Purification system

Abstract

A purification system is provided. The purification system comprises a material adding device, an extraction device, a concentration device, a waste liquid collecting device, a valve structure and a first spectrum detector. The material adding device can be controlled to add various materials into the extraction device. The concentration device and the waste liquid collecting device are connected to an outlet of the extraction device through a valve structure, and the valve structure is configured to be capable of switching between communication between the extraction device and the concentration device, communication between the extraction device and the waste liquid collecting device and non-communication between the extraction device and the waste liquid collecting device. The first spectrum detector is configured to be capable of detecting the spectrum information of the material flowing out of the outlet of the extraction device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quantum dot production, and in particular to a purification system. BACKGROUND

[0002] In a quantum dot stock solution, in addition to quantum dots, there are unreacted precursors, by-products, solvents, etc. The traditional purification method is to place the suspension of the stock solution mixed with a poor solvent in a centrifuge tube, centrifuge and settle it with a common commercial centrifuge, and then redissolve it with a good solvent. The volume of the quantum dot stock solution, the poor solvent, and the good solvent, the speed of the centrifuge, and the length of time for centrifugation all need to be accurate, otherwise the consistency of the quantum dots after purification may be a problem. Moreover, the whole process is repetitive and tedious, and personnel are exposed to an organic solvent environment. Based on the consideration of the consistency of quantum dots, it is particularly important to develop a purification process that meets the purification requirements and is suitable for automation. CONTENT OF THE INVENTION

[0003] To solve or alleviate at least one of the problems mentioned in the background art, the present application provides a purification system.

[0004] The purification system provided by the embodiments of the present application comprises:

[0005] a material adding device;

[0006] an extraction device, the material adding device being capable of adding a plurality of materials to the extraction device in a controlled manner;

[0007] a concentration device, a waste liquid collecting device, and a valve structure, the concentration device and the waste liquid collecting device being connected to the outlet of the extraction device through the valve structure, the valve structure being configured to be capable of switching between the extraction device being communicated with the concentration device, being communicated with the waste liquid collecting device, and neither being communicated.

[0008] a first spectrum detector, the first spectrum detector being configured to be capable of detecting the spectral information of the material flowing out of the outlet of the extraction device.

[0009] In at least one embodiment, a stirrer is provided in the extraction device.

[0010] In at least one embodiment, the purification system comprises a vacuum pump for pumping gaseous solvent in the concentration device.

[0011] In at least one embodiment, the concentration device has a liquid level identification device for identifying the liquid level of the remaining material in the concentration device.

[0012] In at least one embodiment, the liquid level identification device is a second spectrometer or a photometer configured to detect absorbance at a predetermined liquid level to determine the height relationship between the liquid level of the remaining material and the predetermined liquid level; and / or the liquid level identification device is a liquid level sensor.

[0013] In at least one embodiment, the concentration device is at least partially transparent, and a scale line is provided on the concentration device.

[0014] In at least one embodiment, the concentration device is provided with an observation window through which the liquid level can be observed.

[0015] In at least one embodiment, the purification system further comprises a collection bottle connected to the outlet of the concentration device.

[0016] In at least one embodiment, the purification system comprises a gas adding device comprising an extraction device applying end for applying gas to the extraction device so that the liquid in the extraction device can be discharged under pressure.

[0017] In at least one embodiment, the purification system comprises a gas adding device comprising a concentration device applying end for applying gas to the concentration device so that the liquid in the concentration device can be discharged under pressure.

[0018] The present application can realize automatic purification of quantum dots by providing an extraction device, a valve structure and a material adding device. The first spectrometer can monitor the composition of the liquid flowing through, which helps the system to collect the quantum dot solution after extraction automatically, and helps to realize automatic purification of quantum dots. The workers do not have to expose to the organic solvent environment, which is safer. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A schematic diagram of a purification system according to an embodiment of the present application is shown.

[0020] REFERENCE SIGNS

[0021] 100 material adding device

[0022] 110 pump

[0023] 200 extraction device

[0024] 210 stirrer

[0025] 300 concentration device

[0026] 400 waste liquid collection device

[0027] 500 valve structure

[0028] 610 first light spectrum detector

[0029] 620 second light spectrum detector

[0030] 700 collection bottle

[0031] 800 gas adding device

[0032] 801 gas source

[0033] 802 pressure reducing valve

[0034] 803 first mass flow controller

[0035] 804 second mass flow controller

[0036] 810 extraction device applying end

[0037] 820 concentration device applying end DETAILED DESCRIPTION

[0038] The exemplary embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood that the specific description is only for teaching those skilled in the art how to implement the present application, and is not intended to exhaust all possible ways of the present application, nor to limit the scope of the present application.

[0039] The inventors found that in a two-liquid-phase system composed of a polar solvent and a non-polar solvent, the distribution coefficients of oily ligand quantum dots and impurities (unreacted precursors, by-products, etc.) in the two liquid phases are different, the quantum dots are easily dispersed in the non-polar solvent, and the impurities are easily dispersed in the polar solvent.

[0040] In view of this feature, the present application provides a purification system having a two-liquid-phase extraction system composed of a polar solvent and a non-polar solvent, which can realize liquid-phase extraction and concentration of quantum dots, for example, and realize purification of quantum dots. Of course, the purification system provided by the present application can also be used for purification of other substances.

[0041] More specifically, referring to Figure 1 , the purification system can include a material adding device 100, an extraction device 200, a concentration device 300, a waste liquid collecting device 400, a valve structure 500, and a first light spectrum detector 610.

[0042] The material adding device 100 can add multiple materials to the extraction device 200 in a controlled manner. For example, a polar solvent, a non-polar solvent, and a quantum dot stock solution can be added to the extraction device 200. After mixing and standing in the extraction device 200, the materials will be separated into two liquid phases. The upper liquid phase dissolves quantum dots, and the lower liquid phase dissolves impurities.

[0043] The concentration device 300 and the waste liquid collection device 400 are connected to the outlet of the extraction device 200 through a valve structure 500. The valve structure 500 is configured to be able to switch between the extraction device 200 being communicated to the concentration device 300, being communicated to the waste liquid collection device 400, and neither. Illustratively, the valve structure 500 can be a three-way electromagnetic valve, which comprehensively opens and closes the passage. Alternatively, the valve structure includes two electromagnetic valves, which respectively control whether the channels to the concentration device 300 and the waste liquid collection device 400 are communicated.

[0044] The first spectrum detector 610 is configured to detect the spectral information of the material flowing out of the outlet of the extraction device 200. The first spectrum detector 610 can be an ultraviolet spectrum monitor. Through the spectral information, the type of the material can be analyzed, which can include waste and quantum dots.

[0045] The valve structure 500 can be first controlled to realize the communication between the extraction device 200 and the waste liquid collection device 400; when the first spectrum detector 610 detects that the concentration of quantum dots is significantly increased, it indicates that the lower liquid phase is basically emptied, and the valve structure 500 can be controlled to realize the communication between the extraction device 200 and the concentration device 300.

[0046] The present application provides related components and connection relationships between components to realize full-automatic purification goals, for example, the valve structure 500 and the first spectrum detector 610 can detect the composition of the liquid phase, thereby helping to automatically collect the quantum dot solution after extraction, and helping to realize the automatic purification of quantum dots. The workers do not have to expose to the organic solvent environment, and the operation is safer.

[0047] The material adding device 100 can include a pump 110, for example, an HPLC (high performance liquid chromatography) pump, which can accurately control the amount of material added by controlling the pump speed and the sample adding time.

[0048] The extraction device 200 can be provided with a stirrer 210, so that the mixing of various materials is more sufficient, and the quantum dots and impurities are more fully dispersed in the corresponding solvent. The stirrer 210 can be a stirring rod inserted into the extraction device 200, and the head of the stirring rod can be provided with stirring blades. The stirrer 210 and the extraction device 200 can be sealingly connected.

[0049] The purification system can include a vacuum pump 700 for pumping the gaseous solvent in the concentration device 300, so as to realize further concentration after extraction. The vacuum pump 700 extracts the upper gas, and as the vacuum degree decreases, the solvent in the lower liquid will volatilize, volatilize to the upper layer to become gas and be extracted away. Illustratively, the gas in the upper layer can be continuously extracted until the last volume reaches the target volume, so that the quantum dot product can be concentrated, which is convenient for storage and transportation.

[0050] The concentration device 300 has a liquid level identification device for identifying the volume of the remaining material in the concentration device 300. This makes the degree of concentration the same each time, improving consistency. The liquid level identification device can be a liquid level sensor.

[0051] Further, the liquid level identification device can be a second spectrometer 620 configured to detect the absorbance at a predetermined liquid level to determine the height relationship between the actual liquid level and the predetermined liquid level. For example, concentration causes the liquid level to drop. When the actual liquid level is higher than the predetermined liquid level, the absorbance at the predetermined liquid level is large; when the actual liquid level is lower than the predetermined liquid level, the absorbance at the predetermined liquid level is small, so the height relationship between the actual liquid level and the predetermined liquid level can be obtained. For example, when the actual liquid level reaches the predetermined liquid level, the vacuum pump 700 can be stopped. Of course, the second spectrometer 620 can be replaced by a photometer.

[0052] The concentration device 300 can also be at least partially transparent, and the side wall can have scale lines. Alternatively, the concentration device 300 can be provided with an observation window to enable observation of the liquid level. Of course, the actual liquid level can also be monitored by scale lines or other forms of liquid level monitoring devices.

[0053] The purification system can also include a collection bottle 700 connected to the outlet of the concentration device 300. For example, when the quantum dot solution in the concentration device 300 is concentrated, it can be discharged to the collection bottle 700 to achieve collection of the extracted and concentrated quantum dots.

[0054] The purification system includes a gas addition device 800, which can include a gas source 801, a pressure reducing valve 802, a mass flow controller, etc. The gas addition device 800 includes an extraction device application end 810 for applying gas to the extraction device 200, so that the liquid in the extraction device 200 can be discharged under pressure. The gas source 801 can be high-purity nitrogen.

[0055] Further, the gas addition device 800 can also include a concentration device application end 820 for applying gas to the concentration device 300, so that the liquid in the concentration device 300 can be discharged under pressure. Of course, the extraction device application end 810 and the concentration device application end 820 can be provided with respective mass flow controllers (e.g., first mass flow controller 803 and second mass flow controller 804) to accurately control the pressure and flow of nitrogen and accurately discharge the liquid.

[0056] The way of flowing out of the liquid by the gas addition device 800 (rather than the external atmospheric pressure) can isolate water vapor and oxygen in the atmosphere, avoid deterioration of the quantum dots, and improve the purification effect.

[0057] The purification system can also include a computer. The aforementioned HPLC pump, stirrer 210, valve structure 500, mass flow controller, vacuum pump 700, etc., can be controlled by computer programs to achieve automated sample addition, extraction, concentration, and collection. The purification process for each batch of quantum dots is reproducible, ensuring high consistency. After a one-button start, the system automatically injects samples, automatically discharges waste liquid, automatically stirs, and automatically concentrates samples according to a pre-designed program, operating in a cyclical manner. This not only eliminates the physical labor of operating centrifuges and centrifuge tubes, protecting human health, but also eliminates the mental labor of operating the computer, truly saving labor costs.

[0058] The following describes the workflow of a purification system, using cadmium selenide quantum dots as an example:

[0059] (1) Add cadmium selenide quantum dot stock solution, a polar solvent, and a non-polar solvent to the extraction device 200. For example, the polar solvent may include methanol, and the non-polar solvent may include n-hexane and chloroform. The valve structure 500 is closed, the cadmium selenide stock solution and chloroform are mixed, the methanol and n-hexane are mixed, and then the mixture is added to the extraction device 200.

[0060] (2) The extraction device 200 separates the liquid phase into an upper liquid phase and a lower liquid phase. The upper liquid phase is a hydrocarbon-rich phase, a low-density phase, and a phase containing ions, which contains the useful substances. The lower liquid phase is an alcohol-rich phase, a high-density phase, and a phase containing impurities, which is the waste liquid. To facilitate separation, a small amount of chloroform can be added to adjust the density difference between the two liquid phases. It can be understood that the greater the density difference, the faster the separation.

[0061] (3) Gas injection and waste liquid discharge. Valve structure 500 points to the waste liquid collection device 400. High-purity nitrogen gas is injected into the extraction device 200 by the first mass flow controller 803 at a set flow rate and pressure, and the waste liquid is discharged. Figure 1 As shown, the three spaces divided by the two dashed lines within the extraction device 200 can represent the gas phase, the upper liquid phase, and the lower liquid phase, respectively. Until the first spectrometer 610 detects a significant increase in the quantum dot concentration, the valve structure 500 switches, discharging the liquid phase containing the quantum dots into the concentration device 300.

[0062] (4) Concentrating quantum dots. After the liquid phase containing the quantum dots is completely discharged into the concentration device 300, the valve structure 500 is closed again. The vacuum pump 700 is turned on to extract some solvent until the liquid level in the concentration device 300 reaches the preset level. The concentrated quantum dots are discharged into the collection bottle 700.

[0063] The advantages of the purification system provided in this application include:

[0064] (1) The adding amount of quantum dot stock solution, polar solvent and non-polar solvent can be accurately controlled by the flow rate of HPLC pump and the sampling time length. The pressure and flow rate of nitrogen can also be accurately controlled. The rotating speed of the stirrer 210 can also be accurately controlled. The running time length of the vacuum pump 700 can also be accurately controlled. The purification process of each batch of quantum dots can be completely replicated, thereby improving consistency.

[0065] (2) The system can automatically sample, automatically discharge waste liquid, automatically stir, automatically concentrate the sample and cyclically work according to the pre-designed program. Not only the physical labor of operating the centrifuge and centrifuge tube is protected, thereby protecting the health of the human body, but also the mental labor of operating the computer is not needed, thereby truly saving the labor cost.

[0066] (3) The quantum dots are always in the state of nitrogen protection, thereby eliminating the possible pollution caused by water vapor and oxygen.

[0067] The above describes the preferred embodiments of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A purification system, characterized in that, The purification system comprises: a material adding device; an extraction device, the material adding device being capable of adding a plurality of materials to the extraction device in a controlled manner; a concentration device, a waste liquid collecting device, and a valve structure, the concentration device and the waste liquid collecting device being connected to an outlet of the extraction device through the valve structure, the valve structure being configured to switch between the extraction device being communicated with the concentration device, being communicated with the waste liquid collecting device, and being communicated with neither; a first spectrum detector configured to detect spectrum information of materials flowing out of the outlet of the extraction device.

2. The purification system of claim 1, wherein, The extraction device is provided with a stirrer.

3. The purification system of claim 1, wherein, The purification system comprises a vacuum pump for pumping gaseous solvent in the concentration device.

4. The purification system of claim 1, wherein, The concentration device is provided with a liquid level identification device for identifying a liquid level of materials remaining in the concentration device.

5. The purification system of claim 4, wherein, The liquid level identification device is a second spectrum detector or a luminometer, the second spectrum detector and the luminometer being configured to detect absorbance at a predetermined liquid level to determine a height relationship between the liquid level of the materials remaining and the predetermined liquid level; and / or, the liquid level identification device is a liquid level sensor.

6. The purification system of claim 1, wherein, The concentration device is at least partially transparent, and the concentration device is provided with a scale line.

7. The purification system of claim 1, wherein, The concentration device is provided with an observation window for observing the liquid level.

8. The purification system of any one of claims 1 to 7, wherein, The purification system further comprises a collecting bottle connected to an outlet of the concentration device.

9. The purification system of any one of claims 1 to 7, wherein, The purification system comprises a gas adding device, the gas adding device comprising an extraction device applying end for applying gas to the extraction device, so that liquid in the extraction device can be discharged under pressure.

10. The purification system of any one of claims 1 to 7, wherein, The purification system comprises a gas adding device, the gas adding device comprising a concentration device applying end for applying gas to the concentration device, so that liquid in the concentration device can be discharged under pressure.

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