JP2014071015A - Measurement instrument and measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique which allows easy measurement of a solute concentration in a suspension on site in a short measurement time.SOLUTION: A solute concentration measurement instrument 2 including a liquid absorbing material 1 and a solute concentration measurement part 3 linked with the liquid absorbing material 1 is used to measure a solute concentration in a suspension. The liquid absorbing material 1 is immersed in the suspension, and a liquid absorbed to the liquid absorbing material 1 is transferred to the solute concentration measurement part 3, and a solute concentration in the liquid is measured. It is preferable that the liquid absorbing material has water absorbency of 3 cm or more.

Description

  The present invention relates to a technique capable of easily measuring, for example, the concentration of a solute component in an aqueous suspension solution.

  A suspension, for example, an aqueous suspension, is an insoluble solid particle dispersed in a solution containing an aqueous solvent and a water-soluble solute. Examples of this type of suspension include muddy water, construction generated soil, cement slurry (fresh mortar or fresh concrete), mineral waste washing liquid, and the like. In general, very fine solid particles are dispersed in the suspension. Therefore, solid-liquid separation in the suspension is very difficult. However, solid-liquid separation is essential when the concentration of the solute in the suspension is required. As solid-liquid separation operations, for example, natural sedimentation (stationary), centrifugation, filtration and the like are known.

As an example in which the solute component in the suspension is measured, measurement of the content component in the soil can be mentioned. The concentration (salt concentration) of water-soluble components such as sodium chloride in the soil has a great influence on the crop yield. That is, when the salt concentration increases, the absorption of nutrients such as Ca and K is inhibited by Na ⁺ and Cl ⁻ . As a result, growth failure occurs and yield is reduced. For this reason, it is necessary to demineralize the soil in which seawater is flooded by high waves and tsunamis. In order to grasp exactly how much salt removal work is necessary, it is necessary to measure the salinity in the soil.

  As a technique for measuring the salinity of soil, the moisture content of undried dry soil that has been passed through a sieve with debris, etc., from the polluted soil (solid soil) to be investigated is weighed and weighed a certain amount of the soil. Add organic solvent to the mixture, shake by shaking for about 1 minute, let stand for about 30 minutes, centrifuge, use the filtrate filtered through a filter as the elution test solution, simple analysis method, ion electrode Technology for simple soil elution test for heavy metals, etc., characterized by quantitative measurement of heavy metals, etc. in liquids by the method, spectrophotometry, atomic absorption spectrometry, ICP emission spectrometry, or fluorescent X-ray analysis Japanese Patent Application Laid-Open No. 2005-331409 may be available.

  Or, “Powder collected from hardened concrete with a drill is mixed evenly and used as a sample. A certain amount is measured, and a certain amount of heated distilled water at 80 ° C or higher is added to elute chlorine ions for a certain period of time. Rapid measurement of chloride ion concentration in hardened concrete characterized by collecting water and measuring it using a portable salinometer such as a coulometric titration method having the same accuracy as the coulometric titration method shown in JIS A 1154 Method "" Powder collected from hardened concrete with a drill is mixed evenly to make a sample, weigh a certain amount, add a certain amount of room-temperature distilled water, heat to 80 ° C or more and elute chlorine ions for a certain period of time. The supernatant water was collected and measured using a portable salt meter such as a coulometric titration method having the same accuracy as the coulometric titration method shown in JIS A 1154 Might be able to utilize Rukoto the curing concrete, wherein the chloride ion concentration rapidly measuring method "technique (JP 2011-158437).

JP 2005-331409 A JP 2011-158437 A

  In the technique of Patent Document 1, the sample is left standing, centrifuged, and the filtrate filtered through a filter is used as a sample, and the chlorine concentration in the sample is measured with a predetermined analyzer.

  In the technique of Patent Document 2, after adding a certain amount of heated distilled water of 80 ° C. or more to a sample weighed and eluting chlorine ions for a certain period of time, the supernatant water is collected, or room temperature distilled water is used for the sample weighed. After adding a certain amount, the mixture is heated to 80 ° C. or more to elute chlorine ions for a certain period of time, and then the supernatant water is collected and the chlorine concentration in the supernatant water is measured with a predetermined analyzer.

  In any technique, it is essential that the sample (solution) to be applied to the analyzer is a liquid that is not turbid and does not contain solid particles.

  However, the suspensions of interest often contain fine particles such as clayey particles. It is difficult to easily obtain a clear supernatant from such a suspension in a short time. For example, in the technique of standing still, it takes a long time for the fine particles to settle. Therefore, a clear supernatant cannot be obtained from the suspension in a short time. When using a method other than stationary, such as centrifugation or filtration, an appropriate device is required. Therefore, in this case, it is difficult to carry out easily on site.

  Therefore, the problem to be solved by the present invention is to provide a technique that can easily measure the solute concentration in the suspension in the field and that requires only a short measurement time. For example, there is no need for operations such as centrifugation, and it is possible to quickly determine the solute concentration in the suspension using a simple instrument, and to provide a technology that does not cause a large error in the calculated solute concentration value. It is to be.

As studies for solving the above-mentioned problems have been intensively promoted, the present inventor has come to realize that the liquid sucked up from the suspension by capillary action has high transparency. Moreover, they have come to realize that the speed of suction by capillary action is very fast. Furthermore, it has been found that there is no great difference between the concentration of salt (Cl ⁻ etc.) contained in the liquid sucked up by capillary action and the concentration of salt (Cl ⁻ etc.) contained in the suspension. That is, when the salt (Cl ⁻ etc.) concentration contained in the liquid sucked up by capillary action is measured, this salt (Cl ⁻ etc.) concentration corresponds to the salt (Cl ⁻ etc.) concentration contained in the suspension. I found out.

  Based on the above findings, the present invention has been achieved.

That is, the problem is
An immersion process in which the liquid-absorbing material is immersed in the suspension;
It is solved by a method for measuring a solute concentration in a suspension, characterized in that it includes a measurement step in which the solute concentration contained in the liquid sucked up by the liquid absorbing material in the immersion step is measured.

  A method for measuring a solute concentration in a suspension, preferably, wherein the dipping step includes the liquid absorption of a solute concentration measurement apparatus including a liquid absorption material and a solute concentration measurement unit connected to the liquid absorption material. The material is immersed in a suspension, and the measurement step is a step in which the liquid sucked up by the liquid absorbent material is transferred to the solute concentration measuring unit and measured. It is solved by the method of measuring the solute concentration in the suspension.

  A solute concentration measuring method in the suspension, preferably, the liquid absorbing material has a water absorption of 3 cm or more according to a method based on JIS P 8141. It is solved by the measuring method.

A solute concentration measuring method of the suspension, preferably the suspension Cl ^- are solved by a solute concentration measurement method of suspension, characterized in that it contains.

  A method for measuring a solute concentration in a suspension, wherein the suspension preferably includes 3 to 30 parts by mass of insoluble fine particles having a particle size of 100 μm or less with respect to 100 parts by mass of a solvent component. This is solved by a method for measuring the solute concentration in the suspension.

  A method for measuring a solute concentration in the suspension, preferably, the measurement step is a detection paper piece impregnated with a detection component sensitive to a solute and exhibiting a specific color change or color development for each concentration of the solute, Alternatively, the problem is solved by a method for measuring a solute concentration in a suspension, which is performed using a detection medium carrying the detection component.

  A method for measuring the concentration of a solute in the suspension, preferably, the measuring step is carried by a detection paper piece impregnated with a detection component that changes color or develops color in response to the solute, or the detection component. This is solved by a method for measuring the solute concentration in a suspension, characterized in that the detection medium is used to determine the area ratio of the discolored or colored portion in the paper piece or the medium.

  For example, the solute concentration in a suspension containing fine particles such as soil can be easily measured in the field, and the measurement time is short. For example, operations such as centrifugation are unnecessary. Using a simple instrument, the solute concentration in the suspension can be determined quickly, and there is no significant deviation in the calculated solute concentration value. That is, the accuracy is quite high.

Plan view of the solute concentration measuring apparatus of the present invention Sectional view of the solute concentration measuring apparatus of the present invention Measuring method using the solute concentration measuring apparatus of the present invention

  The first invention is a solute concentration measuring apparatus. The solute concentration measuring apparatus includes a liquid absorbing material. The solute concentration measuring apparatus includes a solute concentration measuring unit. The liquid absorbing material and the solute concentration measuring unit are connected. Here, the connection includes the case where the solute concentration measuring unit is provided on one end side of the liquid-absorbing material (plate-like body). That is, the base of the solute concentration measuring unit may be the liquid absorbing material. In other words, it can also be said that the liquid-absorbing material (plate-like body) protrudes from the solute concentration measuring section.

  The liquid absorbing material is preferably a water absorbing material. Particularly preferably, the water absorption by a method based on JIS P 8141 is 3 cm or more. There is no particular restriction on the upper limit. If the value is large, the liquid absorption (water absorption) speed is high. Therefore, the measurement time is shortened accordingly. Currently, the upper limit of the water absorption is about 20 cm.

  The liquid absorbing material can be used in various forms, and is not particularly limited. For example, a plate-shaped body, a string-shaped body, etc. are mentioned. Here, the plate-like body is used in a concept including a sheet and a film. That is, the surface (side surface) in the thickness direction is smaller than the main surface (front surface, back surface) having a large area.

  The liquid absorbing material exhibits liquid absorbing properties. Therefore, basically, the surface is not covered with a water repellent or the like. Preferably, the main surface is not covered with a water repellent or the like. The liquid absorbency is manifested by capillary action.

  The liquid absorbing material is made of, for example, a fiber material. Those in which fine fibers are densely packed are preferable. For example, a sheet made of bundled fibers or meshed fibers is preferable. The fiber may be a long fiber or a short fiber. In the case of a sheet made of fibers aggregated in an indefinite direction, those made of short fibers are preferable. As a specific example, general paper such as Japanese paper or Western paper can be used in addition to filter paper. Quantitative filter paper and chromatographic filter paper having good water absorption are particularly preferred.

  The fiber is preferably a hydrophilic fiber. Examples thereof include cellulose, chemical fiber, glass fiber, and silica fiber. Of course, it is not limited to this.

  Various measuring devices can be used for the solute concentration measuring unit. The measuring device is not limited to a special one. The following measuring apparatus is preferable because it is simple. For example, the apparatus employs a colorimetric method that determines a density by comparing a color index corresponding to the density with a detected color. Alternatively, it is an apparatus that employs a method of calculating the concentration by measuring the area that has changed color by reacting with a certain amount of solution.

  The colorimetric method is used when the color developed by the reaction changes in density according to the solution concentration. Lambert-Beer's law is known as the color density that changes according to the density. The density is determined by comparison with a standard color corresponding to the density. Since the measurement accuracy is determined by the number of standard colors, it is semi-quantitative.

  In the method of measuring the area such as the color change area, the concentration is obtained by immersing a certain amount of test solution in a test paper and measuring the area that develops color by reaction. Because it measures by area, quantitative measurement with high accuracy is possible.

  A specific example of the measuring device is, for example, a detection paper piece which is impregnated with a detection component that is sensitive (for example, reacts) to a solute and exhibits a specific color change or color development for each concentration of the solute. Alternatively, it is a detection medium carrying the detection component.

  Alternatively, a detection paper piece impregnated with a detection component that is sensitive (for example, reacts) to a solute to exhibit discoloration or color development, or a detection medium carried by the detection component, the paper piece or the medium The area ratio of the discolored or colored portion is required.

  In addition, in order to measure the chlorine concentration in the suspension, the Mole method or the syringaldazine method is exemplified as a method of changing color or coloring in response to chlorine. In the measurement of, for example, hexavalent chromium concentration other than chlorine, 1,5-diphenylcarbonohydrazide (diphenylcarbazide) and the like are exemplified. Of course, it is not limited to this.

  More specifically, as a detection paper by the colorimetric method, Advantech test paper and Aqua Chemical (trade name) (registered trademark) manufactured by Nissan Chemical Industries, Ltd. may be mentioned. An example of calculating the concentration by area is Cantab (trade name) (registered trademark) sold by Taiheiyo Material Co., Ltd. Of course, it is not limited to these.

  The second invention is a method for measuring a solute concentration in a suspension. This method is a solute concentration measuring method using, for example, the solute concentration measuring apparatus of the first invention. The method includes a dipping process. This dipping step is a step in which the liquid absorbing material is dipped in the suspension. The dipping step is preferably a step in which the liquid absorbing material of a solute concentration measuring device including a liquid absorbing material and a solute concentration measuring unit connected to the liquid absorbing material is immersed in a suspension. The method comprises a measuring step. This measurement step is a step in which the solute concentration contained in the liquid sucked up by the liquid absorbing material in the immersion step is measured. The measurement step is preferably a step in which the liquid sucked up by the liquid absorbing material is transferred to the solute concentration measuring unit and measured.

The suspension (measuring object) contains, for example, fine particles insoluble in water, an aqueous solvent, and a solute that dissolves in the aqueous solvent. The fine particles are not limited as long as they do not substantially react with water. Specific examples include mineral powders such as clay, limestone, and silica, hydrated and cured particles of hydraulic substances (such as cement and gypsum), metal powders, and hard resin powders. The size of the fine particles is not particularly limited. However, it does not spontaneously settle in water or has a particle size such that the sedimentation rate is extremely slow. For example, a particle size equal to or less than silt to clayey soil particles in geotechnical engineering is applicable. The particle size is 100 μm or less (there is no particular restriction on the lower limit value). If it has only a larger particle size than this, solid-liquid separation by natural sedimentation is easy. The suspension has a solid concentration of 3 to 30 parts by mass of insoluble fine particles with respect to 100 parts by mass of the solvent. This is because if the amount of insoluble fine particles exceeds 30 parts by mass, liquid suction due to capillary action is reduced. The suspension is generally a colored liquid (colored liquid). For example, it is cloudy. For example, it is not colorless. For example, it is opaque or translucent. The suspension contains, for example, Cl ⁻ . For example, when the purpose is to examine salt damage (influence) of soil due to tsunami or seawater contamination, generally, Cl ⁻ contained in the suspension as a measurement target is the target. Of course, the measuring object is not limited to chlorine. It is appropriately selected as necessary.

  The liquid absorbing material is immersed in the suspension. For example, it is immersed from the front end side of the length of the liquid-absorbing material to a half region. As a result, the components of the suspension (for example, water and solute components such as chloride ions dissolved in water: fine particles that cause turbidity are removed) are increased by capillary action. . The ascending liquid is collected, and the collected liquid is applied to the solute concentration measuring unit (concentration detection medium or paper piece). Of course, when the solute concentration measurement unit (concentration detection medium or paper piece) is connected to the other end side (rear end side) of the liquid absorbing material (for example, the solute concentration measurement unit (concentration detection medium or paper piece). When the other end side (rear end side) of the liquid absorbing material is affixed to one end side), the liquid automatically moves (applies) to the solute concentration measurement unit. This gives the result.

  More specific description will be given below. It should be noted that the present invention is not limited in any way by the following examples.

  In the present embodiment, a solute concentration measuring device in which one end side of the water absorbent sheet is connected (attached) to one end side of a solute concentration measuring device (for example, the cantab or aqua check) is used.

  An example of this solute concentration measuring apparatus is shown in FIGS. 1 and 2, 1 is a water-absorbent sheet. The length of the water absorbent sheet 1 is, for example, 1 to 20 cm. 2 is a solute concentration measuring device. The solute concentration measuring unit 2 of the solute concentration measuring device 2 is bonded to one end side of the water absorbent sheet 1. When the water absorbent sheet 1 is immersed in the aqueous solution (suspension) 4 (see FIG. 3), the aqueous solution ascends the water absorbent sheet 1 due to capillary action of the water absorbent sheet 1. The aqueous solution that has moved up the water absorbent sheet 1 moves to the solute concentration measuring unit 3 side that is not immersed in the aqueous solution (suspension). This determines the solute concentration.

  The surface of the solute concentration measuring device 2 is covered with a water-impervious material. However, at least the tip side portion immersed in the aqueous solution (suspension) of the water absorbent sheet 1 is not covered with the water-impervious material. For example, if the entire area of the water-absorbent sheet 1 is covered with a water-impervious material, the water-absorbing action (capillary phenomenon) does not occur.

Hereinafter, it was examined that this example is suitable. The soil used in this example was a paddy soil having a high salinity due to salt damage, and the soil was clay. The water-soluble component was chloride ion (Cl ⁻ ) concentration.

  The detection paper (solute concentration measurement part) used is the product name “Aquacheck HC” of Nissan Chemical Industries, Ltd. as a colorimetric method, and the product name “Cantab (Low Concentration) ”was used. On the other hand, a titration method using an aqueous silver nitrate solution was used as an example of the prior art.

(Preparation of suspension)
100 g of dry soil sample and 500 g of distilled water are weighed and put into a 1000 ml stoppered plastic container, sealed with stopper, and this plastic container is shaken for about 2 hours with a shaker. It was.

[Titration method with silver nitrate aqueous solution]
The suspension was filtered through a membrane filter (pore size 0.45 μm), and the filtrate was collected to obtain a sample solution, which was placed in an automatic titrator (COM-1600, manufactured by Hiranuma Sangyo Co., Ltd.) and used as a titrant. Using a normal / L silver nitrate aqueous solution, the chlorine concentration was measured using the point at which the potential difference changed as a titration point, and the soil chlorine concentration was calculated from the ratio of soil and distilled water used for elution.

[How to use Aqua Check]
Aqua check was immersed in the sample solution for a predetermined time, the concentration was determined by a colorimetric table written on the bottle, and the soil chlorine concentration was calculated from the ratio of soil and distilled water used for elution.

[How to use Cantab]
Immerse the tip of the cantab in the sample solution and let it stand until the humidity indicator (solute concentration measuring part) turns dark blue. After changing the color, read the value of the discolored area and calculate the chlorine concentration using the conversion table. Soil chlorine concentration was calculated from the ratio of soil and distilled water used for elution.

[Installation of water absorbent sheet]
Various water-absorbing sheets (A4-A10 below) are cut into a length of 20 mm and a width of 5-10 mm, and are brought into close contact with the leading edge of the detection paper. The water-absorbing sheet was immersed in the suspension, and the measurement was carried out so that the water rising by the capillary phenomenon could be transferred to the test paper as it was.

(Measurement of water absorption)
The water absorption of various water absorbing sheets (A4 to A10 below) was measured. It conformed to the method of JIS P 8141. The tip of the water absorbent sheet was immersed in water, and the height rising after 10 minutes was measured.

Example 1
The water absorption of the water absorbent sheet was examined. The test results are shown in Table 1. A1 to A4 are comparative examples, and A4 to A9 are examples.

  In A1, the solution was filtered and then titrated with an aqueous silver nitrate solution. This is a conventional technique, and the chlorine concentration could be measured without problems.

  In A2 and A3, there is no water-absorbent sheet that is a feature of the present invention. In A2, an aqua check was used for the detection paper, and in A3, a cantab was used for the detection paper. In both cases, it was difficult to absorb water, the color could not be discriminated at A2, and the tip of the cantab was clogged at A3, and the color change could not be confirmed. As a result, the chlorine concentration could not be measured.

  In A4, a cantab was used after filter filtration without attaching a water absorbent sheet. Unlike A3, the chlorine concentration could be measured.

  In A5 and A6, quantitative filter paper No. 5A (manufactured by Toyo Filter Paper) was used as the water-absorbent sheet. The water absorption of the quantitative filter paper No. 5A was 9.5. In A5, an aqua check was used for the detection paper, and in A6, a cantab was used for the detection paper. In both cases, the function of the water-absorbent sheet was exhibited, and only the liquid content of the solid liquid rose due to the capillary phenomenon, and this liquid content transferred to the detection paper. As a result, discoloration could be confirmed and the chlorine concentration could be measured. The measurement results were also the same as in the prior art (A1), and it was confirmed that there was no problem in accuracy.

  In A7 to A9, a cantab was used as the detection paper. As the water-absorbent sheet, quantitative filter paper No. 3 (made by Toyo Roshi) is used for A7, chromatographic filter paper No. 50 (made by Toyo Roshi) is used for A8, and Kimwipe (trade name, made by Nippon Paper Crecia) (registered) for A9 Trademark) was used. The water absorption of the quantitative filter paper No. 3 was 7.5, the water absorption of the chromatographic filter paper No. 50 was 6, and the water absorption of Nippon Paper Kimwipe was 3.5. In both cases, the function of the water-absorbent sheet was demonstrated, discoloration could be confirmed, and the chlorine concentration could be measured. It was also confirmed that there was no problem in accuracy.

  That is, in the said Example, if the water absorption of the water absorbing sheet was 3 cm or more, it was confirmed that the function of the water absorbing sheet was exhibited. Therefore, the water absorption of the water absorbent sheet is preferably 3 cm or more. Of course, the present invention is not limited to this, and can be appropriately changed depending on the measurement object and various conditions.

(Example 2)
Using the soil sample used in Example 1, the suspension concentration was changed (B1 to B5), and the measurement range of the suspension concentration was examined. A quantitative filter paper No. 5A was used as the water-absorbent sheet, and a cantab was used as the detection paper (see A5 above). The test results are shown in Table 2.

  It was confirmed that the detection paper can be measured when the amount of the insoluble inorganic component (soil) is 30 parts by mass or less with respect to 100 parts by mass of the solvent (water) in the suspension. On the other hand, if the amount of the insoluble inorganic component is excessive, the absorption of the solvent from the filter paper is remarkably deteriorated, and the time required for the solvent to move to the detection paper is remarkably increased. Measurement is possible even with 1 part by mass of the insoluble inorganic component, but measurement without a water-absorbing sheet is possible because the suspension has transparency without using filter paper (water-absorbing sheet). .

  Therefore, the amount of insoluble fine particles is preferably 3 to 30 parts by mass with respect to 100 parts by mass of the solvent in the suspension.

1 Water Absorbent Sheet 2 Solute Concentration Measuring Device 3 Solute Concentration Measuring Unit 4 Aqueous Solution (Suspension)

Claims (7)

An immersion process in which the liquid-absorbing material is immersed in the suspension;
And a measuring step of measuring a solute concentration contained in the liquid sucked up by the liquid absorbing material in the dipping step. The dipping process includes
A step of immersing the liquid absorbing material in a suspension of a solute concentration measuring device comprising a liquid absorbing material and a solute concentration measuring unit connected to the liquid absorbing material;
The measurement step includes
2. The method for measuring a solute concentration in a suspension according to claim 1, wherein the liquid sucked up by the liquid absorbing material is transferred to the solute concentration measuring unit and measured. The method for measuring a solute concentration in a suspension according to claim 2, wherein the liquid absorbing material has a water absorption of 3 cm or more according to a method in accordance with JIS P 8141. The said suspension contains 3-30 mass parts of insoluble fine particles with a particle size of 100 micrometers or less with respect to 100 mass parts of solvent components, The solute concentration measurement in the suspension of Claims 1-3 characterized by the above-mentioned. Method. The suspension Cl ^- claims 1 to 4 either solute concentration measuring method in the suspension, characterized in that it contains. The measurement step includes
It is performed using a detection paper piece impregnated with a detection component that is sensitive to a solute and exhibits a specific color change or color development for each concentration of the solute, or a detection medium that carries the detection component. A method for measuring a solute concentration in a suspension according to any one of claims 1 to 5. The measurement step includes
A detection paper piece impregnated with a detection component that changes color or color in response to a solute, or a detection medium carrying the detection component is used, and the area of the color change or color development portion in the paper piece or the medium The method for measuring a solute concentration in a suspension according to any one of claims 1 to 5, wherein the quantification is performed by obtaining the ratio.

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