Cesium ion sieve adsorbent and preparation method and application thereof

Abstract

The invention discloses a cesium ion sieve adsorbent as well as a preparation method and application thereof. The chemical formula of the cesium ion sieve adsorbent is (C3H10NO) 2.5 [Ga2. 5Ge1. 5S8]. 3H2O, the cesium ion sieve adsorbent is a cluster-based zeolite type metal sulfide with an SOD topological structure, has a three-dimensional anion frame structure, shows the characteristic of an ion sieve, and has selective adsorption capacity on Cs < + > ions in water. The adsorbent has excellent irradiation stability, cycling stability and acid-base stability, and has high adsorption capacity, rapid adsorption kinetics and good selective adsorption performance on Cs < + >. The invention also provides a cesium ion sieve adsorbent / gelatin composite nanofiber membrane which is prepared by taking a natural bio-based material gelatin as a base material through an electrostatic spinning technology, and the cesium ion sieve adsorbent / gelatin composite nanofiber membrane is integrated in a multi-stage membrane filtration system, so that efficient, continuous and dynamic treatment of various cesium-containing wastewater is realized. The problems that the solid phase is easy to lose and the solid-liquid separation is difficult in the using process of the powder adsorbent are solved, and the powder adsorbent has the characteristics of high efficiency, greenness, low price and recyclability.

Description

Technical Field

[0001] This application relates to a cesium ion sieve adsorbent, its preparation method, and its application, belonging to the field of adsorption material technology. Background Technology

[0002] 137 Cs is a hazardous radionuclide that often exists in aquatic environments as ions. Efficient capture from complex radioactive waste liquids... 137 Cs + This is an urgent need for the remediation of radioactive contamination and the reprocessing of spent fuel. Currently, the main methods for extracting and separating metal ions from water include: chemical precipitation, liquid membrane methods, biological treatment, adsorption, and ion exchange. Ion exchange has advantages such as simple operation, high efficiency, and no secondary pollution, and is considered a suitable method for treating Cs-containing water. + Ideally, waste liquids should be disposed of properly. However, many materials (such as ion exchange resins, zeolites, clays, titania silicates, and metal-organic frameworks) face problems such as low selectivity, limited capacity, or poor stability in practical applications. Especially K... + Na + Ca 2+ Mg 2+ Competing ions significantly affect the extraction of Cs by most adsorbents. + The performance of zeolite-like metal sulfide ion exchange materials is a new type of Cs. + The trapping agent, in its structure S 2- Highly polarizable, for Cs + They possess strong affinity. Furthermore, these materials offer advantages such as tunable pore size, high framework stability, and large specific surface area / pore volume, making them highly promising for efficient nuclide separation. However, existing zeolite-like metal sulfide ion exchange materials often contain large-sized protonated organic amines in their pore structures, leading to slow reaction kinetics and low adsorption capacity during ion exchange. Moreover, due to the inherent defects of inorganic crystalline / powder materials, their application in column and membrane separation has not yet been reported. Summary of the Invention

[0003] The purpose of this invention is to provide a highly efficient cesium adsorbent, its preparation method, and a method for separating cesium from aqueous solution, so as to solve the problems of low adsorption capacity, poor adsorption selectivity, easy loss of solid phase, and difficulty in solid-liquid separation in practical applications of traditional cesium adsorbents.

[0004] The Cs obtained by this invention + The adsorbent material exhibits extremely fast adsorption kinetics, good acid and alkali stability, radiation resistance, and can effectively overcome Cs. + The adsorption performance of adsorbents is affected by competing ions, especially Na+. +The adsorbent has significant drawbacks due to the influence of ions. The composite membrane based on this adsorbent and its preparation method are versatile and can effectively solve the problems of easy solid phase loss and difficult solid-liquid separation during the use of powder adsorbents.

[0005] According to a first aspect of this application, a cesium ion sieve adsorbent is provided, wherein the chemical formula of the cesium ion sieve adsorbent is: (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O; The cesium ion sieve adsorbent is a cluster-based zeolite-type metal sulfide with an SOD topology. It possesses a three-dimensional anionic framework structure and exhibits "ion sieve" properties, effectively targeting Cs in water. + Ions have selective adsorption capabilities.

[0006] The cesium ion sieve adsorbent provided in this application, under the induction of an organic amine molecular template, constructs a three-dimensional anionic framework with a regular pore structure from metal sulfur clusters.

[0007] According to a second aspect of this application, a method for preparing the above-mentioned cesium ion sieve adsorbent is provided, the method comprising: The raw materials containing sulfur powder, germanium source and gallium source are reacted in an organic amine solvent, excess solvent is removed, and the mixture is dried to obtain the cesium ion sieve adsorbent.

[0008] Optionally, the preparation method includes: S1: Using a certain amount of sulfur powder, germanium source and gallium source as raw materials, and a certain amount of isopropanolamine as solvent, the mixture is kept at a certain temperature for a certain time and then cooled to room temperature.

[0009] S2: The excess solvent is removed by repeated washing with water and ethanol, and the ion sieve adsorbent is obtained after drying.

[0010] Optionally, the germanium source is at least one of germanium oxide and elemental germanium.

[0011] Optionally, the gallium source is at least one of elemental gallium, gallium nitrate, gallium oxide, and gallium sulfide.

[0012] Optionally, the molar ratio of the sulfur powder, germanium source, and gallium source is (3.45~13.82):(5.2~2.08):(0.59~2.38).

[0013] Optionally, the solid-liquid ratio of the organic amine solvent to the raw material... m / V The ratio is 50:1 to 150:1.

[0014] Optionally, the reaction conditions are as follows: heating to 160-210 °C at a rate of 40-100 °C / h for 5-7 days, and cooling to room temperature at a rate of 6-24 °C / h.

[0015] Optionally, the organic amine solvent is selected from isopropanolamine.

[0016] Optionally, the reactants added are 222.1 mg S, 109.1 mg GeO2, 82.7 mg Ga, 192.7 mg S, and 3 mL isopropanolamine, heated to 190 °C at a heating rate of 80 °C / h, continuously heated at 190 °C for 6 days, and finally cooled to room temperature at a cooling rate of 40 °C / h.

[0017] According to a third aspect of this application, a cesium ion sieve adsorbent as described above is provided in Cs + Applications in adsorption materials.

[0018] Optionally, the cesium ion sieve adsorbent is used in the extraction of Cs. + Subsequently, the adsorbed Cs was treated with at least one of ammonium chloride, potassium chloride, and ammonium carbonate solutions. + The cesium ion sieve adsorbent is then used to achieve elution, recovery, and reuse of the cesium ion sieve adsorbent.

[0019] Optionally, in the presence of Na + K + Ca 2+ Mg 2+ In solutions with competing ions, cesium ion sieve adsorbents for Cs + The ions exhibit excellent selective adsorption capacity; they are effective for adsorbing actual ions generated in industrial production. 137 Cs liquid waste achieves a removal rate of over 90%.

[0020] According to a fourth aspect of this application, a nanofiber membrane is provided, the nanofiber membrane comprising a cesium ion sieve adsorbent and a polymer, wherein the cesium ion sieve adsorbent is selected from the above-mentioned cesium ion sieve adsorbents.

[0021] Optionally, the polymer is selected from gelatin.

[0022] According to a fifth aspect of this application, a method for preparing the above-mentioned nanofiber membrane is provided, the method comprising: The cesium ion sieve adsorbent was ball-milled, dispersed in an organic solvent containing a polymer, and electrospun to obtain the nanofiber membrane.

[0023] Optionally, the polymer is selected from gelatin.

[0024] Optionally, the mass ratio of the cesium ion sieve adsorbent to the polymer is 25% to 75%. Preferably, the electrospinning conditions are: 18~25 kV voltage, 0.5~1.5 mL / h feed rate, 12~25 cm receiving distance, and 50~150 rpm roller speed for electrospinning film formation.

[0025] Optionally, the spinning solution is electrospun into a cesium ion sieve adsorbent / gelatin fiber membrane under the conditions of 22 kV voltage, 0.5 mL / h feed rate, 16 cm receiving distance and 100 rpm drum speed.

[0026] Optionally, the organic solvent is selected from at least one of acetic acid, a buffer solvent for acetic acid, and hexafluoroisopropanol.

[0027] Optionally, the method for preparing the nanofiber membrane includes: ball milling a cesium ion sieve adsorbent at 400 rpm for 6 h to obtain particles of a suitable size, then fully dispersing it in an organic solvent of gelatin by stirring, with a mass ratio of cesium ion sieve adsorbent to gelatin of 3:1; and forming a cesium ion sieve adsorbent / gelatin nanofiber composite membrane by electrospinning under conditions of 22 kV voltage, 0.5 mL / h feed rate, 16 cm receiving distance, and 100 rpm roller speed.

[0028] According to a sixth aspect of this application, a multi-stage membrane filtration system is provided, the multi-stage membrane filtration system comprising the above-described nanofiber membrane.

[0029] Specifically, the multi-stage membrane filtration system includes the aforementioned nanofiber membrane, capable of treating Cs-containing substances in a continuous, dynamic filtration manner. + Wastewater, said wastewater includes Na + / Cs + Mixed wastewater or Cs + Polluting the river water.

[0030] Optionally, the components of the multi-stage membrane filtration system can be replaced and assembled to achieve dynamic removal of cesium-containing wastewater under different environments.

[0031] According to the seventh aspect of this application, an application of the above-mentioned nanofiber membrane in a cesium-containing water purification or radioactive wastewater treatment device is provided.

[0032] This invention presents a novel cesium ion sieve adsorbent / polymer composite nanofiber membrane prepared by electrospinning technology, which is then integrated into a multi-stage membrane filtration system to achieve efficient, continuous, and dynamic treatment of various cesium-containing wastewaters. The novel cesium ion sieve adsorbent provided by this invention can effectively overcome complex ion interference and achieve Cs… +The developed cesium ion sieve adsorbent / polymer composite nanofiber membrane exhibits high selective capture and solves the problems of solid phase loss and solid-liquid separation difficulties during the use of powder adsorbents. It is characterized by high efficiency, environmental friendliness, low cost, and recyclability. This adsorbent and composite membrane show promising application prospects in the treatment of nuclear industry wastewater and radioactive cesium-containing wastewater from nuclear power plants.

[0033] The beneficial effects that this application can produce include: (1) This invention provides a high-efficiency cesium ion sieve adsorbent and its preparation method; (2) The high-efficiency cesium ion sieve adsorbent prepared in this invention has a high efficiency for Cs + It has high selectivity in Na + K + Ca 2+ Mg 2+ Cs can still be selectively adsorbed in aqueous solutions where ions are in excess. + Ions, overcoming Cs + The adsorption performance of adsorbents is affected by competing ions, especially Na+. + Defects that are significantly affected by ions; (3) The high-efficiency cesium ion sieve adsorbent prepared in this invention effectively treats actual cesium ion sieve adsorbents. 137 Cs waste liquid, making the waste liquid 137 Cs activity concentration decreased by an order of magnitude; (4) The present invention has undergone systematic Cs + Adsorption experiments, including kinetics, radiation stability, acid and alkali resistance, cyclic stability, and dynamic membrane filtration adsorption-desorption experiments, confirmed that the prepared adsorbent is a highly efficient adsorbent for Cs. + The material has broad application prospects in the field of radioactive waste treatment.

[0034] (5) This invention provides a general composite method for high-efficiency cesium ion sieve adsorbents. The prepared composite nanofiber membrane can be effectively applied to membrane filtration systems to achieve efficient dynamic filtration of cesium-containing wastewater. Attached Figure Description

[0035] Figure 1 (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 The structural diagram and topological diagram of the S8·3H2O sample with clusters as nodes.

[0036] Figure 2 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5S8]·3H2O removes Cs + The adsorption amount fitting graph.

[0037] Figure 3 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O removes Cs + Adsorption kinetics diagram.

[0038] Figure 4 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 [S8]·3H2O has a wide pH range of effects on Cs + The removal rate and allocation coefficient diagram.

[0039] Figure 5 For raw and irradiated cesium ion sieve adsorbents (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 Removal of Cs from S8]·3H2O + Renderings.

[0040] Figure 6 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 [S8]·3H2O on Cs in the presence of different competing ions + The removal capability diagram.

[0041] Figure 7 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O treatment of real Cs-doped Cs + A diagram showing the capacity of a water body.

[0042] Figure 8 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O treatment of actual 137 Capacity diagram of Cs waste liquid.

[0043] Figure 9 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5[Ga 2.5 Ge 1.5 [S8]·3H2O undergoes five adsorption-desorption cycles to affect Cs + The removal rate graph.

[0044] Figure 10 This is a diagram of a multi-stage membrane filtration system.

[0045] Figure 11 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 Photographs and scanning electron microscope images of the S8·3H2O / gelatin fiber membrane.

[0046] Figure 12 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / Gelatin fiber membrane-filled membrane filter for Cs + The continuous dynamic adsorption curves (cesium / sodium mixed solution) were obtained using a three-stage separation system.

[0047] Figure 13 The cesium ion sieve adsorbent (C3H) after adsorption-elution regeneration 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / Gelatin fiber membrane-filled membrane filter for Cs + The secondary continuous dynamic adsorption curves (cesium / sodium mixed solution) were obtained using a three-stage separation system.

[0048] Figure 14 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / Gelatin fiber membrane-filled membrane filter for Cs + The continuous dynamic adsorption curve (from real river water containing cesium) was obtained using a four-stage separation system.

[0049] Figure 15 This is a schematic diagram of the preparation process of the cesium ion sieve adsorbent / gelatin composite nanofiber membrane of this application. Detailed Implementation

[0050] The present application is further illustrated below with reference to specific embodiments. The following descriptions are merely a few embodiments of the present application and are not intended to limit the present application in any way. Although the present application discloses preferred embodiments as follows, they are not intended to limit the present application. Any modifications or variations made by those skilled in the art without departing from the scope of the technical solution of the present application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

[0051] Unless otherwise specified, all reagents used are commercially available analytical grade, and raw materials are obtained through commercial channels.

[0052] Unless otherwise specified, the test conditions for the samples in the examples are as follows: Sample (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 X-ray diffraction data of the structure [S8]·3H2O were obtained using a SuperNova CCD X-ray diffractometer with a Mo target. Kα Radiation source ( λ = 0.71073 Å).

[0053] X-ray powder diffraction (XRD) phase analysis was performed on a Miniflex II X-ray diffractometer at 30 kV and 15 mA, using a Cu target. Kα Radiation source ( λ = 1.54178 Å).

[0054] Scanning electron microscopy (SEM) was performed on a JEOL JSM-6700F instrument.

[0055] Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) were performed on XSerise II and Thermo 7400 devices, respectively.

[0056] Figure 15 This is a schematic diagram of the preparation process of the cesium ion sieve adsorbent / gelatin composite nanofiber membrane of this application.

[0057] Example 1: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 Preparation and structural characterization of [S8]·3H2O 222.1 mg S, 109.1 mg GeO2, 82.7 mg Ga, 0.1927 g S, and 3 mL C3H9NO were sealed in a 25 mL polytetrafluoroethylene-lined reactor and heated to 190 °C at 80 °C / h for 6 consecutive days. The mixture was then cooled to room temperature at 40 °C / h. The resulting sample was filtered, washed successively with distilled water and ethanol, and air-dried to obtain pale yellow transparent dodecahedral crystals (C3H9NO). 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O.

[0058] Among them, (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 The crystal structure of [S8]·3H2O was obtained by single-crystal XRD. It belongs to... I The 3m space group belongs to the SOD topological type and has a three-dimensional zeolite-like metal sulfide framework formed by the shared corners of tetrahedral T2 clusters. Figure 1 Organic amine cations fill the three-dimensional channels.

[0059] Example 2: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 Isothermal adsorption model test of S8·3H2O (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O reacts with different initial Cs + Mix aqueous solutions of varying concentrations, according to V (Solution volume): m (Exchanger mass) = 1000 mL / g, shaken at room temperature for 10 h. After adsorption is complete, the supernatant and initial solution are collected, and Cs is determined by inductively coupled plasma mass spectrometry. + The concentration. Experimental results are as follows: Figure 2 Cs + Adsorbent material (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 The maximum adsorption capacity of S8·3H2O for cesium is 332.52 mg / g.

[0060] Example 3: Cesium ion sieve adsorbent (C3H) 10 NO)2.5 [Ga 2.5 Ge 1.5 S8]·3H2O on Cs + Dynamics test Cs + Adsorbent material (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O and a certain initial concentration of Cs + The aqueous solution was mixed, and the mixture was stirred at room temperature. V (Solution volume): m (Exchanger mass) = 1000 mL / g. Small amounts of the turbid solution were taken at regular intervals, filtered, and Cs were determined using inductively coupled plasma atomic emission spectrometry. + Concentration. (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O on Cs + The removal of particles can reach equilibrium within 1.5 minutes. Figure 3 ).

[0061] Example 4: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 Cs was extracted with S8·3H2O at different pH values. + Ability Test Cs + Adsorbent material (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O and Cs at different pH values + Solution mixing, according to V (Solution volume): m Under the condition of (exchange resin mass) = 1000 mL / g, the solution was shaken at room temperature for 10 h. After adsorption was complete, a small amount of the turbid liquid and the initial solution were taken after filtration, and Cs was determined by inductively coupled plasma atomic emission spectrometry. + The concentration. The results are as follows: Figure 4 As shown, Cs + Adsorbent material (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O can maintain its resistance to Cs within a pH range of approximately 3-12. + Removal activity.

[0062] Example 5: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 [S8]·3H2O removes Cs after irradiation + Ability Test Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O at 100 kGy γ and 200 kGy γ Materials irradiated with X-rays and Cs + Solution mixing, according to V (Solution volume): m (Exchanger mass) = 1000 mL / g, shaken at room temperature for 10 h. After adsorption is complete, the supernatant and initial solution are collected, and Cs is determined by inductively coupled plasma mass spectrometry. + The concentration. Test results are as follows: Figure 5 As shown, cesium ion sieve adsorbent (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O remains structurally stable after irradiation and has a positive effect on Cs. + The allocation coefficient remains high (>10) 4 The cesium ion sieve adsorbent provided in this application exhibits excellent radiation resistance and has undergone high-strength treatment. (mL / g) and removal rate (>96%). γ It maintained its stable structure and excellent Cs properties after X-ray irradiation. + Removal ability.

[0063] Example 6: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 Extraction and separation of Cs using S8]·3H2O in the presence of competing ions. + Selective ability test Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O reacts with different concentrations of Na + K + Ca 2+ Mg 2+ Mixing ion-soluble aqueous solutions, according to V (Solution volume):m (Exchanger mass) = 1000 mL / g, shaken at room temperature for 10 h. After the reaction is complete, the supernatant and the initial solution are taken and the ion concentrations are determined by inductively coupled plasma atomic emission spectrometry and atomic absorption spectrometry, respectively. The test results show that, under the competing ion Na+ conditions... + K + Ca 2+ Mg 2+ In the presence of excess amounts of cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O can still effectively remove Cs + And its removal of Cs + The ability is almost unaffected by an increase in the concentration of competing ions. Figure 6 ).

[0064] To evaluate the performance of cesium ion sieve adsorbent (C3H) in actual water samples 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O on Cs + The feasibility of ion removal, without any pretreatment, in the presence of low concentrations of Cs. + Further adsorption experiments were conducted on real samples of seawater, lake water, river water, and tap water containing the ions. Figure 7 Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 [S8]·3H2O showed good Cs performance in real water samples with high salinity, such as lake water, river water, and tap water. + Ion removal performance. Competitive ion experiments clearly confirmed the performance of (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O on Cs + Ions have a stronger affinity and can maintain their affinity for Cs in real, complex aquatic environments. + High adsorption capacity for ions.

[0065] Example 7: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O treatment of actual 137 Cs waste liquid (C3H) 10 NO)2.5 [Ga 2.5 Ge 1.5 S8·3H2O is used to treat two types of pollutants (pH = 8.35 or pH = 2.6) generated during industrial production by China National Nuclear Corporation's Atomic High Technology Co., Ltd. 137 Cs waste liquid. The initial active concentrations of the two waste liquids were 7.39 × 10⁻⁶ and 7.39 × 10⁻⁶, respectively. 4 Bq / mL and 1.41 × 10 4 Bq / mL. 5 mg, 10 mg, and 40 mg of cesium ion sieve adsorbent (C3H) were added. 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O was dissolved in 5 mL of solution at pH = 8.35 or pH = 2.6. 137 Mix the Cs waste liquid, shake for 6 hours, and then take the supernatant. γ Spectrometer Measurement 137 The activity of Cs. The test results show that the cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O to 137 The removal rate of Cs can reach 89.31%-91.15% ( Figure 8 ). This application provides Cs + Adsorbent material (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O exhibits excellent performance under actual working conditions. 137 Cs removal performance is a promising technology for industrial applications. 137 Cs adsorbent materials.

[0066] Example 8: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O adsorption-desorption cycle stability test Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O and 5000 mg / L Cs + Solution mixing, according to V (Solution volume): m (Exchanger mass) = 1000 mL / g, shake at room temperature for 12 h to fully adsorb Cs.+ Then, the mixture was shaken with a 1 mol / L ammonium chloride solution for 12 hours to fully elute the Cs adsorbed on the material. + After elution with 1 mol / L ammonium chloride solution, the Cs in the sample... + The sample was largely eluted. This sample was used as the material for the first round of adsorption cycles, and the product obtained after adsorption was used as the reactant for the desorption phase. Each cycle included two stages: adsorption and desorption. After the adsorption / desorption reaction was completed, the supernatant was used for inductively coupled plasma atomic emission spectrometry (ICP-AES). The solid sample, after washing and drying, was used in part for PXRD to confirm the framework stability of the compound, and in part for the next round of adsorption / desorption experiments. The solution used in the adsorption process was a 17.26 mg / L cesium chloride solution with a contact time of 12 hours; the solution used in the desorption process was a 1 mol / L ammonium chloride solution with a contact time of 12 hours. The solid sample used in each adsorption / desorption experiment was weighed and added to the corresponding amount of solution to ensure... V (Solution volume): m (Exchanger mass) = 1000 mL / g. Results of 5 rounds of cyclic experiments showed that the cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O exhibits excellent framework stability and Cs + Removal stability ( Figure 9 This application describes the cesium ion sieve adsorbent (C3H). 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8·3H2O has excellent recycling ability.

[0067] Example 9: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 Preparation of S8·3H2O / gelatin composite film The cesium ion sieve adsorbent (C3H) was processed using a ball mill. 10 NO) 2.5 [Ga 2.5 Ge 1.5 The particle size of [S8]·3H2O was reduced to a size suitable for electrospinning, so as to better disperse in the organic solvent hexafluoroisopropanol solution and uniformly adhere to the polymer surface. 2 g of GaGeS-1 was placed in a 50 mL zirconia jar and ball-milled with zirconia balls at 450 rpm for 6 hours to obtain ball-milled (C3H... 10 NO) 2.5 [Ga2.5 Ge 1.5 [S8]·3H2O. Then, 0.33 g, 0.66 g, and 0.99 g of gelatin were added to 10 mL of hexafluoroisopropanol solution to prepare gelatin solutions with concentrations of 0.33 g / 10 mL, 0.66 g / 10 mL, and 0.99 g / 10 mL, respectively. The solutions were stirred at room temperature for 12 hours to obtain completely dissolved, homogeneous solutions with a certain viscosity. 0.33 g of ball-milled (C3H)3H2O was added to the 0.99 g / 10 mL gelatin solution. 10 NO) 2.5 [Ga 2.5 Ge 1.5 Stirring with [S8]·3H2O for 24 hours to prepare (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 Spinning solution for S8]·3H2O / gelatin composite film.

[0068] Fill a 10 mL syringe with 10 mL of the prepared spinning solution and set up the electrospinning apparatus as shown in the figure below. Figure 10 Aluminum foil was attached to a roller collector rotating at 100 rpm. A 22G metal nozzle was used, with the nozzle 16 cm from the roller. Electrospinning was performed at a push rate of 0.5 mL / h under 22 kV DC voltage to uniformly deposit a mixture of gelatin and metal sulfide onto the aluminum foil. The resulting nanofiber membrane was named (C3H). 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / Gelatin composite film ( Figure 11 ).

[0069] Since gelatin lacks water stability, it needs to be cross-linked before it can be used in water treatment. Therefore, the water stability modification conditions for gelatin electrospun membranes were investigated before composite application. The prepared gelatin electrospun membranes were cut into 1 cm × 1 cm pieces and placed in a reactor containing 10 mL of 20% glutaraldehyde solution for glutaraldehyde vapor cross-linking experiments. To further investigate the effect of cross-linking time on the water stability of the gelatin electrospun membrane, gradient experiments were designed with times of 0 min, 10 min, 1 h, 5 h, 8 h, 12 h, and 14 h. This procedure was also applied to (C3H... 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / gelatin composite membrane to ensure its water stability.

[0070] Example 10: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 A three-stage membrane filtration device filled with S8·3H2O / gelatin composite membrane was used for the enrichment and extraction of Cs from Na / Cs mixed waste liquid. + Performance testing The prepared cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8·3H2O / gelatin membrane is used in the designed multi-stage membrane filtration system. The designed membrane filtration system is modular, allowing for flexible configuration of each functional unit to adapt to different application scenarios. Three fillers (C3H2O / gelatin membrane) are assembled in series. 10 NO) 2.5 [Ga 2.5 Ge 1.5 The functional module of S8·3H2O / gelatin membrane realizes the Cs in Na / Cs mixed wastewater. + Dynamic and efficient purification. When reaching (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 At the maximum throughput of [S8]·3H2O / gelatin film, the corresponding processing capacity reaches 3.58 L m. -2 (Figure 12). It is worth noting that despite the presence of excess Na... + Ions, but throughout the process, Cs + The removal rate consistently exceeded 99%, demonstrating (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 The rapid performance, ease of operation, and high selectivity of the [S8]·3H2O / gelatin film highlight its significant potential in practical applications.

[0071] Example 11: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 After elution and secondary adsorption, Cs in the Na / Cs mixed waste liquid was extracted by a three-stage membrane filtration device filled with S8·3H2O / gelatin composite membrane. + Performance testing Using 1 M NH4Cl can effectively elute adsorbed Cs + Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga2.5 Ge 1.5 S8]·3H2O / Cs on gelatin film + After elution and regeneration, (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / gelatin membrane can still be used for continuous selective enrichment of Cs in Na / Cs mixed wastewater. + (Figure 13). After regeneration (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / gelatin film showed almost the same effective treatment capacity as before, and at a treatment capacity of 3.58 Lm -2 At that time, for Cs + The removal rates all exceeded 99%. This proves that (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 [S8]·3H2O / Gelatin film can adsorb Cs + It was subsequently successfully washed away, regenerated, and reused.

[0072] Example 12: Cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 A four-stage membrane filtration device filled with S8]·3H2O / gelatin composite membrane in Cs-doped + Cs adsorbed in real river water + Performance testing The prepared cesium ion sieve adsorbent (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / gelatin membrane is used in the designed four-stage membrane filtration system, which is assembled in series with a membrane filter for pretreatment of solid impurities and three filters containing (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 The functional module of [S8]·3H2O / gelatin film realizes the true Cs doping. + Dynamic and efficient purification of river water. In the presence of various coexisting ions, (C3H... 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / gelatin film showed resistance to low Cs content +Continuous selective enrichment. At a throughput of 3.18 L / m³. 2 At that time, for Cs + The removal rate reached 99.49%. Figure 14 (C3H) 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O / gelatin membrane exhibits exceptional dynamic processing performance and can be applied to membrane filters to achieve complex Cs-containing processes. + It provides efficient and convenient wastewater purification.

[0073] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A cesium ion sieve adsorbent, characterized in that, The chemical formula of the cesium ion sieve adsorbent is: (C3H 10 NO) 2.5 [Ga 2.5 Ge 1.5 S8]·3H2O; The cesium ion sieve adsorbent is a cluster-based zeolite-type metal sulfide with an SOD topology and a three-dimensional anionic framework structure.

2. The preparation method of the cesium ion sieve adsorbent according to claim 1, characterized in that, The preparation method includes: The raw materials containing sulfur powder, germanium source and gallium source are reacted in an organic amine solvent, excess solvent is removed, and the mixture is dried to obtain the cesium ion sieve adsorbent.

3. The preparation method according to claim 2, characterized in that, The germanium source is at least one of germanium oxide and elemental germanium. And / or, the gallium source is at least one of elemental gallium, gallium nitrate, gallium oxide, and gallium sulfide; Preferably, the molar ratio of the sulfur powder, germanium source, and gallium source is (3.45~13.82):(5.2~2.08):(0.59~2.38); Preferably, the reaction conditions are as follows: heating to 160-210°C at a rate of 40-100 °C / h for 5-7 days, and cooling to room temperature at a rate of 6-24 °C / h. Preferably, the organic amine solvent is selected from isopropanolamine.

4. The cesium ion sieve adsorbent according to claim 1 in Cs + Applications in adsorption materials.

5. The application according to claim 4, characterized in that, The cesium ion sieve adsorbent is used in the extraction of Cs. + Subsequently, the adsorbed Cs was treated with at least one of ammonium chloride, potassium chloride, and ammonium carbonate solutions. + The cesium ion sieve adsorbent is then used to achieve elution, recovery, and reuse of the cesium ion sieve adsorbent.

6. A nanofiber membrane, characterized in that, The nanofiber membrane comprises a cesium ion sieve adsorbent and a polymer, wherein the cesium ion sieve adsorbent is selected from the cesium ion sieve adsorbent described in claim 1; Preferably, the polymer is selected from gelatin.

7. The method for preparing the nanofiber membrane according to claim 6, characterized in that, The preparation method includes: The cesium ion sieve adsorbent was ball-milled, dispersed in an organic solvent containing a polymer, and electrospun to obtain the nanofiber membrane. Preferably, the polymer is selected from gelatin.

8. The preparation method according to claim 7, characterized in that, The mass ratio of the cesium ion sieve adsorbent to the polymer is 25%~75%; Preferably, the electrospinning conditions are: 18~25 kV voltage, 0.5~1.5 mL / h feed rate, 12~25 cm receiving distance, and 50~150 rpm roller speed for electrospinning film formation.

9. A multi-stage membrane filtration system, characterized in that, The multi-stage membrane filtration system comprises the nanofiber membrane of claim 6.

10. The application of the nanofiber membrane according to claim 6 in a device for purifying cesium-containing water or treating radioactive wastewater.

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