Membrane chromatography method and device for separating boron isotope

Abstract

The invention provides a method and a device for separating boron isotopes through membrane chromatography. The invention provides a method for separating boron isotopes by membrane chromatography, which comprises the following steps: by taking a composite membrane material as a stationary phase and a boron-containing solution as a mobile phase, directly enabling the boron-containing solution to flow through a composite membrane to enrich 10B in a membrane phase and enrich 11B in a liquid phase, wherein the composite membrane contains a compound capable of separating boron isotope functional groups. The invention provides a membrane chromatography technology which has the advantages of a membrane technology and a chromatography technology, on one hand, through structural modification and functionalization of membrane ligand pore channels and surfaces, selective adsorption separation of the membrane on different target objects can be achieved, separation factors are increased, and the abundant membrane pore channel structure can effectively reduce internal diffusion resistance and improve separation efficiency; on the other hand, by constructing a multi-stage membrane chromatographic separation system, chromatographic column separation factors can be effectively increased, the separation time can be shortened, and the cost can be reduced.

Description

Technical Field

[0001] This invention relates to the field of isotope separation technology, and more specifically, to a membrane chromatography method and apparatus for separating boron isotopes. Background Technology

[0002] B-10 isotopes possess superior thermal neutron absorption properties, with an absorption cross-section as high as 3837 targets, four times that of natural boron. They play a crucial role in important fields such as clean nuclear energy, defense technology, high-end electronics, and cancer treatment. B-10 isotopes have a strong thermal neutron absorption cross-section, making them ideal materials for radiation shielding and intensity control in nuclear reactions, and thus a vital strategic material in the nuclear industry. Compared to natural boron, high-abundance (>80%) B-10 compounds can significantly improve the safe and controllable operation of nuclear fission reactors, extend the lifespan of nuclear power plants, and reduce the large-scale discharge and recovery of boron nuclear waste. In the nuclear industry, the use of high-abundance B-10 isotopes can also reduce the load on nuclear-powered military equipment and improve combat performance. The demand for B-10 isotopes continues to grow at a rate of approximately 8.0% annually.

[0003] However, due to limitations in separation technology, China's production of high-abundance B-10 isotopes has fallen short of demand, leading to a long-term reliance on imports to meet domestic needs. Therefore, developing new technologies for the efficient separation and enrichment of boron isotopes is of great significance to the development of China's nuclear industry.

[0004] In existing technologies, the mainstream techniques for boron isotope separation include BF3 chemical exchange distillation, BF3 cryogenic distillation, solvent extraction, ion exchange chromatography, and laser spectroscopy. Among these, BF3 chemical exchange distillation is the only mature industrial-scale technology for separating boron isotopes internationally. However, due to the highly corrosive nature of BF3 and its extreme sensitivity to water, this method suffers from drawbacks such as high equipment investment, high energy consumption, and high protection requirements. Ion exchange chromatography, using boric acid aqueous solution as the mobile phase and boron-specific resin as the stationary phase, offers advantages such as high efficiency, energy saving, safety, and environmental friendliness. It has significant development potential in future high-efficiency and green separation technologies for boron isotopes. However, it suffers from problems such as low separation factor, slow mass transfer efficiency, and low separation efficiency, which have become key challenges for industrial applications. Chinese invention patent CN110143600A discloses a method for separating and purifying boron-10 and boron-11. The method involves loading a boron-specific resin (one or a combination of at least two of Amberlite IRA743, ZXC700, XSC800, D564, or Diaion CRB02 resin) onto a simulated moving bed of a chromatographic separation system to adsorb the feed onto the column. Simultaneously, a strong acid aqueous solution is pumped into the column to gradient-elute the boron-specific resin. The concentration of the strong acid aqueous solution increases by 0.03-0.5 mol / L per hour, and the flow rate increases by 0.01-0.5 BV / h per hour. After the simulated moving bed system reaches equilibrium, the enriched isotopes are collected at the extraction port of the simulated moving bed. 10 B is a concentrated boric acid solution; wherein the simulated bed is set into zones I to IV; zone II consists of 15 to 20 columns, zones I and III each consist of 2 columns, and zone IV consists of 0 to 2 columns. Zones I and III each consist of 2 ZXC700 resin columns. ZXC700 boron selective chelating resin is a macroporous chelating resin with N-methylglucosamine groups, crosslinked with styrene and divinylbenzene. This chemical structure forms complex anions with boron in the functional groups, and its amine moiety acts as an anion exchange group to capture the generated complex anions, thereby selectively adsorbing boron ions. This method is based on long-distance chromatographic columns, and the functional groups that can complex with boron are encapsulated in the crosslinked network structure, which greatly reduces the complexation performance of functional groups with boron and also increases the isotopic content. 10 The difficulty in eluting boron isotopes does not solve the problems of slow mass transfer efficiency and low separation efficiency in existing boron isotope separation technologies, and cannot meet the current requirements for high abundance boron isotope separation. 10 B. Production requirements.

[0005] Based on the current development of existing boron isotope separation technology, this invention provides a membrane chromatography technique that combines the advantages of membrane technology and chromatography technology, greatly shortening the time for boron isotope separation. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the present invention provides a method and apparatus for separating boron isotopes by membrane chromatography.

[0007] To achieve the above objectives, the present invention provides the following technical solutions.

[0008] As one aspect of the invention, this invention provides a method for separating boron isotopes by membrane chromatography, using a composite membrane material as the stationary phase and a boron-containing solution as the mobile phase, wherein the boron-containing solution is directly flowed through the composite membrane. 10 B is enriched in the membrane phase. 11 B is enriched in the liquid phase; wherein, the composite membrane contains compounds with separable boron isotope functional groups. The boron isotopes in the boron-containing solution are of natural abundance (…). 10 B 19.8%, 11 B 20.2%.

[0009] Preferably, the mass fraction of the compound with separable boron isotope functional groups is 3% to 16%.

[0010] In a preferred embodiment, the flow rate of the boron-containing solution through the composite membrane is 0.2 to 6 mL / min.

[0011] Preferably, the flow rate of the naturally abundant boron-containing solution through the composite membrane is 0.5 to 2.5 mL / min.

[0012] In a preferred embodiment, the boron concentration of the boron-containing solution is 0.5-3.5 g / L.

[0013] Preferably, the boron concentration of the boron-containing solution is 0.8-2.6 g / L.

[0014] In a preferred embodiment, the pH of the boron-containing solution is 1-7.

[0015] Preferably, the pH of the boron-containing solution is 2.5-5.

[0016] In a preferred embodiment, the compound with separable boron isotope functional groups is selected from any one of polyethyleneimine, N-methyl-D-glucosamine, and dopamine hydrochloride.

[0017] In a preferred embodiment, the method for preparing the composite membrane includes mixing the compound with separable boron isotope functional groups, the membrane-forming polymer, and additives, stirring to react, obtaining a homogeneous solution, allowing it to stand to remove bubbles, casting it into a membrane, immersing it in a coagulation bath, and then performing post-treatment to obtain the composite membrane material.

[0018] In a preferred embodiment, the mass ratio of the membrane-forming polymer to the compound with separable boron isotope functional groups is 0.3 to 3.5, preferably 1.0 to 2.0.

[0019] In some specific embodiments, the casting process includes pouring the solution onto a film-forming plate, scraping it into a film, exposing it to air for a period of time to obtain a scraped film, and then immersing it in the coagulation bath.

[0020] In some specific embodiments, the exposure time is 1s to 40s; preferably, the exposure time is 5s to 15s.

[0021] In some specific embodiments, the coagulation bath is deionized water.

[0022] In some specific embodiments, the coagulation bath temperature is 15°C to 35°C, and preferably, the coagulation bath temperature is 20°C to 30°C.

[0023] In some specific embodiments, the soaking time in the coagulation bath is 2 to 10 days, preferably 3 to 7 days.

[0024] In some specific embodiments, the post-treatment includes immersing the membrane material in deionized water to remove water-soluble substances from the membrane, with the deionized water being changed multiple times during the immersion process.

[0025] In a preferred embodiment, the film-forming polymer is polyvinyl chloride or polyvinylidene fluoride.

[0026] Preferably, the additive is polyethylene glycol.

[0027] Preferably, the degree of polymerization of polyethylene glycol is 400-2000.

[0028] More preferably, the degree of polymerization of polyethylene glycol is 400-1000.

[0029] Preferably, the mass fraction of polyethylene glycol is 3%-8%.

[0030] As a preferred embodiment, the method for separating boron isotopes by membrane chromatography specifically includes the following steps:

[0031] S1. Using a boron-containing solution with natural abundance as the mobile phase, the boron-containing solution is flowed through the composite membrane, and the flow rate of the mobile phase is controlled.

[0032] S2. Dynamically monitor the boron concentration in the effluent. When the ratio of the boron concentration in the effluent to the boron concentration in the initial feed liquid is 0.995 to 1.0, the adsorption stage is complete.

[0033] S3. After eluting the composite membrane with an eluent, the product containing... 10B's washing solution;

[0034] S4. When the ratio of boron concentration in the washing solution to boron concentration in the initial feed solution is ≤0.01, the elution stage is completed.

[0035] In a preferred embodiment, the eluent is a hydrochloric acid solution.

[0036] Preferably, the concentration of the hydrochloric acid solution is 0.05–1 mol / L; more preferably, it is 0.1–0.5 mol / L.

[0037] In a preferred embodiment, the composite membrane further includes a regeneration stage; after the elution stage is completed, the composite membrane is washed with water until neutral, then immersed in the regeneration solution, or the regeneration solution is passed through the composite membrane.

[0038] Preferably, the regenerated solution is a sodium hydroxide solution.

[0039] Preferably, the concentration of the sodium hydroxide solution is 0.5–2 mol / L; more preferably, it is 0.5–1.0 mol / L.

[0040] As one of the objectives of the invention, the present invention also provides an apparatus for membrane chromatography for separating boron isotopes, comprising at least a composite membrane and a membrane support for fixing the composite membrane.

[0041] Preferably, the method for preparing the composite membrane includes mixing the compound with separable boron isotope functional groups, the membrane-forming polymer, and additives, stirring to react, obtaining a homogeneous solution, allowing it to stand to remove bubbles, casting it into a membrane, immersing it in a coagulation bath, and then performing post-treatment to obtain the composite membrane material; the composite membrane material is then cut and fixed inside the membrane support.

[0042] Membrane chromatography, used for the separation of boron isotopes, combines membrane separation technology with chromatographic separation principles to achieve the separation of boron isotopes. 10 B (natural abundance approximately 19.8%) and 11 Separation of B (natural abundance approximately 80.2%). This technology combines the selective permeation properties of membrane materials with the adsorption-desorption enrichment properties of chromatography, thus replacing traditional high-energy-consuming separation methods such as chemical exchange and distillation, especially in the nuclear industry. 10 B-neutron absorbing materials, high purity in semiconductor manufacturing 11 It has significant application value in fields such as B.

[0043] Furthermore, the core of the membrane chromatography separation of boron isotopes in this invention lies in the membrane material's... 10 B's high selectivity, thus 10 B is enriched in the membrane phase and can [enrich B]. 10 B was enriched from a natural abundance of 19.8% to approximately ~21%, achieving10 The initial enrichment and separation of B is characterized by high efficiency and low energy consumption.

[0044] The composite membrane material provided by this invention modifies the boron isotope separation functional groups to obtain a composite membrane material with boron isotope separation effect. When this membrane material is applied to a boric acid aqueous solution of boron products from a salt lake for boron isotope separation, the ortho- or meta-hydroxyl groups in the membrane material undergo esterification with boron acid to generate boron-oxygen tetracoordinate (BO) compounds. (4) The polycyclic chelate of boron acid solution undergoes boron adsorption and boron isotope exchange reactions. 10 B tends to use BO (4) Form coordination enrichment occurs in the membrane phase. 11 B tends to use BO (3) The boron isotopes are enriched in boric acid solution through formal coordination, thereby achieving separation of boron isotopes. The protonation of the amine matrix can neutralize the hydrogen ions generated in the reaction, which is beneficial to the reaction and thus improves the separation performance of the material.

[0045] The beneficial effects of the technical solution provided by this invention compared with the prior art are as follows:

[0046] This invention provides a membrane chromatography technique that combines the advantages of both membrane and chromatography techniques. On the one hand, by modifying and functionalizing the membrane ligand pores and surface, selective adsorption and separation of different target analytes can be achieved, increasing the separation factor. The rich membrane pore structure can effectively reduce internal diffusion resistance and improve separation efficiency. On the other hand, by constructing a multi-stage membrane chromatography separation system, the column separation factor can be effectively improved, separation time shortened, and costs reduced. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0048] This invention discloses a method for separating boron isotopes by constructing a membrane chromatography separation system. The process steps are as follows: several composite membranes are selected and tightly stacked in a membrane support, the membrane support is tightened, and a membrane module is assembled as the stationary phase for membrane chromatography separation. A boric acid solution of a certain concentration is used as the mobile phase. A peristaltic pump is used to control the flow rate, and the sample is injected from bottom to top. Adsorption-desorption-washing-regeneration operations are performed. The effluent is continuously sampled at a certain volume, and its boron concentration and boron abundance are determined.

[0049] Specifically, in the above separation process, the thickness of the composite membrane prepared is 0.1-0.2 mm.

[0050] In some specific embodiments, 1-20 composite films are stacked together, and more preferably, 3-10 composite films are stacked together.

[0051] In some specific embodiments, the concentration of boron in the mobile phase is 0.5-3.5 g / L, preferably 0.8-2.6 g / L.

[0052] In some specific embodiments, the pH of the mobile phase solution is 1-7, preferably 2.5-5.

[0053] In some specific embodiments, the concentration of hydrochloric acid in the eluent is 0.05-1 mol / L, preferably 0.1-0.5 mol / L.

[0054] In some specific embodiments, the peristaltic pump feed flow rate is 0.2-6 mL / min, preferably 0.5-2.5 mL / min.

[0055] In some specific embodiments, the volume of the effluent sampled each time is 2-20 mL, preferably 2-10 mL.

[0056] In some specific embodiments, the concentration of sodium hydroxide in the regenerated solution is 0.5-2 mol / L, preferably 0.5-1.0 mol / L.

[0057] The technical solution of this invention includes four stages: adsorption, desorption, washing, and regeneration. During the adsorption process, when the ratio of the boron concentration in the effluent to the boron concentration in the initial feed liquid is 0.995-1.0, adsorption is stopped, and the next desorption experiment is carried out. During the desorption process, when the ratio of the boron concentration in the effluent to the boron concentration in the initial feed liquid is ≤0.01, the next washing and regeneration operations are carried out.

[0058] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0059] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0060] Example 1

[0061] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0062] (1) Preparation of membrane materials, the specific steps of which include:

[0063] N,N-dimethylacetamide and N-methyl-D-glucosamine were weighed and dissolved by stirring at 80°C to obtain a 16% N-methyl-D-glucosamine solution. Polyvinyl chloride (PVC) and polyethylene glycol 400 were then added and stirred until homogeneous. The mass ratio of PVC to N-methyl-D-glucosamine was 1.2, and the mass fraction of polyethylene glycol 400 was 7%. Stirring was continued for 20 hours to obtain a homogeneous solution, which was then allowed to stand to remove bubbles. The homogeneous solution was then cast onto a clean glass plate, and a 0.15cm thick membrane was formed by scraping the casting solution with a scraper. After exposure for 15 seconds, the membrane was immersed in a coagulation bath (deionized water) at 20°C. After the membrane separated from the glass plate, it was soaked in deionized water for 3 days, with the deionized water continuously replaced to remove water-soluble substances from the membrane, resulting in a composite membrane material with adsorption and separation functions. This material was then stored in deionized water.

[0064] (2) Assembly of membrane chromatography apparatus

[0065] The composite membrane material is cut into circular pieces with a diameter of 5 cm. Three membrane pieces with a thickness of 0.15 cm are selected and stacked tightly in a membrane support with a sandwich structure consisting of a porous filter disc for feeding liquid and a membrane stack. The membrane support is tightened to fix the composite membrane and the membrane module is assembled as a stationary phase for membrane chromatography.

[0066] (3) Separation of boron isotopes

[0067] A boric acid solution with a boron concentration of 1.58 g / L and natural abundance was used as the mobile phase. The solution pH was 2.5. The flow rate was controlled at 1.0 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 10 mL each time, and its boron concentration was determined.

[0068] When the ratio of boron concentration in the effluent to that in the initial feed solution is 0.995 (the criterion for completion of separation), desorption is performed using 0.1 mol / L HCl solution at an injection rate of 1.0 mL / min. Each sample of the desorbed solution is 5 mL. The boron concentration and abundance in the desorbed solution are measured, and the desorbed solution is calculated. 10 The boron abundance can be enriched up to 20.60% (natural abundance, the same below). When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0069] Example 2

[0070] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0071] (1) The preparation steps of the membrane material are the same as those in Example 1.

[0072] (2) Assembly of membrane chromatography apparatus

[0073] The composite membrane stored in deionized water was cut into circular pieces with a diameter of 5 cm. Ten membrane pieces with a thickness of 0.15 cm were selected and tightly stacked in a membrane support with a sandwich structure consisting of a porous filter disc for feed liquid and membrane stack. The membrane support was tightened to assemble a membrane module as a stationary phase for membrane chromatography.

[0074] (3) Separation of boron isotopes

[0075] A boric acid solution with a boron concentration of 1.05 g / L and natural abundance was used as the mobile phase. The solution pH was 2.5. The flow rate was controlled at 1.0 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 10 mL each time, and its boron concentration was determined.

[0076] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.998, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 0.5 mL / min. The volume of desorbed solution sampled each time was 3.5 mL, and the boron concentration and boron abundance in the desorbed solution were measured.

[0077] Calculation of the desorption solution 10 The boron abundance can be enriched up to 21.00%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0078] Example 3

[0079] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0080] (1) The preparation steps of the membrane material are the same as those in Example 1, except that the thickness of the coated membrane is 0.15 cm.

[0081] (2) Assembly of membrane chromatography apparatus

[0082] The composite membrane stored in deionized water was cut into circular pieces with a diameter of 4 cm. Eight membrane pieces with a thickness of 0.10 cm were selected and tightly stacked in a membrane support with a sandwich structure consisting of a porous filter disc for feed liquid and membrane stack. The membrane support was tightened to assemble a membrane module, which serves as the stationary phase for membrane chromatography.

[0083] (3) Separation of boron isotopes

[0084] A boric acid solution with a boron concentration of 2.58 g / L and natural abundance was used as the mobile phase. The solution pH was 4. The flow rate was controlled at 1.5 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 8 mL each time, and its boron concentration was determined.

[0085] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.997, desorption was performed using 0.2 mol / L HCl solution at an injection rate of 1.0 mL / min. The volume of desorbed solution sampled each time was 8 mL, and the boron concentration and boron abundance in the desorbed solution were measured.

[0086] Calculation of the desorption solution 10 The boron abundance can be enriched up to 20.40%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 1.0 mol / L NaOH solution is used for regeneration.

[0087] Example 4

[0088] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0089] (1) The preparation steps of the membrane material are the same as those in Example 1, except that the thickness of the coated membrane is 0.2 cm.

[0090] (2) Assembly of membrane chromatography apparatus

[0091] The composite membrane stored in deionized water was cut into circular pieces with a diameter of 4 cm. Four membrane pieces with a thickness of 0.20 cm were selected and stacked tightly in the membrane support. The membrane support was tightened to assemble the membrane module as a membrane chromatography stationary phase.

[0092] (3) Separation of boron isotopes

[0093] A boric acid solution with a boron concentration of 1.04 g / L and natural abundance was used as the mobile phase. The solution pH was 5. The flow rate was controlled at 1.0 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 12 mL each time, and its boron concentration was determined.

[0094] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.996, desorption was performed using 0.5 mol / L HCl solution at an injection rate of 0.5 mL / min. The volume of desorbed solution sampled each time was 8 mL, and the boron concentration and boron abundance in the desorbed solution were measured.

[0095] Calculation of the desorption solution 10The boron abundance can be enriched up to 19.90%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 1.0 mol / L NaOH solution is used for regeneration.

[0096] Example 5

[0097] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0098] (1) The preparation steps of the membrane material are the same as those in Example 1, except that the thickness of the coated membrane is 0.10 cm.

[0099] (2) Assembly of membrane chromatography apparatus

[0100] The composite membrane stored in deionized water was cut into circular pieces with a diameter of 4 cm. Ten membrane pieces with a thickness of 0.10 cm were selected and tightly stacked in a membrane support with a sandwich structure consisting of a porous filter disc for feed liquid and membrane stack. The membrane support was tightened to assemble a membrane module as a stationary phase for membrane chromatography.

[0101] (3) Separation of boron isotopes

[0102] A boron isotope adsorption separation was performed using a boron isotope solution with a boron concentration of 1.22 g / L and a pH of 3.5, injected from bottom to top at a flow rate of 2.0 mL / min using a peristaltic pump. 10 B is enriched in the membrane phase. 11 B is enriched in the effluent. The volume of the effluent sample is 10 mL each time, and the boron concentration in the effluent is measured.

[0103] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.996, the composite membrane material was desorbed using a 0.5 mol / L HCl solution at a sampling rate of 1.5 mL / min. The volume of the desorbed solution was 2 mL each time, and the boron concentration and boron abundance in the desorbed solution were measured.

[0104] Calculation of the desorption solution 10 The boron abundance can be enriched up to 20.30%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0105] Example 6

[0106] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0107] (1) The preparation steps of the membrane material are the same as those in Example 1, except that the thickness of the coated membrane is 0.15 cm.

[0108] (2) Assembly of membrane chromatography apparatus

[0109] The composite membrane stored in deionized water was cut into circular pieces with a diameter of 4 cm. Six membrane pieces with a thickness of 0.15 cm were selected and tightly stacked in a membrane support with a sandwich structure consisting of a porous filter disc for feed liquid and membrane stack. The membrane support was tightened to assemble a membrane module as a stationary phase for membrane chromatography.

[0110] (3) Separation of boron isotopes

[0111] A boric acid solution with a boron concentration of 1.57 g / L and natural abundance was used as the mobile phase. The solution pH was 4. The flow rate was controlled at 2.0 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 15 mL each time, and its boron concentration was determined.

[0112] When the ratio of boron concentration in the effluent to that in the initial feed solution was 0.999, desorption was performed using 0.3 mol / L HCl solution at an injection rate of 2.0 mL / min. The volume of desorbed solution sampled each time was 2 mL, and the boron concentration and boron abundance in the desorbed solution were measured.

[0113] Calculation of the desorption solution 10 The boron abundance can be enriched up to 20.15%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.3 mol / L NaOH solution is used for regeneration.

[0114] Example 7

[0115] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0116] (1) The preparation steps of the membrane material are the same as those in Example 1, except that the thickness of the coated membrane is 0.15 cm.

[0117] (2) Assembly of membrane chromatography apparatus

[0118] The composite membrane stored in deionized water was cut into circular pieces with a diameter of 5 cm. Five membrane pieces with a thickness of 0.15 cm were selected and tightly stacked in a membrane support with a sandwich structure consisting of a porous filter disc for feed liquid and a membrane stack. The membrane support was tightened to assemble a membrane module, which serves as the stationary phase for membrane chromatography.

[0119] (3) Separation of boron isotopes

[0120] A boric acid solution with a boron concentration of 0.87 g / L and natural abundance was used as the mobile phase. The solution pH was 3. The flow rate was controlled at 0.5 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 10 mL each time, and its boron concentration was determined.

[0121] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.999, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 2.5 mL / min. The volume of desorbed solution sampled each time was 2 mL, and the boron concentration and boron abundance in the desorbed solution were measured.

[0122] Calculation of the desorption solution 10 The boron abundance can be enriched up to 20.57%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.3 mol / L NaOH solution is used for regeneration.

[0123] Example 8

[0124] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0125] (1) The preparation steps of the membrane material are the same as those in Example 1, except that the thickness of the coated membrane is 0.15 cm.

[0126] (2) Assembly of membrane chromatography apparatus

[0127] The composite membrane stored in deionized water was cut into circular pieces with a diameter of 4 cm. Six membrane pieces with a thickness of 0.15 cm were selected and tightly stacked in a membrane support with a sandwich structure consisting of a porous filter disc for feed liquid and membrane stack. The membrane support was tightened to assemble a membrane module as a stationary phase for membrane chromatography.

[0128] (3) Separation of boron isotopes

[0129] A boric acid solution with a boron concentration of 1.20 g / L and natural abundance was used as the mobile phase. The solution pH was 4.5. The flow rate was controlled at 1.5 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 20 mL each time, and its boron concentration was determined.

[0130] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.999, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 1.0 mL / min. The volume of desorbed solution sampled each time was 3 mL, and the boron concentration and boron abundance in the desorbed solution were measured.

[0131] Calculation of the desorption solution 10The boron abundance can be enriched up to 20.61%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0132] Example 9

[0133] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0134] (1) The preparation steps of the membrane material are the same as those in Example 1.

[0135] (2) Assembly of membrane chromatography apparatus

[0136] The composite membrane material is cut into circular pieces with a diameter of 5 cm. Select membrane sheets with a thickness of 0.15 cm and stack them tightly in a membrane support with a sandwich structure consisting of a porous filter disc for feeding liquid and membrane stack. Tighten the membrane support to assemble a membrane module as a stationary phase for membrane chromatography.

[0137] (3) Separation of boron isotopes

[0138] A boric acid solution with a boron concentration of 1.58 g / L and natural abundance was used as the mobile phase. The solution pH was 2.5. The flow rate was controlled at 1.0 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 10 mL each time, and its boron concentration was determined.

[0139] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.995, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 1.0 mL / min. Each sample of the desorbed solution was 5 mL. The boron concentration and abundance in the desorbed solution were measured, and the desorbed solution was calculated. 10 The boron abundance can be enriched up to 20.60%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0140] Example 9

[0141] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0142] (1) The preparation steps of the membrane material are the same as those in Example 1.

[0143] (2) Assembly of membrane chromatography apparatus

[0144] The composite membrane material is cut into circular pieces with a diameter of 5 cm. Select membrane sheets with a thickness of 0.15 cm and stack them tightly in a membrane support with a sandwich structure consisting of a porous filter disc for feeding liquid and membrane stack. Tighten the membrane support to assemble a membrane module as a stationary phase for membrane chromatography.

[0145] (3) Separation of boron isotopes

[0146] A boric acid solution with a boron concentration of 1.58 g / L and natural abundance was used as the mobile phase. The solution pH was 2.5. The flow rate was controlled at 1.0 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 10 mL each time, and its boron concentration was determined.

[0147] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.995, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 1.0 mL / min. Each sample of the desorbed solution was 5 mL. The boron concentration and abundance in the desorbed solution were measured, and the desorbed solution was calculated. 10 The boron abundance can be enriched up to 19.88%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0148] Example 10

[0149] This embodiment constructs a membrane chromatography separation system that combines membrane separation technology with chromatography technology for the separation of boron isotopes. Specific steps include:

[0150] (1) The preparation steps of the membrane material are the same as those in Example 1.

[0151] (2) Assembly of membrane chromatography apparatus

[0152] The composite membrane material is cut into circular pieces with a diameter of 5 cm. Ten membrane pieces with a thickness of 0.15 cm are selected and tightly stacked in a membrane support with a sandwich structure consisting of a porous filter disc for feeding liquid and a membrane stack. The membrane support is tightened to assemble a membrane module, which serves as the stationary phase for membrane chromatography.

[0153] (3) Separation of boron isotopes

[0154] A boric acid solution with a boron concentration of 1.58 g / L and natural abundance was used as the mobile phase. The solution pH was 2.5. The flow rate was controlled at 1.0 mL / min using a peristaltic pump. The sample was injected from bottom to top for boron isotope adsorption separation. The volume of the effluent was 10 mL each time, and its boron concentration was determined.

[0155] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.995, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 1.0 mL / min. Each sample of the desorbed solution was 5 mL. The boron concentration and abundance in the desorbed solution were measured, and the boron content in the desorbed solution was calculated. 10 The boron abundance can be enriched up to 21.01%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0156] Comparative Example 1

[0157] This embodiment constructs a membrane chromatography separation system for boron isotope separation. The specific steps are basically the same as those in Example 1, except that the thickness of the membrane scraped in step (1) is 0.45 cm, and then the resulting composite membrane is fixed in a membrane support.

[0158] The other steps are the same as in Example 1.

[0159] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.995, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 1.0 mL / min. Each sample of the desorbed solution was 5 mL. The boron concentration and abundance in the desorbed solution were measured, and the boron content in the desorbed solution was calculated. 10 The boron abundance can be enriched up to 19.91%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0160] Comparative Example 2

[0161] This embodiment constructs a membrane chromatography separation system for boron isotope separation. The specific steps are basically the same as in Example 1, except that the boron concentration of the boric acid solution in the mobile phase is 4 g / L.

[0162] The other steps are the same as in Example 1.

[0163] When the ratio of boron concentration in the effluent to the initial boron concentration in the feed solution was 0.995, desorption was performed using 0.1 mol / L HCl solution at an injection rate of 1.0 mL / min. Each sample of the desorbed solution was 5 mL. The boron concentration and abundance in the desorbed solution were measured, and the boron content in the desorbed solution was calculated. 10 The boron abundance can be enriched up to 20.23%. When the ratio of boron concentration in the desorption solution to boron concentration in the initial feed solution is 0.01, after washing with water until neutral, a 0.5 mol / L NaOH solution is used for regeneration.

[0164] The above are merely preferred embodiments of the present invention and do not limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these embodiments within the spirit and principles of the present invention, achieved through conventional substitutions or by achieving the same function without departing from the principles and spirit of the present invention, fall within the scope of protection of the present invention.

Claims

1. A method for separating boron isotopes by membrane chromatography, characterized in that, include: Using a composite membrane material as the stationary phase and a naturally abundant boron-containing solution as the mobile phase, the boron-containing solution is directly flowed through the composite membrane, so that... 10 B is enriched in the membrane phase. 11 B is enriched in the liquid phase; The composite membrane contains a compound that can separate boron isotope functional groups; The mass fraction of the compound with separable boron isotope functional groups is 3% to 16%.

2. The method for separating boron isotopes by membrane chromatography according to claim 1, characterized in that, The flow rate of the naturally abundant boron-containing solution through the composite membrane is 0.2–6 mL / min; preferably 0.5–2.5 mL / min.

3. The membrane chromatography method for separating boron isotopes according to claim 1, characterized in that, The boron concentration of the naturally abundant boron-containing solution is 0.5-3.5 g / L; preferably 0.8-2.6 g / L. The pH of the naturally abundant boron-containing solution is 1 to 7, preferably 2.5 to 5.

4. The method for separating boron isotopes by membrane chromatography according to claim 1, characterized in that, The thickness of the composite film is 0.1 to 0.2 mm; preferably, 1 to 20 composite films are used in combination; more preferably, 3 to 10 films are used in combination.

5. The method for separating boron isotopes by membrane chromatography according to claim 4, characterized in that, The method for preparing the composite membrane includes mixing the compound with separable boron isotope functional groups, the membrane-forming polymer, and additives, stirring to react, obtaining a homogeneous solution, allowing it to stand to remove bubbles, casting it into a membrane, immersing it in a coagulation bath, and then performing post-treatment to obtain the composite membrane material.

6. The method for separating boron isotopes by membrane chromatography according to claim 5, characterized in that, The compound with separable boron isotope functional groups is selected from any one of polyethyleneimine, N-methyl-D-glucosamine, and dopamine hydrochloride. The film-forming polymer is polyvinyl chloride or polyvinylidene fluoride; And / or, the additive is polyethylene glycol; And / or, the degree of polymerization of polyethylene glycol is 400-1000; And / or, the mass fraction of polyethylene glycol is 3%-8%.

7. The method for separating boron isotopes by membrane chromatography according to any one of claims 1-6, characterized in that, The specific steps include: S1. Using a boron-containing solution with natural abundance as the mobile phase, the boron-containing solution is flowed through the composite membrane, and the flow rate of the mobile phase is controlled. S2. Dynamically monitor the boron concentration in the effluent. When the ratio of the boron concentration in the effluent to the boron concentration in the initial feed liquid is 0.995 to 1.0, the adsorption stage is complete. S3. After eluting the composite membrane with an eluent, the product containing... 10 B's washing solution; S4. When the ratio of boron concentration in the washing solution to boron concentration in the initial feed solution is ≤0.01, the elution stage is completed.

8. The method for separating boron isotopes by membrane chromatography according to claim 7, characterized in that, The eluent is a hydrochloric acid solution; And / or, the concentration of the hydrochloric acid solution is 0.05–1 mol / L; preferably 0.1–0.5 mol / L.

9. The method for separating boron isotopes by membrane chromatography according to claim 7, characterized in that, The composite membrane further includes a regeneration stage; after the elution stage is completed, the composite membrane is washed with water until neutral, then immersed in the regeneration solution, or the regeneration solution is passed through the composite membrane. And / or, the regenerated solution is a sodium hydroxide solution; And / or, the concentration of the sodium hydroxide solution is 0.5–2 mol / L; preferably 0.5–1.0 mol / L.

10. An apparatus for membrane chromatography for separating boron isotopes, comprising at least a composite membrane and a membrane support for fixing the composite membrane; The method for preparing the composite membrane includes mixing the compound with separable boron isotope functional groups, the membrane-forming polymer, and additives, stirring to react, obtaining a homogeneous solution, allowing it to stand to remove bubbles, casting it into a membrane, immersing it in a coagulation bath, and then performing post-treatment to obtain the composite membrane material. The composite membrane material is cut and then fixed inside the membrane support.