JP2005227161A - Measuring instrument for measuring carbon component in water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extract CO<SB>2</SB>dissolved in sample water without using a gas-permeable film. <P>SOLUTION: A CO<SB>2</SB>extraction part 8 is so constituted that two quartz glass plates 14a and 14b are arranged so that the plane parts thereof are mutually opposed so as to leave an air layer and titanium oxide films 16a and 16b are respectively formed to the opposed plane parts as photocatalyst layers. The sample water issued from an oxidizing reaction part 6 flows along the surface of the titanium oxide layer 16a and ion exchange water flows along the surface of the titanium oxide layer 16b. The liquids flowing along the titanium oxide films 16a and 16b flow as thin liquid films by the catalytic action of titanium oxide and the giving and receiving of CO<SB>2</SB>is performed between the sample water and ion exchanged water. The sample water through the CO<SB>2</SB>extraction part 8 is discharged and the ion exchanged water is judged to a detection part 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a carbon component measuring apparatus such as a TOC (organic carbon) meter for evaluating pharmaceutical water, semiconductor manufacturing process water, cooling water, boiler water, tap water, etc., for example, there are few impurities such as pure water and ultrapure water. The present invention relates to a measuring apparatus suitable for use as an analyzer for evaluating organic contamination of water.

One method for measuring TOC is, for example, adding potassium peroxodisulfate to a sample solution and heating to convert the organic matter to CO _2, and then converting the sample solution into CO deionized water through a gas permeable membrane. ₂ is shifted to, to quantify the amount of CO ₂ from a change in the electrical conductivity of the deionized water, there is a method of determining the TOC value (see Patent Document 1.).

As a specific example, for example, a sample containing an organic compound is oxidized, and the difference between the electrical conductivity before oxidation and the electrical conductivity after oxidation of the sample is measured for electrical conductivity having at least two electrodes. By placing the cell in the pre-oxidation position and the post-oxidation position and detecting it using a differential conductivity meter that outputs the difference in the electrical conductivity of the sample between the positions of both conductivity measuring cells, There is a method of measuring the amount of increase in electrical conductivity caused by oxidative decomposition and quantifying the amount of TOC in the sample from the amount of increase in electrical conductivity (see Patent Document 2).
Japanese Patent No. 2510368 JP 2001-281189 A

In the method of extracting CO ₂ using a gas permeable membrane, extraction of CO ₂ takes a long time and the extraction efficiency is low.
Accordingly, an object of the present invention is to perform extraction of CO ₂ from sample water without using a gas permeable membrane.

The present invention includes a sample preparation section for converting carbon components of the sample water to extractable CO _2, and CO ₂ extractor for extracting CO ₂ water sample supplied from the sample adjustment section, taken out in a CO ₂ extractor The CO ₂ extraction unit is provided with a detecting unit for detecting CO ₂ , wherein the CO ₂ extracting unit is arranged such that two plate-like members face each other, and the surface of one plane part is The sample liquid flows as a liquid film, and pure water flows as a liquid film on the surface of the other flat surface. The distance between the two liquid films is a gas phase from the liquid film on the sample side to the liquid film on the pure water side. It is characterized in that it is set at a very small interval at which CO ₂ can move through
In the CO ₂ extraction unit of the present invention, the liquid film on the sample side and the liquid film on the pure water side face each other at a minute interval through the gas phase. The liquid film on the sample side is CO _{2 from} which the carbon component in the sample water can be extracted by the sample adjustment unit, and the CO ₂ in the sample liquid moves to the gas phase due to gas-liquid equilibrium at the interface. Since there is no CO _{2 in} the liquid film on the pure water side and it is neutral, CO ₂ in the gas phase easily moves to the liquid film in the pure water due to gas-liquid equilibrium at the gas-liquid interface on the pure water side. . In particular, when the sample preparation section includes an acidification section and the sample liquid film is acidic, the movement of CO ₂ from the liquid phase to the gas phase at the liquid film interface on the sample side is promoted.
The minute interval between the liquid film on the sample side and the liquid film on the pure water side means the interval at which the above-described CO ₂ movement occurs. Although the interval is convenient to move the narrow enough CO _2, the liquid film and the pure water side of the liquid film of the sample side must not close until the direct contact, the more the interval conversely becomes wide CO ₂ Since it remains in the gas phase and is difficult to move to the liquid film on the pure water side, the fine interval is suitably about 100 to 400 μm.

The surfaces of the two planar portions facing each other can be superhydrophilic or rough.
In that case, the superhydrophilic surface may have a photocatalytic layer formed thereon.
In order to enhance the action of the photocatalyst, it is preferable to provide a light source that emits light toward the photocatalyst layer. Thereby, the superhydrophilic action of the photocatalyst layer can be maintained, and the surface can be kept clean.

An example of the photocatalyst used in the present invention is titanium oxide (TiO ₂ ). The following points can be mentioned as the catalytic action of titanium oxide.
(1) Decomposition removal action of organic matter.
(2) Super-hydrophilic action that prevents water adhering to the object surface from forming a water droplet as a thin uniform film due to super-hydrophilicity.
By forming a titanium oxide film on the surface of the plate-like member by a method such as coating, the wettability of the plate-like member surface is enhanced by its superhydrophilic action, and the liquid flowing down on the surface of the plate-like member is uniformly thin It becomes a liquid film.
The rough surface is a surface processed into a porous or ground glass shape. For example, the surface of the glass plate can be obtained by processing by a sandblasting method or a chemical etching method.

The sample preparation unit of this apparatus includes an oxidation reaction unit or an acidification unit that oxidizes and decomposes organic carbon in the sample water to convert it into CO ₂ . TC (total carbon) measurement can be performed by converting all carbon components to CO ₂ in the oxidation reaction section, and IC measurement can be performed by converting IC (inorganic carbon) to an extractable state in the acidification section. In addition, after removing the IC after the acidification part, TOC measurement can be performed by converting the organic carbon to CO ₂ in the oxidation reaction part.

Since to extract the extraction method CO ₂ in the CO ₂ extracting section from the sample water flowing a liquid film through a vapor phase pure water flowing a liquid film, a gas permeable membrane extraction of CO ₂ This can be done without using it, and the CO ₂ extraction time can be shortened compared with the case where a gas permeable membrane is used.

[Example 1]
Hereinafter, an embodiment will be described in detail with reference to FIG.
FIG. 1 is a diagram schematically showing a configuration of an embodiment in which the present invention is applied to a TOC (total organic carbon) measuring apparatus.
From the upstream side (left side in the figure), a pH adjusting unit 2, an IC removing unit 4, an oxidation reaction unit 6, a CO ₂ extraction unit 8 and a detection unit 10 are arranged. The pH adjusting unit 2, the IC removing unit 4 and the oxidation reaction unit 6 constitute a sample adjusting unit.
For example, the pH adjuster 2 adjusts the pH of the sample water to be acidic by adding a certain proportion of an inorganic acid, for example, phosphoric acid, as a pH adjuster to the collected sample water.
The IC removing unit 4 is connected to the outlet channel of the pH adjusting unit 2. In the IC removing unit 4, the IC in the sample water is sucked through the gas permeable film 3 by reducing the pressure by the vacuum pump 5, for example, and the IC is removed from the sample water.
The oxidation reaction unit 6 is connected to the outlet channel of the IC removal unit 4, and potassium peroxodisulfate is used as an oxidizing agent for promoting the oxidation of organic substances in the sample water in the channel of the IC removal unit 4 and the oxidation reaction unit 6. Is added to the sample water. The oxidation reaction unit 6 includes a low-pressure mercury lamp 7 and a quartz glass tube 9 surrounding the low-pressure mercury lamp 7. By irradiating the sample water with ultraviolet rays generated from the low-pressure mercury lamp 7, the dissolved oxygen and the organic substance are reacted to convert the organic substance into CO ₂ .
The CO ₂ extraction unit 8 is arranged such that two quartz glass plates 14a and 14b, which are plate-like members, face each other across an air layer in a closed space as a gas phase, and an oxidation reaction The CO ₂ produced in the section 6 is extracted from the sample water and transferred to ion exchange water as pure water.

The surfaces of the quartz glass plates 14a and 14b are as shown in FIG. FIG. 2 (A) shows the surface of one quartz glass plate 14a. In the region 16a shown by hatching, the photocatalyst layers 16a and 16b are made of, for example, a titanium oxide film having a thickness of 0.1 μm to 0.5 μm. It is formed to a thickness and is super hydrophilic.
The region 16a has a wide central portion and is formed in a shape that is narrowed down to the center side in the vertical direction. A photocatalytic layer 16b having the same shape is also formed on the other quartz glass plate 14b.

As shown in FIG. 2B, the interval between the quartz glass plates 14a and 14b is adjusted so that the distance between the sample water flowing on the surface and the pure water is, for example, about 100 μm. This distance is adjusted by a spacer 30 made of PDMS (polydimethylsiloxane: silicone resin) provided between the two quartz glass plates 14a and 14b.
A through hole 22a is provided at the upper end of the region 16a. The hole 22a is connected to the oxidation reaction part 6, and guides the sample water from the oxidation reaction part 6 to the surface of the photocatalyst layer 16a. A through hole 22b is also provided at the lower end of the region 16a. The hole 22b is connected to the drain, and discharges the sample water to the outside from this flat portion. The other quartz glass plate 14b also has a through hole 23a at the upper end of the region 16b. The hole 23a guides ion exchange water to the surface of the photocatalyst layer 16b, and the through hole 23b provided at the lower end of the region 16b detects the hole. The ion exchange water that is connected to the unit 10 and has absorbed CO ₂ from the sample water is guided to the detection unit 10.
In the CO ₂ extraction unit 8, CO ₂ is exchanged between liquids flowing in a film shape on the surfaces of the titanium oxide films 16 a and 16 b facing each other. The CO ₂ dissolved in the sample water flowing on the surface of the titanium oxide film 16a is absorbed by the ion exchange water flowing on the surface of the titanium oxide film 16b through the air layer.

The detector 10 measures the conductivity and temperature of the ion-exchanged water that has absorbed CO ₂ by the CO ₂ extractor 8. Since the conductivity of ion-exchanged water is increased by dissolving CO ₂ in ion-exchanged water, the amount of CO ₂ contained in the sample water can be measured by measuring the conductivity of ion-exchanged water, The organic substance concentration contained in the sample water can be estimated. Moreover, since electrical conductivity is dependent on temperature, it correct | amends by measuring the temperature of ion-exchange water with electrical conductivity.
The ion-exchanged water whose conductivity and temperature are measured by the detector 10 is guided to the ion-exchange resin column 12 by the pump 11 to remove and deionize CO ₂ , and the ion-exchange resin column from the pump 11 by the circulation channel. The purity is increased by being sent to 12. The circulating ion exchange water is sent to the surface of the titanium oxide film 16b through the electromagnetic valve 13. The solenoid valve 13 is controlled in its opening / closing and opening degree by a control device (not shown) so that the flow rate of the ion exchange water can be adjusted.

Further, near the two quartz glass plates 14a and 14b of the CO ₂ extraction section 8, light sources 18a and 18b for irradiating the titanium oxide films 16a and 16b with ultraviolet light are provided, and the titanium oxide film 16a. Maintaining the superhydrophilic action of 16b and keeping its surface clean. Since the quartz glass plates 14a and 14b are transparent to the ultraviolet light generated from the light sources 18a and 18b, the quartz glass plates 14a and 14b are irradiated with ultraviolet light from the opposite side (back side) to the surface on which the titanium oxide films 16a and 16b are formed. However, the catalytic action of the titanium oxide films 16a and 16b can be enhanced and maintained.

The operation of this embodiment will be described below.
The sample introduced into the apparatus is first adjusted to an acidic pH by the pH adjusting unit 2, and then the IC is removed by the IC removing unit 4 and led to the oxidation reaction unit 6. Samples of the quartz glass tube 9 in the oxidation reaction unit 6, for example, the flow at a flow rate of 100 [mu] L / min, the organic matter contained in the sample is oxidized and decomposed by ultraviolet light having a wavelength of 185nm emitted by the low-pressure mercury lamp 7 CO ₂ It becomes.

Sample water through the oxidative decomposition unit 6 is guided to the CO ₂ extraction section 8, on the surface of the CO ₂ extracting section 8 of the quartz glass plate 14a titanium oxide film 16a formed on the surface of a liquid film form, for example, a thickness It flows down while maintaining 0.1 mm. On the other hand, ion-exchanged water flows down on the surface of the titanium oxide film 16b formed on the surface of the quartz glass plate 14b opposed to the quartz glass plate 14a, for example, while maintaining a film thickness of 0.1 mm. ing. The CO ₂ dissolved in the sample water flowing down on the surface of the titanium oxide film 16a moves to the ion exchange water through the gas phase.

The ion-exchanged water that has absorbed CO ₂ by the CO ₂ extraction unit 8 is guided to the detection unit 10 to measure the conductivity and temperature. The sample water that has passed through the CO ₂ extraction unit 8 is discharged.
Conductivity and temperature of the ion exchange water is pre-associated with the amount of CO ₂ absorbed in the ion exchange water, the amount of CO ₂ ion-exchanged water was absorbed by measuring the conductivity and temperature of the ion-exchanged water Can be measured, and thereby the organic substance concentration in the sample water can be estimated.
In this embodiment, when the vacuum pump 5 of the IC removing unit 4 is not operated, both IC and organic carbon are measured to become a TC meter. Further, when the vacuum pump 5 of the IC removing unit 4 is not operated and the lamp 7 is not turned on at the oxidation reaction unit 6, IC measurement is performed.
The shapes of the regions 16a and 16b are not limited to those shown in FIG.

[Example 2]
As a second embodiment, the two quartz glass plates 14a and 14b of the CO ₂ extraction section 8 are arranged on the surface of a plane portion facing the air layer in a closed space as a gas phase as shown in FIG. The thing which gave the process as shown can be mentioned.
In the CO ₂ extraction section 8 of this embodiment, the sample water and the ion exchange water are caused to flow down in the form of a liquid film by processing the groove 21 on the surface of the flat portion of the quartz glass plates 14a and 14b. .

FIG. 3A shows the surface of the flat portion of one of the quartz glass plates 14a. A rough surface portion 24 is provided at the center of the surface of the flat portion of the quartz glass plate 14a, and grooves 21a and 21b are provided above and below the rough surface portion 24. Is formed. The groove 21 a is branched into a large number of flow paths as one upstream flow path goes downstream, and is led to the rough surface portion 24. The groove 21b below the rough surface portion 24 is formed so as to be narrowed down toward the center side.
A through hole 22a is provided at the upper end of the groove 21a. The hole 22a is connected to the oxidation reaction unit 6 and guides the sample water from the oxidation reaction unit 6 to the groove 21a. A through hole 22b is provided at the lower end of the groove 21b. The hole 22b is connected to the drain, and discharges the sample water flowing down the groove 21b to the outside. The other quartz glass plate 14b is also provided with rough surface portions, grooves and through holes 23a and 23b having the same shape. The hole 23a guides the ion exchange water to the upper groove, and the through hole 23b provided at the lower end is connected to the detection unit 10 to guide the ion exchange water that has absorbed CO ₂ from the sample water to the detection unit 10.

The sample water coming out of the hole 22a is dispersed in a wide range by the groove 21a, and becomes a uniform liquid film in the surface of the rough surface portion 24. As shown in FIG. 3B, there is a gap between the sample water flowing down in the form of a liquid film at the rough surface portion 24 and the liquid film of ion-exchanged water formed in the permeation portion on the surface of the quartz glass plate 14b. CO ₂ is exchanged through the phases. The distance between the liquid film of the sample water and the liquid film of the ion exchange water is, for example, about 100 μm, and this distance is adjusted by the spacer 30 provided between the two quartz glass plates 14a and 14b. ing.

  As a processing method of the grooves 21a and 21b and the rough surface portion 24 on the surfaces of the quartz glass plates 14a and 14b, for example, sandblasting can be used. In sandblasting, a protective film (mask) is placed on the surface of the quartz glass plate to form grooves 21a and 21b, and openings are formed only on the rough surface portions (etching process). 21b, a rough surface is formed only on the rough surface portion.

As described above, the sample water and the ion-exchanged water flow down in the form of a liquid film respectively on the surfaces of the two plate-like members arranged opposite to each other, and exchange of CO ₂ between these two liquids. Thus, CO ₂ can be extracted without using a gas permeable membrane, and CO ₂ extraction efficiency can be improved.
Further, when the surfaces of the quartz glass plates 14a and 14b are processed into rough surfaces, the shapes of the grooves and rough surfaces to be processed may be other than those shown in FIG. 3, and the flowing liquid becomes a liquid film shape. It may be processed as follows.
The plate-like member is not limited to the quartz glass plate, but may be another glass plate or plastic.

In the embodiments, the TOC measuring apparatus according to the present invention has been described. However, the present invention is not limited to the TOC meter of FIG. 1 except for the total carbon meter except the IC removing unit 4 and the inorganic carbon meter excluding the oxidation reaction unit 6. It can also be applied to.
In addition to irradiating with ultraviolet rays, the oxidation reaction unit 6 may be, for example, one that adds potassium peroxodisulfate to a sample solution and heats it to convert organic matter into CO ₂ .

It is a figure which shows schematically the structure of one Example of the TOC meter to which this invention is applied. Is a diagram showing a CO ₂ extraction unit of the embodiment, (A) is a diagram showing the planar portion, (B) is a side view. It is a figure which shows the CO2 extraction part of a _2nd Example, (A) is a figure which shows a plane part, (B) is a side view.

Explanation of symbols

2 pH adjustment unit 3 Gas permeable membrane 4 IC removal unit 5 Vacuum pump 6 Oxidation reaction unit 7 Low pressure mercury lamp 8 CO ₂ extraction unit 9 Quartz glass tube 10 Detection unit 11 Pump 12 Ion exchange resin column 13 Electromagnetic valve 14a, 14b Quartz glass Plate 16a, 16b Titanium oxide film 18a, 18b Light source 21 Groove 22a, 22b, 23a, 23b Hole 24 Transmission part 30 Spacer

Claims (5)

A sample preparation section for converting carbon components of the sample water to extractable CO _2, and CO ₂ extractor for extracting CO ₂ water sample supplied from the sample preparation unit, taken out in the CO ₂ extracting unit CO _In the total organic carbon meter equipped with a detection unit for detecting ₂ ,
In the CO ₂ extraction section, two plate-like members are arranged so that the plane portions face each other, the sample liquid flows as a liquid film on the surface of the one plane portion, and on the surface of the other plane portion. The pure water flows as a liquid film, and the interval between the _two liquid films is set to a very small interval at which CO ₂ can move from the liquid film on the sample side to the liquid film on the pure water side via the gas phase. A measuring device for carbon components in water.   The apparatus for measuring a carbon component in water according to claim 1, wherein the surfaces of the two planar portions are superhydrophilic or rough. The apparatus for measuring a carbon component in water according to claim 2, wherein the superhydrophilic surface has a photocatalyst layer formed thereon. The CO ₂ extraction unit measuring apparatus in water carbon component according to claim 3 which includes a light source for irradiating light toward the photocatalyst layer. The sample preparation section of the water carbon component according to claim 1 comprising at least one of the oxidation reaction part and acidification unit for converting by oxidative decomposition of organic carbon in the sample water to CO ₂ measuring device.

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