DEG-PTD ligand, preparation method and application thereof, and method for separating lanthanides and actinides from waste liquid

Abstract

The invention provides a DEG-PTD ligand, a preparation method and application thereof, and a method for separating lanthanides and actinides from waste liquid, and belongs to the technical field of extraction separation. Starting from the molecular structure design of the ligand, the novel DEG-PTD ligand is developed by designing the structure of the ligand, the ligand not only ensures the high distribution ratio of Eu, but also ensures the efficient reverse extraction of Am by introducing the water-soluble ligand, 99% of 241 Am loaded in the organic phase of the TODGA ligand can be reversely extracted into the water phase, the lanthanum actinide separation factor SFEu / Am of the DEG-PTD ligand is more than 200, and the stability of the DEG-PTD ligand is greatly improved. The separation effect is good. In addition, the ligand is good in water solubility and extraction kinetics, the water solubility is extremely good, and balance can be achieved within 5 min. The invention provides a new thought for deeply understanding lanthanum and actinide separation, and provides important support for sustainable development of nuclear energy and scientific treatment and safe management of existing radioactive wastes.

Description

Technical Field

[0001] The invention relates to the technical field of extraction and separation, in particular to a DEG-PTD ligand and a preparation method and application thereof, and a method for separating lanthanide elements and actinide elements from waste liquid. Background Art

[0002] The separation of lanthanides and actinides is very important in the safe management of nuclear waste and the sustainable development of nuclear energy. Due to the chemical complexity of these elements, the separation process is challenging.

[0003] Methods for separating lanthanides and actinides include physical methods and chemical methods. Physical methods include high-speed countercurrent chromatography (HSCCC) and methods based on graphene oxide ion sieving membranes, wherein: HCCCC is a new type of separation method that combines the advantages of liquid-liquid extraction and partition chromatography, does not require a solid carrier, and shows potential in the field of radiochemistry, and methods based on graphene oxide ion sieving membranes utilize the layered structure of graphene oxide nanosheets and adjustable nanoscale interlayer channels to achieve the separation of lanthanides and actinides. Chemical methods include ion exchange chromatography and liquid-liquid extraction, wherein ion exchange chromatography utilizes the different adsorption capacities of lanthanides and actinides on ion exchange resins for separation, and liquid-liquid extraction achieves separation by selecting appropriate extractants to transfer lanthanides and actinides from one solvent to another. The liquid-liquid extraction method in the related art has the problems of low separation factor and poor separation effect. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a DEG-PTD ligand and its preparation method and application, and a method for separating lanthanide and actinide from waste liquid. The separation factor SF of the DEG-PTD ligand for lanthanide and actinide of the present invention is Eu / Am High, good separation effect.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a DEG-PTD ligand having a structure shown in Formula I:

[0007]

[0008] The present invention also provides a method for preparing the DEG-PTD ligand described in the above technical solution, comprising the following steps:

[0009] Mixing 2,6-dibromopyridine, (trimethylsilyl)acetylene, CuI, Pd(PPh3)4 and a solvent to carry out a first substitution reaction to obtain 2,6-bis((trimethylsilyl)ethynyl)pyridine;

[0010] Mixing 2-(2-chloroethoxy)ethanol, sodium azide and water for a second substitution reaction to obtain 2-(2-azidoethoxy)ethanol;

[0011] The 2,6-bis((trimethylsilyl)ethynyl)pyridine, 2-(2-azidoethoxy)ethanol, K2CO3, CuSO4, sodium ascorbate, pyridine and solvent are mixed for click reaction to obtain the DEG-PTD ligand.

[0012] Preferably, the temperature of the first substitution reaction is 40-60° C. and the time is 15-20 h.

[0013] Preferably, the temperature of the second substitution reaction is 70-90° C. and the time is 12-20 hours.

[0014] Preferably, the click reaction is carried out in a protective atmosphere for 70 to 80 hours.

[0015] The present invention also provides the use of the DEG-PTD ligand described in the above technical solution in separating lanthanides and actinides.

[0016] The present invention also provides a method for separating lanthanides and actinides from waste liquid, comprising the following steps:

[0017] The waste liquid is mixed with an extractant for solvent extraction, wherein the extractant is the DEG-PTD ligand described in the above technical solution, and the waste liquid contains lanthanide elements and actinide elements.

[0018] Preferably, the lanthanide element includes europium, and the actinide element includes americium.

[0019] Preferably, the acidity of the waste liquid is 0.005-4M.

[0020] Preferably, the concentration of the DEG-PTD ligand in the system during the solvent extraction is 2.5-100 mM.

[0021] The present invention provides a DEG-PTD ligand having a structure shown in Formula I. Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention starts with the design of the ligand molecular structure. By designing the structure of the ligand, a new DEG-PTD ligand is developed. The ligand not only ensures a high distribution ratio for Eu, but also the introduction of the water-soluble ligand also ensures efficient stripping of Am. 99% of 241Am loaded in the organic phase of the TODGA ligand can be stripped into the aqueous phase. The lanthanum-actinium separation factor SF of the DEG-PTD ligand is Eu / AmAbove 200, the separation effect is good. In addition, the ligand has good water solubility and extraction kinetics, and the water solubility is excellent, and equilibrium can be reached in 5 minutes. The present invention provides a new idea for a deeper understanding of the separation of lanthanum and actinium, and provides important support for the sustainable development of nuclear energy, the scientific treatment of existing radioactive waste and safe management.

[0023] The present invention also provides a method for preparing the DEG-PTD ligand described in the above technical solution. The preparation method of the present invention has simple and efficient synthesis, low price, complies with the hydrogen bond organic framework CHON principle, and is easy for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a reaction schematic diagram of the preparation of DEG-PTD ligand in the embodiment;

[0025] Figure 2 is the acidity test curve of DEG-PTD;

[0026] Figure 3 is the ligand concentration extraction curve of DEG-PTD;

[0027] Figure 4 This is the kinetic test curve of DEG-PTD. DETAILED DESCRIPTION

[0028] The present invention provides a DEG-PTD ligand having a structure shown in Formula I:

[0029]

[0030] The present invention also provides a method for preparing the DEG-PTD ligand described in the above technical solution, comprising the following steps:

[0031] Mixing 2,6-dibromopyridine, (trimethylsilyl)acetylene, CuI, Pd(PPh3)4 and a solvent to carry out a first substitution reaction to obtain 2,6-bis((trimethylsilyl)ethynyl)pyridine;

[0032] Mixing 2-(2-chloroethoxy)ethanol, sodium azide and water for a second substitution reaction to obtain 2-(2-azidoethoxy)ethanol;

[0033] The 2,6-bis((trimethylsilyl)ethynyl)pyridine, 2-(2-azidoethoxy)ethanol, K2CO3, CuSO4, sodium ascorbate, pyridine and solvent are mixed for click reaction to obtain the DEG-PTD ligand.

[0034] In the present invention, unless otherwise specified, the raw materials used are all commercially available products in the art.

[0035] The present invention mixes 2,6-dibromopyridine, (trimethylsilyl)acetylene (ethynyl TMS), CuI, Pd(PPh3)4 and a solvent to carry out a first substitution reaction to obtain 2,6-bis((trimethylsilyl)ethynyl)pyridine.

[0036] In the present invention, the solvent is preferably a mixture of diisopropylamine (DIPA) and tetrahydrofuran (THF), and the volume ratio of diisopropylamine to tetrahydrofuran in the mixture is preferably 1:1.

[0037] In a specific embodiment of the present invention, the dried diisopropylamine and tetrahydrofuran are added into a Schlenk bottle and degassed using a "freeze-pump-thaw" method before use.

[0038] In the present invention, the molar ratio of 2,6-dibromopyridine to (trimethylsilyl)acetylene is preferably 21.11:84.427.

[0039] In the present invention, the molar ratio of 2,6-dibromopyridine to CuI is preferably 1:0.1.

[0040] In the present invention, the molar ratio of 2,6-dibromopyridine to Pd(PPh3)4 is preferably 1:0.05.

[0041] In the present invention, the usage ratio of the 2,6-dibromopyridine to the solvent is preferably 21.11 mmol:200-280 mL, more preferably 21.11 mmol:240 mL.

[0042] In the present invention, the temperature of the first substitution reaction is preferably 40-60°C, specifically 40, 45, 50, 55 or 60°C, and the time is preferably 15-20h, specifically 15, 16, 17, 18, 19 or 20h.

[0043] In a specific embodiment of the present invention, 2,6-dibromopyridine is added to a round-bottom flask, CuI is transferred to the flask, a syringe and a long needle are used to transfer the mixed solution from the Schlenk flask to the reaction flask, then, Pd(PPh3)4 is weighed into a sample bottle in a glove box, and then Pd(PPh3)4 is transferred to the round-bottom flask, and finally, ethynyl TMS is injected into the flask using a syringe and a long needle to carry out the first substitution reaction.

[0044] After the first substitution reaction is completed, the present invention stops the reaction and cools to room temperature, the obtained reaction mixture is filtered through a short diatomaceous earth column, the filtrate is evaporated through a rotary evaporator to obtain a primary product, the primary product is purified through a column, the product is collected, and evaporated through a rotary evaporator to obtain the 2,6-bis((trimethylsilyl)ethynyl)pyridine.

[0045] In the present invention, the length of the short diatomaceous earth chromatography column is preferably 5 to 10 cm.

[0046] In the present invention, the stationary phase used in the chromatographic column purification is silica, and the mobile phase is a mixture of dichloromethane (DCM) and polyethylene (PE), and the volume ratio of DCM to PE in the mixture is preferably 1:1.

[0047] The invention mixes 2-(2-chloroethoxy)ethanol, sodium azide and water to carry out a second substitution reaction to obtain 2-(2-azidoethoxy)ethanol.

[0048] In the present invention, the molar ratio of 2-(2-chloroethoxy)ethanol to sodium azide is preferably 46.416:116.04.

[0049] In the present invention, the usage ratio of 2-(2-chloroethoxy)ethanol to water is preferably 46.416 mmol:20-40 mL, and more preferably 46.416 mmol:30 mL.

[0050] In the present invention, the temperature of the second substitution reaction is preferably 70-90°C, specifically 70, 75, 80, 85 or 90°C, and the time is preferably 12-20h, specifically 12, 13, 14, 15, 16, 17, 18, 19 or 20h.

[0051] In a specific embodiment of the present invention, 2-(2-chloroethoxy)ethanol and sodium azide are added into a round-bottom flask, and then water is added, followed by heating to carry out the second substitution reaction.

[0052] After the second substitution reaction is completed, the present invention cools the reaction mixture naturally, adds a NaOH solution, extracts the aqueous phase with dichloromethane, and then dries the dichloromethane phase with anhydrous MgSO4, filters, and evaporates the solvent to obtain the 2-(2-azidoethoxy)ethanol.

[0053] In the present invention, the mass concentration of the NaOH solution is preferably 5%.

[0054] In the present invention, the usage ratio of the 2-(2-chloroethoxy)ethanol and the NaOH solution is preferably 46.416 mmol:80-120 mL, more preferably 46.416 mmol:100 mL.

[0055] In the present invention, the number of times of extracting the aqueous phase with dichloromethane is preferably 3 times.

[0056] After obtaining 2,6-bis((trimethylsilyl)ethynyl)pyridine and 2-(2-azidoethoxy)ethanol, the present invention mixes the 2,6-bis((trimethylsilyl)ethynyl)pyridine, 2-(2-azidoethoxy)ethanol, K2CO3, CuSO4, sodium ascorbate, pyridine and a solvent to perform a click reaction to obtain the DEG-PTD ligand.

[0057] In the present invention, the molar ratio of 2,6-bis((trimethylsilyl)ethynyl)pyridine to 2-(2-azidoethoxy)ethanol is preferably 9.22:23.61.

[0058] In the present invention, the molar ratio of 2,6-bis((trimethylsilyl)ethynyl)pyridine to K2CO3 is preferably 9.22:58.802.

[0059] In the present invention, the molar ratio of 2,6-bis((trimethylsilyl)ethynyl)pyridine to CuSO4 is preferably 9.22:7.01.

[0060] In the present invention, the molar ratio of 2,6-bis((trimethylsilyl)ethynyl)pyridine to pyridine is preferably 9.22:98.941.

[0061] In the present invention, the CuSO4 is preferably used in the form of CuSO4·5H2O.

[0062] In the present invention, the molar ratio of 2,6-bis((trimethylsilyl)ethynyl)pyridine to sodium ascorbate is preferably 9.22:14.108.

[0063] In the present invention, the solvent is preferably degassed dichloromethane and degassed water, and the usage ratio of the 2,6-bis((trimethylsilyl)ethynyl)pyridine, degassed dichloromethane and degassed water is preferably 9.22mmol:100-120mL:100-120mL, more preferably 9.22mmol:114mL:114mL.

[0064] In the present invention, the click reaction is preferably carried out in a protective atmosphere, preferably nitrogen, for 70 to 80 hours, specifically 70, 72, 75 or 80 hours, and at room temperature, i.e., no additional heating or cooling is required.

[0065] In a specific embodiment of the present invention, 2,6-bis((trimethylsilyl)ethynyl)pyridine (main ring), K2CO3, CuSO4·5H2O, 2-(2-azidoethoxy)ethanol (side chain), sodium ascorbate and a stirring bar were added to a Schlenk tube, and then degassed dichloromethane and degassed water were added. Subsequently, pyridine was added to the Schlenk tube, and the resulting reaction mixture was subjected to the click reaction at room temperature under a nitrogen atmosphere.

[0066] After the click reaction is completed, the present invention preferably evaporates the reaction mixture, dissolves ethylenediaminetetraacetic acid (EDTA) in H2O, adjusts the pH value to 7 with NaOH solution, then adds all the solution into a flask, stirs the mixture for 1 hour and then evaporates, then dissolves the product with methanol, adds silica into the flask for adsorption, and uses a methanol-dichloromethane mixture as a mobile phase for chromatography purification to obtain the DEG-PTD ligand.

[0067] In the present invention, the volume percentage of methanol in the methanol-dichloromethane mixture is preferably 10%.

[0068] The present invention also provides the use of the DEG-PTD ligand described in the above technical solution in separating lanthanides and actinides.

[0069] The present invention also provides a method for separating lanthanides and actinides from waste liquid, comprising the following steps:

[0070] The waste liquid is mixed with an extractant for solvent extraction, wherein the extractant is the DEG-PTD ligand described in the above technical solution, and the waste liquid contains lanthanide elements and actinide elements.

[0071] In the present invention, the waste liquid is preferably high-level waste liquid, which refers to waste liquid with a radioactivity greater than 3.7×10 10 The radioactive waste liquid of 100 Bq / L is preferably derived from the raffinate water phase of the co-decontamination circulation section of the spent fuel reprocessing plant, and the acidity of the high-level waste liquid is preferably 3-4M.

[0072] In the present invention, the lanthanide element includes europium (Eu), and the actinide element includes americium (Am).

[0073] In the present invention, the acidity of the waste liquid is preferably 0.005-4 M, specifically 0.005, 0.01, 0.05, 0.10, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 3 or 4 M. In the present invention, nitric acid is preferably used to adjust the acidity of the waste liquid.

[0074] In the present invention, the concentration of the DEG-PTD ligand in the system during the solvent extraction is 2.5-100 mM, specifically 2.5, 5, 10, 20, 25, 30, 40, 60, 80 or 100 mM.

[0075] In the present invention, the temperature of the solvent extraction is preferably room temperature, and the time is preferably 5 to 60 minutes, specifically 5, 10, 15, 30, 45 or 60 minutes.

[0076] In the present invention, the solvent extraction is preferably carried out under stirring conditions, and the stirring speed is preferably 3000 rpm.

[0077] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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.

[0078] Figure 1 This is a schematic diagram of the preparation of DEG-PTD ligands according to an embodiment of the present invention.

[0079] Example 1

[0080] 1.1 Main ring synthesis (a): 2,6-bis((trimethylsilyl)ethynyl)pyridine

[0081]

[0082] Dry THF and DIPA, add the dried THF and DIPA (volume ratio 1:1) into a Schlenk flask and degas using the "freeze-pump-thaw" method. Then, add 5g (21.11mmol) of 2,6-dibromopyridine to a 500mL round-bottom flask. Quantitatively transfer 402.4mg (2.11mmol, 10mol%) of CuI to the flask. Use a syringe and a long needle to transfer 240mL of the degassed DIPA / THF mixture from the Schlenk flask to the reaction flask. Then, weigh 1.207g (1.055mmol, 5mol%) of Pd(PPh3)4 into a sample bottle in a glove box, and then transfer PdPd(PPh3)4 to a round-bottom flask. Finally, use a syringe and a long needle to inject 11.935mL (84.427mmol) of ethynyl TMS into the flask. The reaction mixture was stirred and refluxed at 50°C for 16 hours. After 16 hours, the reaction was stopped and cooled to room temperature. The reaction mixture was filtered through a short diatomaceous earth column (10 cm), and the filtrate was evaporated on a rotary evaporator to obtain the initial product, which was purified by a chromatographic column (400 g silica, mobile phase: DCM: PE volume ratio = 1: 1). The product was collected and evaporated on a rotary evaporator to obtain 5.95 g (100%) of solid pure product.

[0083] 1 H NMR (400MHz, CDCl3) δ (ppm): 7.59-7.55 (m, 1H), 7.36-7.34 (m, 2H), 0.24-0.22 (m, 18H); 13C NMR (400MHz, CDCl3) δ (ppm): 143.45 (2C), 136.35 (1C), 126.78 (2C), 103.21 (2C), 95.53 (2C), 0.21 (6C); MS (ESI + )m / z calcd.for[M+H] + :272.13,found:272.1235;MS(ESI + )m / z calcd.for[2M+H] + :543.25,found:543.2414;MS(ESI + )m / z calcd.for[2M+Na] + :565.23,found:565.2228.

[0084] 1.2 Branched chain synthesis (b): 2-(2-azidoethoxy)ethanol

[0085]

[0086] 5 mL of 2-(2-chloroethoxy)ethanol (46.416 mmol) and 7.54 g of sodium azide (116.04 mmol) were added to a 100 mL round-bottom flask, and then 30 mL of pure water was added. The reaction was heated to 80°C. After 16 h of reaction, the reaction mixture was cooled, 100 mL of 5 wt% NaOH solution was added, the aqueous phase was extracted with dichloromethane (3×100 mL), and the dichloromethane phase was dried over anhydrous MgSO4, filtered, and the solvent was evaporated to obtain 6.06 g (99%) of pure product.

[0087] 1 H NMR (400MHz, D2O) δ (ppm): 3.77-3.74 (m, 4H), 3.70-3.67 (m, 2H), 3.56-3.52 (m, 2H); 13C NMR (400MHz, D2O) δ (ppm): 71.70 (1C), 69.19 (1C), 60.44 (1C), 50.29 (1C); MS (ESI + )m / z calcd.for[M+Na] + :154.06, found: 154.0567; FT-IR (KBr disc): νmax 3535(s), 2566(w), 2164(m), 1837(s), 1511(s), 1380(s), 1014(m), 507(w).

[0088] 1.3DEG-PTD ligand synthesis (c)

[0089]

[0090] In a Schlenk tube (250 mL), 2.5 g (9.22 mmol) of 2,6-bis((trimethylsilyl)ethynyl)pyridine (main ring), 8.127 g of K2CO3 (58.802 mmol), 1.750 g of CuSO4·5H2O (7.01 mmol), 3.094 g (23.61 mmol) of 2-(2-azidoethoxy)ethanol (side chain), 2.795 g (14.108 mmol) of sodium ascorbate and a stirring bar were added. Then, 100 mL of degassed dichloromethane and 100 mL of degassed water were added. Next, 8.01 mL (98.941 mmol) of pyridine were added to the Schlenk tube. The reaction mixture was stirred at room temperature for 76 h under a nitrogen atmosphere. After 76 h, the reaction mixture was evaporated. 5 g of EDTA was dissolved in H2O and the pH value was adjusted to 7 with NaOH solution. All the solutions were then added to the flask. The mixture was stirred for 1 hour and then evaporated. The product was dissolved in 100 mL of methanol and 50 g of silica was added to the flask for adsorption. 400 g of silica was used as the stationary phase and 10 vol% methanol in dichloromethane was used as the mobile phase. The product was purified by chromatography, Rf = 0.35. Finally, 2.44 g of pure and dry product was obtained, with a yield of 80%.

[0091] 1 H NMR (400MHz, CDCl3) δ (ppm): 8.43 (s, 2H), 7.98-7.96 (d, J = 7.8Hz, 2H), 7.78-7.74 ( m,1H),4.56-4.54(m,4H),3.85-3.83(m,4H),3.71-3.68(m,6H),3.55-3.53(m,4H).

[0092] 13 C NMR (400MHz, CDCl3) δ (ppm): 149.98 (2C), 148.10 (2C), 137.91 (1C), 123.93 (2C), 119.23 (2C), 72.69 (2C), 69.27 (2C), 61.51 (2C), 50.41 (2C).

[0093] MS(ESI+)m / z calcd.for[M+Na] + :412.17,found:412.1723;MS(ESI+)m / zcalcd.for[2M+Na] + :801.35,found:801.3514; HRMS(ESI+)m / z calcd.for[M+Na] + :412.17,found:412.1704.

[0094] 2. Solvent extraction test

[0095] 2.1 Stock solution

[0096] The organic phases for all solvent extraction experiments were prepared using the tracer loaded organic phase (TLOP)-protocol.

[0097] Prepare the ligand stock solution by dissolving 674.2 mg of ligand in 10 mL of pure water to give a concentration of 160 mM.

[0098] A stock solution of 241Am(NO3)3 containing 0.01M nitric acid.

[0099] 152 / 154Eu(NO3)3 stock solution containing 0.01M nitric acid.

[0100] HNO3 stock solutions are 0.1M, 1M and 4M.

[0101] The stock solution of NaNO3 is 4M.

[0102] 2.2 Tracer-loaded organic phase (TLOP) - Scheme

[0103] 1. Preparation of irradiated aqueous phase

[0104] Prepare 100 mL of 3M HNO3 into a clean conical flask and add 10 mL of 3M HNO3 to a polypropylene centrifuge tube. Add 20 μL of 241Am tracer and 20 μL of 152 / 154Eu to the centrifuge tube.

[0105] 2. Preparation of TODGA

[0106] 0.2M TODGA (N,N,N′,N′-tetraoctyl-3-oxoglutaramide) organic phase: 3.521 g TODGA was dissolved in 30 mL kerosene / n-octanol (95:5, v / v) solution.

[0107] 3. Load

[0108] 20 mL of organic phase was added to the centrifuge tube containing water and 20 μL of 241Am tracer and 20 μL of 152 / 154Eu phase, and the centrifuge tube was properly closed. The centrifuge tube was then mounted on an orbital shaker and vibrated for 60 min. Afterwards, it was centrifuged at 3000 rpm for 2 min, and the aqueous phase was carefully transferred to a radioactive waste bottle.

[0109] 4. Washing (removing HNO3 dissolved in the organic phase)

[0110] Add 10 mL of 0.5 M HNO3 to the centrifuge tube containing the organic phase of the tracer, close the centrifuge tube and shake for 15 min. Centrifuge at 3000 rpm for 2 min and carefully transfer the aqueous phase to a radioactive waste bottle.

[0111] Then, a sample of the organic phase was taken for LSC to measure the initial 241Am and 152 / 154Eu counts.

[0112] The prepared TLOP should be stored safely in a refrigerator to minimize solvent evaporation and maintain the same count ratio over many days. For each sample tube, use 1 mL of organic phase.

[0113] 2.3 Three types of tests:

[0114] 2.3.1 Acidity test to determine the effect of nitric acid concentration on distribution ratio and SF Eu / Am impact.

[0115] For the ligand DEG-PTD, acidity studies were performed at 0.005, 0.01, 0.05, 0.10, 0.15, 0.20, 0.30, 0.50, and 1.00 M nitric acid, and the standard concentration of the ligand was 80 mM, 0.5 M sodium nitrate.

[0116] 2.3.2 Kinetic studies to determine the kinetics of the extraction process.

[0117] The aqueous phase contained a constant concentration of ligand (80 mM) and 0.5 M nitric acid. The sodium nitrate concentration was 0.5 M and the test was performed at intervals of 5, 10, 15, 30, 45 and 60 min.

[0118] 2.3.3 Ligand concentration extraction studies to determine the effect of ligand concentration on partition ratio and SF Eu / Am impact.

[0119] The ligand DEG-PTD was tested at concentrations of 10, 20, 40, 60, 80 and 100 mM. The acidity was constant at 0.15 M nitric acid and the sodium nitrate concentration was 0.5 M. 2.3.4

[0121] Each 1 mL of aqueous phase and 1 mL of organic phase were mixed in a PP vial, shaken using a vortex oscillator (standard 60 min), and then centrifuged (3000 rpm, 2 min) to completely separate the two phases. Samples from the aqueous and organic phases were then collected, and the radioactivity in different channels was counted using LSC, which could distinguish the α radioactivity of 241Am and the β radioactivity of 152Eu / 154Eu. To ensure the accuracy of the data, each sample was measured for at least 5 min. The count ratios in the two phases were then interpreted as the extraction parameters D Am and D Eu, while SF Eu / Am Then calculate D Eu / D Am Compare.

[0122] 2.4 Solvent extraction results

[0123] Figure 2 is the acidity test curve of DEG-PTD, Figure 3 is the DEG-PTD ligand concentration extraction curve, Figure 4 The kinetic test curve of DEG-PTD shows that the best acidity of DEG-PTD is 0.05-0.2M, and the separation effect is good. Eu / Am The temperature is 200-240, and the equilibrium time is good, less than 5 minutes.

[0124] In summary, the present invention starts with the design of the ligand molecular structure, and develops a new DEG-PTD ligand by designing the structure of the ligand. The ligand not only ensures a high distribution ratio for Eu, but also the introduction of the water-soluble ligand also ensures efficient stripping of Am, and can strip 99% of 241Am loaded in the organic phase of the TODGA ligand into the aqueous phase. The lanthanum-actinium separation factor SF of the DEG-PTD ligand is Eu / Am Above 200, the separation effect is good. In addition, the ligand has good water solubility and extraction kinetics, and the water solubility is excellent, and equilibrium can be reached in 5 minutes. The present invention provides a new idea for a deeper understanding of the separation of lanthanum and actinium, and provides important support for the sustainable development of nuclear energy, the scientific treatment of existing radioactive waste and safe management.

[0125] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A DEG-PTD ligand, characterized in that: It has the structure shown in Formula I:

2. The method for preparing the DEG-PTD ligand according to claim 1, characterized in that: The following steps are involved: Mixing 2,6-dibromopyridine, (trimethylsilyl)acetylene, CuI, Pd(PPh3)4 and a solvent to carry out a first substitution reaction to obtain 2,6-bis((trimethylsilyl)ethynyl)pyridine; Mixing 2-(2-chloroethoxy)ethanol, sodium azide and water for a second substitution reaction to obtain 2-(2-azidoethoxy)ethanol; The 2,6-bis((trimethylsilyl)ethynyl)pyridine, 2-(2-azidoethoxy)ethanol, K2CO3, CuSO4, sodium ascorbate, pyridine and solvent are mixed for click reaction to obtain the DEG-PTD ligand.

3. The preparation method according to claim 2, characterized in that: The temperature of the first substitution reaction is 40-60° C. and the time is 15-20 hours.

4. The preparation method according to claim 2, characterized in that: The temperature of the second substitution reaction is 70-90° C. and the time is 12-20 hours.

5. The preparation method according to claim 2, characterized in that: The click reaction is carried out in a protective atmosphere for 70 to 80 hours.

6. Use of the DEG-PTD ligand according to claim 1 in separation of lanthanides and actinides.

7. A method for separating lanthanides and actinides from waste liquid, characterized in that: The following steps are involved: The waste liquid is mixed with an extractant for solvent extraction, wherein the extractant is the DEG-PTD ligand according to claim 1, and the waste liquid contains lanthanides and actinides.

8. The method according to claim 7, characterized in that The lanthanide elements include europium, and the actinide elements include americium.

9. The method according to claim 7, characterized in that: The acidity of the waste liquid is 0.005-4M.

10. The method according to claim 7, characterized in that The concentration of the DEG-PTD ligand in the system during the solvent extraction is 2.5-100 mM.

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