KR101522527B1 - Method for Analyzing Copper Concentration in Water - Google Patents

Abstract

The present invention relates to a method for analyzing the concentration of contaminants in wastewater containing a high concentration of contaminants, and more particularly, to a method for analyzing copper concentration in water.
According to the present invention, it is possible to reduce the amount of analytes, diluents, and analytical reagents to be used, thereby simplifying the injection and mixing of analytes, diluents, and analytical reagents.

Description

Method for Analyzing Copper Concentration in Water [

The present invention relates to a method for analyzing the concentration of contaminants in wastewater containing a high concentration of contaminants, and more particularly, to a method for analyzing copper concentration in water.

Among the methods for measuring the contamination concentration of a specific substance in wastewater, there is a colorimetric method. Analytical reagents and automatic analyzers are needed to measure the contamination concentration of specific substances in wastewater using colorimetric methods. The analytical reagent reacts with a specific substance in the sample to give it a unique color. The automatic analyzer consists of sample, dilution water and dosing device of analytical reagent, mixing device, optical system, microprocessor, monitor and so on. The optical system consists of a light source and a detector tube for quantifying the intensity of color by measuring the transmittance by irradiating the developed sample with light. When the color intensity is quantified, it can be converted into a concentration using a known calibration curve.

In order to perform automatic analysis using the colorimetric method, the amount of the sample should be automatically and precisely metered. Mixing of analytical reagent and sample should be uniform.

On the other hand, in the colorimetric method, the measurement concentration range is limited due to the limitation of the measurement reagent and the permeability. Especially in the case of high concentration samples, it is often out of the measurement concentration range. Therefore, precise dilution is necessary to analyze such a high concentration sample, and dilution of the sample should be automatically and precisely performed for automatic analysis.

As described above, samples, dilution water, and analytical reagents should be weighed to dilute or inject analytical reagents. In general, the sample, dilution water and analytical reagent are metered using a syringe pump or a measuring cup. However, the syringe pump is very expensive and difficult to maintain. In the case of using a measuring cup, there is no problem when the amount of the sample is large, but there is a disadvantage in that the amount of the sample is not constant when the amount of the sample is small. If the amount of the sample is large, diluted water and analytical reagent are consumed, and the mechanical device is also difficult to be large. Especially, analytical reagent is added in small amount compared with sample, so it is difficult to use measuring cup.

When the sample is diluted or the reagent is added to the sample, it should be uniformly mixed. It is common to use a magnetic stirrer for such mixing. However, if a mixing tank equipped with a magnetic stirrer is constituted, the apparatus becomes complicated and takes up a large volume in the automatic analyzer. In addition, it is troublesome to clean the magnetic stirrer contained in the dilution reaction tank from time to time. In a mixing method, a sample, diluted water and a reagent are added to a mixing tank in a predetermined amount, and air is injected and mixed. In this method, air bubbles are often generated in the mixed solution when the air injection amount and time are long. When bubbles are generated, they cause errors in analysis at later stages.

The present invention provides a method for analyzing the copper concentration of water capable of simultaneously injecting a sample, a diluent, and an analysis reagent.

Accordingly, the present invention provides an analysis target sample water tank containing a sample to be analyzed; A diluent bath containing a diluent; An analytical reagent bath containing analytical reagent containing carbon disulfide and diethanolamine; A mixing tube in which a spiral groove is formed on the inner surface so that the sample to be analyzed, the diluting solution, and the analysis reagent are respectively injected from the sample water to be analyzed, the diluting water tank, and the analysis reagent water tank; A degassing vessel for introducing the mixed liquor mixed in the mixing tube to remove bubbles contained in the mixed liquor; And an optical system for measuring the concentration of copper from the mixed liquid in which the bubbles have been removed from the degassing vessel, wherein (S1) the analysis including the sample to be analyzed, the diluent and the carbon disulfide and the diethanolamine Injecting reagents into a mixing tube having a helical groove formed on its inner surface for the same time, and mixing the reagents; (S2) injecting air into the mixing tube; (S3) transferring the mixed liquid discharged from the mixing tube to the degassing vessel after the air is injected in the step (S2), thereby removing bubbles of the mixed liquid; And (S4) measuring the concentration of copper from the mixed solution from which bubbles have been removed from the degassing vessel.

The copper concentration analyzing method according to the present invention is characterized in that air is injected into the degassing vessel in the step (S3).

In the present invention, the mixing tube of the copper concentration analyzer is a cylindrical shape having a diameter of 1 to 3 mm, the spiral groove has a depth of 0.5 to 2 mm, a distance between spiral lines of 0.5 to 1.4 cm, , The dilution solution induction tube and the analysis reagent induction tube are connected to the sample induction tube, the dilution solution inducing tube and the analyte reagent induction tube for inducing the injection of the sample to be analyzed, the diluting solution and the analysis reagent, and the inner diameters of the sample induction tube, A peristaltic pump is disposed between the mixing tube and the sample water tank for the analysis, the diluting water tank, and the analysis reagent water tank, respectively, and the peristaltic pump has a rotation speed of the driving motor 20 to 250 rpm, and the peristaltic pump is connected to a mixing tube, a sample water sample to be analyzed, a diluent water tank, and an analysis reagent water tank by tubes each having an inner diameter of 0.5 to 6 mm.

According to the present invention, it is possible to reduce the amount of analytes, diluents, and analytical reagents to be used, thereby simplifying the injection and mixing of analytes, diluents, and analytical reagents.

In addition, the amount of waste liquid generated after the water quality analysis can be reduced, which is environmentally friendly.

1 is a flow chart of a method for analyzing the copper concentration of water using the copper concentration analyzing apparatus according to the present invention.
2 shows a mixing tube included in the copper concentration analyzing apparatus according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 is a flow chart of a method for analyzing the copper concentration of water using the copper concentration analyzing apparatus according to the present invention.

The method for analyzing the copper concentration of water according to the present invention comprises the steps of: (S1) subjecting a sample to be analyzed, a diluent, and an analytical reagent containing carbon disulfide and diethanolamine to a mixing tube having a spiral groove formed on its inner surface for the same time ; (S2) injecting air into the mixing tube; (S3) transferring the mixed liquid discharged from the mixing tube to the degassing vessel after the air is injected in the step (S2), thereby removing bubbles of the mixed liquid; And (S4) measuring the concentration of copper from the mixed solution from which bubbles have been removed from the degassing vessel.

In order to perform the copper concentration analysis, the present invention includes a sample tank 100 to be analyzed, which contains a sample to be analyzed; A diluting liquid tank 200 containing a diluting liquid; An analytical reagent water tank 300 containing analytical reagent containing carbon disulfide and diethanolamine; A mixing tube 5 having a spiral groove formed on its inner surface so that the sample, the diluent, and the analyzing reagent are injected from the sample water tank, the diluting water tank, and the analyte tank, respectively; A degassing vessel (6) for removing the bubbles contained in the mixed solution by flowing the mixed solution mixed in the mixing tube; And an optical system for measuring the concentration of copper from the mixed solution in which air bubbles have been removed from the degassing vessel.

The copper concentration analyzing method of water quality according to the present invention is characterized in that the injection and mixing of the sample can be performed by a single process in one apparatus.

The sample water tank 100 to be analyzed is a water tank containing a predetermined amount of sample to be analyzed to inject the sample to be analyzed into the mixing tube 5.

The diluting liquid tank 200 is a water tank containing a predetermined amount of diluting liquid for injecting the diluting liquid into the mixing tube 5. [

The analysis reagent water tank 300 is a water tank containing a predetermined amount of analysis reagent for injecting the analysis reagent into the mixing pipe 5.

The sample water tank 100 to be analyzed, the diluent water tank 200 and the analytical reagent water tank 300 are respectively connected to the mixing pipe 5 by tubes and the analytical sample water tank 100, the diluent water tank 200, A peristaltic pump is disposed between the reagent tank 300 and the mixing tube 5, and the peristaltic pump injects the sample, the diluent, and the analysis reagent into the mixing tube 5, respectively.

2 shows a mixing tube included in the copper concentration analyzing apparatus according to the present invention.

On the side of the mixing tube, a reagent induction pipe 12 to be analyzed, to which the sample to be analyzed is injected from the sample water tank 100 to be analyzed, a diluting liquid guide tube 13 into which the diluent is injected from the diluent water tank 200, 300 is formed with an analytical reagent induction tube 14 into which an analytical reagent is injected. The ends of the analysis target reagent induction pipe 12, dilution liquid induction pipe 13 and analytical reagent induction pipe 14 are connected to the sample water tank 100 to be analyzed, the diluent water tank 200 and the analysis reagent water tank 300, respectively The tube connector is fastened so that the means is connected to the end of the tube.

In addition, a spiral groove is formed in the inner surface of the mixing tube, and the analyte, the diluent and the analyzing reagent are injected into the mixing tube by the spiral groove and mixed with each other, so that the analyte, diluent, A mixed solution is produced, so that the mixing efficiency can be improved.

The mixing tube is a cylindrical shape having a diameter of 1 to 3 mm, and the spiral groove can be formed on the inner surface of the mixing tube by making a jig. The spiral groove may be formed with a negative angle and the depth may be 0.5 to 2 mm, and the distance between the spirals (the distance between adjacent spirals) may be 0.5 to 1.4 cm, and the distance between the depth of the groove and the spiral . That is, when the distance between the depth of the groove and the spiral is less than the above-described numerical value range, the mixing effect is insignificant. When there is a groove in the mixing tube, the flow velocity of the center portion of the mixing tube is small, and the flow of the liquid at the inner surface portion of the mixing tube, which collides with the groove, is slow and the mixing is promoted.

In addition, the upper end of the mixing tube is connected to an air pump capable of injecting air into the mixing tube. After the injection of the sample to be analyzed, the diluting liquid and the analysis reagent is completed, the resulting mixed liquid is transferred to the degassing vessel, and air is injected into the mixing tube by using the air pump, To the degassing tank. The air pump may have a discharge pressure of 20 to 80 kPa. If the discharge pressure is less than 20 kPa, the mixed liquid may remain on the inner surface of the mixing pipe. If the discharge pressure is more than 80 kPa, there is no benefit of increasing the discharge pressure.

In the degassing tank, a mixture of the sample to be analyzed, diluted solution and analytical reagent is injected into the mixing tube. The deaeration tank serves to stabilize the mixed liquid while removing bubbles which may occur during the mixing process in the mixing tube. The bubbles contained in the mixed liquid can be removed by injecting air through an air supply pipe attached to the lower part of the degassing vessel using an air pump. By removing bubbles from the mixed solution, the measurement error can be reduced when measuring the transmittance in the optical system.

The air pump may be connected to the lower end of the degassing tank, and the air pump may have a discharge pressure of 15 to 60 kPa. If the discharge pressure is less than 15 kPa, the effect of removing bubbles contained in the mixed liquid is insignificant. If the discharge pressure is more than 60 kPa, there is no benefit of increasing the discharge pressure.

The optical system can quantify the intensification of color by measuring the transmittance of the mixed liquid injected from the degassing tank. The optical system is composed of a light source and a detection tube. The intensity of the color can be quantified, and then the concentration can be converted using a previously known calibration curve. However, the optical system is not limited to a commonly used optical system.

On the other hand, a peristaltic pump is placed between the mixing tube and the water tanks in order to inject the sample to be analyzed, the diluting solution and the analyzing reagent from the sample water tank, the diluting water tank and the analysis reagent water tank into the mixing tube, respectively .

At this time, the rotation speed of the peristaltic pump may be 20 to 250 rpm. If the rotation speed of the drive motor is less than 20 rpm, liquid may not be conveyed well. If the rotation speed exceeds 250 rpm, the conveyance amount is too large, which makes simultaneous injection of sample to be analyzed, diluent and analytical reagent difficult.

In addition, the peristaltic pump may be connected to the mixing tube, the sample water to be analyzed, the dilution water tank, and the analysis reagent water tank by tubes, respectively, and the tube may have an inner diameter of 0.5 to 6 mm. If the diameter of the tube is less than 0.5 mm, the tube is often clogged and is difficult to use. If the diameter of the tube is more than 6 ml, the amount of the reagent is too large to simultaneously inject the sample, the diluent and the reagent.

The copper concentration analyzing apparatus may further include a microprocessor and a monitor. At this time, the microprocessor is connected to all the pumps and valves installed in the water quality analysis apparatus, and can control the entire water quality analysis apparatus by controlling the pumps and valves.

The measured permeability through the copper concentration analyzer of water quality can be converted to a concentration in microprocessor and then displayed as a monitor.

Again, the analysis method of copper concentration of water quality is as follows.

In the step (S1), a sample to be analyzed, a diluent, and an analysis reagent containing carbon disulfide and diethanolamine are injected into a mixing tube having a helical groove formed on its inner surface for the same period of time, respectively.

 The amount of the sample to be analyzed injected into the mixer may vary depending on the sample to be analyzed. However, the diameter of the tube for injecting the sample to be analyzed, the diluting solution and the analyzing reagent into the mixing tube, The rotating speed of the driving motor of the tick pump and the diameters of the sample pipeline, dilution pipeline, and analysis reagent pipeline included in the mixing tube are adjusted to equalize the injection time of the sample to be analyzed, the diluting liquid and the analysis reagent . The larger the diameter of the tube to be attached to the peristaltic pump, the larger the diameter of the induction pipe included in the mixing tube, and the larger the motor rotation speed of the pump, the larger the amount of liquid transferred. Therefore, by adjusting these three factors, the amount of sample, diluent and analytical reagent can be adjusted, which enables simultaneous injection of three liquids. In the present invention, a low-cost general DC geared motor is used. In the case of pump motors, it is possible to adjust the rotation speed freely by using the stepping motor, so it is possible to minimize the diameter of the tube or the diameter of the guide pipe. However, for stepping motors, expensive and precise controllers have to be added, and it is also difficult to control the flow rate of the liquid only by the rotation speed of the motor. Therefore, in the present invention, a method of controlling the diameter of the tube and the diameter of the induction pipe using an inexpensive DC geared motor is devised.

(S2) is a step of injecting air into the mixing tube. By injecting air into the mixing tube, the mixed liquid, which may remain on the inner surface of the mixing tube, can be transferred to the degassing vessel.

(S3) is a step of transferring the mixed liquid discharged from the mixing tube into which the air is injected to the degassing vessel to remove air bubbles in the mixed liquid. In this way, when the air bubbles of the mixed liquid are removed, the error can be reduced when the transmittance of the optical system is measured.

The copper concentration analyzing method of the present invention is characterized in that, in the step (S3), air is injected into the degassing tank.

According to the copper concentration analyzing method of water quality according to the present invention, it is possible to simultaneously inject the sample, the diluting liquid and the analyzing reagent, so that the amount of the sample, the diluting liquid and the analyzing reagent can be reduced, which is not only economical, There is an eco-friendly effect because the amount can be reduced.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

In the following examples and comparative examples, copper standard solution is used as a sample to be analyzed, ultrapure water is used as a dilution solution, and carbon disulfide and diethanol amine mixed solution are used as assay reagents.

Example  One

Copper sulfate was dissolved in ultrapure water to prepare copper standard solutions of 2, 5, 7 and 10 ppm, respectively.

The copper concentration was measured in a copper concentration analyzer as shown in FIG. Wherein the copper concentration analyzing apparatus includes a sample tank to be analyzed and an analysis reagent water tank, a mixing tube into which analytes and analytical reagents are respectively injected from the water tanks, and a deaeration tank connected to a lower end of the mixing tube, An air pump is connected to the mixing pipe and the degassing tank, respectively. A spiral groove is formed on the inner surface of the mixing tube.

Embodiment 1 is an example in which samples are not mixed. Five milliliters of a sample to be analyzed and 0.25 milliliter of analytical reagent are injected into a mixing tube for 50 seconds to form a mixed solution.

Thereafter, air was injected into the mixing tube using an air pump connected to the upper end of the mixing tube.

After the mixed liquid discharged from the mixing tube was transferred to the degassing vessel, air was injected into the degassing vessel for 10 seconds by using an air pump connected to the degassing vessel and degassed.

The degassed mixture was transferred to the optical system to measure the copper concentration.

The copper concentration was measured 10 times.

Comparative Example  One

Copper concentration was measured in the same manner as in Example 1, except that 5 milliliters of the sample to be analyzed was injected for 50 seconds and then 0.25 milliliter of analytical reagent was injected separately for 50 seconds.

Example  2

Copper sulfate was dissolved in ultrapure water to prepare copper standard solutions of 2, 5, 7 and 10 ppm, respectively. In Example 2, copper concentration was measured in the same manner as in Example 1, except that 0.25 milliliter of sample to be analyzed by dilution with high concentration wastewater, 4.75 milliliters of diluent and 0.25 milliliter of analytical reagent were injected into a mixing tube for 50 seconds .

In the same manner, copper concentration was measured ten times.

Comparative Example  2

0.25 milliliter of the sample to be analyzed was injected for 50 seconds, then 4.75 milliliters of the diluted solution was injected for 50 seconds, and then 0.25 milliliter of the analytical reagent was injected into the mixing tube sequentially for 50 seconds. Were measured. The copper concentration was measured 10 times.

Comparative Example  3

Copper concentration was measured in the same manner as in Example 2, except that 200-ppm copper standard solution prepared by dissolving copper sulfate in ultrapure water was used as a sample to be analyzed and a spiral groove was not formed on the inner surface of the mixing tube .

Comparative Example  4

Copper concentration was measured in the same manner as in Example 2 except that 200 ppm copper standard solution prepared by dissolving copper sulfate in ultrapure water was used as a sample to be analyzed and air was not supplied from the air pump connected to the upper end of the mixing tube The copper concentration, standard deviation and coefficient of variation measured in Example 1 and Comparative Example 1 are shown in Table 1.

Copper concentration (ppm)
Number of times Example 1 Comparative Example 1 2 5 7 10 2 5 7 10 One 2.02 5.12 6.89 10.24 1.84 5.85 7.92 9.45 2 2.05 4.87 7.02 10.37 1.75 5.45 7.45 9.23 3 1.98 5.05 7.03 10.09 1.68 5.21 7.65 9.63 4 2.04 5.02 7.12 10.32 2.06 5.24 7.21 10.46 5 2.07 4.95 6.95 10.42 2.02 5.42 7.85 10.47 6 1.95 4.96 6.97 10.32 2.05 4.66 6.45 9.25 7 2.07 4.96 7.13 10.42 2.68 4.52 6.78 9.56 8 2.02 5.02 7.11 10.43 2.45 5.39 7.62 9.24 9 2.03 5.08 7.05 10.35 2.14 5.72 7.82 11.12 10 2.04 5.03 7.06 10.46 1.86 4.34 6.56 11.02 Average (PPM) 2.027 5.006 7.033 10.342 2.053 5.18 7.331 9.943 Standard Deviation 0.038 0.072 0.078 0.110 0.311 0.509 0.552 0.750 Coefficient of variation (%) 1.86 1.45 1.12 1.07 15.17 9.83 7.53 7.54

* Coefficient of variation = (standard deviation / average) X100

The copper concentration, standard deviation and coefficient of variation measured in Example 2 and Comparative Example 2 are shown in Table 2.

Copper concentration (ppm)
Number of times Example 2 Comparative Example 2 50 100 150 200 50 100 150 200 One 48.9 100.9 152.4 203.5 44.2 94.2 134.5 176.5 2 49.6 101.7 152.8 201.5 46.3 93.4 137.8 164.5 3 51.2 99.5 150.7 200.4 41.8 85.4 154.9 189.4 4 50.4 99.1 150.9 202.8 49.1 115.4 163.4 179.5 5 51.9 101.5 147.5 201.7 55.6 98.1 138.5 204.6 6 51.8 100.8 149.5 198.2 54.3 94.8 146.9 206.4 7 50.4 98.4 149.6 198.5 57.1 93.1 164.8 182.5 8 50.6 101.8 152.5 201.1 58.9 100.5 136.5 187.2 9 49.8 99.2 151.7 202.6 41.5 86.5 145.2 164.9 10 50.7 100.5 152.8 198.6 45.3 84.3 137.8 178.5 Average (PPM) 50.53 99.1 151.04 200.89 49.41 94.57 146.03 183.4 Standard Deviation 0.946 1.210 1.755 1.912 6.546 9.067 11.304 14.205 Coefficient of variation (%) 1.87 1.22 1.16 0.95 13.25 9.59 7.74 7.75

* Coefficient of variation = (standard deviation / average) X100

The copper concentration, standard deviation and coefficient of variation measured in Comparative Example 3 are shown in Table 3.

Number of times One 2 3 4 5 6 7 8 9 10 Average Standard Deviation Variance
Coefficient Copper concentration
(ppm) 193.4 186.4 193.4 185.7 216.7 196.4 194.6 204.9 176.2 164.7 191.2 14.40 7.53

* Coefficient of variation = (standard deviation / average) X100

The copper concentration, standard deviation and coefficient of variation measured in Comparative Example 4 are shown in Table 4.

Number of times One 2 3 4 5 6 7 8 9 10 Average Standard Deviation Variance
Coefficient Copper concentration
(ppm) 201.4 205.7 198.5 199.4 172.6 204.6 168.4 201.8 197.6 185.2 194.4 13.87 7.13

* Coefficient of variation = (standard deviation / average) X100

1: sample to be analyzed Pump 2: dilution water injection pump
3: Air pump 4: Analytical reagent injection pump
5: Mixing tube 6: Melting tank
7: Air pump 8: Two-way electric valve
9: Feed pump 10: Optical system
11: Three-way electric valve
12: Target sample to be analyzed 13: Dilution water induction tube
14: Analysis reagent guide tube 15: Mixing tube
16: air induction pipe 17: sample discharge pipe
18: Tube connector
19: sample return induction tube 20: first analysis reagent injection pump
21: second analytical reagent injection pump 22: sample return pump
23: Three-way electric valve
100: Sample to be analyzed
200: Dilution tank
300: Analysis reagent tank
301: First analytical reagent tank
302: Second analytical reagent tank

Claims (3)

A sample tank containing the sample to be analyzed; A diluent bath containing a diluent; An analytical reagent bath containing analytical reagent containing carbon disulfide and diethanolamine; A mixing tube in which a spiral groove is formed on the inner surface so that the sample to be analyzed, the diluting solution, and the analysis reagent are respectively injected from the sample water to be analyzed, the diluting water tank, and the analysis reagent water tank; A degassing vessel for introducing the mixed liquor mixed in the mixing tube to remove bubbles contained in the mixed liquor; And an optical system for measuring the concentration of copper from the mixed liquid from which air bubbles have been removed from the degassing vessel. The method for analyzing copper concentration in water includes the following steps:
(S1) injecting a sample to be analyzed, a diluent, and an analytical reagent containing carbon disulfide and diethanolamine into a mixing tube having a helical groove formed on its inner surface for the same period of time;
(S2) injecting air into the mixing tube;
(S3) transferring the mixed liquid discharged from the mixing tube to the degassing vessel after the air is injected in the step (S2), thereby removing bubbles of the mixed liquid; And
(S4) A step of measuring the concentration of copper from the mixture liquid from which air bubbles have been removed from the degassing vessel.
The method according to claim 1, wherein air is injected into the degassing vessel in the step (S3).
The method according to claim 1,
Wherein the mixing tube has a cylindrical shape with a diameter of 1 to 3 mm, the spiral groove has a depth of 0.5 to 2 mm, a distance between the spirals is 0.5 to 1.4 cm,
The mixing tube is connected to the sample introduction tube, the diluting solution inducing tube and the analyte reagent induction tube for inducing the injection of the sample to be analyzed, the diluting solution and the analytical reagent into the inside, and the sample induction tube, the diluting solution inducing tube, The inner diameter of the tube is 0.5 to 2 mm,
A peristaltic pump is disposed between the mixing tube and the sample water tank, the diluent water tank, and the analysis reagent water tank,
Wherein the peristaltic pump has a rotation speed of the drive motor of 20 to 250 rpm,
Wherein the peristaltic pump is connected to a mixing tube, a sample water sample to be analyzed, a diluent water tank, and an analysis reagent water tank by tubes each having an inner diameter of 0.5 to 6 mm.

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