Application of ionic liquid in separation and solidification of pertechnetate in aqueous solution

Abstract

The invention relates to the technical field of wastewater treatment, in particular to application of ionic liquid in separation and solidification of pertechnetate radicals in an aqueous solution. The invention provides an application of an ionic liquid in separation and solidification of pertechnetate radicals in an aqueous solution. The ionic liquid has a structure as shown in any one of formulas 1-4. According to the invention, anions in the ionic liquid with the structures as shown in the formulas 1-4 are modified by amido functional groups, so that the extraction of pertechnetate radicals can be realized; dimethyl dioctadecyl ammonium with a relatively long chain length is selected as a cation of the ionic liquid, so that the whole ionic liquid is controlled to have proper surface activity. And after the technetium is extracted in the liquid-liquid extraction system, the solubility of the ionic liquid with the technetium is changed, and the technetium is separated out from an organic phase in a solid form.

Description

Technical Field

[0002] This invention relates to the field of wastewater treatment technology, and in particular to the application of an ionic liquid in the separation and solidification of pertechnetate in aqueous solutions. Background Technology

[0003] 99m Technetium (Tc) is one of the most widely used medical isotopes in clinical practice (with over 40 million uses globally annually), making its waste management particularly important. Currently, medical institutions generally adopt a storage-decay-discharge strategy for technetium-containing waste, that is, allowing it to decay naturally. 99m Tc is released after its radioactivity decreases to an exempt level. However, this method is inefficient, requiring significant time, space, and administrative resources. More importantly, 99m decay products of T 99 Tc is a long-life β - Radioactive nuclides with a half-life as long as 2.13 × 10⁻⁶. 5 Over time, its long-term accumulation in the environment poses a potential threat to ecosystems and public health. Therefore, the proactive separation and recycling of medical waste... 99m Tc / 99 Tc can effectively reduce the cost of waste liquid treatment and disposal, while reducing potential nuclear environmental safety risks.

[0004] In the waste liquid, 99 Among existing methods for separating the dominant chemical form of technetium, pertechnetate ion Tc(VII), solvent extraction is one of the most promising technical routes for practical application. However, compared to solid adsorbents (such as MOF, COF, ion exchange resins, etc.), solvent extraction usually requires continuous extraction-back-extraction, concentration, and other post-processing steps to achieve the final purification of technetium, resulting in a complex overall process and significantly increasing the generation of secondary waste. Therefore, a breakthrough is urgently needed for novel extractants that combine high separation efficiency with simplified subsequent purification processes. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an application of ionic liquid in the separation and solidification of pertechnetate in aqueous solutions. The ionic liquid exhibits excellent separation and solidification effects on pertechnetate, and it transfers the extracted technetium to the solid phase at the water-oil interface, enabling technetium recovery without subsequent post-processing steps.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an application of an ionic liquid in the separation and solidification of pertechnetate in an aqueous solution, wherein the ionic liquid has the structure shown in any one of Formulas 1 to 4: Formula 1, Equation 2, Formula 3, Formula 4.

[0007] Preferably, the method of application includes the following steps: The solution of the ionic liquid and the solution containing pertechnetate were mixed and extracted.

[0008] Preferably, the pH value of the extraction is 1 to 11.

[0009] Preferably, the pH value of the extraction is 5 to 8.

[0010] Preferably, the concentration of the ionic liquid in the solution is 1~10 mmol / L; The concentration of pertechnetate in the solution is 10. -6 ~10 -4 mol / L.

[0011] Preferably, the volume ratio of the ionic liquid solution to the solution containing pertechnetate is (0.8~1.2):1.

[0012] Preferably, the extraction method includes standing or shaking.

[0013] Preferably, when the extraction method is oscillation, the oscillation frequency is 60~120 rpm and the time is 0.5~2h.

[0014] Preferably, after the oscillation is completed, centrifugation is also included; The centrifugation speed is 4000~12000 rpm, and the time is 3~15 min.

[0015] Preferably, the settling time is 3 to 7 days.

[0016] This invention provides an application of an ionic liquid in the separation and solidification of pertechnetate in an aqueous solution, wherein the ionic liquid has the structure shown in any one of Formulas 1 to 4: Formula 1, Equation 2, Formula 3, Formula 4.

[0017] The anions in the ionic liquids of Formulas 1 to 4 described in this invention are modified with amide functional groups to achieve the extraction of pertechnetium ions. Dimethyl dioctadecylammonium, with a relatively long chain, is selected as the cation of the ionic liquid to control the overall surface activity of the ionic liquid to a suitable level. After the extraction of technetium, the solubility of the extracted technetium in the ionic liquid changes, and it precipitates from the organic phase in solid form. In other words, the ionic liquid can achieve the separation and solidification of pertechnetium ions in the aqueous phase in a single step within a liquid-liquid extraction system. While the ionic liquid extracts technetium, due to the change in its surface activity / amphiphilicity, it precipitates from the organic phase, causing the extracted technetium to be transferred to the solid phase at the water-oil interface. This solid phase contains only C, H, O, and N, making it environmentally friendly. Compared to traditional extractants, the ionic liquid of this invention can greatly simplify the separation steps of pertechnetium ions, better serving the purpose of subsequent waste disposal or recycling. Attached Figure Description

[0018] Figure 1 The proton NMR spectrum of [D1821][iso-SCA-C4]; Figure 2 The proton NMR spectrum of [D1821][n-SCA-C4]; Figure 3 The proton NMR spectrum of [D1821][iso-SCA-C8]; Figure 4 The proton NMR spectrum of [D1821][n-SCA-C8]; Figure 5 The curing rates are those of Examples 1-1 to 1-9; Figure 6 The curing rates of Examples 2-1 to 2-9; Figure 7 The curing rates of Examples 3-1 to 3-9; Figure 8 The curing rates of Examples 4-1 to 4-9; Figure 9 The images are SEM images of the solids obtained after extraction as described in Examples 1-4 at different magnifications. Figure 10 Fourier transform infrared spectra of the solids obtained after extraction as described in Examples 1-4; Figure 11 This is a physical diagram of the extraction process described in this invention, which involves extraction under static and agitation conditions. Detailed Implementation

[0019] This invention provides an application of an ionic liquid in the separation and solidification of pertechnetate in an aqueous solution, wherein the ionic liquid has the structure shown in any one of Formulas 1 to 4: Formula 1, Equation 2, Formula 3, Formula 4.

[0020] In this invention, the compound having the structure shown in Formula 1 is called N,N-diisobutylsuccinic anhydride ionic liquid, denoted as [D1821][iso-SCA-C4]; The compound having the structure described in Formula 2 is called N,N-di-n-butylsuccinic anhydride ionic liquid, denoted as [D1821][n-SCA-C4]; The compound having the structure described in Formula 3 is called N,N-diisooctylsuccinic anhydride ionic liquid, denoted as [D1821][iso-SCA-C8]; The compound having the structure described in Formula 2 is called N,N-di-n-octylsuccinic anhydride ionic liquid, denoted as [D1821][n-SCA-C8].

[0021] In this invention, when the ionic liquid is [D1821][iso-SCA-C4], the preparation method of [D1821][iso-SCA-C4] preferably includes the following steps: Succinic anhydride solution, dialkyl chain amine and diisobutylamine solution were mixed and subjected to ring-opening condensation reaction to obtain N,N-diisobutylsuccinic acid; The N,N-diisobutylsuccinic acid was mixed with water to obtain an aqueous solution of N,N-diisobutylsuccinic acid. The aqueous solution of N,N-diisobutylsuccinic acid, sodium hydroxide and dimethyl dioctadecyl ammonium chloride solution were mixed to obtain the [D1821][iso-SCA-C4].

[0022] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0023] This invention involves mixing succinic anhydride solution, dialkyl chain amine, and diisobutylamine solution to perform a ring-opening condensation reaction to obtain N,N-diisobutylsuccinic acid.

[0024] In this invention, the concentration of succinic anhydride in the succinic anhydride solution is preferably 0.6 mol / L.

[0025] In this invention, the solvent in the succinic anhydride solution is preferably methyl tert-butyl ether.

[0026] In this invention, the concentration of diisobutylamine in the diisobutylamine solution is preferably 14-17 mmol / L, more preferably 14 mmol / L, 15 mmol / L, 16 mmol / L, or 17 mmol / L. In an embodiment of this invention, the concentration of diisobutylamine in the diisobutylamine solution can be 16 mmol / L.

[0027] In this invention, the solvent in the diisobutylamine solution is preferably methyl tert-butyl ether.

[0028] In this invention, the molar ratio of succinic anhydride, dialkyl amine, and diisobutylamine in the succinic anhydride solution is preferably 1:(1.1~1.3), more preferably 1:1.1, 1:1.2, or 1:1.3. In embodiments of this invention, the molar ratio of succinic anhydride, dialkyl amine, and diisobutylamine in the succinic anhydride solution can be 1:1.2.

[0029] In this invention, the mixing process is preferably as follows: under stirring conditions, a dialkyl chain amine and a diisobutylamine solution are sequentially added to a succinic anhydride solution. In this invention, the stirring time is preferably 15 minutes. This invention does not impose any special limitations on the method of adding the dialkyl chain amine; any method well-known to those skilled in the art can be used. In this invention, the diisobutylamine solution is preferably added dropwise. In an embodiment of this invention, the mixing process can be as follows: a succinic anhydride solution is placed in a round-bottom flask, a dialkyl chain amine is added under stirring conditions, and then the diisobutylamine solution is transferred using a pipette and loaded into a constant-pressure separatory funnel, added to the round-bottom flask at a rate of one drop per second.

[0030] In this invention, the ring-opening condensation reaction is preferably carried out under stirring conditions. The stirring temperature is preferably 25~30℃, more preferably 25℃, 26℃, 27℃, 28℃, 29℃ or 30℃; the stirring speed is preferably 600~1200 r / h, more preferably 600 r / h, 700 r / h, 800 r / h, 900 r / h, 1000 r / h, 1100 r / h or 1200 r / h; and the stirring time is preferably 6~12h, more preferably 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0031] After the ring-opening condensation reaction is completed, the present invention preferably includes sequential acid treatment, static separation, acid washing, water washing, drying, filtration, and vacuum distillation. In the present invention, the acid solution used for the acid treatment is preferably hydrochloric acid with a mass concentration of 5%. The acid treatment is preferably performed by adding the acid solution to the product system obtained from the ring-opening condensation reaction. The acid treatment is carried out under stirring conditions, and the stirring time is preferably 5 minutes. In the present invention, the purpose of the acid treatment is to remove excess reaction byproducts and unreacted raw materials. In the present invention, the static separation is preferably carried out in a separatory funnel. The present invention does not impose any special limitations on the static separation process; any process well known to those skilled in the art can be used. In the present invention, after static separation, the aqueous phase is removed, and the organic phase is retained. Therefore, in the present invention, the target of the acid washing is preferably the organic phase obtained from the static separation; the acid solution used is preferably hydrochloric acid, and the number of acid washings is preferably 2-3 times. In the present invention, the water used for the water washing is preferably ultrapure water, and the number of water washings is preferably 1-3 times. In the present invention, the purpose of the water washing is to remove residual acid from the organic phase. In this invention, the drying is preferably carried out using anhydrous magnesium sulfate; this invention does not impose any special limitations on the filtration and vacuum distillation processes, and any process well known to those skilled in the art can be used.

[0032] After obtaining the N,N-diisobutylsuccinic acid, the present invention mixes the N,N-diisobutylsuccinic acid with water to obtain an aqueous solution of N,N-diisobutylsuccinic acid.

[0033] In this invention, the water is preferably ultrapure water.

[0034] In this invention, the preferred ratio of N,N-diisobutylsuccinic acid to water is 20 mmol: 10 mL.

[0035] The present invention does not impose any special limitations on the mixing process; any process known to those skilled in the art can be used.

[0036] After obtaining the aqueous solution of N,N-diisobutylsuccinic acid, the present invention mixes the aqueous solution of N,N-diisobutylsuccinic acid, sodium hydroxide and dimethyl dioctadecyl ammonium chloride solution to obtain the [D1821][iso-SCA-C4].

[0037] In this invention, the concentration of dimethyl dioctadecyl ammonium chloride in the dimethyl dioctadecyl ammonium chloride solution is preferably 1 mol / L. In this invention, the solvent in the dimethyl dioctadecyl ammonium chloride solution preferably includes methyl tert-butyl ether.

[0038] In this invention, the molar ratio of N,N-diisobutylsuccinic acid in the aqueous solution of N,N-diisobutylsuccinic acid, sodium hydroxide, and dimethyl dioctadecyl ammonium chloride in the solution of dimethyl dioctadecyl ammonium chloride is preferably 20:22:20.

[0039] In this invention, the mixing preferably includes: mixing the aqueous solution of N,N-diisobutylsuccinic acid and sodium hydroxide to start the reaction, and after the solution changes from turbid to clear, mixing the resulting intermediate aqueous solution with the dimethyl dioctadecyl ammonium chloride solution.

[0040] After the mixing is completed, the present invention preferably includes continued stirring, and the continued stirring time is preferably 48 hours.

[0041] After the stirring is completed, the present invention preferably further includes transferring the obtained product system to a separatory funnel, removing the lower aqueous phase, and measuring chloride ions; if chloride ions can be detected with silver nitrate solution (resulting in a white precipitate), the organic phase solution is further extracted with ultrapure water until chloride ions are no longer detectable in the aqueous phase. In the present invention, chloride ion detection is performed by dynamically monitoring the reaction using thin-layer chromatography.

[0042] In this invention, when the ionic liquid is [D1821][n-SCA-C4], the preparation method of [D1821][n-SCA-C4] preferably refers to the preparation process described above, except that diisobutylamine is replaced with di-n-butylamine.

[0043] In this invention, when the ionic liquid is [D1821][iso-SCA-C8], the preparation method of [D1821][iso-SCA-C8] preferably refers to the preparation process described above, except that diisobutylamine is replaced with diisooctylamine.

[0044] In this invention, when the ionic liquid is [D1821][n-SCA-C8], the preparation method of [D1821][n-SCA-C8] preferably refers to the preparation process described above, except that diisobutylamine is replaced with di-n-octylamine.

[0045] In this invention, the method of application includes the following steps: The solution of the ionic liquid and the solution containing pertechnetate were mixed and extracted.

[0046] In this invention, the concentration of the ionic liquid in the solution is preferably 1 to 10 mmol / L, more preferably 1 mmol / L, 2 mmol / L, 3 mmol / L, 4 mmol / L, 5 mmol / L, 6 mmol / L, 7 mmol / L, 8 mmol / L, 9 mmol / L or 10 mmol / L.

[0047] In this invention, the concentration of pertechnetate in the solution containing pertechnetate is preferably 10. -6 ~10 -4 mol / L, more preferably 10 mol / L -6 mol / L, 10 -5 mol / L, 10 -4 mol / L or 5×10 -4 mol / L.

[0048] In this invention, the volume ratio of the ionic liquid solution to the solution containing pertechnetate is preferably 1:1.

[0049] The present invention does not impose any special limitations on the mixing process; any process known to those skilled in the art can be used.

[0050] In this invention, the pH value of the extraction is preferably 1 to 11, and more preferably 5 to 8.

[0051] In this invention, the extraction method preferably includes standing or shaking; such as Figure 11 As shown in a, when the extraction method is preferably oscillation, the oscillation frequency is preferably 60-120 rpm, more preferably 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, or 120 rpm; the oscillation time is preferably 0.5-2 h, more preferably 0.5 h, 1 h, 1.5 h, or 2 h. After the oscillation is completed, the present invention also preferably includes centrifugation, the centrifugation speed is preferably 4000-12000 rpm, more preferably 4000 rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm, 11000 rpm, or 12000 rpm; the centrifugation time is preferably 3-15 min, more preferably 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, or 15 min. In this invention, when the two solutions are mixed under shaking conditions, the formation of white vesicles can be observed at the interface immediately. After constant temperature shaking, a large amount of white foam can be seen in the test tube. After centrifugation, a layer of white solid can be seen at the interface of the two phases.

[0052] like Figure 11 As shown in b, when the extraction method is preferably static, the static time is preferably 3 to 7 days, more preferably 3, 4, 5, 6, or 7 days. In this invention, extraction is performed under static conditions, and after 3 weeks of static standing, no change was observed in the generated white solid layer.

[0053] 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.

[0054] Since technetium is radioactive, perrhenate is used for verification experiments because its chemical properties are basically the same (this method is very common in the field of technetium separation research and its reliability has been fully confirmed).

[0055] The preparation method of [D1821][iso-SCA-C4] is as follows: 24 mmol of succinic anhydride is placed in a round-bottom flask, and 30 mL of methyl tert-butyl ether is added. After complete dissolution by stirring (for 15 min), 20 mmol of a dialkyl chain amine (diisobutylamine or diisooctylamine) is dissolved in 10 mL of methyl tert-butyl ether. The resulting diisobutylamine solution is loaded into a constant-pressure separatory funnel and added to the round-bottom flask at a rate of one drop per second to carry out the ring-opening condensation reaction. The stirring time was 9 hours. 10 mL of 5% hydrochloric acid was added and stirred for 5 minutes to remove excess reaction byproducts and unreacted raw materials. The mixture was then transferred to a separatory funnel and allowed to stand for separation. The aqueous phase was removed, and the resulting organic phase was washed three times with 40 mL of 5% hydrochloric acid. The remaining acid in the organic phase was removed with ultrapure water and washed three times. Finally, the organic phase was removed from the upper layer, dried with anhydrous magnesium sulfate, filtered, and then distilled under reduced pressure to obtain N,N-diisobutylsuccinic acid. 20 mmol of the N,N-diisobutylsuccinic acid was dissolved in 10 mL of ultrapure water, and 22 mmol of sodium hydroxide was added. After the reaction started, the solution changed from turbid to clear, resulting in an aqueous phase system. Then, 20 mmol of dimethyl dioctadecyl ammonium chloride was dissolved in 20 mL of methyl tert-butyl ether to obtain a dimethyl dioctadecyl ammonium chloride solution. The dimethyl dioctadecyl ammonium chloride solution was mixed with the aqueous phase system and stirred (for 48 h). The mixture was then transferred to a separatory funnel for separation. The lower aqueous phase was taken out to determine chloride ions. If chloride ions could be detected with silver nitrate solution (resulting in a white precipitate), the organic phase solution was further extracted with ultrapure water until chloride ions were no longer detectable in the aqueous phase. The reaction process was dynamically monitored using thin-layer chromatography during the synthesis process to obtain [D1821][iso-SCA-C4] (H NMR spectrum as shown). Figure 1 (as shown) The preparation method of [D1821][n-SCA-C4] is the same as that of [D1821][iso-SCA-C4], except that diisobutylamine is replaced with di-n-butylamine to obtain [D1821][n-SCA-C4] (H NMR spectrum as shown in the figure). Figure 2 (As shown).

[0056] The preparation method of [D1821][iso-SCA-C8] is the same as that of [D1821][iso-SCA-C4], except that diisobutylamine is replaced with diisooctylamine to obtain [D1821][iso-SCA-C8] (H NMR spectrum as shown in the figure). Figure 3 (As shown).

[0057] The preparation method of [D1821][n-SCA-C8] is the same as that of [D1821][iso-SCA-C4], except that diisobutylamine is replaced with di-n-octylamine to obtain [D1821][n-SCA-C8] (H NMR spectrum as shown in Figure 1). Figure 4 (as shown) 1 mmol of perrhenate was initially dissolved in ultrapure water in a small beaker, and then transferred to a 100 mL volumetric flask and diluted to volume to obtain a rhenium stock solution with a concentration of 0.01 mol / L. Dissolve 0.1 mmol of the ionic liquid in a beaker by adding tetradecane. Transfer the dissolved solution to a 100 mL volumetric flask to obtain a stock solution of the ionic liquid with a concentration of 0.01 mol / L.

[0058] Examples 1-1 to 1-9 like Figure 11 As shown in a, the 0.01 mol / L rhenium stock solution is diluted to a 0.0005 mol / L rhenium solution; The stock solution of the ionic liquid ([D1821][iso-SCA-C8]) with a concentration of 0.01 mol / L was diluted to a diluted ionic liquid solution with a concentration of 0.005 mol / L. 3 mL of the 0.005 mol / L ionic liquid dilution and 3 mL of the 0.0005 mol / L rhenium solution were mixed and extracted under shaking conditions (shaking frequency of 120 rpm for 30 min). After extraction, the mixture was centrifuged (centrifugation speed of 8000 rpm for 15 min) to obtain the solidified solid, aqueous phase and organic phase. The concentration of Re(VII) in the aqueous phase before and after extraction was measured, and then the solidification rate of Re(VII) was calculated (the concentration of Re(VII) entering the organic phase during the surface solidification process of the back-extraction time of the organic phase can be ignored). The curing rates of Examples 1-1 to 1-9 are as follows: Figure 5As shown, the curing rates of [D1821][iso-SCA-C8] under pH values ​​of 1, 4, 5, 6, 7, 8, 9, 10, and 11 were 96.59%, 96.49%, 97.22%, 97.80%, 97.40%, 97.25%, 96.59%, 95.14%, and 94.51%, respectively. The highest curing rate of [D1821][iso-SCA-C8] was 97.80% when the pH was 6.

[0059] Examples 2-1 to 2-9 The 0.01 mol / L rhenium stock solution was diluted to a 0.0005 mol / L rhenium solution. The stock solution of the ionic liquid ([D1821][n-SCA-C8]) with a concentration of 0.01 mol / L was diluted to a diluted ionic liquid solution with a concentration of 0.005 mol / L. 3 mL of the 0.005 mol / L ionic liquid dilution and 3 mL of the 0.0005 mol / L rhenium solution were mixed and extracted under shaking conditions (shaking frequency of 120 rpm for 30 min). After extraction, the mixture was centrifuged (centrifugation speed of 8000 rpm for 15 min) to obtain the solidified solid, aqueous phase and organic phase. The concentration of Re(VII) in the aqueous phase before and after extraction was measured, and then the solidification rate of Re(VII) was calculated (the concentration of Re(VII) entering the organic phase during the surface solidification process of the back-extraction time of the organic phase can be ignored). The curing rates of Examples 2-1 to 2-9 are as follows: Figure 6 As shown, the curing rates of [D1821][n-SCA-C8] under pH values ​​of 1, 4, 5, 6, 7, 8, 9, 10, and 11 are 95.34%, 96.72%, 96.71%, 97.42%, 96.64%, 96.60%, 95.80%, 95.95%, and 93.29%, respectively. When the pH is 6, the curing rate of [D1821][n-SCA-C8] is the highest at 97.54%.

[0060] Examples 3-1 to 3-9 The 0.01 mol / L rhenium stock solution was diluted to a 0.0005 mol / L rhenium solution. The stock solution of the ionic liquid ([D1821][iso-SCA-C4]) with a concentration of 0.01 mol / L was diluted to a diluted ionic liquid solution with a concentration of 0.005 mol / L. 3 mL of the 0.005 mol / L ionic liquid dilution and 3 mL of the 0.0005 mol / L rhenium solution were mixed and extracted under shaking conditions (shaking frequency of 120 rpm for 30 min). After extraction, the mixture was centrifuged (centrifugation speed of 8000 rpm for 15 min) to obtain the solidified solid, aqueous phase and organic phase. The concentration of Re(VII) in the aqueous phase before and after extraction was measured, and then the solidification rate of Re(VII) was calculated (the concentration of Re(VII) entering the organic phase during the surface solidification process of the back-extraction time of the organic phase can be ignored). The curing rates of Examples 3-1 to 3-9 are as follows: Figure 7 As shown, the curing rates of [D1821][iso-SCA-C4] under pH values ​​of 1, 4, 5, 6, 7, 8, 9, 10, and 11 were 95.95%, 96.01%, 96.95%, 97.44%, 97.14%, 96.68%, 96.33%, 96.05%, and 94.72%, respectively. The highest curing rate of [D1821][iso-SCA-C4] was 97.41% when the pH was 6.

[0061] Examples 4-1 to 4-9 The 0.01 mol / L rhenium stock solution was diluted to a 0.0005 mol / L rhenium solution. The stock solution of the ionic liquid ([D1821][n-SCA-C4]) with a concentration of 0.01 mol / L was diluted to a diluted ionic liquid solution with a concentration of 0.005 mol / L. 3 mL of the 0.005 mol / L ionic liquid dilution and 3 mL of the 0.0005 mol / L rhenium solution were mixed and extracted under shaking conditions (shaking frequency of 120 rpm for 30 min). After extraction, the mixture was centrifuged (centrifugation speed of 8000 rpm for 15 min) to obtain the solidified solid, aqueous phase and organic phase. The concentration of Re(VII) in the aqueous phase before and after extraction was measured, and then the solidification rate of Re(VII) was calculated (the concentration of Re(VII) entering the organic phase during the surface solidification process of the back-extraction time of the organic phase can be ignored). The curing rates of Examples 4-1 to 4-9 are as follows: Figure 8As shown, the curing rates of [D1821][n-SCA-C4] under pH values ​​of 1, 4, 5, 6, 7, 8, 9, 10, and 11 were 96.95%, 96.25293%, 97.21519%, 97.54%, 97.4%, 97.17%, 96.59%, 95.14%, and 94.92%, respectively. When the pH was 6, the curing rate of [D1821][n-SCA-C4] was the highest at 97.44%.

[0062] Test case The solids obtained after extraction as described in Examples 1-4 were subjected to SEM testing. Figure 9 The images shown are SEM images of the solids obtained after extraction as described in Examples 1-4 at different magnifications. Figure 9 As can be seen, the solid obtained after extraction in Examples 1-4 is layered with complex wrinkles on the surface and large areas of curling visible at the edges, and its morphology is similar to that of a folded film. The solids and ionic liquids obtained after extraction as described in Examples 1-4 were subjected to Fourier transform infrared spectroscopy (FTIR) analysis. Figure 10 The Fourier transform infrared spectra of the solids obtained after extraction as described in Examples 1-4 are obtained from... Figure 10 It can be seen that the solids obtained after extraction in Examples 1-4 are at 910 cm⁻¹ -1 Add ReO4 - Characteristic absorption peaks, based on the changes in carbonyl peaks before and after extraction and ReO4 - The appearance of the characteristic absorption peak suggests that Re(VII) coordinates with the carbonyl bond in the ionic liquid.

[0063] 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. An application of an ionic liquid in the separation and solidification of pertechnetate in aqueous solutions, characterized in that, The ionic liquid has the structure shown in any one of Formulas 1 to 4: Formula 1, Equation 2, Formula 3, Formula 4.

2. The application as described in claim 1, characterized in that, The method of application includes the following steps: The solution of the ionic liquid and the solution containing pertechnetate were mixed and extracted.

3. The application as described in claim 2, characterized in that, The pH value of the extraction is 1~11.

4. The application as described in claim 3, characterized in that, The pH value of the extraction is 5-8.

5. The application as described in claim 1, characterized in that, The concentration of the ionic liquid in the solution is 1~10 mmol / L; The concentration of pertechnetate in the solution is 10. -6 ~10 -4 mol / L.

6. The application as described in claim 5, characterized in that, The volume ratio of the ionic liquid solution to the solution containing pertechnetate is (0.8~1.2):

1.

7. The application as described in any one of claims 2 to 6, characterized in that, The extraction methods include standing or shaking.

8. The application as described in claim 7, characterized in that, When the extraction method is oscillation, the oscillation frequency is 60~120 rpm and the time is 0.5~2h.

9. The application as described in claim 8, characterized in that, After the oscillation is completed, centrifugation is also included; The centrifugation speed is 4000~12000 rpm, and the time is 3~15 min.

10. The application as described in claim 7, characterized in that, The settling time is 3 to 7 days.

Images