Magnetic nanoparticle extraction method for efficiently separating and enriching various radionuclides in aquatic products
By using magnetic nanoparticles and supercritical carbon dioxide extraction methods, the problems of low selectivity and low efficiency of uranium recovery in the prior art are solved, and efficient radionuclide separation and uranium recovery are achieved.
Patent Information
- Application Number
- CN202411831145.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-03-18
AI Technical Summary
The prior art has low selectivity, low recycling efficiency and complex operation in the uranium recycling process, resulting in low purity and low recovery rate, resulting in waste of resources.
Magnetic nanoparticles are used as adsorbents to achieve rapid separation and enrichment of radionuclides by applying magnetic fields, and the extraction method of supercritical carbon dioxide and TBP derivatives is used to improve the solubility and recovery efficiency of uranium.
Improve the separation efficiency of radionuclides and the recycling efficiency of uranium, reducing operational complexity and resource waste.
Smart Images
Figure CN119640063A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of magnetic nanoparticle extraction, in particular to a magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products. Background Art
[0002] Multiple radionuclides in enriched aquatic products refer to aquatic products (such as fish, shellfish, seaweed, etc.) absorbing multiple radionuclides from the environment during their growth. Common radionuclides include: cesium-137 (Cs-137), strontium-90 (Sr-90), iodine-131 (I-131), tritium (Tritium), lead-210 (Pb-210), uranium-238 (U-238) and uranium-235 (U-235). These nuclides accumulate in organisms and reach a certain concentration. Radionuclides include radioactive isotopes, which can emit α, β, and γ rays, causing radiation hazards to organisms and the environment.
[0003] The prior art uses universal adsorbents or ion exchange resins in the uranium recovery process. These materials have low selectivity for uranium and are prone to adsorb other ions, resulting in low uranium purity, which not only increases the difficulty of subsequent purification, but also reduces the uranium recovery efficiency. And due to the low selectivity of the adsorbent, the uranium recovery rate is also low, resulting in a waste of resources. To this end, a magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products is proposed.
[0004] The above information disclosed in this background technology is only used to increase the understanding of the background technology of the present invention and therefore, it may include information that does not constitute the prior art known to ordinary technicians in this field. Summary of the invention
[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, such as low selectivity, low recovery efficiency, and complex operation. To this end, one object of the present invention is to provide a magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products.
[0006] To achieve the above object, the present invention provides the following technical solutions:
[0007] A magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products comprises the following steps:
[0008] Step 1: Add modified chitosan to the uranium-containing water sample to form a precipitate with the uranium ions in the water, separate the precipitate by centrifugation to obtain the initially enriched uranium, dissolve the precipitate with dilute nitric acid, and adjust the pH to 3-4;
[0009] Step 2: Prepare nano-scale ion exchange resin, pass the acidified solution through a fluidized bed reactor filled with nano-ion exchange resin, the uranium ions are adsorbed by the nanoparticles, and other ions pass through the fluidized bed;
[0010] Step 3: Use supercritical carbon dioxide and add TBP derivatives to increase the solubility of uranium, mix the nano ion exchange resin with the supercritical fluid, set the temperature and pressure for extraction, release the uranium ions from the nanoparticles into the supercritical fluid, and achieve uranium separation;
[0011] Step 4: reducing the pressure of the uranium-containing supercritical fluid through a pressure reducing valve to separate the uranium ions from the supercritical fluid, collecting the uranium, and purifying the collected uranium solution using ion exchange;
[0012] Step 5: Recovering uranium from solution by chemical precipitation or electrolysis;
[0013] Step 6: Regenerate the used nano-ion exchange resin, treat the waste generated during the supercritical fluid extraction process, and recover and recycle the acid, flocculant and supercritical fluid in the process.
[0014] As a further optimization scheme of the present invention, in step 2, the method steps for preparing the nano-scale ion exchange resin are:
[0015] The surface of the nano-resin particles is modified by introducing vinyl groups. N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) are used to activate the carboxyl groups on the resin surface, which then react with the amino groups of the ligands to form covalent bonds. After the grafting is completed, the resin is thoroughly cleaned to remove unreacted ligands and by-products, and finally dried.
[0016] As a further optimization scheme of the present invention, in step 2, the feed flow rate of the fluidized bed is 0.5-1.5 L / min, the backwash flow rate is 2-4 L / min, the reaction temperature is 40-60°C, the pH value is 3-4, and the resin loading is 10-20 kg / m 3 , the bed height is 0.5-1m, and the fluidizing gas flow rate is 1-2 times the feed flow rate.
[0017] As a further optimized solution of the present invention, in step 3, the extraction temperature is 40-80° C., the extraction pressure is 10-30 MPa, the concentration of the TBP derivative is 0.5-1.5% (v / v), the nano ion exchange resin loaded with uranium ions is mixed with a mixed fluid of carbon dioxide and the TBP derivative in an extractor, the TBP derivative reacts with the uranium ions on the resin to form a complex soluble in carbon dioxide, thereby releasing the uranium ions from the resin into the supercritical fluid, the extraction time is 10-30 minutes, so that the uranium ions are transferred to the supercritical fluid phase, and after the extraction is completed, the uranium-containing carbon dioxide fluid is decompressed through a pressure reducing valve to convert it from a supercritical state to a gaseous state or a liquid state, thereby achieving separation of uranium ions and carbon dioxide.
[0018] As a further optimization scheme of the present invention, in step 4, the ion exchange resin is loaded into the column, a solution containing uranium is prepared, and the solution containing uranium is slowly pumped into the ion exchange column at a solution flow rate of 0.5-2.5 mL / min. The uranium ions undergo ion exchange reactions with functional groups on the ion exchange resin and are adsorbed by the resin, while other ions in the solution flow out through the column. The uranium ions adsorbed on the resin are eluted using dilute nitric acid, the eluate is collected, and the resin is washed with hydrochloric acid to remove the adsorbed uranium ions and other impurities. After washing, the resin is rinsed with deionized water to remove residual regeneration agent and eluted impurities.
[0019] As a further optimization scheme of the present invention, in step six, the method steps for regenerating the nano ion exchange resin are as follows:
[0020] Confirm that the resin is saturated, use 0.5-2M hydrochloric acid solution, remove the saturated resin from the ion exchange column, transfer it to a cleaning container, add the hydrochloric acid solution to the resin, and stir to promote the elution of uranium ions. The addition rate of the hydrochloric acid solution is 0.5-2mL / min.
[0021] The hydrochloric acid reacts with the uranium ions on the resin to form uranium chloride. The elution time is 10-30 minutes. The eluate is collected, the uranium ions are recovered and the harmful substances are removed. The resin is washed several times with deionized water. After the washing and regeneration process is completed, the resin is placed back into the ion exchange column to prepare for the second adsorption.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] The present invention uses magnetic nanoparticles as adsorbents to achieve rapid separation and enrichment of radioactive nuclides through an external magnetic field, thereby improving separation efficiency. The solubility of uranium in supercritical carbon dioxide is increased by adding TBP derivatives, which helps release uranium from nano ion exchange resins and improves uranium recovery efficiency.
[0024] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 The figure is a flowchart of the magnetic nanoparticle extraction method of the present invention. DETAILED DESCRIPTION
[0026] 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.
[0027] Embodiment 1
[0028] See also Figure 1 , a magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products, comprising the following steps:
[0029] Selection and preparation of modified chitosan: Chitosan is used as a substrate and hydroxyl groups are introduced into the chitosan molecules through chemical reactions.
[0030] Batch experiments of modified chitosan:
[0031] Modified chitosan solutions of different concentrations were added to water samples containing known concentrations of uranium ions. The amount of modified chitosan added was increased successively to 5 mg / L, 10 mg / L, 15 mg / L, 20 mg / L, and 25 mg / L, and the precipitation efficiency of uranium ions was observed. At the same time, the reaction time was increased successively to 10 min, 20 min, 30 min, and 1 h for sampling.
[0032] Add the modified chitosan solution to the uranium-containing water sample and stir evenly to allow the uranium ions to fully contact the modified chitosan and form a precipitate. Centrifuge at 3000 speed for 15 minutes and then collect the precipitate. Dissolve the collected precipitate with dilute nitric acid to release the uranium ions. Adjust the pH value of the solution to 3-4.
[0033] Add modified chitosan to the uranium-containing water sample to form a precipitate with the uranium ions in the water. Separate the precipitate by centrifugation to obtain the initially enriched uranium. Dissolve the precipitate with dilute nitric acid and adjust the pH to 3-4.
[0034] The method steps for preparing nano-scale ion exchange resin are:
[0035] The surface of the nano-resin particles is modified by introducing vinyl groups. N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) are used to activate the carboxyl groups on the resin surface, which then react with the amino groups of the ligands to form covalent bonds. After the grafting is completed, the resin is thoroughly cleaned to remove unreacted ligands and by-products, and finally dried.
[0036] The feed flow rate of the fluidized bed is 0.5-1.5L / min, the backwash flow rate is 2-4L / min, the reaction temperature is 40-60℃, the pH value is 3-4, and the resin loading is 10-20kg / m 3 , the bed height is 0.5-1m, and the fluidizing gas flow rate is 1-2 times the feed flow rate.
[0037] The acidified solution is passed through a fluidized bed reactor filled with nano-ion exchange resin, where the uranium ions are adsorbed by the nanoparticles while other ions pass through the fluidized bed;
[0038] Using supercritical carbon dioxide and adding TBP derivatives to increase the solubility of uranium, nano-ion exchange resin is mixed with supercritical fluid, and the temperature and pressure are set for extraction. Uranium ions are released from nanoparticles into the supercritical fluid to achieve uranium separation;
[0039] Specifically, the method steps for verifying the coordination ability of TBP derivatives with uranium are as follows:
[0040] The experimental temperature was set at 40-80 °C, which was divided into five temperature gradients, namely 40 °C, 50 °C, 60 °C, 70 °C and 80 °C.
[0041] The experimental pressure was set at 10-30 MPa, which was divided into five pressure gradients, namely 10 MPa, 15 MPa, 20 MPa, 25 MPa and 30 MPa.
[0042] Different concentrations of TBP derivative solutions were used in the experiment, and the concentration gradient was set to 0.1%, 0.5%, 1.0%, 1.5% and 2.0% (v / v).
[0043] Prepare the synthesized and purified TBP derivatives, perform at least three repeated experiments at each temperature and pressure condition, adjust the concentration of TBP derivatives, perform at least three repeated experiments, mix the nano-ion exchange resin loaded with uranium ions with the TBP derivatives, place the mixture in an extractor according to the set temperature and pressure, measure and record the amount of uranium ions released during the experiment, and evaluate the coordination ability of TBP derivatives with uranium.
[0044] Specifically, the experimental materials include synthesized and purified TBP derivatives, uranium-containing water samples, supercritical carbon dioxide fluid, nano-ion exchange resin, high-pressure extractor, flow meter, pressure gauge, thermometer, and collection container.
[0045] Experimental procedures: The concentration gradient of TBP derivatives was set to 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% (v / v), and each concentration gradient was repeated at least three times.
[0046] The nano-ion exchange resin loaded with uranium ions was mixed with supercritical carbon dioxide and extracted at a set temperature and pressure. In each experiment, different concentrations of TBP derivative solution were added to the supercritical carbon dioxide, and the temperature and pressure of the extraction process were kept constant. The extraction time at each concentration was recorded. After the extraction was completed, the supercritical carbon dioxide fluid containing uranium was collected and separated by a pressure reducing valve. The amount of uranium extracted in each experiment was measured and recorded.
[0047] The uranium extraction efficiency under different TBP derivative concentrations was compared, and the relationship between TBP derivative concentration and uranium extraction efficiency was plotted to determine the TBP derivative concentration that achieved the highest extraction efficiency. Based on the experimental results, the TBP derivative concentration with the highest extraction efficiency was selected as the optimal concentration.
[0048] The extraction temperature is 40-80°C, the extraction pressure is 10-30MPa, the concentration of the TBP derivative is 0.5-1.5% (v / v), the nano ion exchange resin loaded with uranium ions is mixed with a mixed fluid of carbon dioxide and the TBP derivative in an extractor, the TBP derivative reacts with the uranium ions on the resin to form a complex soluble in carbon dioxide, the uranium ions are released from the resin into the supercritical fluid, the extraction time is 10-30min, the uranium ions are transferred to the supercritical fluid phase, after the extraction is completed, the uranium-containing carbon dioxide fluid is decompressed through a pressure reducing valve, so that it is converted from a supercritical state to a gaseous state or a liquid state, and the uranium ions and the carbon dioxide are separated.
[0049] The uranium-containing supercritical fluid is depressurized through a pressure reducing valve to separate uranium ions from the supercritical fluid, and the uranium is collected, and the collected uranium solution is purified by ion exchange;
[0050] Specifically, the ion exchange resin is loaded into the column, a uranium-containing solution is prepared, and the uranium-containing solution is slowly pumped into the ion exchange column at a solution flow rate of 0.5-2.5 mL / min. The uranium ions undergo ion exchange reactions with functional groups on the ion exchange resin and are adsorbed by the resin, while other ions in the solution flow out through the column. The uranium ions adsorbed on the resin are eluted with dilute nitric acid, and the eluate is collected. The resin is cleaned with hydrochloric acid to remove the adsorbed uranium ions and other impurities. After cleaning, the resin is rinsed with deionized water to remove residual regeneration agent and eluted impurities.
[0051] The steps for recovering uranium from solution by chemical precipitation are:
[0052] Sodium hydroxide and sodium carbonate are used as precipitants, and the precipitant solution is added to the uranium solution and stirred. The rate of the precipitant is 0.5-2mL / min. The precipitant reacts with the uranium ion to generate an insoluble precipitate. After the precipitation reaction is completed, the precipitate is separated from the solution by centrifugation so that the precipitate is completely separated. The precipitate is washed to remove adsorbed impurities and unreacted precipitant, and the washed precipitate is dried.
[0053] Regenerate used nano-ion exchange resins, treat waste generated during supercritical fluid extraction, and recover and recycle acids, flocculants and supercritical fluids in the process.
[0054] Specifically, the method steps for regenerating the nano ion exchange resin are as follows:
[0055] Confirm that the resin is saturated, use 0.5-2M hydrochloric acid solution, remove the saturated resin from the ion exchange column, transfer it to a cleaning container, add the hydrochloric acid solution to the resin, and stir to promote the elution of uranium ions. The addition rate of the hydrochloric acid solution is 0.5-2mL / min.
[0056] The hydrochloric acid reacts with the uranium ions on the resin to form uranium chloride. The elution time is 10-30 minutes. The eluate is collected, the uranium ions are recovered and the harmful substances are removed. The uranium ions are recovered from the eluate by solvent extraction. The types of harmful substances in the eluate are analyzed and removed by evaporation and concentration. The resin is washed with deionized water for multiple times. After the washing and regeneration process is completed, the resin is placed back into the ion exchange column to prepare for the second adsorption.
[0057] Embodiment 2
[0058] The steps for recovering uranium from solution by electrolysis are:
[0059] Configure an electrolytic cell, use nitric acid as the electrolyte, platinum and titanium as the electrode materials, use a solution containing uranium as the electrolyte, the solution temperature is 25-50°C, and the current density is 0.1-0.5A / cm 2 , the voltage is 2-5 volts, the electrolysis time is 30-120 minutes, the electrolytic cell is turned on, and the current is passed through the solution. At the cathode, the uranium ions are reduced to metallic uranium and deposited on the cathode; at the anode, an oxidation reaction occurs to generate oxides. After the electrolysis is completed, the electrolytic cell is closed, the uranium metal is collected from the cathode, and it is cleaned and dried to remove the oxides and impurities formed during the electrolysis process.
[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention.
[0061] Parts not involved in the present invention are the same as the prior art or can be implemented by the prior art. Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products, characterized in that: The steps include: Step 1: Add modified chitosan to the uranium-containing water sample to form a precipitate with the uranium ions in the water, separate the precipitate by centrifugation to obtain the initially enriched uranium, dissolve the precipitate with dilute nitric acid, and adjust the pH to 3-4; Step 2: Prepare nano-scale ion exchange resin, pass the acidified solution through a fluidized bed reactor filled with nano-ion exchange resin, the uranium ions are adsorbed by the nanoparticles, and other ions pass through the fluidized bed; Step 3: Use supercritical carbon dioxide and add TBP derivatives to increase the solubility of uranium, mix the nano ion exchange resin with the supercritical fluid, set the temperature and pressure for extraction, release the uranium ions from the nanoparticles into the supercritical fluid, and achieve uranium separation; Step 4: reducing the pressure of the uranium-containing supercritical fluid through a pressure reducing valve to separate the uranium ions from the supercritical fluid, collecting the uranium, and purifying the collected uranium solution using ion exchange; Step 5: Recovering uranium from solution by chemical precipitation or electrolysis; Step 6: Regenerate the used nano-ion exchange resin, treat the waste generated during the supercritical fluid extraction process, and recover and recycle the acid, flocculant and supercritical fluid in the process.
2. The method for extracting a plurality of radionuclides from aquatic products using magnetic nanoparticles for efficient separation and enrichment according to claim 1, characterized in that: In step 2, the method steps for preparing nano-scale ion exchange resin are: The surface of the nano-resin particles is modified by introducing vinyl groups. N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) are used to activate the carboxyl groups on the resin surface, which then react with the amino groups of the ligands to form covalent bonds. After the grafting is completed, the resin is thoroughly cleaned to remove unreacted ligands and by-products, and finally dried.
3. The magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products according to claim 1 is characterized in that: In step 2, the feed flow rate of the fluidized bed is 0.5-1.5 L / min, the backwash flow rate is 2-4 L / min, the reaction temperature is 40-60°C, the pH value is 3-4, and the resin loading is 10-20 kg / m 3 , the bed height is 0.5-1m, and the fluidizing gas flow rate is 1-2 times the feed flow rate.
4. The method for extracting a plurality of radionuclides from aquatic products using magnetic nanoparticles for efficient separation and enrichment according to claim 1, characterized in that: In step three, the extraction temperature is 40-80° C., the extraction pressure is 10-30 MPa, the concentration of the TBP derivative is 0.5-1.5% (v / v), the nano ion exchange resin loaded with uranium ions is mixed with a mixed fluid of carbon dioxide and the TBP derivative in an extractor, the TBP derivative reacts with the uranium ions on the resin to form a complex soluble in carbon dioxide, so that the uranium ions are released from the resin into the supercritical fluid, the extraction time is 10-30 minutes, so that the uranium ions are transferred to the supercritical fluid phase, and after the extraction is completed, the uranium-containing carbon dioxide fluid is decompressed through a pressure reducing valve to convert it from a supercritical state to a gaseous state or a liquid state, thereby achieving separation of uranium ions and carbon dioxide.
5. The magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products according to claim 1, characterized in that: In step 4, the ion exchange resin is loaded into the column, and a solution containing uranium is prepared. The solution containing uranium is slowly pumped into the ion exchange column at a solution flow rate of 0.5-2.5 mL / min. The uranium ions undergo ion exchange reactions with functional groups on the ion exchange resin and are adsorbed by the resin. Other ions in the solution flow out through the column. The uranium ions adsorbed on the resin are eluted with dilute nitric acid, and the eluate is collected. The resin is washed with hydrochloric acid to remove the adsorbed uranium ions and other impurities. After washing, the resin is rinsed with deionized water to remove residual regeneration agent and eluted impurities.
6. The magnetic nanoparticle extraction method for efficiently separating and enriching multiple radionuclides in aquatic products according to claim 1, characterized in that: In step six, the method steps for regenerating the nano ion exchange resin are as follows: Confirm that the resin is saturated, use 0.5-2M hydrochloric acid solution, remove the saturated resin from the ion exchange column, transfer it to a cleaning container, add the hydrochloric acid solution to the resin, and stir to promote the elution of uranium ions. The rate of adding the hydrochloric acid solution is 0.5-2mL / min; The hydrochloric acid reacts with the uranium ions on the resin to form uranium chloride. The elution time is 10-30 minutes. The eluate is collected, the uranium ions are recovered and the harmful substances are removed. The resin is washed several times with deionized water. After the washing and regeneration process is completed, the resin is placed back into the ion exchange column to prepare for the second adsorption.