Peroxide layered titanic acid uranium extraction adsorbent as well as preparation method and application thereof

Abstract

The invention relates to the field of uranium adsorbent materials, and discloses a uranium extraction adsorbent and a preparation method and application thereof.The preparation method comprises the steps that layered titanic acid H1.07Ti1.73O4 with plate-shaped morphology is added into a hydrogen peroxide solution, stirring and suction filtration are conducted, and layered titanic acid with peroxide bond intercalation is obtained, namely the uranium extraction adsorbent is obtained. The uranium extraction adsorbent prepared by the method is mild in reaction condition, simple to operate and high in repeatability, and the layered oxide prepared by the method is controllable in morphology and microstructure, ultrafast in adsorption rate and high in stability. When the adsorbent is placed in seawater, selective adsorption of UO2 < 2 + > can be achieved, competitive adsorption of interfering substances such as vanadium ions in the seawater can be effectively avoided, low-concentration diffusion limitation is overcome, the adsorption efficiency of low-concentration uranyl ions is remarkably improved, and a foundation is laid for large-scale seawater uranium extraction.

Description

Technical Field

[0001] This invention relates to the field of uranium adsorbent materials technology, specifically to a peroxide-coated layered titanate uranium extraction adsorbent, its preparation method, and its application. Background Technology

[0002] Uranium, as a key strategic resource for nuclear energy development, is of great significance for energy security and environmental protection through its sustainable recovery. With the dwindling reserves of terrestrial uranium mines, the extraction of uranium from seawater (approximately 4.5 billion tons of uranium) and nuclear wastewater has become a global research hotspot. However, the concentration of uranium in actual water bodies is extremely low (only 3.3 ppb in seawater) and contains high concentrations of competing ions (such as vanadium, sodium, and potassium). Therefore, finding efficient, stable, and selective uranium extraction technologies and materials is crucial.

[0003] Among existing technologies (adsorption, electrochemistry, and membrane separation), adsorption is the most promising method due to its simplicity, scalability, and cost-effectiveness. Among many adsorbents, layered titanate has attracted widespread attention due to its high specific surface area and strong interlayer modifiability. Despite its obvious advantages, traditional layered titanate adsorbents have insurmountable limitations: (1) kinetic hysteresis: the narrow interlayer spacing severely hinders UO2. 2+ (1) Diffusion, resulting in an excessively long adsorption equilibrium time (>24 hours); (2) Low actual adsorption capacity. Conventional methods often modify layered compounds through surface functional group modification, but these methods cannot fundamentally solve the above problems. Summary of the Invention

[0004] In order to overcome the defects of the existing technology, the present invention aims to provide an adsorbent for the rapid adsorption of uranyl ions using layered titanic acid peroxide. The preparation method has mild reaction conditions, simple operation, and high reproducibility. The morphology and microstructure of the layered oxide prepared by this method are controllable, and the adsorption rate is ultra-fast and highly stable.

[0005] To achieve the above objectives, the present invention provides a method for preparing a layered titanate peroxide uranium extraction adsorbent, comprising:

[0006] Layered titanate H with plate-like morphology 1.07 Ti 1.73 O4 is added to a hydrogen peroxide solution, stirred and filtered to obtain layered titanate with peroxy bond intercalation, which is the peroxide layered titanate uranium extraction adsorbent.

[0007] It should be noted that the plate-like morphology in this invention refers to a multi-layered morphology formed by stacking layers. The layered titanate with the plate-like morphology is a layered structure formed by stacking single layers of TiO2 along the O10 direction. Its layers are negatively charged, and the interlayers are H3O. + .

[0008] The layered titanate H with plate-like morphology in this invention 1.07 Ti 1.73 O4 is a known compound that can be prepared by conventional methods or by the following methods provided in this invention, without limitation.

[0009] The layered titanate H provided by this invention 1.07 Ti 1.73 The preparation method of O4 is as follows:

[0010] Potassium carbonate, lithium carbonate, titanium dioxide, and potassium molybdate were mixed and ball-milled until homogeneous. The resulting powder was then calcined and treated with a low-concentration acid solution to obtain layered titanate H₂ with a plate-like morphology. 1.07 Ti 1.73 O4, wherein the mass ratio of potassium carbonate, lithium carbonate, titanium dioxide, and potassium molybdate is 1~2:0.18~0.36:5:10~20;

[0011] Alternatively, potassium carbonate, lithium carbonate, titanium dioxide, and potassium chloride are mixed and ball-milled until homogeneous. The resulting powder is then calcined and treated with a low-concentration acid solution to obtain layered titanate H₂ with a plate-like morphology. 1.07 Ti 1.73 O4, wherein the mass ratio of potassium carbonate, lithium carbonate, titanium dioxide, and potassium chloride is 1~2:0.18~0.36:5:10~20;

[0012] Alternatively, potassium carbonate, lithium carbonate, and titanium dioxide are mixed and ball-milled until homogeneous. The resulting powder is then calcined and treated with a low-concentration acid solution to obtain layered titanate H₂ with a plate-like morphology. 1.07 Ti 1.73 O4, wherein the mass ratio of potassium carbonate, lithium carbonate, and titanium dioxide is 1~2:0.18~0.36:5;

[0013] Alternatively, potassium hydroxide, lithium hydroxide, titanium dioxide, and water are mixed and hydrothermally heated at 250°C for 24 hours, followed by treatment with a low-concentration acid solution to obtain layered titanate H with a plate-like morphology. 1.07 Ti 1.73 O4.

[0014] As a further preferred embodiment of the present invention, the acid solution is at least one of acetic acid, hydrochloric acid, and sulfuric acid solution, with a concentration of 0.1~2 mol / L.

[0015] As a further preferred embodiment of the present invention, the calcination temperature is 900-1200 ℃.

[0016] As a further preferred embodiment of the present invention, the concentration of the hydrogen peroxide aqueous solution is 20~30 wt.%.

[0017] According to another aspect of the present invention, the present invention also provides a peroxide layered titanate uranium extraction adsorbent, which is prepared by the above-described preparation method.

[0018] According to another aspect of the present invention, the present invention also provides an application of a layered titanate peroxide uranium extraction adsorbent, wherein the uranium extraction adsorbent is placed in a solution containing uranyl ions to achieve adsorption of uranyl ions; then, the uranium extraction adsorbent with adsorbed uranyl ions is placed in a solution of acetic acid, hydrochloric acid, or sulfuric acid with a concentration of 0.05~1.0 mol / L to achieve desorption of uranyl ions. The layered titanate H... 1.07 Ti 1.73 After O4 adsorbs uranyl ions, its layered structure formed by stacked AA layers is transformed into a two-dimensional superlattice structure of stacked ABA layers, where A is the titanate layer and B is the UO2O2 layer.

[0019] According to another aspect of the present invention, the present invention also provides the application of peroxide layered titanate uranium extraction adsorbent in seawater uranium extraction.

[0020] Layered titanates mainly include Z-type and ferriferrite types, among which Z-type layered titanates include H2Ti3O7, H2Ti4O9, and H2Ti5O. 11 In contrast, the TiO6 octahedrons of this invention lack vacancies and cannot coordinate with hydrogen peroxide; while the H of this invention... 1.07 Ti 1.73 O4, due to the vacancies in its octahedral layers, readily coordinates with hydrogen peroxide, thereby increasing the negative charge density of the octahedral layers and the interlayer hydrogen content. + Content and increase interlayer spacing.

[0021] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0022] (1) Traditional uranium extraction adsorbent preparation methods are complex, and the adsorption capacity is low and the selectivity is poor. However, the uranium extraction adsorbent preparation method of the present invention is simple and easy to mass-produce. It has a fast adsorption rate, high adsorption capacity and good selectivity for uranyl ions.

[0023] (2) The uranium extraction adsorbent of the present invention can achieve complete adsorption of uranyl ions within 10 minutes, and the adsorption rate is much higher than that of traditional uranium extraction adsorbents and other layered titanates (conventional titanates can only reach adsorption equilibrium after more than 12 hours).

[0024] (3) The present invention can achieve a maximum adsorption capacity of 549 mg / g for uranyl ions at room temperature, which is far higher than that of traditional uranium extraction adsorbents and is at the international leading level.

[0025] (4) The uranium-enhancing adsorbent of the present invention for UO2 2+It exhibits selective adsorption and can effectively avoid competitive adsorption of interfering substances such as vanadium ions in seawater and reduce interference from cations such as sodium and calcium, overcoming diffusion limitations at low concentrations and significantly improving the adsorption efficiency of low-concentration uranyl ions. When applied to uranium extraction from seawater, this invention generates less pollution and is more environmentally friendly compared to traditional uranium mining. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 For the adsorbent in Example 1: a) XRD patterns before and after adsorption; b) SAED pattern after adsorption.

[0028] Figure 2 The images shown are: a) SEM image of the adsorbent after desorption in Example 1; bd) Energy dispersive X-ray spectroscopy (EDS) images of each element after desorption, where b is U, c is Ti, and d is O.

[0029] Figure 3 The adsorption time efficiency curves of uranium ion adsorbents for Example 1 and Comparative Example 1 are shown.

[0030] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0032] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0033] Example 1

[0034] The preparation method of the peroxide layered titanate uranium extraction adsorbent provided in this embodiment is as follows:

[0035] 1) Mix 2g potassium carbonate, 0.36g lithium carbonate, 5g titanium dioxide, and 20g potassium molybdate, and ball mill until homogeneous. Then, calcine the resulting powder at 1000 ℃ for 5 h. Finally, add the powder to a 0.5 mol / L hydrochloric acid solution and stir at room temperature for 6 h. Filter, wash, and dry to obtain layered titanate H. 1.07 Ti 1.73 O4;

[0036] 2) Add 0.5g of layered titanate H 1.07 Ti 1.73 O4 was added to 50 mL of 30 wt.% hydrogen peroxide aqueous solution, and after filtration and washing, peroxide layered titanate adsorbent (hereinafter also referred to as adsorbent or uranium extraction adsorbent) was obtained.

[0037] The prepared uranium extraction adsorbent samples were subjected to the following experimental tests:

[0038] Adsorption experiment: 0.1 g of layered titanate peroxide adsorbent was placed in 100 mL of 1000 mg / L uranyl nitrate solution and reacted at room temperature for 10 min. After the reaction was completed, layered titanate with intercalated uranyl ions was obtained. Figure 1 The image shows the diffraction pattern of the adsorbent after adsorption of uranyl ions. A superlattice structure is visible after adsorption (XRD shows that the interlayer spacing of the hydrogen peroxide-layered titanate was 0.94 nm, which increased to 1.17 nm after adsorption). Figure 1 As shown, the XRD diffraction peaks are characteristic peaks of the superlattice structure. Figure 1 (a) In addition, in selected area electron diffraction (SAED) patterns, Figure 1 In Figure b), the diffraction points of layered titanate and the diffraction ring of uranyl peroxide can be observed, further proving that the adsorbed product is a superlattice structure.

[0039] ICP analysis was performed on the initial uranyl nitrate solution and the filtrate collected by vacuum filtration after the reaction to detect the change in solution concentration before and after the reaction, combined with the formula... (Where Q is the adsorption capacity, C0 is the initial uranyl ion concentration in the solution, C is the post-reaction uranyl ion concentration in the solution, m is the adsorbent mass, and V is the initial solution volume.) Calculate the adsorption capacity. Assuming adsorbent m is 0.1 g, the initial uranyl ion concentration C0 is 1151.6 mg / L, the post-reaction uranyl ion concentration C is 601.84 mg / L, and V is 100 mL, the adsorption capacity is calculated to be 549 mg / g according to the formula.

[0040] Desorption experiment: Layered titanate containing intercalated uranyl ions was placed in 0.1 mol / L HCl solution and stirred for 30 min to allow the uranyl ions to completely desorb from its interlayer (e.g., Figure 2 EDS analysis showed that Ti and O elements could still be observed after desorption, but the U element signal almost disappeared.

[0041] Stability assessment experiment: The above adsorption-desorption experiment was repeated 10 times. The final experimental results showed that after 10 desorption cycles, the layered titanic acid peroxide could still achieve efficient adsorption within 10 min, proving that it has good cycle stability and the adsorption capacity and adsorption rate remain unchanged.

[0042] Example 2

[0043] The preparation method of the peroxide layered titanate uranium extraction adsorbent provided in this embodiment is as follows:

[0044] 1) Mix 2g potassium carbonate, 0.36g lithium carbonate, 5g titanium dioxide, and 10g potassium chloride, and ball mill until homogeneous. Then, calcine the resulting powder at 900 ℃ for 5 h. Finally, add the powder to a 0.5 mol / L acetic acid solution and stir at room temperature for 6 h. Filter, wash, and dry to obtain layered titanate H. 1.07 Ti 1.73 O4;

[0045] 2) Add 0.5g of layered titanate H 1.07 Ti 1.73 O4 was added to 50 mL of a 30 wt.% hydrogen peroxide solution, and after filtration and washing, a layered titanium dioxide peroxide adsorbent was obtained.

[0046] The prepared uranium extraction adsorbent samples were subjected to the following experimental tests:

[0047] Adsorption experiment: 0.5 g of layered titanic acid peroxide was placed in 50 mL of 100 mg / L uranyl nitrate solution and reacted at room temperature for 10 min. After the reaction was completed, layered titanic acid with intercalated uranyl ions was obtained, and the filtrate was collected by vacuum filtration.

[0048] ICP analysis was performed on the initial uranyl nitrate solution and the collected filtrate to detect the change in uranyl ions before and after the reaction, combined with the formula... (Where Q is the adsorption capacity, C0 is the uranyl ion concentration in the initial solution, C is the uranyl ion concentration in the solution after the reaction, m is the adsorbent mass, and V is the initial solution volume.) Calculate the adsorption capacity, which is 102 mg / g.

[0049] Desorption experiment: Accordion-structured titanium dioxide nanoparticles with intercalated uranyl ions were placed in 0.1 mol / L HCl solution and stirred for 12 h, and uranyl ions were desorbed from the interlayer.

[0050] Stability assessment experiment: The above adsorption-desorption experiment was repeated 10 times. The final experimental results showed that after 10 desorption cycles, the layered titanic acid peroxide could still achieve efficient adsorption within 10 min, proving that it has good cycle stability and the adsorption capacity and adsorption rate remain unchanged.

[0051] Comparative Example 1

[0052] As a comparative experiment to Example 1, the difference lies in that layered titanate H... 1.07 Ti 1.73O4 is used directly as an adsorbent for uranium extraction without hydrogen peroxide treatment.

[0053] The uranium extraction adsorbents of Example 1 and Comparative Example 1 were compared and tested: 0.2 g of adsorbent was placed in 20 mL of 100 mg / L uranyl nitrate solution, and the reactions were carried out at room temperature for 10 min, 20 min, 30 min, 300 min, 600 min, and 720 min, respectively. The resulting adsorption time efficiency curves are shown below. Figure 3 As shown, the adsorbent of Example 1 can achieve rapid adsorption equilibrium within 10 minutes, while the adsorption equilibrium of Comparative Example 1 takes a particularly long time (more than 12 hours) and has an extremely low adsorption capacity.

[0054] Example 3

[0055] The application of the peroxide-layered titanate uranium extraction adsorbent in seawater uranium extraction provided in this embodiment is as follows:

[0056] 10g of the layered titanate peroxide adsorbent prepared in Example 1 was placed in 50 L of simulated seawater (containing UO2). 2+ VO 3- Na + K + Ca 2+ Mg 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ After adsorption for 30 min in the (elemental composition shown in Table 1), it was found that it had excellent selective adsorption characteristics for acyl ions, and the adsorption capacity was measured to be 0.5 mg / g.

[0057] Table 1 Simulated seawater ratio

[0058]

[0059] As shown in Table 1, the adsorbent of the present invention, when placed in simulated seawater, exhibits extremely low UO2 levels. 2+ In the case of ions, it exhibits resistance to UO2. 2+ The excellent selective adsorption of ions effectively solves the strong competitive adsorption of other cations (such as sodium and calcium), and also has excellent selective adsorption properties for UO2. 2+ The ion adsorption capacity is high. Furthermore, in this simulated seawater environment, after 30 days of continuous operation (repeated adsorption-desorption), a uranyl ion extraction yield of up to 15.4 mg / g can be achieved, demonstrating its high processing efficiency and significant cost-effectiveness.

[0060] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing a peroxo layered titanate uranium extraction adsorbent, characterized by, The acid solution is at least one of acetic acid, hydrochloric acid, and sulfuric acid solution, and has a concentration of 0.1-2 mol / L. The layered titanate H 1.07 Ti 1.73 O4 is added to a hydrogen peroxide solution, and stirring and filtration are performed to obtain a layered titanate having a peroxide interlayer, i.e., a peroxidized layered titanate uranium extraction adsorbent.

2. The method of claim 1, wherein the peroxotitanate uranium extraction adsorbent is prepared by the steps of: The layered titanate H 1.07 Ti 1.73 O4 is prepared by the following method: By adding or not adding potassium molybdate or potassium chloride, potassium carbonate, lithium carbonate and titanium dioxide are mixed and ball milled uniformly, and then the ball milled mixture powder is calcined and treated by a low concentration acid solution to obtain layered titanium acid H 1.07 Ti 1.73 O4 with a platy morphology 3. The method of claim 2, wherein the peroxotitanate uranyl extraction adsorbent is prepared by the steps of: The mass ratio of the potassium carbonate, lithium carbonate, and titanium dioxide is 1-2:0.18-0.36:

5.

4. The method of claim 2, wherein the peroxotitanate uranyl extraction adsorbent is prepared by the steps of: The calcination temperature is 900-1200 ℃.

5. The method of claim 2, wherein the peroxotitanate uranium extraction adsorbent is prepared by the process comprising: The concentration of the hydrogen peroxide solution is 20-30 wt.%.

6. The method of claim 1, wherein the peroxotitanate uranium extraction adsorbent is prepared by the process comprising: The preparation method is prepared by any one of claims 1-6.

7. A peroxo layered titanate uranium extraction adsorbent characterized by, 10. Use of the peroxidized layered titanic acid uranium extraction adsorbent of claim 6 in seawater uranium extraction.

8. Use of the peroxidic layered titanate uranium extraction adsorbent according to claim 7, characterized in that The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H 1.07 Ti 1.73 The layered titanic acid H < 9. Use of a peroxidic layered titanic acid uranyl-extracting adsorbent according to claim 7, characterized in that, The layered titanate H 1.07 Ti 1.73 Upon adsorption of uranyl ions, the single-layered structure of H2Ti4O9changes to a two-dimensional superlattice structure stacked in A-B-A, where A is a titanate layer and B is a UO2O2layer. ​

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