A carbonate eluent, its preparation method and application

Abstract

The present invention relates to a carbonate eluent and its preparation method and application, belonging to the technical field of radioactive nuclide contaminated soil remediation and treatment. The carbonate eluent provided by the present invention comprises carbonate, bicarbonate, an oxidant, a deep eutectic solvent and an anionic surfactant; the oxidant comprises sodium chlorite and hydrogen peroxide; the deep eutectic solvent comprises choline chloride and urea; the molar ratio of carbonate, bicarbonate and hydrogen peroxide is (0.005-0.025):(0.025-0.1):(0.3-0.5); the molar ratio of choline chloride and urea in the deep eutectic solvent is (0.8-1.2):(0.8-1.2). The eluent prepared by the present invention is green and mild, and significantly improves the removal rate of uranium in soil by regulating appropriate component ratios, which is of great significance to the safe development of the nuclear power industry and the protection and treatment of radioactive polluted environment.

Description

Technical Field

[0001] The present invention relates to the technical field of radioactive nuclide contaminated soil remediation and treatment, and particularly relates to a carbonate eluent and its preparation method and application. Background Art

[0002] With the increasing frequency of processing and use of radioactive elements, the pollution problem caused by uranium-containing minerals to the environment is becoming more and more serious. Due to insufficient protection in the uranium mining and metallurgy industry, some uranium-containing mineral powders settle into the surrounding soil environment during transportation and production, causing varying degrees of soil uranium pollution. Uranium not only has radioactive damage to organisms, but also has heavy metal chemical toxicity. It is absorbed by plants and animals in the environment and enters the ecosystem along the food chain, which may affect the growth and development of organisms and cause damage to genetic materials.

[0003] At present, due to the increasingly prominent problem of soil uranium pollution in some decommissioned uranium mine fields, it is very urgent and necessary to carry out research on the remediation and treatment technologies of radioactive nuclide uranium contaminated soil, which is of great significance for the ecological environment governance and protection of uranium mines in China. Chemical leaching technology has been widely studied due to its advantages such as simple operation, wide application range, and engineering applicability. However, the existing technology uses strong acids and strong alkalis as eluents, which have a greater impact on the composition and structure of the soil and are not conducive to the ecological restoration of the soil environment.

[0004] Therefore, actively researching and developing new uranium contaminated soil eluents that are green, mild, highly efficient, clean, and do not damage the soil composition and structure is of great significance for the safe development of the nuclear power industry and the protection and remediation of radioactive polluted environments. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a carbonate eluent and its preparation method and application. The carbonate eluent provided by the present invention has a high removal rate of uranium in the soil, is mild and environmentally friendly, and does not damage the soil structure and restore its use function.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention provides a carbonate eluent, which comprises the following components: carbonate, bicarbonate, oxidant, deep eutectic solvent, anionic surfactant; the oxidant comprises sodium chlorite and hydrogen peroxide; the deep eutectic solvent comprises choline chloride and urea; the molar ratio of carbonate, bicarbonate and hydrogen peroxide is carbonate: bicarbonate: hydrogen peroxide = (0.05 - 0.25): (0.25 - 1): (3 - 5); the molar ratio of choline chloride and urea in the deep eutectic solvent is (0.8 - 1.2): (0.8 - 1.2).

[0008] The present invention uses a combination of carbonate, bicarbonate and oxidant for leaching to remove uranium from soil: As a relatively mild leaching agent, carbonate can better protect the soil structure during the leaching process. The uranyl ion can form a soluble complex with carbonate in the system and be removed from soil particles. The addition of hydrogen peroxide promotes the oxidation of insoluble tetravalent uranium in the soil to soluble hexavalent uranium, which is then leached out of the soil. Moreover, compared with oxidants such as potassium permanganate and potassium dichromate, the use of hydrogen peroxide can avoid secondary pollution of the soil while ensuring the oxidation effect.

[0009] The specific ratio of carbonate, bicarbonate and oxidant in the present invention can significantly improve the dissolution and removal effect of the leaching agent on uranium in soil. When the ratio of the three is outside this range, it may lead to a significant decrease in the removal rate of uranium in soil when using the leaching agent.

[0010] The present invention also uses a deep eutectic solvent composed of choline chloride and urea. As a strong electron donor, it is extremely easy to coordinate with uranyl ions, reducing the frequency of uranium that has entered the solution from being re-adsorbed onto the soil surface. At the same time, the addition of an anionic surfactant reduces the surface tension of soil particles, promotes soil dissociation and the dissolution of uranyl ions, and further improves the removal efficiency. The above specific deep eutectic solvent system and ratio can significantly improve the removal rate of uranium in soil by the leaching agent and significantly improve the soil remediation effect of the leaching agent; changing the system ratio may lead to a significant deterioration in the removal effect of uranium.

[0011] The above leaching agent system provided by the present invention has green and mild components and a buffer system, which can reduce the damage to the soil structure during the leaching process and is more conducive to restoring the use function of the soil; and when the initial concentration of uranium in the soil is 735.17 mg / kg, the removal rate of uranium in the soil can reach more than 85%, showing extremely high application potential in the restoration of severely uranium-polluted soil.

[0012] Preferably, the molar ratio of sodium chlorite to hydrogen peroxide is 0.3:(3 - 5).

[0013] More preferably, the molar ratio of carbonate, bicarbonate and hydrogen peroxide is carbonate:bicarbonate:hydrogen peroxide = 0.1:0.5:4.

[0014] Preferably, the molar ratio of choline chloride to urea is 1:1.

[0015] The carbonate leaching agent system under the above component ratio can achieve the optimal removal effect of uranium in soil, and the removal rate of uranium in the soil can reach more than 93%.

[0016] Preferably, the carbonate is potassium carbonate and the bicarbonate is potassium bicarbonate.

[0017] A leaching system using potassium carbonate and potassium bicarbonate, in which the presence of potassium ions can promote the migration of uranyl ions inside soil particles and better dissolve uranium in the soil.

[0018] Further preferably, the mass ratio of the potassium carbonate to the deep eutectic solvent is (0.691 - 3.456):(2 - 6). As a preferred embodiment, the mass ratio of the potassium carbonate to the deep eutectic solvent is (0.691 - 3.456):4.

[0019] Preferably, the anionic surfactant includes sodium dodecylbenzenesulfonate and sodium dodecyl sulfate.

[0020] Further preferably, the molar ratio of the carbonate, sodium dodecylbenzenesulfonate and sodium dodecyl sulfate is carbonate:sodium dodecylbenzenesulfonate:sodium dodecyl sulfate = (5 - 25):(0.44 - 0.47):(0.47 - 0.50).

[0021] The combined action of the deep eutectic solvent and the anionic surfactant within the above dosage ranges can significantly improve the removal effect of the carbonate leaching agent of the present invention on uranium in the soil.

[0022] In a second aspect, the present invention provides a preparation method of the above carbonate leaching agent, including the following steps:

[0023] (1) Dissolve the carbonate and bicarbonate in water, and then add an oxidant and mix evenly to obtain solution A;

[0024] (2) Add the deep eutectic solvent and the anionic surfactant to solution A and dissolve and mix evenly to obtain the carbonate leaching agent.

[0025] Preferably, the preparation method of the deep eutectic solvent is as follows: Melt and mix choline chloride and urea in a boiling water bath, and then cool and dry to obtain the deep eutectic solvent.

[0026] Preferably, the way of dissolving and mixing evenly includes ultrasonic and stirring; the rotation speed of the stirring is 200 - 800 r / min.

[0027] In a third aspect, the present invention provides an application of the above carbonate leaching agent in the remediation of uranium - contaminated soil.

[0028] As a preferred embodiment, the application includes the following steps:

[0029] Add the leaching agent to the uranium - contaminated soil after grinding and screening, and the addition ratio of the soil to the leaching agent is 1 t:1 - 3 m 3 ; Conduct leaching treatment at room temperature, and then mix, stir, and separate the mud and water to complete the remediation of the uranium - contaminated soil.

[0030] When the carbonate eluent provided by the present invention is used and the concentration of potassium carbonate is about 0.005 - 0.025 moL / L, the highest uranium removal rate can be achieved after about 8 hours of elution treatment.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] Based on the concept of the chemical elution technology for contaminated soil in existing research, the present invention innovates by screening the ratios of carbonate, oxidant, solubilizer, etc. to obtain a carbonate eluent. This preparation avoids the damage to the soil structure caused by the use of strong acids and strong bases (such as nitric acid, sodium hydroxide, etc.), and can effectively remove uranium in the soil. The maximum uranium removal rate of this carbonate agent for contaminated soil reaches 93.02%. Description of the Drawings

[0033] Figure 1 Schematic diagram of the carbonate eluent prepared in Example 1;

[0034] Figure 2 Restoration effect diagrams of the eluents in Examples 1 - 5 (a - e) and Comparative Examples 1 - 7 (f) on uranium - contaminated soil. Detailed Embodiments

[0035] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The test methods used in the following embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0036] Example 1

[0037] An embodiment of the carbonate eluent of the present invention. The preparation method of the carbonate eluent in this embodiment is as follows:

[0038] (1) Disperse 0.005 mol of potassium carbonate and 0.025 mol of potassium bicarbonate into 900 mL of deionized water, ultrasonic for 30 min and then stir for 1 h; continue to add 0.03 mol of sodium chlorite under the condition of magnetic stirring at 500 r / min to completely dissolve all solid particles, and then slowly add hydrogen peroxide solution until the hydrogen peroxide is 0.3 mol to obtain a mixed solution A;

[0039] (2) Mix 1 mol of choline chloride and 1 mol of urea, stir and heat in a boiling water bath for 1 h until all solid substances are dissolved. After the solution is cooled to room temperature, place it in a vacuum drying oven and dry for 12 h to obtain a viscous liquid eutectic solvent;

[0040] (3) Add 4 g of the eutectic solvent to the mixed solution A. After dispersing evenly, add 0.16 g of sodium dodecylbenzenesulfonate and 0.14 g of sodium dodecyl sulfate, and continue stirring until all solid particles are completely dissolved to obtain the carbonate eluent, as Figure 1 shown.

[0041] Example 2

[0042] An example of the carbonate eluent of the present invention. The preparation method of the carbonate eluent in this example is as follows:

[0043] (1) Disperse 0.01 mol of potassium carbonate and 0.05 mol of potassium bicarbonate in 900 mL of deionized water. After ultrasonic treatment for 30 min and stirring for 1 h, continue to add 0.03 mol of sodium chlorite under the condition of magnetic stirring at 500 r / min to completely dissolve all solid particles, and then slowly add hydrogen peroxide solution until the hydrogen peroxide is 0.4 mol to obtain mixed solution A;

[0044] (2) Mix 1 mol of choline chloride and 1 mol of urea, stir and heat in a boiling water bath for 1 h until all solids are dissolved. After the solution is cooled to room temperature, place it in a vacuum drying oven and dry for 12 h to obtain a viscous liquid eutectic solvent;

[0045] (3) Add 4 g of the eutectic solvent to the mixed solution A. After dispersing evenly, add 0.16 g of sodium dodecylbenzenesulfonate and 0.14 g of sodium dodecyl sulfate, and continue stirring until all solid particles are completely dissolved to obtain the carbonate eluent.

[0046] Example 3

[0047] An example of the carbonate eluent of the present invention. The preparation method of the carbonate eluent in this example is as follows:

[0048] (1) Disperse 0.025 mol of potassium carbonate and 0.1 mol of potassium bicarbonate in 900 mL of deionized water. After ultrasonic treatment for 30 min and stirring for 1 h, continue to add 0.03 mol of sodium chlorite under the condition of magnetic stirring at 500 r / min to completely dissolve all solid particles, and then slowly add hydrogen peroxide solution until the hydrogen peroxide is 0.5 mol to obtain mixed solution A;

[0049] (2) Mix 1 mol of choline chloride and 1 mol of urea, stir and heat in a boiling water bath for 1 h until all solids are dissolved. After the solution is cooled to room temperature, place it in a vacuum drying oven and dry for 12 h to obtain a viscous liquid eutectic solvent;

[0050] (3) Add 4 g of the eutectic solvent to the mixed solution A. After dispersing evenly, add 0.16 g of sodium dodecylbenzenesulfonate and 0.14 g of sodium dodecyl sulfate, and continue stirring until all solid particles are completely dissolved to obtain the carbonate eluent.

[0051] Example 4

[0052] An example of the carbonate eluent of the present invention. The difference between the preparation method of the carbonate eluent in this example and that in Example 2 is only that in step (2), 0.8 mol of choline chloride and 1.2 mol of urea are used to prepare the eutectic solvent.

[0053] Example 5

[0054] An example of the carbonate eluent of the present invention. The difference between the preparation method of the carbonate eluent in this example and that in Example 2 is only that in step (2), 1.2 mol of choline chloride and 0.8 mol of urea are used to prepare the eutectic solvent.

[0055] Comparative Example 1

[0056] An eluent is prepared by the following method:

[0057] (1) Disperse 0.003 mol of potassium carbonate and 0.02 mol of potassium bicarbonate in 900 mL of deionized water. After ultrasonic treatment for 30 min and stirring for 1 h, continue to add 0.03 mol of sodium chlorite under the condition of magnetic stirring at 500 r / min to completely dissolve all solid particles, and then slowly add hydrogen peroxide solution until the hydrogen peroxide is 0.5 mol to obtain the mixed solution A;

[0058] (2) Mix 1 mol of choline chloride and 1 mol of urea, and stir and heat in a boiling water bath for 1 h until all solids are dissolved. After the solution is cooled to room temperature, place it in a vacuum drying oven and dry for 12 h to obtain a viscous liquid eutectic solvent;

[0059] (3) Add 4 g of the eutectic solvent to the mixed solution A. After dispersing evenly, add 0.16 g of sodium dodecylbenzenesulfonate and 0.14 g of sodium dodecyl sulfate, and continue stirring until all solid particles are completely dissolved to obtain the eluent.

[0060] Comparative Example 2

[0061] An eluent is prepared by the following method:

[0062] (1) Disperse 0.06 mol of potassium carbonate and 0.1 mol of potassium bicarbonate in 900 mL of deionized water. After ultrasonic treatment for 30 min and stirring for 1 h, continue to add 0.03 mol of sodium chlorite under the condition of magnetic stirring at 500 r / min to completely dissolve all solid particles. Then, slowly add hydrogen peroxide solution until the amount of hydrogen peroxide reaches 0.2 mol to obtain a mixed solution A;

[0063] (2) Mix 1 mol of choline chloride and 1 mol of urea, stir and heat in a boiling water bath for 1 h until all solid substances are dissolved. After the solution cools to room temperature, place it in a vacuum drying oven and dry for 12 h to obtain a viscous liquid deep eutectic solvent;

[0064] (3) Add 4 g of the deep eutectic solvent to the mixed solution A. After dispersing evenly, add 0.16 g of sodium dodecylbenzenesulfonate and 0.14 g of sodium dodecyl sulfate, and continue to stir until all solid particles are completely dissolved to obtain an eluent.

[0065] Comparative Example 3

[0066] An eluent is prepared by the following method:

[0067] (1) Disperse 0.01 mol of potassium carbonate and 0.05 mol of potassium bicarbonate in 900 mL of deionized water. After ultrasonic treatment for 30 min and stirring for 1 h, obtain a mixed solution A;

[0068] (2) Mix 1 mol of choline chloride and 1 mol of urea, stir and heat in a boiling water bath for 1 h until all solid substances are dissolved. After the solution cools to room temperature, place it in a vacuum drying oven and dry for 12 h to obtain a viscous liquid deep eutectic solvent;

[0069] (3) Add 4 g of the deep eutectic solvent to the mixed solution A. After dispersing evenly, add 0.16 g of sodium dodecylbenzenesulfonate and 0.14 g of sodium dodecyl sulfate, and continue to stir until all solid particles are completely dissolved to obtain an eluent.

[0070] Comparative Example 4

[0071] An eluent is prepared by the following method:

[0072] Disperse 0.01 mol of potassium carbonate and 0.05 mol of potassium bicarbonate in 900 mL of deionized water. After ultrasonic treatment for 30 min and stirring for 1 h, continue to add 0.03 mol of sodium chlorite under the condition of magnetic stirring at 500 r / min to completely dissolve all solid particles. Then, slowly add hydrogen peroxide solution until the amount of hydrogen peroxide reaches 0.4 mol to obtain an eluent.

[0073] Comparative Example 5

[0074] The difference between Comparative Example 5 and Example 3 is only that in step (2), a deep eutectic solvent is prepared using 1 mol of choline chloride and 1.8 mol of urea.

[0075] Comparative Example 6

[0076] The difference between Comparative Example 6 and Example 3 is only that in step (2), a deep eutectic solvent is prepared using 1.8 mol of choline chloride and 1 mol of urea.

[0077] Comparative Example 7

[0078] An eluent is prepared by the following method:

[0079] (1) 0.01 mol of potassium carbonate and 0.05 mol of potassium bicarbonate are dispersed in 900 mL of deionized water, ultrasonicated for 30 min and then stirred for 1 h; under the condition of magnetic stirring at 500 r / min, 0.03 mol of sodium chlorite is continuously added to completely dissolve all solid particles, and hydrogen peroxide solution is continuously added slowly until the hydrogen peroxide is 0.4 mol to obtain a mixed solution A;

[0080] (2) 1 mol of choline chloride and 1 mol of ethylene glycol are mixed, and then stirred and heated in a boiling water bath for 1 h until all solids are dissolved. After the solution is cooled to room temperature, it is placed in a vacuum drying oven and dried for 12 h to obtain a viscous liquid deep eutectic solvent;

[0081] (3) 4 g of the deep eutectic solvent is added to the mixed solution A, and after being dispersed evenly, 0.16 g of sodium dodecylbenzenesulfonate and 0.14 g of sodium dodecyl sulfate are added, and stirring is continued until all solid particles are completely dissolved to obtain the eluent.

[0082] Effect Example

[0083] To explore the remediation effect of the carbonate eluent provided by the present invention on severely uranium-contaminated soil, the eluents in the examples and comparative examples were used for the leaching remediation of severely uranium-contaminated soil, and the specific test steps are as follows:

[0084] The eluent is added to the uranium-contaminated soil after grinding and sieving. The initial concentration of uranium in the soil is 735.17 mg / kg, and the ratio of soil to eluent is 1 t: 2 m 3 ; The leaching treatment is carried out at room temperature, and then mixed, stirred, and separated from mud and water to complete the soil remediation;

[0085] Samples are taken at different times within 24 h of treatment to measure the concentration of uranium in the soil, and the uranium removal rate is calculated. The results are as Figure 2 . Among them Figure 2 -(a)-(e) are the uranium removal rates of the carbonate eluents in Examples 1-5 for the contaminated soil at different leaching times; Figure 2-(f) is a comparison of the uranium removal rates of the eluents in Comparative Examples 1-7 at different elution times with that of Example 2.

[0086] It can be seen from Figure 2 that:

[0087] (1) After eluting the soil with the eluents of each example and comparative example for 8 h, the uranium removal rate in the soil reaches the highest point. The carbonate eluents in the examples have significantly better remediation effects on uranium-contaminated soil than the eluents in the comparative examples. Among them, the scheme adopted in Example 2 has the best effect.

[0088] The highest uranium removal rate of the carbonate eluent in Example 1 can reach 86.71%, and then the removal rate fluctuates around 85%; the highest uranium removal rate of the carbonate eluent in Example 2 can reach 93.02%, and then the removal rate fluctuates around 92%; the highest uranium removal rate of the carbonate eluent in Example 3 can reach 89.42%, and then the removal rate fluctuates around 87%; the highest uranium removal rate of the carbonate eluent in Example 4 can reach 90.11%, and then the removal rate fluctuates around 89%; the highest uranium removal rate of the carbonate eluent in Example 5 can reach 91.26%, and then the removal rate fluctuates around 90%.

[0089] (2) Compared with the examples, the eluents in Comparative Example 1, Comparative Example 2 and Comparative Example 3 respectively adjust the dosage ratios of potassium carbonate / potassium bicarbonate, potassium carbonate / hydrogen peroxide, and do not add an oxidant, which fall outside the scope defined by the present invention. Under the same treatment conditions, the highest uranium removal rate in Comparative Example 1 reaches 64.67%, and then the removal rate fluctuates around 61%; the highest uranium removal rate in Comparative Example 2 reaches 71.72%, and then the removal rate fluctuates around 68%; the highest uranium removal rate in Comparative Example 3 is only 43.19%, and then the removal rate fluctuates around 40%; all are significantly lower than the data of the examples. It can be seen that at the specific dosage ratio of potassium carbonate / potassium bicarbonate / oxidant of the present invention, the migration of uranyl ions inside soil particles can be accelerated, and the insoluble tetravalent uranium in the soil can be better oxidized to soluble hexavalent uranium and dissolved out from the soil, significantly improving the uranium removal effect of the eluent on the soil.

[0090] (4) Compared with the examples, Comparative Examples 4-7 changed the use conditions of the deep eutectic solvent in the eluent: under the same soil treatment conditions, in Comparative Example 4, the eluent did not add the deep eutectic solvent and anionic surfactant, and the highest uranium removal rate reached 66.51%, and then the removal rate fluctuated around 63%; in Comparative Example 5, the dosage ratio was adjusted, and the dosage of choline chloride was too high, and the highest uranium removal rate from the soil reached 74.15%, and then the removal rate fluctuated around 70%; in Comparative Example 6, the dosage ratio was adjusted, and the dosage of urea was too high, and the highest uranium removal rate from the soil reached 78.49%, and then the removal rate fluctuated around 75%; in Comparative Example 7, the choline chloride / urea system was replaced with choline chloride / ethylene glycol, and the highest uranium removal rate from the soil reached 69.83%, and then the removal rate fluctuated around 65%. It can be seen that the deep eutectic solvent system and its ratio defined in the present invention are more conducive to coordinating with uranyl ions, reducing the re-adsorption of the dissolved uranium back to the soil surface, and significantly improving the remediation effect of the eluent on uranium-contaminated soil.

[0091] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A carbonate eluent, characterized in that: The invention comprises the following components: potassium carbonate, potassium bicarbonate, an oxidant, a low eutectic solvent, and an anionic surfactant; the oxidant comprises sodium chlorite and hydrogen peroxide; the low eutectic solvent comprises choline chloride and urea; the molar ratio of potassium carbonate, potassium bicarbonate and hydrogen peroxide is potassium carbonate:potassium bicarbonate:hydrogen peroxide=(0.05-0.25):(0.25-1):(3-5); the molar ratio of choline chloride and urea in the low eutectic solvent is (0.8-1.2):(0.8-1.2); the mass ratio of potassium carbonate to the low eutectic solvent is (0.691-3.456):(2-6).

2. The carbonate eluent according to claim 1, characterized in that The molar ratio of sodium chlorite to hydrogen peroxide is 0.3:(3-5).

3. The carbonate eluent according to claim 1, characterized in that The molar ratio of the choline chloride to the urea is 1:

1.

4. The carbonate eluent according to claim 1, characterized in that The anionic surfactants include sodium dodecylbenzene sulfonate and sodium dodecyl sulfate.

5. The carbonate eluent according to claim 4, characterized in that The molar ratio of potassium carbonate, sodium dodecylbenzene sulfonate and sodium dodecyl sulfate is potassium carbonate: sodium dodecylbenzene sulfonate: sodium dodecyl sulfate = (5-25): (0.44-0.47): (0.47-0.50).

6. The method for preparing the carbonate eluent according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) dissolving potassium carbonate and potassium bicarbonate in water, then adding an oxidant and mixing well to obtain a solution A; (2) adding a low eutectic solvent and an anionic surfactant into the solution A to dissolve and mix well, thereby obtaining the carbonate eluent.

7. The method for preparing the carbonate eluent according to claim 6, characterized in that: The preparation method of the low eutectic solvent is as follows: choline chloride and urea are melted and mixed in a boiling water bath, and then cooled and dried to obtain the low eutectic solvent.

8. Use of the carbonate eluent according to any one of claims 1 to 5 in the remediation of uranium contaminated soil.

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