A method for preparing amidoximated hollow mesoporous motor adsorbent based on hard template method and its application in uranium extraction

Abstract

The present invention discloses a method for preparing amidoximated hollow mesoporous motor adsorbent based on a hard template method and its application in uranium extraction. First, polydopamine-coated polystyrene particles PS@PDA are synthesized. After in-situ reduction modification of Au nanoparticles on the surface of polydopamine PDA, a silicon layer is coated. Subsequently, the PS@PDA template is removed by calcination at 500°C to prepare a matrix material SiO2∩Au with a photothermal drive effect. Finally, a mesoporous silicon layer with cyanide C≡N is coated on the surface of SiO2∩Au by a co-condensation method. After adding NH2OH·HCl, C≡N is reduced to AO functional group to prepare the hollow mesoporous motor adsorbent MSSA-AO, which is used for the adsorption and separation of UO2 2+ MSSA‑AO has excellent adsorption selectivity and regeneration performance, and has great application potential in the field of uranium extraction from seawater.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of functional materials for adsorption and separation, and relates to a method for preparing a hollow mesoporous nano-adsorbent suitable for selectively and efficiently enriching uranium (U(VI)) in seawater, and in particular to a method for preparing a photothermally driven amidoximated hollow mesoporous motor adsorbent based on a hard template method, and its application in the field of U(VI) extraction in seawater. Background Art

[0002] Nuclear energy, as a clean energy source, is an important guarantee for achieving sustainable development. As the most important fuel for nuclear power operations, uranium resources play a vital role in the development of nuclear power and the defense industry. However, with the continuous development of emerging economies, global energy demand has further expanded, and the demand for natural uranium resources has also surged. Therefore, the search for sustainable uranium resources is of great significance. It is reported that the uranium reserves in seawater are approximately 4.5 billion tons, which is 1,000 times that of terrestrial uranium resources. Therefore, research on uranium extraction from seawater is an important way to achieve an adequate supply of uranium resources. Common methods for extracting uranium from seawater include membrane separation, photocatalysis, bioconcentration, and adsorption separation. Among them, adsorption separation is widely used in the field of uranium extraction from seawater due to its environmental friendliness, ease of operation, wide adaptability, and low cost.

[0003] Given the complex and diverse water environments in which uranyl ions exist, it is of great significance to develop high-performance adsorbents to improve the adsorption efficiency of the target. The amidoximated hollow mesoporous material prepared based on silica research has good biocompatibility and a stable three-dimensional structure. It is a material with a hollow structure and a mesoporous structure, with the advantages of high specific surface area, good pore size distribution and high pore capacity. Compared with traditional adsorbents, hollow mesoporous materials can provide more adsorption sites and a larger adsorption capacity; at the same time, their mesoporous structure is also conducive to the transport and diffusion of substances, thereby improving the adsorption efficiency. These characteristics give this material a wide range of application prospects in the adsorption and separation of uranyl ions. In addition, the hollow structure gives it a lower mass transfer resistance and higher stability, which is beneficial to the transport and mass transfer of fluids, and also provides favorable conditions for the material to achieve multifunctionality.

[0004] Micro- and nanomotor actuation methods generally fall into two categories: physical actuation and chemical actuation. While a considerable number of studies have examined the application of chemically driven motor adsorbents in adsorption and separation, relatively few studies have explored physical actuation methods. Compared to chemical actuation, physical actuation frees itself from the constraints of chemical fuels, enabling the regulation of motor motion and is more environmentally friendly and safer. Physical actuation typically involves magnetic fields, ultrasound, electric fields, and light. Among these, light actuation is more environmentally friendly, efficient, and readily available compared to other methods. Near-infrared (NIR)-driven photothermal motors are a current research hotspot and have been extensively studied in biomedicine, sensing, and environmental remediation. Au nanoparticles, as the core material for NIR-driven actuation, exhibit surface energy and optical properties that make them an ideal energy conversion material. Under illumination, localized hotspots form on the gold particle surface, generating nonequilibrium temperatures around the material, driving the motor's motion. Therefore, developing and preparing photothermally driven hollow mesoporous motor adsorbents to achieve multifunctionality and enhance uranyl ion adsorption efficiency is a promising research direction. Summary of the Invention

[0005] The present invention combines a photothermal driven motor with an AO functionalized mesoporous silicon layer to prepare a photothermal driven hollow mesoporous adsorbent for selective adsorption of uranyl ions. First, the properties of PDA on the PS@PDA surface are used to in situ reduce Au nanoparticles; then, the The method is to coat the material with a layer of silicon, and then use high-temperature calcination to remove the organic polymer template PS@PDA in the silicon shell to obtain the photothermal drive material SiO2∩Au; then the mesoporous silicon layer with C≡N is coated in one step through the co-condensation method, and it is reduced to AO functional groups by NH2OH·HCl to obtain the nanomotor adsorbent MSSA-AO. The present invention uses PS@PDA as a template to avoid the overlap of motor drive sites and adsorption sites, and constructs a hollow mesoporous adsorbent with both efficient and selective adsorption of uranyl ions and photothermal drive. In addition, the photothermally responsive hollow mesoporous adsorbent improves the mass transfer rate and solution mixing efficiency under the irradiation of near-infrared light, increases the contact opportunities between the target and the binding site, and further improves the adsorption efficiency. The present invention provides a new method for achieving efficient separation of uranyl ions in complex water bodies, and also further enriches the functional adsorbent material system.

[0006] The technical solution adopted in the present invention is:

[0007] A method for preparing a photothermal-driven amidoximated hollow mesoporous motor adsorbent comprises the following steps:

[0008] (1) Preparation of polystyrene particles PS:

[0009] First, PS was prepared using existing techniques. Specifically, a certain amount of styrene, deionized water, and polystyrene pyrrolidone were added to a round-bottom flask and ultrasonically dissolved. Stirring and heating to a certain temperature were performed under nitrogen flow for 15 minutes. Potassium persulfate was then added and allowed to react for a period of time. The product was collected by centrifugation, washed three times with deionized water and three times with ethanol, and dried in a vacuum oven. The resulting PS particles were then collected.

[0010] (2) Preparation of polydopamine-coated polystyrene particles PS@PDA

[0011] An appropriate amount of PS prepared in step (1) was ultrasonically dispersed in a certain amount of Tris-HCl solution, and a certain amount of dopamine (DA) was added. The reaction was allowed to proceed at room temperature for 24 hours. The product was collected by centrifugation and washed with deionized water and ethanol until the solution was clear. Finally, the product PS@PDA was collected in a vacuum oven.

[0012] (3) Preparation of PS@PDA@Au:

[0013] The PS@PDA prepared in step (2) was dispersed in a certain amount of deionized water, and then added to a certain amount of tetrachloroauric acid trihydrate aqueous solution, and stirred at room temperature for 24 hours; after the reaction was completed, the product was collected by centrifugation, and washed several times with deionized water and ethanol; finally, the product PS@PDA@Au was collected after vacuum drying;

[0014] (4) Preparation of hollow mesoporous motor adsorbent MSSA-AO:

[0015] S1: Weigh a certain amount of PS@PDA@Au obtained in step (3) and disperse it in a mixed solvent of ethanol and deionized water, and add an appropriate amount of ammonia NH3·H2O; magnetically stir for 1.0 h, then add a certain amount of tetraethyl silicate TEOS, and stir the reaction at room temperature for a certain time; after the reaction, centrifuge and collect the product, wash it with deionized water and ethanol several times, and vacuum dry it to collect the product SiO2-PS@PDA@Au;

[0016] S2: calcining SiO2-PS@PDA@Au in a tube furnace under certain conditions to remove PS@PDA; collecting the product SiO2∩Au after a period of time;

[0017] S3: A certain amount of SiO2∩AU was dispersed in a mixed solvent of deionized water and ethanol, and an appropriate amount of NH3·H2O and hexadecyltrimethylammonium bromide (CTAB) was added, and the mixture was stirred continuously for 0.5 h. Then, a mixture of tetraethyl silicate (TEOS) and 2-cyanoethyltriethoxysilane (CTES) was added and the mixture was reacted at room temperature for a certain time. After the reaction, the product was collected by centrifugation, washed several times with deionized water and ethanol, and vacuum dried to collect the product MSSA. Finally, the MSSA was dispersed in 50 ml of ethanol solution and refluxed at 100°C for 24 h to remove the CTAB.

[0018] S4: Weigh a certain amount of hydroxylamine hydrochloride NH2OH·HCl and dissolve it in a mixed solvent of deionized water and ethanol, and add an appropriate amount of sodium hydroxide NaOH; then disperse a certain amount of MSSA in the above solution and react at a certain temperature for a period of time; after the reaction, centrifuge and collect the product, wash it with deionized water and ethanol several times, and vacuum dry it to collect the product MSSA-AO

[0019] Preferably, in step (1), the ratio of styrene, deionized water, polyvinyl pyrrolidone and potassium persulfate is 40 ml: 250 mL: 1.346 g: 0.54 g, the reaction temperature is heated to 75-80° C., and the rotation speed is 500-600 rpm.

[0020] Preferably, in step (1), the reaction time is 24 hours.

[0021] Preferably, in step (2), the amount ratio of PS, dopamine (DA) and Tris-HCl buffer solution (10 mM pH = 8.5) is 0.2 g:0.2 g:100 ml.

[0022] Preferably, in step (3), the dosage ratio of the PS@PDA, deionized water, and tetrachloroauric acid trihydrate aqueous solution is 0.09 g:100 mL:3 mL, wherein the mass percentage concentration of the tetrachloroauric acid trihydrate aqueous solution is 0.75%-1.5%.

[0023] Preferably, in S1 of step (4), the amount ratio of PS@PDA@Au, deionized water, ethanol, NH3·H2O and TEOS is 90 mg:6 mL:105 mL:1.5 mL:1.5 mL, and the mass percentage concentration of NH3·H2O is 25%; at room temperature, the stirring speed is 250-300 rpm, and the reaction time is 8.0-10 h.

[0024] Preferably, in step (4) S2, PS@PDA is removed by calcination in a tube furnace at a temperature of 5°C·min -1 Heat to 500℃, maintain for 6 hours and then cool naturally.

[0025] Preferably, in S3 of step (4), the amount ratio of SiO2∩AU, deionized water, ethanol, NH3·H2O, CTAB, TEOS and CTES is 50 mg:80 mL:60 mL:1 mL:300 mg:0.15-0.3 mL:0.05-0.15 mL, and the mass percentage concentration of NH3·H2O is 25%; at room temperature, the stirring speed is 250-300 rpm, and the reaction time is 6.0 h.

[0026] Preferably, in S4 of step (4), the volume ratio of deionized water and ethanol is 1:9; the amount ratio of MSSA, deionized water, ethanol, NH2OH·HCl and NaOH is 50 mg:5 mL:45 mL:2 g:1.152 g, the reaction temperature is 75-80°C, and the reaction time is 10.0-12 h.

[0027] The hollow mesoporous motor adsorbent MSSA-AO prepared by the present invention is used for extracting uranium.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The present invention uses PS@PDA modified with Au nanoparticles as a template to coat a silicon layer, and completely calcines and removes the template PS@PDA at 500°C to obtain a hollow material containing Au particles (SiO2∩Au). Then, the mesoporous silicon layer containing C≡N is modified in one step by a co-condensation method and the cyanide is reduced to an amidoxime functional group to obtain an amidoxime-modified hollow mesoporous material (MSSA-AO). The adsorption efficiency of the adsorbent for uranyl ions is improved, and the motor is freed from the constraints of chemical fuels. A hollow mesoporous material with a photothermal drive effect is prepared to study uranium extraction from seawater. Adsorption experiments have shown that MSSA-AO has an excellent adsorption capacity for uranyl ions at pH = 8.0, and can enter the adsorption equilibrium stage in about 30 minutes; in addition, at 1.0 W / cm 2 and 1.2W / cm 2 Under near-infrared light irradiation, MSSA-AO reacts with UO2 2+ Compared with the case without light, the adsorption capacity and adsorption rate have been significantly improved. At the same time, the adsorbent has ideal selectivity and regeneration ability. In summary, this work successfully prepared a photothermal-driven hollow mesoporous adsorbent, which improved the adsorption of UO2 2+ The adsorption efficiency is improved, which enriches the driving mode of the motor and further expands the research on motor adsorbents with different driving modes in the direction of uranium extraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 are SEM images of PS (a, c) and PS@PDA (b, d) in Example 1;

[0031] Figure 2 TEM images of SiO2-PS@PDA@Au (a, d), SiO2∩Au (b, e) and MSSA (c, f) in Example 1, respectively.

[0032] Figure 3 IR spectra of PS, PS@PDA, MSSA and MSSA-AO in Example 1.

[0033] Figure 4 (a) pH-adsorption capacity diagram and (b) Zeta potential diagram of MSSA-AO.

[0034] Figure 5 This is the time-adsorption capacity graph of MSSA-AO.

[0035] Figure 6 This is the time-adsorption capacity diagram of MSSA-AO under near-infrared light irradiation.

[0036] Figure 7 These are the equilibrium concentration-adsorption capacity diagrams of MSSA-AO at 298K and 308K respectively.

[0037] Figure 8 This is a test of the selectivity of MSSA-AO for the target substance U(VI) in simulated seawater.

[0038] Figure 9 It is the regeneration performance test of MSSA-AO. DETAILED DESCRIPTION

[0039] Example 1:

[0040] (1) Preparation of polystyrene particles PS:

[0041] First, 40 mL of styrene (ST) and 1.346 g of polystyrene pyrrolidone (PVP) were added to 250 mL of deionized water for sonication and slowly heated to 75°C at 500 rpm under nitrogen for 15 minutes. Subsequently, 0.54 g of potassium persulfate (KPS) was added and allowed to react for 24 hours. The product was collected by centrifugation, washed three times with deionized water and ethanol, and dried in a vacuum oven at 45°C for 24 hours to obtain PS nanoparticles.

[0042] (2) Preparation of polystyrene particles PS@PDA coated with polydopamine:

[0043] 0.2 g of the PS nanoparticles prepared in step (1) were ultrasonically dispersed in 100 mL of Tris-HCl (10 mM pH = 8.5) solution, and 0.2 g of dopamine (DA) was added. The mixture was reacted at 25°C for 24 h. The product was collected by centrifugation, washed with deionized water and ethanol until the solution was clear, and finally dried in a vacuum oven at 45°C for 24 h to obtain the product PS@PDA.

[0044] (3) Preparation of PS@PDA@Au:

[0045] Weigh 0.09 g of the PS@PDA prepared in step (2) and 3 ml of a 0.75% aqueous solution of HAuCl4 in 100 mL of deionized water. React at room temperature for 24 h, and collect the product by centrifugation. Wash the product three times with deionized water and three times with ethanol, then dry it in a vacuum oven at 45°C for 24 h to obtain PS@PDA@Au.

[0046] (4) Preparation of hollow mesoporous motor adsorbent MSSA-AO:

[0047] First, 0.09 g of PS@PDA@Au was weighed and added to a 250 mL round-bottom flask. 6 mL of deionized water and 105 mL of ethanol were added. After ultrasonic dispersion, 1.5 mL of NH₃·H₂O was added. The reaction was stirred magnetically for 1 hour, followed by 1.5 mL of TEOS. The reaction continued at room temperature for 8 hours, and the product was collected by centrifugation. The product was washed several times with deionized water and ethanol and dried in a vacuum oven at 45°C for 24 hours to obtain SiO₂-PS@PDA@Au.

[0048] SiO2-PS@PDA@Au was calcined in a tube furnace to remove PS@PDA at a temperature of 5℃min -1 After the temperature was raised to 500°C and maintained for 6 hours, it was naturally cooled to obtain the photothermal driving material SiO2∩Au.

[0049] Next, 50 mg of the SiO∩AU hollow material was weighed and dispersed in 0.3 g of hexadecyltrimethylammonium bromide (CTAB), 80 mL of deionized water, 1 mL of 25% NH₃·H₂O, and 60 mL of ethanol. The mixture was allowed to react for half an hour. A mixture containing 0.15 mL of TEOS and 0.05 mL of 2-cyanoethyltriethoxysilane (CTES) was then added with continuous stirring. The mixture was allowed to react at room temperature for 6 hours. The cyanide-containing hollow mesoporous material (MSSA) was collected by centrifugation and washed. The collected material was then dispersed in 50 mL of ethanol and refluxed at 100°C for 24 hours to remove the CTAB.

[0050] Finally, 2.0 g of NH₂OH·HCl was dissolved in 50 mL of H₂O / ethanol solution (V / V = 5:45), and 1.152 g of NaOH was added. The cyanide-containing hollow mesoporous material was then dispersed in the solution and reacted at 80°C for 10 h. The final amidoximated hollow mesoporous material, MSSA-AO, was collected by centrifugation, washed several times with ethanol until the supernatant became clear, and dried in a vacuum oven at 45°C for 24 h to obtain the adsorbent MSSA-AO.

[0051] Figure 1 These are SEM images of PS (a, c) prepared in Example 1 (1) and PS@PDA (b, d) prepared in Example 1 (2). It can be seen from the figures that PS has uniform size and smooth surface. The size of PS@PDA is not much different from that of PS, but the surface is slightly rough, indicating that the modification is successful.

[0052] Figure 2 TEM images of SiO2-PS@PDA@Au (a, d), SiO2∩Au (b, e) and MSSA (c, f) prepared in Example 1 (4) show the similarities and differences between the three materials, indicating the successful preparation of hollow mesoporous materials.

[0053] Figure 3 These are the infrared spectra of PS prepared in Example 1(1), PS@PDA prepared in Example 1(2), MSAA and MSSA-AO prepared in Example 1(4). The changes in the surface functional groups of the four materials indicate that the materials were successfully prepared.

[0054] Example 2:

[0055] (1) Preparation of polystyrene particles PS:

[0056] First, 40 mL of styrene (ST) and 1.346 g of polystyrene pyrrolidone (PVP) were added to 250 mL of deionized water for sonication and slowly heated to 75°C at 500 rpm under nitrogen for 15 minutes. Subsequently, 0.54 g of potassium persulfate (KPS) was added and allowed to react for 24 hours. The product was collected by centrifugation, washed three times with deionized water and ethanol, and dried in a vacuum oven at 45°C for 24 hours to obtain PS nanoparticles.

[0057] (2) Preparation of polystyrene particles PS@PDA coated with polydopamine:

[0058] 0.2 g of the PS nanoparticles prepared in step (1) were ultrasonically dispersed in 100 mL of Tris-HCl (10 mM pH = 8.5) solution, and 0.2 g of dopamine (DA) was added. The mixture was reacted at 25°C for 24 h. The product was collected by centrifugation, washed with deionized water and ethanol until the solution was clear, and finally dried in a vacuum oven at 45°C for 24 h to obtain the product PS@PDA.

[0059] (3) Preparation of PS@PDA@Au:

[0060] 0.09 g of PS@PDA prepared in step (2) and 3 ml of 1% aqueous HAuCl4 solution were weighed and added to 100 mL of deionized water. The mixture was reacted at room temperature for 24 h, and the product was collected by centrifugation. The product was washed three times with deionized water and ethanol, and dried in a vacuum oven at 45°C for 24 h to obtain the product PS@PDA@Au. (4) Preparation of hollow mesoporous motor adsorbent MSSA-AO:

[0061] First, weigh 0.09g PS@PDA@Au and add it to a 250mL round-bottom flask, and add 6mL deionized water and 105mL ethanol. After ultrasonic dispersion, add 1.5mL NH3.H2O, stir magnetically and react for 1h, then add 1.5mL TEOS, and continue to react for 8h at room temperature. Collect the product by centrifugation. Wash the product with deionized water and ethanol several times, put it in a vacuum oven at 45℃ and dry it for 24h to obtain the product SiO2-PS@PDA@Au. SiO2-PS@PDA@Au was placed in a tube furnace and calcined to remove PS@PDA at 5℃min -1 After the temperature was raised to 500°C and maintained for 6 hours, it was naturally cooled to obtain the photothermal driving material SiO2∩Au.

[0062] Next, 50 mg of the SiO∩AU hollow material was weighed and dispersed in 0.3 g of hexadecyltrimethylammonium bromide (CTAB), 80 mL of deionized water, 1 mL of 25% NH₃·H₂O, and 60 mL of ethanol. The mixture was allowed to react for half an hour. A mixture containing 0.2 mL of TEOS and 0.1 mL of 2-cyanoethyltriethoxysilane (CTES) was then added with continuous stirring. The mixture was allowed to react at room temperature for 6 hours. The cyanide-containing hollow mesoporous material (MSSA) was collected by centrifugation and washed. The collected material was then dispersed in 50 mL of ethanol and refluxed at 100°C for 24 hours to remove the CTAB.

[0063] Finally, 2.0 g of NH₂OH·HCl was dissolved in 50 mL of H₂O / ethanol solution (V / V = 5:45), and 1.152 g of NaOH was added. The cyanide-containing hollow mesoporous material was then dispersed in the solution and reacted at 75°C for 10 h. The final amidoximated hollow mesoporous material (MSSA-AO) was collected by centrifugation, washed several times with ethanol until the supernatant became clear, and dried in a vacuum oven at 45°C for 24 h to obtain the adsorbent MSSA-AO.

[0064] Example 3:

[0065] (1) Preparation of polystyrene particles PS:

[0066] First, 40 mL of styrene (ST) and 1.346 g of polystyrene pyrrolidone (PVP) were added to 250 mL of deionized water for sonication and slowly heated to 75°C at 500 rpm under nitrogen for 15 minutes. Subsequently, 0.54 g of potassium persulfate (KPS) was added and allowed to react for 24 hours. The product was collected by centrifugation, washed three times with deionized water and ethanol, and dried in a vacuum oven at 45°C for 24 hours to obtain PS nanoparticles.

[0067] (2) Preparation of polystyrene particles PS@PDA coated with polydopamine:

[0068] 0.2 g of the PS nanoparticles prepared in step (1) were ultrasonically dispersed in 100 mL of Tris-HCl (10 mM pH = 8.5) solution, and 0.2 g of dopamine (DA) was added. The mixture was reacted at 25°C for 24 h. The product was collected by centrifugation, washed with deionized water and ethanol until the solution was clear, and finally dried in a vacuum oven at 45°C for 24 h to obtain the product PS@PDA.

[0069] (3) Preparation of PS@PDA@Au:

[0070] Weigh 0.09 g of the PS@PDA prepared in step (2) and 3 ml of a 1.5% aqueous solution of HAuCl4 tetrachloroaurate to 100 mL of deionized water. React at room temperature for 24 h, and collect the product by centrifugation. Wash the product three times with deionized water and three times with ethanol, then dry it in a vacuum oven at 45°C for 24 h to obtain PS@PDA@Au.

[0071] (4) Preparation of hollow mesoporous motor adsorbent MSSA-AO:

[0072] First, weigh 0.09g PS@PDA@Au and add it to a 250mL round-bottom flask, and add 6mL deionized water and 105mL ethanol. After ultrasonic dispersion, add 1.5mL NH3.H2O, stir magnetically and react for 1h, then add 1.5mL TEOS, and continue to react for 8h at room temperature. Collect the product by centrifugation. Wash the product with deionized water and ethanol several times, put it in a vacuum oven at 45℃ and dry it for 24h to obtain the product SiO2-PS@PDA@Au. SiO2-PS@PDA@Au was placed in a tube furnace and calcined to remove PS@PDA at 5℃min -1 After the temperature was raised to 500°C and maintained for 6 hours, it was naturally cooled to obtain the photothermal driving material SiO2∩Au.

[0073] Next, 50 mg of the SiO∩AU hollow material was weighed and dispersed in 0.3 g of hexadecyltrimethylammonium bromide (CTAB), 80 mL of deionized water, 1 mL of 25% NH₃·H₂O, and 60 mL of ethanol. The mixture was allowed to react for half an hour. A mixture containing 0.3 mL of TEOS and 0.15 mL of 2-cyanoethyltriethoxysilane (CTES) was then added with continuous stirring. The mixture was allowed to react at room temperature for 6 hours, and the cyanide-containing hollow mesoporous material (MSSA) was collected by centrifugation and washing. The collected material was then dispersed in 50 mL of ethanol and refluxed at 100°C for 24 hours to remove the CTAB.

[0074] Finally, 2.0 g of NH₂OH·HCl was dissolved in 50 mL of H₂O / ethanol solution (V / V = 5:45), and 1.152 g of NaOH was added. The cyanide-containing hollow mesoporous material was then dispersed in the solution and reacted at 75°C for 12 h. The final amidoximated hollow mesoporous material (MSSA-AO) was collected by centrifugation, washed several times with ethanol until the supernatant became clear, and dried in a vacuum oven at 45°C for 24 h to obtain the adsorbent MSSA-AO.

[0075] Test Example 1:

[0076] 2.0 mg of MSSA-AO prepared in Example 1 (4) was weighed and 10 mL of 10 ppm U(VI) solution was added. Static adsorption was carried out at 25°C for 1.0 h at pH 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, and 9.0, respectively. Three parallel experiments were performed for each condition.

[0077] Figure 4 Figure 2 is the pH-adsorption capacity diagram (a) and Zeta potential diagram (b) of MSSA-AO. It can be seen from the figure that the optimal adsorption pH value of MSSA-AO is 8.0.

[0078] Test Example 2:

[0079] Weigh 2.0 mg of the MSSA-AO prepared in Example 1 (4) and, under the optimal pH conditions for MSSA-AO adsorption in Test Example 1, perform static adsorption at 25°C in 10 mL of 10 ppm U(VI) solution for 5.0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 90 min, and 120 min, and collect the adsorbed liquid. Perform three parallel experiments for each case.

[0080] Figure 5 This is the time-adsorption capacity diagram of MSSA-AO. It can be seen from the figure that MSSA-AO reaches adsorption equilibrium for the target substance U(VI) in about 30 minutes.

[0081] Test Example 3:

[0082] Weigh 2.0 mg of the MSSA-AO prepared in Example 1 (4) and, under the optimal pH conditions for MSSA-AO adsorption in Test Example 1, add 10 mL of a 10 ppm U(VI) solution at 25°C and 0 W / cm 2 , 1.0W / cm 2 and 1.2W / cm 2 The adsorption liquid was irradiated with near-infrared light of different output powers for 5.0 min, 10 min, 20 min and 30 min, and the adsorption liquid was collected.

[0083] Figure 6 This is the time-adsorption capacity diagram of MSSA-AO under near-infrared light irradiation. It can be seen from the figure that after 1.0W / cm 2 and 1.2W / cm 2 Adsorption capacity of the test liquid at each time period after near-infrared light irradiation t The results were both higher than those without near-infrared light irradiation. This is attributed to the fact that near-infrared light irradiation increases the temperature of the test solution, which is conducive to adsorption. At the same time, the movement of the nanomotor increases the probability of contact between the target and the binding site. This proves that near-infrared light irradiation accelerates the adsorption process and improves adsorption efficiency.

[0084] Test Example 4:

[0085] Weigh 2.0 mg of the MSSA-AO prepared in Example 1 (4), select the optimal pH value for the adsorption of MSSA-AO in Test Example 1, and statically adsorb for 1.0 h in 10 mL of U(VI) solutions with concentrations of 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, and 70 ppm at temperatures of 298 K and 308 K, respectively. Three parallel experiments were performed for each case.

[0086] Figure 7This is the equilibrium concentration-adsorption capacity diagram of MSSA-AO at 298K and 308K. It can be seen from the figure that as the temperature increases, the adsorption capacity of MSSA-AO also increases.

[0087] Test Example 5:

[0088] Weigh 2.0 mg of MSSA-AO prepared in Example 1 (4) and add it to the mixture containing UO2 2+ (330ppb), VO 3- (260ppb), Fe 3+ (1.7ppb), Co 2+ (5.0ppb), Ni + (90ppb), Zn 2+ (1.05ppb), Pb 2+ (3.0ppb), K + (0.65*10 6 ppb), Na + (10.26*10 6 ppb), Ca 2+ (0.92*10 6 ppb), Mg 2+ (1.22*10 6 The static adsorption was carried out in a simulated seawater solution with a concentration of 1 ppb at room temperature (25°C) for 1 h. Three parallel experiments were conducted. The supernatant was collected by centrifugation and the ion concentration was detected by inductively coupled plasma emission spectrometry (ICP).

[0089] Figure 8 This is the selectivity test of MSSA-AO for the target substance U(VI) in simulated seawater. The figure shows that MSSA-AO has good selectivity for U(VI).

[0090] Test Example 6:

[0091] Weigh 20ml of MSSA-AO prepared in Example 1 (4) and place it in UO2 2+ After adsorption in the solution for a period of time, the solution was collected by centrifugation and dried under vacuum. Weigh multiple 2 mg portions of MSSA-AO into separate 10 mL centrifuge tubes, add 5 mL of 0.1 M HNO3 as the eluent, allow to stand for 4.0 h, collect by centrifugation, and dry for the next adsorption cycle.

[0092] Figure 9 This is the regeneration performance test of MSSA-AO. It can be seen from the figure that after five cycles, MSSA-AO still maintains 80% of its initial adsorption capacity for U(VI), indicating that MSSA-AO has good regeneration performance.

Claims

1. A method for preparing amidoximated hollow mesoporous motor adsorbent based on a hard template method, characterized in that: The following steps are involved: (1) Preparation of polystyrene particles PS; (2) Preparation of polystyrene particles PS@PDA coated with polydopamine; (3) Preparation of PS@PDA@Au: The PS@PDA prepared in step (2) is dispersed in a certain amount of deionized water, and then added to a certain amount of tetrachloroauric acid trihydrate aqueous solution, and stirred for a period of time at room temperature; after the reaction is completed, the product is collected by centrifugation, and washed several times with deionized water and ethanol; finally, the product PS@PDA@Au is collected after vacuum drying; (4) Preparation of hollow mesoporous motor adsorbent MSSA-AO: S1: Weigh a certain amount of PS@PDA@Au obtained in step (3) and disperse it in a mixed solvent of ethanol and deionized water, and add an appropriate amount of ammonia NH3·H2O; magnetically stir for a period of time, then add a certain amount of tetraethyl silicate TEOS, and stir and react at room temperature for a certain period of time; after the reaction, centrifuge and collect the product, wash it with deionized water and ethanol several times, and vacuum dry it to collect the product SiO2-PS@PDA@Au; S2: calcining SiO2-PS@PDA@Au in a tube furnace under certain conditions to remove PS@PDA; collecting the product SiO2∩Au after a period of time; S3: A certain amount of SiO2∩Au is dispersed in a mixed solvent of deionized water and ethanol, and an appropriate amount of NH3·H2O and hexadecyltrimethylammonium bromide (CTAB) is added, and the mixture is stirred and reacted for a period of time; then a mixture of tetraethyl silicate (TEOS) and 2-cyanoethyltriethoxysilane (CTES) is added, and the mixture is reacted at room temperature for a certain period of time; after the reaction, the product is collected by centrifugation, washed several times with deionized water and ethanol, and vacuum dried to collect the product MSSA; finally, the MSSA is dispersed in an appropriate amount of ethanol solution and refluxed at a certain temperature for a period of time to remove the CTAB; S4: Weigh a certain amount of hydroxylamine hydrochloride (NH2OH·HCl) and dissolve it in a mixed solvent of deionized water and ethanol, and add an appropriate amount of sodium hydroxide (NaOH). Then, disperse a certain amount of MSSA in the above solution and react at a certain temperature for a period of time. After the reaction is completed, the product is collected by centrifugation, washed several times with deionized water and ethanol, and vacuum dried to collect the product MSSA-AO.

2. The method according to claim 1, wherein In step (2), the preparation steps of polydopamine-coated polystyrene particles PS@PDA are as follows: taking an appropriate amount of PS in step (1) and ultrasonically dispersing it in a certain amount of Tris-HCl solution, then adding a certain amount of dopamine DA, reacting at room temperature for 24 hours, collecting the product by centrifugation, and washing with deionized water and ethanol until the solution is clear, and finally placing it in a vacuum oven to collect the product PS@PDA; The dosage ratio of PS, dopamine DA and Tris-HCl buffer solution is 0.2 g:0.2 g:100 mL; the concentration of Tris-HCl buffer solution is 10 mM, and the pH is 8.

5.

3. The method according to claim 1, wherein In step (3), the amount ratio of PS@PDA, deionized water, and tetrachloroauric acid trihydrate aqueous solution is 0.09 g: 100 mL: 3 mL. Wherein, the mass percentage concentration of tetrachloroauric acid trihydrate aqueous solution is 0.75%-1.5%, The reaction time is 24h.

4. The method according to claim 1, wherein In step (4) S1, the amount ratio of PS@PDA@Au, deionized water, ethanol, NH3·H2O and TEOS is 90 mg:6 mL:105 mL:1.5 mL:1.5 mL, and the mass percentage concentration of NH3·H2O is 25%; The magnetic stirring time was 1.0 h; When the reaction is stirred at room temperature, the stirring speed is 250-300 rpm and the reaction time is 8.0-10 h.

5. The method according to claim 1, wherein In step (4) S2, PS@PDA is removed by calcination in a tube furnace at a temperature of 5°C·min -1 Heat to 500℃, maintain for 6 hours and then cool naturally.

6. The method according to claim 1, wherein In S3 of step (4), the usage ratio of SiO2∩Au, deionized water, ethanol, NH3·H2O, CTAB, TEOS and CTES is 50 mg:80 mL:60 mL:1 mL:300 mg:0.15-0.3 mL:0.05-0.15 mL, and the mass percentage concentration of NH3·H2O is 25%.

7. The method according to claim 1, wherein In step (4) S3, The continuous stirring reaction time was 0.5 h; When the reaction is carried out at room temperature, the stirring speed is 250-300 rpm and the reaction time is 6.0 h.

8. The method according to claim 1, wherein In S4 of step (4), the volume ratio of deionized water and ethanol is 1:9; wherein the amount ratio of MSSA, deionized water, ethanol, NH2OH·HCl and NaOH is 50 mg:5 mL:45 mL:2 g:1.152 g.

9. The method according to claim 1, wherein In step (4) S4, The reaction temperature is 75-80°C, and the reaction time is 10.0-12h.

10. Use of the hollow mesoporous motor adsorbent MSSA-AO prepared by the method according to any one of claims 1 to 9 for extracting uranium.

Images