KR102231002B1 - Method for measuring organic materials using UV LED - Google Patents

Abstract

The present invention relates to a method for measuring an organic substance using a UV led which can easily measure concentration of an organic substance in water by using UV absorption with wavelength of 254 nm. Thus, the present invention measures the organic substance in the water by using the UV absorption with the wavelength of 254 nm, thereby having short measurement time and responding time, continuously outputting a measurement valve, and removing a special pretreatment process, and having excellent sensitivity to significantly reduce time for an on-site trial run and correction.

Description

Method for measuring organic materials using UV LED

The present invention relates to a method for measuring organic substances using a UV LED, and more particularly, to a method for measuring organic substances using a UV LED, which enables the concentration of organic substances in water to be easily measured using ultraviolet absorbance at a wavelength of 254 nm. will be.

Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) represent the amount of oxygen consumed when various organic compounds in water are oxidized by an oxidizing agent, and are the most widely used indicators of organic water pollution. have.

However, the measurement results such as COD and TOC are greatly affected by the type, concentration, reaction temperature, and reaction time of the oxidizing agent, and the analysis methods adopted in each country are different, and controversy over the establishment of the analysis method continues. have.

As an example, the measurement time for COD and TOC is at least 15 minutes (TOC) and 1 hour (COD), and errors may occur depending on the condition of the instrument and reagents and the skill of the operator, and secondary There is a problem that contamination and real-time field application are difficult.

Moreover, the COD and TOC measuring devices generally used incur expensive installation costs and high operating costs, require periodic maintenance, and take 15 minutes to 1 hour or more for one measurement. Difficulty in process control.

In order to compensate for this problem, various follow-up technologies such as electrochemical methods have been developed and used, but they suffer from problems such as reduced sensitivity, frequent electrode replacement, and high maintenance costs.

Accordingly, there is a trend in the development of a technique for measuring COD/TOC using 254 nm of the absorbance photometric method with excellent sensitivity, as well as a short measurement time and no special pretreatment process.

Publication Patent No. 2001-0028246 (2001.04.06)

The present invention was devised in consideration of the above points, and by enabling the measurement of organic substances in water using UV (ultraviolet) absorbance of 254 nm wavelength, measurement time and response time are short, and continuous output of measured values The purpose of this is to provide a method for measuring organic substances using UV LEDs that can greatly shorten the on-site commissioning and calibration time because it is possible and does not require a special pretreatment process and has excellent sensitivity.

In order to achieve the above object, the present invention includes: turning on a UV LED mounted inside a housing to irradiate UV light of a wavelength of 254 nm from the UV LED toward a beam splitter; Filling the sample inlet of the housing with an organic substance concentration measurement target; Dividing the UV light irradiated from the UV LED into 50:50 by the beam splitter; 50% of the UV light divided by the beam splitter passes through the window and is irradiated to the sample introduced into the sample inlet, so that the organic material in the sample meets the UV light with a wavelength of 254 nm to absorb the UV light; The UV light absorbed by the organic material in the sample passes through a window and is condensed by a focusing lens; Receiving the absorbed UV light condensed by the focusing lens by the sample detector and sensing it as a signal for classifying an organic substance concentration; It provides a method for measuring an organic material using a UV LED comprising a.

The organic material measuring method of the present invention is characterized in that it further comprises the step of receiving the 50% of UV light divided by the beam splitter 30 for signal compensation purposes by the reference detector 40.

Preferably, in a single-band type band filter disposed in front of the reference detector and the sample detector, only UV light having a wavelength of 254 nm is passed through the reference detector and the sample detector, respectively.

The organic material measurement method of the present invention comprises the steps of amplifying a UV light signal output from the sample detector into a signal having a size that can be interpreted by an amplifier; Converting the signal amplified by the amplifier into a digital signal in an analog-to-digital converter; And converting the digital signal converted by the analog-to-digital converter into a concentration of an organic substance in a sample by a main control unit and calculating a numerical value. It characterized in that it further comprises.

Through the above-described problem solving means, the present invention provides the following effects.

First, by making it possible to measure the concentration of organic substances in water using UV (ultraviolet) absorbance of 254 nm wavelength, the measurement time and response time are short, continuous output of the measured value is possible, and no special pretreatment is required. In addition, due to its excellent sensitivity, it can greatly shorten the on-site commissioning and calibration time.

Second, the domestic emission standards of COD and TOC used to estimate the pollution level of sewage are COD 20 ~ 130mg/L or less and TOC 12 ~75mg/L or less, respectively, and accurate COD and TOC can be measured compared to these emission standards. Therefore, it is possible to realize efficient process control by monitoring organic pollutants in real time.

1 is an external view showing an organic material measuring device using a UV LED according to the present invention,
2 is a block diagram showing the internal configuration of an organic material measuring device using a UV LED according to the present invention,
3 is a block diagram showing a configuration of processing a UV light signal measured by an organic material measuring device using a UV LED according to the present invention as a digital signal,
Figure 4 is a flow chart showing an organic material measurement method using a UV LED according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In general, as organic substances in water, humic acid and polycyclic aromatic hydrocarbons are major pollutants, and they are not easily decomposed in nature, so they may be absorbed and accumulated by animals or humans. It is necessary to accurately measure the concentration of organic substances such as COD and TOC in water such as rivers.

The COD and TOC are indicators representing the pollution state by continuously measuring the amount of organic carbon in sewage, river water, and lake water, and these indicators represent the amount of oxygen required to oxidize pollutants such as organic matter in water, and COD and TOC values This increase means a state in which organic matter increases, so it can be used to estimate the approximate value of pollution, and in Korea, emission standards are generally set at COD 20 ~ 130mg/L or less and TOC 12 ~75mg/L or less.

Accordingly, there is a need for a device capable of measuring COD and TOC accurately compared to the emission standard.

To this end, the present invention is to provide an organic material measuring device using a UV LED capable of accurately measuring the organic material in water by using the UV (ultraviolet) absorbance of a wavelength of 254 nm.

Here, UV ₂₅₄ means ultraviolet absorbance at a wavelength of 254 nm, and particularly, if a large amount of humic acid and aromatic carbon compounds are contained in the sample to be measured (e.g. wastewater, river water, lake water, etc.), the absorbance is large.

1 is an external view showing an organic material measuring device using a UV LED according to the present invention, Figure 2 is a configuration diagram showing the internal configuration of the organic material measuring device using a UV LED according to the present invention.

The organic material measuring device using the UV LED of the present invention is in the form of a cylindrical immersion sensor, and the housing 10 forming the exterior is made of a metal material (eg, SUS) or a plastic resin material (eg, PEEK).

A sample inlet 12 through which samples such as wastewater, river water, lake water, and the like can be filled is formed in a concave portion at one side of the housing 10.

Preferably, the upper and lower portions of the sample inlet 12 protect a light source and a light-receiving element, and as a means for transmitting light after absorption, a general glass material does not pass light of 300 nm or less, so a wavelength of 254 nm (λ=254 nm) A window 14 made of quartz, which can easily pass UV light of ), is mounted.

A UV LED 20, a beam splitter 30, and a reference detector 40 are mounted in a predetermined arrangement inside the lower side of the housing 10 with the sample inlet 12 as a center. do.

More specifically, a UV LED 20 that irradiates UV light with a wavelength of 254 nm (λ = 254 nm) is mounted at the lowest position inside the housing 10, and the UV LED 20 and the window 14 A beam splitter 30 disposed between and dividing the UV light irradiated by the UV LED 20 into 50:50 is mounted, and at one position of the beam splitter 30, 50% of the UV light divided by the beam splitter A reference detector 40, which is a type of light-receiving element, is disposed to correct the signal.

At this time, the reason why the UV LED 20 is adopted as a specification for irradiating UV light with a wavelength of 254 nm (λ = 254 nm) is because it is a wavelength at which the organic material in the sample reacts.

Preferably, a reflector 22 for reflecting and emitting light in parallel is disposed around the UV LED 20.

In addition, the reference detector 40 is a kind of light-receiving device that receives 50% of the UV light divided by the beam splitter for signal correction, and is to be adopted as a photo diode capable of detecting a UV light wavelength of 254 nm. I can.

A focusing lens 50 and a sample detector 60 are mounted in a predetermined arrangement inside the upper portion of the housing 10 with the sample inlet 12 as a center.

More specifically, UV light that has passed through the window 14 in the upper interior of the housing 10 centering on the sample inlet 12, that is, absorbed from the organic material in the sample introduced into the sample inlet 12. A focusing lens 50 that collects and condenses the UV light after it is collected, and a sample detector 60, which is a kind of light-receiving element for receiving the UV light collected by the focusing lens 50, are mounted side by side.

Likewise, the sample detector 60 is also a type of light-receiving device, and may be adopted as a photo diode capable of detecting a UV light wavelength of 254 nm.

Preferably, in front of the reference detector 40 and in front of the sample detector 60, a single-band type band filter 70, which allows only UV light having a wavelength of 254 nm (within ±10 nm) to pass through, can pass through. band bandpass Filter) is placed.

Here, a method for measuring organic substances based on the apparatus for measuring organic substances using a UV LED of the present invention having the above configuration will be described with reference to FIGS. 2 to 4.

First, the UV LED 20 mounted inside the housing 10 is turned on so that UV light having a wavelength of 254 nm (λ=254 nm) is irradiated from the UV LED 20 to the beam splitter 30 (S101).

In this case, the UV light irradiated from the UV LED 20 may be reflected by the reflector 22 and emitted in parallel toward the beam splitter 30.

In addition, a sample to be measured for the concentration of organic substances such as sewage, river water, and lake water is filled into the sample inlet 12 of the housing 10 (S102).

Subsequently, the UV light irradiated from the UV LED 20 is divided into 50:50 by the beam splitter 30 (S103).

Subsequently, 50% of the UV light split by the beam splitter 30 passes through the window 14 and is irradiated to the sample flowing into the sample inlet 12, so that the organic material in the sample is at a wavelength of 254 nm (λ=254 nm). A phenomenon of absorbing UV light occurs by meeting the UV light of (S104).

In this case, a phenomenon in which the organic material in the sample absorbs UV light is the same as an excitation phenomenon in which light is blocked.

Subsequently, the UV light absorbed by the organic material in the sample passes through the window 14 and is condensed by the focusing lens 50 to improve sensitivity (105).

In this case, since UV light may be spread by refraction, scattering, or the like in the process of passing through the sample, the focusing lens 50 collects UV light to minimize sensitivity loss.

Subsequently, the absorbed UV light condensed by the focusing lens 50 is received by the sample detector 60 and sensed as a signal for classifying the concentration of organic substances (S106).

At this time, by passing only UV having a wavelength of 254 nm (within ±10 nm) in the single-band type band filter 70 disposed in front of the sample detector 60, 254 nm (± Within 10 nm) only UV light of a wavelength is received, and the received UV light signal can be used as a signal for discriminating the concentration of organic substances.

Meanwhile, the remaining 50% of the UV light divided by the beam splitter 30 is received by the reference detector 40, and the received UV light is used for signal compensation (S107).

At this time, by passing only UV having a wavelength of 254 nm (within ±10 nm) in the single-band type band filter 70 disposed in front of the reference detector 40, 254 nm (within ±10 nm) in the reference detector 40 UV light of wavelength can be easily received and used for signal compensation purposes.

According to the present invention, as shown in FIG. 3, the sample detector 60 includes an amplifier 80 (Op-amp) and an analog-to-digital converter (Op-amp) 80 to amplify and convert the received UV light signal into an electrical signal. 90, ADC) and the main control unit 100 (MCU: Main Control Unit) are sequentially connected to enable signal transmission.

Since the UV light signal output from the sample detector 60 is very small, it is difficult to interpret the signal by itself, and it contains noise components due to various causes, so it is adopted as an op-amp (operational amplifier) which is a direct current amplifier. The noise component is effectively removed from the amplifier 80 and amplifies the original signal having a small size into a signal having an interpretable size (S108).

Subsequently, the signal amplified by the amplifier 80 is converted into a digital signal by the analog-to-digital converter 90 (S109).

Next, when the digital signal converted by the analog-to-digital converter 90 is input to the main control unit 100, the digital signal input from the main control unit 100 is converted into an organic substance (COD/TOC, etc.) in the sample. Converted to the concentration of and expressed as a numerical value (S110).

In this way, the concentration value of the organic material calculated by the main control unit 100 is displayed on the monitor so that the experimenter can check it.

As seen above, by making it possible to easily measure the concentration of organic substances in water using UV (ultraviolet) absorbance of 254 nm wavelength, measurement time and response time are short, continuous output of measured values is possible, and special pretreatment Not only does it require a process, but it has excellent sensitivity and can greatly shorten the time for on-site commissioning and calibration.

Meanwhile, the housing 10 may be made of a metal material, and an anti-corrosion coating layer may be applied to the housing 10 of the metal material to prevent corrosion of the metal surface.

The coating material of this anticorrosive coating layer is triethanolamine 15% by weight, indiazole 25% by weight, hafnium 20% by weight, molybdenum emulsified (MoS ² ) 10% by weight, titanium oxide (TiO ² ) 15% by weight, propionamide 15% by weight It is composed of %, and the coating thickness can be formed to 8㎛.

Triethanolamine, indiazole, and propionamide play a role in preventing corrosion and discoloration.

Hafnium is a transition metal element with corrosion resistance and plays a role in having excellent waterproof and corrosion resistance.

Molybdenum emulsified plays a role of imparting wetness and lubricity to the surface of the coating film.

Titanium oxide is added for the purpose of fire resistance and chemical stability.

The reason why the ratio of the constituent components and the coating thickness were numerically limited as described above is that the present inventors have repeatedly failed several times and analyzed through the test results, and as a result, the optimum anti-corrosion effect was exhibited at the ratio.

In addition, the UV LED 20 may be coated with an antifouling coating layer made of a composition for antifouling coating so that adhesion prevention and removal of pollutants can be effectively achieved.

The antifouling coating composition contains cocoamphodiacetate and alkyl glycol ether in a molar ratio of 1:0.01 to 1:2, and the total content of cocoamphodiacetate and alkyl glycol ether is 1 to 10% by weight based on the total aqueous solution. to be.

The molar ratio of the cocoamphodiacetate and the alkyl glycol ether is preferably 1:0.01 to 1:2.When the molar ratio is out of the above range, the applicability of the UV LED 20 decreases or the surface moisture adsorption increases after application. Thus, there is a problem in that the coating film is removed.

The cocoamphodiacetate and alkyl glycol ether are preferably 1 to 10% by weight in the total composition aqueous solution, and if it is less than 1% by weight, there is a problem that the applicability of the UV LED 20 decreases, and if it exceeds 10% by weight, it Crystal precipitation is liable to occur due to an increase in the film thickness.

On the other hand, as a method of applying the present antifouling coating composition to the UV LED 20, it is preferable to apply it by a spray method. In addition, the thickness of the final coating film of the UV LED 20 is preferably 550 to 2000 Å, more preferably 1100 to 1900 Å. If the thickness of the coating film is less than 550 Å, there is a problem of deterioration in the case of high-temperature heat treatment, and if it exceeds 2000 Å, crystal precipitation on the coated surface is liable to occur.

In addition, the present antifouling coating composition may be prepared by adding 0.1 mol of cocoamphodiacetate and 0.05 mol of alkyl glycol ether to 1000 ml of distilled water, followed by stirring.

In addition, a sound-absorbing layer may be provided on the inner surface of the housing 10. As the sound-absorbing layer, a spunbond nonwoven fabric may be used. The types of fibers constituting the sound-absorbing layer made of spunbond nonwoven fabric are formed of polyester fibers.

It is preferable that the thickness of the sound-absorbing layer is 0.04 to 1.5 mm. When the thickness of the sound-absorbing layer is less than 0.04 mm, a sufficient sound-absorbing effect is not obtained, and when the thickness of the sound-absorbing layer exceeds 1.5 mm, sufficient space inside the signal processing unit 200 and the noise removing unit 300 is not secured.

The unit weight of the sound-absorbing layer is preferably ^{0.6 to 90 g/m 2.} In the 0.6g / m ² but less than the sufficient sound absorbing effect is not obtained, and it is not preferable not possible to secure the light weight of the signal processor 200 and a noise remover 300 is more than 90g / m ^2.

The fineness of the fibers constituting the sound-absorbing layer is preferably in the range of 0.6 to 25 decitex. If it is less than 0.6 decitex, it is difficult to absorb low-frequency noise and cushioning property is also lowered, which is not preferable. In addition, if it exceeds 25 decitex, it is difficult to absorb high-frequency noise, which is not preferable.

The tensile strength of the spunbond nonwoven fabric of the sound-absorbing layer is 9Kgf/cm2.

Since the sound-absorbing layer is provided inside the housing 10, noise is reduced when the equipment is driven to measure organic materials using UV LEDs.

In addition, a vibration absorbing part made of a rubber material may be further installed on the bottom surface of the housing 10.

This vibration-absorbing part may be made of a rubber material, and the raw material content ratio of this vibration-absorbing part is 55% by weight of rubber, 6% by weight of organic acid cobalt salt, 6% by weight of naphthalic anhydride, 22% by weight of carbon black, 3C (N -PHENYL-N'-ISOPROPYL-P-PHENYLENEDIAMINE) 6% by weight and 5% by weight of sulfur are mixed.

Carbon black is added to increase or improve abrasion resistance and thermal conductivity, and cobalt salts of organic acids and naphthalic anhydride are added to improve adhesion.

3C (N-PHENYL-N'-ISOPROPYL- P-PHENYLENEDIAMINE) is added as an antioxidant, and oil is added to act as an accelerator.

Accordingly, in the present invention, since the elasticity, toughness and rigidity of the vibration absorbing unit are increased, durability is improved, and thus the life of the vibration absorbing unit is increased.

The reason why the rubber constituents and constituents were limited and the numerical value of the mixing ratio was limited is that the inventors have repeatedly failed several times and analyzed through the test results, showing the optimum effect in the above constituents and numerically limited ratio. I got it.

10: housing
12: sample inlet
14: Windows
20: UV LED
22: reflector
30: beam splitter
40: reference detector
50: focusing lens
60: sample detector
70: single-band type band filter
80: amplifier
90: analog-to-digital converter
100: main control unit

Claims (3)

Turning on the UV LED 20 mounted inside the housing 10 to irradiate UV light having a wavelength of 254 nm from the UV LED 20 toward the beam splitter 30;
Filling the sample inlet 12 of the housing 10 with a sample to be measured for the concentration of organic substances;
Dividing the UV light irradiated from the UV LED 20 into 50:50 by the beam splitter 30;
50% of the UV light divided by the beam splitter 30 passes through the window 14 and is irradiated to the sample flowing into the sample inlet 12, so that the organic material in the sample meets the UV light of 254 nm wavelength to generate UV light. Absorbing light;
The UV light absorbed by the organic material in the sample passes through the window 14 and is condensed by the focusing lens 50;
Receiving the absorbed UV light condensed by the focusing lens 50 by the sample detector 60 and sensing it as a signal for classifying the concentration of organic substances;
50% of the UV light divided by the beam splitter 30 is received by the reference detector 40 for signal compensation;
In the single-band type band filter 70 disposed in front of the reference detector 40 and the sample detector 60, only UV light having a wavelength of 254 nm is passed through the reference detector 40 and the sample detector 60, respectively;
Amplifying the UV light signal output from the sample detector (60) into a signal having an interpretable size by the amplifier (80);
Converting the signal amplified by the amplifier (80) into a digital signal by an analog-to-digital converter (90); And
Converting the digital signal converted by the analog-to-digital converter (90) into a concentration of organic substances in the sample by the main control unit (100) and calculating a numerical value;
The sample detector 60 and the reference detector 40 are made of a photodiode sensing a UV light wavelength of 254 nm;
A corrosion protection coating layer is applied to the housing 10, and the coating material of the corrosion protection coating layer is triethanolamine 15% by weight, indiazole 25% by weight, hafnium 20% by weight, molybdenum emulsified (MoS ² ) 10% by weight, oxidation Titanium (TiO ² ) 15% by weight, consisting of 15% by weight of propionamide, the coating thickness is formed to 8㎛;
A vibration absorbing part is installed on the bottom surface of the housing 10, and the raw material content ratio of the vibration absorbing part is 55% by weight of rubber, 6% by weight of cobalt salt of organic acid, 6% by weight of naphthalic anhydride, 22% by weight of carbon black, 3C (N-PHENYL-N'-ISOPROPYL-P-PHENYLENEDIAMINE) 6% by weight and 5% by weight of sulfur are mixed. delete delete

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