Device, hydroxide ion concentration measurement device provided with same, and hydroxide ion concentration measurement method using same

Abstract

The present invention addresses the problem of providing a device and a method for measuring the concentration of hydroxide ions, with which the concentration of hydroxide ions can be easily and quickly measured with high accuracy, and with which the measurement can be performed at a low cost. [Solution] The present invention has an insulating substrate, at least one insulating composite layer, and a liquid storage section capable of holding an ionic liquid, the insulating composite layer having a pair of electrodes and a semiconductor layer in contact with the pair of electrodes, and a layered composite hydroxide layer having an OH-ionic conductivity of 1 * 10-5 S / cm or more is provided between the insulating composite layer and the liquid storage section.

Description

Technical Field

[0001] The present invention relates to the ease of flow of electric current according to the hydroxide ion (OH - ) concentration, and more specifically, to measure the hydroxide ion (OH) concentration of the object to be measured based on the change in conductivity. - ) concentration measuring device and measuring method. Background Art

[0002] Hydroxide ion (OH - ) is one of the basic and important substances in various fields including material chemistry and life sciences. Without considering the existence and chemical behavior of hydroxide ions, it is impossible to understand chemical reactions, chemical equilibrium, and electrochemical phenomena.

[0003] As a method for measuring the concentration of such hydroxide ions, a pH titration method, a method using a pH meter, and the like are conventionally known.

[0004] Furthermore, Patent Document 1 discloses separating hydroxide ions in a solution by chromatography and measuring the hydroxide ion concentration by using an electrical conductivity method or a light absorption method.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2002-5916 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The pH titration method can measure the hydroxide ion concentration with high accuracy, but accurate titration requires proficiency, and therefore cannot be measured easily and accurately.

[0010] The pH meter measures the hydrogen ion concentration by the potential difference between the glass electrode and the reference electrode, and the hydroxide ion concentration can be measured based on this value. Although the measurement can be performed easily and quickly, the accuracy is not high.

[0011] In addition, although the method of separating hydroxide ions using chromatography disclosed in Patent Document 1 has high measurement accuracy, it has the following problems: a separation column must be prepared and selected according to the type of solvent and pH range. In addition, the separation column is prone to cracking and requires attention in operation. Chromatography is expensive and cannot be easily measured.

[0012] In view of the above-mentioned situation, an object of the present invention is to provide a device and a method for measuring hydroxide ion concentration, which can measure hydroxide ion concentration with high accuracy, easily and quickly, and can measure at a relatively low cost.

[0013] Another object of the present invention is to provide a device whose electrical conductivity changes according to the hydroxide ion concentration, which can be used in the above-mentioned measuring apparatus and method for measuring the hydroxide ion concentration.

[0014] Means used to solve problems

[0015] The present invention is invented to solve the above-mentioned problems in the prior art, and the device of the present invention, a hydroxide ion concentration measuring apparatus including the device, and a hydroxide ion concentration measuring method using the device include the following inventions.

[0016] [1] A device comprising an insulating substrate, at least one insulating composite layer, and a liquid storage portion capable of holding an ionic liquid,

[0017] The insulating composite layer comprises a pair of electrodes and a semiconductor layer in contact with the pair of electrodes.

[0018] The device has an OH between the aforementioned insulating composite layer and the aforementioned liquid storage part. - The ionic conductivity is 1×10 -5 S / cm or more layered double hydroxide layer.

[0019] [2] The device according to [1], wherein the insulating composite layer further comprises a third electrode,

[0020] Furthermore, the device includes an insulating layer between the pair of electrodes and the semiconductor layer and the third electrode.

[0021] [3] The device according to [1] or [2], wherein the field effect mobility of the semiconductor layer is 20 cm 2 / Vs or above.

[0022] [4] The device according to any one of [1] to [3], wherein the semiconductor layer contains at least one of oxygen, sulfur, nitrogen, boron, or carbon.

[0023] [5] The device according to [4], wherein the semiconductor layer contains at least one of indium, zinc, tin, or a Group 13 element.

[0024] [6] The device according to any one of [1] to [5], wherein the semiconductor layer comprises at least one of graphene, carbon nanotubes, boron nitride, metal dichalcogenide, or phosphorene.

[0025] [7] The device according to any one of [1] to [6], wherein the layered double hydroxide layer comprises pyreneboric acid, 1-pyrenebutyric acid N-hydroxysuccinimide ester or a compound of the general formula [MII 1-x M' III x (OH) 2 ] x+ At least any one of the hydroxides of

[0026] General formula [M II 1-x M' III x (OH) 2 ] x+ In, M II Selected from Ca 2+ Mg 2+ , Mn 2+ , Fe 2+ 、Co 2+ 、Ni 2+ , Cu 2+ 、Zn 2+ and 2Li + The group composed of M III Selected by Al 3+ , Mn 3+ , Fe 3+ 、Co 3+ Cr 3+ and Ni 3+ Composed of groups.

[0027] [8] The device according to any one of [1] to [7], wherein a protective layer is provided between the layered double hydroxide layer and the semiconductor layer.

[0028] [9] The device according to any one of [1] to [8], wherein the thickness of the semiconductor layer is 0.5 μm or less.

[0029]

[10] The device according to any one of [1] to [9], wherein a maximum height Sz of a surface of the semiconductor layer on the layered double hydroxide layer side is 0.05 μm or less.

[0030]

[11] The device according to any one of [1] to

[10] , wherein an arithmetic mean height Sa of a surface of the semiconductor layer on the layered double hydroxide layer side is 0.03 μm or less.

[0031]

[12] A device for measuring hydroxide ion concentration, comprising the apparatus described in any one of [1] to

[11] .

[0032]

[13] A method for measuring hydroxide ion concentration, using the apparatus described in any one of [1] to

[11] .

[0033]

[14] The method for measuring the hydroxide ion concentration according to

[13] , wherein the hydroxide ion concentration of any one of river water, sea water, clean water, washing water or factory wastewater is measured.

[0034] Effects of the Invention

[0035] According to the present invention, the conductivity can be determined according to the hydroxide ion (OH - ) concentration in a solution as the test object with high accuracy, ease and rapidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram for explaining the configuration of the hydroxide ion concentration measuring device according to the present embodiment.

[0037] Figure 2 This is a schematic diagram for explaining the structure of a hydroxide ion concentration measuring device according to another embodiment. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments (examples) of the present invention will be described in more detail based on the drawings.

[0039] It should be noted that the hydroxide ion concentration measuring device and measuring method of the present invention can measure the hydroxide ion concentration of ion-containing liquids as the test objects, such as river water, sea water, clean water, washing water or factory wastewater, etc., for example, making it possible to continuously monitor the quality of these waters, and can also contribute to the universal and equal acquisition of safe and cheap drinking water.

[0040] Figure 1 This is a schematic diagram for explaining the configuration of the hydroxide ion concentration measuring device according to the present embodiment.

[0041] like Figure 1 As shown, the hydroxide ion concentration measuring device 50 of this embodiment includes a device 10, and the device 10 has an insulating substrate 12, at least one insulating composite layer 14, and a liquid storage portion 16 capable of holding an ion-containing liquid. It should be noted that the device 10 constructed as follows can also be made into a semiconductor element such as a field effect transistor (FET) or a metal oxide semiconductor field effect transistor (MOSFET).

[0042] The insulating substrate 12 is a substrate formed of a material having insulating properties, such as glass or ceramics.

[0043] The insulating composite layer 14 includes a pair of electrodes (a first electrode 141 and a second electrode 142 ) and a semiconductor layer 144 in contact with the pair of electrodes 141 and 142 .

[0044] In addition, a layered double hydroxide layer 18 is provided between the insulating composite layer 14 and the liquid storage portion 16. The layered double hydroxide layer 18 is in contact with the ion-containing liquid L held by the liquid storage portion 16, and conducts hydroxide ions (OH - ). The OH of the layered double hydroxide layer 18 in this embodiment - The ionic conductivity is 1×10 -5 S / cm or more, more preferably 1×10 -4 S / cm or more, more preferably 5.0×10 -4 S / cm or more, most preferably 1×10 -3 S / cm or more. It should be noted that the OH of the layered double hydroxide layer 18 is - The upper limit of ion conductivity is not particularly specified, but is generally 1.0×10 S / cm.

[0045] Furthermore, a protective layer 20 is provided between the layered double hydroxide layer 18 and the semiconductor layer 144 , and the layered double hydroxide layer 18 and the electrodes 141 and 142 are electrically insulated by, for example, the partition 16 a of the liquid storage unit 16 .

[0046] In addition, the layered double hydroxide layer 18 preferably contains at least one of the following: pyreneboric acid, 1-pyrenebutyric acid N-hydroxysuccinimide ester, or

[0047] The general formula of the layered double hydroxide layer 18 is [M II 1-x M' III x (OH) 2 ] x+ And M II Selected from Ca 2+ Mg 2+ , Mn 2+ , Fe 2 + 、Co 2+ 、Ni 2+ , Cu 2+ 、Zn 2+ and 2Li + The group composed of M III Selected by Al 3+ , Mn 3+ , Fe 3+ 、Co 3+ Cr 3+ and Ni 3+ Composed of the group of hydroxides.

[0048] In addition, the semiconductor layer 144 preferably has a field effect mobility of 20 cm 2 / Vs or more, more preferably 60cm2 / Vs or above.

[0049] The semiconductor layer 144 may contain at least one of oxygen, sulfur, nitrogen, boron, or carbon. In addition, the semiconductor layer 144 preferably further contains at least one of indium, zinc, tin, or a Group 13 element.

[0050] Such a semiconductor layer 144 may include at least one of graphene, carbon nanotubes, boron nitride, metal dichalcogenide, and phosphorene.

[0051] More specifically, for example, IZO (Indium-Zinc-Oxide) such as Ta-IZO can be used as the semiconductor layer 144 .

[0052] In addition, as for the thickness of the semiconductor layer 144, the thinner the thickness, the greater the change in the conductivity of the surface layer, so the change in the charge that migrates as described later increases, and the measurement accuracy is improved. The thickness of the semiconductor layer 144 is preferably 0.5 μm or less, more preferably 0.1 μm or less, and particularly preferably 0.05 μm or less. It should be noted that the lower limit of the thickness of the semiconductor layer 144 is not particularly specified, and is generally 0.005 μm or more.

[0053] In addition, the surface 144a on the layered double hydroxide layer 18 side of the semiconductor layer 144 is preferably as smooth as possible. In the case where the surface 144a of the semiconductor layer 144 is not smooth, for example, a gap may be generated between the semiconductor layer 144 and the protective layer 20, or the protective layer 20 may not be formed continuously, or the adhesion between the semiconductor layer 144 and the layered double hydroxide layer 18 may be reduced, and the current may flow only in a part of the surface 144a of the semiconductor layer 144. Therefore, the measurement accuracy may be reduced, or the operation may become unstable.

[0054] Specifically, the maximum height Sz of the surface 144a of the semiconductor layer 144 is preferably 0.05 μm or less, more preferably 0.01 μm or less, and most preferably 0.003 μm or less. The lower limit of the maximum height Sz is not particularly specified, but is generally 0.0005 μm or more. In addition, the arithmetic mean height Sa of the surface 144a on the layered double hydroxide layer 18 side of the semiconductor layer 144 is preferably 0.03 μm or less, more preferably 0.005 μm or less, and most preferably 0.002 μm or less. The lower limit of the arithmetic mean height Sa is not particularly specified, but is generally 0.0002 μm or more.

[0055] Here, the maximum height Sz and the arithmetic mean height Sa are parameters of surface roughness specified in ISO 25178, and such parameters can be measured, for example, by a 3D surface roughness profile measuring instrument (NexView manufactured by ZYGO Corporation). In this case, the measurement conditions are preferably as follows.

[0056] According to ISO25178, the measurement was performed under the conditions of 50x objective lens, 20x zoom lens, and 89μm×87μm measurement range. A roughness curve with a range of 3μm×3μm was extracted from the obtained three-dimensional surface shape, and the roughness curve was corrected according to the following correction conditions using the analysis program "Mx" attached to the 3D surface roughness shape measuring instrument to calculate the maximum height Sz and the arithmetic mean height Sa.

[0057] <Calibration conditions>

[0058] -Remove: Form Remove

[0059] -Filter Type: Spline

[0060] -Filter: Low Pass

[0061] -Type: Gaussian Spline Auto

[0062] In addition, the protective layer 20 is provided to protect the semiconductor layer 144 from contacting the ion-containing liquid L. By providing the protective layer 20, the semiconductor layer 144 can be prevented from being corroded, and the durability and reliability of the semiconductor layer 144 can be improved. As the material of the protective layer 20, any known material can be used as long as it has insulating properties, and a material with corrosion resistance is preferred. For example, Ta 2 O 5 、Si 3 N 4 、SiO 2 The thickness is preferably 0.01 μm or more and 0.5 μm or less, and more preferably 0.03 μm or more and 0.2 μm or less.

[0063] In addition, in the present embodiment, the insulating composite layer 14 further includes a third electrode 143. With this configuration, by applying a voltage from the third electrode 143, the current flowing between the first electrode 141 and the second electrode 142 increases, and the measurement accuracy can be improved. In addition, the pair of electrodes 141, 142 and the semiconductor layer 144 include an insulating layer 145 between the third electrode 143. As the material of the insulating layer 145, as long as it can perform electrical insulation, a known material can be applied, for example, various ceramics, resins, etc. can be used, and the thickness is preferably 0.01 μm or more and 0.5 μm or less, and more preferably 0.03 μm or more and 0.2 μm or less.

[0064] In addition, the measuring device 50 of the present embodiment includes a variable voltage source 32 for applying a voltage between the first electrode 141 and the second electrode 142, a variable voltage source 34 for applying a voltage between the first electrode 141 and the third electrode 143, an ammeter 36 for measuring the current value between the first electrode 141 and the second electrode 142, and a voltmeter 38 for measuring the voltage value between the first electrode 141 and the third electrode 143.

[0065] In the device 10 of the present embodiment configured as above, the OH containing ionic liquid L held in the liquid storage section 16 is - The ion concentration changes the ease with which current flows in the semiconductor layer 144. Specifically, the OH of the conductive layered double hydroxide layer 18 changes. - The larger the amount of , the easier it is for current to flow in the semiconductor layer 144 .

[0066] Therefore, in the measuring device 50 of the present embodiment, in a state where the ion-containing liquid L as the analyte is stored in the liquid storage section 16, a predetermined voltage, for example, a voltage of about 1V to 10V is applied between the first electrode 141 and the second electrode 142 by the variable voltage source 32, and the voltage applied between the first electrode 141 and the third electrode 143 is gradually increased by the variable voltage source 34. When the current flowing between the first electrode 141 and the second electrode 142 measured by the ammeter 36 reaches a predetermined current value, the voltage value (V TH ).

[0067] By targeting OH - The ion concentration of the ionic liquid L is known and the voltage value V is prepared in advance. TH The standard curve of the corresponding relationship can be used to determine OH - The ion concentration of the ionic liquid L is unknown, that is, the OH of the substance being measured. - Ion concentration.

[0068] In addition, the measuring device 50 of the present embodiment can measure the current value (I ) of the current flowing between the first electrode 141 and the second electrode 142, that is, in the semiconductor layer 144, by the ammeter 36 when a predetermined voltage, for example, a voltage of about 1 V, is applied between the first electrode 141 and the second electrode 142 by the variable voltage source 32 in a state where the ion-containing liquid L as the analyte is stored in the liquid storage section 16. DS ).

[0069] By pre-setting the current value I DS With OH - A standard curve containing ionic liquid L with known ion concentration can be used to determine OH - OH containing ionic liquid L as the analyte with unknown ion concentration - Ion concentration.

[0070] Figure 2 This is a schematic diagram for explaining the structure of a hydroxide ion concentration measuring device according to another embodiment.

[0071] Figure 2 The hydroxide ion concentration measuring device 50 shown is basically the same as Figure 1 The hydroxide ion concentration measuring device 50 shown has the same configuration, and the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

[0072] In the hydroxide ion concentration measuring apparatus 50 of the present embodiment, the device 10 does not include the third electrode 143 and the insulating layer 145 .

[0073] In the case of this configuration, when the liquid storage section 16 stores the ion-containing liquid L as the sample, a voltage V smaller than the above voltage value V is applied between the first electrode 141 and the second electrode 142 by the variable voltage source 32. TH Under the condition of a predetermined voltage, the current value (I DS ), using the current value I DS With OH - A standard curve containing ionic liquid L with known ion concentration can be used to determine OH - OH containing ionic liquid L as the analyte with unknown ion concentration - Ion concentration.

[0074] As mentioned above, although the preferred embodiment of the present invention was described, the present invention is not limited thereto, and various modifications can be made within the scope not departing from the purpose of the present invention.

[0075] Explanation of symbols

[0076] 10. Equipment

[0077] 12 Insulation substrate

[0078] 14 Insulation composite layer

[0079] 141 1st electrode

[0080] 142 2nd electrode

[0081] 143 3rd electrode

[0082] 144 Semiconductor layer

[0083] 144a Surface

[0084] 145 Insulation layer

[0085] 16 Liquid storage part

[0086] 16a Divider

[0087] 18 Layered double hydroxide layer

[0088] 20 protective layer

[0089] 32 Variable voltage source

[0090] 34 Variable voltage source

[0091] 36 Ammeter

[0092] 38 Voltmeter

[0093] 50 Measurement device

[0094] L containing ionic liquid

Claims

1. A device comprising an insulating substrate, at least one insulating composite layer, and a liquid storage portion capable of holding an ionic liquid, The insulating composite layer has a pair of electrodes and a semiconductor layer in contact with the pair of electrodes. The device has an OH layer between the insulating composite layer and the liquid storage part. - The ionic conductivity is 1×10 -5 S / cm or more layered double hydroxide layer.

2. The device according to claim 1, wherein: The insulating composite layer further comprises a third electrode. Furthermore, the device includes an insulating layer between the pair of electrodes and the semiconductor layer and the third electrode.

3. The device according to claim 1, wherein: The field effect mobility of the semiconductor layer is 20 cm 2 / Vs or above.

4. The device according to claim 1, wherein: The semiconductor layer contains at least any one of oxygen, sulfur, nitrogen, boron or carbon.

5. The device according to claim 4, wherein: The semiconductor layer includes at least any one of indium, zinc, tin, or a Group 13 element.

6. The device according to claim 4, wherein: The semiconductor layer includes at least any one of graphene, carbon nanotubes, boron nitride, metal dichalcogenide, or phosphorene.

7. The device according to claim 1, wherein: The layered double hydroxide layer comprises pyrene boric acid, 1-pyrene butyric acid N-hydroxysuccinimide ester or a general formula of [M II 1-x M' III x (OH)2] x+ At least any one of the hydroxides of General formula [M II 1-x M' III x (OH)2] x+ In, M II Selected from Ca 2+ Mg 2+ , Mn 2+ , Fe 2+ 、Co 2+ 、Ni 2+ , Cu 2+ 、Zn 2+ and 2Li + The group composed of M' III Selected by Al 3+ , Mn 3+ , Fe 3+ 、Co 3+ Cr 3+ and Ni 3+ The group composed of.

8. The device according to claim 1, wherein: A protective layer is provided between the layered double hydroxide layer and the semiconductor layer.

9. The device according to claim 1, wherein: The semiconductor layer has a thickness of 0.5 μm or less.

10. The device according to claim 1, wherein: The maximum height Sz of the surface of the semiconductor layer on the layered double hydroxide layer side is 0.05 μm or less.

11. The device according to claim 1, wherein: An arithmetic mean height Sa of the surface of the semiconductor layer on the layered double hydroxide layer side is 0.03 μm or less. 12 . A device for measuring hydroxide ion concentration, comprising the apparatus according to claim 1 .

13. A method for measuring hydroxide ion concentration, using the device according to any one of claims 1 to 11. 14 . The method for measuring the hydroxide ion concentration according to claim 13 , wherein the hydroxide ion concentration of any one of river water, sea water, clean water, washing water or factory wastewater is measured.

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