Preparation method of a chlorine ion selective polymer membrane

Abstract

This application belongs to the technical field of ion-selective electrodes, and specifically relates to a preparation method of a chloride ion-selective polymer membrane. The chloride ion-selective polymer membrane includes a chloride ion carrier, a high molecular polymer, a plasticizer, and an ion localizer. The ratio of the chloride ion carrier, the high molecular polymer, the plasticizer, and the ion localizer is 1-8:100-150:200-300:0.1-2. The chloride ion carrier is 4,5-dimethyl-3,6-dioctyloxy-o-phenylene-bis(mercuric trifluoroacetate), the high molecular polymer is polyvinyl chloride, the plasticizer is di-n-octyl sebacate, and the ion localizer is dodecylammonium chloride. When preparing, the ion localizer dodecylammonium chloride is added, so that the prepared chloride ion-selective polymer membrane is not interfered by other anions when detecting chloride ions.

Description

Technical Field

[0001] This application belongs to the technical field of ion-selective electrodes, and specifically relates to a preparation method of a chloride ion-selective polymer membrane. Background Art

[0002] Ion-selective polymer membranes are a type of electrochemical sensor that uses membrane potential to measure the activity or concentration of ions in a solution. When it comes into contact with a solution of the ion to be measured, a membrane potential directly related to the activity of the ion is generated at the interface between its sensitive membrane and the solution. Ion-selective electrodes, also known as membrane electrodes, have a special electrode membrane. The electrode membrane has a selective response to specific ions, and the relationship between the potential of the electrode membrane and the content of the ion to be measured conforms to the Nernst equation.

[0003] Water is the source of life. For water safety, it is necessary to detect the concentration of various ions in water, especially the concentration of chloride ions. However, the existing preparation methods of ion-selective membranes are complex and have poor selectivity. Summary of the Invention

[0004] In order to solve the problems of the existing technology, this application provides a preparation method of a chloride ion-selective polymer membrane, and this application is achieved through the following scheme:

[0005] A chloride ion-selective polymer membrane includes a chloride ion carrier, a high molecular polymer, a plasticizer, and an ion localizer. The ratio of the chloride ion carrier, high molecular polymer, plasticizer, and ion localizer is 1-8:100-150:200-300:0.1-2. The chloride ion carrier is 4,5-dimethyl-3,6-dioctyloxy-o-phenylene-bis(mercuric trifluoroacetate), the high molecular polymer is polyvinyl chloride, the plasticizer is di-n-octyl sebacate, and the ion localizer is dodecylammonium chloride.

[0006] A preparation method of a chloride ion-selective polymer membrane, the preparation steps are as follows: S1 Mix the chloride ion carrier, high molecular polymer, plasticizer, ion localizer, and solvent evenly, and stir at a speed of 400-1000 rpm for 2-5 hours to obtain a clear and transparent solution; S2 Place the glass plate on a horizontal workbench, place it in a fume hood, and use a wet film coater to coat the solution obtained in step S1 on the glass plate to obtain a wet film, and the coating thickness is 50μm or 100μm or 150μm or 200μm; S3 Let the wet film dry naturally at 20-25°C for 2-5 hours, and then place the glass plate in a vacuum drying oven and dry it at 20-25°C for 8-12 hours to obtain a polymer membrane; S4 Dissolve the chloride salt in water to prepare a salt solution with a chloride ion concentration of 100μM-100mM, then immerse the polymer membrane in the salt solution for 12-36 hours, and then wash it clean with a large amount of ultrapure water to complete the preparation of the membrane sheet; S5 Cut the membrane sheet and assemble it into a double salt bridge ion-selective electrode.

[0007] Further, the solvent is tetrahydrofuran or cyclohexanone; the chloride salt is one or more of sodium chloride, potassium chloride, magnesium chloride, ferric chloride, and ferrous chloride.

[0008] Furthermore, the mass ratio of the solvent to the sum of the chloride ion carrier, the polymer, the plasticizer, and the ion localizer is 10 - 20 mL: 1 - 3 g.

[0009] Furthermore, the 4,5 - dimethyl - 3,6 - dioctyloxy - o - phenylenebis(mercuric trifluoroacetate) can be replaced by manganese(III) meso - tetraphenylporphine chloride or 3,6 - didodecyloxy - 4,5 - dimethyl - o - phenylenebis(mercuric chloride).

[0010] Furthermore, the polyvinyl chloride can be replaced by polymethyl methacrylate.

[0011] Furthermore, the dioctyl sebacate can be replaced by o - nitrophenyl octyl ether or / and dibutyl phthalate.

[0012] Furthermore, the dodecylammonium chloride can be replaced by one or more of potassium tetrakis(4 - chlorophenyl)borate, tetraoctylammonium chloride, and sodium tetrakis(3,5 - bis(trifluoromethyl)phenyl)borate; a porous ceramic core is provided on one side of the double - salt - bridge ion - selective electrode.

[0013] Furthermore, the double - salt - bridge ion - selective electrode includes a silver / silver chloride reference electrode, a thermistor, and a silver / silver chloride reference electrode wire. A chloride - ion - selective polymer membrane is provided at the bottom of the double - salt - bridge ion - selective electrode. An internal filling solution is provided above the ion - selective polymer membrane. A salt bridge is provided above the internal filling solution. The bottoms of the silver / silver chloride reference electrode and the thermistor are inserted into the salt bridge, and the bottom of the silver / silver chloride reference electrode wire is inserted into the internal filling solution.

[0014] Furthermore, the silver / silver chloride reference electrode includes a left glass tube and a silver / silver chloride reference electrode wire located inside the left glass tube. An internal reference solution is provided inside the left glass tube. A porous ceramic core is provided at the bottom of the left glass tube. The thermistor includes a right glass tube and a thermistor lead located inside the right glass tube. A thermistor is provided at the bottom of the thermistor lead. Thermal conductive silicone grease is provided at the bottom of the right glass tube.

[0015] Furthermore, the internal reference solution is a 3 mol / L potassium chloride solution; the internal filling solution is a 10 -3 - 10 -1 mol / L chloride - ion solution; a porous ceramic core is provided on one side of the double - salt - bridge ion - selective electrode. The setting of the porous ceramic core can realize the ion exchange between the electrode and the external solution.

[0016] Beneficial effects: (1) When preparing, adding the ionic localizer dodecyl ammonium chloride makes the prepared chloride ion selective polymerization membrane not interfered by other anions when detecting chloride ions; (2) The chloride ion selective polymerization membrane prepared by this application has high stability and high sensitivity; (3) By soaking the polymerization membrane in a salt solution for 12 - 36 hours, the activity of the polymerization membrane is increased; (4) The preparation method of the application is simple and the operation is simple, without the need to add various masking agents and indicators, greatly reducing the consumption of reagents. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some preferred embodiments of the present application, rather than all embodiments. For the preferred embodiments of the present application, for those of ordinary skill in the art, without creative efforts, other embodiments and drawings can be obtained based on these embodiments and drawings, all of which belong to the protection scope of the present application.

[0018] Figure 1 It is the working principle diagram of the polymerization membrane in the embodiment of the present application;

[0019] Figure 2 It is the structural schematic diagram of the double salt bridge ion selective electrode in the embodiment of the present application;

[0020] In the figure, 1, silver / silver chloride reference electrode; 2, thermistor element; 3, silver / silver chloride reference electrode wire; 4, chloride ion selective polymerization membrane; 5, internal filling solution; 6, salt bridge; 7, internal reference solution; 8, porous ceramic core; 9, right glass tube; 10, thermistor lead; 11, thermistor; 12, thermal conductive silicone grease. Embodiment Modes

[0021] To make the objectives, technical solutions, and advantages of the present application clearer, the following will further describe the embodiment modes of the present application in detail. It should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. The above definitions are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the structure referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. Example 1

[0022] A preparation method of a chloride ion selective polymer membrane, comprising the following components: a chloride ion carrier, a polymer, a plasticizer, and an ion localizer. The chloride ion carrier is 4,5-dimethyl-3,6-dioctyloxy-o-phenylene-bis(mercuric trifluoroacetate), the polymer is polyvinyl chloride, the plasticizer is dioctyl sebacate, and the ion localizer is dodecylammonium chloride;

[0023] The preparation steps are as follows: S1 Mix 2 mg of 4,5-dimethyl-3,6-dioctyloxy-o-phenylene-bis(mercuric trifluoroacetate), 0.5 mg of dodecylammonium chloride, 66 mg of polyvinyl chloride, 132 mg of dioctyl sebacate, and the solvent cyclohexanone evenly, and stir at a speed of 400 - 1000 rpm for 2 - 5 hours to obtain a clear and transparent solution; S2 Place the glass plate on a horizontal workbench, place it in a fume hood, and use a wet film coater to coat the solution obtained in step S1 on the glass plate to obtain a wet film, with a coating thickness of 100 μm; S3 Air-dry the wet film naturally at 20 - 25 °C for 4.5 hours, and then place the glass plate in a vacuum drying oven and dry it at 20 - 25 °C for 11 hours to obtain a polymer membrane; S4 Dissolve the chloride salt in water to prepare a salt solution with a chloride ion concentration of 60 mM, then immerse the polymer membrane in the salt solution for 33 hours, and then wash it clean with a large amount of ultrapure water to complete the preparation of the membrane sheet; S5 Cut the membrane sheet and assemble it into a double salt bridge ion selective electrode for testing, and the test data is shown in Table 1 below;

[0024] Furthermore, the addition amount of the solvent cyclohexanone is 1.5 ml;

[0025] Furthermore, the double salt bridge ion selective electrode includes a silver / silver chloride reference electrode 1, a thermistor element 2, and a silver / silver chloride reference electrode wire 3. The bottom of the double salt bridge ion selective electrode is provided with a chloride ion selective polymer membrane 4. An internal filling solution 5 is provided above the ion selective polymer membrane 4, and a salt bridge 6 is provided above the internal filling solution 5. The bottoms of the silver / silver chloride reference electrode 1 and the thermistor element 2 are inserted into the salt bridge 6, and the bottom of the silver / silver chloride reference electrode wire 3 is inserted into the internal filling solution 5;

[0026] Furthermore, the silver / silver chloride reference electrode 1 includes a left glass tube and a silver / silver chloride reference electrode wire 3 located inside the left glass tube. An internal reference solution 7 is provided inside the left glass tube, and a porous ceramic core 8 is provided at the bottom of the left glass tube. The thermistor element includes a right glass tube 9 and a thermistor lead 10 located inside the right glass tube. A thermistor 11 is provided at the bottom of the thermistor lead 10, and a thermal conductive silicone grease 12 is provided at the bottom of the right glass tube 9;

[0027] Furthermore, the internal reference solution is a 3 mol / L potassium chloride solution; the internal filling solution is 10 -3 -10-1 A chloride ion solution with a concentration of -2 mol / L. The preferred concentration in this embodiment is 10

[0028] mol / L; A porous ceramic core 8 is provided on one side of the double salt bridge ion selective electrode; Example 2

[0029] The addition amounts of the chloride ion carrier 4,5-dimethyl-3,6-dioctyloxy-o-phenylene-bis(mercuric trifluoroacetate) are 0.2 mg, 0.5 mg, 1 mg, and 5 mg respectively, and the others are the same as in Example 1. The test results are shown in Table 1. Example 3

[0030] The ion localizer is 0.5 mg of tetraoctylammonium chloride, and the addition amounts of the chloride ion carrier 4,5-dimethyl-3,6-dioctyloxy-o-phenylene-bis(mercuric trifluoroacetate) are 0.2 mg, 0.5 mg, 1 mg, 2 mg, and 5 mg respectively, and the others are the same as in Example 1. The test results are shown in Table 1. Example 4

[0031] The plasticizer is 132 mg of o-nitrophenyl octyl ether or 132 mg of dibutyl phthalate, and the others are the same as in Example 1. The test results are shown in Table 2. Example 5

[0032] On the basis of Example 1, voltage detection is carried out every 1, 7, 14, 20, 30, and 60 days respectively. The test solution is a solution with a chloride ion concentration of 100 mg / L. During the test interval, the electrode is immersed in a chloride ion solution with a concentration of 10 mg / L. The test data are shown in Table 3. Example 6

[0033] The competing products 1 and 2 are tested according to Example 5, and the data are shown in Table 4.

[0034] Table 1 Influence of ion localizer on membrane Nernst response

[0035] Chloride ion carrier / mg Tetraoctylammonium chloride / mV Dodecylammonium chloride / mV 0.2 ＜3 ＜5 0.5 15 22 1 53.2 76.8 2 80.3 112.5 5 76.6 110.8

[0036] Table 2 Influence of plasticizer on membrane Nernst response

[0037] o-Nitrophenyl octyl ether Dioctyl sebacate Dibutyl phthalate Voltage / mV 52.3 115.1 87.3

[0038] Table 3 Stability of the membrane

[0039] Number of days 1 7 14 20 30 60 Voltage / mV 113.2 112.1 112.0 110.3 109.1 106.5

[0040] Table 4 Comparison data with market competing products

[0041] 1 day 30 days 60 days Competitor 1 70.1 mV 50.1 mV 46.2 mV Competitor 2 89.2 mV 88.7 mV 76.4 mV Self-produced 113.2 109.1 mV 106.5 mV

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application rather than to limit them. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application, and they should all be covered within the scope of the claims of the present application.

Claims

1. A preparation method of a chloride ion selective polymeric membrane electrode, characterized in that, The preparation steps are as follows: S1 Mix the chloride ion carrier, polymer, plasticizer, ion localizer and solvent evenly, and stir at a speed of 400 - 1000 rpm for 2 - 5 hours to obtain a clear and transparent solution; S2 Place the glass plate on a horizontal workbench, place it in a fume hood, and coat the solution obtained in step S1 on the glass plate with a wet film coater to obtain a wet film, and the coating thickness is 50 μm or 100 μm or 150 μm or 200 μm; S3 Let the wet film dry naturally at 20 - 25 °C for 2 - 5 hours, and then place the glass plate in a vacuum drying oven and dry it at 20 - 25 °C for 8 - 12 hours to obtain a polymer film; S4 Dissolve the chloride salt in water to prepare a salt solution with a chloride ion concentration of 100 μM - 100 mM, then immerse the polymer film in the salt solution for 12 - 36 hours, and then wash it clean with a large amount of ultrapure water to complete the preparation of the membrane; S5 Cut the membrane and assemble it into a double salt bridge ion selective electrode; The ion localizer is dodecylammonium chloride; The mass ratio of the chloride ion carrier, polymer, plasticizer and ion localizer is 1 - 8:100 - 150:200 - 300:0.1 - 2. The chloride ion carrier is 4,5 - dimethyl - 3,6 - dioctyloxy - o - phenylenediyl - bis(mercuric trifluoroacetate), the polymer is polyvinyl chloride, and the plasticizer is di - n - octyl sebacate; The double salt bridge ion selective electrode includes a silver / silver chloride reference electrode, a thermistor element and a silver / silver chloride reference electrode wire. The bottom of the double salt bridge ion selective electrode is provided with a chloride ion selective polymer membrane. An internal filling solution is provided above the chloride ion selective polymer membrane, and a salt bridge is provided above the internal filling solution. The bottoms of the silver / silver chloride reference electrode and the thermistor are inserted into the salt bridge, and the bottom of the silver / silver chloride reference electrode wire is inserted into the internal filling solution; The silver / silver chloride reference electrode includes a left glass tube and a silver / silver chloride reference electrode wire located inside the left glass tube. An internal reference solution is provided inside the left glass tube, and a porous ceramic core is provided at the bottom of the left glass tube. The thermistor element includes a right glass tube and a thermistor lead located inside the right glass tube. A thermistor is provided at the bottom of the thermistor lead, and thermal conductive silicone grease is provided at the bottom of the right glass tube; A porous ceramic core is provided on one side of the double salt bridge ion selective electrode.

2. The preparation method of a chloride ion selective polymeric membrane electrode according to claim 1, characterized in that, The internal reference solution is a 3 mol / L potassium chloride solution; the internal filling solution is a -3 -10 -1 mol / L chloride ion solution.

3. The preparation method of a chloride ion selective polymeric membrane electrode according to claim 1, characterized in that, The solvent in S1 is tetrahydrofuran or cyclohexanone; the chloride salt in S4 is one or more of sodium chloride, potassium chloride, magnesium chloride, ferric chloride, ferrous chloride.

4. The preparation method of a chloride ion selective polymeric membrane electrode according to claim 1, characterized in that, The volume ratio of the solvent to the total mass of the chloride ion carrier, polymer, plasticizer and ion localizer is 10 - 20 mL:1 - 3 g.

5. The preparation method of a chloride ion selective polymeric membrane electrode according to claim 1, characterized in that, The polyvinyl chloride can be replaced by polymethyl methacrylate; the di - n - octyl sebacate can be replaced by o - nitrophenyl octyl ether or / and dibutyl phthalate.

6. The preparation method of a chloride ion selective polymeric membrane electrode according to claim 1, characterized in that, The dodecylammonium chloride can be replaced by tetraoctylammonium chloride.

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