A nanofiltration-electrodialysis coupling device for separating ADP from phosphate and application thereof

Abstract

The application relates to a nanofiltration-electrodialysis coupling device for separating ADP and phosphate and application thereof, and the nanofiltration-electrodialysis coupling device is an electrodialyzer with inserted organic nanofiltration membranes, and comprises a membrane stack composed of at least two separation units; each separation unit comprises a first ion exchange membrane assembly, a first organic nanofiltration membrane assembly, a second organic nanofiltration membrane assembly and a second ion exchange membrane assembly which are sequentially and parallelly arranged. The nanofiltration-electrodialysis coupling device can separate charged target products from salts, realizes efficient separation of the charged target products, and can be used for separating charged substances from salts in a mixed system, especially provides a new method for separating and purifying the cofactor ADP in a multi-enzyme catalytic system synthesis system, the recovery rate level is very considerable, and the salt removal effect is also very good.

Description

Technical Field

[0001] This invention belongs to the field of industrial biotechnology and relates to a nanofiltration-electrodialysis coupling device for separating ADP and phosphate and its application in the separation and recovery of ADP and phosphate. Background Technology

[0002] The core of cell-free synthetic biology lies in the in vitro construction of multi-enzyme catalytic systems. Mimicking in vivo metabolic pathways, a series of enzymes and coenzymes are combined in vitro to form a complex biochemical metabolic network to obtain the target product. A challenge in cell-free in vitro multi-enzyme synthesis lies in the reuse of cofactors. ATP, as one of the two most common cofactors, participates in most enzymatic reactions. Expensive cofactors increase production costs. If the cofactor ADP (adenosine diphosphate) in the conversion solution system can be separated, purified, and regenerated to synthesize ATP (adenosine triphosphate), production costs can be significantly reduced. Furthermore, high concentrations of phosphate also inhibit the enzyme activity of multi-enzyme systems. Therefore, the separation of ADP and phosphate is crucial for multi-enzyme catalytic systems.

[0003] Electrodialysis is a commonly used desalination device in membrane separation. However, when the target product is charged, it will pass through the cation and anion exchange membrane along with the impurities during electrodialysis, leading to product loss or even ineffective separation from the impurities. Conventional electrodialysis desalination devices cannot separate the charged target product from the salt.

[0004] CN 216024146 U discloses an electrodialysis desalination device for amino acid separation. The amino acid stock solution enters the dialysis tank, where an ion exchange membrane separates it into a cation solution and an anion solution. This allows for rapid separation of cations and anions as the amino acid stock solution enters the dialysis tank, fundamentally reducing salt formation. Amino acids are electrically neutral in solution at their isoelectric point, but as electrodialysis proceeds, the pH of the solution changes, causing the amino acids to migrate due to their charge.

[0005] Therefore, it is necessary to develop an apparatus and method for separating ADP and phosphate to overcome the shortcomings of conventional electrodialysis operations, which result in the loss of the target product due to the charged migration of the target product into the concentration chamber. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a nanofiltration-electrodialysis coupling device for separating ADP and phosphate and its application in the separation and recovery of ADP and phosphate.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a nanofiltration-electrodialysis coupling device for separating ADP and phosphate, wherein the nanofiltration-electrodialysis coupling device is an electrodialyzer with an inserted organic nanofiltration membrane, comprising a membrane stack consisting of at least two separation units; each separation unit comprises a first ion exchange membrane assembly, a first organic nanofiltration membrane assembly, a second organic nanofiltration membrane assembly, and a second ion exchange membrane assembly arranged in parallel in sequence. A schematic diagram is shown below. Figure 1 As shown.

[0009] The nanofiltration-electrodialysis coupling device involved in this invention can separate charged target products from salt, achieving efficient separation of charged target products. This device and its usage method can be used to separate charged substances and salt in a mixed system, especially providing a new method for the separation and purification of cofactor ADP in multi-enzyme catalytic synthesis systems. Its recovery rate is very impressive, and its salt removal effect is also very good.

[0010] Preferably, the number of separation units is 3-9, for example 3, 4, 5, 6, 7, 8 or 9, preferably 3-6.

[0011] Preferably, the first ion exchange membrane assembly is selected from a single anion exchange membrane, a single cation exchange membrane, or an anion exchange membrane and a cation exchange membrane arranged in alternating parallel configurations;

[0012] The second ion exchange membrane assembly is selected from a single anion exchange membrane, a single cation exchange membrane, or anion exchange membranes and cation exchange membranes arranged in alternating parallel configurations;

[0013] Furthermore, the first ion exchange membrane assembly and the second ion exchange membrane assembly together constitute 1-3 pairs (e.g., 1 pair, 2 pairs or 3 pairs) of anion and cation exchange membranes.

[0014] Preferably, the first organic nanofiltration membrane assembly comprises 1-3 (e.g., 1, 2 or 3) organic nanofiltration membrane sheets arranged in parallel;

[0015] Preferably, the second organic nanofiltration membrane assembly comprises 1-3 (e.g., 1, 2 or 3) organic nanofiltration membrane sheets arranged in parallel.

[0016] Preferably, the organic nanofiltration membrane is made of materials independently selected from cellulose acetate, polyamide, sulfonated polysulfone, sulfonated polyethersulfone, polyethersulfone, polyacrylonitrile, or polyvinylidene fluoride; more preferably, polyamide, polyethersulfone, or polyvinylidene fluoride.

[0017] Compared to other materials, choosing polyamide, polyethersulfone, or polyvinylidene fluoride as the material for organic nanofiltration membranes results in superior separation performance.

[0018] Preferably, the molecular weight cutoff of each organic nanofiltration membrane is independently selected from 100-1000 Da, such as 100 Da, 200 Da, 300 Da, 400 Da, 500 Da, 600 Da, 700 Da, 800 Da, 900 Da, 1000 Da, etc., and more preferably 400-1000 Da.

[0019] Preferably, each of the anion exchange membranes is independently selected from polyacrylic acid exchange membranes, quaternized polyarylether sulfone exchange membranes, polybenzimidazole ion exchange membranes, or polyvinyl alcohol ion exchange membranes; more preferably, quaternized polyarylether sulfone exchange membranes or polyvinyl alcohol ion exchange membranes.

[0020] Compared to other anion exchange membranes, the separation effect of the device is superior when quaternized polyarylether sulfone exchange membranes and polyvinyl alcohol ion exchange membranes are selected as anion exchange membranes.

[0021] Preferably, each of the cation exchange membranes is independently selected from perfluorosulfonic acid ion exchange membranes, perfluorocarboxylic acid ion exchange membranes, polybenzimidazole ion exchange membranes, or polyvinyl alcohol ion exchange membranes; more preferably, perfluorosulfonic acid ion exchange membranes or polyvinyl alcohol ion exchange membranes.

[0022] Compared to other cation exchange membranes, the separation effect of the device is better when perfluorosulfonic acid ion exchange membranes and polyvinyl alcohol ion exchange membranes are selected as cation exchange membranes.

[0023] Secondly, the present invention provides a method for separating ADP and phosphate, wherein the method is performed using the nanofiltration-electrodialysis coupling device described in the first aspect, and specifically includes the following steps:

[0024] A mixture containing ADP and phosphate is circulated into and out of the dilute chamber between the first organic nanofiltration membrane module and the second organic nanofiltration membrane module. A low-concentration phosphate solution is simultaneously circulated into and out of the concentrate chamber between the first ion exchange membrane module and the first organic nanofiltration membrane module, as well as the concentrate chamber between the second ion exchange membrane module and the second organic nanofiltration membrane module. After the treatment is completed, ADP concentrate is output from the dilute chamber.

[0025] In the nanofiltration-electrodialysis coupling device involved in this invention, all membranes are arranged in parallel to each other. The space between the first organic nanofiltration membrane module and the second organic nanofiltration membrane module is designated as the dilute chamber, the space between the first ion exchange membrane module and the first organic nanofiltration membrane module is designated as the concentrate chamber, and the space between the second organic nanofiltration membrane module and the second ion exchange membrane module is also designated as the concentrate chamber.

[0026] When the mixture containing ADP and phosphate enters the dilute chamber, ADP cannot pass through the nanofiltration membrane, while phosphate can. Therefore, ADP concentrate is recovered from the dilute chamber. Furthermore, the phosphate cations can pass through the anion exchange membrane, and the anions can pass through the cation exchange membrane, so alkaline solution, phosphoric acid solution, and phosphate concentrate can be recovered separately.

[0027] Preferably, the nanofiltration-electrodialysis coupling device operates in constant current electrodialysis or constant voltage electrodialysis.

[0028] Preferably, the voltage of the nanofiltration-electrodialysis coupling device is set to 5-30V, such as 5V, 8V, 10V, 12V, 15V, 20V, 25V, 30V, etc., more preferably 10-20V.

[0029] Preferably, the current of the nanofiltration-electrodialysis coupling device is set to 10-30 mA / cm. 2 For example, 10mA / cm 2 12mA / cm 2 15mA / cm 2 18mA / cm 2 20mA / cm 2 22mA / cm 2 25mA / cm 2 30mA / cm 2 More preferably 10-20 mA / cm 2 .

[0030] Preferably, the flow rate of the dilute liquid is 0.2-0.6 L / min, such as 0.2 L / min, 0.3 L / min, 0.4 L / min, 0.5 L / min, 0.6 L / min, etc., and more preferably 0.4-0.6 L / min.

[0031] Preferably, the flow rate of the concentrate is 0.2-0.6 L / min, such as 0.2 L / min, 0.3 L / min, 0.4 L / min, 0.5 L / min, 0.6 L / min, etc., and more preferably 0.4-0.6 L / min.

[0032] Preferably, the concentration of the low-concentration phosphate solution is 0.1-0.8M, such as 0.1M, 0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M, 0.8M, etc.

[0033] Other specific point values ​​within the above numerical ranges can be selected, all of which are within the protection scope of this invention. Due to space limitations, they will not be described in detail here.

[0034] Thirdly, the present invention provides the application of the nanofiltration-electrodialysis coupling device described in the first aspect or the method described in the second aspect in the separation of charged compounds and salts.

[0035] Fourthly, the present invention provides the application of the nanofiltration-electrodialysis coupling device described in the first aspect or the method described in the second aspect in the recovery of ADP from a cell-free in vitro multi-enzyme catalytic conversion solution.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The nanofiltration-electrodialysis coupling device involved in this invention can separate charged target products from salt, achieving efficient separation of charged target products. This device and its usage method can be used to separate charged substances and salt in a mixed system, especially providing a new method for the separation and purification of cofactor ADP in multi-enzyme catalytic synthesis systems. Its recovery rate is very impressive, and its salt removal effect is also very good. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the membrane stack in the nanofiltration-electrodialysis coupling device involved in this invention. Detailed Implementation

[0039] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0040] Example 1

[0041] This embodiment provides a nanofiltration-electrodialysis coupling device, which includes four separation units. Each separation unit contains two organic nanofiltration membranes, both made of polyethersulfone with a molecular weight cutoff of 400-500. Each organic nanofiltration membrane has one anion exchange membrane and one cation exchange membrane disposed on its two sides. The anion exchange membrane is a polyvinyl alcohol ion exchange membrane, and the cation exchange membrane is a perfluorosulfonic acid ion exchange membrane. The four separation units form a complete membrane stack, as shown in the schematic diagram below. Figure 1 As shown.

[0042] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, as follows:

[0043] A mixed solution of 1 mM ADP and 10 g / L sodium phosphate was pumped into the dilute chamber of the nanofiltration-electrodialysis device, while a 0.3 M phosphate solution was pumped into the concentrate chambers on both sides of the dilute chamber. The device was operated under constant pressure at 10 V, with a flow rate of 0.4 L / min for both the dilute and concentrate chambers. After 4.5 h of treatment, a concentrated solution containing ADP was obtained from the dilute chamber solution.

[0044] The test results showed that the phosphate removal rate was 43.56% and the ADP recovery rate was 88.69%.

[0045] Example 2

[0046] This embodiment provides a nanofiltration-electrodialysis coupling device, which includes three separation units. Each separation unit includes two organic nanofiltration membranes, both made of polyethersulfone with a molecular weight cutoff of 500-600. Each organic nanofiltration membrane has a pair of alternating anion and cation exchange membranes on both sides. The anion exchange membrane is a polyvinyl alcohol ion exchange membrane, and the cation exchange membrane is a polyvinyl alcohol ion exchange membrane. The three separation units form a complete membrane stack.

[0047] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, as follows:

[0048] A mixed solution of 1 mM ADP and 10 g / L sodium phosphate was pumped into the dilute chamber of the nanofiltration-electrodialysis device, while a 0.2 M phosphate solution was pumped into the concentrate chambers on both sides of the dilute chamber. The device was operated under constant pressure at 20 V, with a flow rate of 0.6 L / min in both the dilute and concentrate chambers. After 3 hours of treatment, a concentrated solution containing ADP was obtained from the dilute solution.

[0049] The test results showed that the phosphate removal rate was 45.26% and the ADP recovery rate was 85.36%.

[0050] Example 3

[0051] This embodiment provides a nanofiltration-electrodialysis coupling device, which includes 6 separation units. Each separation unit includes 2 organic nanofiltration membranes, both made of polyamide with a molecular weight cutoff of 700-800. On each side of the organic nanofiltration membrane, there is a pair of alternating anion and cation exchange membranes, wherein the anion exchange membrane is a quaternized polyarylene ether sulfone ion exchange membrane and the cation exchange membrane is a perfluorosulfonic acid ion exchange membrane. The 6 separation units form a complete membrane stack.

[0052] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, as follows:

[0053] A mixed solution with an initial concentration of 1 mM ADP and 10 g / L sodium phosphate was pumped into the dilute chamber of the nanofiltration-electrodialysis unit, while a 0.5 M phosphate solution was simultaneously pumped into the concentrate chambers on both sides of the dilute chamber. Constant current operation was used, with a current of 20 mA / cm². 2 The flow rates of both the dilute and concentrate chambers were 0.6 L / min; after 2.5 h of treatment, the dilute solution was converted into a concentrate containing ADP.

[0054] The phosphate removal rate was 56.38%, and the ADP recovery rate was 82.56%.

[0055] Example 4

[0056] This embodiment provides a nanofiltration-electrodialysis coupling device, which includes three separation units. Each separation unit includes a first organic nanofiltration membrane assembly composed of two parallel organic nanofiltration membrane sheets and a second organic nanofiltration membrane assembly composed of two parallel organic nanofiltration membrane sheets. The membrane sheets are made of polyvinylidene fluoride with a molecular weight cutoff of 800-900. An anion exchange membrane and a cation exchange membrane are respectively disposed on the outer sides of the first organic nanofiltration membrane assembly and the second organic nanofiltration membrane assembly. The anion exchange membrane is a polyvinyl alcohol ion exchange membrane, and the cation exchange membrane is a perfluorosulfonic acid ion exchange membrane. The three separation units form a complete membrane stack.

[0057] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, as follows:

[0058] A mixed solution with an initial concentration of 1 mM ADP and 10 g / L sodium phosphate was pumped into the dilute chamber of the nanofiltration-electrodialysis unit, while a 0.3 M phosphate solution was simultaneously pumped into the concentrate chambers on both sides of the dilute chamber. Constant current operation was used, with a current of 15 mA / cm². 2 The flow rates of both the dilute and concentrate chambers were 0.5 L / min; after 3 hours of treatment, the dilute solution was converted into a concentrate containing ADP.

[0059] The phosphate removal rate was 68.59%, and the ADP recovery rate was 79.26%.

[0060] Example 5

[0061] This embodiment provides a nanofiltration-electrodialysis coupling device, which includes 5 separation units. Each separation unit includes 2 organic nanofiltration membranes made of polyamide and polyvinylidene fluoride, respectively, with a molecular weight cutoff of 900-1000. Each organic nanofiltration membrane has a pair of alternating anion and cation exchange membranes on both sides. The anion exchange membrane is a quaternized polyarylene ether sulfone ion exchange membrane, and the cation exchange membrane is a polyvinyl alcohol ion exchange membrane. The 5 separation units form a complete membrane stack.

[0062] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, as follows:

[0063] A mixed solution with an initial concentration of 1 mM ADP and 10 g / L sodium phosphate was pumped into the dilute chamber of the nanofiltration-electrodialysis unit, while a 0.5 M phosphate solution was simultaneously pumped into the concentrate chambers on both sides of the dilute chamber. Constant current operation was used, with a current of 20 mA / cm².2 The flow rates of both the dilute and concentrate chambers were 0.6 L / min; after 2.5 h of treatment, the dilute solution was converted into a concentrate containing ADP.

[0064] The phosphate removal rate was 79.33%, and the ADP recovery rate was 77.25%.

[0065] Example 6

[0066] This embodiment provides a nanofiltration-electrodialysis coupling device, which differs from the device in Embodiment 1 only in that the material of the organic nanofiltration membrane is replaced with cellulose acetate, while other conditions remain unchanged.

[0067] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, which is consistent with Embodiment 1.

[0068] The test results showed that the phosphate removal rate was 40.26% and the ADP recovery rate was 70.39%.

[0069] Example 7

[0070] This embodiment provides a nanofiltration-electrodialysis coupling device, which differs from the device in Embodiment 1 only in that the material of the organic nanofiltration membrane is replaced with polyacrylonitrile, while other conditions remain unchanged.

[0071] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, which is consistent with Embodiment 1.

[0072] The test results showed that the phosphate removal rate was 35.69% and the ADP recovery rate was 65.36%.

[0073] Example 8

[0074] This embodiment provides a nanofiltration-electrodialysis coupling device, which differs from the device in Embodiment 1 only in that the material of the organic nanofiltration membrane is replaced with sulfonated polysulfone, while other conditions remain unchanged.

[0075] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, which is consistent with Embodiment 1.

[0076] The test results showed that the phosphate removal rate was 38.26% and the ADP recovery rate was 75.23%.

[0077] Example 9

[0078] This embodiment provides a nanofiltration-electrodialysis coupling device, which differs from the device in Embodiment 1 only in that the cation exchange membrane is replaced with a perfluorocarboxylic acid ion exchange membrane, while other conditions remain unchanged.

[0079] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, which is consistent with Embodiment 1.

[0080] The phosphate removal rate was 33.18%, and the ADP recovery rate was 72.69%.

[0081] Example 10

[0082] This embodiment provides a nanofiltration-electrodialysis coupling device, which differs from the device in Embodiment 1 only in that the anion exchange membrane is replaced with a polybenzimidazole ion exchange membrane, while other conditions remain unchanged.

[0083] This embodiment also provides a method for separating ADP and phosphate using the nanofiltration-electrodialysis coupling device, which is consistent with Embodiment 1.

[0084] The phosphate removal rate was 38.91%, and the ADP recovery rate was 74.64%.

[0085] Comparative Example 1

[0086] This comparative example provides an electrodialysis device comprising four separation units, each of which includes a set of parallel-arranged anion exchange membranes and a cation exchange membrane, wherein the anion exchange membrane is a polyvinyl alcohol ion exchange membrane and the cation exchange membrane is a perfluorosulfonic acid ion exchange membrane, and the four separation units form a complete membrane stack.

[0087] This comparative example also provides a method for separating ADP and phosphate using the electrodialysis apparatus, as follows:

[0088] A mixed solution of 1 mM ADP and 10 g / L sodium phosphate was pumped into the dilute chamber of the electrodialysis device, while a 0.5 M phosphate solution was simultaneously pumped into the concentrate chamber. Constant pressure operation was used, with a voltage of 10 V and flow rates of 0.4 L / min in both the dilute and concentrate chambers. After 5 hours of treatment, a concentrated solution containing ADP was obtained in the dilute chamber.

[0089] The phosphate removal rate was 89.36%, and the ADP recovery rate was 15.33%.

[0090] In summary, compared with the electrodialysis device of Comparative Example 1, the nanofiltration-electrodialysis coupling device of the present invention can efficiently separate ADP from phosphate and recover ADP.

[0091] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0092] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0093] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A nanofiltration-electrodialysis coupling device for separating ADP and phosphate, characterized in that, The nanofiltration-electrodialysis coupling device is an electrodialyzer with an organic nanofiltration membrane inserted, comprising a membrane stack consisting of at least two separation units; each separation unit comprises a first ion exchange membrane assembly, a first organic nanofiltration membrane assembly, a second organic nanofiltration membrane assembly, and a second ion exchange membrane assembly arranged in parallel in sequence. The first organic nanofiltration membrane module and the second organic nanofiltration membrane module each independently contain 1-3 parallel-arranged organic nanofiltration membrane sheets; The first ion exchange membrane assembly and the second ion exchange membrane assembly are each independently selected from a single anion exchange membrane, a single cation exchange membrane, or an anion exchange membrane and a cation exchange membrane arranged alternately in parallel. The first ion exchange membrane assembly and the second ion exchange membrane assembly together constitute 1-3 pairs of anion and cation exchange membranes; The organic nanofiltration membranes are each independently selected from polyamide, polyethersulfone, or polyvinylidene fluoride. The molecular weight cutoff of each organic nanofiltration membrane is independently selected from 400 to 1000 Da; The anion exchange membranes are each independently selected from quaternized polyarylether sulfone ion exchange membranes and polyvinyl alcohol ion exchange membranes; The cation exchange membranes are each independently selected from perfluorosulfonic acid ion exchange membranes and polyvinyl alcohol ion exchange membranes.

2. The nanofiltration-electrodialysis coupling device according to claim 1, characterized in that, The number of separation units is 3-9.

3. The nanofiltration-electrodialysis coupling device according to claim 1, characterized in that, The number of separation units is 3-6.

4. A method for separating ADP and phosphate, characterized in that, The method is performed using the nanofiltration-electrodialysis coupling device as described in any one of claims 1-3, and specifically includes the following steps: A mixture containing ADP and phosphate is circulated into and out of the dilute chamber between the first organic nanofiltration membrane module and the second organic nanofiltration membrane module. A low-concentration phosphate solution is simultaneously circulated into and out of the concentrate chamber between the first ion exchange membrane module and the first organic nanofiltration membrane module, as well as the concentrate chamber between the second ion exchange membrane module and the second organic nanofiltration membrane module, for processing. After processing, ADP concentrate is output from the dilute chamber.

5. The method according to claim 4, characterized in that, The nanofiltration-electrodialysis coupling device operates in either constant current electrodialysis or constant voltage electrodialysis.

6. The method according to claim 4, characterized in that, The voltage of the nanofiltration-electrodialysis coupling device is set to 5-30 V.

7. The method according to claim 4, characterized in that, The voltage of the nanofiltration-electrodialysis coupling device is set to 10-20 V.

8. The method according to claim 4, characterized in that, The current of the nanofiltration-electrodialysis coupling device is set to 10-30 mA / cm². 2 .

9. The method according to claim 4, characterized in that, The current of the nanofiltration-electrodialysis coupling device is set to 10-20 mA / cm². 2 .

10. The method according to claim 4, characterized in that, The flow rate of the liquid in the dilute chamber is 0.2-0.6 L / min.

11. The method according to claim 4, characterized in that, The flow rate of the liquid in the dilute chamber is 0.4-0.6 L / min.

12. The method according to claim 4, characterized in that, The flow rate of the liquid in the concentration chamber is 0.2-0.6 L / min.

13. The method according to claim 4, characterized in that, The flow rate of the liquid in the concentration chamber is 0.4-0.6 L / min.

14. The method according to claim 4, characterized in that, The concentration of the low-concentration phosphate solution is 0.1-0.8M.

15. The application of the nanofiltration-electrodialysis coupling device according to any one of claims 1-3 or the method according to any one of claims 4-14 in the separation of charged compounds and salts.

16. The application of the nanofiltration-electrodialysis coupling device according to any one of claims 1-3 or the method according to any one of claims 4-14 in the recovery of ADP from a cell-free in vitro multi-enzyme catalytic conversion solution.

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