CN110174398A - Water body total chrome content on-line measuring device and method based on high-level oxidation technology - Google Patents

Abstract

The invention discloses a kind of water body total chrome content on-line measuring device and method based on high-level oxidation technology.The present invention is dissolved in the ozone gas of high concentration in water sample more to be measured using electrolysis type ozone generator and quartz glass bubbler formula reactor；The present invention generates rapidly the hydroxyl radical free radical OH of strong oxidizing property using uv induction ozone in water, and under normal temperature conditions in the short time complete oxidation different valence state and form chromium, reduce the use of chemical reagent in oxidation process and the generation of secondary pollution；The present invention solves the problems, such as to be difficult to remove excessive oxidant in National Standard Method, and by the pH of adjusting sample, the hydrogen peroxide for avoiding ozone from generating promotes the reduction of hexavalent chromium in acid condition, improves the accuracy of water body total chrome content measurement.

Description

On-line detection device and method for total chromium content in water based on advanced oxidation technology

technical field

The invention relates to the technical field of water quality monitoring, in particular to an on-line detection device and method for total chromium content in water based on advanced oxidation technology.

Background technique

Total chromium refers to the total content of various valence and form chromium concentrations in 1L of water, and is one of the important indicators to measure water quality. Chromium is a highly toxic heavy metal that easily enters human cells, causing damage to internal organs such as liver and kidneys and DNA. Accumulation in the human body is carcinogenic and may induce gene mutation. With the development of economy, especially the development of electroplating, tanning and textile industries, a large amount of industrial wastewater containing chromium has been produced, causing serious environmental pollution. Therefore, the online detection of total chromium content in water is of great practical significance.

For the detection methods of total chromium content in water, according to the different detection principles, it can be mainly divided into diphenylcarbazide spectrophotometry, ferrous ammonium sulfate titration and flame atomic absorption spectrophotometry. At present, the online automatic monitoring instrument for total chromium water quality commonly used in the market is mainly based on diphenylcarbazide spectrophotometry, that is, in an acidic solution medium, under a certain temperature and pressure, the chromium in different valence states and forms in the water sample is high Potassium manganate or potassium persulfate solution is oxidized to form hexavalent chromium, and the hexavalent chromium ion reacts with diphenylcarbazide to form a purple-red complex, which is measured spectrophotometrically at a wavelength of 540 nm.

Diphenylcarbazide spectrophotometry has the advantages of strong selectivity, high sensitivity, accuracy and reliability, low cost, anti-interference and strong ease of use. The total chromium on-line automatic monitoring has been widely used.

The national standard method (HJ 798-2016) uses potassium permanganate and potassium persulfate as oxidants. Excessive potassium permanganate or potassium persulfate oxidant will affect color development during the detection process. Sodium nitrite is added dropwise under the shield of urea to reduce, and excess potassium persulfate needs to be removed by heating under high temperature conditions, which leads to cumbersome operation process, and when the water sample to be tested contains a large amount of organic matter, it needs to be pre-digested to eliminate organic matter. The influence on the absorbance, resulting in further lengthening of the detection period. Therefore, the national standard method for the determination of total chromium content in water has problems and shortcomings such as high reaction temperature, long pre-digestion and oxidation reaction time, many chemical reagents, high operation and maintenance costs, and complicated operation.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the deficiencies existing in the prior art, provide a water body total chromium content detection device and method based on advanced oxidation technology, adopt electrolytic ozone generator and quartz bubbling reactor to make high-concentration ozone gas It is more fully and uniformly dissolved in the water sample to be tested; UV-induced ozone is used to rapidly generate strongly oxidizing hydroxyl radicals OH in water, and completely oxidize chromium of different valences and forms in a short time at room temperature, reducing the The use of chemical reagents and the generation of secondary pollution in the oxidation process.

Another object of the present invention is to solve the problem that it is difficult to remove excess oxidant in the national standard method, and at the same time, by adjusting the pH of the sample, the hydrogen peroxide generated by ozone can be prevented from promoting the reduction of hexavalent chromium ions under acidic conditions, and the total chromium in the water can be improved. The accuracy of the assay.

According to the technical solution provided by the present invention, an on-line detection device for total chromium content in water based on advanced oxidation technology includes a quartz bubbling reactor, and a first ultraviolet lamp and a second ultraviolet lamp are respectively suspended on both sides of the outside of the quartz bubbling reactor. Two ultraviolet lamps; a water sample inlet and a buffer inlet are arranged on both sides of the upper part of the quartz bubble reactor; the water sample inlet is connected to a water sample storage tank, and a first water sample storage tank is provided at the outlet end Syringe pump; the buffer inlet is connected to the buffer tank, and a second syringe pump is arranged at the outlet end of the buffer tank; an ozone gas bubbling tube and tail gas outlet; one end of the ozone gas bubbling tube extends into the inside of the quartz bubbling reactor as the outlet of the ozone gas bubbling tube, and the other end of the ozone gas bubbling tube remains in the The outside of the quartz bubbling reactor is used as the inlet of the ozone gas bubbling tube, the inlet of the ozone gas bubbling tube is connected with the electrolytic ozone generator, and a first gas output end of the electrolytic ozone generator is provided. A solenoid valve; a discharge port is provided at the bottom of the quartz bubble reactor, the discharge port is connected to the first inlet end of the color developing cell through a pipeline, and is provided at the outlet end of the quartz bubble reactor the second solenoid valve; the second inlet end of the color developing tank is connected with the acid mixing tank, and a third syringe pump is arranged at the outlet end of the acid mixing tank; the third inlet end of the color developing tank is connected with the total chromium color developing agent tank, A fifth syringe pump is arranged at the outlet end of the total chromium developer tank; the first outlet end of the color developing cell is connected to the spectrophotometer, and a fourth syringe pump is arranged at the first outlet end of the color developing cell; The second outlet end of the color developing cell is connected to the waste liquid tank, and a third solenoid valve is arranged at the second outlet end of the color developing cell.

The electrolytic ozone generator uses a solid polymer electrolyte membrane (PEM) type ozone generating module to generate high-concentration ozone gas with a mass concentration of 18-20 wt% by electrolyzing distilled water, and there are four PEM ozone generating modules.

The mass concentration range of total chromium in the water sample to be tested in the water sample storage tank is 0-1 mg/L.

The quartz bubbling reactor is cylindrical, made of quartz glass, and has dimensions of 140-160 mm in height, 15-25 mm in inner diameter, and 18-28 mm in outer diameter. Most preferably, the quartz bubbling reactor is cylindrical, made of quartz glass, and the dimensions are: height 150 mm, inner diameter 20 mm, and outer diameter 23 mm.

The ozone gas bubbling tube is made of quartz, the inner diameter is 1.5-2.5 mm, and the outer diameter is 3-5 mm, and the distance between the outlet of the ozone gas bubbling tube and the bottom of the quartz bubbling reactor is 15-25 mm. Most preferably, the ozone gas bubbling tube is also made of quartz, the inner diameter is 2 mm, the outer diameter is 4 mm, and the distance between the outlet of the ozone gas bubbling tube and the bottom of the quartz bubbling reactor is 20 mm.

The power of the first ultraviolet lamp and the second ultraviolet lamp is 12-24 W, and the wavelength of the ultraviolet light irradiated is 254 nm. Most preferably, the power of the first ultraviolet lamp and the second ultraviolet lamp is 18W, and the wavelength of the irradiated ultraviolet light is 254nm.

The buffer solution in the buffer tank is a buffer solution of borax-sodium hydroxide, the pH is about 12, and the pH is 11.5-12.5.

The mixed acid solution in the mixed acid tank is a mixed solution of phosphoric acid, sulfuric acid and water, wherein the volume ratio of phosphoric acid, sulfuric acid and water is 1:0.8-1.2:1.5-2.5. Most preferably, the mixed acid solution in the mixed acid tank is a mixed solution of phosphoric acid, sulfuric acid and water, wherein the volume ratio of phosphoric acid, sulfuric acid and water is 1:1:2.

The developer in the total chromium developer tank is a diphenylcarbazide-acetone solution with a mass concentration of 1.5-2.5 g/L. Most preferably, the developer in the total chromium developer tank is a diphenylcarbazide-acetone solution with a mass concentration of 2g/L.

A method for online detection of total chromium content in a water body, using an online detection device for total chromium content in a water body based on advanced oxidation technology, comprising the following steps:

(1) close the first solenoid valve, start the electrolytic ozone generator, so that enough high-concentration ozone gas is generated in the electrolytic ozone generator, and the static pressure of the water column height of 8～12cm (preferably 10cm) is generated;

(2) The first syringe pump injects 15-25mL (preferably 20mL) of the water sample to be tested from the water sample storage tank into the quartz bubble reactor, and the second syringe pump buffers 3-7mL (preferably 5mL) The solution is injected from the buffer tank to the quartz bubble reactor, so that the pH of the mixed water sample solution is greater than 11.5 and controlled between 11.5 and 12;

(3) Turn on the first ultraviolet lamp, the second ultraviolet lamp and the first solenoid valve, so that the electrolytic ozone generator generates high-concentration ozone gas with a static pressure of 8-12cm (preferably 10cm) water column height through the first solenoid valve and ozone The gas bubbling tube enters the quartz bubbling reactor by bubbling, and the first ultraviolet lamp and the second ultraviolet lamp are arranged on both sides of the quartz bubbling reactor to emit 254nm ultraviolet light, and the ozone gas is in the 254nm ultraviolet light. Under irradiation, it reacts rapidly with the water sample to produce strong oxidizing hydroxyl radical OH, thereby oxidizing the different valence states and forms of chromium in the water sample to be tested (0-1mg/L) to hexavalent chromium, and the oxidative digestion reaction time is 3 ~7min (preferably 5min);

(4) after the oxidative digestion reaction finishes, open the second solenoid valve, and discharge the water sample to be tested after the reaction is completed into the color developing tank;

(5) After the water sample is completely discharged into the color developing tank, the third syringe pump will transfer 0.5-1.0 mL (preferably 0.7 mL) of mixed acid solution (the volume ratio of phosphoric acid, sulfuric acid and water is 1:1:2) from the mixed acid The tank is injected into the color developing tank, and 0.5-1.5 mL (preferably 1 mL) diphenylcarbazide-acetone solution is injected from the total chromium color developing agent tank into the color developing tank by the fifth syringe pump, and the color developing reaction 3 ~8min (preferably 5min);

(6) After the color reaction is completed, inject 3-8 mL (preferably 5 mL) of the color-developed solution from the color-developing tank into the spectrophotometer by the fourth syringe pump; discharge the remaining color-developed solution into the waste liquid tank In; the spectrophotometer measures the absorbance value of the solution at 540nm wavelength after color development, and calculates the total chromium content.

Compared with the prior art, the present invention has the following advantages:

Compared with the potassium permanganate and potassium persulfate used in the national standard method, the present invention has the following advantages: the reaction temperature of oxidative digestion is low, and the reaction can be rapidly reacted at room temperature under ultraviolet induction; the oxidative digestion time is short, and 1 mg/L can be completely oxidized in 5 minutes Ozone is used as the initiator of hydroxyl radicals, and excess ozone does not need tail treatment, which reduces the use of chemical reagents; the generated ozone gas can be decomposed into oxygen by itself, with less secondary pollution.

The invention simultaneously adjusts the pH of the sample, prevents the hydrogen peroxide generated by ozone from promoting the reduction of hexavalent chromium ions under acidic conditions, and improves the accuracy of the determination of the total chromium content in the water body.

Description of drawings

Fig. 1 is the structural representation of the on-line detection device of total chromium content in water based on advanced oxidation technology of the present invention;

Among them, 1. Electrolytic ozone generator; 2. Water sample storage tank; 3. First syringe pump; 4. First solenoid valve; 5. First ultraviolet lamp; 6. Second solenoid valve; 7. Waste liquid tank ; 8. Ozone gas bubbling tube; 9. Quartz bubbling reactor; 10. Second ultraviolet lamp; 11. Third solenoid valve; 12. Exhaust gas outlet; 13. Second syringe pump; 14. Buffer tank ; 15. Mixing acid tank; 16. The third syringe pump; 17. The fourth syringe pump;

Fig. 2 is the fitting curve diagram of the online detection method of total chromium content in water of the present invention.

Detailed ways

As shown in Figure 1, it is an on-line detection device for total chromium content in water based on advanced oxidation technology of the present invention, comprising a quartz bubble reactor 9, and a first ultraviolet lamp 5 is respectively suspended on both sides of the outer quartz bubble reactor 9. and the second ultraviolet lamp 10; a water sample inlet and a buffer inlet are provided on both sides of the upper part of the quartz bubble reactor 9; the water sample inlet is connected with the water sample storage tank 2, and the first Syringe pump 3; the buffer inlet is connected to the buffer tank 14, and the second syringe pump 13 is arranged at the outlet end of the buffer tank 14; the inlet of the ozone gas bubbling tube 8 and the exhaust gas outlet are arranged at the upper end of the quartz bubbling reactor 9 12; Connect with the electrolysis ozone generator 1 at the inlet of the ozone gas bubbling tube 8, and set the first solenoid valve 4 at the gas output end of the electrolysis ozone generator 1; The outlet, the outlet is connected with the first inlet end of the color developing tank 18 through the pipeline, and the second solenoid valve 6 is set at the outlet end of the quartz bubble reactor 9; connection, a third syringe pump 16 is arranged at the outlet end of the acid mixing tank 15; the third inlet end of the color developing tank 18 is connected with the total chromium developer tank 19, and the fifth syringe pump 20 is provided at the outlet end of the total chromium developer tank 19; The first outlet end of the color developing cell 18 is connected to the spectrophotometer 21, and a fourth syringe pump 17 is arranged at the first outlet end of the color developing cell 18; the second outlet end of the color developing cell 18 is connected to the waste liquid tank 7, and A third solenoid valve 11 is provided at the second outlet end of the color developing cell 18 .

The electrolytic ozone generator 1 uses electrolytic distilled water to generate ozone gas with a mass concentration of 18-20%.

The quartz bubbling reactor 9 is cylindrical, made of quartz glass, and its dimensions are: height 150mm, inner diameter 20mm, outer diameter 23mm, and the ozone gas bubbling tube 8 is also made of quartz, with an inner diameter of 2mm and an outer diameter of 4mm. The distance between the outlet of the gas bubble tube 8 and the bottom of the quartz bubble reactor 9 is 20 mm.

The power of the first ultraviolet lamp 5 and the second ultraviolet lamp 10 is 18W, and the wavelength of the irradiated ultraviolet light is 254 nm.

The buffer solution in the buffer tank 14 is a mixed solution of borax-sodium hydroxide, and its pH is about 12.

The mixed acid tank 15 is a mixed solution of phosphoric acid, sulfuric acid and water, wherein the volume ratio of phosphoric acid, sulfuric acid and water is 1:1:2.

The total chromium developer tank 19 is a diphenylcarbazide-acetone solution with a concentration of 2 g/L.

The spectrophotometer 21 only outputs the absorbance value at the wavelength of 540 nm.

Adopt the on-line detection device of total chromium content of water body based on advanced oxidation technology of the present invention to detect the total chromium content of water body according to the following steps:

(1) close the first solenoid valve 4, start the electrolytic ozone generator 1, make enough high-concentration ozone gas in the electrolytic ozone generator 1, and generate the static pressure of about 10cm water column height;

(2) The first syringe pump 3 injects 20 mL of the water sample to be tested from the water sample storage tank 2 into the quartz bubbling reactor 9, and the second syringe pump 13 injects 5 mL of buffer solution from the buffer tank 14 into the quartz drum Bubble reactor 9, so that the pH of the mixed water sample solution is greater than 11.5;

(3) Turn on the first ultraviolet lamp 5, the second ultraviolet lamp 10 and the first solenoid valve 4, so that the electrolytic ozone generator 1 generates the high-concentration ozone gas of 10cm water column height static pressure through the first solenoid valve 4 and the ozone gas drum The bubble tube 8 enters the quartz bubble reactor 9 by bubbling, and the first ultraviolet lamp 5 and the second ultraviolet lamp 10 are arranged on both sides of the quartz bubble reactor 9 to emit 254nm ultraviolet light, and the ozone gas is at 254nm. Under the irradiation of ultraviolet light, it reacts rapidly with the water sample to generate strong oxidizing hydroxyl radical OH, thereby oxidizing the different valence and forms of chromium in the water sample to be tested (0-1mg/L) to hexavalent chromium, and the oxidation digestion reaction The time is 5min;

(4) after the oxidative digestion reaction finishes, open the second solenoid valve 6, and discharge the water sample to be measured after the reaction is completed into the color developing cell 18;

(5) After the water sample is completely discharged into the color developing tank 18, the third syringe pump 16 injects 0.7 mL of mixed acid solution (the volume ratio of phosphoric acid, sulfuric acid and water is 1:1:2) from the mixed acid tank 15 to the color developing In the pool 18, the fifth syringe pump 20 injects 1mL of diphenylcarbazide-acetone solution from the total chromium developer tank 19 into the color developing pool 18, and the color reaction is performed for 5min;

(6) After the color reaction is completed, the fourth syringe pump 17 injects 5mL of the color-developed solution from the color-developing tank 18 into the spectrophotometer 21; the remaining color-developed solution is discharged into the waste liquid tank 7; Spectroscopy The photometer 21 measures the absorbance value of the color-developed solution at a wavelength of 540 nm, and calculates the total chromium content.

The present invention adopts the diphenylcarbazide spectrophotometry based on advanced oxidation technology, which rapidly generates strong oxidizing hydroxyl radical·OH under the condition of alkaline solution by ozone ultraviolet light to oxidize chromium in different valence states and forms to six For valent chromium, the pH of the solution is adjusted to acidity by mixing acid, and the hexavalent chromium ion reacts with diphenylcarbazide to form a purple-red complex, which is measured spectrophotometrically at a wavelength of 540 nm.

The theoretical basis for the quantitative determination of total chromium water quality by diphenylcarbazide spectrophotometry is the Lambert-Beer law. The Lambert-Beer law is expressed by equation (1) as:

A=KCL (1)

In formula (1), A is the absorbance value; K is the absorbance coefficient, the unit is L·mg/mm, which is related to the wavelength of the incident light and the properties of the light-absorbing substance; C is the concentration of the light-absorbing substance, the unit is mg/L; L is the thickness of the absorbing liquid layer, in mm. Then use the absorbance value A corresponding to the standard hexavalent chromium concentration C to find the relationship between the absorbance and the hexavalent chromium concentration, and fit the relationship curve between the hexavalent chromium concentration and the absorbance. Finally, it can be calculated according to the curve equation. The hexavalent chromium concentration of the water sample to be tested. The blank experiment results are shown in Table 1.

Table 1 Blank test result table

Among them, according to the requirements of HJ168, the detection limit of this detection method is calculated as follows:

MDL=t _(n-1,0.99) ×S (2)

In formula (2), MDL is the detection limit of the method; S is the standard deviation of the multiple measured values of the blank sample; t is the t distribution with the degree of freedom n-1 and the confidence level is 99%; n is the number of parallel determinations of the sample . Therefore, according to the data obtained in Table 1, the method detection limit MDL=2.355×0.0003≈7×10 ^-4 mg/L.

Prepare standard solutions of 0.04, 0.08, 0.12, 0.16, 0.20, 0.40, 0.60, 0.80 and 1.00 mg/L of hexavalent chromium, carry out three parallel experiments on each standard of hexavalent chromium, and obtain the absorbance of standard samples with different concentrations The average value, and the experimental results of standard samples are shown in Table 2.

Table 2 Standard sample test result table

Hexavalent chromium standard (mg/L) Absorbance average 0.04 0.0284 0.08 0.0589 0.12 0.0882 0.16 0.1180 0.20 0.1483 0.40 0.2913 0.60 0.4484 0.80 0.6050 1.00 0.7564

The experimental data were linearly fitted on Origin software, and the fitting curve was shown in Figure 2.

According to the linear fitting results, the relationship between the hexavalent chromium concentration C and the absorbance value A in the concentration range of 0 to 1 mg/L can be expressed by formula (3):

A=0.75661C-0.00292(R _f =0.9998) (3)

It can be seen from the correlation coefficient R _f of formula (3) that in the whole measurement range, the concentration of hexavalent chromium has a good linear relationship with the absorbance value.

Further prepare 0.2mg/L and 0.8mg/L trivalent chromium standard solutions, carry out 6 groups of parallel experiments on trivalent chromium standard samples with different concentrations, and then enter the final absorbance value of the standard sample into formula (3) to calculate the measured total chromium concentration . Finally, the precision and indication error of the data are calculated according to the performance indicators of the total chromium water quality automatic online monitor. The final results are shown in Table 3.

Table 3 Standard sample test result table

It can be seen from Table (3) that the precision and indication error of the diphenylcarbodihydrazide spectrophotometry based on advanced oxidation technology within the range are 1.16% and 2.50%, respectively, which are in line with the performance of the total chromium water quality automatic online monitor. Index requirements: precision ≤ 5% and indication error within ± 5%.

Claims (10)

1. a kind of water body total chrome content on-line measuring device based on high-level oxidation technology, including quartzy bubbling style reactor (9), The first ultraviolet lamp (5) and the second ultraviolet lamp (10) are hung respectively in the both sides external of quartzy bubbling style reactor (9)；In the stone The top two sides setting water sample import of English bubbling style reactor (9) and buffer inlet；The water sample import and water sample storage tank (2) The first syringe pump (3) are arranged in water sample storage tank (2) outlet end in connection；The buffer inlet and buffering flow container (14) are even It connects, the second syringe pump (13) is set in the buffering flow container (14) outlet end；In the upper end of the quartzy bubbling style reactor (9) Ozone gas bubbling pipe (8) and tail gas outlet (12) are set；One end of the ozone gas bubbling pipe (8) extend into described It is exported inside quartzy bubbling style reactor (9) as the ozone gas bubbling pipe (8), the ozone gas bubbling pipe (8) The other end stay in the quartzy bubbling style reactor (9) outside as ozone gas bubbling pipe (8) import, the ozone gas (8) import of body bubbling pipe is connect with the ozone generator by electrolytic process (1), the gas in the ozone generator by electrolytic process (1) The first solenoid valve (4) are arranged in output end；It is equipped with outlet in the bottom of the quartzy bubbling style reactor (9), the outlet is logical It crosses pipeline to connect with the first input end of colour developing pond (18), in the outlet end setting second of the quartzy bubbling style reactor (9) Solenoid valve (6)；(18) second input end of colour developing pond is connect with nitration mixture tank (15), is arranged in nitration mixture tank (15) outlet end Third syringe pump (16)；Colour developing pond (18) the third input end is connect with total chromium color developing agent tank (19), is developed the color in total chromium The 5th syringe pump (20) is arranged in agent tank (19) outlet end；The first exit end of colour developing pond (18) and spectrophotometer (21) are even It connects, the 4th syringe pump (17) is set in the first exit end of colour developing pond (18)；The second outlet end of colour developing pond (18) It is connect with waste liquid tank (7), third solenoid valve (11) is set at the second outlet end of colour developing pond (18).

2. the water body total chrome content on-line measuring device based on high-level oxidation technology as described in claim 1, which is characterized in that The quartz bubbling style reactor (9) is cylinder, and material is quartz glass, size are as follows: 140~160mm of height, internal diameter 15~ 25mm, 18~28mm of outer diameter.

3. the water body total chrome content on-line measuring device based on high-level oxidation technology as described in claim 1, which is characterized in that The ozone gas bubbling pipe (8) is quartz material, and internal diameter is 1.5~2.5mm, and outer diameter is 3~5mm, the ozone gas drum Distance is 15~25mm between bubble pipe (8) outlet and quartzy bubbling style reactor (9) bottom.

4. the water body total chrome content on-line measuring device based on high-level oxidation technology as described in claim 1, which is characterized in that The watt level of first ultraviolet lamp (5) and the second ultraviolet lamp (10) is 12~24W, and the ultraviolet light wave irradiated is a length of 254nm。

5. the water body total chrome content on-line measuring device based on high-level oxidation technology as described in claim 1, which is characterized in that Buffer solution in buffering flow container (14) is borax-sodium hydroxide buffer solution.

6. the water body total chrome content on-line measuring device based on high-level oxidation technology as described in claim 1, which is characterized in that Mixed acid solution in the nitration mixture tank (15) is the mixed solution of phosphoric acid, sulfuric acid and water, wherein the volume ratio of phosphoric acid, sulfuric acid and water For 1:0.8~1.2:1.5~2.5.

7. the water body total chrome content on-line measuring device based on high-level oxidation technology as described in claim 1, which is characterized in that Color developing agent in total chromium color developing agent tank is diphenylcarbazide-acetone soln that mass concentration is 1.5~2.5g/L.

8. a kind of water body total chrome content online test method, which is characterized in that use the described in any item bases of claim 1~7 In the water body total chrome content on-line measuring device of high-level oxidation technology, comprising the following steps:

(1) the first solenoid valve is closed, electrolysis type ozone generator is started, so that generating enough height in electrolysis type ozone generator Concentration of ozone gas, and it is produced as the static pressure of 8~12cm water-column；

(2) 15~25mL water sample to be measured is injected into quartzy bubbling style reactor from water sample storage tank by the first syringe pump, by second 3~7mL buffer solution is injected into quartzy bubbling style reactor from buffer tank by syringe pump, so that mixed sample pH value of solution is greater than 11.5；

(3) the first ultraviolet lamp, the second ultraviolet lamp and the first solenoid valve are opened, so that electrolysis type ozone generator generates 8~12cm The high-concentrated ozone gas of water-column static pressure is entered in a manner of being bubbled the first solenoid valve and ozone gas bubbling pipe In quartzy bubbling style reactor, the first ultraviolet lamp is set in the two sides of quartzy bubbling style reactor and the second ultraviolet lamp issues 254nm ultraviolet light, ozone gas react the hydroxyl for generating strong oxidizing property under the irradiation of 254nm ultraviolet light with water sample oxidation resolution Free radical OH；

(4) oxidation resolution after reaction, opens second solenoid valve, and the water sample to be measured after reaction is completed is discharged into colour developing pond In；

(5) after water sample is discharged into colour developing pond completely, 0.5~1.0mL mixed acid solution is injected into from nitration mixture tank by third syringe pump It develops the color in pond, is injected into 0.5~1.5mL diphenylcarbazide-acetone soln from total chromium color developing agent tank by the 5th syringe pump aobvious In color pond, 3~8min of chromogenic reaction；

(6) after to chromogenic reaction, solution after 3~8mL colour developing is injected into spectrophotometric from colour developing pond by the 4th syringe pump Meter；Solution after remaining colour developing is discharged into waste liquid tank；Spectrophotometer tests suction of the solution at 540nm wavelength after the colour developing Total chrome content is calculated in shading value.

9. water body total chrome content online test method as claimed in claim 8, which is characterized in that in step (2), so that mixing Water sample pH value of solution is greater than 11.5, controls between 11.5~12.

10. water body total chrome content online test method as claimed in claim 8, which is characterized in that described in step (3) The oxidation resolution reaction time is 3~7min.