Preparation method of tungsten-doped tin sulfide composite adsorbent and rubidium adsorption material

Abstract

The invention relates to a preparation method of a tungsten-doped tin sulfide composite adsorbent and a rubidium adsorption material, and the preparation method comprises the following steps: (S1) a synthetic reaction step: mixing KCL, W, Sn and S with a proper amount of deionized water according to a molar ratio of (8-16): (0.5-2): (4-8): (10-20), and reacting to obtain a first product; and (S2) washing: washing and drying the first product to obtain the tungsten-doped tin sulfide. And (S3) magnetism endowing: mixing the tungsten-doped tin sulfide and ferroferric oxide according to a molar ratio of (5-15): 1, adding a proper amount of deionized water, mixing, then adding 0.5-2.0 g of sodium alginate, uniformly mixing, and removing bubbles to obtain a mixed solution. And (S4) a cross-linking reaction step: spraying the mixed solution into a barium chloride solution with the mass concentration of 1-10% for reaction, and washing to obtain the tungsten-doped tin sulfide composite adsorbent. The tungsten-doped tin sulfide composite adsorbent disclosed by the invention has the properties of large adsorption capacity, high rate and selectivity on rubidium, and is easily and quickly separated from an adsorption solution.

Description

[0001] This application claims the priority of a Chinese patent application with the application number 202410574256.7, the application date of May 10, 2024, and the invention title of "Preparation Method of Tungsten-Doped Tin Sulfide Composite Adsorbent and Rubidium Adsorption Material". Technical Field

[0002] The present invention relates to the technical field of rubidium adsorption materials, and particularly to a preparation method of a tungsten-doped tin sulfide composite adsorbent. Background Art

[0003] Rubidium is a silver-white light metal, soft and waxy. Its chemical properties are more active than those of potassium. The unique properties of rubidium and its compounds, such as the high stability of radiation energy frequency, easy ionization, excellent optoelectronic properties, and strong chemical activity, are widely used in fields such as national defense, aerospace, biomedicine, and energy. The reserves of rubidium in brine are huge, but the concentration is low. Brine is mainly used for extracting lithium, potassium, magnesium, etc. There is no large-scale production of extracting rubidium from brine, resulting in waste of resources. Therefore, efficiently extracting rubidium resources from brine is of great significance for the comprehensive development of brine.

[0004] The technologies for extracting rubidium from brine mainly include precipitation method, extraction method, and ion exchange method. Inorganic ion exchange adsorbents have good stability, continuous operability, and acid resistance, and have gradually become a research hotspot in the fields of liquid mineral resource extraction, radioactive element removal, and wastewater harmless treatment.

[0005] Currently, the materials for inorganic rubidium adsorption mainly include natural ores, heteropolyacid salts, and Prussian blue and its analogs. Among them, the adsorption capacity of heteropolyacid salt ion adsorbents is generally low, the adsorption rate is slow, and the selectivity is poor, and they have not yet entered actual industrial applications. Natural clay adsorbents are inexpensive, safe, and easy to obtain, but the adsorption capacity of this type of adsorbent is generally low, and the selectivity and stability are poor, resulting in poor industrial application prospects. Prussian blue and its analog adsorbents have good selectivity for rubidium ions in complex system solutions, but there are problems such as low adsorption capacity, slow adsorption rate, and difficult desorption, which limit their large-scale industrial applications.

[0006] Therefore, for the separation and extraction of rubidium in liquid minerals such as salt lake brine, underground brine, and geothermal water, developing an adsorbent with a fast adsorption rate, high capacity, and good selectivity is a prerequisite for promoting the industrial production of extracting rubidium resources from brine.

[0007] The purpose of the present invention is to solve the problem that the existing rubidium adsorbents have low adsorption efficiency, which affects the large-scale industrial production of extracting rubidium from brine. Summary of the Invention

[0008] To solve the above problems, the present invention provides a method for preparing a tungsten-doped tin sulfide composite adsorbent, including a synthesis reaction step S1, in which anhydrous potassium chloride, tungsten powder, tin powder, and sulfur powder are mixed in a molar ratio of 8-16:0.5-2:4-8:10-20, and then 0.5-2 mL of deionized water is added and mixed evenly. A synthesis reaction is carried out at a temperature of 150-260 °C. After sufficient reaction, a first product is obtained. A washing step S2, in which the first product is washed successively with deionized water, absolute ethanol, carbon disulfide, and absolute ethanol, and then dried to obtain tungsten-doped tin sulfide.

[0009] A magnetic property endowment step S3, in which tungsten-doped tin sulfide and iron tetroxide are mixed in a molar ratio of 5-15:1, 20-100 g of deionized water is added and mixed evenly, and then 0.5-2.0 g of sodium alginate is added and mixed evenly. After ultrasonic treatment to remove bubbles, a mixed solution is obtained. A cross-linking reaction step S4, in which the mixed solution is sprayed into a barium chloride solution with a mass concentration of 1-10% for cross-linking reaction. After sufficient reaction, washing is carried out to obtain a tungsten-doped tin sulfide composite adsorbent.

[0010] The tungsten-doped tin sulfide composite adsorbent synthesized by the present invention has excellent adsorption properties such as a large adsorption capacity, a fast adsorption rate, and good selectivity for rubidium resources in complex aqueous solution systems such as underground brine, geothermal water, and salt lake brine, and has an adsorption capacity and adsorption rate equivalent to those of powder materials. When in use, rapid separation between the adsorbent and the adsorption liquid can be achieved by applying an external magnetic field, which is convenient for subsequent operations. The excellent adsorption properties and fast separation operation of the tungsten-doped tin sulfide composite adsorbent in the present invention facilitate the large-scale industrial production of extracting rubidium from brine. The present invention has simple operation, is quickly available, has mild experimental conditions, is environmentally friendly, and can achieve large-scale production.

[0011] Preferably, in the synthesis reaction step S1, the synthesis reaction time is 12-72 h, and the synthesis reaction temperature is 170-240 °C.

[0012] Preferably, in the synthesis reaction step S1, the synthesis reaction temperature is 200 °C.

[0013] Preferably, in the synthesis reaction step S1, the molar ratio of anhydrous potassium chloride, tungsten powder, tin powder, and sulfur powder is 12:1.5:6:18.

[0014] Preferably, in the synthesis reaction step S1, the addition amount of deionized water is 1.5 mL.

[0015] Preferably, in the washing step S2, the cross-linking reaction time is 36-60 h.

[0016] Preferably, in the magnetic property endowment step S3, the molar ratio of tungsten-doped tin sulfide and iron tetroxide is 10:1.

[0017] Preferably, in the magnetic imparting step S3, the addition amount of sodium alginate is 1.0 g.

[0018] Preferably, in the cross-linking reaction step S4, the mass concentration of the barium chloride solution is 5%.

[0019] A rubidium adsorption material for adsorbing rubidium ions from rubidium-containing brine, wherein the rubidium adsorption material adopts the tungsten-doped tin sulfide composite adsorbent described in any one of the above. Description of the Drawings

[0020] Figure 1 . Flow chart of the preparation method of the tungsten-doped tin sulfide composite adsorbent; Figure 2 . SEM electron microscope scanning image and EDS element distribution map of tungsten-doped tin sulfide; Figure 3 . Adsorption performance graph of tungsten-doped tin sulfide as an adsorbent for rubidium ions; Figure 4 . Linear fitting graphs of pseudo-first-order and pseudo-second-order adsorption kinetics of tungsten-doped tin sulfide as an adsorbent for rubidium ions; Figure 5 . Physical image, SEM electron microscope scanning image and EDS element distribution map of the tungsten-doped tin sulfide composite adsorbent; Figure 6 . Adsorption performance graph of the tungsten-doped tin sulfide composite adsorbent for rubidium ions. Detailed Embodiments

[0021] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] As Figure 1 shown, the preparation method of tungsten-doped tin sulfide includes a synthesis reaction step S1, in which anhydrous potassium chloride, tungsten powder, tin powder and sulfur powder are mixed in a molar ratio of 8-16:0.5-2:4-8:10-20, and then added into a stainless steel autoclave with a polytetrafluoroethylene lining. Then, 0.5-2 mL of deionized water is added and mixed evenly. After sealing the autoclave, it is placed in an oven at 150-260 °C for 12-72 h to allow the materials to fully undergo a synthesis reaction to obtain a first product.

[0023] Among them, the molar ratio of anhydrous potassium chloride, tungsten powder, tin powder and sulfur powder is preferably 12:1.5:6:18, and the first product synthesized within this range has the best adsorption performance for rubidium ions.

[0024] In other embodiments, potassium carbonate can also be used instead of anhydrous potassium chloride.

[0025] Among them, the addition amount of deionized water in the synthesis reaction is preferably 1.5 - 2.0 mL, and the optimal addition amount is 1.5 mL. If the addition amount of deionized water is less than 0.5 mL, the synthesis reaction will not be complete, resulting in a decrease in the adsorption capacity of the adsorbent.

[0026] The temperature of the synthesis reaction is preferably 170 - 240 °C, and the optimal reaction temperature is 200 °C. If the temperature is lower than 150 °C or higher than 260 °C, the reaction will not be complete, causing a decrease in the adsorption capacity of the adsorbent.

[0027] The reaction time for the material synthesis reaction is preferably 36 - 60 h, and the optimal reaction time is 48 h. If the reaction time is less than 12 h, due to insufficient reaction time, the adsorption performance of the produced adsorbent will be poor. If the reaction time is greater than 72 h, although the reaction time is sufficient and the performance of the synthesized product is outstanding, it is not conducive to energy conservation and environmental protection.

[0028] In the washing step S2, the first product is washed successively with deionized water, absolute ethanol, carbon disulfide, and absolute ethanol, and then placed in an oven and dried at 80 °C for 4 - 10 h to obtain tungsten-doped tin sulfide (KWS).

[0029] The drying time of the first product is preferably 5 - 8 h, and the optimal drying time is 6 h, with a drying temperature of 80 °C. Since the boiling point of absolute ethanol is 78.3 °C, setting the drying temperature at 80 °C can completely evaporate the absolute ethanol.

[0030] When washing the first product, it is first washed three times with deionized water. The purpose is to remove the unreacted anhydrous potassium chloride in the product, and washing three times is to completely remove the potassium chloride.

[0031] Then, it is washed twice with absolute ethanol. The purpose is to remove the water in the first product to prepare for the subsequent washing with carbon disulfide. If the first product contains water, stratification will occur during washing with carbon disulfide, resulting in incomplete washing of the first product and waste.

[0032] It is then washed once with carbon disulfide. The purpose of washing with carbon disulfide is to remove the unreacted sulfur powder in the first product.

[0033] Finally, it is washed twice with absolute ethanol. On the one hand, it is to remove the residual carbon disulfide from the previous washing, and on the other hand, the first product is easier to dry after being washed with absolute ethanol.

[0034] Potassium tungsten-doped tin sulfide (KWS) is a multi-layered structure containing potassium (K), tungsten (W), tin (Sn), and sulfur (S). Among them, tin sulfide (Sn-S) constitutes the main framework of the layered structure. Potassium ions, as cations, exist between the layered structures and are used to balance the charge. The doping of tungsten causes corresponding changes in the bond lengths of the Sn-S framework structure.

[0035] The molecular formula of potassium tungsten-doped tin sulfide is: K2WxSn3S 7-x or K2WxSn4S 9-x . In the molecular formula, x is the stoichiometric coefficient of tungsten metal, x = 0.15 - 0.5, and 7 - x, 9 - x are the stoichiometric coefficients of Sn.

[0036] Therefore, potassium tungsten-doped tin sulfide can be used as an adsorbent and has excellent adsorption properties such as a large adsorption capacity, a fast adsorption rate, and good selectivity for rubidium resources in complex aqueous solution systems such as underground brine, geothermal water, and salt lake brine, and has an adsorption capacity and adsorption rate comparable to those of powder materials.

[0037] The description of the adsorption effect of potassium tungsten-doped tin sulfide as an adsorbent can be found in detail in the examples.

[0038] The following is the preparation method of the potassium tungsten-doped tin sulfide composite adsorbent. The method is to add a magnetic endowment step on the basis of the preparation method of potassium tungsten-doped tin sulfide, specifically as follows: Magnetic endowment step S3: Mix potassium tungsten-doped tin sulfide and iron oxide in a molar ratio of 5 - 15:1, add them to a sealed conical flask containing 20 - 100 g of deionized water, and stir well to mix evenly. Then add 0.5 - 2.0 g of sodium alginate and stir until the sodium alginate is evenly dispersed. Then, remove the bubbles in the system by ultrasonic treatment for 10 min to obtain a mixed solution.

[0039] The molar ratio of potassium tungsten-doped tin sulfide to iron oxide is preferably 8 - 12:1, and most preferably 10:1. If the molar ratio is higher than 12:1, the proportion of iron oxide in the system is high, which will lead to a decrease in the adsorption performance of the adsorbent. If the molar ratio is lower than 8:1, the microspheres in the subsequent product will have weak magnetism, resulting in poor separation effect between the adsorbent and the adsorption liquid.

[0040] The mass ratio of deionized water to sodium alginate in the sealed conical flask is preferably 40 - 60:1.0 - 1.5, and the most preferred mass ratio is 50:1. The mass ratio of deionized water to sodium alginate directly affects the granulation effect when the mixed solution is sprayed by the atomizing spray device. If the viscosity of the mixed solution is low, the strength of the microspheres in the subsequent product will be too low, which is not conducive to subsequent operations. If the viscosity of the mixed solution is high, it will be difficult to spray and granulate with the atomizing spray device.

[0041] In the cross-linking reaction step S4, the mixed solution is evenly sprayed into a barium chloride (BaCl2) solution with a mass concentration of 1-10% through an atomizing spray device for cross-linking reaction and then molded to obtain magnetic microspheres. After sufficient reaction, washing is carried out to obtain a magnetic tungsten-doped tin sulfide composite (MKWS) adsorbent.

[0042] The preferred concentration of the barium chloride solution is 3-7%, and the most preferred is 5%. If the concentration of the barium chloride solution is too low, the cross-linking reaction is incomplete, resulting in low microsphere strength. If the concentration of the barium chloride solution is higher than 5%, although microspheres with a certain strength can be obtained, it is not conducive to energy conservation and environmental protection.

[0043] The tungsten-doped tin sulfide composite adsorbent is a kind of magnetic microsphere, which not only has the adsorption performance of tungsten-doped tin sulfide as an adsorbent, but also has magnetism. When used as an adsorbent, rapid separation between the adsorbent and the adsorption liquid can be achieved through an external magnetic field, facilitating subsequent operations.

[0044] Details of the adsorption effect of tungsten-doped tin sulfide as an adsorbent are shown in the examples.

[0045] Example 1 In this example, tungsten-doped tin sulfide was synthesized by the hydrothermal method.

[0046] KCl (12 mmol), W (1.5 mmol), Sn (6 mmol), and S (18 mmol) were respectively added into a 100 mL stainless steel hydrothermal reaction kettle, and then 1.5 mL of deionized water was added. After sealing, it was placed in a vacuum drying oven at 200 °C for 48 h. After the reaction ended, it was naturally cooled to room temperature. The first product was washed thoroughly with deionized water, absolute ethanol, carbon disulfide, and absolute ethanol in sequence, and then dried in an oven at 80 °C for 6 h. Finally, tungsten-doped tin sulfide (KWS) was obtained.

[0047] Figure 2 In a and b are SEM characterization diagrams of tungsten-doped tin sulfide. It can be seen from the figure that the material has a multi-layered structure with obvious lamellar characteristics. c-h are EDS diagrams of the uniform distribution of elements after tungsten-doped tin sulfide adsorbs rubidium.

[0048] 1 g / L of the synthesized tungsten-doped tin sulfide was added to a rubidium chloride solution with an initial concentration of 55 mg / L. The adsorption process is as Figure 3 shown in (b). The adsorption process reaches the adsorption equilibrium in about 5 s, showing a very fast adsorption rate.

[0049] 0.5 g / L of tungsten-doped tin sulfide was added to rubidium chloride solutions with initial concentrations of 50, 75, 150, 100, 200, 300, 500, and 600 mg / L, respectively. The mixture was shaken at a constant temperature for 60 min at room temperature. After centrifugal solid-liquid separation, the rubidium ion concentration was measured using ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer). The results are as Figure 3 shown in (a). It can be seen that the maximum adsorption capacity of tungsten-doped tin sulfide as an adsorbent for rubidium ions is approximately 182.89 mg / g.

[0050] From Figure 4 it can be clearly seen that the adsorption behavior of tungsten-doped tin sulfide for rubidium ions is more in line with the pseudo-second-order fitting equation, which also indicates from another perspective that the adsorption mechanism of tungsten-doped tin sulfide for rubidium ions is chemical adsorption ion exchange.

[0051] Na + coexisting with Rb + , K + , Ca 2+ and Mg 2+ ions are commonly present in salt lake water, geothermal brine, and groundwater. Therefore, in this invention, simulated Qarhan Salt Lake brine was used to conduct competitive adsorption experiments to explore the selectivity of tungsten-doped tin sulfide. Among the high-concentration competitive ions, the distribution coefficient of Rb + is 10828.89 mL / g. It can be seen that tungsten-doped tin sulfide has a strong affinity and adsorption selectivity for Rb + , and it also has a large adsorption capacity and a fast adsorption rate.

[0052] Example 2 This example is about the preparation of a tungsten-doped tin sulfide composite adsorbent.

[0053] Tungsten-doped tin sulfide and iron oxide were added to a sealed conical flask containing 50 g of deionized water at a molar ratio of 10:1. After thorough stirring, 1.0 g of sodium alginate was added and stirred until it was evenly dispersed. After ultrasonic treatment for 10 min to remove the air bubbles in the system, a mixed solution was obtained. Then the mixed solution was transferred to an atomizing spray device, and the mixed solution was evenly sprayed into a 5% BaCl2 solution using the atomizing spray device. After cross-linking reaction, magnetic microspheres were formed. They were washed and soaked repeatedly with deionized water to remove the cross-linking solution, and finally a magnetic tungsten-doped tin sulfide composite (MKWS) adsorbent was obtained.

[0054] Figure 5In Figure a, it is a physical picture of the tungsten-doped tin sulfide composite adsorbent. Figures b and c are SEM characterization pictures of the tungsten-doped tin sulfide composite adsorbent. The rest are EDS elemental analysis pictures of the uniform distribution after the tungsten-doped tin sulfide composite adsorbent adsorbs rubidium elements. It can be seen from the figures that tungsten-doped tin sulfide (KWS) is successfully coated and evenly dispersed in the coating material.

[0055] 1 g / L of the synthesized tungsten-doped tin sulfide composite adsorbent was added to rubidium chloride solutions with initial concentrations of 50, 100, 150, 200, 250, 300, 500, and 600 mg / L respectively. After constant-temperature oscillation at room temperature for 60 min, the liquid was taken and the rubidium ion concentration was measured by ICP-OES. The results are as Figure 6 shown in (a). It can be known that the maximum adsorption capacity of the tungsten-doped tin sulfide composite adsorbent for rubidium ions is about 171.06 mg / g.

[0056] 1 g / L of the synthesized tungsten-doped tin sulfide composite adsorbent was added to a rubidium chloride solution with an initial concentration of 10 mg / L. The results are as Figure 6 shown in (b). The adsorption process of the tungsten-doped tin sulfide composite adsorbent for rubidium can reach the adsorption equilibrium within 10 min. It can be known that the tungsten-doped tin sulfide composite adsorbent shows strong affinity and adsorption selectivity for rubidium, and has a large adsorption capacity and a fast adsorption rate.

[0057] The adsorption performance of tungsten-doped tin sulfide as an adsorbent for rubidium in Example 1 is compared and explained through the following comparative examples.

[0058] Comparative Example 1 In this comparative example, tungsten-doped tin sulfide was prepared using a reactant molar ratio different from that in Example 1.

[0059] KCl (6 mmol), W (3 mmol), Sn (6 mmol), and S (18 mmol) were respectively added to a 100 mL stainless steel hydrothermal reaction kettle with a polytetrafluoroethylene liner, and then 1.5 mL of deionized water was added and sealed tightly. Then it was placed in a vacuum drying oven at 200 °C for 48 h. After the reaction ended, it was naturally cooled to room temperature. The product was thoroughly washed with deionized water, anhydrous ethanol, carbon disulfide, and anhydrous ethanol, and then dried in an oven at 80 °C for 6 h. Finally, tungsten-doped tin sulfide (KWS-1) was obtained. 0.5 g / L of the synthesized tungsten-doped tin sulfide (KWS-1) was added to rubidium chloride solutions with initial concentrations of 20, 50, 100, 200, 300, 500, and 600 mg / L respectively. After constant-temperature oscillation at room temperature for 60 min, the solid and liquid were separated by centrifugation, and the rubidium ion concentration was measured by ICP-OES.

[0060] The maximum adsorption capacity of the tungsten-doped tin sulfide (KWS-1) prepared in this comparative example as an adsorbent for rubidium ions was measured to be approximately 114.7 mg / g. It can be seen that the adsorption capacity of the tungsten-doped tin sulfide (KWS-1) as an adsorbent is much lower than that of the tungsten-doped tin sulfide (KWS) prepared in Example 1 as an adsorbent. It can be known that the molar ratio of each reactant added in Example 1 is the most preferable.

[0061] Comparative Example 2 In this comparative example, tungsten-doped tin sulfide was prepared using a different amount of deionized water added compared to Example 1.

[0062] KCl (12 mmol), W (1.5 mmol), Sn (6 mmol), and S (18 mmol) were respectively added to a 100 ml stainless steel hydrothermal reactor, and then 0.5 mL of deionized water was added and sealed tightly. Then it was placed in a vacuum drying oven at 200 °C for 48 h, and after the reaction ended, it was naturally cooled to room temperature. The product was washed thoroughly with deionized water, absolute ethanol, carbon disulfide, and absolute ethanol, and then dried in an oven at 80 °C for 6 h to finally obtain tungsten-doped tin sulfide (KWS-2). 0.5 g / L of the synthesized tungsten-doped tin sulfide (KWS-2) was added to rubidium chloride solutions with initial concentrations of 20, 50, 100, 200, 300, 500, and 600 mg / L respectively. After constant temperature oscillation at room temperature for 60 min, centrifugation was used to separate the solid and liquid phases, and the rubidium ion concentration was determined by ICP-OES.

[0063] The maximum adsorption capacity of the tungsten-doped tin sulfide (KWS-2) prepared in this comparative example as an adsorbent for rubidium ions was measured to be approximately 98.56 mg / g. This adsorption capacity is much lower than that of the tungsten-doped tin sulfide (KWS) prepared in Example 1 as an adsorbent. It can be seen that the amount of deionized water added in Example 1 is the most preferable.

[0064] Comparative Example 3 Tungsten-doped tin sulfide was prepared using a reaction temperature setting different from that in Example 1.

[0065] KCl (12 mmol), W (1.5 mmol), Sn (6 mmol), and S (18 mmol) were respectively added into a 100 mL stainless steel hydrothermal reactor with a PTFE liner. Then 1.5 mL of deionized water was added, and it was sealed tightly. After that, it was placed in a vacuum drying oven at 150 °C for 48 h. After the reaction ended, it was naturally cooled to room temperature. The product was washed thoroughly with deionized water, absolute ethanol, carbon disulfide, and absolute ethanol, and then dried in an oven at 80 °C for 6 h. Finally, tungsten-doped tin sulfide (KWS-3) was obtained. 0.5 g / L of the synthesized tungsten-doped tin sulfide (KWS-3) was added to rubidium chloride solutions with initial concentrations of 20, 50, 100, 200, 300, 500, and 600 mg / L respectively. After constant temperature oscillation at room temperature for 60 min, centrifugation was used to separate the solid and liquid phases, and an ICP-OES was used to measure the rubidium ion concentration.

[0066] It was measured that the maximum adsorption capacity of the tungsten-doped tin sulfide (KWS-3) prepared in this comparative example as an adsorbent for rubidium ions was approximately 88.01 mg / g. This adsorption capacity was much lower than that of the tungsten-doped tin sulfide (KWS) prepared in Example 1 as an adsorbent. It can be seen that the reaction temperature set in Example 1 was the most preferred.

[0067] Comparative Example 4 Tungsten-doped tin sulfide was prepared by setting a reaction duration different from that in Example 1.

[0068] KCl (12 mmol), W (1.5 mmol), Sn (6 mmol), and S (18 mmol) were respectively added into a 100 mL stainless steel hydrothermal reactor. Then 1.5 mL of deionized water was added, and it was sealed tightly. After that, it was placed in a vacuum drying oven at 150 °C for 12 h. After the reaction ended, it was naturally cooled to room temperature. The product was washed thoroughly with deionized water, absolute ethanol, carbon disulfide, and absolute ethanol, and then dried in an oven at 80 °C for 6 h. Finally, tungsten-doped tin sulfide (KWS-4) was obtained. 0.5 g / L of the synthesized tungsten-doped tin sulfide (KWS-4) was added to rubidium chloride solutions with initial concentrations of 20, 50, 100, 200, 300, 500, and 600 mg / L respectively. After constant temperature oscillation at room temperature for 60 min, centrifugation was used to separate the solid and liquid phases, and an ICP-OES was used to measure the rubidium ion concentration.

[0069] It was measured that the maximum adsorption capacity of the tungsten-doped tin sulfide (KWS-4) prepared in this comparative example as an adsorbent for rubidium ions was approximately 58.32 mg / g. It can be seen that this adsorption capacity was much lower than that of the tungsten-doped tin sulfide (KWS) prepared in Example 1 as an adsorbent. It can be seen that the reaction time set in Example 1 was the most preferred.

[0070] The adsorption performance of the tungsten-doped tin sulfide composite adsorbent in Example 2 is compared and described through comparative examples below.

[0071] Comparative Example 5 A tungsten-doped tin sulfide composite adsorbent was prepared using a molar ratio of tungsten-doped tin sulfide to iron oxide that was different from that in Example 2.

[0072] Tungsten-doped tin sulfide and iron oxide were added to a sealed conical flask containing 50 g of secondary water at a molar ratio of 15:1. After thorough stirring, 1.0 g of sodium alginate was added, and then stirring was continued until the sodium alginate was evenly dispersed. After ultrasonic treatment for 10 min to remove the air bubbles in the system, a preliminary solution was obtained. Then the mixture was transferred to an atomizing spray device. The preliminary solution was evenly sprayed into a 5% BaCl2 solution using the spray atomizing device, and a magnetic tungsten-doped tin sulfide composite (MKWS-1) adsorbent was obtained after crosslinking and forming.

[0073] Finally, compared with the tungsten-doped tin sulfide composite (MKWS) adsorbent prepared in Example 2, the tungsten-doped tin sulfide composite (MKWS-1) adsorbent prepared in this comparative example had similar adsorption performance. However, due to the lower addition amount of iron oxide, the microspheres had a weak response to the magnetic field and could not achieve a rapid separation effect. It can be seen that the molar ratio of tungsten-doped tin sulfide to iron oxide selected in Example 2 was the most optimal.

[0074] Comparative Example 6 A tungsten-doped tin sulfide composite adsorbent was prepared using a sodium alginate addition amount that was different from that in Example 2.

[0075] Tungsten-doped tin sulfide and iron oxide were added to a sealed conical flask containing 50 g of secondary water at a molar ratio of 15:1. After thorough stirring, 0.5 g of sodium alginate was added, and then stirring was continued until the sodium alginate was evenly dispersed. After ultrasonic treatment for 10 min to remove the air bubbles in the system, a preliminary solution was obtained. Then the mixture was transferred to an atomizing spray device. The preliminary solution was evenly sprayed into a 5% BaCl2 solution using the spray atomizing device, and a magnetic tungsten-doped tin sulfide composite (MKWS-2) adsorbent was obtained after crosslinking and forming.

[0076] Finally, compared with the tungsten-doped tin sulfide composite (MKWS) adsorbent prepared in Example 2, the tungsten-doped tin sulfide composite (MKWS-2) adsorbent prepared in this comparative example had microspheres that did not form due to the too dilute viscosity of the preliminary solution, and subsequent experiments could not be carried out. It can be seen that the sodium alginate addition amount selected in Example 2 was the most optimal.

[0077] In summary, the tungsten-doped tin sulfide composite adsorbent synthesized in the present invention has excellent adsorption properties for rubidium resources in complex aqueous solution systems, such as large adsorption capacity, fast adsorption rate, and good selectivity, and has an adsorption capacity and adsorption rate comparable to those of powder materials. During use, rapid separation between the adsorbent and the adsorption liquid can be achieved by applying an external magnetic field, facilitating subsequent operations. It is convenient to scale up the extraction of rubidium from brine for industrial production.

[0078] It should be noted that the above embodiments illustrate the present invention rather than limit the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims.

Claims

1. Preparation method of tungsten-doped tin sulfide composite adsorbent, characterized in that, Including, Synthesis reaction step (S1): Mix anhydrous potassium chloride, tungsten powder, tin powder, and sulfur powder in a molar ratio of 8 - 16:0.5 - 2:4 - 8:10 - 20, add 0.5 - 2 mL of deionized water and mix evenly, and conduct a synthesis reaction at a temperature of 150 - 260 °C. After sufficient reaction, a first product is obtained; Washing step (S2): Wash the first product successively with deionized water, absolute ethanol, carbon disulfide, and absolute ethanol, and obtain tungsten-doped tin sulfide after drying; Magnetic property endowment step (S3): Mix tungsten-doped tin sulfide and iron tetroxide in a molar ratio of 5 - 15:1, add 20 - 100 g of deionized water and mix evenly, then add 0.5 - 2.0 g of sodium alginate and mix evenly. After ultrasonic treatment to remove bubbles, a mixed solution is obtained; Cross-linking reaction step (S4): Spray the mixed solution into a barium chloride solution with a mass concentration of 1 - 10% for cross-linking reaction. After sufficient reaction, wash with deionized water to obtain a tungsten-doped tin sulfide composite adsorbent.

2. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 1, wherein In the synthesis reaction step (S1), the time of the synthesis reaction is 12 - 72 h, and the temperature of the synthesis reaction is 170 - 240 °C.

3. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 2, wherein, In the synthesis reaction step (S1), the temperature of the synthesis reaction is 200 °C.

4. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 3, characterized in that, In the synthesis reaction step (S1), the molar ratio of anhydrous potassium chloride, tungsten powder, tin powder, and sulfur powder is 12:1.5:6:

18.

5. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 4, wherein, In the synthesis reaction step (S1), the addition amount of deionized water is 1.5 mL.

6. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 5, characterized in that, In the washing step (S2), the time of the cross-linking reaction is 36 - 60 h.

7. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 6, wherein, In the magnetic property endowment step (S3), the molar ratio of tungsten-doped tin sulfide and iron tetroxide is 10:

1.

8. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 7, wherein In the magnetic property endowment step (S3), the addition amount of sodium alginate is 1.0 g.

9. The preparation method of the tungsten-doped tin sulfide composite adsorbent according to claim 8, characterized in that, In the cross-linking reaction step (S4), the mass concentration of the barium chloride solution is 5%.

10. Rubidium adsorption material, which is used to adsorb rubidium ions from rubidium-containing brine, is characterized in that The rubidium adsorption material uses the tungsten-doped tin sulfide composite adsorbent according to any one of claims 1 to 9.

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