CN112834721A - Based on UV/H2O2Method and device for detecting COD (chemical oxygen demand) of water quality by technology - Google Patents
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 62
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims description 31
- 239000001301 oxygen Substances 0.000 title claims description 31
- 229910052760 oxygen Inorganic materials 0.000 title claims description 31
- 238000005516 engineering process Methods 0.000 title description 7
- 239000000126 substance Substances 0.000 title description 6
- 238000000034 method Methods 0.000 claims abstract description 36
- 230000029087 digestion Effects 0.000 claims abstract description 26
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 72
- 239000007789 gas Substances 0.000 claims description 57
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 52
- 238000006243 chemical reaction Methods 0.000 claims description 47
- 239000001569 carbon dioxide Substances 0.000 claims description 26
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 26
- 239000007788 liquid Substances 0.000 claims description 18
- 238000001035 drying Methods 0.000 claims description 13
- 239000000243 solution Substances 0.000 claims description 13
- 238000002347 injection Methods 0.000 claims description 12
- 239000007924 injection Substances 0.000 claims description 12
- 239000002699 waste material Substances 0.000 claims description 11
- 239000008367 deionised water Substances 0.000 claims description 10
- 229910021641 deionized water Inorganic materials 0.000 claims description 10
- 230000000087 stabilizing effect Effects 0.000 claims description 10
- 238000001514 detection method Methods 0.000 claims description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 238000004364 calculation method Methods 0.000 claims description 5
- 238000007599 discharging Methods 0.000 claims description 4
- 230000006641 stabilisation Effects 0.000 claims 1
- 238000011105 stabilization Methods 0.000 claims 1
- 230000001590 oxidative effect Effects 0.000 abstract description 6
- 125000002887 hydroxy group Chemical group [H]O* 0.000 abstract description 5
- 239000007800 oxidant agent Substances 0.000 abstract description 3
- 239000013307 optical fiber Substances 0.000 abstract 1
- 230000002195 synergetic effect Effects 0.000 abstract 1
- 239000010865 sewage Substances 0.000 description 22
- 239000000523 sample Substances 0.000 description 19
- 230000003647 oxidation Effects 0.000 description 8
- 238000007254 oxidation reaction Methods 0.000 description 8
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 8
- 239000002351 wastewater Substances 0.000 description 8
- 238000010561 standard procedure Methods 0.000 description 7
- 239000010842 industrial wastewater Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 238000002133 sample digestion Methods 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000004939 coking Methods 0.000 description 2
- 239000012488 sample solution Substances 0.000 description 2
- 238000002798 spectrophotometry method Methods 0.000 description 2
- 238000004448 titration Methods 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- 238000003911 water pollution Methods 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910001430 chromium ion Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 230000033116 oxidation-reduction process Effects 0.000 description 1
- 231100001239 persistent pollutant Toxicity 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/18—Water
- G01N33/1806—Biological oxygen demand [BOD] or chemical oxygen demand [COD]
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
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Abstract
The invention discloses a UV/H-based optical fiber2O2The method and the device for detecting the COD of water quality technically are based on UV/H2O2Under the synergistic effect, a large amount of hydroxyl free radicals with strong oxidizing property can be generated, organic matters are oxidized and decomposed, and COD is calculated by detecting the consumption of the oxidant after digestion is finished.
Description
Technical Field
The invention relates to a method and a device for detecting COD (chemical oxygen demand), belonging to the technical field of water quality detection.
Background
In recent years, the industry of China keeps developing at a high speed, the industrial scale is continuously enlarged, the economic construction is continuously improved, and the material life of people is richer. Meanwhile, more and more industrial wastewater and domestic sewage are discharged into rivers and lakes. As the problem of water environment pollution caused by the discharge of industrial wastewater and domestic sewage becomes more serious, corresponding water pollution events emerge endlessly. The total amount of wastewater discharged nationwide in 2017 is 6996610 ten thousand tons as reported in the annual book of China (2019), wherein the total amount of wastewater discharged in cities and towns exceeds 70% of the total amount of wastewater discharged all the year round. With the continuous development of the economy of China, the process of urbanization is continuously promoted, and the domestic sewage of cities and towns becomes a main source for continuously increasing the discharge amount of the wastewater of China. According to the average increasing rate of 6% in 2011-2015, the increasing rate of 6% of the urban domestic sewage discharge in 2016-2020 is measured. Although the discharge amount of the industrial wastewater is reduced by 2 percent all the time, the base number of the discharge amount of the industrial wastewater is still huge.
Water quality monitoring is an important means for pollution pre-confusion, persistent pollutant monitoring and treatment effect assessment. As the most commonly measured item in water quality monitoring and analysis, Chemical Oxygen Demand (COD) is one of the important indicators for evaluating water pollution. COD is a characteristic index which has practical significance and is relatively easy to measure for evaluating the polluted conditions of rivers and lakes and the treatment effect of organic wastewater.
At present, the method for detecting the COD content of the water body mainly adopts a national standard potassium dichromate method (GB 11914-89) and an industry standard rapid digestion spectrophotometry method (HJ/T399-. CN201811405123.8 discloses an on-line detection method for COD in organic wastewater, and the principle is also based on the design of an on-line detection device by the traditional national standard method. The national standard method is that a known amount of potassium dichromate solution is added into a water sample, the organic water sample is subjected to high-temperature reflux oxidation digestion under an acidic or alkaline medium, and then the COD value is indirectly calculated by chemical titration quantification. The fast digestion spectrophotometry method is a method for detecting chromium ions in potassium dichromate by using a spectrophotometer on the basis of a national standard method, replaces a traditional chemical titration method, calculates a COD value by using the method, but the two methods have many problems in actual operation, including long time consumption for measurement, complex steps, addition of toxic and expensive chemical reagents, high energy consumption and environmental friendliness. How to detect COD more efficiently and harmlessly becomes a problem to be researched and solved by researchers.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a UV/H-based UV/H2O2The method for detecting the COD in the water quality by the technology can realize the high efficiency of the COD detection, has the advantages of low cost, low environmental hazard and the like, and uses UV/H2O2The technology is applied to a COD digestion stage, and the digestion speed and the digestion completion degree can be effectively improved; after digestion was completed, COD was calculated by detection of oxidant consumption. UV/H2O2The technology belongs to one of advanced oxidation, mainly converts organic matters into water and carbon dioxide, obtains a COD value by combining the consumption of hydrogen peroxide with corresponding calculation, and can judge whether digestion is finished or not by detecting the generation amount of carbon dioxide and oxygen.
The method comprises the following specific steps:
(1) introducing a water sample to be detected and hydrogen peroxide liquid with the concentration of 50mmol/L into a reaction tube under the irradiation of a 254nm ultraviolet lamp, digesting the water sample in the reaction tube, increasing the pressure value in the reaction tube by using gas generated in the digestion reaction process, discharging the generated gas from an exhaust pipe at the other end of the reaction tube, condensing and drying, continuously detecting the concentration, the gas flow, the temperature, the pressure and the oxygen concentration of detected carbon dioxide generated in the reaction process, discharging the gas into a tail gas treatment pool, finishing the reaction when the carbon dioxide is not detected in the gas, and determining the hydrogen peroxide content in the digested solution;
(2) calculation of COD
The total amount of hydrogen peroxide added to the reaction tube is M1The residual amount of hydrogen peroxide in the solution after digestion is M2During the reaction, part of the hydrogen peroxide is converted into oxygen, and the amount of the partially converted hydrogen peroxide is M3；
The calculation formula of COD is as follows:
wherein 3.043 is the oxygen reduction coefficient.
And introducing the hydrogen peroxide solution into the reaction container at a constant flow rate through a constant flow pump, and stopping injection to wait for the digestion reaction to be carried out when the concentration of the carbon dioxide begins to decrease. When digestion is completed, the concentration of carbon dioxide is reduced to the minimum, and the concentration of oxygen begins to increase, so that whether the digestion reaction is ended or not can be judged.
The digestion process is based on UV/H2O2Advanced oxidation technique, under UV radiation, H2O2The water sample digestion system can be directly decomposed to generate hydroxyl free OH, the hydroxyl free OH has strong oxidizability, the oxidation-reduction potential is as high as 2.80V, the water sample digestion system has stronger oxidation capacity than potassium dichromate, the hydroxyl free OH with strong oxidizability can be used for carrying out effective oxidation digestion on a water sample, the hydroxyl free OH is used as a main oxidant in the water sample digestion process to react with organic matters in the water sample, and the organic matters are mainly digested into carbon dioxide and water.
Because the decomposition rate of the hydrogen peroxide is seriously reduced by the ultrahigh COD solution, the method is only suitable for detecting the COD concentration of 30-600 mg/L, and the ultrahigh COD solution can be diluted first and then detected.
The above-mentioned
Wherein V is the volume of the solution after digestion,
is the hydrogen peroxide concentration in the solution after digestion.
The instantaneous oxygen concentration in ppm is converted to mg/L by the formula:
wherein M is the molar quantity of oxygen, and 22.4 is an ideal gas volume constant; 1000 is the ratio of mg/m3Conversion to a factor of mg/L; 273.15 is the Kelvin temperature under standard conditions, K; 101.325 is the pressure under standard conditions, KPa; t is the detected temperature, DEG C; p is the detected pressure, KPa;C 1is the instantaneous oxygen concentration, ppm.
The invention also provides a device for completing the method, which comprises a deionized water storage tank, a hydrogen peroxide solution storage tank, a to-be-detected water sample storage tank, a three-way electromagnetic valve I, a three-way electromagnetic valve II, an injection pump, a constant flow pump, a reaction tube, an ultraviolet lamp, a drying and condensing device, a pressure-reducing and stabilizing valve, a needle valve, a gas flow sensor, a pressure sensor, a temperature sensor, an oxygen sensor, a carbon dioxide concentration sensor, an electromagnetic valve and a waste liquid treatment pool, wherein the ultraviolet lamp is arranged around the outer side of the reaction tube, the deionized water storage tank and the hydrogen peroxide solution storage tank are communicated with the constant flow pump through the three-way electromagnetic valve I and a pipeline, the deionized water storage tank and the to-be-detected water sample storage tank are communicated with the injection pump through the three-way electromagnetic valve II and the pipeline, the injection pump and the constant flow pump are respectively communicated with a liquid inlet, the drying and condensing device is communicated with the tail gas treatment tank through a pipeline, a pressure reducing and stabilizing valve, a needle valve, a gas flow sensor, a pressure sensor, a temperature sensor, an oxygen sensor and a carbon dioxide concentration sensor are sequentially arranged on the pipeline, a liquid outlet at the other end of the reaction tube is connected with the waste liquid treatment tank through an electromagnetic valve and the pipeline, and a hydrogen peroxide sensor is arranged on the pipeline.
The reaction tube is a quartz glass reactor.
The invention has the following advantages and effects:
1) by UV/H2O2The advanced oxidation digestion technology can quickly and effectively oxidize and digest most of organic matters in a water sample in a short time, and has high oxidation efficiency;
2) in the whole oxidation digestion process, toxic or expensive chemical reagents are not required to be added, so that the cost is low, secondary pollution is avoided, and the environmental hazard is small;
3) the measuring method is simple and easy to understand, insensitive to the influence of chloride and accurate and reliable in result;
4) the whole measuring process can be automatically controlled by utilizing an automation technology, and the operation is simple and convenient.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention;
in the figure: 1-deionized water storage tank; 2-a hydrogen peroxide solution storage tank; 3-a water sample storage tank to be detected; 4-three-way electromagnetic valve I; 5-three-way electromagnetic valve II; 6-a syringe pump; 7-a constant flow pump; 8-a reaction tube; 9-an ultraviolet lamp; 10-a drying and condensing device; 11-a pressure reducing and stabilizing valve; 12-needle type valve; 13-a gas flow sensor; 14-a pressure sensor; 15-a temperature sensor; 16-an oxygen sensor; 17-a carbon dioxide concentration sensor; 18-a tail gas treatment tank; 19-a solenoid valve; 20-hydrogen peroxide sensor; 21-a waste liquid treatment tank.
Detailed Description
The present invention is further illustrated by the following examples, but the scope of the invention is not limited to the above-described examples.
Example 1: the ultraviolet/H-based2O2The method for technically detecting the COD of the sewage at the water inlet of a certain sewage treatment plant comprises the following steps:
the device shown in figure 1 is adopted, and comprises a deionized water storage tank 1, a hydrogen peroxide solution storage tank 2, a water sample storage tank 3 to be tested, a three-way electromagnetic valve I4, a three-way electromagnetic valve II 5, an injection pump 6, a constant flow pump 7, a reaction tube 8, an ultraviolet lamp 9, a drying and condensing device 10, a pressure reducing and stabilizing valve 11, a needle valve 12, a gas flow sensor 13, a pressure sensor 14, a temperature sensor 15, an oxygen sensor 16, a carbon dioxide concentration sensor 17, an electromagnetic valve 19 and a waste liquid treatment pool 21, wherein the ultraviolet lamp 9 is arranged around the outer side of the reaction tube 8, the deionized water storage tank 1 and the hydrogen peroxide solution storage tank 2 are communicated with the constant flow pump 7 through the three-way electromagnetic valve I4 and a pipeline, the deionized water storage tank 1 and the water sample storage tank 3 to be tested are communicated with the injection pump 6 through the three-way electromagnetic valve II 5 and the pipeline, the injection pump 6 and the, The liquid inlet II is communicated, the gas outlet at the other end of the reaction tube 8 is connected with a drying and condensing device 10, the drying and condensing device 10 is communicated with a tail gas treatment pool 18 through a pipeline, a pressure reducing and stabilizing valve 11, a needle valve 12, a gas flow sensor 13, a pressure sensor 14, a temperature sensor 15, an oxygen sensor 16 and a carbon dioxide concentration sensor 17 are sequentially arranged on the pipeline, the liquid outlet at the other end of the reaction tube 8 is connected with a waste liquid treatment pool 21 through an electromagnetic valve 19 and the pipeline, and a hydrogen peroxide sensor 20 is arranged on the pipeline.
Collecting a sewage sample at a water inlet of a sewage treatment plant, pouring the sewage sample into a to-be-detected water sample storage tank 3, filling hydrogen peroxide liquid with the concentration of 50mmol/L into a hydrogen peroxide solution storage tank 2, and ensuring that enough hydrogen peroxide solution is used for digestion; under the light of 254nm ultraviolet light, 20mL of water sample solution is pumped into a reaction tube 8 of quartz glass by an injection pump; setting a hydrogen peroxide solution to be introduced into the reaction tube at a constant flow rate of 0.05mL/min, if carbon dioxide is not obviously reduced after 8min, changing the hydrogen peroxide solution to be introduced into the reaction tube at a constant flow rate of 0.1mL/min, stopping introducing the hydrogen peroxide when the generation amount of the carbon dioxide is obviously reduced, and waiting for the water sample to be completely digested;
H2O2hydroxyl radicals (OH) with strong oxidizing property are generated under UV radiation, organic matters in the coking wastewater are oxidized and decomposed into carbon dioxide by the hydroxyl radicals, the generated carbon dioxide is discharged from one end of the quartz glass reaction tube, moisture in the gas is removed by a gas drying and condensing device, and the gas can have stable pressure through subsequent equipment by a pressure reducing and stabilizing valve 11 and a needle valve 12. Then, the gas passes through a needle valve to ensure that the gas passes through an FS4001 gas flow sensor 13, an YB-131 pressure sensor 14, a DS18b20 temperature sensor 15, a CLE-0231 and 400 oxygen sensor 16 and a T6615-50KF carbon dioxide concentration sensor 17 at a stable flow rate and then is discharged into an exhaust gas treatment pool 18;
the pressure reducing and stabilizing valve can make the temperature and pressure of gas be constant, the needle valve can make gas pass through the pipeline at stable flow rate, when the gas is discharged, the sensor can collect the related data of instantaneous gas at the frequency of once per second, and when the waste liquor is discharged, it can utilize H to make the waste liquor pass through the pipeline2O2-B1 hydrogen peroxide sensor detects the concentration of hydrogen peroxide remaining in solution; substituting the correlation data into the formula will eventually yield the value of COD, where M12.3807mg, M2Is 0.0974mg、M30.0194 mg; meanwhile, the same samples detected by a national standard method are used as a reference, the results are shown in table 1, the deviation of the COD value of the sewage at the water inlet of a certain sewage treatment plant detected by the method and the traditional method is 3.33%, and the method is proved to have better accuracy.
Example 2: the ultraviolet/H-based2O2The method for technically detecting the COD of the sewage at the water outlet of a certain sewage treatment plant comprises the following steps:
the device structure used in this example is the same as that of example 1; the difference lies in that the detection equipment on the pipeline is respectively connected with the conventional PLC module, and the automatic detection and the automatic data acquisition are realized according to the conventional mode.
Collecting sewage at a water outlet of a sewage treatment plant, pouring the sewage into a water sample storage tank 3 to be detected, filling hydrogen peroxide liquid with the concentration of 50mmol/L into a hydrogen peroxide solution storage tank 2 and ensuring that enough hydrogen peroxide solution is used for digestion; under the light of 254nm ultraviolet light, 20mL of water sample solution is pumped into a reaction tube 8 of quartz glass by an injection pump; setting a hydrogen peroxide solution to be introduced into the reaction tube at a constant flow rate of 0.05mL/min, if carbon dioxide is not obviously reduced after 8min, changing the hydrogen peroxide solution to be introduced into the reaction tube at a constant flow rate of 0.1mL/min, stopping introducing the hydrogen peroxide when the generation amount of the carbon dioxide is obviously reduced, and waiting for the water sample to be completely digested;
H2O2hydroxyl radicals (OH) with strong oxidizing property are generated under UV radiation, organic matters in the coking wastewater are oxidized and decomposed into carbon dioxide by the hydroxyl radicals, the generated carbon dioxide is discharged from one end of the quartz glass reaction tube, moisture in the gas is removed by a gas drying and condensing device, and the gas can have stable pressure through subsequent equipment by a pressure reducing and stabilizing valve 11 and a needle valve 12. Then, the gas passes through a needle valve to ensure that the gas passes through an FS4001 gas flow sensor 13, a YB-131 pressure sensor 14, a DS18b20 temperature sensor 15, an oxygen sensor 16 and a T6615-50KF carbon dioxide concentration sensor 17 at a stable flow rate and then is discharged into an exhaust gas treatment pool 18;
the pressure reducing and stabilizing valve can make the temperature and pressure of gas be constant, the needle valve can make gas pass through the pipeline at stable flow rate, when the gas is discharged, the sensor can collect the related data of instantaneous gas at the frequency of once per second, and when the waste liquor is discharged, it can utilize H to make the waste liquor pass through the pipeline2O2-B1 hydrogen peroxide sensor detects the concentration of hydrogen peroxide remaining in solution; substituting the correlation data into the formula will finally obtain the value of COD, M10.5071mg, M20.2544mg, M30.0508 mg; meanwhile, the same samples detected by a national standard method are used as a reference, the results are shown in table 1, the deviation of the COD value of the sewage at the water inlet of a certain sewage treatment plant detected by the method and the traditional method is 4.45%, and the method is proved to have better accuracy.
Example 3: the ultraviolet/H-based2O2The method for technically detecting the COD of the water in a certain lake comprises the following steps:
the device and the method used in the embodiment are the same as those in the embodiment 1, and the deviation of the COD value of the lake water detected by the method and the COD value detected by the traditional method is 5.97 percent, so that the method is proved to have better accuracy;
TABLE 1CODUV//H2O2Method and detection result of national standard method
| Water sample | UV/H2O2(mg/L) | National standard method (mg/L) | Error (%) |
| Sewage from water inlet of sewage treatment plant | 321.9 | 311.5 | 3.33 |
| Sewage from water outlet of sewage treatment plant | 30.5 | 29.2 | 4.45 |
| Water of a certain lake | 21.3 | 20.1 | 5.97 |
Claims (6)
1. Based on UV/H2O2The method for technically detecting the COD of the water quality is characterized by comprising the following steps of:
(1) introducing a water sample to be detected and hydrogen peroxide liquid with the concentration of 50mmol/L into a reaction tube under the irradiation of a 254nm ultraviolet lamp, digesting the water sample in the reaction tube, increasing the pressure value in the reaction tube by using gas generated in the digestion reaction process, discharging the generated gas from an exhaust pipe at the other end of the reaction tube, condensing and drying, continuously detecting the concentration, the gas flow, the temperature, the pressure and the oxygen concentration of carbon dioxide generated in the reaction process, discharging the gas into a tail gas treatment pool, finishing the reaction when the carbon dioxide is not detected in the gas, and determining the hydrogen peroxide content in the digested solution;
(2) calculation of COD
The total amount of hydrogen peroxide added to the reaction tube is M1The residual amount of hydrogen peroxide in the solution after digestion is M2During the reaction, part of the hydrogen peroxide is converted into oxygen, and the amount of the partially converted hydrogen peroxide is M3；
The calculation formula of COD is as follows:
wherein 3.043 is the oxygen reduction coefficient.
2. UV/H-based according to claim 12O2The method for technically detecting the COD of the water quality is characterized by comprising the following steps:
3. UV/H-based according to claim 12O2The method for technically detecting the COD of the water quality is characterized by comprising the following steps:
4. UV/H-based according to claim 32O2The method for technically detecting the COD of the water quality is characterized by comprising the following steps: the instantaneous oxygen concentration in ppm is converted to mg/L, the conversion formula is:
wherein M is the molar quantity of oxygen, and 22.4 is an ideal gas volume constant; 1000 is the ratio of mg/m3Conversion to a factor of mg/L; 273.15 is the Kelvin temperature under standard conditions, K; 101.325 is the pressure under standard conditions, KPa; t is the detected temperature, DEG C; p is the detected pressure, KPa;C 1is the instantaneous oxygen concentration, ppm.
5. Completion of the UV/H-based of any of claims 1-42O2The device for the technical detection of the COD of the water quality is characterized in that: the device comprises a deionized water storage tank (1), a hydrogen peroxide solution storage tank (2), a water sample storage tank (3) to be detected, a three-way electromagnetic valve I (4), a three-way electromagnetic valve II (5), an injection pump (6), a constant flow pump (7), a reaction tube (8), an ultraviolet lamp (9), a drying and condensing device (10), a pressure reducing and stabilizing valve (11), a needle valve (12), a gas flow sensor (13), a pressure sensor (14), a temperature sensor (15), an oxygen sensor (16), a carbon dioxide concentration sensor (17), an electromagnetic valve (19) and a waste liquid treatment pool (21), wherein the ultraviolet lamp (9) is arranged around the outer side of the reaction tube (8), the deionized water storage tank (1), the hydrogen peroxide solution storage tank (2) is communicated with the constant flow pump (7) through the three-way electromagnetic valve I (4), a pipeline, the deionized water storage tank (1) and the water sample storage tank (3) to be detected are communicated, The pipeline is communicated with an injection pump (6), the injection pump (6), a constant flow pump (7) is respectively communicated with a liquid inlet I on one end of a reaction tube (8), a liquid inlet II, a gas outlet on the other end of the reaction tube (8) is connected with a drying condensing device (10), the drying condensing device (10) is communicated with a tail gas treatment pool (18) through the pipeline, and a pressure reduction and pressure stabilization valve (11), a needle valve (12), a gas flow sensor (13), a pressure sensor (14), a temperature sensor (15), an oxygen sensor (16) and a carbon dioxide concentration sensor (17) are sequentially arranged on the pipeline, a liquid outlet on the other end of the reaction tube (8) passes through an electromagnetic valve (19), the pipeline is connected with a waste liquid treatment pool (21), and a hydrogen peroxide sensor (20) is.
6. The apparatus of claim 5, wherein: the reaction tube (8) is a quartz glass reactor.
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| CN113984855B (en) * | 2021-10-22 | 2024-01-23 | 福建福清核电有限公司 | Method and device for measuring concentration of target gas in radioactive waste gas |
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