Preparation method, adsorption method and desorption method of lithium isotope adsorbent

Abstract

The invention discloses a preparation method, adsorption and desorption method of a lithium isotope adsorbent, and the preparation method comprises the following steps: dissolving a metal ion substrate and an organic ligand in a solvent according to a molar ratio of (1-10): (1-10), and heating the obtained mixed solution; and after the reaction is completed, cooling, centrifuging, washing and drying to obtain the lithium isotope adsorbent. According to the method, the efficient lithium ion adsorption effect can be achieved, enrichment of 7Li in the adsorbent is achieved through the selective adsorption difference of 7Li in the lithium salt solution, the abundance of 7Li is effectively improved, the separation factor is increased, and the excellent separation effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of lithium adsorption, and in particular to a preparation method, adsorption and desorption method of a lithium isotope adsorbent. Background Art

[0002] Lithium and its compounds are important strategic resources for national economy and national defense construction. Lithium in nature mainly exists in two stable isotopes: 6 Li and 7 Li exists in the form of 6 Li and 7 Li differs only by one neutron, so their physical and chemical properties are extremely similar, which makes the separation process extremely challenging, even increasing the abundance by 0.1% is extremely difficult. Deuterium (D) and tritium (T) combine to form helium ( 4 He) will release huge amounts of energy. This process not only does not produce long-lived radioactive fragments, but also releases far more energy than nuclear fission. Since the content of tritium in nature is very low, 6 Li is often used as a tritium breeder to produce nuclear fusion materials. It is estimated that 1kg 6 The total energy released by Li fission to produce tritium when used for fusion can generate at least 10,000 kilowatts of electricity, which is much greater than the energy released by the fission of the same mass of 235U. 6 The abundance of Li is only 7.53%. It is used as a tritium multiplier to realize DT nuclear fusion reaction. 6 The abundance of Li must be above 30%. 7 Li is widely used as a heat transfer medium and neutron moderator in reactors due to its small neutron absorption cross section. 7 LiOH is also used to adjust the pH value of the coolant in pressurized water reactors. Therefore, the separation of lithium isotopes is crucial to the development of my country's nuclear energy technology, national defense security and sustainable development strategy.

[0003] At present, the lithium amalgam method is the only method that can achieve industrial separation of lithium isotopes. However, due to the serious environmental and health risks caused by the use of a large amount of mercury in the production process, many European and American countries have stopped using this technology. Existing methods and technologies also have problems such as low lithium isotope separation factor, poor separation effect, and toxic extractants or separation materials used, which seriously hinder the progress of industrial separation of lithium isotopes. Therefore, it is particularly urgent to develop a green, non-toxic adsorption material that can efficiently adsorb and separate lithium isotopes. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing a lithium isotope adsorbent, and an adsorption and desorption method to solve the problems of low lithium isotope separation factor, poor separation effect, complex preparation process of adsorption materials and toxicity of adsorption materials in the existing process of separating lithium isotopes.

[0005] The present invention provides a method for preparing a lithium isotope adsorbent, comprising the following steps:

[0006] S1, dissolving the metal ion substrate and the organic ligand in a solvent 1 at a molar ratio of 1-10:1-10, and stirring until completely dissolved to obtain a mixed solution;

[0007] Wherein, the metal ion substrate is selected from one or more of Ni(NO3)2, Cd(NO3)2, Zn(NO3)2, Cr(NO3)3, Co(NO3)3, Fe(NO3)3, Al(NO3)3, Cd(OH)2, AlCl3, CuCl2, ZrCl4, and FeCl3;

[0008] The organic ligand is selected from one or more of 1,3,5-benzenetricarboxylic acid, terephthalic acid, 2,5-dimethylterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dichlorobenzoic acid, 2,5-dibromobenzoic acid, 2,5-bis(trifluoromethyl)terephthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,4-diazabicyclo[2.2.2]octane, 1,4-oxadiazine, 2,5-dihydroxyterephthalic acid, 4,4'-bipyridine, 4-pyridinecarboxylic acid, 2-methylimidazole, 1,3,5-tri(4-carboxyphenyl)benzene, 1,3,5-tri(pyridin-4-yl)benzene, 3,3'5,5'-tetracarboxyazobenzene, and 4,4'-dibromo-2,2'-bipyridine.

[0009] Wherein, the structural formula of the 1,3,5-benzenetricarboxylic acid is:

[0010] The structural formula of the terephthalic acid is:

[0011] The structural formula of the 2,5-dimethylterephthalic acid is:

[0012] The structural formula of the 2,5-diaminoterephthalic acid is: The structural formula of the 2,5-dichloro-p-dibenzoic acid is: The structural formula of the 2,5-dibromobenzoic acid is: The structural formula of the 2,5-bis(trifluoromethyl)terephthalic acid is: The structural formula of the 2,6-naphthalene dicarboxylic acid is: The structural formula of the 4,4'-biphenyldicarboxylic acid is: The structural formula of the 1,4-diazabicyclo[2.2.2]octane is: The structural formula of the 1,4-diazine is: The structural formula of the 2,5-dihydroxyterephthalic acid is: The structural formula of the 4,4'-bipyridine is: The structural formula of the 4-pyridinecarboxylic acid is: The structural formula of the 2-methylimidazole is: The structural formula of the 1,3,5-tris(4-carboxyphenyl)benzene is: The structural formula of the 1,3,5-tri(pyridin-4-yl)benzene is: The structural formula of the 3,3'5,5'-tetracarboxylazobenzene is:

[0013] The structural formula of the 4,4'-dibromo-2,2'-bipyridine is:

[0014] The solvent 1 in step S1 is selected from one or more of water, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, methanol, and ethanol; and the volume of the solvent 1 is 20 mL to 150 mL.

[0015] S2, heating the mixed solution in step S1;

[0016] Wherein, in step S2, the mixed solution is transferred to a reaction kettle for heating, and heated at 100° C. to 300° C. for 1 h to 72 h.

[0017] S3. After the reaction is completed, the mixture is cooled to room temperature, and then centrifuged, washed, and dried to obtain the lithium isotope adsorbent.

[0018] The present invention also provides a method for adsorbing and desorbing lithium isotopes, using the lithium isotope adsorbent described above, and the adsorption and desorption method comprises the following steps:

[0019] S10, dissolving lithium salt in solvent 2 to prepare a 0.1-5 mol / L lithium salt solution;

[0020] Wherein, the lithium salt in step S10 is selected from one or more of LiCl, LiBr, LiI, LiOH, LiNO3, LiClO4, LiSCN, CH3COOLi, CF3COOLi, CHF2COOLi, CH2FCOOLi or LiNTf2;

[0021] The solvent 2 in step S10 is selected from one or more of water, methanol, ethanol, acetonitrile, acetone, N,N-dimethylformamide, N,N-diethylformamide, and dimethyl sulfoxide.

[0022] S20, dispersing 0.1-1000 mg of lithium isotope adsorbent into 1-100 mL of lithium salt solution, adding a magnet, and stirring on a magnetic stirrer to obtain an adsorbed lithium isotope adsorbent;

[0023] Wherein, the stirring temperature in step S20 is 0-100° C., and the stirring time is 1 h-48 h.

[0024] S30, using an acidic solution to elute the adsorbed lithium isotope adsorbent obtained in step S20, so that the lithium isotope on the lithium isotope adsorbent is removed from the lithium isotope adsorbent;

[0025] The concentration of the acidic solution is 0.1 mol / L to 5 mol / L; the number of desorptions is 1 to 5 times, and each desorption lasts 1 hour to 24 hours.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1. The present invention develops a method for preparing a lithium isotope adsorbent, which can achieve efficient lithium ion adsorption by 7 The selective adsorption of Li is achieved by 7 The enrichment of Li in the adsorbent effectively improves 7 The abundance of Li increases the separation factor and achieves excellent separation effect.

[0028] 2. The metal ion substrate and organic ligand materials used in the present invention are low-cost, easy to obtain, and have a simple synthesis process, which is convenient for mass production, greatly reducing the preparation cost of the materials and improving the economy of the entire adsorption process.

[0029] 3. The system design of the present invention focuses on simplicity, making the preparation process simple and intuitive, and very convenient to operate, thereby significantly improving work efficiency and reducing the technical difficulty of operation.

[0030] 4. The materials used in the present invention all meet the green chemistry standards and are non-toxic and harmless, ensuring long-term feasibility in environmental protection and resource conservation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a flow chart of the preparation method of the lithium isotope adsorbent. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inside", "outside", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0034] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If the terms "first", "second", "third" are described, they are only used for the purpose of description and distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following is an explanation of the embodiments of the present invention based on its overall structure.

[0036] See also Figure 1 The preparation method of the lithium isotope adsorbent of the present invention comprises the following steps:

[0037] S1, dissolving the metal ion substrate and the organic ligand in a solvent 1 at a molar ratio of 1-10:1-10, and stirring until completely dissolved to obtain a mixed solution;

[0038] Wherein, the metal ion substrate is selected from one or more of Ni(NO3)2, Cd(NO3)2, Zn(NO3)2, Cr(NO3)3, Co(NO3)3, Fe(NO3)3, Al(NO3)3, Cd(OH)2, AlCl3, CuCl2, ZrCl4, and FeCl3;

[0039] The organic ligand is selected from one or more of 1,3,5-benzenetricarboxylic acid, terephthalic acid, 2,5-dimethylterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dichlorobenzoic acid, 2,5-dibromobenzoic acid, 2,5-bis(trifluoromethyl)terephthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,4-diazabicyclo[2.2.2]octane, 1,4-oxadiazine, 2,5-dihydroxyterephthalic acid, 4,4'-bipyridine, 4-pyridinecarboxylic acid, 2-methylimidazole, 1,3,5-tri(4-carboxyphenyl)benzene, 1,3,5-tri(pyridin-4-yl)benzene, 3,3'5,5'-tetracarboxyazobenzene, and 4,4'-dibromo-2,2'-bipyridine.

[0040] Wherein, the structural formula of the 1,3,5-benzenetricarboxylic acid is: The structural formula of the terephthalic acid is: The structural formula of the 2,5-dimethylterephthalic acid is: The structural formula of the 2,5-diaminoterephthalic acid is: The structural formula of the 2,5-dichloro-p-dibenzoic acid is: The structural formula of the 2,5-dibromobenzoic acid is: The structural formula of the 2,5-bis(trifluoromethyl)terephthalic acid is: The structural formula of the 2,6-naphthalene dicarboxylic acid is: The structural formula of the 4,4'-biphenyldicarboxylic acid is: The structural formula of the 1,4-diazabicyclo[2.2.2]octane is: The structural formula of the 1,4-diazine is: The structural formula of the 2,5-dihydroxyterephthalic acid is: The structural formula of the 4,4'-bipyridine is: The structural formula of the 4-pyridinecarboxylic acid is:

[0041] The structural formula of the 2-methylimidazole is:

[0042] The structural formula of the 1,3,5-tris(4-carboxyphenyl)benzene is:

[0043] The structural formula of the 1,3,5-tri(pyridin-4-yl)benzene is:

[0044] The structural formula of the 3,3'5,5'-tetracarboxylazobenzene is:

[0045] The structural formula of the 4,4'-dibromo-2,2'-bipyridine is:

[0046] The solvent 1 in step S1 is selected from one or more of water, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, methanol, and ethanol; and the volume of the solvent 1 is 20 mL to 150 mL.

[0047] S2, heating the mixed solution in step S1;

[0048] Wherein, in step S2, the mixed solution is transferred to a reaction kettle for heating, and heated at 100° C. to 300° C. for 1 h to 72 h.

[0049] S3. After the reaction is completed, the mixture is cooled to room temperature, and then centrifuged, washed, and dried to obtain the lithium isotope adsorbent.

[0050] The present invention also provides a method for adsorbing and desorbing lithium isotopes, using the lithium isotope adsorbent described above, and the adsorption and desorption method comprises the following steps:

[0051] S10, dissolving the lithium salt in solvent 2 to prepare a 0.1-5 mol / L lithium salt solution;

[0052] Wherein, the lithium salt in step S10 is selected from one or more of LiCl, LiBr, LiI, LiOH, LiNO3, LiClO4, LiSCN, CH3COOLi, CF3COOLi, CHF2COOLi, CH2FCOOLi or LiNTf2;

[0053] The solvent 2 in step S10 is selected from one or more of water, methanol, ethanol, acetonitrile, acetone, N,N-dimethylformamide, N,N-diethylformamide, and dimethyl sulfoxide.

[0054] S20, dispersing 0.1-1000 mg of lithium isotope adsorbent into 1-100 mL of lithium salt solution, adding a magnet, and stirring on a magnetic stirrer to obtain an adsorbed lithium isotope adsorbent;

[0055] Wherein, the stirring temperature in step S20 is 0-100° C., and the stirring time is 1 h-48 h.

[0056] S30, using an acidic solution to elute the adsorbed lithium isotope adsorbent obtained in step S20, so that the lithium isotope on the lithium isotope adsorbent is removed from the lithium isotope adsorbent;

[0057] The concentration of the acidic solution is 0.1 mol / L to 5 mol / L; the number of desorptions is 1 to 5 times, and each desorption lasts 1 hour to 24 hours.

[0058] The separation factor (α) of lithium isotopes can be expressed as:

[0059]

[0060] in, 7 Li s and 6 Li s Respectively represent the adsorbent 7 Li and 6 The proportion of Li, 7 Li l and 6 Li l Respectively represent the lithium salt solution phase 7 Li and 6 The proportion of Li.

[0061] Example 1

[0062] Preparation of lithium isotope adsorbent: In this embodiment, Fe(NO3)3 and organic ligand material 1,3,5-benzenetricarboxylic acid are dissolved in 100 mL of water at a molar ratio of 3:2, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 150°C for 10 hours. After the reaction is completed, the mixture is cooled to room temperature, and the adsorbent is centrifuged, washed with a solvent, and vacuum dried to obtain the lithium isotope adsorbent.

[0063] Lithium isotope adsorption and desorption: LiNO3 was dissolved in water to prepare a 0.3 mol / L lithium salt solution, 20 mg of lithium isotope adsorbent was dispersed into 5 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption time was 12 hours, and the lithium isotope adsorbent was obtained. 7 Li desorption solution. The isotope abundance of the desorption solution and the lithium salt solution after adsorption was tested by inductively coupled plasma mass spectrometry, and the separation factor was calculated to be 1.035.

[0064] Example 2

[0065] Preparation of lithium isotope adsorbent: In this embodiment, FeCl3 and organic ligand material terephthalic acid are dissolved in 100 mL of water at a molar ratio of 1:1, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 170°C for 24 hours. After the reaction is completed, the mixture is cooled to room temperature, and the adsorbent is centrifuged, washed with a solvent, and vacuum dried to obtain the lithium isotope adsorbent.

[0066] Lithium isotope adsorption and desorption: LiNO3 was dissolved in water to prepare a 0.3 mol / L lithium salt solution, 20 mg of lithium isotope adsorbent was dispersed into 5 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption time was 12 hours, and the lithium isotope adsorbent was obtained. 7 Li desorption solution. The isotope abundance of the desorption solution and the lithium salt solution after adsorption was tested by inductively coupled plasma mass spectrometry, and the separation factor was calculated to be 1.033.

[0067] Example 3

[0068] Preparation of lithium isotope adsorbent: In this embodiment, Fe(NO3)3 and organic ligand material 1,3,5-benzenetricarboxylic acid are dissolved in 100 mL of water at a molar ratio of 3:2, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 150°C for 10 hours. After the reaction is completed, the adsorbent is cooled to room temperature, centrifuged, washed with solvent, and vacuum dried to obtain the lithium isotope adsorbent;

[0069] Lithium isotope adsorption and desorption: LiNO3 was dissolved in methanol to prepare a 0.3 mol / L lithium salt solution for use, 20 mg of lithium isotope adsorbent was dispersed into 5 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption time was 12 hours, and the lithium isotope adsorbent was obtained. 7 Li desorption solution. The isotope abundance of the desorption solution and the lithium salt solution after adsorption was tested by inductively coupled plasma mass spectrometry, and the separation factor was calculated to be 1.037.

[0070] Example 4

[0071] Preparation of lithium isotope adsorbent: In this embodiment, FeCl3 and organic ligand material 2,5-diaminoterephthalic acid are dissolved in 100 mL of water at a molar ratio of 1:1, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 170°C for 24 hours. After the reaction is completed, the adsorbent is cooled to room temperature, centrifuged, washed with solvent, and vacuum dried to obtain the lithium isotope adsorbent;

[0072] Lithium isotope adsorption and desorption: LiNO3 was dissolved in water to prepare a 0.3 mol / L lithium salt solution, 20 mg of lithium isotope adsorbent was dispersed into 5 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption time was 12 hours, and the lithium isotope adsorbent was obtained. 7 Li desorption solution. The isotope abundance of the desorption solution and the lithium salt solution after adsorption was tested by inductively coupled plasma mass spectrometry, and the separation factor was calculated to be 1.031.

[0073] Example 5

[0074] Preparation of lithium isotope adsorbent: In this embodiment, Al(NO3)3 and organic ligand material 1,3,5-benzenetricarboxylic acid are dissolved in 300 mL of water at a molar ratio of 3:2, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 160°C for 15 hours. After the reaction is completed, the adsorbent is cooled to room temperature, centrifuged, washed with solvent, and vacuum dried to obtain the lithium isotope adsorbent;

[0075] Lithium isotope adsorption and desorption: LiNO3 was dissolved in water to prepare a 0.3 mol / L lithium salt solution, 20 mg of lithium isotope adsorbent was dispersed into 5 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption lasting 24 hours, to obtain 7 Li desorption solution. The isotope abundance of the desorption solution and the lithium salt solution after adsorption was tested by inductively coupled plasma mass spectrometry, and the separation factor was calculated to be 1.038.

[0076] Implementation Case 6

[0077] Preparation of lithium isotope adsorbent: In this embodiment, Fe(NO3)3 and organic ligand material 1,3,5-benzenetricarboxylic acid are dissolved in 100 mL of water at a molar ratio of 3:2, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 150°C for 10 hours. After the reaction is completed, the adsorbent is cooled to room temperature, centrifuged, washed with solvent, and vacuum dried to obtain the lithium isotope adsorbent;

[0078] Lithium isotope adsorption and desorption: LiBr was dissolved in water to prepare a 0.3 mol / L lithium salt solution, 20 mg of lithium isotope adsorbent was dispersed into 5 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption lasting 12 hours, to obtain 7 Li desorption solution. The isotope abundance of the desorption solution and the lithium salt solution after adsorption was tested by inductively coupled plasma mass spectrometry, and the separation factor was calculated to be 1.034.

[0079] Example 7

[0080] Preparation of lithium isotope adsorbent: In this embodiment, Fe(NO3)3 and organic ligand material 1,3,5-benzenetricarboxylic acid are dissolved in 100 mL of water at a molar ratio of 3:2, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 150°C for 10 hours. After the reaction is completed, the adsorbent is cooled to room temperature, centrifuged, washed with solvent, and vacuum dried to obtain the lithium isotope adsorbent;

[0081] Lithium isotope adsorption and desorption: LiNO3 was dissolved in water to prepare a 0.2 mol / L lithium salt solution, 20 mg of lithium isotope adsorbent was dispersed into 5 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption lasting 12 hours, to obtain 7 Li desorption solution. The desorption solution and the lithium salt solution after adsorption were tested for isotope abundance using an inductively coupled plasma mass spectrometer, and the calculated separation factor was 1.036.

[0082] Example 8

[0083] In this embodiment, Fe(NO3)3 and the organic ligand material 1,3,5-benzenetricarboxylic acid are dissolved in 100 mL of water at a molar ratio of 3:2, and after being evenly dissolved, they are placed in a reaction kettle and heated in an oven at 150°C for 10 hours. After the reaction is completed, the adsorbent is cooled to room temperature, centrifuged, washed with solvent, and vacuum dried to obtain the lithium isotope adsorbent;

[0084] Lithium isotope adsorption and desorption: LiNO3 was dissolved in water to prepare a 0.3 mol / L lithium salt solution, 30 mg of lithium isotope adsorbent was dispersed into 3 mL of the prepared lithium salt solution, and a magnet was added, and stirred on a magnetic stirrer at 25 °C for 24 hours; the lithium isotope adsorbent was separated by centrifugation, and the lithium ions adhering to its surface were washed off, and the lithium isotope-rich adsorbent was desorbed 5 times with 0.5 mol / L hydrochloric acid, each desorption time was 12 hours, and the lithium isotope adsorbent was obtained. 7 Li desorption solution. The isotope abundance of the desorption solution and the lithium salt solution after adsorption was tested by inductively coupled plasma mass spectrometry, and the separation factor was calculated to be 1.033.

[0085] In summary, the present invention provides a method for preparing a lithium isotope adsorbent, which uses a metal ion substrate and an organic ligand to prepare a lithium isotope adsorbent, and 7 The selective adsorption of Li is achieved by 7 The enrichment of Li in the adsorbent effectively improves 7 The abundance of Li can be increased, the separation factor can be improved, and an excellent separation effect can be achieved; the material is low-cost, easy to obtain, and the synthesis process is simple, which is convenient for mass production, greatly reducing the preparation cost of the material and improving the economy of the entire adsorption process; the system design of the present invention focuses on simplicity, making the preparation process simple and intuitive, and the operation is very convenient, thereby significantly improving work efficiency and reducing the technical difficulty of operation; the materials used in the present invention all meet the green chemistry standards, are non-toxic and harmless, and ensure the long-term feasibility in environmental protection and resource conservation.

[0086] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for preparing a lithium isotope adsorbent, characterized in that: The preparation method comprises the following steps: S1, dissolving the metal ion substrate and the organic ligand in a solvent 1 at a molar ratio of 1-10:1-10 to obtain a mixed solution; S2, heating the mixed solution in step S1; S3, after the reaction is completed, cooling to room temperature, centrifuging, washing, and drying to obtain the lithium isotope adsorbent; Wherein, the metal ion substrate is selected from one or more of Ni(NO3)2, Cd(NO3)2, Zn(NO3)2, Cr(NO3)3, Co(NO3)3, Fe(NO3)3, Al(NO3)3, Cd(OH)2, AlCl3, CuCl2, ZrCl4, and FeCl3; The organic ligand is selected from one or more of 1,3,5-benzenetricarboxylic acid, terephthalic acid, 2,5-dimethylterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dichlorobenzoic acid, 2,5-dibromobenzoic acid, 2,5-bis(trifluoromethyl)terephthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,4-diazabicyclo[2.2.2]octane, 1,4-oxadiazine, 2,5-dihydroxyterephthalic acid, 4,4'-bipyridine, 4-pyridinecarboxylic acid, 2-methylimidazole, 1,3,5-tri(4-carboxyphenyl)benzene, 1,3,5-tri(pyridin-4-yl)benzene, 3,3'5,5'-tetracarboxyazobenzene, and 4,4'-dibromo-2,2'-bipyridine.

2. The method for preparing a lithium isotope adsorbent according to claim 1, characterized in that: In the step S2, the mixed solution is transferred to a reaction kettle for heating, and heated at 100° C. to 300° C. for 1 h to 72 h.

3. The method for preparing a lithium isotope adsorbent according to claim 1, characterized in that: The solvent 1 in step S1 is selected from one or more of water, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, methanol, and ethanol.

4. The method for preparing a lithium isotope adsorbent according to claim 1, characterized in that: The volume of the solvent 1 in step S1 is 20 mL to 150 mL.

5. A method for adsorption and desorption of lithium isotopes, characterized in that: The lithium isotope adsorbent is prepared by the preparation method according to any one of claims 1 to 4, wherein the adsorption and desorption method comprises the following steps: S10, dissolving the lithium salt in solvent 2 to prepare a 0.1-5 mol / L lithium salt solution; S20, dispersing 0.1-1000 mg of lithium isotope adsorbent into 1-100 mL of lithium salt solution, adding a magnet, and stirring on a magnetic stirrer to obtain an adsorbed lithium isotope adsorbent; S30, using an acidic solution to elute the adsorbed lithium isotope adsorbent obtained in step S20, so that the lithium isotopes on the lithium isotope adsorbent are removed from the lithium isotope adsorbent.

6. The method for adsorption and desorption of lithium isotopes according to claim 5, characterized in that: The lithium salt in step S10 is selected from one or more of LiCl, LiBr, LiI, LiOH, LiNO3, LiClO4, LiSCN, CH3COOLi, CF3COOLi, CHF2COOLi, CH2FCOOLi or LiNTf2.

7. The method for adsorption and desorption of lithium isotopes according to claim 5, characterized in that: The solvent 2 in step S10 is selected from one or more of water, methanol, ethanol, acetonitrile, acetone, N,N-dimethylformamide, N,N-diethylformamide, and dimethyl sulfoxide.

8. The method for adsorption and desorption of lithium isotopes according to claim 5, characterized in that: The stirring temperature in step S20 is 0 to 100° C., and the stirring time is 1 to 48 hours.

9. The method for adsorption and desorption of lithium isotopes according to claim 5, characterized in that: The concentration of the acidic solution is 0.1 mol / L to 5 mol / L.

10. The method for adsorption and desorption of lithium isotopes according to claim 5, characterized in that: The desorption times are 1 to 5 times, and each desorption time is 1 to 24 hours.

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