Purification device

Abstract

The present application provides a purification device. The purification device comprises a conveying mechanism and a material feeding mechanism. The conveying mechanism comprises a conveying part used for conveying materials, the conveying part comprises a separation membrane, in the height direction, the liquid materials can penetrate through the separation membrane downwards, and the solid materials can be reserved on the separation membrane and advance along with the separation membrane. The material feeding mechanism is arranged in the advancing direction of the conveying part, comprises a plurality of material adding parts which are sequentially arranged and is used for feeding materials to the conveying part. Compared with an intermittent purification device, the separation membrane provided by the utility model has the advantages that on one hand, solid and liquid separation can be realized, and on the other hand, materials can be transferred and circularly moved, so that quantum dot purification steps such as deposition, cleaning and redissolution can be continuously carried out, and the purification efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of quantum dot purification, and in particular to a purification device. Background Art

[0002] In the quantum dot stock solution, in addition to quantum dots, there are unreacted precursors, solvents, etc. The traditional method for purifying quantum dots is to place the suspension obtained by mixing the stock solution with a poor solvent in a centrifuge tube, centrifuge and sediment it with a common commercial centrifuge, and then redissolve it with a good solvent to obtain quantum dots with higher purity. The volumes of the quantum dot stock solution, the poor solvent, and the good solvent, as well as the rotation speed and centrifugation duration of the centrifuge, need to be precise, otherwise problems may occur in the consistency of the purified quantum dots. Throughout the process, operators need to operate patiently, the work is repetitive and cumbersome, and the personnel are exposed to an organic solvent environment.

[0003] Chinese Patent with the authorization announcement number CN112760091B discloses a method for purifying quantum dots, which utilizes the principle that the solubilities of quantum dots and impurities in a specific solvent are different and adopts a centrifugation method to purify quantum dots. In addition, the purification process needs to be carried out intermittently, and the purification efficiency needs to be improved.

[0004] Therefore, there is room for improvement in the purification method of quantum dots. Summary of the Utility Model

[0005] In order to solve or alleviate at least one problem mentioned in the background art, the present application provides a purification device.

[0006] The purification device provided by the embodiment of the present application includes:

[0007] A conveying mechanism, the conveying mechanism includes a conveying part for transporting materials, the conveying part includes a separation membrane, in the height direction, the materials in the form of liquid can pass downward through the separation membrane, and the materials in the form of solid can be retained on the separation membrane and travel with the separation membrane;

[0008] A material feeding mechanism, along the traveling direction of the conveying part, the material feeding mechanism includes a plurality of material adding parts arranged in sequence for feeding materials to the conveying part.

[0009] In at least one embodiment, the conveying part transports the materials in a straight line, the separation membrane includes an upper conveying area and a lower conveying area that are connected end to end and circulate, the material adding part is used to add the materials to the upper conveying area, and a collecting device is arranged between the upper conveying area and the lower conveying area to collect the materials passing through the upper conveying area.

[0010] In at least one embodiment, the conveying mechanism includes a plurality of forward partitions arranged at intervals along the traveling direction of the conveying part. In the height direction, there is a spacing between the forward partition and the separation membrane, and the spacing is not greater than 5 mm, so that the plurality of forward partitions and the conveying part form a plurality of regions arranged side by side in the traveling direction of the conveying part.

[0011] In at least one embodiment, lateral partitions are provided on both side surfaces of the conveying part perpendicular to the traveling direction to prevent the material from flowing out of the conveying part from both side surfaces. The conveying mechanism includes a plurality of forward partitions arranged along the traveling direction of the conveying part. The forward partitions are connected to the lateral partitions, and there is a spacing between the forward partitions and the separation membrane, and the spacing is not greater than 1 mm.

[0012] In at least one embodiment, in the traveling direction of the conveying part, the material adding part sequentially includes:

[0013] A mixed liquid adding part for adding a mixed material to be purified and a precipitant to the separation membrane;

[0014] A first solvent adding part for adding a first solvent to the separation membrane;

[0015] A second solvent adding part for adding a second solvent to the separation membrane.

[0016] In at least one embodiment, the material adding part further includes a third solvent adding part, and the third solvent adding part is arranged downstream of the second solvent adding part. The third solvent adding part is used for adding a third solvent to the separation membrane; and / or, a drying part is arranged between the first solvent adding part and the second solvent adding part, and the drying part is used for drying the material.

[0017] In at least one embodiment, a shower nozzle is arranged at the outlet end of the material adding part, and the material is sprayed on the surface of the separation membrane through the shower nozzle.

[0018] In at least one embodiment, in the horizontal direction, the conveying part transports the material along an annular line, and the separation membrane includes a plurality of sub-membranes spaced apart on the annular line.

[0019] In at least one embodiment, the purification device includes a plurality of split tanks. The split tanks include a feed tank and a discharge tank arranged on both sides of the sub-membrane in the height direction. The feed tank and the discharge tank are configured to be able to move towards each other and away from each other. The material adding part feeds the material to the sub-membrane through the feed tank, and the material passing through the sub-membrane is discharged through the discharge tank.

[0020] In at least one embodiment, the purification device includes a control device configured to control the traveling speed of the conveying part and the material feeding flow rate of the material feeding mechanism.

[0021] Compared with the intermittent purification device, on the one hand, the separation membrane of the present application can separate solids from liquids, and on the other hand, it can transfer materials and move cyclically, enabling continuous progress of quantum dot purification steps such as deposition, cleaning, and redissolution, thereby improving the purification efficiency. Brief Description of the Drawings

[0022] Figure 1 Shows a schematic structural diagram of a purification device according to an embodiment of the present application.

[0023] Figure 2 Shows a schematic structural diagram of the conveying part of a purification device according to another embodiment of the present application.

[0024] Figure 3 Shows a schematic flow diagram of the purification steps of a purification device according to an embodiment of the present application.

[0025] Figure 4 Shows a schematic structural diagram of a split tank of a purification device according to an embodiment of the present application.

[0026] Figure 5 Shows a diagram of the regional positional relationship in a split tank of a purification device according to an embodiment of the present application.

[0027] Description of the Reference Numerals

[0028] 100 Conveying mechanism; 110 Conveying part; 111 Separation membrane; 120 Upper conveying area; 130 Lower conveying area; 140 Forward partition; 150 Lateral partition; 160 Driving roller;

[0029] 200 Material feeding mechanism; 210 Material adding part; 211 Mixed liquid adding part; 212 First solvent adding part; 2121 Quantum dot stock solution; 2122 Chloroform; 2123 Ethanol; 2124 Acetone; 213 Second solvent adding part; 214 Third solvent adding part; 215 Three-way valve; 220 Drying part; 221 Gas mass flow controller; 222 Pressure reducing valve; 223 Gas source; 230 Shower nozzle;

[0030] 300 Collection device; 310 First waste liquid collection box; 320 Second waste liquid collection box; 330 Third waste liquid collection box;

[0031] 400 Pump;

[0032] 510 Precipitation area; 520 Cleaning area; 530 Drying area; 540 Redissolution area; 550 Regenerative cleaning area;

[0033] 600 Control device;

[0034] 700 Turntable; 710 Sub-membrane; 720 Split tank body; 721 Feed tank body; 722 Discharge tank body Detailed implementation manners

[0035] The exemplary implementation manners of the present application will be described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, rather than to exhaust all feasible manners of the present application, nor to limit the scope of the present application.

[0036] The implementation manner of the present application provides a purification device. Refer to Figure 1 , the purification device may include a conveying mechanism 100 and a material feeding mechanism 200.

[0037] The conveying mechanism 100 may include a conveying part 110 for transporting materials. The conveying part 110 may include a separation membrane 111. In the height direction h, the material in the form of liquid passes downward through the separation membrane 111, and the material in the form of solid remains on the separation membrane 111 and travels with the separation membrane 111. Exemplarily, the pore size of the separation membrane 111 may be 50 μm.

[0038] Along the traveling direction of the conveying part 110, the material feeding mechanism 200 includes a plurality of material adding parts 210 arranged in sequence for feeding corresponding materials to the conveying part 110.

[0039] The solubility of quantum dots and impurities in a specific polar mixed solvent is different. For example, quantum dots can precipitate in a poor solvent and dissolve in a good solvent. By the cooperation of the separation membrane 111 and the solvent, quantum dots can be screened out, improving the purity of quantum dots (specific purification steps are shown later). Compared with the intermittent purification device, the separation membrane 111 in the conveying system provided by the present application can, on the one hand, achieve solid-liquid separation, and on the other hand, transfer materials and move cyclically, enabling continuous progress of quantum dot purification steps such as deposition, cleaning, and redissolution, improving the purification efficiency.

[0040] In an implementation manner of the present application, refer to Figure 1 , the conveying part 110 may be formed into a linear conveyor belt type transfer device. The conveying part 110 transports materials along a straight line, for example, transports materials in the left-right direction in the figure. The separation membrane 111 may include an upper conveying area 120 and a lower conveying area 130 that are connected end to end and travel cyclically. The material adding part 210 adds materials to the upper conveying area 120. A collecting device 300 may be provided between the upper conveying area 120 and the lower conveying area 130 to collect the materials passing through the separation membrane 111.

[0041] In an embodiment of the present application, the conveying mechanism 100 includes a plurality of forward partitions 140 arranged at intervals along the traveling direction of the conveying part 110. A spacing a can be provided between the forward partition 140 and the separation membrane 111, and the spacing a can be no greater than 5 mm, preferably no greater than 1 mm, so that the plurality of forward partitions 140 and the conveying part 110 are combined to form a plurality of regions (such as a precipitation area 510, a cleaning area 520, a drying area 530, a reconstitution area 540, and a regeneration cleaning area 550) arranged side by side in the traveling direction of the conveying part 110. On the one hand, the forward partition 140 can prevent the undesired cross-border and mixing of the materials added by adjacent material adding parts 210; on the other hand, when solid materials accumulate on the surface of the separation membrane 111, it may affect the effects of processes such as cleaning and reconstitution. The forward partition 140 can play a scraping role, scraping the accumulated solids into a filter cake with a thickness not exceeding its interval a (such as 1 mm), enabling the solvent to quickly dissolve the materials and improving the effects of processes such as cleaning and reconstitution.

[0042] In an embodiment of the present application, lateral partitions 150 are provided on both side surfaces of the conveying part 110 perpendicular to its traveling direction. The lateral partitions 150 can abut against the sides of the conveying part 110 to prevent the materials on the conveying part 110 from flowing out of the conveying part 110 from both side surfaces. The forward partition 140 can be connected to the lateral partition 150, and the distance between the forward partition 140 and the separation membrane 111 can be controlled by the relative position of the lateral partition 150 and the conveying mechanism 100.

[0043] In an embodiment of the present application, referring to Figure 1 , the conveying mechanism 100 may include a driving roller 160 for providing power. Exemplarily, the conveying mechanism 100 may include two driving rollers 160, and the conveying part 110 is sleeved on the driving rollers 160 and moves synchronously with the driving rollers 160. In one example, one of the two driving rollers 160 is a driving roller, and the other is a follower roller.

[0044] In an embodiment of the present application, in the traveling direction of the conveying part 110, the material adding part 210 sequentially includes a mixed liquid adding part 211, a first solvent adding part 212, and a second solvent adding part 213.

[0045] The mixed liquid adding part 211 is used to add a mixed material to be purified (such as a quantum dot stock solution 2121) and a precipitant to the separation membrane 111. Exemplarily, the precipitant may include one or more of chloroform 2122, ethanol 2123, and acetone 2124. The quantum dot stock solution 2121 and chloroform 2122 can be first mixed to form a first mixed liquid, ethanol 2123 and acetone 2124 can be mixed to form a second mixed liquid, and then the first mixed liquid and the second mixed liquid are mixed. The mixing ratio can be controlled by a three-way valve 215.

[0046] The first solvent addition part 212 is used to add the first solvent to the separation membrane 111. Exemplarily, the first solvent can be ethanol, which is used as a poor solvent to dissolve impurities other than quantum dots.

[0047] The second solvent addition part 213 is used to add the second solvent to the separation membrane 111. Exemplarily, the second solvent can be chloroform, which is used as a good solvent to redissolve quantum dots.

[0048] In an embodiment of the present application, the material addition part 210 further includes a third solvent addition part 214. The third solvent addition part 214 is arranged downstream of the second solvent addition part 213. The third solvent addition part 214 is used to add a third solvent such as n - hexane to the separation membrane 111, so that the conveying part 110 can be cleaned again for reuse.

[0049] In an embodiment of the present application, a drying part 220 is arranged between the first solvent addition part 212 and the second solvent addition part 213. The drying part 220 is used to blow dry the material (quantum dots) and efficiently discharge waste liquids such as ethanol. The drying part 220 can include a pressure reducing valve 222 and a gas mass flow controller 221 for precisely controlling the gas ejection amount. The drying part 220 can include a gas source 223 or be connected to the gas source 223. The gas source 223 can be high - purity nitrogen. Of course, the gas source 223 can also be other inert gases.

[0050] In an embodiment of the present application, collection devices 300 can be respectively arranged below each area according to the positions of the precipitation area 510, the cleaning area 520, the drying area 530, the redissolution area 540, and the regeneration cleaning area 550, or the number of collection devices 300 can be reduced by classifying according to the types of liquids. Exemplarily, see Figure 1 , in sequence, the collection device 300 can include a first waste liquid box 310, a quantum dot collection box 320, and a second waste liquid box 330. The first waste liquid box 310 is used to collect waste liquids generated in the precipitation area 510, the cleaning area 520, and the drying area 530. The quantum dot collection box 320 is used to collect redissolved quantum dots. The second waste liquid box 330 is used to collect waste liquids generated in the regeneration cleaning area 550.

[0051] In an embodiment of the present application, the material addition part 210 includes a shower - type nozzle 230, and the material is sprayed on the surface of the separation membrane 111 through the shower - type nozzle 230. The shower - type nozzle 230 can expand the spraying area to make the material contact more fully.

[0052] In an embodiment of the present application, the purification device can include a pump 400, which can be a peristaltic pump, and thus the addition amount of each material can be precisely controlled through the peristaltic pump.

[0053] In one embodiment of the present application, the purification device may include a control device 600, which is configured to be able to control the traveling speed of the conveying unit 110 and the material feeding flow rate of the material feeding mechanism 200. For example, the control device may control the pump 400, the three-way valve 215, the gas mass flow controller 221, and the power mechanism (such as a motor) of the driving roller 160. For example, a control program can be edited through software to achieve precise control of parameters such as liquid flow rate, gas flow rate, and rotation speed of the driving roller 160, so that the purification step can be carried out precisely, making the purification process of each batch of quantum dots reproducible and having a high degree of consistency.

[0054] Next, the present application provides an embodiment of purifying quantum dots by a purification device. The quantum dots may be cadmium selenide. The driving roller 160 can be controlled to rotate at a constant speed, driving the conveying unit 110 to pass through the precipitation area 510, the cleaning area 520, the drying area 530, the redissolution area 540, and the regeneration cleaning area 550 at a constant speed. The pump 400 and the gas mass flow controller 221 are controlled to continuously operate, continuously adding corresponding materials to the conveying unit 110 and performing the drying process to continuously purify the quantum dots online. Of course, when only purifying some quantum dots, the start and stop times of the equipment in each area can be controlled. For example, the precipitation area 510 is filled with materials first, and the equipment in each area is turned on in sequence when the materials reach the cleaning area 520, the drying area 530, the redissolution area 540, and the regeneration cleaning area 550.

[0055] See Figure 3 , the purification process of each area may include the following steps.

[0056] (S1) Precipitation. In the precipitation area 510, the suspension formed by mixing the quantum dot stock solution and the precipitant is filtered by the separation membrane 111, the solid moves with the separation membrane 111 to the cleaning area 520, and the liquid passes through the separation membrane 111 and enters the collection device 300.

[0057] (S2) Cleaning. In the cleaning area 520, the first solvent adding part 212 adds ethanol to the separation membrane 111. Ethanol, as a poor solvent, can dissolve impurities but not dissolve quantum dots, so that among the solid substances (quantum dots and impurities) screened out in step S1, the quantum dots move with the separation membrane 111 to the drying area 530, and the impurities form a liquid and pass through the separation membrane 111 and enter the collection device 300.

[0058] (S3) Drying. In the drying area 530, the drying part 220 blows out high-purity nitrogen to dry the residual ethanol on the quantum dots, and the dry solid quantum dots are left on the separation membrane 111, and the solid quantum dots move with the separation membrane 111 to the redissolution area 540.

[0059] (S4) Re-dissolution. In the re-dissolution zone 540, the second solvent addition part 213 adds chloroform to the separation membrane 111. After the quantum dots are dissolved in chloroform, they pass through the separation membrane 111 and enter the collection device 300, obtaining quantum dots with higher purity.

[0060] (S5) Regeneration cleaning. In the regeneration cleaning zone 550, the third solvent addition part 214 adds n-hexane to the separation membrane 111. After the residual quantum dots and / or other impurities are dissolved in n-hexane, they pass through the separation membrane 111 and enter the collection device 300, so that the separation membrane 111 is cleaned, and then can enter the precipitation zone 510, the cleaning zone 520... again with the driving roller 160, realizing recycling and making the purification process continuous.

[0061] After the purification device is started, it automatically samples, automatically discharges waste liquid, automatically collects samples, and works in a cycle according to a pre-designed program. It not only eliminates the physical labor of operating a centrifuge and centrifuge tubes by humans, protecting human health, but also eliminates the mental labor of operating a computer by humans, truly saving labor costs.

[0062] In addition, in an embodiment of the present application, in the horizontal direction, the conveying part 110 can transport materials along a circular line (such as a closed ring like a perfect circle or an ellipse), and the separation membrane 111 includes a plurality of sub-membranes 710 spaced apart on the circular line. Refer to Figure 2 , the conveying part 110 can be formed as a turntable 700, and the separation membrane 111 can include a plurality of sub-membranes 710 spaced apart on the turntable (the sub-membrane can be understood as a smaller piece of membrane relative to a larger piece of membrane). The centers of the plurality of sub-membranes 710 can be on the same circle with the center of the turntable 700 as the center. Further, refer to Figure 4 , the purification device can include a plurality of split tanks 720. The split tanks 720 include a feed tank 721 and a discharge tank 722 disposed on both sides of the sub-membrane 710 in the height direction h. The feed tank 721 and the discharge tank 722 are configured to be able to move towards and away from each other. The material addition part 210 feeds materials into the sub-membrane 710 through the feed tank 721, and the materials passing through the sub-membrane 710 are discharged through the discharge tank 722. It can be understood that the split tanks 720 play the same role as the forward partition 140 and the lateral partition 150, and can prevent the undesired cross-border and mixing of materials added by adjacent material addition parts 210.

[0063] Refer to Figure 5 , the split tanks can be arranged to be spaced apart on the circular line. When the turntable 700 rotates to a certain position, the split tanks 720 can correspond to the position of the sub-membrane 710. The split tanks 720 can correspond to the aforementioned precipitation zone 510, cleaning zone 520, drying zone 530, re-dissolution zone 540, and regeneration cleaning zone 550.

[0064] The aforementioned control device 600 can be configured to control the start and stop time of the turntable 700, the rotation speed, and the moving speed and distance of the feed tank 721 and the discharge tank 722. For example, it can be realized that after the turntable 700 rotates to a certain position, it stops rotating, and the feed tank 721 and the discharge tank 722 move towards each other to clamp the sub-membrane 710. After corresponding purification steps are implemented in the feed tank 721 and the discharge tank 722, the feed tank 721 and the discharge tank 722 move away from each other, and the turntable continues to rotate, driving the sub-membrane 710 to the next working station.

[0065] Of course, the automated purification process of quantum dots can be specifically optimized in combination with a specific quantum dot system. The purification device provided in this application is not limited to purifying quantum dots and can be used for online purification of other materials.

[0066] The purification device provided in this application provides new solid-liquid separation, cleaning, and re-dissolution technologies and realizes automation on this basis, improving the purification efficiency and consistency of quantum dots. Operators do not have to often come into contact with chemical reagents, reducing potential risks.

[0067] The above are the preferred embodiments of this application. It should be noted that for those skilled in the art, without departing from the principle of this application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this application.

Claims

1. A purification device, characterized in that, Comprising: A conveying mechanism, the conveying mechanism includes a conveying part for conveying materials, the conveying part includes a separation membrane, in the height direction, the material formed as a liquid can pass downward through the separation membrane, and the material formed as a solid can remain on the separation membrane and travel with the separation membrane; A material feeding mechanism, along the traveling direction of the conveying part, the material feeding mechanism includes a plurality of material adding parts arranged in sequence for feeding materials to the conveying part.

2. The purification device according to claim 1, characterized in that, The conveying part conveys the materials in a straight line, the separation membrane includes an upper conveying area and a lower conveying area that are connected end to end and circulate, the material adding part is used to add the materials to the upper conveying area, and a collecting device is arranged between the upper conveying area and the lower conveying area to collect the materials passing through the upper conveying area.

3. The purification device according to claim 1, wherein, The conveying mechanism includes a plurality of forward partitions arranged at intervals along the traveling direction of the conveying part. In the height direction, there is a gap between the forward partition and the separation membrane, and the gap is not greater than 5 mm, so that the plurality of forward partitions and the conveying part form a plurality of regions arranged side by side in the traveling direction of the conveying part.

4. The purification device according to claim 1, characterized in that Lateral partitions are arranged on both side surfaces of the conveying part perpendicular to the traveling direction to prevent materials from flowing out of the conveying part from both side surfaces of the conveying part. The conveying mechanism includes a plurality of forward partitions arranged along the traveling direction of the conveying part. The forward partitions are connected to the lateral partitions, and there is a gap between the forward partitions and the separation membrane, and the gap is not greater than 1 mm.

5. The purification device according to claim 1, characterized in that In the traveling direction of the conveying part, the material adding part sequentially includes: A mixed liquid adding part for adding a mixed material to be purified and a precipitant to the separation membrane; A first solvent adding part for adding a first solvent to the separation membrane; A second solvent adding part for adding a second solvent to the separation membrane.

6. The purification device according to claim 5, wherein The material adding part further includes a third solvent adding part, the third solvent adding part is arranged downstream of the second solvent adding part, and the third solvent adding part is used to add a third solvent to the separation membrane; and / or, a drying part is arranged between the first solvent adding part and the second solvent adding part, and the drying part is used to blow dry the materials.

7. The purification device according to claim 1, characterized in that, A shower nozzle is arranged at the outlet end of the material adding part, and the materials are sprayed on the surface of the separation membrane through the shower nozzle.

8. The purification device according to claim 1, wherein In the horizontal direction, the conveying part conveys the materials along an annular line, and the separation membrane includes a plurality of sub-membranes distributed at intervals on the annular line.

9. The purification device according to claim 8, characterized in that, The purification device includes a plurality of split tanks, the split tanks include a feed tank and a discharge tank arranged on both sides of the sub-membrane in the height direction, the feed tank and the discharge tank are configured to be able to move towards each other and away from each other, the material adding part feeds materials to the sub-membrane through the feed tank, and the materials passing through the sub-membrane are discharged through the discharge tank.

10. The purification device according to any one of claims 1 to 9, characterized in that, The purification device includes a control device, and the control device is configured to be able to control the traveling speed of the conveying part and the material feeding flow rate of the material feeding mechanism.

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