JP3316485B2 - Dioxin analysis method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for analyzing dioxins for measuring the concentration of harmful substances such as organic halogen compounds in landfill leachate or industrial wastewater, and wastewater using the same. Regarding the processing system.

[0002]

2. Description of the Related Art Conventionally, wastewater such as landfill leachate and industrial wastewater is prepared in a preparation tank after adjusting the amount of water, pH, etc., and then organic substances and nitrogen components are removed in a biological treatment tank and coagulated in a coagulation sedimentation tank. Aggregation by the addition of an agent separates heavy metal and SS (floating substance) components. Thereafter, the supernatant liquid is decomposed by the accelerated oxidation treatment of the hardly decomposable organic substances such as dioxins in the liquid, and is discharged as treated water through a sand filtration tower and an activated carbon adsorption tower.

[0003] As a method for purifying water containing dioxins, which are hardly decomposable organic substances, there is a method in which peroxide water is added to water containing an organic chlorine compound and the compound is decomposed by irradiating ultraviolet rays. Proposed. Further, a method of decomposing dioxins by introducing ozone instead of ultraviolet irradiation has been proposed.

[0004]

Conventionally, the analysis of dioxins is carried out by repeating the concentration operation from waste water using an organic solvent, and it usually takes a long time of 70 hours or more, and it is difficult to measure quickly. Met. For this reason, in order to reduce the concentration of dioxins in wastewater, ultraviolet irradiation or a large amount of ozone is injected and treated by the above-described method, but measurement according to the concentration of dioxins in wastewater is performed. At present, it is difficult to perform the decomposition treatment in an excessive amount, and the decomposition treatment in accordance with the concentration of harmful substances such as dioxins in the wastewater is desired.

In view of the above, the present invention provides a dioxin analysis method and apparatus capable of promptly analyzing the concentration of dioxins in the wastewater discharged from landfills and in the wastewater washed after cleaning the inside of a refuse incinerator. With the goal.

[0006]

Means for Solving the Problems The invention of a method for analyzing dioxins according to claim 1 of the present invention, which solves the above-mentioned problems, comprises:
A metal colloid acetonitrile solution is mixed with the solution to be measured, the mixture is irradiated with an argon laser beam, the dioxins in the mixture are subjected to Raman scattering, the Raman scattered light is detected, and the dioxins in the solution to be measured are detected. It is characterized by measuring the concentration.

The invention of claim 2 is characterized in that, in claim 1, the metal colloid is a silver colloid.

[0008]

[0009]

[0010] The invention of a dioxin analyzer according to claim 3 is a mixing means for mixing a metal colloid acetonitrile solution with a solution to be measured, and a container for introducing the mixed solution.
A laser device for irradiating an argon laser beam and a photodetector for detecting Raman scattered light of dioxins generated by the laser irradiation are provided.

[0011]

[0012]

According to a fourth aspect of the present invention, there is provided a wastewater treatment system for decomposing and processing harmful substances in wastewater, wherein the dioxin analyzer according to the third aspect is capable of measuring the concentration of dioxins in wastewater. And detecting the concentration of dioxins without time delay, and decomposing dioxins in the wastewater in the presence of hydroxy radicals according to the detected concentration of dioxins.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

The dioxin analyzer 10 according to the present embodiment mixes a silver colloid solution 11 made of silver nitrate (AgNO ₃ ), a silver colloid acetonitrile solution 11 made of acetonitrile (CH ₃ CN), and a solution 12 to be measured. Mixing means 13, a laser device 16 for irradiating a laser beam 16a into a cell 15 into which the mixed liquid 14 has been introduced, and a photodetector 18 for detecting Raman scattered light 17 of dioxins generated by the laser irradiation And an amplifier 19a for amplifying the obtained current signal, and an A / D converter 19 for converting an analog signal of the amplifier into a digital signal.
b, and a data processing means 19 comprising a monitor 19c for performing video processing on the signal.
Using 0, the solution 16 to be measured is irradiated with the laser light 13 and Raman scattered light is detected to measure the concentration of dioxins in the solution to be measured.

The above silver colloid solution is prepared by reducing an aqueous silver nitrate solution with sodium tetrahydroborate or sodium citrate. Since the silver colloid acetonitrile solution 11 is stable for several hours, it is mixed according to the frequency of measurement.

Although silver is used as the metal colloid solution in the present invention, a gold colloid solution using gold instead of silver or a copper colloid solution using copper may be used.

The laser beam irradiated on the surface of the solution to be measured is an argon ion laser of 488.0 nm or 514.5 nm.
An oscillation line in the visible light region of nm may be used as the excitation light source.

According to the present invention, the effect of adsorbing and concentrating dioxin on the surface of the silver colloid and the surface-sensitized Raman effect improve the measurement sensitivity, enable high-sensitivity analysis of dioxins, and reduce dioxins in wastewater. Pg /
Detection can be performed down to a low liter level. Therefore, it does not require an analysis time of about 70 hours or more as in the conventional extraction method for measuring the concentration of dioxins in wastewater,
The concentration of dioxins in wastewater can be quickly analyzed in real time.

An example of a wastewater treatment system for decomposing harmful substances in wastewater using this apparatus will be described.

As shown in FIG. 2, the wastewater treatment system according to the present embodiment includes a dioxin analyzer 10 capable of measuring the concentration of dioxins in wastewater shown in FIG. UV lamp 20 for irradiation
And an ozone-containing gas 21 to generate a hydroxy radical (.OH radical), a dioxin decomposing device 22, and a coagulation sedimentation treatment equipment 26 having a coagulation tank 23, a floc forming tank 24, and a coagulation sedimentation tank 25. It becomes. According to this system, the dioxin analyzer 10 detects the dioxin concentration without time delay, adjusts the amount of generated hydroxy radicals according to the detected dioxin concentration, and contains the harmful substances of dioxins. The dioxins in the wastewater (raw water) 27 are decomposed by the dioxin decomposer 22, and then the suspension is coagulated and settled in the coagulation and sedimentation equipment 26 to separate and purify the coagulated sludge 28.
And Accordingly, the ability to decompose dioxins can be adjusted according to the current state of the content of harmful substances such as dioxins in the raw water 27, and efficient raw water decomposition can be achieved. Therefore, for example, when the concentration of dioxins in the raw water 27 exceeds a certain value (for example, 20 to 30 pg / liter), an ozone-containing gas and hydrogen peroxide can be supplied to start the dioxin decomposition treatment. . The specified value is not limited, and may be changed according to the emission regulation. As a result, it is not necessary to constantly generate hydroxy radicals for decomposing dioxins in the conventional wastewater treatment, so that the treatment efficiency of the treatment system and the labor of the treatment equipment can be reduced.

The coagulation and sedimentation equipment 23 is for coagulating and sedimenting solids and colloids in the raw water 27 in the coagulation and sedimentation tank 25 by adding a coagulant 31 and an alkali (such as NaOH) 32. The reason why the alkali is added is to adjust pH since the pH is lowered by the agglutination reaction. Further, depending on the required quality of the treated water, sand filtration means, activated carbon adsorption means, and the like are appropriately added after the coagulation and sedimentation treatment.

Here, the dedicated dioxin decomposer 22 generates a hydroxy radical (.OH radical) by using a hydrogen peroxide solution (H ₂ O ₂ ) and ozone in combination, and converts the dioxin by the hydroxy radical. A decomposition method that almost completely decomposes and detoxifies is adopted.

Here, in the present embodiment, the hydroxy radical generating means is exemplified by a combination of hydrogen peroxide solution (H ₂ O ₂ ) and ozone. Examples include a method of irradiating ultraviolet rays with a lamp, a method of irradiating ultraviolet rays with an ultraviolet lamp using ozone and hydrogen peroxide in combination, and a method of irradiating ultraviolet rays to hydrogen peroxide with an ultraviolet lamp. The method of irradiating the above-mentioned ozone with an ultraviolet ray by an ultraviolet lamp (for example, a low-pressure mercury lamp: output of 10 to 200 W) is to irradiate the ozone (ozone concentration of 10 g / m ³ or more) with ultraviolet rays having wavelengths of 185 nm and 254 nm. Is to occur. The above-mentioned method of using ozone and hydrogen peroxide in combination uses an injection amount of hydrogen peroxide of 10 to 5000 mg / liter, an injection amount of ozone of 50 to 5000 mg / liter, and irradiates the ultraviolet light with an ultraviolet lamp. Generates hydroxy radicals. In the method of irradiating the hydrogen peroxide with ultraviolet rays using an ultraviolet lamp, the amount of hydrogen peroxide to be injected is set to 10 to 5000 mg / liter, and hydroxyl radicals are generated by irradiating the ultraviolet rays with the ultraviolet lamp.

Further, the coagulation and sedimentation equipment 26 may be integrated with a dioxin decomposer to reduce the size.

Here, the dioxins to be decomposed are polychlorinated dibenzo-p-dioxins (PCD
Ds) and polychlorinated dibenzofurans (PCDFs). These are said to be generated in trace amounts when chlorine compounds and certain organic chlorine compounds are burned, and are chemically colorless crystals. Depending on the number of chlorines, there are from monochloride to octachloride, 75 isomers for PCDDs and 1 for PCDFs.
35 kinds and, of these, especially tetrachloride dibenzo -p- dioxin (T ₄ CDD) is known as having the strongest toxicity. In addition, as harmful chlorinated aromatic compounds, in addition to dioxins, various organic chlorine compounds (for example, aromatic compounds such as phenol and benzene (for example, chlorobenzenes, chlorophenol and chlorotoluene) ), Chlorinated alkyl compounds, etc.) and must be removed from the wastewater to be discharged as treated water.

PCBs (polychlorinated biphenyls)
Is a generic term for compounds in which several chlorine atoms are added to biphenyl, and there are isomers depending on the number of chlorine substitutions and substitution positions.
Typical are 2,6-dichlorobiphenyl, 2,2'-dichlorobiphenyl, 2,3,5-trichlorobiphenyl, etc., which are highly toxic and may generate dioxins when incinerated. Known as
In order to discharge as treated water, it is necessary to remove it from the wastewater.

[0028]

As described above, according to the first aspect of the present invention, a solution to be measured is mixed with a metal colloid acetonitrile solution, and the mixed solution is irradiated with an argon laser beam. The dioxins in the liquid are subjected to Raman scattering, and the Raman scattered light is detected, so that the dioxin concentration in the solution to be measured can be quickly measured without the need for time for dioxin analysis as in the conventional method. it can.

According to the second aspect of the present invention, since the metal colloid in the first aspect is a silver colloid, dioxins can be detected with high sensitivity.

[0030]

[0031]

According to the third aspect of the present invention, there is provided a mixing device for mixing a metal colloid acetonitrile solution with a solution to be measured, and a laser for irradiating a vessel into which the mixed solution has been introduced with argon laser light. Since the apparatus and the photodetector for detecting Raman scattered light of dioxins generated by the laser irradiation are provided, the concentration of dioxins in the solution to be measured can be quickly measured.

[0033]

[0034]

[0035] According to the invention of wastewater treatment system of [Claim 8], in waste water treatment system for decomposing the harmful substances in waste water, analysis of dioxins concentration of dioxins in waste water measurable claim 3 It is equipped with a device and detects the dioxin concentration without time delay, and decomposes the dioxin in the wastewater in the presence of the hydroxyl radical according to the detected dioxin concentration, so that the dioxin and the like in the current raw water can be used. The decomposing ability of dioxins can be adjusted according to the situation of the content of harmful substances, and the raw water can be decomposed efficiently.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a dioxin analyzer according to the present embodiment.

FIG. 2 is a schematic diagram of a wastewater treatment system for decomposing harmful substances in wastewater.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 dioxin analyzer 11 silver colloid acetonitrile solution 12 solution to be measured 13 mixing means 14 mixed solution 15 cell 16 a laser light 16 laser device 17 Raman scattering light 18 photodetector 19 a amplifier 19 b A / D converter 19 c monitor 19 data processing means Reference Signs List 20 UV lamp 21 Ozone-containing gas 22 Dioxin decomposer 23 Coagulation tank 24 Floc forming tank 25 Coagulation sedimentation tank 26 Coagulation sedimentation treatment equipment 27 Wastewater containing harmful substances (raw water) 28 Coagulation sludge 29 Treated water

Continuation of the front page (56) References JP-A-11-33593 (JP, A) JP-A-7-108285 (JP, A) Eckhard Koglin, Combining HPTLC and Micro-Surface-Enhanced Raman Spectrocopy (Micro) SERS), Journal of Planar Chromatography, July 7, 1989, VOL. 2 / NO. 3, PAGE. 194-197 Clarkson, Molecular Recognition Using Surface-Enhanced Raman Scattering from Citrate-Reduced Silver Colloids, Journal of Japan, April 19, 2003. 22 / NO. 12, PAGE. 771-775 (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 21/62-21/74 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A solution to be measured is mixed with a metal colloid acetonitrile solution, the mixture is irradiated with an argon laser beam, and the dioxins in the mixture are subjected to Raman scattering,
A method for analyzing dioxins, comprising detecting the Raman scattered light and measuring the concentration of dioxins in the solution to be measured. 2. The method for analyzing dioxins according to claim 1, wherein the metal colloid is a silver colloid. 3. A mixing means for mixing a metal colloid acetonitrile solution with a solution to be measured, a laser device for irradiating an argon laser beam into a container into which the mixed solution has been introduced, and a Raman scattering of dioxins generated by the laser irradiation. A dioxin analyzer, comprising: a light detector for detecting light. 4. A wastewater treatment system for decomposing and processing harmful substances in wastewater, comprising the dioxin analyzer according to claim 3 capable of measuring the concentration of dioxins in wastewater, detecting the concentration of dioxins without time delay. A wastewater treatment system that decomposes dioxins in the wastewater in the presence of hydroxy radicals in accordance with the detected dioxin concentration.