A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field

Abstract

This invention discloses a method for enhancing the uranium separation efficiency of commercial iron powder using an external field, comprising: adding commercial iron powder to a reactor containing fluorine- and uranium-containing wastewater; applying an external weak magnetic field or magneto-optical coupling; and performing uranium separation treatment on the fluorine- and uranium-containing wastewater under continuous stirring. This invention magnetizes the commercial iron powder by introducing a weak magnetic field, thereby attracting Fe... 2+ Migration disrupts the passivation layer on the surface of iron powder, promoting the reaction of U(VI) with Fe. 0 The redox reaction simultaneously strengthens the affinity between the magnetized iron powder particles and the paramagnetic O2 molecules, leading to the formation of γ-FeOOH nanosheets with a high specific surface area on the iron powder surface. The γ-FeOOH surface is rich in oxygen-containing functional groups, which achieve U(VI) separation through the bonding of -OH groups with U(VI). This invention, based on a weak magnetic field, further improves the separation efficiency of commercial iron powder for U(VI) in fluoride- and uranium-containing wastewater by coupling with an optical field.

Description

Technical Field

[0001] This invention belongs to the field of uranium separation technology, and more specifically, this invention relates to a method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field. Background Technology

[0002] UF6 is an important compound in the nuclear fuel production process, leading to the generation of fluorine- and uranium-containing wastewater in uranium enrichment plants and nuclear fuel (assembly) manufacturing plants. In this fluorine- and uranium-containing wastewater, FU bonds to form UO2F. + UO2F2, UO2F3 - The presence of complexes hinders the extraction and separation of fluoride- and uranium-containing wastewater, while traditional processes (chemical precipitation, ion exchange, and adsorption) are gradually losing their advantages due to their cumbersome processes and high costs. Therefore, there is an urgent need to develop new technologies for treating fluoride- and uranium-containing wastewater that are lower in cost, more efficient, and more environmentally friendly.

[0003] Currently, nano-zero-valent iron (nZVI) is considered the most promising new method to replace traditional processes for treating fluorine- and uranium-containing wastewater. NZVI has advantages in uranium separation from fluorine- and uranium-containing wastewater due to its better ability to be injected into aquifer systems, higher reaction surface area, and faster and more complete reaction. However, NZVI has significant limitations in practical applications, such as easy oxidation and difficulty in long-term storage. In solution systems, the surface of NZVI is easily oxidized to form a passivation layer, which significantly reduces its performance in removing uranium in solution. Simultaneously, the aggregation of NZVI reduces its fluidity on the subsurface, further affecting its reactivity. To address these issues, researchers have conducted extensive modification studies on NZVI. By using supports (attapulgite, illite, montmorillonite, bentonite, silica-based mesoporous or nanomaterials, magnesium hydroxide nanocrystals, and carbon-based porous supports) during the preparation of NZVI, researchers have significantly reduced the aggregation of NZVI and obtained a narrower size distribution of the synthesized nZVI. Although researchers have solved the stability problem of nZVI by using surface carriers, they still face problems such as complex preparation procedures and high costs, which limit the large-scale use of nZVI.

[0004] From a cost perspective, lower-priced commercial iron powder is an ideal alternative to nano-zero-valent iron. However, although both have the same composition, commercial iron powder has a large particle size, resulting in extremely weak reducing power and a very low specific surface area of ​​the oxides formed. Therefore, enhancing the reducing power of commercial iron powder, controlling the structure of oxidation products, and overcoming the "size gap" between commercial iron powder and nano-zero-valent iron are key to achieving efficient uranium separation from fluorine- and uranium-containing waste liquids. Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0006] To achieve these objectives and other advantages of the present invention, a method for enhancing the uranium separation efficiency of commercial iron powder using an external field is provided, comprising the following steps: adding commercial iron powder to a reactor containing fluorine- and uranium-containing wastewater, and performing uranium separation treatment on the fluorine- and uranium-containing wastewater under the action of an external field and continuous stirring.

[0007] Preferably, the external field includes a weak magnetic field or magneto-optical coupling.

[0008] Preferably, the specific method of the external field effect is to place a weak magnetic field around or at the bottom of the reactor;

[0009] Preferably, the specific method of the external field action is as follows:

[0010] (1) Place a weak magnetic field around or at the bottom of the reactor;

[0011] (2) Based on (1), an external light source is added to irradiate the reactor and form magneto-optical coupling.

[0012] Preferably, the commercial iron powder is in the micron range, more preferably in the 1μm range; the amount of commercial iron powder added is 0.5–2.5 g / L, more preferably 0.5 g / L.

[0013] Preferably, the stirring speed is 300-500 r / min.

[0014] Preferably, the weak magnetic field is either a uniform magnetic field or a non-uniform magnetic field.

[0015] Preferably, the strength of the weak magnetic field is 3 to 10 mT, more preferably 10 mT.

[0016] Preferably, the external light source is a 200-400W xenon lamp equipped with an AM1.5G filter.

[0017] Preferably, in the fluoride- and uranium-containing wastewater, the U(VI) concentration is 20–500 mg / L, and the F... - The molar ratio with U(VI) is 0 to 130:1, and the pH value is 3 to 10, more preferably pH = 4 to 6.

[0018] This invention offers at least the following beneficial effects: It enhances the separation efficiency of commercial iron powder for U(VI) in fluorine- and uranium-containing environments by introducing a weak magnetic field. On one hand, the weak magnetic field magnetizes the commercial iron powder, attracting Fe... 2+ Migration disrupts the passivation layer on the surface of iron powder, promoting the reaction of U(VI) with Fe. 0On the one hand, the magnetized iron powder particles exhibit a strong affinity for paramagnetic O2 molecules, leading to the formation of γ-FeOOH nanosheets with a high specific surface area on the iron powder surface. The γ-FeOOH surface is rich in oxygen-containing functional groups, which achieve U(VI) separation through the bonding of -OH groups with U(VI). Furthermore, influenced by the magnetic field gradient force, the angle between the surface γ-FeOOH nanosheets and the iron powder particles is larger, resulting in the formation of a fractal composite structure between the iron powder and the surface γ-FeOOH nanosheet array. This significantly enhances the affinity of commercial iron powder for UO2. 2+ The adsorption capacity was assessed. Specifically, 1μm commercial iron powder, under a weak magnetic field enhancement, achieved a uranium extraction rate of 94.2% after 150 minutes of reaction, compared to 91.8% after 260 minutes without a weak magnetic field, indicating a 110-minute reduction in equilibrium time. In fluorine-containing systems, the 1μm commercial iron powder under weak magnetic field enhancement exhibited a fluoride ion adaptability of 36:1 (fluorine-uranium molar ratio).

[0019] This invention, based on a weak magnetic field, further enhances the separation efficiency of commercial iron powder for U(VI) in fluoride- and uranium-containing wastewater through magneto-optical coupling by coupling an optical field. During this process, photogenerated electrons effectively reduce U(VI) adsorbed on γ-FeOOH nanosheets to U(IV), compressing the equilibrium time for U(VI) separation by commercial iron powder to within 60 minutes. Furthermore, even with a fluoride-uranium molar ratio as high as 125:1, the extraction rate of U(VI) by commercial iron powder remains above 90%. At different U(VI) concentrations (50–200 mg / L), the extraction rate of U(VI) by magneto-optically coupled iron powder reaches above 90% after 60 minutes of reaction. Measurements of the transient photocurrent response of commercial iron powder under light irradiation and magneto-optical coupling revealed that the photocurrent increased from 0.223 × 10⁻⁶ under light irradiation alone to 0.223 × 10⁻⁶ under light irradiation alone. -5 A / cm 2 Increased to 0.326×10 -5 A / cm 2 Furthermore, the continuous upward shift of the current baseline demonstrates that the presence of a magnetic field accelerates the electrochemical corrosion process of commercial iron powder.

[0020] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0021] Figure 1 This is a comparison chart of the U(VI) extraction rates of commercial iron powder under different magnetic field strengths (0 mT (no magnetic field), 3.5 mT, 7 mT, 10 mT) in Example 1;

[0022] Figure 2This is a comparison chart of the U(VI) extraction rates of commercial iron powder under different types of magnetic fields (uniform and non-uniform magnetic fields) in Example 2;

[0023] Figure 3 This is a comparison chart of the U(VI) extraction rates of weak magnetic field enhanced iron powder with different particle sizes (100nm, 1μm, 50μm, 150μm) in Example 3.

[0024] Figure 4 This is a comparison chart showing the time required for U(VI) extraction of commercial iron powder to reach equilibrium under conditions of with and without weak magnetic field enhancement in Example 4.

[0025] Figure 5 This is a comparison chart of the U(VI) extraction rate of commercial iron powder enhanced by a weak magnetic field in the presence or absence of fluoride ions in Example 5.

[0026] Figure 6 This is a comparison chart of the U(VI) extraction rates of commercial iron powder enhanced by a weak magnetic field under different fluorine-uranium molar ratios (25:1, 36:1, 48:1, 60:1) in Example 6.

[0027] Figure 7 This is a comparison chart of the U(VI) extraction rates of commercial iron powder with and without weak magnetic field enhancement at different pH levels (3-9) in Example 7.

[0028] Figure 8 Different anions (NO3) in Example 8 - SO4 2- Cl - C2O4 2- Comparison of U(VI) extraction rates of commercial iron powder enhanced by a weak magnetic field under different conditions;

[0029] Figure 9 The images show the FT-IR spectra of commercially available iron powder after uranium separation and the original commercially available iron powder in Example 4.

[0030] Figure 10 SEM images (a) and (b) of commercial iron powder uranium separation without weak magnetic field enhancement in Example 4 are shown.

[0031] Figure 11 The XRD patterns of commercial iron powder after uranium separation and the original commercial iron powder are shown in Example 4.

[0032] Figure 12 This is a comparison chart of the U(VI) extraction rates of commercial iron powder enhanced by no external field, only a weak magnetic field, and magneto-optical coupling in Example 9.

[0033] Figure 13 This is a comparison chart of the U(VI) extraction rates of commercial iron powder enhanced by magneto-optical coupling at different pH levels (3-10) in Example 10;

[0034] Figure 14 This is a comparison chart of the U(VI) extraction rates of commercial iron powder enhanced by magneto-optical coupling under different fluorine-uranium molar ratios (0:1, 6.3:1, 12.5:1, 18.8:1, 25:1, 62.5:1, 125:1) in Example 11.

[0035] Figure 15 This is a comparison chart of the U(VI) extraction rates of magneto-optical coupled commercial iron powder at different initial U(VI) concentrations (50, 100, 150, 200 mg / L) in Example 12.

[0036] Figure 16 The transient photocurrent response of commercial iron powder U(VI) separation experiment under light illumination and magneto-optical coupling without magnetic field in Example 13 is shown. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0038] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0039] The magnetic field and light field manipulation methods, as well as the U(VI) separation experiment, are detailed in the following embodiments:

[0040] Magnetic field control methods: Two different types of magnetic fields, uniform and non-uniform, were used, obtained through the following methods: I. Uniform magnetic field: A uniform magnetic field with adjustable strength was provided using a custom-made coil (inner diameter 54mm, outer diameter 74mm, height 50mm, 400 turns, resistance 1.8Ω). The magnetic field strength was adjusted by changing the DC current intensity. II. Non-uniform magnetic field: A non-uniform magnetic field was provided using a permanent magnet (40*5*80mm). The placement method and magnetic field strength were adjusted by controlling the magnet's position and distance from the reaction vessel. A teslameter was used to measure the magnetic field strength in each group of experiments.

[0041] Light field modulation method: U(VI) separation experiment was carried out using a BL-GHX-V photochemical reactor. A 300W xenon lamp and an AM1.5G filter were used as the light source. The wavelength of the incident light was modulated using a bandpass filter, and the light intensity was detected using an illuminance meter.

[0042] U(VI) separation experiment: Simulated solutions of fluoride- and uranium-containing wastewater of appropriate concentrations were prepared using UO2(NO3)2·6H2O and NaF. The pH of the solution was adjusted using HCl and NaOH. The fluoride- and uranium-containing solution was added to a beaker, followed by commercial iron powder. An external mechanical stirrer was used to continuously stir the reaction at a speed of 400 r / min. The experiment was conducted under a set magnetic field (or magneto-optical coupling) condition. During the experiment, 0.35 ml of fluoride- and uranium-containing wastewater was taken from the glass bottle at different time points. The uranium solution was filtered through a 0.25 μm filter. 0.25 ml of the filtered fluorine-containing uranium solution was added to a prepared azoarsine III chromogenic reagent solution (resin solution components: 7.4 ml deionized water, 2 ml buffer solution prepared from CH3COONa and NaClO3, 0.35 ml azoarsine III solution). The mixed reagent solution was shaken thoroughly, and the U(VI) concentration in the solution was measured using a UV spectrophotometer with a wavelength set to 651.8 nm. The U(VI) extraction rate was calculated as follows:

[0043] extraction efficiency(%)=(1-C t / C0)×100%

[0044] In the formula, C0 (mg / L) is the initial concentration of U(VI), C t (mg / L) represents the concentration of U(VI) after reaction time t.

[0045] Example 1

[0046] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0047] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 5 using HCl and NaOH.

[0048] S2. Add 50 ml of fluorine-containing uranium-containing solution to a 100 ml beaker, and then add 25 mg of 1 μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400 r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 0 mT (no magnetic field), 3.5 mT, 7 mT or 10 mT, and the reaction time is 60 min.

[0049] This embodiment experimentally investigated the U(VI) extraction rate of commercial iron powder under different magnetic field intensities, and the results are as follows: Figure 1As shown, the extraction rate of U(VI) gradually increases with the increase of magnetic field strength. After 60 minutes of reaction at a magnetic field strength of 10 mT, the extraction rate of U(VI) is 25% higher than that at 0 mT (no magnetic field).

[0050] Example 2

[0051] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0052] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 5 using HCl and NaOH.

[0053] S2. Add 50 ml of fluorine-containing uranium-containing solution to a 100 ml beaker, and then add 25 mg of 1 μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400 r / min; place a uniform or non-uniform magnetic field around the beaker with a magnetic field strength of 10 mT, and the reaction time is 60 min.

[0054] This embodiment tested the U(VI) extraction rate of commercial iron powder under different magnetic fields, and the results are as follows: Figure 2 As shown, the type of weak magnetic field (i.e., uniform and non-uniform magnetic fields) has a limited impact on the extraction rate of U(VI).

[0055] Example 3

[0056] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0057] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 5 using HCl and NaOH.

[0058] S2. Add 50 ml of fluorine-containing uranium-containing solution to a 100 ml beaker, then add 25 mg of commercial iron powder (particle sizes of 1 μm, 50 μm, and 150 μm) or 100 nm nano-zero valent iron; place an external mechanical stirrer to continuously stir the reaction at a speed of 400 r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 10 mT, and the reaction time is 60 min.

[0059] This embodiment tested the U(VI) extraction rate of iron powder with different particle sizes, and the results are as follows: Figure 3As shown, 100nm nano-zero valent iron is sufficiently reactive, and its aggregation is more compact in the presence of a weak magnetic field, resulting in an extraction rate of only 67.1% for U(VI) from 100nm nano-zero valent iron. In contrast, the lower-priced 1μm commercial iron powder achieves an extraction rate of 61% for U(VI) after 60 minutes of reaction, which is close to that of 100nm nano-zero valent iron.

[0060] Example 4

[0061] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0062] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 5 using HCl and NaOH.

[0063] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 0mT (no magnetic field) or 10mT, and react until the iron powder separates from the uranium and reaches equilibrium.

[0064] This embodiment experimentally investigated the time required for U(VI) extraction from commercial iron powder to reach equilibrium with and without weak magnetic field enhancement. The results are as follows: Figure 4 As shown, it can be seen that the extraction rate of U(VI) from 1μm commercial iron powder can reach 94.2% after 150 min of reaction under weak magnetic field enhancement. Compared with the extraction rate of 91.8% after 260 min of reaction without weak magnetic field, the equilibrium time is shortened by 110 min.

[0065] Example 5

[0066] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0067] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein the U(VI) concentration is 100 mg / L and the NaF concentration is... - The concentration is 0 or 100 mg / L, and the pH of the solution is adjusted to 5 using HCl and NaOH.

[0068] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 40r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 10mT, and the reaction time is 60min.

[0069] This embodiment experimentally investigated the U(VI) extraction rate of commercial iron powder enhanced by a weak magnetic field in the presence / absence of fluoride ions. The results are as follows: Figure 5 As shown, when the fluoride ion concentration is 100 mg / L, the extraction rate of U(VI) after 60 min of reaction is not significantly reduced compared to the absence of fluoride ions. Furthermore, in the solution containing 100 mg / L fluoride ions, the extraction rate of U(VI) by iron powder under the presence of a magnetic field is higher in the first 40 min than in the absence of fluoride ions.

[0070] Example 6

[0071] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0072] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein the U(VI) concentration is 100 mg / L, and the fluoride-uranium molar ratio is 25:1, 36:1, 48:1 or 60:1. Adjust the pH of the solution to 5 using HCl and NaOH.

[0073] S2. Add 50 ml of fluorine-containing uranium-containing solution to a 100 ml beaker, and then add 25 mg of 1 μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400 r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 10 mT, and the reaction time is 60 min.

[0074] This embodiment experimentally investigated the U(VI) extraction rate of commercial iron powder enhanced by a weak magnetic field under different fluorine-uranium molar ratios. The results are as follows: Figure 6 As shown, it can be seen that the extraction rate of U(VI) only begins to decrease significantly when the fluorine-uranium molar ratio reaches 36:1 or higher. Combined with the higher separation efficiency of commercial iron powder for uranium in the first 40 minutes of a fluorine- and uranium-containing (100 mg / L) solution enhanced by a weak magnetic field in Example 5, it can be concluded that when the fluorine-uranium molar ratio is less than 36:1, the extraction rate of U(VI) decreases significantly. - The presence of Fe 2+ Bonding allows Fe to migrate with magnetic field lines 2+ The Coulomb repulsion in the aggregation region decreases, while when F - When the concentration is too high, it reacts with UO2. 2+ The increased complexation reaction caused the extraction rate of U(VI) to begin to decrease.

[0075] Example 7

[0076] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0077] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 3-9 using HCl and NaOH.

[0078] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 0mT (no magnetic field) or 10mT, and the reaction time is 60min.

[0079] This embodiment tested the U(VI) extraction rate of commercial iron powder with and without a weak magnetic field enhancement at different pH levels. The results are as follows: Figure 7 As shown, after 60 minutes of reaction, at pH 6, the weak magnetic field had the greatest relative promoting effect on iron powder, with an extraction rate of U(VI) 2.16 times that without a magnetic field. However, at pH 5, the iron powder under the enhanced weak magnetic field had the highest extraction rate of uranium, reaching 65%. This is because the main principle behind the enhanced activity of iron powder by the weak magnetic field is that the magnetized iron powder particles guide Fe... 2+ Migration on the surface of iron powder, and more Fe will be generated under acidic conditions. 2+ Therefore, the weak magnetic field in an acidic environment has a stronger promoting effect on the activity of iron powder.

[0080] Example 8

[0081] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0082] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L. Then, (NH4)2SO4, (NH4)2C2O4, NH4Cl, and NH4NO3 are added to make NO3... - SO4 2- Cl - C2O4 2- The concentration was 0.01 mol / L, and the pH of the solution was adjusted to 5 using HCl and NaOH.

[0083] S2. Add 50 ml of fluorine-containing uranium-containing solution to a 100 ml beaker, and then add 25 mg of 1 μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400 r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 10 mT, and the reaction time is 60 min.

[0084] This embodiment investigated the U(VI) extraction rate of commercial iron powder enhanced by a weak magnetic field in the presence of different anions. The results are as follows: Figure 8 As shown. It can be seen that Cl - C2O4 2- The impact on uranium separation efficiency is greatest, with U(VI) extraction rate dropping to 40%, and NO3... - SO4 2- The impact is relatively small.

[0085] Commercial iron powder obtained after uranium separation in Example 4 was collected and characterized by FT-IR, with the original commercial iron powder as a control. The results are as follows: Figure 9 As shown, characteristic peaks of UF, Fe-O, UO, and Fe-OH bonds appeared in the commercial iron powder after the reaction under a weak magnetic field, indicating that the coordination environment of uranium was relatively complex, and that the commercial iron powder was transformed into iron oxide containing abundant oxygen-containing functional groups. Furthermore, the presence of UO and Fe-OH bond signals indicates the formation of iron hydroxide in the commercial iron powder and precipitate, with -OH and UO2... 2+ It has high binding strength, which is beneficial for the adsorption and separation of U(VI).

[0086] The commercial iron powder obtained after uranium separation in Example 4 was characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 10 As shown. Figure 10 (a) is a SEM image of uranium separation from commercial iron powder without weak magnetic field enhancement, showing only slight wrinkles on the surface of the iron powder; Figure 10 (b) is a SEM image of commercial iron powder after uranium separation under a weak magnetic field. The surface morphology of the iron powder underwent drastic changes, forming a fractal structure of a densely arranged array of nanosheets, which greatly increased the uranium separation efficiency of the commercial iron powder. 2+ Adsorption capacity.

[0087] XRD analysis was performed on the commercial iron powder obtained after uranium separation in Example 4, and the results are as follows: Figure 11 As shown, in the absence of a weak magnetic field, the iron powder after the reaction did not show any new characteristic peaks and was almost indistinguishable from the original commercial iron powder. This indicates that the iron powder was not highly oxidized or corroded in the fluorine- and uranium-containing solution in the absence of a magnetic field, and did not form a sufficient amount of iron oxide. In the presence of a weak magnetic field, new characteristic peaks appeared (14.147°, 27.072°, 36.387°, 52.809°, 60.785°). By searching the PDF card using MDIjade6 software, it was found that the phase that matched it best was γ-FeOOH (PDF#73-2326), indicating that the nanosheet array formed on the surface of the iron powder was composed of γ-FeOOH.

[0088] Example 9

[0089] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0090] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 5 using HCl and NaOH.

[0091] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 0mT (no magnetic field) or 10mT, and irradiate the beaker with no light or with a 300W xenon lamp and an AM1.5G filter as the light source, and the reaction time is 60min.

[0092] This embodiment experimentally investigated the U(VI) extraction rate of commercial iron powder enhanced by a weak magnetic field and magneto-optical coupling without an external field. The results are as follows: Figure 12 As shown in the figure, the separation ability of commercial iron powder for U(VI) is significantly improved under magneto-optical coupling. In the first 15 minutes of the reaction, the U(VI) extraction rates of the three methods are almost identical. However, after 15 minutes, the U(VI) extraction rate of commercial iron powder under magneto-optical coupling increases rapidly, reaching 92.7% after 60 minutes. Furthermore, a significant acceleration in the U(VI) extraction rate occurs between 15 and 30 minutes, indicating that γ-FeOOH nanosheets gradually form on the surface of the iron powder after 15 minutes of reaction under a weak magnetic field. Under light irradiation, these γ-FeOOH nanosheets begin to exhibit photocatalytic reduction of U(VI). The comparison of U(VI) extraction rates between magneto-optical coupling and the weak magnetic field alone shows that the γ-FeOOH nanosheets generated under a weak magnetic field do indeed contain a large number of U(VI) adsorption sites. However, due to UO2… 2+ The enrichment of γ-FeOOH on the surface of the nanosheets results in localized electropositivity on the nanosheet surface, which hinders the formation of UO2. 2+ The mass transfer process to γ-FeOOH nanosheets was investigated, and under illumination, U(VI) was reduced to a tetravalent, electronegative species via photogenerated electrons, effectively overcoming the limitations of UO2. 2+ Mass transfer to γ-FeOOH nanosheets is hindered.

[0093] Example 10

[0094] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0095] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F- The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 3-10 using HCl and NaOH.

[0096] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400r / min; place a uniform magnetic field with a magnetic field strength of 10mT around the beaker, and irradiate the beaker with a 300W xenon lamp and an AM1.5G filter as the light source, and the reaction time is 60min.

[0097] This embodiment tested the U(VI) extraction rate of commercial iron powder enhanced by magneto-optical coupling at different pH values, and the results are as follows: Figure 13 As shown, the separation performance of commercial iron powder for U(VI) in acidic environment was significantly improved under magneto-optical coupling enhancement. Within the pH range of 4 to 6, the extraction rate of U(VI) from fluoride- and uranium-containing wastewater by commercial iron powder under magneto-optical coupling remained above 85%, with the highest extraction rate of U(VI) reaching 94.3% at pH 5.

[0098] Example 11

[0099] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0100] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein the U(VI) concentration is 100 mg / L, and the fluoride-uranium molar ratio is 0:1, 6.3:1, 12.5:1, 18.8:1, 25:1, 62.5:1 or 125:1. Adjust the pH of the solution to 5 using HCl and NaOH.

[0101] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400r / min; place a uniform magnetic field with a magnetic field strength of 10mT around the beaker, and irradiate the beaker with a 300W xenon lamp and an AM1.5G filter as the light source, and the reaction time is 60min.

[0102] This embodiment experimentally investigated the U(VI) extraction rate of commercial iron powder enhanced by magneto-optical coupling under different fluorine-uranium molar ratios. The results are as follows: Figure 14 As shown, the extraction rate of U(VI) from magneto-optical coupled commercial iron powder remains above 90% at fluorine-uranium molar ratios ranging from 0:1 to 125:1, with a peak of 97.6% observed at a fluorine-uranium molar ratio of 12.5:1.

[0103] Example 12

[0104] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0105] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein the U(VI) concentration is 50, 100, 150, or 200 mg / L, and the NaF concentration is... - The concentration was 100 mg / L, and the pH of the solution was adjusted to 5 using HCl and NaOH.

[0106] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400r / min; place a uniform magnetic field with a magnetic field strength of 10mT around the beaker, and irradiate the beaker with a 300W xenon lamp and an AM1.5G filter as the light source, and the reaction time is 60min.

[0107] This embodiment investigated the U(VI) extraction rate of commercial iron powder enhanced by magneto-optical coupling under different initial U(VI) concentrations. The results are as follows: Figure 15 As shown in the figure, the extraction rate of U(VI) from commercial iron powder enhanced by magneto-optical coupling reached over 90% after 60 min at different initial U(VI) concentrations. At higher U(VI) concentrations (100 mg / L, 150 mg / L, 200 mg / L), the extraction pattern of U(VI) from commercial iron powder under magneto-optical coupling remained consistent: the extraction rate increased relatively slowly from 0 to 10 min, accelerated from 10 to 20 min, slowed down again from 20 to 30 min, and finally approached adsorption equilibrium after 30 min. However, at a lower U(VI) concentration of 50 mg / L, the extraction rate was extremely slow from 0 to 10 min, gradually increased from 10 to 30 min, and approached adsorption equilibrium.

[0108] Example 13

[0109] A method for enhancing the efficiency of commercial iron powder uranium separation in an outdoor field includes the following steps:

[0110] S1. Prepare simulated fluoride- and uranium-containing wastewater solutions of appropriate concentrations using UO2(NO3)2·6H2O and NaF, wherein F - The concentration of U(VI) is 100 mg / L, and the pH of the solution is adjusted to 5 using HCl and NaOH.

[0111] S2. Add 50ml of fluorine-containing uranium-containing solution to a 100ml beaker, and then add 25mg of 1μm commercial iron powder; place an external mechanical stirrer to continuously stir the reaction at a speed of 400r / min; place a uniform magnetic field around the beaker with a magnetic field strength of 0mT (no magnetic field) or 10mT, and irradiate the beaker with a 300W xenon lamp and an AM1.5G filter as the light source, and the reaction time is 60min.

[0112] The transient photocurrent response of commercial iron powder U(VI) separation experiment under light illumination and magneto-optical coupling without a magnetic field in this embodiment was tested, and the results are as follows: Figure 16 As shown in the figure, the photocurrent of commercial iron powder under illumination only without a magnetic field is 0.223 × 10⁻⁶. -5 A / cm 2 Around 0.326 × 10⁻⁶ Ω·cm, the photocurrent of commercial iron powder under magneto-optical coupling is approximately 0.326 × 10⁻⁶ Ω·cm. -5 A / cm 2 This indicates that in the presence of a magnetic field, γ-FeO OH is rapidly generated on the surface of commercial iron powder, enhancing its photoresponse capability and promoting the reduction of U(VI). Furthermore, the continuously rising current baseline under the magnetic field indicates that the commercial iron powder is rapidly corroded under the magnetic field, spontaneously generating dark current. This confirms the reactivity of the weak magnetic field on the commercial iron powder during the reaction process and its promoting effect on U(VI) separation performance. After the photogenerated electrons are consumed, the remaining holes will be filled by electrons in the iron powder, further accelerating the corrosion of the iron powder and generating more iron oxide products.

[0113] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for enhancing the efficiency of commercial iron powder uranium separation in an external field, characterized in that, The process includes the following steps: adding commercial iron powder to a reactor containing fluorine- and uranium-containing wastewater; and performing uranium separation treatment on the wastewater under the action of an external field and continuous stirring; wherein the external field is magneto-optical coupling; and the concentration of U(VI) in the fluorine- and uranium-containing wastewater is 20~500 mg / L, and F... - The molar ratio with U(VI) is 0~130:1, and the pH value is 3~10; The specific method of the external field effect is as follows: (1) Place a weak magnetic field around or at the bottom of the reactor; the strength of the weak magnetic field is 3~10mT; (2) Based on (1), add an external light source to irradiate the reactor and form magneto-optical coupling; Among them, a weak magnetic field magnetizes commercial iron powder, attracting Fe 2+ Migration disrupts the passivation layer on the surface of iron powder, promoting the reaction of U(VI) with Fe. 0 The redox reaction occurs; the magnetized iron powder particles have a stronger affinity for the paramagnetic molecule O2, resulting in the formation of γ-FeOOH nanosheets with a high specific surface area on the iron powder surface. The γ-FeOOH surface has abundant oxygen-containing functional groups, and the separation of U(VI) is achieved through the bonding of -OH with U(VI).

2. The method for enhancing the separation efficiency of commercial iron powder uranium in an external field as described in claim 1, characterized in that, The commercial iron powder is in the micron range; the amount of commercial iron powder added is 0.5~2.5g / L.

3. The method for enhancing the separation efficiency of commercial iron powder uranium in an external field as described in claim 1, characterized in that, The stirring speed is 300~500 r / min.

4. The method for enhancing the separation efficiency of commercial iron powder uranium in an external field as described in claim 1, characterized in that, The weak magnetic field can be either a uniform magnetic field or a non-uniform magnetic field.

5. The method for enhancing the separation efficiency of commercial iron powder uranium in an external field as described in claim 1, characterized in that, The external light source is a 200-400W xenon lamp equipped with an AM1.5G filter.

Images