Layered vanadyl oxy hybrid material, its preparation method and application

Abstract

This invention discloses a layered vanadium oxy-oxide hybrid material, its preparation method, and its application. The method includes the following steps: 1. Adding vanadium pentoxide to deionized water and stirring to obtain an orange-yellow solution I; 2. Adding tetrahydropyrrole solution dropwise to the orange-yellow solution I and stirring to obtain an orange-yellow solution II; 3. Adjusting the pH of the orange-yellow solution II to weakly acidic and stirring to obtain an orange-yellow solution III; 4. Transferring the orange-yellow solution III to the inner liner of a polytetrafluoroethylene reactor, tightening the reactor, and placing it in an oven at 180-200℃ for hydrothermal synthesis for 5 days. After the reaction is completed, filtering is performed to obtain a black solid product; 5. Centrifuging and washing the black solid product several times, and then drying it to obtain the layered vanadium oxy-oxide hybrid material [C4H8NH2]V3O7, with space group P21 / c. This invention not only has a simple and low-cost preparation process, but also [C4H8NH2]V3O7 has good radiation resistance, acid and alkali resistance, and thermal stability, enabling efficient separation and recovery of uranium and europium from radioactive wastewater associated with rare earth minerals.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically a layered vanadium-oxygen hybrid material, its preparation method, and its application. Background Technology

[0002] my country has relatively abundant mineral resources containing associated radioactive elements, and there are many types of ores that can be developed, such as rare earth minerals, zircon minerals, tantalum-niobium minerals, and vanadium minerals. These ores usually contain naturally occurring radioactive elements such as uranium, thorium, and radium. During the mining process, radioactive wastewater from rare earth associated minerals is easily generated, posing a potential risk of radioactive pollution to my country's ecological environment.

[0003] Currently, the adsorption materials used to treat radioactive wastewater are limited by problems such as poor selective adsorption performance, narrow applicable pH range and complex preparation process, and can no longer meet the treatment needs of radioactive wastewater from rare earth associated minerals. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a layered vanadium-oxygen hybrid material, its preparation method, and its application. This material not only has a simple and low-cost preparation process, but also produces [C4H8NH2]V3O7 with excellent radiation resistance, acid and alkali resistance, and thermal stability. Furthermore, it can simultaneously and efficiently separate and recover uranium and europium from radioactive wastewater associated with rare earth minerals.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A layered vanadium-oxygen hybrid material with the chemical formula [C4H8NH2]V3O7 and space group P21 / c.

[0007] Furthermore, the layered vanadium-oxygen hybrid material is resistant to 400 kGy of γ and β particle radiation, has a decomposition temperature above 350 °C, and can tolerate pH values ​​of 1.5–13.5.

[0008] A method for preparing a layered vanadium-oxygen hybrid material includes the following steps:

[0009] Step 1: Add vanadium pentoxide to deionized water at a molar ratio of 1:(100-130), stir, and obtain an orange-yellow solution I;

[0010] Step 2: Add tetrahydropyrrole solution with a concentration of 211 mg / g to orange-yellow solution I at a volume ratio of (40-50 mL): (1-4 mL), stir, and obtain orange-yellow solution II;

[0011] Step 3: Adjust the pH of orange-yellow solution II to weakly acidic, stir, and obtain orange-yellow solution III;

[0012] Step 4: Transfer the orange-yellow solution III into the inner liner of the polytetrafluoroethylene reactor, tighten the reactor, and place it in an oven at 180-200℃ for hydrothermal synthesis for 5 days. After the reaction is completed, filter to obtain a black solid product.

[0013] Step 5: After centrifuging and washing the black solid product several times, dry it to obtain the layered vanadium-oxygen hybrid material [C4H8NH2]V3O7.

[0014] Furthermore, the stirring in steps 1 and 3 is performed at a speed of 300-500 r / min at room temperature using magnetic stirring for 1 hour.

[0015] Furthermore, the stirring in step 2 is performed at a speed of 300-500 r / min at room temperature using magnetic stirring for 5 hours.

[0016] Furthermore, in step 3, acetic acid is used to adjust the pH of the orange-yellow solution II to 4.5–6.5.

[0017] Furthermore, the washing in step 5 involves centrifuging and washing three times each with deionized water and anhydrous ethanol.

[0018] Furthermore, the drying in step 5 is carried out in an oven at 60–90°C for 18–30 hours.

[0019] Application of layered vanadium-oxygen hybrid materials in the treatment of radioactive wastewater from rare earth associated minerals, used to adsorb uranium and europium in the wastewater.

[0020] Compared with the prior art, the present invention has the following technical effects:

[0021] The organic amine ion [THPH] in the layered vanadium-oxygen hybrid material [C4H8NH2]V3O7 of the present invention + It can efficiently exchange uranium and europium, and simultaneously separate and recover uranium and europium from radioactive wastewater from rare earth associated minerals. Moreover, [C4H8NH2]V3O7 has radiation resistance, acid and alkali resistance, and thermal stability. Specifically, it can withstand 400 kGy of γ and β particle radiation, has a decomposition temperature of not less than 350℃, and can exist stably under pH conditions of 1.5 to 13.5. It is suitable for treating radioactive wastewater from rare earth associated minerals under different conditions, thus meeting the current needs of my country for the treatment of radioactive wastewater from rare earth associated minerals.

[0022] This invention employs a hydrothermal method to adjust the inorganic open framework [V3O7] under the structural guidance of the organic amine tetrahydropyrrole (C4H8NH). n- The structure is [C4H8NH2]. n+ It inserts as a cation into the inorganic open framework [V3O7]. n-In the layered structure, the open-framework layered vanadium-oxygen hybrid material [C4H8NH2]V3O7 is obtained. The process is not only simple and low-cost, but also has a high yield of up to 86%. Moreover, by controlling the pH, reaction time and reaction temperature, open-framework layered vanadium-oxygen hybrid materials with different morphologies and chemical properties can be obtained to meet different application requirements.

[0023] When the [C4H8NH2]V3O7 of this invention is applied to the treatment of radioactive wastewater from rare earth associated minerals, organic amine ions [THPH] are produced. + It can efficiently exchange uranium and europium, simultaneously separating and recovering uranium and europium. It not only has a high ion response rate, reaching equilibrium in just 15 minutes, but also a high partition coefficient. Specifically, in real radioactive wastewater containing rare earth minerals, the partition coefficient K of uranium is... d U =2.90×10 3 mL / g, europium partition coefficient K d Eu =6.92×10 2 mL / g, achieving removal rates of R for uranium and europium respectively. U =74.37% and R Eu =40.89%; In simulated radioactive wastewater containing rare earth associated minerals, K d U =5.69×10 3 mL / g, K d Eu =1.27×10 3 mL / g, R U =85.04%, R Eu =55.90%; In addition, after ion exchange, the [C4H8NH2]V3O7 adsorbed with uranium and europium is eluted with 0.85mol / L KCl solution to recover uranium and europium. The layered vanadium-oxygen crystal structure remains unchanged, so it can be reused many times, reducing the cost of rare earth associated mineral wastewater treatment. Attached Figure Description

[0024] Figure 1 The XRD pattern of the layered vanadium-oxygen hybrid material prepared in Example 1 of this invention;

[0025] Figure 2 The XRD patterns of the layered vanadium-oxygen hybrid material prepared in Example 1 of this invention before and after irradiation;

[0026] Figure 3 The XRD patterns of the layered vanadium-oxygen hybrid material prepared in Example 1 of this invention at different pH values;

[0027] Figure 4The layered vanadium-oxygen hybrid material prepared in Example 1 of this invention demonstrates its ability to treat uranium and europium in simulated rare earth associated mineral wastewater;

[0028] Figure 5 The ability of the layered vanadium-oxygen hybrid material prepared in Example 2 of this invention to treat uranium and europium in real rare earth associated mineral wastewater;

[0029] Figure 6 These are scanning electron microscope images of the layered vanadium-oxygen hybrid material prepared in Example 1 of this invention before and after ion exchange;

[0030] Figure 7 The image shows the TG-DSC spectrum of the layered vanadium-oxygen hybrid material prepared in Example 1 of this invention. Detailed Implementation

[0031] The specific content of the present invention will be further explained in detail below with reference to the embodiments.

[0032] Example 1

[0033] Step 1: Add 3.64g of vanadium pentoxide to 40mL of deionized water and stir magnetically at 420r / min for 1h at room temperature to obtain orange-yellow solution I.

[0034] Step 2: Add 1.8 mL of tetrahydropyrrole solution with a concentration of 211 mg / g to the orange-yellow solution I, and stir magnetically for 5 h at 420 r / min at room temperature to obtain orange-yellow solution II;

[0035] Step 3: Add acetic acid to orange-yellow solution II, adjust the pH to 5, and stir magnetically at 420 r / min for 1 h at room temperature to obtain orange-yellow solution III;

[0036] Step 4: Transfer the orange-yellow solution III into a 100mL polytetrafluoroethylene reactor liner, tighten the reactor, place it in an oven at 190℃, and react for 5 days. After the reaction is complete, filter to obtain a black solid product.

[0037] Step 5: Place the black solid product in a 100 mL centrifuge tube, wash it three times each with deionized water and anhydrous ethanol, and then place it in an oven at 80 °C for 24 h to obtain the layered vanadium oxy hybrid material [C4H8NH2]V3O7.

[0038] from Figure 1 It can be seen that the layered vanadium-oxygen hybrid material [C4H8NH2]V3O7 prepared by hydrothermal method in Example 1 has high purity and high crystallinity.

[0039] from Figure 2It can be seen that after the layered vanadium-oxygen hybrid material prepared in Example 1 was irradiated with γ and β particles at 300 kGy and 400 kGy, the intensity of the diffraction peaks hardly changed compared with the original sample (pristine product) that was not irradiated with γ and β particles, and the original structure was still maintained. This indicates that the layered vanadium-oxygen hybrid material prepared in Example 1 can withstand γ and β particle radiation of 400 kGy and has good radiation resistance stability required for the removal of radionuclides.

[0040] from Figure 3 It can be seen that the intensity of the diffraction peak of the layered vanadium-oxygen hybrid material prepared in Example 1 hardly changed compared with the original sample at different pH values, indicating that it can exist stably in the pH range of 1.5 to 13.5 and has good acid and alkali resistance.

[0041] At room temperature (25°C), the layered vanadium-oxygen hybrid material prepared in Example 1 was added to simulated rare earth associated mineral wastewater at a solid-liquid ratio of 1:1000. The concentration of uranium in the simulated rare earth associated mineral wastewater was 5.95 ppm, the concentration of europium was 7.37 ppm, and the concentrations of competing ions Na, Ca, Mg, Al, Fe, and Mn were 24.12 ppm, 29.06 ppm, 24.40 ppm, 12.35 ppm, 17.07 ppm, and 7.63 ppm, respectively. The pH value was 6.3. (See attached results). Figure 4 Table 1;

[0042] from Figure 4 It can be seen that after ion exchange, the partition coefficients of uranium and europium are K and K, respectively. d U =5.69×10 3 mL / g, K d Eu =1.27×10 3 mL / g indicates that in the presence of a large number of competing ions (including alkali metals, alkaline earth metals, and transition metals), the layered vanadium-oxygen hybrid material can selectively exchange ions with uranium and europium in the simulated wastewater.

[0043] In Table 1, C0 represents the concentration of each metal ion in the simulated rare earth associated mineral wastewater. e The concentration of each metal ion in the simulated rare earth associated mineral wastewater after ion exchange, K d The partition coefficients of each metal ion after ion exchange are shown in Table 1. As can be seen from the table, the removal rates of uranium and europium in the wastewater after ion exchange are R0 and R1, respectively. U =85.04%, R Eu =55.90%, indicating that the layered vanadium-oxygen hybrid material prepared in Example 1 has excellent adsorption performance for uranium and europium in rare earth associated mineral wastewater.

[0044] After ion exchange, the layered vanadium-oxygen hybrid material adsorbed with uranium and europium was eluted with a KCl solution of 0.85 mol / L. The crystal structure of the layered vanadium-oxygen hybrid material remained unchanged after elution, indicating that it has good stability and can be used repeatedly, thus reducing the cost of treating rare earth associated mineral wastewater.

[0045] Table 1. Test data of ion exchange performance of layered vanadium-oxygen hybrid materials in simulated rare earth associated mineral wastewater.

[0046]

[0047] Adding the layered vanadium-oxygen hybrid material prepared in Example 1 to radioactive wastewater containing rare earth associated minerals with a uranium concentration of 1.3 ppm can remove uranium from the wastewater to below 30 ppb, meeting the national drinking water standard. This further demonstrates that the layered vanadium-oxygen hybrid material prepared in Example 1 has excellent adsorption performance for uranium in radioactive wastewater containing rare earth associated minerals.

[0048] from Figure 6 It can be seen that, compared with before ion exchange, the nanosheets in the flower-like particles of the layered vanadium-oxygen hybrid material prepared in Example 1 are significantly thinner after ion exchange.

[0049] from Figure 7 It can be seen that the layered vanadium-oxygen hybrid material prepared in Example 1 only begins to decompose at 350°C, indicating that it has good thermal stability.

[0050] Example 2

[0051] Step 1: Add 4.55g of vanadium pentoxide to 50mL of deionized water and stir magnetically at 420r / min for 1h at room temperature to obtain orange-yellow solution I.

[0052] Step 2: Add 3 mL of tetrahydropyrrole solution with a concentration of 211 mg / g to orange-yellow solution I, and stir magnetically for 5 h at room temperature and 420 r / min to obtain orange-yellow solution II;

[0053] Step 3: Add acetic acid to orange-yellow solution II, adjust the pH to 6, and stir magnetically at 420 r / min for 1 h at room temperature to obtain orange-yellow solution III;

[0054] Step 4: Transfer the orange-yellow solution III into a 100mL polytetrafluoroethylene reactor liner, tighten the reactor, place it in an oven at 185℃, and react for 5 days. After the reaction is complete, filter to obtain a black solid product.

[0055] Step 5: Place the black solid product in a 100 mL centrifuge tube, wash it three times each with deionized water and anhydrous ethanol, and then place it in an oven at 80 °C for 24 h to obtain the layered vanadium oxy hybrid material [C4H8NH2]V3O7.

[0056] At room temperature (25°C), the layered vanadium-oxygen hybrid material prepared in Example 2 was added to real rare earth associated mineral wastewater at a solid-liquid ratio of 1:1000. The concentration of uranium in the real rare earth associated mineral wastewater was 3.94 ppm, the concentration of europium was 8.51 ppm, and the concentrations of competing ions Na, Ca, Mg, Al, Fe, and Mn were 1.50 ppm, 14.92 ppm, 1.80 ppm, 10.06 ppm, 14.78 ppm, and 2.35 ppm, respectively. The pH value was 6.7. (See attached results). Figure 5 Table 2;

[0057] from Figure 5 It can be seen that after ion exchange, the partition coefficients of uranium and europium are K and K, respectively. d U =2.90×10 3 mL / g and K d Eu =6.92×10 2 mL / g indicates that the layered vanadium-oxygen hybrid material prepared in Example 2 can selectively exchange ions with uranium and europium in real rare earth associated mineral wastewater.

[0058] In Table 2, C0 represents the concentration of each metal ion in the actual rare earth associated mineral wastewater. e K represents the concentration of each metal ion in the wastewater from real rare earth associated minerals after ion exchange. d The partition coefficients of each metal ion after ion exchange are shown in Table 1. As can be seen from the table, the removal rates of uranium and europium in the wastewater after ion exchange are R0 and R1, respectively. U =74.37%, R Eu =40.89%, indicating that the layered vanadium-oxygen hybrid material prepared in Example 2 has excellent adsorption performance for uranium and europium in rare earth associated mineral wastewater.

[0059] After ion exchange, the layered vanadium-oxygen hybrid material adsorbed with uranium and europium was eluted with a KCl solution of 0.85 mol / L. The crystal structure of the layered vanadium-oxygen hybrid material remained unchanged after elution.

[0060] Table 2. Test data of ion exchange performance of layered vanadium-oxygen hybrid materials in real rare earth associated mineral wastewater.

[0061]

[0062] Example 3

[0063] Step 1: Add 4g of vanadium pentoxide to 40mL of deionized water and stir magnetically at 300r / min for 1h at room temperature to obtain orange-yellow solution I.

[0064] Step 2: Add 1 mL of tetrahydropyrrole solution with a concentration of 211 mg / g to orange-yellow solution I, and stir magnetically for 5 h at 300 r / min at room temperature to obtain orange-yellow solution II;

[0065] Step 3: Add acetic acid to orange-yellow solution II, adjust the pH to 4.5, and stir magnetically at 300 r / min for 1 h at room temperature to obtain orange-yellow solution III;

[0066] Step 4: Transfer the orange-yellow solution III into a 100mL polytetrafluoroethylene reactor liner, tighten the reactor, place it in an oven at 180℃, and react for 5 days. After the reaction is complete, filter to obtain a black solid product.

[0067] Step 5: Place the black solid product in a 100 mL centrifuge tube, wash it three times each with deionized water and anhydrous ethanol, and then place it in an oven at 60 °C for 30 h to obtain the layered vanadium oxy hybrid material [C4H8NH2]V3O7.

[0068] Example 4

[0069] Step 1: Add 3.78g of vanadium pentoxide to 45mL of deionized water and stir magnetically at 500r / min for 1h at room temperature to obtain orange-yellow solution I.

[0070] Step 2: Add 2.5 mL of tetrahydropyrrole solution with a concentration of 211 mg / g to the orange-yellow solution I, and stir magnetically at 500 r / min for 5 h at room temperature to obtain orange-yellow solution II;

[0071] Step 3: Add acetic acid to orange-yellow solution II, adjust the pH to 6.5, and stir magnetically at 500 r / min for 1 h at room temperature to obtain orange-yellow solution III;

[0072] Step 4: Transfer the orange-yellow solution III into a 100mL polytetrafluoroethylene reactor liner, tighten the reactor, place it in an oven at 195℃, and react for 5 days. After the reaction is complete, filter to obtain a black solid product.

[0073] Step 5: Place the black solid product in a 100 mL centrifuge tube, wash it three times each with deionized water and anhydrous ethanol, and then dry it in an oven at 70 °C for 20 h to obtain the layered vanadium oxy-oxygen hybrid material [C4H8NH2]V3O7.

[0074] Example 5

[0075] Step 1: Add 3.9g of vanadium pentoxide to 50mL of deionized water and stir magnetically at 300r / min for 1h at room temperature to obtain orange-yellow solution I.

[0076] Step 2: Add 4 mL of tetrahydropyrrole solution with a concentration of 211 mg / g to orange-yellow solution I, and stir magnetically at 300 r / min for 5 h at room temperature to obtain orange-yellow solution II;

[0077] Step 3: Add acetic acid to orange-yellow solution II, adjust the pH to 5, and stir magnetically at 300 r / min for 1 h at room temperature to obtain orange-yellow solution III;

[0078] Step 4: Transfer the orange-yellow solution III into a 100mL polytetrafluoroethylene reactor liner, tighten the reactor, place it in an oven at 200℃, and react for 5 days. After the reaction is complete, filter to obtain a black solid product.

[0079] Step 5: Place the black solid product in a 100 mL centrifuge tube, wash it three times each with deionized water and anhydrous ethanol, and then dry it in a 90 °C oven for 18 h to obtain the layered vanadium oxy-oxygen hybrid material [C4H8NH2]V3O7.

Claims

1. Use of a vanadyl hybrid material in the treatment of radioactive waste water from rare earth associated mines, characterized in that, Used to adsorb uranium and europium in radioactive wastewater from rare earth associated minerals; The vanadium-oxygen hybrid material, with the chemical formula [C4H8NH2]V3O7 and space group P21 / c, is resistant to 400 kGy of γ and β particle radiation, has a decomposition temperature not lower than 350℃, and can tolerate a pH value of 1.5~13.

5. The preparation method includes the following steps: Step 1: Add vanadium pentoxide to deionized water at a molar ratio of 1:(100~130), stir, and obtain an orange-yellow solution I; Step 2: Add tetrahydropyrrole solution with a concentration of 211 mg / g to orange-yellow solution I at a volume ratio of (40~50):(1~4), stir, and obtain orange-yellow solution II; Step 3: Adjust the pH of orange-yellow solution II to weakly acidic, stir, and obtain orange-yellow solution III; Step 4: Transfer the orange-yellow solution III into the inner liner of the polytetrafluoroethylene reactor, tighten the reactor, and place it in an oven at 180~200℃ for hydrothermal synthesis reaction for 5 days. After the reaction is completed, filter to obtain a black solid product. Step 5: After centrifuging and washing the black solid product several times, dry it to obtain the vanadium oxy-based hybrid material [C4H8NH2]V3O7.

2. Use of the vanadoxy hybrid material according to claim 1 in the treatment of radioactive waste water from rare earth associated mines, characterized in that, The stirring in steps 1 and 3 is performed at a speed of 300-500 r / min at room temperature using magnetic stirring for 1 hour.

3. Use of the vanadoxy hybrid material according to claim 1 in the treatment of radioactive waste water from rare earth associated mines, characterized in that, The stirring in step 2 is performed at a speed of 300~500 r / min at room temperature using magnetic stirring for 5 hours.

4. Use of the vanadoxy hybrid material according to claim 1 in the treatment of radioactive waste water from rare earth associated mines, characterized in that, In step 3, acetic acid is used to adjust the pH of the orange-yellow solution II to 4.5-6.

5.

5. Use of the vanadyl-based hybrid material according to claim 1 in the treatment of radioactive waste water from rare earth associated mines, characterized in that, The washing in step 5 involves centrifuging and washing three times each with deionized water and anhydrous ethanol.

6. Use of the vanadyl-based hybrid material according to claim 1 in the treatment of radioactive waste water from rare earth associated mines, characterized in that, The drying in step 5 is carried out in an oven at 60~90℃ for 18~30 hours.

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