A functionalized silica gel adsorption material and its preparation method and application

Abstract

The present invention provides a functionalized silica gel adsorption material, its preparation method, and application, belonging 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; sequentially and uniformly dispersing 3-aminopropyltriethoxysilane and an aqueous solution of ferric chloride in the silica gel dispersion, adding a reducing agent for a reduction reaction, and obtaining a zero-valent iron-functionalized silica gel adsorption material; and uniformly mixing the zero-valent iron-functionalized silica gel adsorption material with phosphoric acid and then ultrasonically treating the mixture to obtain the functionalized silica gel adsorption material. The ultrasound-assisted method of the present invention is simple and has high synthesis efficiency. The prepared adsorption material has the characteristics of rapid adsorption rate, high adsorption capacity, and good cyclic stability.

Description

Technical Field

[0001] The present 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

[0002] Traditional methods for separating radionuclides include chemical precipitation, solvent extraction, membrane separation, ion exchange, and adsorption. In recent years, while various methods have been explored for removing and recovering uranium from nuclear wastewater, adsorption has gained widespread recognition and application due to its economical, efficient, and environmentally friendly advantages.

[0003] Silica gel adsorbents exhibit excellent performance in adsorbing water, gas and organic matter due to their low price, easy availability, high specific surface area and developed pore structure. The hydroxyl groups on the surface of silica gel can form coordination bonds with metal ions to achieve the fixation of 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 groups, 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

[0004] 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.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is a method for preparing a functionalized silica gel adsorption material, comprising the following steps:

[0007] Evenly dispersing silica gel in water to obtain a silica gel dispersion;

[0008] After uniformly dispersing 3-aminopropyltriethoxysilane and an aqueous solution of ferric chloride in the silica gel dispersion, a reducing agent is added to carry out a reduction reaction to obtain a zero-valent iron functionalized silica gel adsorption material;

[0009] 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.

[0010] The second technical solution of the present invention is a functionalized silica gel adsorption material prepared by the above preparation method.

[0011] 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.

[0012] A fourth technical solution of the present invention is a method for removing uranium from wastewater, comprising mixing the functionalized silica gel adsorption material with uranium-containing wastewater to adsorb uranium, and then adding an eluent to the functionalized silica gel adsorption material that has adsorbed uranium to elute the uranium.

[0013] The present invention discloses the following technical effects:

[0014] 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 industrial production.

[0015] The functionalized silica gel adsorbent provided by this invention has a unique affinity for uranyl ions and can be used to rapidly adsorb uranium (VI) from wastewater. When the initial uranium (VI) concentration is less than 20 mg / L, adding 5 mg of the adsorbent to 50 mL of uranium-containing wastewater can adsorb 90% of the uranium (VI) in as little as one minute, with a post-equilibrium removal rate reaching up to 99%.

[0016] The functionalized silica gel prepared by the present invention also has the ability to be recycled. -1 The adsorbent material was eluted with sodium bicarbonate and then dried and recovered. After five cycles of experiments, the prepared adsorbent material still maintained a removal rate of more than 80% for 50 mg / L uranium (VI), showing good cyclic stability and promising application prospects in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. 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 any creative work.

[0018] Figure 1 This is a scanning electron microscope image of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0019] Figure 2 This is the X-ray photoelectron spectroscopy (XPS) of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0020] Figure 3 This is a graph showing the adsorption performance of the materials prepared in Comparative Examples 2-4 for hexavalent uranium (VI).

[0021] Figure 4This is a graph showing the adsorption performance of hexavalent uranium (VI) by the materials prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0022] 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.

[0023] 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.

[0024] Figure 7 This is the adsorption thermodynamic curve of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0025] Figure 8 This is a cycle test performance diagram of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1.

[0026] Figure 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

[0027] 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 rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0029] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice 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 any conflict with any incorporated document, the contents of this specification shall prevail.

[0030] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0031] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0032] Room temperature in the present invention refers to a temperature of 20-35°C.

[0033] The mechanical effects and cavitation of ultrasound can promote intermolecular collisions, thereby accelerating chemical reaction rates. The local high temperature and high pressure environment generated at the interface helps overcome the reaction energy barrier and promote reactions such as chemical grafting modification. The present invention uses ultrasound to assist in the preparation of a silica gel adsorption material synergistically modified with phosphate / zero-valent iron. This method is not only low-cost and environmentally friendly, but also significantly improves the efficiency and capacity of the silica gel adsorbent. It has extremely high practical value and is of great significance in promoting the development of nuclear wastewater treatment technology.

[0034] The present invention presents a silica gel adsorbent material functionalized with phosphoric acid and zero-valent iron, prepared by an ultrasound-assisted method, that effectively removes uranium (VI). This material exhibits rapid adsorption rates and high adsorption capacity. Furthermore, the raw materials required for its preparation are readily available and inexpensive, and the preparation process is simple and efficient. In simulations of high-concentration uranium (VI), the adsorption capacity was high, and good cyclic stability was maintained after five cycles, demonstrating excellent practical applicability.

[0035] The first aspect of the present invention provides a method for preparing a functionalized silica gel adsorption material, comprising the following steps:

[0036] Evenly dispersing silica gel in water to obtain a silica gel dispersion;

[0037] 3-aminopropyltriethoxysilane (APTES) and an aqueous solution of ferric chloride are uniformly dispersed in the silica gel dispersion in sequence, and then a reducing agent is added to perform a reduction reaction to obtain a zero-valent iron functionalized silica gel adsorption material;

[0038] 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.

[0039] The present invention does not impose any particular limitation on the dispersing method for uniformly dispersing silica gel in water and uniformly dispersing 3-aminopropyltriethoxysilane and ferric chloride aqueous solution in the silica gel dispersion in sequence. Conventional technical means of those skilled in the art may be used, such as stirring dispersion and ultrasonic dispersion.

[0040] 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 ~3 mol·L -1 , preferably 1 mol·L -1 .

[0041] In some embodiments of the present invention, the reducing agent is sodium borohydride; and the mass ratio of the sodium borohydride to the silica gel is 0.85:(0.2-2).

[0042] In some embodiments of the present invention, the reduction reaction temperature is room temperature and the time is 5-6 hours.

[0043] 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.

[0044] 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 further included.

[0045] In some embodiments of the present invention, the amount of the phosphoric acid solution is 200-300 mL of concentrated phosphoric acid.

[0046] In some embodiments of the present invention, the ultrasonic treatment parameters are set as: 700-800w power ultrasound at room temperature for 5-8h.

[0047] In some embodiments of the present invention, after the ultrasonic treatment is completed, the steps of centrifuging the obtained reaction solution to collect the solid product, and then washing and drying the obtained solid product are further included.

[0048] The second aspect of the present invention provides a functionalized silica gel adsorption material prepared by the above preparation method.

[0049] A third aspect of the present invention provides a use of the above-mentioned functionalized silica gel adsorption material in adsorbing uranium in wastewater.

[0050] A fourth aspect of the present invention provides a method for removing uranium from wastewater, comprising mixing the functionalized silica gel adsorption material with uranium-containing wastewater to adsorb uranium (VI), and then adding an eluent to the functionalized silica gel adsorption material that has adsorbed uranium to elute the uranium.

[0051] 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 adsorption material to the uranium-containing wastewater is 0.2 g / L; and the eluent is sodium bicarbonate.

[0052] In some embodiments of the present invention, when the functionalized silica gel adsorption material is mixed with uranium-containing wastewater to adsorb uranium (VI), the temperature of the reaction system is 20-40°C.

[0053] In some embodiments of the present invention, the concentration of uranium in the uranium-containing wastewater is 10 ppm-150 ppm.

[0054] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0055] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

[0056] The concentrated phosphoric acid in the examples is undiluted commercially available concentrated phosphoric acid.

[0057] Example 1

[0058] A method for preparing a phosphoric acid / zero-valent iron functionalized silica gel adsorption material, comprising the following steps:

[0059] (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 dispersed evenly by ultrasonication for 15 min, and then magnetically stirred to obtain a silica gel aqueous solution. 0.325 g of ferric chloride hydrate and 20 mL of deionized water were added to a beaker, and the ferric chloride was dispersed evenly by ultrasonication for 15 min, and then magnetically stirred at 40 °C to obtain a 1 mol·L -1 Ferric chloride aqueous solution.

[0060] (2) Take 0.1 mL of 3-aminopropyltriethoxysilane (APTES) and add it to the magnetically stirred silica gel aqueous solution in step (1). Continue stirring at 40°C for 15 minutes to fully mix it. Then use a rubber-tipped dropper to add 20 mL of the prepared 1 mol·L -1 The ferric chloride aqueous solution was slowly added dropwise into the silica gel aqueous solution beaker, and then magnetically stirred at 40°C for 2 hours to fully mix.

[0061] (3) Weigh 0.85g of sodium borohydride, add the weighed sodium borohydride and deionized water to a beaker, and use ultrasonic assistance for 15 minutes to fully dissolve the sodium borohydride. Transfer the mixed solution obtained in step (2) to a three-necked flask and continue magnetic stirring at room temperature. Nitrogen is introduced as a protective gas. Sodium borohydride is used as a reducing agent. 20mL of freshly prepared sodium borohydride solution is slowly added to 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 left 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 in the 2 / 3 volume of the centrifuge tube symmetrically in a centrifuge and centrifuge at 8000rpm 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 centrifugation steps 3 times; after centrifugation, wash with deionized water and anhydrous ethanol alternately 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.

[0062] (4) The zero-valent iron functionalized silica gel adsorption material obtained in step (3) and 250 mL of concentrated phosphoric acid were added to a beaker and magnetically stirred at room temperature for 1 hour to fully mix. The mixed solution was then subjected to ultrasonic treatment at 800 W power for 6 hours under the assistance of an ultrasonic field. The reaction solution was then poured into a centrifuge tube, and deionized water was added to 2 / 3 of the volume of the centrifuge tube. The solution of 2 / 3 of the volume of the centrifuge tube was placed in an equal amount in a centrifuge and centrifuged at 8000 rpm for 5 minutes. After the centrifugation was completed, the supernatant was poured out and deionized water was added to 2 / 3 of the volume of the centrifuge tube. The centrifugation was continued and the above steps were repeated until the pH of the supernatant was neutral. The product after centrifugation was collected and washed alternately with deionized water and anhydrous ethanol three times. Finally, the product was transferred to a freeze dryer and dried for 12 hours to obtain a phosphoric acid / zero-valent iron functionalized silica gel adsorption material.

[0063] Comparative Example 1

[0064] The preparation method of phosphoric acid functionalized silica gel adsorption material comprises the following steps:

[0065] (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. Then, a silica gel aqueous solution was obtained by magnetic stirring at room temperature.

[0066] (2) Add 250 mL of concentrated phosphoric acid to a beaker of silica gel aqueous solution and continue magnetic stirring at room temperature for 1 hour to fully mix it. Then, treat the mixed solution with ultrasound at 800 W power for 6 hours under the assistance of an ultrasonic field. Pour the reaction solution into a centrifuge tube, and then add deionized water to 2 / 3 of the volume of the centrifuge tube; place equal amounts of the solution with 2 / 3 of the volume of the centrifuge tube symmetrically in a centrifuge and centrifuge 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)

[0067] Comparative Example 2

[0068] The only difference from Example 1 is that step (4) is omitted, and the remaining steps and parameters are the same as Example 1. A zero-valent iron functionalized silica gel adsorption material is obtained (ie, the difference from Example 1 is that the silica gel is not functionalized with phosphoric acid).

[0069] Comparative Example 3

[0070] 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 remaining steps and parameters are the same as those in Comparative Example 2.

[0071] Comparative Example 4

[0072] 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 remaining steps and parameters are the same as those in Comparative Example 2.

[0073] Figure 1 This is a scanning electron micrograph of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1. As can be seen, the prepared phosphate / zero-valent iron functionalized silica gel has a well-defined microstructure, exhibiting a hexagonal structure and a rough surface. This high specific surface area facilitates the exposure of active sites during uranium adsorption.

[0074] 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 2The complete XPS spectrum of the phosphate / zero-valent iron functionalized adsorption material shows 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 have been introduced into the silica gel.

[0075] Figure 3 、 4 This is a graph showing the change in uranium adsorption capacity of the functionalized silica gel adsorption materials prepared in Example 1 and Comparative Examples 1-4 over time. A certain amount of UO2(NO3)2·6H2O was dissolved in deionized water to prepare a U(VI) solution (50 mg / L), and the pH value of the solution was 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 was adjusted to 6). For each experiment, 5 mg of adsorption material was weighed and added to a centrifuge tube containing 25 mL of 50 mg / L uranium solution. The centrifuge tube was placed in a shaker, and samples were taken at time intervals of 1 min, 3 min, 5 min, 10 min, 30 min and 60 min, and the concentration of uranium ions in the solution before and after adsorption was determined by ultraviolet spectrophotometry. Figure 3 It can be seen that the zero-valent iron functionalized silica gel adsorption materials prepared in Comparative Examples 2-4 all have a certain adsorption effect, but the effect of Comparative Example 2 is the best. A 90% removal rate 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 step 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 effects of the materials in Comparative Examples 1 and 2, Example 1 has the largest adsorption capacity, indicating that the prepared phosphate / zero-valent iron functionalized silica gel adsorption material has excellent adsorption performance, and phosphoric acid and zero-valent iron have a synergistic effect on the adsorption of uranium.

[0076] Figure 5 The uranium adsorption capacity of the phosphate / zero-valent iron functionalized silica gel adsorption material prepared in Example 1 at different pH conditions (the pH value of the solution was adjusted by nitric acid or sodium hydroxide solution to change the range from 2 to 8). Each time, 5 mg of fixed sample was taken, 25 mL of liquid was transferred to a centrifuge tube, and the centrifuge tube was placed in a constant temperature shaker and shaken for 2 hours. Figure 5 It can be seen that when the pH of the solution is between 2 and 6, the adsorption capacity of the adsorption material prepared in Example 1 continues to increase and reaches a peak at 6. When the pH is greater than 6, the adsorption capacity decreases slightly but still maintains relatively good performance. It can be seen that the material of the present invention has good acid and alkali resistance.

[0077] Figure 6The phosphate / zero-valent iron functionalized silica gel adsorbent prepared in Example 1 was used to extract uranium in U(VI) solutions of varying initial concentrations. A fixed 5 mg sample was taken at each time, and 25 mL of the solution was pipetted into a centrifuge tube. The tube was then shaken for 2 hours. When the uranium solution concentration was between 10 and 150 mg / L, the adsorption capacity of the phosphate / zero-valent iron functionalized silica gel adsorbent increased continuously with increasing uranium solution concentration, gradually reaching saturation, with a maximum adsorption capacity of 480 mg / g.

[0078] Figure 7 This graph shows the uranium adsorption capacity of the phosphate / zero-valent iron functionalized silica gel adsorbent prepared in Example 1 at different temperatures. A fixed 5 mg sample was taken at each time, and 25 mL of a 50 mg / L uranium solution was pipetted into a centrifuge tube, which was then shaken for 2 hours. Tests were conducted at 293.15 K, 298.15 K, 303.15 K, 308.15 K, and 313.15 K. As shown in the graph, the equilibrium uranium adsorption capacity of the adsorbent in Example 1 increases with increasing temperature, indicating, to some extent, that the adsorption process is endothermic.

[0079] Figure 8 This graph shows the adsorption capacity of the phosphate / zero-valent iron-functionalized silica gel adsorbent prepared in Example 1 after five consecutive cycles. Sodium bicarbonate was used as the eluent for uranium elution. The graph shows that after five cycles of uranium adsorption and desorption, the adsorption performance of the adsorbent in Example 1 only slightly decreased, maintaining an 80% removal rate.

[0080] Figure 9 As shown in Figure 2, the phosphate / zero-valent iron functionalized silica gel adsorption material is not affected by the coexistence of 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 the phosphate / zero-valent iron functionalized silica gel adsorption material, thereby reducing the active sites available for capturing U(VI). 3- 、Cl - The effect on U(VI) adsorption is small. 2- The presence of CO3 leads to a decrease in the adsorption rate of phosphate / zero-valent iron functionalized silica gel adsorption material. This is because CO3 2- and UO2 2+ The coexistence of can form complexes that are difficult to adsorb,

[0081] 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 principles of the present invention. These improvements and modifications should also be regarded as within 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 uniformly dispersing 3-aminopropyltriethoxysilane and an aqueous solution of ferric chloride in the silica gel dispersion, 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 concentrated phosphoric acid are uniformly mixed and then ultrasonically treated to obtain the functionalized silica gel adsorption material.

2. The method for preparing a functionalized silica gel adsorption material according to claim 1, wherein: 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 ~3 mol·L -1 ; The amount of concentrated phosphoric acid is 200-300mL.

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

5. The method for preparing a functionalized silica gel adsorption material according to claim 1, wherein: The ultrasonic treatment parameters were set as follows: 700-800w ultrasonic power at room temperature for 5-8 hours.

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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