V, 25 ℃-80 ℃ of decorating liquid temperature, be to electrode with the metal platinum filament, Ag/AgCl modifies the nanometer β that a layer thickness is the 0.01-0.1 millimeter-PbO with the cyclic voltammetric electrochemical method in the three-electrode system of contrast electrode
2, the perhaps β-PbO of dopant ion
2, wherein dopant ion comprises Fe
3+, Co
2+, Mn
2+, Ce
3+, Cu
2+, Ni
2+, Bi (III), In (III), F
-, Cl
-, SO
4 2-, PO
4 3-, each composition is 5-30g/L for plumbi nitras concentration in the decorating liquid, and nitric acid or perchloric acid concentration are 0.004-1mol/L, and other dopant ion is 0.5-5g/L.
3. a nanochemistry oxygen demand sensor detects the application of chemical oxygen demand value in the water in water analysis.
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|---|---|---|---|
| CNB021119708A CN1168979C (en) | 2002-06-07 | 2002-06-07 | Nano COD sensor and its preparing process and usage |
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|---|---|---|---|
| CNB021119708A CN1168979C (en) | 2002-06-07 | 2002-06-07 | Nano COD sensor and its preparing process and usage |
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| CN1168979C true CN1168979C (en) | 2004-09-29 |
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| CN1975400B (en) * | 2006-09-29 | 2010-05-12 | 华东师范大学 | Apparatus for measuring chemical oxyger requirement by photoelectric concerted catalysis |
| CN101105472B (en) * | 2007-06-11 | 2010-05-19 | 大连理工大学 | Water body chemical oxygen demand electrochemical measuring method |
| CN109281347B (en) * | 2018-08-24 | 2020-11-13 | 江苏华洋新思路能源装备股份有限公司 | Automatic water changing method of automatic water changing device of nuclear power unit |
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