Airless methane sulfonic acid leacheate generator for liquid phase ion chromatography

Abstract

The invention discloses an airless methane sulfonic acid leacheate generator for liquid phase ion chromatography, which comprises a shell, a first heterogeneous anion exchange membrane, a first homogeneous anion exchange membrane, a second heterogeneous anion exchange membrane, anion exchange resin, a bipolar membrane, a third heterogeneous anion exchange membrane, a second homogeneous anion exchange membrane and a fourth heterogeneous anion exchange membrane are sequentially arranged in the shell, a cathode chamber is formed between one side, far away from the first homogeneous anion exchange membrane, of the first heterogeneous anion exchange membrane and the inner wall of the shell, an anode chamber is formed between one side, far away from the second homogeneous anion exchange membrane, of the fourth heterogeneous anion exchange membrane and the inner wall of the shell, and a cathode plate is arranged in the cathode chamber; an anode plate is arranged in the anode chamber, the anode plate and the cathode plate are connected with a power supply, the generator can generate the airless methane sulfonic acid leacheate for liquid phase ion chromatography, and the generator is simple in structure and small in size.

Description

Technical Field

[0001] This invention relates to a generator, specifically to a generator for gasless methanesulfonic acid eluent for liquid ion chromatography. Background Technology

[0002] The liquid ion chromatography (LICC) generator is a core component of an ion chromatography system, and its technological development has undergone a revolutionary transformation from manual eluent preparation to online automated generation. The eluent generator is used to electrolyze and produce high-purity eluent for isocratic or gradient elution. For measuring the cation content in water samples, liquid chromatography requires a methanesulfonic acid eluent generator, and its performance directly affects the various chromatographic detection performances. The methanesulfonic acid eluent generator can prevent baseline drift during chromatographic measurements, increase detection sensitivity, improve component resolution, and ensure good reproducibility of chromatographic peak integration.

[0003] Publication No. CN101377477A discloses an automatic eluent generator for ion chromatography, comprising a generating chamber, a cathode chamber, and an anode chamber. The generating chamber is located between a cation exchange membrane and an anion exchange membrane. The other end of the cation exchange membrane is the anode chamber, with the anode inside. The other end of the anion exchange membrane is the cathode chamber, with the cathode inside. Electrochemical corrosion resistant coupling devices are installed in the anode and cathode chambers to allow the eluent concentrate, gas, and current to pass through. The generating chamber is filled with cation and anion exchange resin fibers. The side of the generating chamber closest to the cation exchange membrane is filled with anion exchange resin fibers, and the side closest to the anion exchange membrane is filled with cation exchange resin fibers. The coupling device is a porous titanium plate wound with platinum wire, preferably with pores of 5-8 μm in diameter. The electrolytic capacitor is a single unit that can be directly placed in the cathode or anode chamber, making it easy to install. It serves a dual function as a liquid flow channel and an electrolytic electrode. As a liquid flow channel, it has good pressure resistance and is not easily blocked. As an electrolytic electrode, it has low resistance, high electrolysis efficiency, and corrosion resistance, requiring less suppression current compared to ion exchange resins. Due to its dual-membrane structure, only ion exchange occurs between the generating chamber and the anode and cathode chambers. Oxygen generated in the anode chamber and hydrogen generated in the cathode chamber do not enter the generating chamber. Therefore, this invention eliminates the need for a degassing device, automatically preparing the eluent online for ion chromatography. This eliminates the need for manual eluent preparation during ion chromatography operation. It can run continuously for weeks or even longer with just water. This device simplifies and simplifies ion chromatography operation, resulting in more accurate and reliable data. It ensures high reproducibility and comparability of experimental data from different personnel, locations, and times.

[0004] Defects and shortcomings of existing technology: Currently, most methanesulfonic acid eluent generators use a single-membrane method, meaning they only use an anion exchange membrane to separate the anode chamber, cathode chamber, and packing chamber. The biggest drawback of this single-membrane method is: 1. During the reaction process, the gases (hydrogen and oxygen) generated at the cathode and anode can easily pass through the anion exchange membrane into the packing chamber. The gases are carried into the chromatographic detection system through the packing chamber, which will increase the noise of the chromatographic detection baseline. Excessive bubbles will also accumulate in the resin column, reducing the component separation effect.

[0005] 2. In order to eliminate the problem of easy gas permeation in single-membrane methods, degassing devices have been introduced into chromatography. These devices are generally complex in structure and large in size, which increases the maintenance workload of the chromatography measurement system. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a gasless methanesulfonic acid eluent generator for liquid ion chromatography. This generator can generate gasless methanesulfonic acid eluent for liquid ion chromatography and has a simple structure and small size.

[0007] To achieve the above objectives, this invention discloses a gasless methanesulfonic acid eluent generator for liquid ion chromatography, comprising a housing. Inside the housing are sequentially arranged a first heterogeneous anion exchange membrane, a first homogeneous anion exchange membrane, a second heterogeneous anion exchange membrane, an anion exchange resin, a bipolar membrane, a third heterogeneous anion exchange membrane, a second homogeneous anion exchange membrane, and a fourth heterogeneous anion exchange membrane. A cathode chamber is formed between the side of the first heterogeneous anion exchange membrane away from the first homogeneous anion exchange membrane and the inner wall of the housing. An anode chamber is formed between the side of the fourth heterogeneous anion exchange membrane away from the second homogeneous anion exchange membrane and the inner wall of the housing. A cathode plate is disposed within the cathode chamber, and an anode plate is disposed within the anode chamber. Both the anode plate and the cathode plate are connected to a power source.

[0008] A further improvement of the gasless methanesulfonic acid eluent generator for liquid ion chromatography described in this invention is as follows: Furthermore, a methanesulfonic acid solution is introduced into both the cathode chamber and the anode chamber.

[0009] Furthermore, the area where the anion exchange resin is located is a packing chamber.

[0010] Furthermore, high-purity water is introduced into the packing chamber.

[0011] Furthermore, the following reactions occur in the anode chamber and the cathode chamber, respectively: Cathode chamber:

[0012] Anode chamber:

[0013] Furthermore, during initial use, the anion exchange resin in the form of methanesulfonic acid is soaked in a methanesulfonic acid solution.

[0014] Furthermore, the power supply is a constant current power supply.

[0015] Furthermore, the gases generated in the anode and cathode chambers cannot permeate the membrane into the intermediate packing chamber.

[0016] Furthermore, the cathode plate and anode plate are made of platinum sheets.

[0017] Furthermore, the first heterogeneous anion exchange membrane, the first homogeneous anion exchange membrane, the second heterogeneous anion exchange membrane, the bipolar membrane, the third heterogeneous anion exchange membrane, the second homogeneous anion exchange membrane, and the fourth heterogeneous anion exchange membrane are distributed in parallel.

[0018] The present invention has the following beneficial effects: The gasless methanesulfonic acid eluent generator for liquid ion chromatography described in this invention, through a redesigned structural layout incorporating bipolar membranes, homogeneous anion exchange membranes, and heterogeneous anion exchange membranes based on the traditional single-membrane eluent generator design, can continuously prepare gasless methanesulfonic acid eluent for ion chromatography under the influence of an electric field. It should be noted that the bipolar membrane used in this invention can directly hydrolyze and generate H₂. + The design of the packing chamber improves the efficiency of preparing methanesulfonic acid eluent. This invention employs a combination of homogeneous and heterogeneous anion exchange membranes, balancing ion migration efficiency and membrane mechanical strength, making it suitable for high-pressure chromatography systems. This invention can prepare gas-free methanesulfonic acid eluent, avoiding the introduction of a degassing system into the ion chromatography system, simplifying the chromatographic analysis process, and reducing chromatographic maintenance costs. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a structural diagram of the present invention.

[0020] Among them, 1 is the cathode chamber, 2 is the cathode plate, 3 is the first heterogeneous anion exchange membrane, 4 is the first homogeneous anion exchange membrane, 5 is the second heterogeneous anion exchange membrane, 6 is the anion exchange resin, 7 is the bipolar membrane, 8 is the third heterogeneous anion exchange membrane, 9 is the second homogeneous anion exchange membrane, 10 is the fourth heterogeneous anion exchange membrane, 11 is the anode plate, 12 is the anode chamber, and 13 is the power supply. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0025] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0026] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0029] Example 1 The gasless methanesulfonic acid eluent generator for liquid ion chromatography of the present invention includes a housing. Inside the housing, a first heterogeneous anion exchange membrane 3, a first homogeneous anion exchange membrane 4, a second heterogeneous anion exchange membrane 5, an anion exchange resin 6, a bipolar membrane 7, a third heterogeneous anion exchange membrane 8, a second homogeneous anion exchange membrane 9, and a fourth heterogeneous anion exchange membrane 10 are sequentially arranged. A cathode chamber 1 is formed between the side of the first heterogeneous anion exchange membrane 3 away from the first homogeneous anion exchange membrane 4 and the inner wall of the housing. An anode chamber 12 is formed between the side of the fourth heterogeneous anion exchange membrane 10 away from the second homogeneous anion exchange membrane 9 and the inner wall of the housing. A cathode plate 2 is disposed in the cathode chamber 1, and an anode plate 11 is disposed in the anode chamber 12. The anode plate 11 and the cathode plate 2 are connected to a power supply 13. The first heterogeneous anion exchange membrane 3, the first homogeneous anion exchange membrane 4, the second heterogeneous anion exchange membrane 5, the bipolar membrane 7, the third heterogeneous anion exchange membrane 8, the second homogeneous anion exchange membrane 9, and the fourth heterogeneous anion exchange membrane 10 are distributed in parallel.

[0030] It should be noted that this invention, by introducing a bipolar membrane 7, a homogeneous anion exchange membrane, and a heterogeneous anion exchange membrane into the traditional single-membrane eluent generator design, redesigns the structural layout. Under the action of an electric field, it can continuously prepare gas-free methanesulfonic acid eluent for ion chromatography. The generator is designed with three chambers (anode chamber 12, cathode chamber 1, and packing chamber). The following reactions occur in anode chamber 12 and cathode chamber 1, respectively: Cathode chamber 1:

[0031] Anode chamber 12:

[0032] A 4 mol / L methanesulfonic acid solution is introduced into the anode chamber 12 and the cathode chamber 1. Its main function is to provide sufficient methanesulfonic acid ions. Under the action of the electric field, the methanesulfonic acid ions can pass through the anion exchange membrane into the packed chamber.

[0033] Example 2 refer to Figure 1 To further improve this application, the gasless methanesulfonic acid eluent generator for liquid ion chromatography of the present invention includes a housing, within which are sequentially arranged a first heterogeneous anion exchange membrane 3, a first homogeneous anion exchange membrane 4, a second heterogeneous anion exchange membrane 5, an anion exchange resin 6, a bipolar membrane 7, a third heterogeneous anion exchange membrane 8, a second homogeneous anion exchange membrane 9, and a fourth heterogeneous anion exchange membrane 10, wherein the first heterogeneous anion exchange membrane 3 is located away from the first homogeneous anion exchange membrane 4. A cathode chamber 1 is formed between one side of the fourth heterogeneous anion exchange membrane 10 and the inner wall of the shell. An anode chamber 12 is formed between the side of the fourth heterogeneous anion exchange membrane 10 away from the second homogeneous anion exchange membrane 9 and the inner wall of the shell. A cathode plate 2 is disposed in the cathode chamber 1, and an anode plate 11 is disposed in the anode chamber 12. The anode plate 11 and the cathode plate 2 are connected to a power supply 13. An acid solution is introduced into both the cathode chamber 1 and the anode chamber 12. The area where the anion exchange resin 6 is located is a packing chamber, and high-purity water is introduced into the packing chamber.

[0034] Platinum plates are placed in the anode chamber 12 and the cathode chamber 1 as cathode plate 2 and anode plate 11, respectively. Wires are led out from the cathode plate 2 and anode plate 11, and a constant current is provided by a 24V constant current power supply 13. The power supply 13 can automatically adjust the voltage value to keep the reaction current required by the system constant.

[0035] The packing chamber is filled with anion exchange resin 6. When the resin is initially used, it is soaked in methanesulfonic acid solution to become methanesulfonic acid type anion exchange resin 6, which facilitates the initial use of the generator and can also provide sufficient methanesulfonic acid ions from the resin.

[0036] The cathode chamber 1 and the packing chamber are arranged in the following order: cathode plate 2 - heterogeneous anion exchange membrane - homogeneous anion exchange membrane - heterogeneous anion exchange membrane; the packing chamber and the anode chamber 12 are arranged in the following order: bipolar membrane 7 - heterogeneous anion exchange membrane - homogeneous anion exchange membrane - heterogeneous anion exchange membrane - anode plate 11.

[0037] The different types of membranes mentioned above are explained as follows: Anion exchange membranes are functional polymer materials that selectively allow anions to pass through while blocking cations and molecules. They are widely used in electrochemical energy conversion, water treatment, and chemical separation. They only allow anions (such as...) (methanesulfonate ions) permeate; Homogeneous anion exchange membranes: Ion exchange groups (such as quaternary ammonium groups, pyridinium groups, etc.) are uniformly introduced into a polymer matrix (such as polystyrene, polyethersulfone, polyolefins, etc.) through chemical grafting or radiation polymerization, forming a homogeneous structure without phase interfaces. Its core principle is: Ion exchange mechanism: The fixed groups within the membrane carry a positive charge, attracting anions through electrostatic interaction while repelling cations, achieving selective anion permeation. Optimized conduction path: The homogeneous structure eliminates the interfacial defects between resin particles and binders in heterogeneous membranes, forming continuous ion conduction channels, reducing membrane resistance, and improving ion migration efficiency. While the uniform distribution of exchange groups results in low resistance and high exchange efficiency, it also leads to poor mechanical strength and is not suitable for high-voltage systems. Heterogeneous anion exchange membranes: These are ion exchange membranes made by physically mixing anion exchange resin powder with a binder. Their chemical structure is non-uniform, with resin particles dispersed within the binder matrix, exhibiting a distinct phase interface. The ion exchange resin is embedded in an inert matrix, resulting in high mechanical strength but also high electrical resistance. This makes them suitable for high-voltage systems, although their exchange efficiency is generally low. Bipolar membrane 7: Composed of a cation exchange layer (N-type membrane), an intermediate catalyst layer, and an anion exchange layer (P-type membrane). Its core function is to dissociate water into hydrogen ions under the action of a DC electric field. ) and hydroxide ions ( The water molecules migrate to the main solution through the cation and anion exchange membranes respectively. The anion / cation exchange layer composite can achieve water molecule dissociation under the action of an electric field. This type of membrane must be assembled in a specific orientation when used. In this patent, H is hydrolyzed as shown in the figure. + One side faces the packing chamber, so that the H generated by the bipolar membrane 7 + The methanesulfonic acid ions that migrate from cathode chamber 1 to the packing chamber combine to form a methanesulfonic acid solution.

[0038] The packing chamber is filled with ultrapure water with a resistivity of 18.2 MΩ / cm. Both the cathode chamber 1 and the anode chamber 12 are circulated with a 4 mmol / L methanesulfonic acid solution. Under these conditions, the required specific concentration (0-20 mmol / L) of methanesulfonic acid rinsing solution can be produced on a large scale.

[0039] Due to the use of a multi-layer composite membrane design, the gas generated in the anode chamber 12 and the cathode chamber 1 cannot pass through the membrane into the intermediate packing chamber. The entire system produces gas-free methanesulfonic acid eluent, avoiding the need to add a more complex degassing system to the chromatography.

[0040] This invention introduces high-purity water into the packed chamber and sets a constant current source (0-80mA). Under the influence of the electric field, anions migrate towards the anode, and cations migrate towards the cathode. A 4 mmol / L methanesulfonic acid solution (acid solution) is introduced into the anode chamber 12 and the cathode chamber 1. The anode chamber 12 and the cathode chamber 1 can be connected in series. The used methanesulfonic acid solution can be recycled. The purpose of using methanesulfonic acid is to continuously supply methanesulfonic acid ions to the cathode chamber 1. Under the influence of the electric field, the methanesulfonic acid ions continuously pass through the anion exchange membrane into the packed chamber. The cathode chamber 1 also requires water to maintain the electrolysis reaction. To simplify the system, both chambers use methanesulfonic acid solution. The bipolar membrane 7 continuously electrolyzes under the influence of the electric field to produce H₂. + Under the influence of the electric field, the gas migrates towards the anode and enters the packing chamber to combine with methanesulfonic acid ions to form the desired methanesulfonic acid eluent. Due to the multilayer membrane composite design, the gas generated in the cathode chamber 1 and the anode chamber 12 cannot enter the intermediate packing chamber. As the acid solution circulating in the anode chamber 12 and the cathode chamber 1 is discharged from the system, the desired gas-free methanesulfonic acid eluent is finally obtained.

[0041] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0042] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0043] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An air-free methanesulfonic acid eluent generator for liquid phase ion chromatography, characterized by The application relates to a device for producing hydrogen and oxygen by electrolysis of water, which comprises a shell, wherein a first heterogeneous anion exchange membrane (3), a first homogeneous anion exchange membrane (4), a second heterogeneous anion exchange membrane (5), an anion exchange resin (6), a bipolar membrane (7), a third heterogeneous anion exchange membrane (8), a second homogeneous anion exchange membrane (9) and a fourth heterogeneous anion exchange membrane (10) are sequentially arranged in the shell, wherein a cathode chamber (1) is formed between the inner wall of the shell and the side of the first heterogeneous anion exchange membrane (3) far from the first homogeneous anion exchange membrane (4), an anode chamber (12) is formed between the inner wall of the shell and the side of the fourth heterogeneous anion exchange membrane (10) far from the second homogeneous anion exchange membrane (9), a cathode plate (2) is arranged in the cathode chamber (1), an anode plate (11) is arranged in the anode chamber (12), and the anode plate (11) and the cathode plate (2) are connected with a power supply (13).

2. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 1, characterized in that, Methane sulfonic acid solution is introduced into the cathode chamber (1) and the anode chamber (12).

3. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 1, characterized in that, The area where the anion exchange resin (6) is located is a filler chamber.

4. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 3, characterized in that, High-purity water is introduced into the filler chamber.

5. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 1, characterized in that, The following reactions occur in the anode chamber (12) and the cathode chamber (1) respectively: Cathode compartment (1): Anode compartment (12): .

6. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 1, characterized in that, When initially used, the anion exchange resin (6) in the methane sulfonic acid type is soaked in methane sulfonic acid solution.

7. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 1, characterized in that, The power supply (13) is a constant current power supply.

8. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 3, characterized in that, The gas produced by the anode chamber (12) and the cathode chamber (1) cannot pass through the membrane into the middle filler chamber.

9. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 1, characterized in that, The material of the cathode plate (2) and the anode plate (11) is platinum.

10. The gas-free methane sulfonic acid eluent generator for liquid ion chromatography according to claim 1, wherein, The first heterogeneous anion exchange membrane (3), the first homogeneous anion exchange membrane (4), the second heterogeneous anion exchange membrane (5), the bipolar membrane (7), the third heterogeneous anion exchange membrane (8), the second homogeneous anion exchange membrane (9) and the fourth heterogeneous anion exchange membrane (10) are parallelly distributed.

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