A DAPhen ligand, a preparation method and application thereof, and a method for separating lanthanide and actinide elements from waste liquid

Abstract

The application provides a DAPhen ligand and a preparation method and application thereof, and a method for separating lanthanide elements and actinide elements from waste liquid, and belongs to the technical field of extraction separation. The application starts from the design of a ligand molecular structure, develops a new DAPhen ligand by designing the structure of the ligand, and ensures high distribution ratio of Eu, and meanwhile, the introduction of the water-soluble ligand also ensures efficient stripping of Am, and the lanthanide-actinide separation factor SF of four DAPhen ligands is up to 320, and the separation effect is good. Eu / Am In addition, the water-soluble ligand and the extraction kinetics are good, and balance can be reached in 10 minutes. The application provides a new idea for in-depth understanding of lanthanide-actinide separation, and provides technical support for establishing an advanced spent nuclear fuel reprocessing system and efficiently utilizing secondary actinide elements.

Description

Technical Field

[0001] This invention relates to the field of extraction and separation technology, and in particular to a DAPhen ligand, its preparation method and application, and a method for separating lanthanides and actinides from waste liquid. Background Technology

[0002] Currently, nuclear energy is a crucial solution to energy problems, especially for regions lacking energy resources. However, while nuclear energy makes significant contributions to humanity, it also generates large amounts of radioactive waste, posing direct or potential harm to human development and the environment. Therefore, the proper handling and disposal of radioactive waste has become a critical issue for all countries and a key factor affecting the sustainable development of nuclear energy. The safe handling and disposal of High Level Radioactive Liquid Waste (HLLW) is crucial to the overall management of radioactive waste.

[0003] Solvent extraction is the most commonly used separation method for extracting and separating rare earth elements, and for separating and recovering lanthanides and actinides in the nuclear industry. Solvent extraction utilizes the different solubilities of complexes of different lanthanide and actinide ions in organic and aqueous phases, resulting in different partition coefficients, to extract various rare earth ions. This method has gradually replaced the traditional fractional crystallization method and ion exchange method.

[0004] The solvent extraction method for separating lanthanides and actinides suffers from low separation factor and poor separation effect. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a DAPhen ligand, its preparation method and application, and a method for separating lanthanides and actinides from waste liquid. The separation factor SF of the DAPhen ligand of the present invention for lanthanum and actinides is... Eu / Am High efficiency and good separation effect.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a DAPhen ligand having the structure shown in Formula I:

[0008]

[0009] In Equation I, R1 and R2 are independent. In R1 and R2, “~~” indicates a connection point.

[0010] Preferably, the DAPhen ligand has a structure shown in any of formulas L-1 to L-4:

[0011]

[0012] This invention also provides a method for preparing the DAPhen ligand described in the above technical solution, comprising the following steps:

[0013] 2,9-dicarboxylic acid-1,10-o-phenanthroline, an organic solvent, and an acidic substance were mixed and refluxed to give dimethyl 2,9-dicarboxylic acid-1,10-o-phenanthroline.

[0014] The dimethyl 2,9-dicarboxy-1,10-o-phenanthroline, the substituted raw material, and the organic solvent were mixed and subjected to a substitution reaction to obtain the DAPhen ligand; the substituted raw material included one or more of 3-amino-1-propanol, 3-amino-1,2-propanediol, 2-(2-aminoethoxy)ethanol, and 2-(2-(2-aminoethoxy)ethoxy)ethanol.

[0015] Preferably, the reflux reaction is carried out at a temperature of 60–100°C for 6–12 hours.

[0016] Preferably, the substitution reaction is carried out at a temperature of 60–80°C for a time of 6–12 hours.

[0017] This invention also provides the application of the DAPhen ligand described in the above technical solution in the separation of lanthanides and actinides.

[0018] This invention also provides a method for separating lanthanides and actinides from waste liquid, comprising the following steps:

[0019] The waste liquid is mixed with an extractant for solvent extraction, wherein the extractant is the DAPhen ligand described in the above technical solution, and the waste liquid contains lanthanide and actinide elements.

[0020] Preferably, the lanthanide elements include europium, and the actinide elements include americium.

[0021] Preferably, the acidity of the waste liquid is 0.01 to 1.5 M.

[0022] Preferably, the concentration of DAPhen ligand in the system during solvent extraction is 2.5–40 mM.

[0023] This invention provides a DAPhen ligand having the structure shown in Formula I. Compared with the prior art, the advantages of this invention are as follows:

[0024] This invention starts with the design of ligand molecular structures. By designing the structure of the ligands, a new DAPhen ligand was developed. This ligand ensures a high partition ratio for Eu, while the introduction of this water-soluble ligand also guarantees efficient back-extraction of Am. The lanthanum-actinium separation factor (SF) of the DAPhen ligand is [not specified].Eu / Am The extraction temperature reached 320°C, resulting in excellent separation. Furthermore, the ligand exhibited good water solubility and extraction kinetics, reaching equilibrium within 10 minutes. This invention provides new insights into lanthanum-actinium separation and offers technical support for establishing advanced spent nuclear fuel reprocessing systems and efficiently utilizing minor actinides.

[0025] The present invention also provides a method for preparing the DAPhen ligand described in the above technical solution. The preparation method of the present invention is simple and easy to industrialize. Attached Figure Description

[0026] Figure 1 The reaction principle diagrams for preparing DAPhen ligands of formulas L-1 to L-4 are shown in the examples.

[0027] Figure 2 The acidity test curve for HP-DAPhen;

[0028] Figure 3 Extraction curves for ligand concentrations of HP-DAPhen;

[0029] Figure 4 The kinetic test curves for HP-DAPhen;

[0030] Figure 5 Acidity test curve for DHP-DAPhen;

[0031] Figure 6 Extraction curves for ligand concentrations of DHP-DAPhen;

[0032] Figure 7 The kinetic test curves for DHP-DAPhen are shown.

[0033] Figure 8 The acidity test curve for AE-DAPhen;

[0034] Figure 9 Extraction curves for ligand concentrations of AE-DAPhen;

[0035] Figure 10 The dynamic test curves for AE-DAPhen;

[0036] Figure 11 Acidity test curve for AEE-DAPhen;

[0037] Figure 12 Extraction curves for ligand concentrations of AEE-DAPhen;

[0038] Figure 13 The kinetic test curves for AEE-DAPhen are shown. Detailed Implementation

[0039] This invention provides a DAPhen ligand having the structure shown in Formula I:

[0040]

[0041] In Equation I, R1 and R2 are independent. In R1 and R2, “~~” indicates a connection point.

[0042] In this invention, the DAPhen ligand preferably has a structure shown in any of formulas L-1 to L-4:

[0043]

[0044] This invention also provides a method for preparing the DAPhen ligand described in the above technical solution, comprising the following steps:

[0045] 2,9-dicarboxylic acid-1,10-o-phenanthroline, an organic solvent, and an acidic substance were mixed and refluxed to give dimethyl 2,9-dicarboxylic acid-1,10-o-phenanthroline.

[0046] The dimethyl 2,9-dicarboxy-1,10-o-phenanthroline, the substituted raw material, and the organic solvent were mixed and subjected to a substitution reaction to obtain the DAPhen ligand; the substituted raw material included one or more of 3-amino-1-propanol, 3-amino-1,2-propanediol, 2-(2-aminoethoxy)ethanol, and 2-(2-(2-aminoethoxy)ethoxy)ethanol.

[0047] Unless otherwise specified, all raw materials used in this invention are commercially available products in the field.

[0048] In this invention, 2,9-dicarboxylic acid-1,10-o-phenanthroline, an organic solvent, and an acidic substance are mixed and refluxed to obtain dimethyl 2,9-dicarboxylic acid-1,10-o-phenanthroline.

[0049] In this invention, the organic solvent is preferably methanol (MeOH).

[0050] In this invention, the preferred ratio of 2,9-dicarboxylic acid-1,10-o-phenanthroline to organic solvent is 18.64 mmol: 15 mL.

[0051] In this invention, the acidic substance is preferably concentrated sulfuric acid, and the mass percentage of the concentrated sulfuric acid is preferably 95% to 98%.

[0052] In this invention, the preferred ratio of 2,9-dicarboxylic acid-1,10-o-phenanthroline to concentrated sulfuric acid is 18.64 mmol: 2 mL.

[0053] In this invention, the temperature of the reflux reaction is 60-100°C, specifically 60, 70, 80, 90 or 100°C, and the time is preferably 6-12 hours, specifically 6, 7, 8, 9, 10, 11 or 12 hours.

[0054] In a specific embodiment of the present invention, the 2,9-dicarboxylic acid-1,10-o-phenanthroline and methanol were added to a round-bottom flask, a magnetic stir bar was added, and then concentrated sulfuric acid was added dropwise to the reaction mixture. The resulting reaction mixture was heated to carry out the reflux reaction. After the reflux reaction was completed, it was naturally cooled to room temperature, and then saturated NaHCO3 solution was added for neutralization. Subsequently, an ice-water mixture was added to the flask to allow the mixture to crystallize. The mixture was filtered, and then washed successively with pure water and ethanol, and then dried under vacuum to obtain the dimethyl 2,9-dicarboxylic acid-1,10-o-phenanthroline.

[0055] After obtaining dimethyl 2,9-dicarboxy-1,10-o-phenanthroline, the present invention mixes the dimethyl 2,9-dicarboxy-1,10-o-phenanthroline, the substituted raw material, and an organic solvent to carry out a substitution reaction to obtain the DAPhen ligand; the substituted raw material includes one or more of 3-amino-1-propanol, 3-amino-1,2-propanediol, 2-(2-aminoethoxy)ethanol, and 2-(2-(2-aminoethoxy)ethoxy)ethanol.

[0056] In this invention, the temperature of the substitution reaction is preferably 60-80°C, specifically 60, 65, 70, 75 or 80°C, and the time is preferably 6-12 hours, specifically 6, 7, 8, 9, 10, 11 or 12 hours.

[0057] In this invention, the substitution reaction preferably includes a post-processing step to obtain the DAPhen ligand.

[0058] In this invention, the post-processing preferably includes one or more of rotary evaporation, washing, column chromatography purification, and drying. This invention does not impose any special limitations on the specific parameters of the post-processing, as long as the DAPhen ligand can be obtained.

[0059] This invention also provides the application of the DAPhen ligand described in the above technical solution in the separation of lanthanides and actinides.

[0060] This invention also provides a method for separating lanthanides and actinides from waste liquid, comprising the following steps:

[0061] The waste liquid is mixed with an extractant for solvent extraction, wherein the extractant is the DAPhen ligand described in the above technical solution, and the waste liquid contains lanthanide and actinide elements.

[0062] In this invention, the waste liquid is preferably a high-level radioactive waste liquid, which refers to waste liquid with a radioactivity greater than 3.7 × 10⁻⁶. 10 The radioactive waste liquid of Bq / L is preferably derived from the raffinate phase of the co-decontamination cycle section of a spent fuel reprocessing plant, and the acidity of the high-level radioactive waste liquid is preferably 3-4M.

[0063] In this invention, the lanthanide elements include europium (Eu), and the actinide elements include americium (Am).

[0064] In this invention, the acidity of the waste liquid is preferably 0.01 to 4 M, specifically 0.01, 0.05, 0.10, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 3, or 4 M. This invention preferably uses nitric acid to adjust the acidity of the waste liquid.

[0065] In this invention, the concentration of DAPhen ligand in the system during solvent extraction is 2.5–40 mM, specifically: L-1: 2.5, 5, 10, 20, and 25 mM; L-2: 2.5, 5, 10, 20, 25, and 30 mM; L-3: 2.5, 5, 10, 20, 25, 30, and 40 mM; L-4: 2.5, 5, 10, 20, 25, and 30 mM.

[0066] In this invention, the solvent extraction temperature is preferably room temperature, and the extraction time is preferably 5 to 60 minutes, specifically 5, 10, 15, 30, 45 or 60 minutes.

[0067] In this invention, the solvent extraction is preferably carried out under stirring conditions, and the stirring speed is preferably 3000 rpm.

[0068] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0069] Example 1

[0070] 1. Preparation of DAPhen ligands as shown in formulas L-1 to L-4;

[0071] a: Dimethyl-2,9-dicarboxy-1,10-o-phenanthroline

[0072]

[0073] 2,9-Dicarboxylic acid-1,10-o-phenanthroline (5 g, 18.64 mmol) and 15 mL of methanol were added to a 250 mL round-bottom flask. A magnetic stir bar was added, and then 2 mL of concentrated sulfuric acid (98 wt%) was slowly added dropwise to the reaction mixture. The reaction mixture was heated to 100 °C and refluxed for 6 h, then cooled to room temperature and neutralized with saturated NaHCO3 solution. Subsequently, 60 mL of an ice-water mixture was added to the flask to allow crystallization. The mixture was filtered and washed with pure water (5 × 20 mL) and ethanol (5 × 20 mL). After drying under vacuum at 70 °C, 4.1 g of a grayish-white solid product was obtained (yield 75%).

[0074] 1 H NMR (400MHz, DMSO) δ (ppm): 8.73-8.71 (d, J = 8.3Hz, 2H), 8.40-8.38 (d, J = 8.2Hz, 2H), 8.18 (s, 2H), 4.02 (s, 6H); 13 C NMR (400MHz, DMSO) δ (ppm): 165.52 (2C), 147.68 (2C), 145.06 (2C), 138.08 (2C), 130.58 (2C), 128.54 (2C), 123.70 (2C), 52.74 (2C); MS (ESI + )m / z calcd.for[M+H] + :297.09,found:297.0869;MS(ESI + )m / z calcd.for[M+Na] + :319.07,found:319.0688;MS(ESI + )m / z calcd.for[2M+Na] + :615.15,found:615.1493.

[0075] b: L-1(HP-DAPhen)

[0076]

[0077] Dimethyl-2,9-dicarboxylic acid-1,10-o-phenanthroline (2 g, 6.75 mmol) and 3-amino-1-propanol (1.08 g, 14.18 mmol) were added to a 100 mL round-bottom flask, along with 30 mL of methanol and a suitable magnetic stir bar. The mixture was heated and refluxed at 75 °C with stirring for 12 h. The solvent was removed by rotary evaporation, and the crude product was washed with ethanol (3 × 20 mL). After vacuum drying at 70 °C, 2.12 g of a white solid product was obtained (yield 82%).

[0078] Elemental Analysis calcd.for:C,62.82;H,5.80;N,14.65;O,16.73, Found:C,62.94;H,5.57;N,13.23; 1 H NMR (400MHz, DMSO) δ (ppm): 9.46-9.43 (m, 2H), 8.72-8.70 (d, J = 8.3Hz, 2H), 8.45-8.43 (d, J = 8.2H) z,2H),8.15(s,2H),4.80-4.77(m,2H),3.65-3.61(m,4H),3.58-3.53(m,4H),1.87-1.81(m,4H); 13 C NMR (400MHz, DMSO) δ (ppm): 163.58 (2C), 149.60 (2C), 143.58 (2C), 138.16 (2C), 1 30.13(2C),127.78(2C),120.87(2C),59.57(2C),37.25(2C),32.04(2C); MS(ESI + )m / z calcd.for[M+H] + :383.17,found:383.1708;MS(ESI + )m / z calcd.for[M+Na] + :405.15,found:405.1532; HRMS(ESI + )m / z calcd.for[M+H] + :383.17,found:383.1708; HRMS(ESI + )m / z calcd.for[M+Na] + :405.15,found:405.1532.

[0079] L-2(DHP-DAPhen)

[0080]

[0081] Dimethyl-2,9-dicarboxylic acid-1,10-o-phenanthroline (1 g, 3.38 mmol) and 3-amino-1,2-propanediol (0.66 g, 7.09 mmol) were added to a 100 mL round-bottom flask, along with 10 mL of MeOH and a suitable stir bar. The mixture was heated and refluxed at 75 °C for 12 h with stirring. The solvent was removed using a rotary evaporator, and the crude product was washed with ethanol (3 × 10 mL). After drying under vacuum at 70 °C, 1.17 g of a white solid product was obtained (yield 84%).

[0082] Elemental Analysis calcd.for:C,57.97;H,5.35;N,13.52;O,23.16,Found:C,56.70;H,5.14;N,11.87; 1 H NMR(400MHz,DMSO)δ(ppm):9.22-9.19(m,2H),8.72-8.70(d,J=8.3Hz,2H),8.44-8.42(d,J=8.2Hz,2H),8.15(s,2H),5.16(s,2H),4.88(s,2H),3.82-3.81(d,J=5.5Hz,2H),3.66-3.60(m,2H),3.56-3.44(m,6H); 13 C NMR(600MHz,DMSO)δ(ppm):163.67(2C),149.32(2C),143.42(2C),138.32(2C),130.20(2C),127.86(2C),120.86(2C),70.01(2C),64.39(2C),42.91(2C);MS(ESI + )m / z calcd.for[M+H] + :415.16,found:415.1604;MS(ESI + )m / z calcd.for[M+Na] + :437.14,found:437.1427;MS(ESI + )m / zcalcd.for[M+K] + :453.12,found:453.1159;MS(ESI + )m / z calcd.for[2M+Na] + :851.30,found:851.2962;HRMS(ESI + )m / z calcd.for[M+H] + :415.16,found:415.1604;HRMS(ESI + )m / z calcd.for[M+Na] + :437.14,found:437.1427;HRMS(ESI + )m / z calcd.for[M+K] + :453.12,found:453.1159.

[0083] L-3(AE-DAPhen)

[0084]

[0085] Dimethyl-2,9-dicarboxylic acid-1,10-o-phenanthroline (1 g, 3.38 mmol) and 2-(2-aminoethoxy)ethanol (0.76 g, 7.09 mmol) were added to a 100 mL round-bottom flask, along with 10 mL of MeOH and a stir bar. After heating and stirring at 75 °C for 12 h, the solvent was removed using a rotary evaporator. The starting material was washed with ethanol (3 × 20 mL) to obtain 0.90 g of the first fraction, a pure white product. The filtrate was evaporated and purified by column chromatography using 10 vol% methanol in dichloromethane as the mobile phase (rf = 0.41) to obtain a second fraction, 0.40 g of product. Both fractions were collected together and dried under vacuum at 70 °C, yielding 1.27 g of a white solid product (85% yield).

[0086] Elemental Analysis calcd.for:C,59.72;H,5.92;N,12.66;O,21.69, Found:C,58.78;H,5.76;N,11.43; 1 H NMR (400MHz, DMSO) δ (ppm): 9.38 (s, 2H), 8.74-8.72 (d, J = 7.4Hz, 2H), 8.46-8.44 (d ,J=7.3Hz,2H),8.18(s,2H),4.66(s,2H),3.70-3.66(d,J=20Hz,8H),3.52(s,8H); 13 C NMR (400MHz, DMSO) δ (ppm): 164.54 (2C), 150.16 (2C), 144.22 (2C), 138.80 (2C), 130.81 (2C),128.47(2C),121.64(2C),100.01(2C),72.59(2C),69.35(2C),60.76(2C); MS(ESI + )m / z calcd.for[M+H] + :443.19,found:443.1924;MS(ESI + m / zcalcd.for[M+Na] + :465.18,found:465.1747;MS(ESI + )m / z calcd.for[2M+Na] + :907.36,found:907.3614; HRMS(ESI +)m / z calcd.for[M+H] + :443.19,found:443.1924; HRMS(ESI + )m / z calcd.for[M+Na] + :465.18,found:465.1747.

[0087] L-4(AEE-DAPhen)

[0088]

[0089] Dimethyl-2,9-dicarboxylic acid-1,10-phenanthroline (compound 1, 1 g, 3.38 mmol) and 2-(2-(2-aminoethoxy)ethoxy)ethanol (1.08 g, 7.09 mmol) were added to a 100 mL round-bottom flask, along with 10 mL of MeOH and a suitable stir bar. After heating and stirring at 75 °C for 12 h, the solvent was removed using a rotary evaporator. The product was then purified by chromatography using 10 vol% MeOH in DCM as the mobile phase (rf = 0.39) to give 1.43 g of a clean, oily product (yield 80%).

[0090] Elemental Analysis calcd.for:C,58.86;H,6.46;N,10.56;O,24.12, Found:C,56.38;H,6.42;N,9.46; 1 H NMR (400MHz, DMSO) δ (ppm): 9.37-9.34 (m, 2H), 8.73-8.71 (d, J = 8.3Hz, 2H), 8.46-8.44 (d, J = 8.3Hz, 2H), 8.16 (s, 2H) ,4.55-4.52(m,2H),3.72-3.69(m,4H),3.66-3.63(m,4H),3.62-3.59(m,4H),3.56-3.54(m,4H),3.44-3.40(m,8H); 13 C NMR (400MHz, DMSO) δ (ppm): 164.03 (2C), 149.60 (2C), 143.68 (2C), 138.27 (2C), 130.28 (2C), 127.94(2C),121.10(2C),72.36(2C),69.73(2C),69.61(2C),68.81(2C),60.19(2C); MS(ESI + )m / z calcd.for[M+H] + :531.25,found:531.2444,MS(ESI+ )m / z calcd.for[M+K] + :569.20found:569.2002; HRMS(ESI + )m / z calcd.for[M+H] + :531.25,found:531.2444,HRMS(ESI + )m / z calcd.for[M+K] + :569.20found:569.2002.

[0091] 2. Solvent Extraction Test

[0092] 2.1 Solvent Extraction

[0093] The HNO3 used was analytical grade. The deionized water used had low conductivity (18.2 MΩ). The 241Am tracer (americium tracer) used was obtained from the Institute of Nuclear and New Energy Technology, Tsinghua University, with a radioactivity concentration of 1 × 10⁻⁶. 7 cpm / mL. The radioactive europium tracer containing 152Eu and 154Eu was obtained from the Institute of Nuclear and New Energy Technology, Tsinghua University, with a total radioactive concentration of 1.6 × 10⁻⁶ cpm / mL. 7 cpm / mL.

[0094] All ligands were tested by elemental analysis, and their purity was determined taking into account the water content. Ligand 1 had a purity of 90 wt%. Ligand 2 had a purity of 91 wt%. Ligand 3 had a purity of 92 wt%. Ligand 4 had a purity of 92.8 wt%.

[0095] All aqueous phases contained ligands, 241Am and 152Eu / 154Eu tracers, and different concentrations of HNO3.

[0096] All extraction experiments were performed in 4 mL polypropylene screw-cap vials with rubber O-rings to prevent leakage / contamination. The activities of 241Am and 152 / 154Eu were counted using a Quantulis 1220 (PerkinElmer) liquid scintillation counter.

[0097] 2.2 Stock solution

[0098] A ligand stock solution was prepared by dissolving 136 mg of HP-DAPhen ligand (purity: 90 wt%) in 8 mL of pure water, resulting in a concentration of 40 mM.

[0099] A ligand stock solution was prepared by dissolving 145.7 mg of DHP-DAPhen ligand (purity: 91 wt%) in 8 mL of pure water, resulting in a concentration of 40 mM.

[0100] A ligand stock solution was prepared by dissolving 153.9 mg of AE-DAPhen ligand (purity: 92 wt%) in 8 mL of pure water, resulting in a concentration of 40 mM.

[0101] A ligand stock solution was prepared by dissolving 183 mg of AEE-DAPhen ligand (purity: 92.8 wt%) in 8 mL of pure water, resulting in a concentration of 40 mM.

[0102] 241Am(NO3)3 stock solution containing 0.01M nitric acid.

[0103] A 152 / 154 Eu(NO3)3 stock solution containing 0.01M nitric acid.

[0104] HNO3 stock solutions are available in 1M, 4M, and 8M.

[0105] 0.2M TODGA (N,N,N′,N′-tetraoctyl-3-oxopramethylenediamide) organic phase: 3.521 g of TODGA was dissolved in 30 mL of kerosene / n-octanol (95:5, v / v) solution; the structure of TODGA is shown below:

[0106]

[0107] 2.3 Three types of tests:

[0108] 2.3.1 Acidity test to determine the effect of nitric acid concentration on the partition ratio and SF. Eu / Am The impact.

[0109] For all ligands, acidity studies were conducted at nitric acid concentrations of 0.01, 0.05, 0.10, 0.25, 0.5, 0.75, 1.0, 1.25, and 1.5 M, with a standard concentration of 10 mM for the ligands.

[0110] 2.3.2 Kinetic studies were conducted to determine the kinetics of the extraction process.

[0111] The aqueous phase contained a constant concentration of ligand (10 mM) and 0.75 M nitric acid, and tests were performed at 5, 10, 15, 30, 45 and 60 min.

[0112] 2.3.3 Ligand concentration extraction studies were conducted to determine the ligand concentration-partition ratio and SF. Eu / Am The effect of acidity is constant at 0.75M nitric acid.

[0113] HP-DAPhen: 2.5, 5, 10, 20 and 25 mM;

[0114] DHP-DAPhen: 2.5, 5, 10, 20, 25 and 30mM;

[0115] AE-DAPhen: 2.5, 5, 10, 20, 25, 30 and 40mM;

[0116] AEE-DAPhen: 2.5, 5, 10, 20, 25 and 30mM.

[0117] Mix 1 mL of aqueous phase and 1 mL of organic phase in a PP vial, vortex (standard 30 min), and then centrifuge (3000 rpm, 2 min) to completely separate the two phases. Samples from both the aqueous and organic phases are then collected, and the radioactivity in different channels is counted using LSC to distinguish between alpha radioactivity of 241 Am and beta radioactivity of 152 Eu / 154 Eu. To ensure data accuracy, measurements are performed on each sample for at least 5 min. The count ratios in the two phases are then interpreted as extraction parameter D. Am and D Eu , and SF Eu / Am The calculation is D. Eu / D Am Compare.

[0118] 2.3 Solvent Extraction Results

[0119] Figure 2 The acidity test curve for HP-DAPhen is shown. Figure 3 The extraction curves show the ligand concentrations of HP-DAPhen. Figure 4 The kinetic test curves for HP-DAPhen show that the optimal acidity for HP-DAPhen is 0.50–1.0 M, resulting in good separation performance. SF Eu / Am The value is 200-300, and the equilibration time is good, less than 10 minutes.

[0120] Figure 5 The acidity test curve for DHP-DAPhen is shown. Figure 6 Extraction curves for DHP-DAPhen ligand concentrations. Figure 7 The kinetic test curves for DHP-DAPhen show that the optimal acidity for DHP-DAPhen is 0.5–1.0 M, resulting in good separation performance. SF Eu / Am The temperature ranges from 150 to 230, and the equilibration time is good, less than 10 minutes.

[0121] Figure 8 The acidity test curve for AE-DAPhen is shown. Figure 9 The extraction curves show the ligand concentrations of AE-DAPhen. Figure 10 The kinetic test curves for AE-DAPhen show that the optimal acidity for AE-DAPhen is 0.5–1.0 M, resulting in good separation performance.Eu / Am The temperature ranges from 200 to 320, and the equilibration time is good, less than 10 minutes.

[0122] Figure 11 The acidity test curve for AEE-DAPhen is shown. Figure 12 The extraction curves show the ligand concentrations of AEE-DAPhen. Figure 13 The kinetic test curves for AEE-DAPhen show that the optimal acidity for AEE-DAPhen is 0.5–1.0 M, resulting in good separation performance. SF Eu / Am The temperature ranges from 200 to 290, and the equilibration time is good, less than 10 minutes.

[0123] In summary, this invention starts with the design of ligand molecular structures and develops four new DAPhen ligands. These ligands ensure a high partition ratio for Eu, while the introduction of water-soluble ligands also guarantees efficient back-extraction of Am. The lanthanum-actinium separation factor (SF) of the four DAPhen ligands is [not specified]. Eu / Am The separation effect was good at temperatures between 200 and 300 °C. Furthermore, the ligand exhibited good water solubility and extraction kinetics, reaching equilibrium within 10 minutes. This invention provides new insights into lanthanum-actinium separation and offers technical support for establishing advanced spent nuclear fuel reprocessing systems and efficiently utilizing minor actinides.

[0124] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A DAPhen ligand, characterized in that, It has the structure shown in Equation L-3:

2. The method for preparing DAPhen ligand according to claim 1, characterized in that, Includes the following steps: 2,9-dicarboxylic acid-1,10-o-phenanthroline, an organic solvent, and an acidic substance were mixed and refluxed to give dimethyl 2,9-dicarboxylic acid-1,10-o-phenanthroline. The dimethyl 2,9-dicarboxy-1,10-o-phenanthroline, the substituted raw material, and an organic solvent were mixed and subjected to a substitution reaction to obtain the DAPhen ligand; the substituted raw material was 2-(2-aminoethoxy)ethanol.

3. The preparation method according to claim 2, characterized in that, The reflux reaction is carried out at a temperature of 60–100°C for a duration of 6–12 hours.

4. The preparation method according to claim 2, characterized in that, The substitution reaction is carried out at a temperature of 60–80°C for a time of 6–12 hours.

5. The application of the DAPhen ligand as described in claim 1 in the separation of lanthanides and actinides.

6. A method for separating lanthanides and actinides from waste liquid, characterized in that, Includes the following steps: The waste liquid is mixed with an extractant for solvent extraction, wherein the extractant is the DAPhen ligand as described in claim 1, and the waste liquid contains lanthanide and actinide elements.

7. The method according to claim 6, characterized in that, The lanthanides include europium, and the actinides include americium.

8. The method according to claim 6, characterized in that, The acidity of the waste liquid is 0.01 to 4 M.

9. The method according to claim 6, characterized in that, The concentration of DAPhen ligand in the system during solvent extraction is 2.5–40 mM.

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