A method for preparing aerogel for selecting and separating radionuclide cesium in water and application thereof

Abstract

The present application belongs to the field of wastewater treatment technology and energy saving and environmental protection, and particularly relates to a method for preparing aerogel for selectively separating radionuclide cesium in water and application thereof. Graphene oxide is prepared by using hydrothermal technology, and then molybdenum disulfide / GO aerogel is prepared by using hydrothermal synthesis and ultrasonic technology, and then prussian blue (PB) is inlaid and grown on the surface of the aerogel, so as to solve the problems of easy agglomeration and difficult recovery of PB and MoS2, endow the GO aerogel with multifunction, and construct PB / MoS2 / GO aerogel for selectively separating radionuclide cesium in water. The selective separation performance of the aerogel for radionuclide cesium in water under different conditions is investigated, the highly efficient enrichment and recovery of radionuclide cesium are effectively realized by using the super-light and highly porous characteristics of the aerogel, and the application potential of the aerogel in reducing secondary pollution and improving environmental governance effect is verified. The present application provides an efficient and environmentally friendly solution for radionuclide wastewater treatment, and has a wide market application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a preparation method of aerogel for selectively separating cesium from water and application thereof. BACKGROUND

[0002] Cesium isotope is the main component of radioactive wastewater, which is derived from uranium nuclear fission and is the main source of radiation. Cesium in wastewater mainly exists in the form of ions, which has high biological toxicity, strong migration ability, high radioactivity and long half-life. If it is directly released into the natural environment without safe treatment, it is easy to enter the human body through the food chain. Cesium mainly accumulates in muscles and bones, which can cause cancer, leukemia, genetic diseases and the like. At present, adsorption separation technology is concerned due to its high efficiency, simplicity and convenience. MoS2 is a two-dimensional transition metal sulfide similar to graphene, which has a unique sandwich structure of three stacked atomic layers (S-Mo-S). According to the Lewis acid-base principle, the rich sulfur groups on the surface and edges of MoS2 as Lewis bases can form coordination complexes with cesium ions, thereby enhancing the enrichment capacity of MoS2 for cesium. However, the powdery form of MoS2 makes it easy to agglomerate in water and poor in dispersibility, which affects the application effect. PB is a multifunctional adsorbent capable of selectively removing radioactive cesium. Due to the arrangement of iron atoms and ferrous ions in the cubic lattice structure, PB exhibits excellent cesium ion adsorption capacity. However, the agglomeration of PB and the separation after use become the bottleneck of application.

[0003] Aerogels can effectively capture and separate various target substances such as heavy metal ions, organic pollutants, etc. through specific surface modification and functionalization due to their high porosity, low density, and large specific surface area. In the patent CN202210453266.6 mentioned, the magnetic PB / Fe3O4 / MoS2 composite material is also related to the removal of heavy metal ions, but its focus is on the use of magnetic characteristics. This material may exhibit some convenience in the recycling process, but due to its lack of ultra-high specific surface area and porous structure, the adsorption performance is reduced, with the adsorption capacity of PB / MoS2 material being only about 10 mg / g, and the adsorption equilibrium time is long. And PB / Fe3O4 / MoS2 magnetic composite has some restrictive shortcomings in environmental remediation and water treatment applications, such as insufficient oxidation stability, which may lead to a decrease in magnetic performance; there is a risk of secondary pollution, and free iron ions may have a negative impact on the environment; sensitive to acid and alkaline environments, limiting its application range. GO is a carbon-based material with high specific surface area and rich oxygen-containing functional groups. These hydroxyl and carboxyl groups make it show strong hydrophilicity in water, and its layered structure enables it to effectively adsorb various pollutants when interacting with water molecules, achieving wastewater pollution purification. However, its selectivity for pollutants is poor, limiting its further application. It is worth noting that in patent CN202311242446.0, MoS2-PEI is combined with GO, and ZIF-8 is further grown by hydrothermal method. Although this method makes the aerogel obtain a higher specific surface area and porosity, it may be insufficient in functionalization, especially the selective binding performance with specific radionuclides (such as cesium) and greater adsorption capacity have not been fully utilized.

[0004] Therefore, considering the limitations of GO, MoS2, and PB and the urgency of removing the harmful radionuclide cesium, a PB / MoS2 / GO aerogel with ultra-high specific surface area, chemical stability, and excellent selective separation performance for cesium is proposed, aiming to play their respective advantages in wastewater treatment, especially in the removal of radionuclides. That is, GO is used as a carrier to enhance the dispersibility of MoS2, while also having a higher specific surface area of GO to further improve the overall adsorption performance. At the same time, according to the Lewis acid-base principle, the rich sulfur groups on the surface and edges of the aerogel can significantly improve its enrichment performance for the radionuclide cesium. In addition, PB is introduced into the composite aerogel, and the high specific surface area and porous structure of the aerogel can provide a large number of growth sites, which is beneficial to the enrichment and capture of radionuclides. Through the synergistic effect between the three materials, not only can the efficiency of wastewater treatment be improved, but also a new solution is provided for the separation and recovery of radionuclides. SUMMARY

[0005] The application aims to provide a method for preparing aerogel for selectively separating radionuclide cesium in water and application thereof, and construct PB / MoS2 / GO aerogel with super-high specific surface area, chemical stability and excellent selective separation performance as an adsorbent for treating wastewater containing cesium, so as to separate cesium ions through selective separation technology and solve the problem of radioactive wastewater treatment, which has good application prospect.

[0006] The application provides a method for preparing aerogel for selectively separating radionuclide cesium in water and application thereof, which comprises the following operation steps:

[0007] S1, MoS2 / GO aerogel is prepared by a hydrothermal method, GO dispersion liquid and MoS2 dispersion liquid are mixed and ultrasonically treated, then polyacrylic acid aqueous solution and H2O2 solution are added for high-temperature reaction, the MoS2 / GO hydrogel is obtained after being cooled to room temperature, and the MoS2 / GO aerogel is obtained after freeze-drying;

[0008] S2, the MoS2 / GO hydrogel is added into a mixed solution of ferric chloride and citric acid, and is taken out after a period of reaction; then a mixed solution of potassium ferrocyanide and citric acid is added, and is taken out after reaction and washing, the process is repeated for 1-3 times, and the PB / MoS2 / GO aerogel is obtained after freeze-drying.

[0009] Preferably, the concentration of the GO dispersion liquid is 5 mg / mL, the concentration of the MoS2 solution is 2 mg / mL, the concentration of the polyacrylic acid aqueous solution is 1 mg / mL, and the mass fraction of the H2O2 solution is 30%; the volume ratio of the GO dispersion liquid to the MoS2 solution to the polyacrylic acid aqueous solution to the H2O2 solution is 5-10:6-12:0.5-1:1.5-3.

[0010] Preferably, the GO dispersion liquid and the MoS2 dispersion liquid are mixed and ultrasonically treated for 1-1.5 h, then the H2O2 solution is added, and then the polyacrylic acid aqueous solution is added and transferred into a high-temperature hydrothermal kettle at 180 DEG C, and the reaction time is 7-9 h.

[0011] Preferably, in the mixed solution of potassium ferrocyanide (K4[Fe(CN)6]) and citric acid, the molar ratio of K4[Fe(CN)6] to citric acid is 1:0.05; and in the mixed solution of ferric chloride and citric acid, the molar ratio of FeCl3 to citric acid is 1:0.05.

[0012] Preferably, the mixed solution of ferric chloride and citric acid is prepared by mixing 1 mmol of FeCl3 and 0.05 mmol of citric acid in 20 mL of deionized water and magnetically stirring for 0.5 h; and the mixed solution of potassium ferrocyanide (K4[Fe(CN)6]) and citric acid is prepared by mixing 1 mmol of K4[Fe(CN)6] and 0.05 mmol of citric acid in 20 mL of deionized water and magnetically stirring for 0.5 h.

[0013] Furthermore, in step S2, the K4[Fe(CN)6] mixed solution is allowed to stand for 1 to 2 h for adsorption reaction.

[0014] Furthermore, in step S2, the FeCl3 mixed solution is allowed to stand for adsorption reaction for 1 to 1.5 h.

[0015] Preferably, the molar ratio of MoS2 to potassium ferrocyanide or ferric chloride is 0.1-0.2:1-3.

[0016] Preferably, the freeze-drying temperature is -50 to -60°C and the vacuum degree is 23 Pa.

[0017] The PB / MoS2 / GO aerogel is simple to prepare by sequentially adsorbing FeCl3 and K4[Fe(CN)6]. It exhibits excellent high-temperature resistance and adsorption capacity, making it a promising adsorbent. Furthermore, the aerogel exhibits an interconnected porous structure, ultralight weight, greatly improved water stability, and excellent cesium adsorption selectivity. Its high efficiency, rapidity, and selective adsorption of cesium in simulated wastewater and actual seawater demonstrate its potential for practical applications.

[0018] More importantly, in the present invention, PB nanoparticles are evenly embedded in the MoS2 / GO aerogel matrix and can come into contact with cesium ions in the wastewater, greatly improving the adsorption effect and further enhancing the aerogel's ability to treat cesium-containing wastewater.

[0019] In the present invention, PB / MoS2 / GO aerogel is used as an adsorbent to adsorb cesium-containing wastewater.

[0020] Furthermore, the PB / MoS2 / GO aerogel is highly stable in a wide pH range (2≤pH≤11), has a high cesium adsorption capacity (84.98 mg / g), and can reach adsorption equilibrium within 0.5 h.

[0021] The second object of the present invention is to provide an adsorbent that selectively adsorbs cesium ions and has the same adsorption effect.

[0022] The above technical objectives of the present invention are achieved by the following technical solutions:

[0023] This invention provides a method for selectively separating cesium from wastewater using a PB / MoS2 / GO aerogel. Specifically, the PB / MoS2 / GO aerogel is added to the cesium-containing wastewater to be treated, oscillated in a constant-temperature oscillator for 24-25 hours, and then removed from the screw-cap bottle. The supernatant is collected and filtered, and the cesium concentration in the filtrate is measured. The cesium adsorption efficiency of the PB / MoS2 / GO aerogel is calculated.

[0024] In summary, the present application has the following beneficial effects:

[0025] (1) The prepared PB / MoS2 / GO aerogel has large pores, light density, and the surface is successfully inlaid with PB nanoparticles, and has good cesium ion selective separation performance, the adsorption capacity is 84.98 mg / g, and the applicable pH range is wider.

[0026] (2) The synthesis technology of PB / MoS2 / GO aerogel is simple, the application method is easy, low consumption, energy saving, environmental protection, and can be recycled and reused, and has good purification effect on cesium-containing wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a physical photo of PB / MoS2 / GO aerogel;

[0028] Figure 2 It is a SEM diagram of PB / MoS2 / GO aerogel;

[0029] Figure 3 It is an XRD diagram of GO aerogel, MoS2 / GO aerogel and PB / MoS2 / GO aerogel;

[0030] Figure 4 It is the selective removal performance of GO aerogel, MoS2 / GO aerogel and PB / MoS2 / GO aerogel on cesium in different concentrations;

[0031] Figure 5 It is the selective removal performance of GO aerogel, MoS2 / GO aerogel and PB / MoS2 / GO aerogel on cesium in different times;

[0032] Figure 6 It is the selective removal performance of GO aerogel, MoS2 / GO aerogel and PB / MoS2 / GO aerogel on cesium in different pH;

[0033] Figure 7 It is the selective removal performance of PB / MoS2 / GO aerogel on cesium in different ions. DETAILED DESCRIPTION

[0034] The present application will be further described below in conjunction with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application. Example 1:

[0035] S1, GO was synthesized by Hummers oxidation method. First, 23 mL of concentrated sulfuric acid was added to a 250 mL beaker under ice bath, then 0.5 g of graphite powder and 0.5 g of NaNO3 were slowly added under mechanical stirring, followed by slowly adding 3.0 g of K2MnO4 and mechanical stirring for 1 h; the graphite powder, NaNO 3、 The mass ratio of K2MnO4 is 1:1:6. Then, the beaker was transferred to an oil bath pot with a temperature of 35°C, and after stirring for 2 h, 46 mL of deionized water was slowly added to the flask, then the oil bath temperature was quickly raised to 90°C, and after stirring for 30 min, 100 mL of deionized water and 3 mL of H2O2 (30 wt%) were added, and the reaction was terminated after stirring uniformly, and the reaction liquid was bright yellow; then, the residual metal ions were washed away with 5wt% dilute HCI solution, and then washed with deionized water until neutral; finally, the obtained product was dispersed in 50 mL of deionized water and ultrasonic for 2 h to obtain a GO dispersion liquid;

[0036] S2, 1.249 g of ammonium molybdate ((NH4)6Mo7O2·4H2O) and 2.303 g of thiourea (CH4N2S) were dissolved in 35 mL of deionized water, and stirred vigorously for 30-40 min. Then, the mixed solution was transferred to a 50 mL reaction kettle and heated to 200°C for 24 h. After natural cooling to room temperature, the black product was washed several times with deionized water and ethanol, and then freeze-dried (-55°C, 48 h) to obtain MoS2 nanosheets;

[0037] S3, the GO dispersion liquid (10 mL, 5 mg / mL), MoS2 (12 mL, 2 mg / mL) were mixed and ultrasonic for 1 h, then H2O2 solution (30wt%; 3 mL) was added, followed by adding polyacrylic acid aqueous solution (1 mL, 1 mg / mL) and transferring to a high-temperature hydrothermal kettle (180°C, 8 h). MoS2 / GO aerogel was prepared by hydrothermal method, and freeze-dried for 24 h to obtain MoS2 / GO aerogel;

[0038] S4, 1 mmol FeCl3and 0.05 mmol citric acid were mixed in 20 mL deionized water, and magnetically stirred for 0.5 h, 1 mmol K4[Fe(CN)6] and 0.05 mmol citric acid were mixed in 20 mL deionized water, and magnetically stirred for 0.5 h, wherein the mass of K4[Fe(CN)6] was 0.42239 g, the mass of FeCl3was 0.2703 g, and the mass of citric acid was 0.0105 g. The MoS2 / GO hydrogel in S3 was placed in the mixed solution of 1 mmol FeCl3and 0.05 mmol citric acid, and after 1 h of reaction, it was taken out and placed in the mixed solution of 1 mmol K4[Fe(CN)6] and 0.05 mmol citric acid, and the reaction was continued for 2 h, and the loading process was repeated three times. Then it was taken out and freeze-dried for 24 h to obtain the PB / MoS2 / GO aerogel.

[0039] The application method is as follows:

[0040] 10 mg of the PB / MoS2 / GO aerogel in Example 1 was added to a system of 20 mL of a cesium solution with a concentration of 50 mg / L, and was placed in a shaking bed (120 r / min, 25°C) for shock adsorption for 12 h. The cesium removal rate in the cesium-containing wastewater was detected to be 92.20%, and the PB / MoS2 / GO aerogel was separated by simple suspension after adsorption.

[0041] Figure 1 It is a photograph of the PB / MoS2 / GO aerogel. The appearance of the PB / MoS2 / GO aerogel is shown in Figure 1 It contains many pores and has a light texture, and can be easily placed on dandelion flowers. In addition, the density of the PB / MoS2 / GO aerogel was calculated by direct weighing method to be in the range of 14.16-16.66 mg·cm -3 The density of the aerogel is lower than that of water.

[0042] Figure 2 It is a SEM graph of the PB / MoS2 / GO aerogel. Figure 2 The morphology of the PB / MoS2 / GO aerogel was characterized by SEM. The results show that there are a large number of holes on the surface of the PB / MoS2 / GO aerogel, and the pore channels are obvious, and are irregularly arranged in a honeycomb shape, and the pore walls are intercrossed and staggered. And many cubic particles are inlaid on the pore wall, which is mainly due to the growth of Prussian blue on the surface of the aerogel, and the particle size of the Prussian blue is about 100 nm.

[0043] Figure 3 It is an XRD graph of the PB / MoS2 / GO aerogel. Figure 3The crystal structure and phase composition of GO, MoS2 / GO and PB / MoS2 / GO aerogels were analyzed by XRD. Figure 3 As shown in the figure, a clear diffraction peak corresponding to GO was observed at 2θ = 25.8°, indicating that GO retains the physical and chemical properties of natural graphite. Compared with GO aerogel, MoS2 / GO aerogel has new diffraction characteristic peaks at 9.1°, 32.1° and 57.2°, which correspond to the (002), (100) and (110) crystal planes of MoS2, respectively. These findings are consistent with the MoS2 standard card, confirming the successful synthesis of MoS2 in the aerogel. Moreover, PB / MoS2 / GO aerogel not only has the diffraction characteristic peaks of MoS2, but also has new additional peaks at 2θ = 17.64° (200), 24.98° (220), 35.58° (400), 39.94° (420) and 43.94° (422), which are mainly from PB with higher crystallinity, further confirming that PB is firmly fixed on MoS2 / GO aerogel. Overall, the XRD analysis provides comprehensive information on the crystalline phases present in the composites, confirming the successful preparation of PB / MoS2 / GO and the stable binding of PB on the MoS2 / GO framework. Example 2:

[0044] S1. Synthesis of GO by Hummers oxidation method: same as in Example 1.

[0045] Preparation of S2 and MoS2 nanosheets: same as Example 1.

[0046] Preparation of S3 and MoS2 / GO aerogels: same as in Example 1.

[0047] In step S4, 2 mmol FeCl₃ and 0.1 mmol citric acid were mixed in 20 mL deionized water and magnetically stirred for 0.5 h. Then, 2 mmol K₄[Fe(CN)₆] and 0.1 mmol citric acid were mixed in 20 mL deionized water and magnetically stirred for 0.5 h. The mass of K₄[Fe(CN)₆] was 0.84478 g, the mass of FeCl₃ was 0.5406 g, and the mass of citric acid was 0.021 g. The MoS₂ / GO hydrogel in step S3 was placed in the 2 mmol FeCl₃ and 0.1 mmol citric acid solution. After reacting for 1 h, the hydrogel was removed and placed in a 2 mmol K₄[Fe(CN)₆] and 0.1 mmol citric acid solution. The reaction continued for another 2 h. This loading process was repeated three times. The hydrogel was then freeze-dried for 24 h to obtain the PB / MoS₂ / GO aerogel.

[0048] The application method is as follows:

[0049] Take example 2 to take PB / MoS2 / GO aerogel 10 mg, add to the system is 20 mL, cesium concentration is 50 mg / L solution, place in the shaking bed (120 r / min, 25℃) and carry out shock adsorption 12 h, after detection, the cesium removal rate in the cesium-containing wastewater can reach 95.20%, and the PB / MoS2 / GO aerogel is separated by simple suspension after adsorption. Example 3:

[0050] S1, synthesis of GO by Hummers oxidation method: same as example 1.

[0051] S2, preparation of MoS2 nanosheet: same as example 1.

[0052] S3, preparation of MoS2 / GO aerogel: same as example 1.

[0053] S4, mix 3 mmol FeCl3 and 0.15 mmol citric acid in 20 mL deionized water, magnetic stirring for 0.5 h, mix 3 mmol K4[Fe(CN)6] and 0.15 mmol citric acid in 20 mL deionized water, magnetic stirring for 0.5 h, the mass of K4[Fe(CN)6] is 1.26717 g, the mass of FeCl3 is 0.8109 g, and the mass of citric acid is 0.0315 g. Put the MoS2 / GO hydrogel in S2 into the mixed solution of 3 mmol FeCl3 and 0.15 mmol citric acid, take out after standing for 1 h, put into the mixed solution of 3 mmol K4[Fe(CN)6] and 0.15 mmol citric acid, continue to stand for 2 h, and the loading process is repeated three times. Then take out and freeze-dry for 24 h to obtain PB / MoS2 / GO aerogel.

[0054] Its application method is as follows:

[0055] Take example 3 to take PB / MoS2 / GO aerogel 10 mg, add to the system is 20 mL, cesium concentration is 50 mg / L solution, place in the shaking bed (120 r / min, 25℃) and carry out shock adsorption 12 h, after detection, the cesium removal rate in the cesium-containing wastewater can reach 95.20%, and the PB / MoS2 / GO aerogel is separated by simple suspension after adsorption.

[0056] The conclusions obtained in Examples 1-3 are as follows: PB / MoS2 / GO aerogels exhibit excellent cesium removal performance and the effectiveness of the synthesis method. The preparation process of PB / MoS2 / GO aerogels is stable, and its porous structure characteristics are confirmed by SEM and XRD analysis, which is suitable for adsorption materials. The removal rate of cesium increases with the increase of the amount of FeCl3 and K4[Fe(CN)6], respectively, to 92.20%, 95.20% and 98.20%. The low density of this aerogel makes it easy to separate and suitable for various environmental governance applications, especially in the removal of heavy metals, which has broad prospects. Overall, this study provides theoretical and practical support for the development of new environmental remediation materials, and further exploration of its application in complex wastewater and economic evaluation can be carried out in the future.

[0057] Comparative Example 1:

[0058] Comparative Example 1 differs from Example 1 in that only MoS2 / GO aerogels are prepared, and the preparation method of MoS2 / GO aerogels is the same as S1-S3 of Example 1.

[0059] Comparative Example 2:

[0060] Comparative Example 2 differs from Example 1 in that GO aerogels are prepared, and the preparation method of GO aerogels is as follows: after ultrasonicating GO dispersion liquid (10 mL, 5 mg / mL) for 1 h, H2O2 solution (30 wt%; 3 mL) is added, then polyacrylic acid aqueous solution (1 mL, 1 mg / mL) is added and transferred to a high-temperature hydrothermal kettle (180 ℃, 8 h), and after natural cooling to room temperature, freeze-drying at -56 ℃ for 24 h to obtain GO aerogels.

[0061] Figure 4 The selective removal performance of PB / MoS2 / GO aerogels, MoS2 / GO aerogels and GO aerogels for cesium in different concentrations; Figure 4It is disclosed that PB / MoS2 / GO aerogel, MoS2 / GO aerogel and GO aerogel have significant adsorption capacity for removing cesium (Cs) in wastewater. The adsorption capacity of PB / MoS2 / GO aerogel increases with the increase of initial cesium concentration. When the concentration is low (10-40 mg / L), the surface active site is rich, and the adsorption effect is good. When the concentration reaches the saturation point (80 mg / L), the adsorption capacity increases slowly. For MoS2 / GO aerogel, the saturation point is reached when the concentration is about 40 mg / L. At this time, the adsorption capacity of PB / MoS2 / GO aerogel (86.51±1.75 mg / g) is significantly higher than that of MoS2 / GO (43.81±3.41 mg / g) and GO aerogel (18.66±0.55 mg / g). The above results show that ① the adsorption capacity of PB / MoS2 / GO aerogel (86.51±1.75 mg / g) is significantly higher than that of the other two materials (MoS2 / GO aerogel and GO aerogel), and the adsorption capacity of PB / MoS2 / GO aerogel is significantly increased compared with GO aerogel and PB / MoS2. The synergistic effect of PB, MoS2 and GO aerogel makes PB / MoS2 / GO aerogel have higher adsorption capacity and can more effectively selectively capture cesium ions, and the affinity for cesium is significantly improved compared with the other two materials.

[0062] Figure 5 The selective removal performance of PB / MoS2 / GO aerogel for cesium at different times Figure 5 It is shown that the adsorption performance of PB / MoS2 / GO aerogel for cesium (Cs) is better than that of GO aerogel and MoS2 / GO aerogel, and the incorporation of PB significantly improves the adsorption capacity of aerogel. The adsorption process of PB / MoS2 / GO aerogel can be divided into two stages: the initial stage (0-60 minutes) of rapid combination of Cs, and then the equilibrium stage of surface saturation by Cs. PB / MoS2 / GO aerogel can reach adsorption equilibrium within 1 hour, and the equilibrium adsorption capacity is 86.46±2.29 mg / g, which is much higher than that of MoS2 / GO aerogel (44.12±2.79 mg / g) and GO aerogel (15.21±3.12 mg / g). The growth of MoS2 and PB increases the available active sites and enhances the affinity for Cs, significantly improving the adsorption performance of GO aerogel for cesium.

[0063] Figure 6 The selective removal performance of PB / MoS2 / GO aerogel for cesium at different pH values Figure 6The selective adsorption performance of PB / MoS2 / GO aerogel for cesium (Cs) under different pH conditions is shown, and the results show that with the change of pH, the removal rate first increases and then decreases, and the best removal rate appears between pH 7 and 8, and the adsorption capacity reaches 117.22±3.52 mg / g at pH 8, indicating that the aerogel has excellent removal effect on Cs in wastewater. The control experiment shows that the equilibrium adsorption capacity of MoS2 / GO aerogel and GO aerogel is 43.81±2.86 mg / g and 18.28±3.07 mg / g, respectively, further confirming the key role of PB and MoS2. The adsorption capacity of PB / MoS2 / GO aerogel changes with pH and can be divided into three stages: at low pH, the adsorption is inhibited due to protonation, in the neutral to slightly alkaline pH range, the adsorption capacity is enhanced, and when the pH exceeds the optimum pH, the adsorption capacity decreases due to anion exclusion.

[0064] Figure 7 The selective removal performance of PB / MoS2 / GO aerogel for cesium in different ions; Figure 7 The selective research of PB / MoS2 / GO aerogel for cesium ions (Cs) is shown. In the experiment, K+, Ca 2+ , Na + and Mg 2+ and other coexisting metal ions form different ion mixtures with 50 mg / L Cs solution, and the concentration ratio of metal ions to Cs is maintained at 100:1. The results show that in the presence of potassium ions, the adsorption capacity of PB / MoS2 / GO aerogel for Cs is significantly lower than that for other metal ions, and the former is 22.36±0.61 mg / g, while the latter is more than 80 mg / g. Specifically, the adsorption capacity in the presence of Ca, Na and Mg ions is more than 80 mg / g. This is mainly because the ionic radius of potassium ion is similar to that of Cs ion, which leads to more effective competition with Cs. However, these results prove that PB / MoS2 / GO aerogel still shows good selectivity for Cs in the presence of multiple metal ions, indicating its potential application value in the removal of Cs in nuclear wastewater.

[0065] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been shown by the above preferred embodiment, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A method for the preparation of aerogels for the selective separation of the radionuclide cesium from water, characterized in that, The preparation method comprises the following steps: S1, preparing MoS2 / GO aerogel by a hydrothermal method: mixing GO dispersion liquid and MoS2 dispersion liquid under ultrasonic wave, then adding polyacrylic acid aqueous solution and H2O2 solution to react at high temperature, cooling to room temperature to obtain MoS2 / GO hydrogel, freeze-drying to obtain MoS2 / GO aerogel; the volume ratio of GO dispersion liquid, MoS2 dispersion liquid, polyacrylic acid aqueous solution and H2O2 solution in step S1 is 5-10:6-12:0.5-1:1.5-3; the concentration of GO dispersion liquid is 5 mg / mL; the concentration of MoS2 dispersion liquid is 2 mg / mL; S2, adding MoS2 / GO hydrogel into a mixed solution of ferric chloride and citric acid, taking out after a period of reaction, then adding a mixed solution of potassium ferrocyanide and citric acid, taking out after reaction, washing, repeating the process 1-3 times, freeze-drying to obtain PB / MoS2 / GO aerogel; the molar ratio of MoS2 and potassium ferrocyanide is 0.1-0.2:1-3; the molar ratio of MoS2 and ferric chloride is 0.1-0.2:1-3.

2. The method of preparing aerogel for the selective separation of radionuclide cesium from water according to claim 1, characterized by that, The concentration of polyacrylic acid aqueous solution in step S1 is 1 mg / mL, and the mass fraction of H2O2 solution is 30%.

3. The method of claim 1, wherein the aerogel is prepared by the method comprising the steps of: The high-temperature reaction in step S1 is carried out in a high-temperature hydrothermal kettle at 180℃, and the reaction time is 7-9 h.

4. The method of claim 1, wherein the aerogel is prepared by the method comprising the steps of: In the mixed solution of ferric chloride and citric acid, the molar ratio of FeCl3 and citric acid is 1:0.05; in the mixed solution of potassium ferrocyanide and citric acid, the molar ratio of potassium ferrocyanide and citric acid is 1:0.

05.

5. The method of claim 1, wherein the aerogel is prepared by the method comprising the steps of: In step S2, the reaction in the mixed solution of ferric chloride and citric acid is 1-1.5 h; the reaction in the mixed solution of potassium ferrocyanide and citric acid is 1-2 h.

6. Aerogel for selectively separating radionuclide cesium in water, prepared by the method according to any one of claims 1-5.

7. Application of aerogel for selectively separating radionuclide cesium in water, prepared by the method according to any one of claims 1-5, as an adsorbent in cesium ion selective adsorption.

8. Use according to claim 7, characterized in that: The pH range when adsorbing cesium ions is 2≤pH≤11.

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