A pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, and its preparation method and application

Abstract

The invention discloses a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine and its preparation method and application, and the preparation includes the following steps: S1, preparation of silicon aluminum phosphate aluminum complex: adding silicon source, aluminum source, phosphorus source, composite structure directing agent and deionized water to a reaction device, regulating the pH of the solution to 4-8, stirring, crystallization reaction, filtering and washing after the reaction is completed to obtain a silicon aluminum phosphate aluminum complex; S2, immobilization of molybdenum source: mixing the silicon aluminum phosphate aluminum complex obtained in step S1 with the molybdenum source uniformly, and then roasting, ammonium conversion and granulation treatment are carried out in sequence to obtain a pyrophosphomolybdate adsorbent material. The pyrophosphomolybdate adsorbent material prepared by the present invention is suitable for extracting rubidium and cesium from salt lake brine, and has the advantages of low dissolution loss, large adsorption capacity, high adsorption rate, convenient elution, and reusability.

Description

Technical Field

[0001] The invention belongs to the technical field of adsorption material preparation, and specifically relates to a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, and a preparation method and application thereof. Background Art

[0002] Rubidium and cesium are important rare metal elements. They have similar physical and chemical properties, including strong softness, high ductility, and excellent electrical and thermal conductivity. They can be used interchangeably in many applications. Rubidium and cesium as single substances and their compounds have been widely used in aerospace, energy and chemical, electronics and medicine, and other fields.

[0003] Rubidium and cesium resources are mainly distributed in various solid minerals and salt lake brines. The reserves of solid minerals are limited, and the extraction process is environmentally friendly, which limits the supply of rubidium and cesium. Salt lake brines contain abundant rubidium and cesium resources and have not been developed on a large scale. Therefore, the separation of rubidium and cesium ions in salt lake brines has more application prospects. However, the concentration of rubidium and cesium ions in most salt lake brines is low (~10ppm) and coexists with high concentrations of competing ions (sodium, potassium, magnesium, calcium, etc.), which makes the large-scale exploitation of rubidium and cesium resources in salt lakes face huge challenges. At present, the efficient separation technology for rubidium and cesium resources in salt lake brines mainly consists of precipitation, extraction and adsorption. Among them, the adsorption method has the advantages of high selectivity, low production cost and environmental friendliness, and has great potential for large-scale industrial application of extracting rubidium and cesium resources from salt lake brines.

[0004] In the prior art, there are some reports on the extraction of rubidium and cesium from salt lake brine. For example, Chinese patent document CN117945456A discloses an ammonium thiostannate salt and its preparation method and application. The patent mixes a sulfur source, a tin source, a soluble metal salt and water for hydrothermal reaction to obtain a thiostannate salt; the obtained thiostannate salt is mixed with an ammonium salt to obtain ammonium thiostannate. The ammonium thiostannate salt has high selectivity for cesium, high adsorption capacity, fast kinetics and good cyclic stability in sodium, potassium, rubidium, magnesium, calcium and other ions, and is highly efficient in adsorbing cesium ions in salt lake brine. Another example is the Chinese patent document CN115703060A, which discloses a method for preparing a magnetic bimetallic MOF rubidium and cesium adsorbent, combining the magnetic properties of Fe3O4, the high specific surface area, developed pore structure, adjustable pore size and high adsorption capacity of porous material MOFs, to synthesize a composite adsorbent Fe3O4@CMC@FeMn MOF with a core-shell structure that not only has a high adsorption capacity but is also easy to separate and recycle. However, most of these adsorbent materials are in powder form, and most of them are in a fine powder state, with poor mechanical and hydraulic properties, and cannot be operated in a columnar manner, which limits their practical application range.

[0005] For another example, Chinese patent document CN118719018A discloses a rubidium-cesium adsorbent and its preparation method and application, the rubidium-cesium adsorbent includes a carrier and a heteropolyacid salt and / or heteropolyacid radical connected to the carrier, by using an amino resin or a macroporous white ball as a carrier, and by loading heteropolyacid and ammonium salt on the carrier to obtain the rubidium-cesium adsorbent. The rubidium-cesium adsorbent obtained by the above patent has good mechanical properties, large adsorption capacity, high selectivity, high stability, and can be used to extract rubidium-cesium in liquid mixtures. However, these rubidium-cesium adsorbent materials also have the problems of weak carrier-adsorbent interaction, high dissolution loss, small specific surface area, poor pore uniformity, and poor mechanical strength of materials, which is not conducive to the stable and efficient treatment of rubidium-cesium resources in salt lake brine by adsorbents.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, and a preparation method and application thereof. The pyrophosphomolybdate adsorption material has the advantages of low dissolution loss, large adsorption capacity, high adsorption rate, convenient elution, and reusability, and is suitable for the adsorption and extraction of rubidium and cesium from salt lake brine.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine. The pyrophosphomolybdate adsorption material is obtained by mixing a silicoalumino-aluminophosphate composite molecular sieve with a molybdenum source, followed by roasting and ammonium conversion.

[0010] In the above technical scheme, the silicon-aluminum molecular sieve embedded with ammonium pyrophosphomolybdate can improve the stability of the cross-linked ammonium molybdate. At the same time, the pore structure in the molecular sieve can provide a diffusion channel for the adsorption of rubidium and cesium ions. Combined with the efficient adsorption performance of ammonium pyrophosphomolybdate, the adsorption capacity of the adsorption material for rubidium and cesium ions is improved.

[0011] In the above technical solution, the preparation of the pyrophosphomolybdate adsorption material specifically includes the following steps:

[0012] S1. Preparation of silicon-aluminum-aluminum phosphate composite: adding silicon source, aluminum source, phosphorus source, composite structure directing agent and deionized water into a reaction device, adjusting the pH of the solution to 4-8, stirring, crystallizing reaction, filtering and washing after the reaction is completed to obtain silicon-aluminum-phosphate composite;

[0013] S2. Immobilization of molybdenum source: The silicon aluminum-aluminum phosphate composite obtained in step S1 is uniformly mixed with the molybdenum source, and then calcined, ammonium converted and granulated in sequence to obtain the pyrophosphomolybdate adsorption material.

[0014] As a preferred embodiment of the technical solution of the present invention, in step S1, the silicon source is selected from one or more of tetraethyl orthosilicate, silica sol, and sodium silicate;

[0015] The aluminum source is selected from one or more of aluminum isopropoxide, aluminum sulfate, and pseudo-boehmite;

[0016] The phosphorus source is selected from one or more of phosphoric acid, dipropylammonium phosphate, and diammonium dihydrogen phosphate;

[0017] The composite structure directing agent is selected from one or more of tetraethylammonium hydroxide, N,N-diisopropylethylamine, triethylamine and polyvinylpyrrolidone.

[0018] As a preferred embodiment of the technical solution of the present invention, in step S1, the mass ratio of silicon source, aluminum source, phosphorus source, composite structure directing agent and deionized water is 1: 0.5-2.5: 0.5-5: 0.05-0.4: 100-2000. It is understood that the amount ratio of the above raw materials can be optimized and adjusted within the above range by those skilled in the art.

[0019] As a preferred embodiment of the technical solution of the present invention, in step S1, the crystallization reaction temperature is 180-220°C, and the reaction time is 0.5-5 days. Exemplarily, the crystallization reaction temperature can be 180°C, 181°C, 182°C, 183°C, 184°C, 185°C, 186°C, 187°C, 188°C, 189°C, 190°C, 191°C, 192°C, 193°C, 194°C, 195°C, 196°C, 197°C, 198°C, 199°C, 200°C, 201°C, 202°C, 203°C, 204°C, 205°C, 206°C, 207°C, 208°C, 209°C, 210°C, 211°C, 212°C, 213°C, 214°C, 215°C, 216°C, 217°C, 218°C, 219°C, 220°C, 221°C, 222°C, 223°C, 224°C, 225°C, 226°C, 227°C, 228°C, 229°C, 230°C, 231°C, 232°C, 233°C, 234°C, 235°C, 236°C, 237°C, 238°C, 239°C, 240°C, 241°C, 242°C, 243°C, The reaction time may be a value among 0.5d, 1d, 1.5d, 2d, 2.5d, 3d, 3.5d, 4d, 4.5d, 5d or any value within 0.5-5d, which can be flexibly adjusted by those skilled in the art.

[0020] As a preferred embodiment of the technical solution of the present invention, in step S2, the molybdenum source is selected from one or both of ammonium molybdate and sodium molybdate;

[0021] The mass ratio of the silicoaluminum-aluminum phosphate composite to the molybdenum source is 1:0.1-0.5. It is understood that the amount ratio of the above raw materials can be optimized and adjusted within the above range by those skilled in the art.

[0022] As a preferred embodiment of the technical solution of the present invention, in step S2, the roasting temperature is 450-800°C, and the roasting time is 2-12 hours. Exemplarily, the roasting temperature can be 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 790°C, 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C The calcination time can be a certain value among 0℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃ or any value within the above range; the calcination time can be a certain value among 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h or any value within 2-12h, which can be flexibly adjusted by those skilled in the art.

[0023] As a preferred embodiment of the technical solution of the present invention, in step S2, the treatment step of ammonium conversion is: adding the calcined sample, ammonium source and deionized water into a reaction device in a mass ratio of 1:0.8-1.2:5-20, stirring at 30-80°C for 6-24h, and then filtering, washing and drying;

[0024] The ammonium source is selected from one or both of ammonium sulfate and ammonium acetate.

[0025] In a second aspect, the present invention aims to protect the pyrophosphomolybdate adsorption material prepared by the above scheme.

[0026] In a third aspect, the present invention hopes to provide the use of the above-obtained pyrophosphomolybdate adsorbent material in extracting rubidium and cesium from salt lake brine. Of course, the above-mentioned adsorbent material can also be used in the adsorption treatment of lepidolite leachate containing rubidium and / or cesium.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The pyrophosphate molybdate adsorption material provided by the present invention utilizes a molecular sieve to immobilize the pyrophosphate molybdenum adsorption material. The easy granulation property of the molecular sieve can be used to convert the traditional powdered adsorption material into a granular form, thereby solving the problem that the traditional rubidium-cesium adsorption material has poor mechanical properties, is difficult to shape, and is not suitable for use in a filling column.

[0029] (2) The pyrophosphate molybdate adsorption material provided by the present invention utilizes the periodic porous characteristics of the molecular sieve to provide a convenient mass transfer channel for the diffusion of rubidium and cesium ions in the adsorption material, thereby avoiding the defects of mass transfer difficulties caused by traditional packaging stabilization materials and maintaining the strong adsorption effect of pyrophosphate molybdenum on rubidium and cesium ions.

[0030] (3) The pyrophosphate molybdate adsorption material provided by the present invention is prepared by preparing a composite molecular sieve of silicon aluminum and aluminum phosphate, utilizing the bonding effect between the molecular sieves, and combining the in-situ conversion of the aluminum phosphate molecular sieve into a pyrophosphate molybdate adsorbent, which can enhance the bonding strength and strong synergistic effect between the silicon aluminum molecular sieve and the pyrophosphate molybdenum salt, and improve the dissolution resistance of the adsorbent.

[0031] (4) The pyrophosphomolybdate adsorption material provided by the present invention utilizes a composite of a silicon-alumina molecular sieve and an aluminum phosphate molecular sieve to exert the physical barrier effect between the molecular sieves, realize the preparation of a small-grain pyrophosphomolybdate adsorbent, increase the number of adsorption sites in the molecular sieve, and improve the adsorption capacity of the adsorbent.

[0032] (5) The preparation method of the pyrophosphomolybdate adsorption material provided by the present invention is to obtain pyrophosphomolybdate by utilizing the reaction between aluminum phosphate and molybdate and the dehydration effect of phosphoric acid at high temperature during the process of removing the template from the molecular sieve. Compared with the traditional ammonium phosphomolybdate, pyrophosphomolybdate has a better rubidium-cesium adsorption selectivity.

[0033] In conclusion, the pyrophosphomolybdate adsorption material provided by the present invention is suitable for extracting rubidium and cesium from salt lake brine, and has the advantages of low dissolution loss, large adsorption capacity, high adsorption rate, convenient elution, and reusability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the adsorption cycle test result of Experimental Example 3;

[0035] Figure 2 This is a scanning electron microscope image of the sample of Example 1. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Unless otherwise specified, the chemical reagents used in the present invention are purchased from the market.

[0038] Example 1

[0039] A method for preparing a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, comprising the following steps:

[0040] S1. Preparation of silicon aluminum-aluminum phosphate composite: 6 g of tetraethyl orthosilicate, 10 g of aluminum isopropoxide, 8 g of phosphoric acid, 0.6 g of triethylamine, 0.6 g of polyvinyl pyrrolidone and 2400 g of deionized water were weighed and added into a reaction kettle, stirred at 25° C. for 1 h, the pH of the solution was adjusted to 7 with ammonia water, stirred for 2 h, heated to 200° C., crystallized for 2 d, filtered and washed to obtain a silicon aluminum-aluminum phosphate composite;

[0041] S2. Immobilization of molybdenum source: Mix 10g of silicon aluminum-aluminum phosphate complex with 2g of sodium molybdate, mix evenly by ball milling, transfer to a tubular furnace, set the temperature to 600°C, and roast for 7h. After cooling, add 10g of ammonium sulfate and 100mL of deionized water, add to the reactor, stir at 50°C for 12h, filter, wash, and dry at 70°C to obtain a silicon aluminum molecular sieve immobilized pyrophosphate adsorption material.

[0042] Example 2

[0043] A method for preparing a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, comprising the following steps:

[0044] S1. Preparation of silicon aluminum-aluminum phosphate composite: 3 g of tetraethyl orthosilicate, 3 g of silica sol, 13 g of aluminum sulfate, 25 g of phosphoric acid, 1.0 g of tetraethylammonium hydroxide, 0.8 g of polyvinyl pyrrolidone, 0.2 g of triethylamine and 4000 g of deionized water were weighed and added into a reaction kettle, stirred at 30° C. for 1.5 h, the pH of the solution was adjusted to 6 with ammonia water, stirred for 2 h, heated to 195° C., crystallized for 4 d, filtered and washed to obtain a silicon aluminum-aluminum phosphate composite;

[0045] S2. Immobilization of molybdenum source: Mix 10g of silicon aluminum-aluminum phosphate complex with 4g of ammonium molybdate, mix evenly by ball milling, transfer to a tubular furnace, set the temperature to 700°C, and roast for 8h. After cooling, add 8g of ammonium sulfate and 60mL of deionized water, add to the reactor, stir at 60°C for 15h, filter, wash, and dry at 70°C to obtain a silicon aluminum molecular sieve immobilized pyrophosphate adsorption material.

[0046] Example 3

[0047] A method for preparing a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, comprising the following steps:

[0048] S1. Preparation of silicon aluminum-aluminum phosphate composite: 6 g of tetraethyl orthosilicate, 10 g of aluminum isopropoxide, 8.5 g of aluminum sulfate, 0.6 g of triethylamine, 0.6 g of polyvinyl pyrrolidone and 2000 g of deionized water were weighed and added into a reaction kettle, stirred at 25° C. for 1.5 h, the pH of the solution was adjusted to 6.5 with ammonia water, stirred for 2 h, heated to 190° C., crystallized for 2 d, filtered and washed to obtain a silicon aluminum-aluminum phosphate composite;

[0049] S2. Immobilization of molybdenum source: Mix 10g of silicon aluminum-aluminum phosphate complex with 2g of sodium molybdate, mix evenly by ball milling, transfer to a tube furnace, set the temperature to 620°C, roast for 6.5h, add 12g of ammonium acetate and 80mL of deionized water after cooling, add to the reactor, stir at 45°C for 16h, filter, wash, and dry at 70°C to obtain silicon aluminum molecular sieve immobilized pyrophosphate adsorption material.

[0050] Example 4

[0051] A method for preparing a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, comprising the following steps:

[0052] S1. Preparation of silicon aluminum-aluminum phosphate composite: weigh 6 g of sodium silicate, 10 g of aluminum isopropoxide, 7.5 g of phosphoric acid, 0.55 g of triethylamine, 0.5 g of polyvinyl pyrrolidone and 2000 g of deionized water, add them into a reactor, stir at 30° C. for 1 h, adjust the pH of the solution to 6 with ammonia water, stir for 2 h, heat to 210° C., crystallize for 1.5 d, filter, wash, and obtain silicon aluminum-aluminum phosphate composite;

[0053] S2. Immobilization of molybdenum source: Mix 10g of silicon aluminum-aluminum phosphate complex with 1.8g of sodium molybdate, mix evenly by ball milling, transfer to a tubular furnace, set the temperature to 620°C, roast for 6.5h, add 8g of ammonium sulfate and 100mL of deionized water after cooling, add to the reactor, stir at 45°C for 16h, filter, wash, and dry at 75°C to obtain a silicon aluminum molecular sieve immobilized pyrophosphate adsorption material.

[0054] Example 5

[0055] A method for preparing a pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine, comprising the following steps:

[0056] S1. Preparation of silicon aluminum-aluminum phosphate composite: 5.5 g of tetraethyl orthosilicate, 10 g of aluminum isopropoxide, 8 g of phosphoric acid, 0.6 g of triethylamine, 0.65 g of polyvinyl pyrrolidone and 2400 g of deionized water were weighed and added into a reaction kettle, stirred at 30° C. for 1 h, the pH of the solution was adjusted to 7.2 with ammonia water, stirred for 2 h, heated to 205° C., crystallized for 1.5 d, filtered and washed to obtain a silicon aluminum-aluminum phosphate composite;

[0057] S2. Immobilization of molybdenum source: Mix 10g of silicon aluminum-aluminum phosphate complex with 2.2g of sodium molybdate, mix evenly by ball milling, transfer to a tubular furnace, set the temperature to 610°C, roast for 8h, add 9g of ammonium sulfate and 100mL of deionized water after cooling, add to the reactor, stir at 50°C for 16h, filter, wash, and dry at 75°C to obtain a silicon aluminum molecular sieve immobilized pyrophosphate adsorption material.

[0058] Comparative Example 1

[0059] A method for preparing a pyrophosphomolybdate adsorption material comprises the following steps:

[0060] (1) 10 g of aluminum isopropoxide, 8 g of phosphoric acid, 0.6 g of triethylamine, 0.6 g of polyvinyl pyrrolidone and 2400 g of deionized water were weighed and added into a reaction kettle, stirred at 25° C. for 1 h, the pH of the solution was adjusted to 7 with aqueous ammonia, stirred for 2 h, heated to 200° C., crystallized for 2 d, filtered, and washed to obtain an aluminum phosphate complex;

[0061] (2) 10 g of aluminum phosphate complex was mixed with 2 g of sodium molybdate, mixed evenly by ball milling, transferred to a tube furnace, set the temperature to 600 ° C, roasted for 7 h, and after cooling, 10 g of ammonium sulfate and 100 mL of deionized water were added to the reactor, stirred at 50 ° C for 12 h, filtered, washed, and dried at 70 ° C to obtain a pyrophosphate adsorption material.

[0062] Test Example 1

[0063] The adsorption materials prepared in Examples 1 to 5 and Comparative Example 1 were subjected to a rubidium-cesium adsorption experiment. The specific method is as follows: a glass filling column with a diameter of 2.5 cm and a height of 30 cm was taken, 50 g of rubidium-cesium adsorption material was loaded, and after compaction, simulated salt lake brine containing rubidium and cesium (the concentration of each element is shown in Table 1) was pumped into the column at a flow rate of 8 BV / h. The liquid was fully in contact with the adsorbent when flowing through the adsorption filler bed, and selective adsorption was achieved through ion exchange. The effluent after continuous adsorption for 4 hours was collected, and Rb in the effluent was detected by ICP-MS. + and Cs + The test results are shown in Table 2.

[0064] Table 1 Composition of simulated salt lake brine

[0065] cation <![CDATA[Rb + ]]> <![CDATA[Cs + ]]> <![CDATA[Li + ]]> <![CDATA[Ca 2+ ]]> <![CDATA[K + ]]> <![CDATA[Na + ]]> <![CDATA[Mg 2+ ]]> Concentration / ppm 20 20 100 500 45000 80000 12000

[0066] Table 2 Material adsorption test results

[0067]

[0068]

[0069] Test Example 2

[0070] 50g of the rubidium-cesium adsorption materials prepared in Examples 1 to 5 and Comparative Example 1 were respectively added to 50L of an aqueous solution containing 200ppm of rubidium or cesium to adsorb rubidium and cesium. After saturation, the rubidium-cesium adsorption materials were filtered out, and the residual ion content in the simulated salt lake brine was detected by ICP-MS to calculate the saturated adsorption capacity of the adsorption materials. The test results are shown in Table 3.

[0071] Table 3 Material adsorption test results

[0072]

[0073] It can be seen from the data in Table 2 and Table 3 that the silica-alumina molecular sieve-supported pyrophosphate adsorption material prepared in the present invention has a large specific surface area, high strength, high adsorption capacity for rubidium and cesium, and fast adsorption rate.

[0074] Test Example 3

[0075] In order to further test the regeneration performance of the silica-alumina molecular sieve immobilized pyrophosphate adsorption material prepared by the present invention, the present invention regenerates the material after saturated adsorption in Example 1 in Experimental Example 2, and the method is as follows: add the saturated pyrophosphomolybdate adsorption material for rubidium and cesium extraction to the ammonium salt solution and soak for at least 30 minutes, then wash the adsorption material with pure water to neutrality, repeat 2 times, and then use it for the next adsorption cycle of Experimental Example 2. The ammonium salt solution is ammonium chloride with a concentration of 1 mol / L, and the solid-liquid ratio of the saturated pyrophosphomolybdate adsorption material for extracting rubidium and cesium from salt lake brine to the ammonium salt solution is 1:8, and the unit is g:mL.

[0076] from Figure 1 It can be seen that the silica-alumina molecular sieve-supported pyrophosphate adsorption material prepared in the present invention has high adsorption stability and good dissolution resistance.

[0077] The present invention illustrates the technical concept of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of individual raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine, characterized in that: The pyrophosphomolybdate adsorption material is obtained by mixing a silicon aluminum-aluminum phosphate composite molecular sieve with a molybdenum source, and then calcining and converting it into ammonium.

2. The method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine according to claim 1, characterized in that: The steps include: S1. Preparation of silicon-aluminum-aluminum phosphate composite: adding silicon source, aluminum source, phosphorus source, composite structure directing agent and deionized water into a reaction device, adjusting the pH of the solution to 4-8, stirring, crystallizing reaction, filtering and washing after the reaction is completed to obtain silicon-aluminum-phosphate composite; S2. Immobilization of molybdenum source: The silicon aluminum-aluminum phosphate composite obtained in step S1 is uniformly mixed with the molybdenum source, and then calcined, ammonium converted and granulated in sequence to obtain the pyrophosphomolybdate adsorption material.

3. The method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine according to claim 2, characterized in that: In step S1, the silicon source is selected from one or more of tetraethyl orthosilicate, silica sol, and sodium silicate; The aluminum source is selected from one or more of aluminum isopropoxide, aluminum sulfate, and pseudo-boehmite; The phosphorus source is selected from one or more of phosphoric acid, dipropylammonium phosphate, and diammonium dihydrogen phosphate; The composite structure directing agent is selected from one or more of tetraethylammonium hydroxide, N,N-diisopropylethylamine, triethylamine and polyvinylpyrrolidone.

4. The method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine according to claim 2, characterized in that: In step S1, the mass ratio of the silicon source, the aluminum source, the phosphorus source, the composite structure directing agent and the deionized water is 1:0.5~2.5:0.5~5:0.05~0.4:100~2000.

5. The method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine according to claim 2, characterized in that: In step S1, the crystallization reaction temperature is 180-220° C., and the reaction time is 0.5-5 d.

6. The method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine according to claim 2, characterized in that: In step S2, the molybdenum source is selected from one or both of ammonium molybdate and sodium molybdate; The mass ratio of the silicon aluminum-aluminum phosphate complex to the molybdenum source is 1:0.1~0.

5.

7. The method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine according to claim 2, characterized in that: In step S2, the calcination temperature is 450-800°C, and the calcination time is 2-12 hours.

8. The method for preparing a pyrophosphomolybdate adsorbent material for extracting rubidium and cesium from salt lake brine according to claim 2, characterized in that: In step S2, the treatment step of ammonium conversion is: adding the calcined sample, ammonium source and deionized water into a reaction device in a mass ratio of 1:0.8-1.2:5-20, stirring at 30-80°C for 6-24h, and then filtering, washing and drying; The ammonium source is selected from one or both of ammonium sulfate and ammonium acetate.

9. The pyrophosphomolybdate adsorption material prepared by the method according to any one of claims 1 to 8.

10. Use of the pyrophosphomolybdate adsorbent material according to claim 9 in extracting rubidium and cesium from salt lake brine.

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