A device for rapid and accurate testing of isoelectric point

Abstract

A device for quickly and accurately testing isoelectric point, comprising a stirred tank, a sampling and measuring device and a pH adjusting device; a pH meter is arranged in the stirred tank; the sampling and measuring device comprises an automatic sampler, an automatic sample injector and a plurality of vacuum sample tubes, the plurality of vacuum sample tubes are arranged on a rotating frame and rotate with the rotating frame, a feeding pipe of the automatic sampler is communicated with the stirred tank, a discharging pipe of the automatic sampler is communicated with the automatic sample injector, the automatic sample injector is located above the rotating frame and inserts into the plurality of vacuum sample tubes in sequence to inject sample as the rotating frame rotates; the pH adjusting device comprises a plurality of liquid storage tanks, each liquid storage tank is communicated with the stirred tank through a pipeline I, and different concentrations of acid solution or alkali solution are stored in each liquid storage tank. The device can quickly and accurately test isoelectric point and is very suitable for industrial production detection.

Description

Technical Field

[0001] This utility model belongs to the field of new energy batteries, and specifically relates to a device for rapidly and accurately testing the isoelectric point. Background Technology

[0002] During the synthesis of Prussian blue cathode materials via co-precipitation, unbonded sites exist on the particle surface. Complex ions in the solution can bond to these sites, charging the particle surface and forming an adsorption layer. Particles with the same charge repel each other, making it difficult for them to aggregate. Even during the homogenization process, the presence of this adsorption layer can affect the stability of the slurry, thus requiring monitoring of the surface charge state.

[0003] Hydrogen ions or hydroxide ions can neutralize surface charges. When the surface charge of the particles is zero, the pH value of the solution is the isoelectric point (IEP) of the colloid. Therefore, the isoelectric point can be used as a physicochemical indicator of the amount of charge carried on the particle surface. Furthermore, whether the material is thoroughly cleaned is a key concern for Prussian blue during the actual cleaning process. In cases of incomplete cleaning, electrolytes adsorbed on the particle surface cause a shift in the IEP value. This shift in the IEP value can be used to determine whether the material is properly cleaned.

[0004] Instruments for testing IEP include zeta potentiometers, laser particle size analyzers, and multiple light scattering stability analyzers. However, these devices are expensive, and zeta potentiometers require the preparation of calibration solutions with different pH values, which is a relatively complex process. Furthermore, excessively high electrolyte concentrations do not meet the testing requirements, making it difficult to handle large numbers of samples in actual production.

[0005] To monitor the isoelectric point of a sample, a low-cost and easy-to-operate testing instrument is needed. Summary of the Invention

[0006] To address the problems existing in the background art, this utility model provides a device for rapidly and accurately testing equipotential points.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A device for rapidly and accurately testing the isoelectric point includes a stirred tank, a sampling and measuring device, and a pH adjusting device. A pH meter is installed inside the stirred tank. The sampling and measuring device includes an automatic sampler, an automatic injector, and several vacuum sample tubes. The vacuum sample tubes are placed on a rotating frame and rotate with the frame. The feed pipe of the automatic sampler is connected to the stirred tank, and the discharge pipe of the automatic sampler is connected to the automatic injector. The automatic injector is located above the rotating frame, and as the frame rotates, it sequentially inserts into several vacuum sample tubes to inject samples. The pH adjusting device includes several storage tanks, each connected to the stirred tank via a pipe I. Each storage tank contains acid or alkali solutions of different concentrations.

[0009] Furthermore, a peristaltic pump is installed on pipe I.

[0010] Furthermore, a control valve is installed at the outlet of each storage tank.

[0011] Furthermore, the device for rapidly and accurately testing equipotential points also includes a cleaning device, which is connected to pipe I and the feed pipe of the sampler via cleaning pipes.

[0012] Furthermore, a cleaning valve is installed on the cleaning pipe.

[0013] Furthermore, an air vent valve is provided at the bottom of the mixing vessel.

[0014] Furthermore, a stirring device is provided inside the stirring vessel.

[0015] Furthermore, the side wall of the stirred tank is provided with a cavity, which is connected to an external water source.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] In the prior art, the isoelectric point can be determined by visually observing the precipitation. However, visual precipitation can lead to the addition of excessive acid or alkali due to pH transitions, so the accuracy of determining the isoelectric point by visual precipitation is not high.

[0018] This invention alleviates pH transitions by adding acid or alkali solutions of different concentrations, and continuously samples to observe the aggregation. The more samples taken, the higher the accuracy. The pH value of the sample that just aggregates is the isoelectric point.

[0019] This invention provides a device for rapidly and accurately testing the isoelectric point to evaluate the quality of each batch of synthesized products. This device serves as a physicochemical indicator of the product, reflecting the ion adsorption on the surface of the product particles. The testing device has a simple structure, low cost, and can rapidly and accurately test the isoelectric point, making it highly suitable for industrial production testing. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall device structure of this utility model;

[0021] Figure 2 This is a schematic diagram of the automatic sampler and rotating frame structure of this utility model;

[0022] In the diagram, 1 is the mixing vessel, 2 is the sampling and testing device, 3 is the pH adjustment device, 4 is the feed pipe, 5 is the storage tank, 6 is pipe I, 7 is the peristaltic pump, 8 is the control valve, 9 is the cleaning device, 10 is the cleaning pipe, 11 is the cleaning valve, and 12 is the drain valve. Detailed Implementation

[0023] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model. Specific Implementation Method 1

[0025] A device for rapidly and accurately testing isoelectric points, such as Figure 1 As shown, the device includes a stirred tank 1, a sampling and measuring device 2, and a pH adjusting device 3. A pH meter is installed inside the stirred tank 1 to monitor pH changes in the material. The sampling and measuring device 2 includes an automatic sampler, an automatic injector, and several vacuum sample tubes. The vacuum sample tubes are placed on a rotating frame and rotate with the frame. The feed pipe 4 of the automatic sampler is connected to the stirred tank 1, continuously extracting samples from the stirred tank 1. The discharge pipe of the automatic sampler is connected to the automatic injector, which is located above the rotating frame. As the frame rotates, the automatic injector sequentially inserts into several vacuum sample tubes to inject samples. Both the automatic sampler and the automatic injector are existing technologies. A schematic diagram of the automatic injector is shown below. Figure 2 As shown. The pH adjustment device includes several storage tanks 5, each connected to a stirred tank 1 via a pipe I6. Each storage tank 5 contains acid or alkali solutions of different concentrations. The pH of the dispersion system in the stirred tank 1 is adjusted by adding acid or alkali solutions of different concentrations dropwise. Simultaneously, an automatic sampler continuously takes samples until pH adjustment is complete. A sample tube that has just begun to aggregate is selected from the vacuum sample tubes, and the pH of the dispersion in that sample tube is tested; this is the isoelectric point.

[0026] Furthermore, a peristaltic pump 7 is installed on the pipeline I6 to control the flow rate of the acid solution or alkaline solution, and different concentrations of acid or alkaline solution are added during the dripping process according to the pH change.

[0027] Furthermore, each storage tank 5 is equipped with a control valve 8 at its outlet to control the outflow of acid or alkali solutions.

[0028] Furthermore, the device for rapidly and accurately testing isoelectric points also includes a cleaning device 9, which is connected to pipe I6 and the sampler's feed pipe 4 via a cleaning pipe 10. A cleaning valve 11 is installed on the cleaning pipe 10. When the cleaning valve 11 is opened, the cleaning solution from the cleaning device 9 flows into pipe I6 and the sampler's feed pipe 4 for cleaning. The liquid is then discharged into the mixing vessel 1. An vent valve 12 is installed at the bottom of the mixing vessel 1. Opening the vent valve 12 discharges the waste liquid.

[0029] Furthermore, the mixing vessel 1 is equipped with a stirring device for stirring and dispersing materials to form a dispersion system. The stirring device has an existing structure, and the mixing vessel 1 is a semi-sealed device, through which a protective gas is introduced to isolate the air and protect the materials from oxidation.

[0030] Furthermore, the side wall of the stirring vessel 1 is provided with a clamping cavity, which is connected to an external water source and is used to control the temperature inside the stirring vessel 1.

[0031] Example 1:

[0032] 1. Close the drain valve 12, cleaning valve 11, and control valve 8. The storage tank 5 contains sulfuric acid with pH values ​​of 0.3, 1, and 2, respectively.

[0033] 2. Add 500mL of deoxygenated water to the mixing vessel 1, then add 60g of cleaned Prussian blue wet material and stir to disperse. Nitrogen gas is introduced for protection throughout the process.

[0034] 3. Open the control valve 8 of the storage tank 5 containing sulfuric acid with pH=2, set the flow rate of the peristaltic pump 7 to 3mL / min, and start the automatic sampler to take samples at the same time as the peristaltic pump 7 is turned on.

[0035] 4. Based on the pH changes in the stirred tank 1, open the sulfuric acid storage tanks 5 of different concentrations respectively to make the pH change stable.

[0036] 5. After obvious flocculation and stratification appear in the vacuum sample tube, stop feeding and sampling. Find the vacuum sample tube where flocculation just occurred and test the pH of the dispersion in that vacuum sample tube. The pH is 6.54, which is the isoelectric point.

[0037] 6. Open the drain valve 12 to drain the mixing tank 1, and open the cleaning valve 11 to flush the pipeline. The washing water is discharged from the drain valve 12.

[0038] Example 2:

[0039] 1. Close the drain valve 12, cleaning valve 11, and control valve 8. The storage tank 5 contains sulfuric acid with pH values ​​of 0.3, 1, and 2, respectively.

[0040] 2. Add 500mL of deoxygenated water to the stirred tank 1, then add 60g of unwashed Prussian blue wet material and stir to disperse. Nitrogen gas is introduced for protection throughout the process.

[0041] 3. Open the control valve 8 of the storage tank 5 containing sulfuric acid with pH=2, set the flow rate of the peristaltic pump 7 to 3mL / min, and start the automatic sampler to take samples at the same time as the peristaltic pump 7 is turned on.

[0042] 4. Based on the pH changes in the stirred tank 1, open the sulfuric acid storage tanks 5 of different concentrations respectively to make the pH change stable.

[0043] 5. After obvious flocculation and stratification appear in the vacuum sample tube, stop feeding and sampling. Find the sample tube where flocculation just occurred and test the pH of the dispersion in that sample tube to be 4.71, which is the isoelectric point.

[0044] 6. Open the drain valve 12 to drain the mixing tank 1, and open the cleaning valve 11 to flush the pipeline. The washing water is discharged from the drain valve 12.

[0045] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for rapidly and accurately testing isoelectric points, characterized in that: The device includes a stirred tank (1), a sampling and measuring device (2), and a pH adjusting device (3). The stirred tank (1) is equipped with a pH meter. The sampling and measuring device (2) includes an automatic sampler, an automatic injector, and several vacuum sample tubes. The several vacuum sample tubes are placed on a rotating frame and rotate with the rotating frame. The feed pipe (4) of the automatic sampler is connected to the stirred tank (1), and the discharge pipe of the automatic sampler is connected to the automatic injector. The automatic injector is located above the rotating frame. As the rotating frame rotates, the automatic injector sequentially inserts into several vacuum sample tubes to inject samples. The pH adjusting device (3) includes several storage tanks (5). Each storage tank (5) is connected to the stirred tank (1) through pipe I (6). Each storage tank (5) contains acid solutions or alkali solutions of different concentrations.

2. The device for rapidly and accurately testing equipotential points according to claim 1, characterized in that: A peristaltic pump (7) is installed on the pipeline I (6).

3. The device for rapidly and accurately testing equipotential points according to claim 1, characterized in that: Each storage tank (5) is equipped with a control valve (8) at its outlet.

4. The device for rapidly and accurately testing equipotential points according to claim 1, characterized in that: The device for rapid and accurate testing of isoelectric points also includes a cleaning device (9), which is connected to pipe I (6) and the feed pipe (4) of the sampler via a cleaning pipe (10).

5. The apparatus for rapidly and accurately testing equipotential points according to claim 4, characterized in that: A cleaning valve (11) is installed on the cleaning pipe (10).

6. The apparatus for rapidly and accurately testing equipotential points according to claim 1, characterized in that: The bottom of the stirring vessel (1) is equipped with an air vent valve (12).

7. The apparatus for rapidly and accurately testing equipotential points according to claim 1, characterized in that: The stirring vessel (1) is equipped with a stirring device.

8. The apparatus for rapidly and accurately testing equipotential points according to claim 1, characterized in that: The side wall of the stirred tank (1) is provided with a cavity, which is connected to an external water source.

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