Functionalized silica gel adsorption material as well as preparation method and application thereof

Abstract

The invention provides a functionalized silica gel adsorption material as well as a preparation method and application thereof, and belongs to the technical field of adsorption material preparation. The method comprises the following steps: uniformly dispersing silica gel in water to obtain a silica gel dispersion liquid; 3-aminopropyltriethoxysilane and a ferric chloride aqueous solution are sequentially and uniformly dispersed in the silica gel dispersion liquid, a reducing agent is added for a reduction reaction, and the zero-valent iron functionalized silica gel adsorption material is obtained; and uniformly mixing the zero-valent iron functionalized silica gel adsorption material and phosphoric acid, and performing ultrasonic treatment to obtain the functionalized silica gel adsorption material. The ultrasonic-assisted method is simple and convenient, the synthesis efficiency is high, and the prepared adsorption material has the characteristics of high adsorption rate, high adsorption capacity and good cycle stability.

Description

Technical Field

[0001] The invention relates to the technical field of adsorption material preparation, and in particular to a functionalized silica gel adsorption material and a preparation method and application thereof. Background Art

[0003] Traditional methods for separating radionuclides include chemical precipitation, solvent extraction, membrane separation, ion exchange, and adsorption. In recent years, although various methods have been tried to remove and recover uranium from nuclear wastewater, the adsorption method has won wide recognition and application due to its economic, high-efficiency, and environmentally friendly advantages.

[0004] Silica gel adsorbents are inexpensive, easy to obtain, and have a high specific surface area and a developed pore structure, so they show excellent performance in adsorbing water, gas and organic matter. The hydroxyl groups on the surface of silica gel can form coordination bonds with metal ions to fix the metal ions, and are widely used in wastewater treatment and metal recovery. However, the adsorption capacity of native silica gel for uranium is limited, and its adsorption performance needs to be improved through modification. This usually involves introducing functional groups (such as amino, carboxyl, sulfonic acid, etc.) on the surface of silica gel to enhance its selective adsorption of specific molecules. This process is mostly achieved through chemical reactions such as chemical deposition or covalent bonding. In addition, the combination of silica gel with other materials (such as activated carbon, metal oxides or polymers) can also significantly improve its adsorption performance and achieve more efficient separation and purification effects. However, current silica gel adsorbents still have problems such as slow adsorption rate and insufficient adsorption capacity. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a functionalized silica gel adsorption material and a preparation method and application thereof.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is a method for preparing a functionalized silica gel adsorption material, comprising the following steps:

[0008] Evenly dispersing silica gel in water to obtain a silica gel dispersion;

[0009] After 3-aminopropyltriethoxysilane and ferric chloride aqueous solution are uniformly dispersed in the silica gel dispersion in sequence, a reducing agent is added to carry out a reduction reaction to obtain a zero-valent iron functionalized silica gel adsorption material;

[0010] The zero-valent iron functionalized silica gel adsorption material and phosphoric acid are uniformly mixed and then subjected to ultrasonic treatment to obtain the functionalized silica gel adsorption material.

[0011] The second technical solution of the present invention is a functionalized silica gel adsorption material prepared by the above preparation method.

[0012] A third technical solution of the present invention is an application of the above-mentioned functionalized silica gel adsorption material in adsorbing uranium in wastewater.

[0013] A fourth technical solution of the present invention is a method for removing uranium from wastewater, comprising mixing the above-mentioned functionalized silica gel adsorption material with uranium-containing wastewater to adsorb uranium, and then adding an eluent to the functionalized silica gel adsorption material adsorbing uranium for elution.

[0014] The present invention discloses the following technical effects:

[0015] The functionalized silica gel adsorption material provided by the present invention has a simple preparation process, uses low-cost materials, and can be easily promoted to realize industrialized production.

[0016] The functionalized silica gel adsorbent provided by the present invention has a unique affinity for uranyl ions and can be used to quickly adsorb uranium (VI) in wastewater. When the initial concentration of uranium (VI) is less than 20 mg / L, 5 mg of the adsorbent product is added to 50 mL of uranium-containing wastewater, and 90% of uranium (VI) can be adsorbed in as fast as 1 minute, and the removal rate after equilibrium can reach 99% at best.

[0017] The functionalized silica gel prepared by the present invention also has the performance of recycling. -1 The adsorbent material was eluted with sodium bicarbonate and then dried and recovered. After 5 cycles of experiments, the removal rate of the prepared adsorbent material for 50 mg / L uranium (VI) was still maintained at more than 80%, with good cycle stability and good application prospects in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a scanning electron microscope image of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0020] Figure 2 This is the X-ray photoelectron spectrum (XPS) of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0021] Figure 3 This is a graph showing the adsorption performance of the materials prepared in Comparative Examples 2-4 for hexavalent uranium (VI).

[0022] Figure 4This is a graph showing the adsorption performance of the materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 for hexavalent uranium (VI).

[0023] Figure 5 This is the adsorption isotherm of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1 at different pH values.

[0024] Figure 6 This is the adsorption curve of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1 in U(VI) solutions with different initial concentrations.

[0025] Figure 7 This is the adsorption thermodynamic curve of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0026] Figure 8 This is a cyclic test performance diagram of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0027] Fig. 9 This is a diagram of the ion competition experiment of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0033] Room temperature in the present invention refers to a temperature of 20-35°C.

[0034] The mechanical effect and cavitation of ultrasound can promote collisions between molecules, thereby accelerating the rate of chemical reactions. The local high temperature and high pressure environment generated at the interface helps to overcome the reaction energy barrier and promote reactions such as chemical grafting modification. The present invention prepares silica gel adsorption materials synergistically modified with phosphate / zero-valent iron by ultrasound assistance. This method is not only low-cost and environmentally friendly, but also significantly improves the efficiency and capacity of silica gel adsorbents, has extremely high practical value, and is of great significance to promoting the development of nuclear wastewater treatment technology.

[0035] The silica gel adsorption material functionalized with phosphoric acid and zero-valent iron prepared by the ultrasound-assisted method can effectively remove uranium (VI). The material has the characteristics of fast adsorption rate and high adsorption capacity, and the raw materials required for preparing the adsorption material are cheap and easy to obtain, and the preparation process is simple and the synthesis efficiency is high. In the simulation experiment of high-concentration uranium (VI), the adsorption capacity is high, and good cycle stability is maintained after 5 cycles, which has excellent practical applicability.

[0036] The first aspect of the present invention provides a method for preparing a functionalized silica gel adsorption material, comprising the following steps:

[0037] Evenly dispersing silica gel in water to obtain a silica gel dispersion;

[0038] After 3-aminopropyltriethoxysilane (APTES) and ferric chloride aqueous solution are uniformly dispersed in the silica gel dispersion in sequence, a reducing agent is added to perform a reduction reaction to obtain a zero-valent iron functionalized silica gel adsorption material;

[0039] The zero-valent iron functionalized silica gel adsorption material and phosphoric acid are uniformly mixed and then subjected to ultrasonic treatment to obtain the functionalized silica gel adsorption material.

[0040] The present invention does not specifically limit the dispersing method of uniformly dispersing silica gel in water and uniformly dispersing 3-aminopropyltriethoxysilane and ferric chloride aqueous solution in the silica gel dispersion in sequence, and conventional technical means of those skilled in the art may be used, such as stirring dispersion and ultrasonic dispersion.

[0041] In some embodiments of the present invention, the mass volume ratio of the silica gel, 3-aminopropyltriethoxysilane and ferric chloride aqueous solution is 0.2-2 g: 0.1-0.5 mL: 20 mL; the concentration of the ferric chloride aqueous solution is 1 mol·L -1 ~3mol·L -1 , preferably 1 mol·L -1 .

[0042] In some embodiments of the present invention, the reducing agent is sodium borohydride; the mass ratio of the sodium borohydride to the silica gel is 0.85:(0.2-2).

[0043] In some embodiments of the present invention, the reduction reaction is carried out at room temperature for 5-6 hours.

[0044] In some embodiments of the present invention, the reaction atmosphere for carrying out the reduction reaction is an inert protective gas atmosphere; the inert protective gas is preferably nitrogen.

[0045] In some embodiments of the present invention, after the reduction reaction is completed, the steps of centrifuging the obtained reaction solution, collecting the solid product, and sequentially washing and drying the solid product are also included.

[0046] In some embodiments of the present invention, the amount of the phosphoric acid solution is 200-300 mL of concentrated phosphoric acid.

[0047] In some embodiments of the present invention, the ultrasonic treatment parameters are set as: 700-800w power ultrasound for 5-8h at room temperature.

[0048] In some embodiments of the present invention, after the ultrasonic treatment is completed, the steps of centrifuging the obtained reaction solution, collecting the solid product, and washing and drying the obtained solid product are further included.

[0049] The second aspect of the present invention provides a functionalized silica gel adsorption material prepared by the above preparation method.

[0050] The third aspect of the present invention provides an application of the above functionalized silica gel adsorption material in adsorbing uranium in wastewater.

[0051] The fourth aspect of the present invention provides a method for removing uranium from wastewater, wherein the functionalized silica gel adsorption material is mixed with uranium-containing wastewater to adsorb uranium (VI), and then an eluent is added to the functionalized silica gel adsorption material adsorbing uranium for elution.

[0052] In some embodiments of the present invention, the pH value of the uranium-containing wastewater is 2 - 8 (more preferably, pH = 6); the solid-liquid ratio of the functionalized silica gel adsorbent material to the uranium-containing wastewater is 0.2 g / L; the eluent is sodium bicarbonate.

[0053] In some embodiments of the present invention, when the functionalized silica gel adsorbent material is mixed with the uranium-containing wastewater for the adsorption of uranium (VI), the temperature of the reaction system is 20 - 40 °C.

[0054] In some embodiments of the present invention, the concentration of uranium in the uranium-containing wastewater is 10 ppm - 150 ppm.

[0055] The technical solutions of the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are all purchased from commercial channels or are publicly available.

[0056] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with examples, but the content of the present invention is not limited to the following examples.

[0057] The concentrated phosphoric acid in the examples is commercially available concentrated phosphoric acid without dilution.

[0058] Example 1

[0059] A preparation method of a phosphoric acid / zero-valent iron functionalized silica gel adsorbent material is as follows:

[0060] (1) Add 0.8 g of silica gel powder and 250 mL of deionized water into a beaker, use ultrasonic assistance for 15 min to disperse the silica gel powder evenly, and then obtain a silica gel aqueous solution through magnetic stirring. Add 0.325 g of ferric chloride hydrate and 20 mL of deionized water into a beaker, use ultrasonic assistance for 15 min until the ferric chloride is dispersed evenly, and then obtain a 1 mol·L -1 ferric chloride aqueous solution at 40 °C through magnetic stirring.

[0061] (2) Take 0.1 mL of 3-aminopropyltriethoxysilane (APTES) and add it to the magnetically stirred silica gel aqueous solution in step (1), continue to stir at 40 °C for 15 minutes to mix it evenly. Then use a dropper to slowly add the prepared 20 mL of 1 mol·L -1 ferric chloride aqueous solution into the beaker of the silica gel aqueous solution, and then magnetically stir at 40 °C for 2 h to mix it evenly.

[0062] (3) Weigh 0.85g of sodium borohydride, add the weighed sodium borohydride and deionized water into a beaker, and use ultrasonic assistance for 15 minutes to fully dissolve the sodium borohydride. Transfer the mixed solution obtained in step (2) into a three-necked flask and continue magnetic stirring at room temperature, introduce nitrogen as a protective gas, use sodium borohydride as a reducing agent, and slowly add 20mL of freshly prepared sodium borohydride solution into the three-necked flask using a syringe. After 5 hours, a black zero-valent iron product is synthesized. Pour out the supernatant of the reaction solution, and then pour the black precipitate remaining in the three-necked flask into a centrifuge tube, and then add deionized water to 2 / 3 of the volume of the centrifuge tube; place an equal amount of the solution of 2 / 3 volume of the centrifuge tube symmetrically in a centrifuge, centrifuge at 8000rpm for 5 minutes, pour out the supernatant and add deionized water to the centrifuge tube to 2 / 3 volume of the centrifuge tube, continue centrifugation, and repeat the above centrifugation steps 3 times; after centrifugation, wash alternately with deionized water and anhydrous ethanol three times. Finally, the black solid product zero-valent iron was transferred to a freeze dryer and dried for 12 hours to obtain a zero-valent iron functionalized silica gel adsorption material.

[0063] (4) The zero-valent iron functionalized silica gel adsorption material obtained in step (3) and 250 mL of concentrated phosphoric acid are added to a beaker and magnetically stirred at room temperature for 1 hour to fully mix. The mixed solution is then treated with ultrasound at 800 W power for 6 hours under the assistance of an ultrasonic field, and then the reaction solution is poured into a centrifuge tube, and then deionized water is added to 2 / 3 of the volume of the centrifuge tube; 2 / 3 of the volume of the centrifuge tube is placed in an equal amount in a centrifuge, and centrifuged at 8000 rpm for 5 minutes. After the centrifugation is completed, the supernatant is poured out and deionized water is added to the centrifuge tube to 2 / 3 of the volume of the centrifuge tube, and the centrifugation is continued. The above steps are repeated until the pH of the supernatant is neutral; the product after centrifugation is collected, and it is washed alternately with deionized water and anhydrous ethanol three times. Finally, the product is transferred to a freeze dryer and dried for 12 hours to obtain a phosphoric acid / zero-valent iron functionalized silica gel adsorption material.

[0064] Comparative Example 1

[0065] The preparation method of phosphoric acid functionalized silica gel adsorption material comprises the following steps:

[0066] (1) 0.8 g of silica gel powder and 250 mL of deionized water were added to a beaker, and the silica gel powder was evenly dispersed using ultrasonic assistance for 15 min, followed by magnetic stirring at room temperature to obtain a silica gel aqueous solution.

[0067] (2) Add 250 mL of concentrated phosphoric acid to a beaker of silica gel aqueous solution and continue to stir magnetically for 1 hour at room temperature to fully mix. Subsequently, the mixed solution is treated with ultrasound at 800 W power for 6 hours under the assistance of an ultrasonic field, the reaction solution is poured into a centrifuge tube, and then deionized water is added to 2 / 3 of the volume of the centrifuge tube; 2 / 3 of the volume of the centrifuge tube is placed in equal amounts in a centrifuge and centrifuged at 8000 rpm for 5 minutes. After the centrifugation is completed, pour out the supernatant and add deionized water to the centrifuge tube to 2 / 3 of the volume of the centrifuge tube, continue centrifugation, and repeat the above steps until the pH of the supernatant is neutral; collect the product after centrifugation, wash it alternately with deionized water and anhydrous ethanol three times, and finally transfer the product to a freeze dryer and dry it for 12 hours to obtain a phosphoric acid functionalized silica gel adsorption material. (That is, the difference from Example 1 is that the silica gel is not functionalized with zero-valent iron)

[0068] Comparative Example 2

[0069] The only difference from Example 1 is that step (4) is omitted, and the remaining steps and parameters are the same as those of Example 1. A zero-valent iron functionalized silica gel adsorption material is obtained (that is, the difference from Example 1 is that the silica gel is not functionalized with phosphoric acid).

[0070] Comparative Example 3

[0071] The only difference from Comparative Example 2 is that 1 mol·L -1 The ferric chloride aqueous solution was replaced with 2 mol·L -1 The ferric chloride aqueous solution and the other steps and parameters are the same as those in Comparative Example 2.

[0072] Comparative Example 4

[0073] The only difference from Comparative Example 2 is that 1 mol·L -1 The ferric chloride aqueous solution was replaced with 3 mol·L -1 The ferric chloride aqueous solution and the other steps and parameters are the same as those in Comparative Example 2.

[0074] Figure 1 This is a scanning electron microscope image of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1. It can be seen that the prepared phosphate / zero-valent iron functionalized silica gel has a very good microstructure, a hexagonal structure, a rough surface, and a very good specific surface area at the microscopic level, which is beneficial to the exposure of active sites in the uranium adsorption process.

[0075] XPS was used to further study the chemical structure of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1. Figure 2This is a complete XPS spectrum of the phosphate / zero-valent iron functionalized adsorption material. It can be seen from the figure that in Example 1, characteristic peaks of Fe2p and P2p orbitals appear at 713.2 eV and 134.4 eV, indicating that zero-valent iron and phosphate groups may be introduced into the silica gel.

[0076] Figure 3 , 4 The graph of the uranium adsorption capacity of the functionalized silica gel adsorption materials prepared in Example 1 and Comparative Examples 1-4 changes over time. 2 (NO 3 ) 2 6H 2 O is dissolved in deionized water to prepare a U(VI) solution (50 mg / L), and the pH value of the solution is adjusted to about 6.0 with nitric acid or sodium hydroxide solution (unless otherwise specified, the pH value of the U(VI) solution in all experiments is adjusted to 6). For each experiment, 5 mg of adsorbent material is weighed and added to a centrifuge tube containing 25 mL of 50 mg / L uranium solution. The centrifuge tube is placed in a shaker, and samples are taken at time intervals of 1 min, 3 min, 5 min, 10 min, 30 min and 60 min. The concentration of uranium ions in the solution before and after adsorption is determined by ultraviolet spectrophotometry. Figure 3 It can be seen that the zero-valent iron functionalized silica gel adsorption materials prepared in Examples 2-4 all have a certain adsorption effect, but the effect of Example 2 is the best. A removal rate of 90% can be achieved in 1 minute, and adsorption equilibrium can be reached in 5 minutes. This shows that the optimal concentration of the ferric chloride aqueous solution in the preparation of the zero-valent iron functionalized silica gel adsorption material is 1 mol·L -1 This may be because when the concentration of ferric chloride solution is high, the zero-valent iron generated by reduction will agglomerate and affect the adsorption performance. Figure 4 It can be seen that compared with the adsorption effect of the materials in Comparative Examples 1 and 2, it can be seen that the adsorption capacity of Example 1 is the largest, indicating that the prepared phosphate / zero-valent iron functionalized silica gel adsorption material has excellent adsorption performance, and phosphoric acid and zero-valent iron play a synergistic role in the adsorption of uranium.

[0077] Figure 5 The uranium adsorption capacity of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1 under different pH conditions (the pH value of the solution is adjusted by nitric acid or sodium hydroxide solution to change the range of 2-8). Each time, 5 mg of fixed sample is taken, 25 mL of liquid is transferred into a centrifuge tube, and the centrifuge tube is placed in a constant temperature shaker for 2 hours. Figure 5 It can be seen that when the solution pH is between 2 and 6, the adsorption capacity of the adsorption material prepared in Example 1 continues to increase and reaches a peak value at 6. When the pH is greater than 6, the adsorption capacity decreases slightly but still maintains a relatively good performance. It can be seen that the material of the present invention has good acid and alkali resistance.

[0078] Figure 6 The phosphoric acid / zero-valent iron functionalized silica gel adsorbent prepared in Example 1 was subjected to uranium extraction experiments in U(VI) solutions of different initial concentrations. Each time, 5 mg of fixed sample was taken, 25 mL of liquid was transferred into a centrifuge tube, and the centrifuge tube was placed in a shaker for 2 hours. When the uranium solution concentration was in the range of 10-150 mg / L, the adsorption capacity of the phosphoric acid / zero-valent iron functionalized silica gel adsorbent material increased continuously with the increase of the uranium solution concentration and gradually reached saturation, and the maximum adsorption capacity could reach 480 mg / g.

[0079] Figure 7 The uranium adsorption capacity change diagram of the phosphate / zero-valent iron functionalized silica gel adsorbent material prepared in Example 1 at different temperatures. A fixed sample of 5 mg is taken each time, and 25 mL of 50 mg / L uranium solution is pipetted into a centrifuge tube, and the centrifuge tube is placed in a shaker for 2 hours. The temperature was adjusted to 293.15K, 298.15K, 303.15K, 308.15K and 313.15K for testing. It can be seen from the figure that as the temperature increases, the equilibrium adsorption capacity of the adsorbent material of Example 1 for uranium continues to increase, which to a certain extent indicates that the adsorption process is an endothermic process.

[0080] Figure 8 This is a graph of the adsorption capacity of the phosphate / zero-valent iron functionalized silica gel adsorbent prepared in Example 1 after five consecutive cycles. Sodium bicarbonate was selected as the eluent to elute uranium. It can be seen from the graph that after five repeated cycles of uranium adsorption and desorption, the adsorption performance of the adsorbent in Example 1 only slightly decreased, and the removal rate was still maintained at 80%.

[0081] Fig. 9 As shown in the figure, the phosphate / zero-valent iron functionalized silica gel adsorption material is not affected by the coexisting monovalent cations, and the removal efficiency of uranium remains above 90%. However, the presence of divalent cations slightly inhibits the adsorption efficiency of uranium. This phenomenon can be explained by the following reasons: First, Mg 2+ and Ca 2+ Divalent cations such as NO preferentially occupy the adsorption sites on the surface of phosphate / zero-valent iron functionalized silica gel adsorbents, thereby reducing the active sites available for capturing U(VI). 3- , Cl - The effect on U(VI) adsorption is small. 3 2- The presence of CO leads to a decrease in the adsorption rate of the phosphate / zero-valent iron functionalized silica gel adsorption material. This is because CO 3 2- and UO 2 2+ The coexistence of can form complexes that are difficult to adsorb.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a functionalized silica gel adsorption material, characterized in that: The following steps are involved: Evenly dispersing silica gel in water to obtain a silica gel dispersion; After 3-aminopropyltriethoxysilane and ferric chloride aqueous solution are uniformly dispersed in the silica gel dispersion in sequence, a reducing agent is added to carry out a reduction reaction to obtain a zero-valent iron functionalized silica gel adsorption material; The zero-valent iron functionalized silica gel adsorption material and phosphoric acid are uniformly mixed and then subjected to ultrasonic treatment to obtain the functionalized silica gel adsorption material.

2. The method for preparing the functionalized silica gel adsorption material according to claim 1, characterized in that: The mass volume ratio of the silica gel, 3-aminopropyltriethoxysilane and ferric chloride aqueous solution is 0.2-2 g: 0.1-0.5 mL: 20 mL; the concentration of the ferric chloride aqueous solution is 1 mol·L -1 ~3mol·L -1 ; The amount of the phosphoric acid solution is 200-300mL concentrated phosphoric acid.

3. The method for preparing the functionalized silica gel adsorption material according to claim 1, characterized in that: The reducing agent is sodium borohydride; the mass ratio of the sodium borohydride to the silica gel is 0.85:(0.2-2).

4. The method for preparing a functionalized silica gel adsorption material according to claim 1, characterized in that: The temperature of the reduction reaction is room temperature and the time is 5-6 hours.

5. The method for preparing the functionalized silica gel adsorption material according to claim 1, characterized in that: The ultrasonic treatment parameters are set as: 700-800w power ultrasound for 5-8h at room temperature.

6. A functionalized silica gel adsorption material prepared according to the preparation method according to any one of claims 1 to 5.

7. Use of the functionalized silica gel adsorption material according to claim 6 in adsorbing uranium in wastewater.

8. A method for removing uranium from wastewater, characterized in that: The functionalized silica gel adsorption material according to claim 7 is mixed with uranium-containing wastewater to adsorb uranium, and then an eluent is added to the functionalized silica gel adsorption material adsorbing uranium to elute it.

9. The method for removing uranium from wastewater according to claim 8, characterized in that: The pH value of the uranium-containing wastewater is 2-8; the solid-liquid ratio of the functionalized silica gel adsorption material to the uranium-containing wastewater is 0.2 g / L; and the eluent is sodium bicarbonate.

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