A strontium ion adsorption material for high-salinity wastewater and a preparation method and application thereof

Abstract

This invention discloses a strontium ion adsorption material for high-salinity wastewater, its preparation method, and its application, belonging to the field of solid waste resource utilization. The preparation method involves mixing phosphate, fluoride, and polyethylene glycol, grinding and mixing them uniformly, adding titanium tetrachloride, grinding and mixing uniformly, carrying out a solid-phase reaction, and then washing and drying. This invention utilizes a Ti-O-P inorganic framework and F... ‑ Local structural regulation and polyethylene glycol pore structure modulation were used to construct Sr with a hierarchical pore structure. 2+ Adsorption materials, in high-salt systems and Na + Ca 2+ Under conditions of coexistence of competing ions, the adsorbent material of the present invention still exhibits good Sr... 2+ The method of this invention has excellent adsorption performance, salt tolerance, and chemical stability. Compared with traditional processes, the preparation method adopts a solid-phase synthesis method, which avoids complex liquid-phase precursor processes. It has the advantages of simple preparation process and low environmental impact, and is suitable for salt lake brine, high-salt industrial wastewater, and complex water containing strontium.

Description

Technical Field

[0001] This invention belongs to the field of solid waste recycling, specifically relating to a strontium ion adsorption material for high-salt wastewater, its preparation method, and its application. Background Technology

[0002] High-salinity brines, salt lake brines, and industrial salt mud contain abundant strontium resources. However, the high salinity, high hardness, and complex ion coexistence characteristics of these systems pose significant challenges to the efficient separation of strontium ions. Traditional strontium extraction methods mainly include chemical precipitation, solvent extraction, membrane separation, ion exchange, and adsorption separation. Chemical precipitation offers advantages such as simple equipment and mature technology, but it is prone to co-precipitation in high-salinity environments, requiring large amounts of chemical reagents and generating significant amounts of by-product salts and sludge, increasing processing pressure. Solvent extraction achieves high selectivity but typically requires organic extractants and large amounts of auxiliary reagents, resulting in high costs and secondary wastewater generation. Membrane separation technology offers high separation efficiency, but membrane fouling, equipment investment, and operating and maintenance costs limit its large-scale application. Ion exchange and adsorption separation have gained widespread attention due to their ease of operation, low energy consumption, and suitability for complex water systems. The organic resins used in ion exchange have good exchange performance, but they are prone to decreased exchange capacity, performance degradation, and increased regeneration wastewater under high-salinity and high-hardness environments. Inorganic adsorbent materials used in adsorption separation methods possess advantages such as structural stability, corrosion resistance, radiation resistance, and tunable crystal structures, making them an important research direction for strontium separation in high-salt systems. Currently reported inorganic materials such as titanates and phosphates can adsorb strontium ions (Sr) through ion exchange, surface complexation, and lattice intercalation. 2+ However, there are still problems such as the development of more low-salt or single-ion systems, insufficient selectivity for complex salt systems, complex preparation processes, and limited utilization of effective active sites.

[0003] Chinese patent CN103752259B discloses a silica-based titanate composite adsorbent for removing radioactive strontium and its preparation method. This patent uses porous silica as a carrier, loading titanate into the microporous structure of silica via a sol-gel method to form a silica-based titanate composite adsorbent material. While this method relies on the silica carrier to load titanate into a composite structure, which improves the material's mechanical strength, the carrier itself does not directly provide active sites for strontium ion adsorption, thus limiting the proportion of effective adsorbent components. Furthermore, the patent method requires multiple steps, including sol-gel, solvent treatment, and high-temperature sintering, with sintering temperatures reaching up to 1100℃. This high-temperature process not only increases energy consumption but may also lead to changes in the material's pore structure and a reduction in some active sites.

[0004] Chinese patent CN107346670B discloses a method for removing high-salt wastewater. 90 This patented method for Sr precipitation addresses the limitations of traditional precipitation methods in high-salt environments by employing a precipitating adsorbent containing tetravalent titanium ions. By adjusting the pH of the wastewater, the titanium ions form a precipitated adsorbent phase, thereby removing radioactive strontium from high-salt wastewater. Essentially, this method remains an in-situ precipitation adsorption technology, where the adsorbent material is dynamically formed during the treatment process. The crystal structure, pore structure, and surface active sites of the material are difficult to precisely control. Therefore, while this method can remove strontium in high-salt environments, there is still room for improvement in adsorption capacity, selective adsorption performance, and material structural stability. Furthermore, the precipitation process relies on pH adjustment and solid-liquid separation, which is not conducive to constructing functionalized adsorbent materials with well-defined structural characteristics and long-term stability.

[0005] In summary, current titanium-based inorganic adsorbent materials are mostly prepared using sol-gel, hydrothermal synthesis, and carrier loading methods. These methods typically require a liquid-phase precursor system and involve complex crystal growth control processes, resulting in long process flows, demanding equipment requirements, and difficulties in large-scale preparation. Existing solid-phase or high-temperature synthesized inorganic adsorbent materials usually require high-temperature treatment to promote crystal formation, but high-temperature processes may lead to pore structure collapse, a reduction in active sites, and increased energy consumption. Meanwhile, some materials rely on carrier loading, complex templates, or multi-step modification processes to achieve performance improvements, which involve complex preparation processes and increased costs. Therefore, it is crucial to develop a method with a simple preparation process, stable structure, abundant strontium adsorption active sites, and the ability to adsorb strontium onto Na+. + Ca 2+ Mg 2+ Strontium ion adsorption materials that maintain high selectivity under conditions of coexistence of high-concentration competing ions are of great significance for the resource utilization of high-salinity wastewater. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention proposes a strontium ion adsorption material for high-salinity wastewater, its preparation method, and its application. The preparation process of the strontium ion adsorption material for high-salinity wastewater is simple, the structure is stable, it has abundant strontium adsorption active sites, and it can adsorb strontium ions into Na+. + Ca 2+ Mg 2+ Even under conditions of high concentrations of competing ions coexisting, it can still target Sr. 2+ Highly selective adsorption is achieved.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for preparing a strontium ion adsorption material for high-salinity wastewater includes the following steps: Step S01: Mix phosphate, fluoride, and polyethylene glycol, grind and mix evenly, add titanium tetrachloride, grind and mix evenly to obtain a mixed abrasive; Step S02: Place the mixed grinding material in a sealed reaction container for solid-phase reaction. After the reaction is completed, wash and dry to obtain strontium ion adsorption material for high-salt wastewater.

[0008] Preferably, in step S01, the phosphate is one or a combination of ammonium hydrate phosphate and ammonium dihydrogen phosphate; The fluoride salt is one or a combination of ammonium fluoride and ammonium bifluoride; The polyethylene glycol is polyethylene glycol 2000-6000.

[0009] More preferably, in step S01, the phosphate is hydrated ammonium phosphate; The fluoride salt is ammonium fluoride; The polyethylene glycol is polyethylene glycol 4000.

[0010] Preferably, in step S01, the molar ratio of titanium tetrachloride, phosphate, and fluoride is 1:3-6:0.1-0.4; The mass of polyethylene glycol is 5-8% of the mass of titanium tetrachloride.

[0011] Preferably, in step S01, titanium tetrachloride is added dropwise while stirring.

[0012] More preferably, in step S01, titanium tetrachloride is added by stirring and dripping, with a dripping time of 2-10 minutes.

[0013] Preferably, in step S01, the grinding method used to grind and mix the materials evenly is manual grinding.

[0014] Furthermore, in step S01, the standard for uniform grinding and mixing is grinding until the mixture is in the form of a paste.

[0015] Preferably, in step S02, the reaction temperature of the solid-phase reaction is 120-150℃, and the reaction time is 12-24h.

[0016] Preferably, in step S02, the washing solution used during washing is deionized water and ethanol, and the washing conditions are to wash with deionized water 1-2 times, and then wash with ethanol 1-2 times.

[0017] More preferably, in step S02, the washing solution used during washing is deionized water and ethanol. The washing conditions are to wash with deionized water 1-2 times, then wash with ethanol 1-2 times, and to separate the precipitate by centrifugation after each washing. The centrifugation rate is 8000-10000 r / min, and the centrifugation time is 2-4 min.

[0018] Preferably, in step S02, the drying temperature is 60-80℃ and the drying time is 4-6h.

[0019] A strontium ion adsorption material for high-salt wastewater prepared by the aforementioned preparation method.

[0020] An application of a high-salt wastewater strontium ion adsorption material prepared by the aforementioned preparation method includes the following steps: adding the high-salt wastewater strontium ion adsorption material to a high-salt strontium-containing solution for adsorption; after adsorption is completed, solid-liquid separation is performed to obtain the material after adsorbing strontium ions and the treated solution.

[0021] Preferably, the high-salt strontium-containing solution contains Sr. 2+ and competing ions, said competing ions including Na + Ca 2+ Mg 2+ One or a combination thereof; The amount of strontium ion adsorption material added to the high-salt wastewater strontium-containing solution is 0.5-2 g / L.

[0022] Compared with the prior art, the beneficial effects of this invention are as follows: (1) This invention addresses the existing high-salt system, specifically in the case of Sr 2+ To address the issue of insufficient selectivity during the separation process, a method based on a Ti-OP inorganic framework and F is proposed. - Strontium ion adsorption materials for high-salinity wastewater, characterized by structural regulation and synergistic regulation using polyethylene glycol templates. Existing titanium-based and phosphate-based inorganic adsorption materials can achieve Strontium ion adsorption through ion exchange, surface complexation, and lattice embedding. 2+ Adsorption is possible, but most materials are designed for low-salt or single-ion systems, and in Na+... + Ca 2+ Mg 2+ Under conditions of high concentrations of competing ions coexisting, competitive adsorption easily occurs, leading to Sr 2+ The adsorption capacity and selectivity are significantly reduced. Furthermore, traditional liquid-phase synthesis methods typically require complex precursor solution preparation, solvent assistance, and crystal growth control processes, resulting in complex processes, high energy consumption, and difficulties in large-scale preparation. This invention constructs a four-component synergistic system using titanium tetrachloride, phosphate, fluoride, and polyethylene glycol, and prepares the adsorbent material using solid-phase heat treatment. This avoids complex liquid-phase precursor processes while achieving synergistic optimization of material structure and adsorption performance.

[0023] (2) The components in this invention are not simply physically combined, but play a synergistic regulatory role in the solid-state reaction process. Among them, titanium tetrachloride, as the titanium source, undergoes a solid-state reaction with phosphate during heat treatment to form a stable inorganic framework structure connected by Ti-OP bonds, providing a stable crystal structure and Sr for the material. 2+ Binding sites; phosphate groups provide abundant oxygen coordination environments, enhancing Sr binding through ion exchange and surface complexation. 2+ Complexing ability; F in fluoride salts - It can regulate the local coordination environment of Ti centers, promote crystal structure adjustment and defect construction, and increase the number of active sites on the material surface; as a structure regulator, polyethylene glycol can regulate the contact mode between particles during solid-phase mixing and heat treatment, inhibit excessive particle aggregation, promote the formation of hierarchical porous structure, and increase the exposure of internal active sites.

[0024] (3) This invention uses a solid-phase synthesis method to prepare adsorbent materials. Compared with traditional liquid-phase preparation methods such as sol-gel, hydrothermal synthesis, and carrier loading, it has advantages such as simple process flow, high raw material utilization, and low environmental impact. During the solid-phase synthesis reaction, the raw material components directly contact and undergo crystal phase recombination, without the need for a large amount of solvent or complex pH adjustment and precursor liquid control processes, which can effectively reduce waste liquid generation and post-treatment steps. At the same time, solid-phase heat treatment is conducive to the formation of a stable Ti-OP inorganic framework structure, and through F - Adjusting the local crystal environment improves the structural stability of the material.

[0025] (4) The adsorbent material obtained by the present invention has excellent Sr 2+ Performance: The adsorption capacity reached 375.4 mg / g. Compared with adsorption materials without optimized structural control conditions (polyethylene glycol template agent, solid-phase reaction time, and ethanol washing), the adsorption capacity of the material of this invention was increased by 2.71 times, 10.62 times, and 0.38 times, respectively. This demonstrates the effectiveness of Ti-OP framework construction and F... - There is a clear synergistic effect between structural regulation and polyethylene glycol template, and the performance improvement is not simply the result of process parameter optimization.

[0026] (5) The adsorbent material of the present invention still exhibits good Sr performance under high salt competition environment. 2+ Selective adsorption capacity and high Sr 2+ / Ca 2+ 、Sr 2+ / Na + Competitive selectivity. In the study of Na... + =17435ppm, Ca 2+ =9294ppm, Mg 2+ =205ppm, Sr2+ After static adsorption in a high-salt solution with a concentration of 586 ppm and a pH of 5.5, Sr 2+ Concentration decreased by 41.0%, Ca 2+ The concentration decreased by 0.3%, Na + A 0.05% decrease in concentration of Mg 2+ Although there was a certain decrease in concentration, it was far lower than that of Sr. 2+ The adsorption response demonstrates the adsorption effect of the adsorbent material of the present invention on Sr. 2+ It exhibits a clear preferential binding characteristic. Specifically, the phosphate group in the Ti-OP framework provides oxygen coordination sites, and F... - Regulating the local crystal environment formed to improve Sr 2+ Adaptability to enter active sites, and the hierarchical porous structure induced by polyethylene glycol further promotes Sr 2+ Diffusion and site exposure allow the material to diffuse in Na + Ca 2+ It maintains high selectivity even under conditions of coexistence of competing ions. Therefore, the adsorbent material of this invention not only has high Sr 2+ Adsorption capacity, while also exhibiting good resistance to high salt interference and Sr 2+ Selected enrichment capacity, suitable for strontium resource recovery in complex high-salinity wastewater systems.

[0027] (6) The raw materials used in the preparation method of this invention are widely available and relatively inexpensive. The preparation process is simple and has good repeatability, making it suitable for the recovery of strontium resources in complex systems such as high-salinity brine, salt lake brine, produced water from oil and gas fields, and industrial high-salinity wastewater. Compared with traditional chemical precipitation, multi-stage membrane separation, and complex extraction separation processes, this invention utilizes adsorption separation to achieve Sr... 2+ Selective enrichment can reduce the consumption of chemical reagents and the generation of by-products, thereby reducing the pressure on subsequent processing and demonstrating good economic benefits and application prospects. Attached Figure Description

[0028] Figure 1 The nitrogen adsorption-desorption isotherm curve of the adsorption material obtained in Example 1 is shown below. Figure 2 The X-ray diffraction pattern of the adsorbent material obtained in Example 1 is shown below. Figure 3 Here is a scanning electron microscope image of the adsorbent material obtained in Example 1; Figure 4 The image shows the energy spectrum of the adsorbent material obtained in Example 1. Detailed Implementation

[0029] The present invention will now be described in detail with reference to embodiments and accompanying drawings, but the scope of protection of the present invention is not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified by the manufacturer, are all commercially available conventional products.

[0030] An embodiment of the present invention provides a method for preparing a strontium ion adsorption material for high-salinity wastewater, comprising the following steps: Step S01: Mix phosphate, fluoride, and polyethylene glycol, grind and mix evenly, add titanium tetrachloride, grind and mix evenly to obtain a mixed abrasive; Step S02: Place the mixed grinding material in a sealed reaction container for solid-phase reaction. After the reaction is completed, wash and dry to obtain strontium ion adsorption material for high-salt wastewater.

[0031] Preferably, in step S01, the phosphate is one or a combination of ammonium hydrate phosphate and ammonium dihydrogen phosphate.

[0032] Preferably, in step S01, the fluoride salt is one or a combination of ammonium fluoride and ammonium bifluoride.

[0033] Preferably, in step S01, the polyethylene glycol is polyethylene glycol 2000-6000.

[0034] More preferably, in step S01, the phosphate is hydrated ammonium phosphate.

[0035] More preferably, in step S01, the fluoride salt is ammonium fluoride.

[0036] More preferably, in step S01, the polyethylene glycol is polyethylene glycol 4000.

[0037] Preferably, in step S01, the molar ratio of titanium tetrachloride, phosphate, and fluoride is 1:3-6:0.1-0.4.

[0038] Preferably, in step S01, the mass of polyethylene glycol is 5-8% of the mass of titanium tetrachloride.

[0039] Preferably, in step S01, titanium tetrachloride is added dropwise while stirring.

[0040] More preferably, in step S01, titanium tetrachloride is added by stirring and dripping, with a dripping time of 2-10 minutes.

[0041] Preferably, in step S01, the grinding method used to grind and mix the materials evenly is manual grinding.

[0042] Furthermore, in step S01, the standard for uniform grinding and mixing is grinding until the mixture is in the form of a paste.

[0043] Preferably, in step S02, the reaction temperature of the solid-phase reaction is 120-150℃, and the reaction time is 12-24h.

[0044] Preferably, in step S02, the washing solution used during washing is deionized water and ethanol, and the washing conditions are to wash with deionized water 1-2 times, and then wash with ethanol 1-2 times.

[0045] More preferably, in step S02, the washing solution used during washing is deionized water and ethanol. The washing conditions are to wash with deionized water 1-2 times, then wash with ethanol 1-2 times, and to separate the precipitate by centrifugation after each washing. The centrifugation rate is 8000-10000 r / min, and the centrifugation time is 2-4 min.

[0046] Preferably, in step S02, the drying temperature is 60-80℃ and the drying time is 4-6h.

[0047] Embodiments of the present invention also provide a strontium ion adsorption material for high-salt wastewater prepared by the preparation method described above.

[0048] Embodiments of the present invention also provide the application of the high-salt wastewater strontium ion adsorption material prepared by the preparation method, comprising the following steps: adding the high-salt wastewater strontium ion adsorption material to a high-salt strontium-containing solution for adsorption, and performing solid-liquid separation after adsorption to obtain the material adsorbed with strontium ions and the treated solution.

[0049] Preferably, the high-salt strontium-containing solution contains Sr. 2+ and competing ions, said competing ions including Na + Ca 2+ Mg 2+ One or a combination thereof; The amount of strontium ion adsorption material added to the high-salt wastewater strontium-containing solution is 0.5-2 g / L.

[0050] Example 1 (1) Grind 30 mmol ammonium phosphate hydrate, 3 mmol ammonium fluoride and polyethylene glycol 4000 until uniform (grinding is done manually for 5 minutes, and the standard for judging uniform mixing is that the mixture is ground into a paste). Transfer the uniformly ground mixture into an agate mortar and add 10 mmol titanium tetrachloride dropwise while stirring for 3 minutes. After the addition is completed, continue grinding until the mixture is ground into a paste to obtain a mixed grinding material; wherein, the mass of polyethylene glycol 4000 is 6% of the mass of titanium tetrachloride. (2) The mixed grinding material was transferred to a polytetrafluoroethylene reactor and sealed for reaction at a temperature of 140°C for 24 hours. After the reaction, the mixture was washed twice with deionized water and once with ethanol. After each washing, the precipitate was separated by centrifugation at a speed of 8000 rpm for 2 minutes. The mixture was then transferred to an oven at a temperature of 60°C for 6 hours to obtain the strontium ion adsorption material for high-salt wastewater.

[0051] Example 2 (1) Grind 30 mmol ammonium phosphate hydrate, 1 mmol ammonium fluoride and polyethylene glycol 4000 until uniform (grinding is done manually for 5 minutes, and the standard for judging uniform mixing is that the mixture is ground into a paste). Transfer the uniformly ground mixture into an agate mortar and add 10 mmol titanium tetrachloride dropwise while stirring for 3 minutes. After the addition is completed, continue grinding until the mixture is ground into a paste to obtain a mixed grinding material; wherein, the mass of polyethylene glycol 4000 is 5% of the mass of titanium tetrachloride. (2) The mixed grinding material was transferred to a polytetrafluoroethylene reactor and sealed for reaction at a temperature of 120°C for 12 hours. After the reaction, the mixture was washed once with deionized water and then once with ethanol. After each washing, the precipitate was separated by centrifugation at a speed of 8000 rpm for 2 minutes. The mixture was then transferred to an oven at a temperature of 60°C for 4 hours to obtain the strontium ion adsorption material for high-salt wastewater.

[0052] Example 3 (1) Grind 60 mmol ammonium phosphate hydrate, 4 mmol ammonium fluoride and polyethylene glycol 4000 until uniform (grinding is done manually for 5 minutes, and the standard for judging uniform mixing is that the mixture is ground into a paste). Transfer the uniformly ground mixture into an agate mortar, and add 10 mmol titanium tetrachloride dropwise while stirring for 3 minutes. After the addition is completed, continue grinding until the mixture is ground into a paste to obtain a mixed grinding material; wherein, the mass of polyethylene glycol 4000 is 8% of the mass of titanium tetrachloride. (2) The mixed grinding material was transferred to a polytetrafluoroethylene reactor and sealed for reaction at a temperature of 150°C for 24 hours. After the reaction, the mixture was washed twice with deionized water and then twice with ethanol. After each washing, the precipitate was separated by centrifugation at a speed of 10,000 rpm for 2 minutes. The mixture was then transferred to an oven at a temperature of 80°C for 6 hours to obtain the strontium ion adsorption material for high-salt wastewater.

[0053] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that polyethylene glycol 4000 is not added in step (1), while other processes and reaction conditions remain unchanged.

[0054] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the reaction time in step (2) is changed from 24h to 8h, while the other processes and reaction conditions remain unchanged.

[0055] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that ethanol is not used in the washing process in step (2), while other processes and reaction conditions remain unchanged.

[0056] Application Example 1 Take 100 mg of each of the adsorbent materials prepared in Example 1 and Comparative Examples 1-3, and add them to 100 mL of pure strontium solution (pure strontium solution is an aqueous solution of strontium chloride hexahydrate, wherein the concentration of strontium chloride hexahydrate is 2000 mg / L). After static adsorption at room temperature for 10 min, centrifuge and collect the supernatant. Use ICP to test the change in strontium ion concentration before and after static adsorption, and calculate the effect of strontium ion concentration on Sr. 2+ The adsorption capacity is calculated using the following formula: For Sr 2+ The formula for calculating the adsorption capacity is: q = (C 吸附前 -C 吸附后 )*V / m, where C 吸附前 Sr in the solution before adsorption 2+ Concentration, in mg / L; C 吸附后 Sr in the solution after adsorption 2+ Concentration, in mg / L; V, solution volume, in L; m, adsorbent dosage, in g.

[0057] For Sr 2+ The calculated adsorption capacity results are shown in Table 1.

[0058] Application Example 2 100 mg of the adsorbent material prepared in Example 1 was added to 100 mL of a high-salt solution, wherein the concentrations of each ion were as follows: Na + =17435ppm, Ca 2+ =9294ppm, Mg 2+ =205ppm, Sr 2+ =586ppm, pH=5.5. After static adsorption at room temperature for 0.5h, centrifugation was performed, and the supernatant was collected. Na+ was measured using ICP. + Ca 2+ Mg 2+ 、Sr 2+ Changes in ion concentration, adsorption of the adsorbent material prepared in Example 1 in a high-salt solution (i.e., before and after static adsorption, Na+)+ Ca 2+ Mg 2+ 、Sr 2+ The concentrations are shown in Table 2; Then calculate the effect on Na. + Ca 2+ Mg 2+ 、Sr 2+ The adsorption capacity is calculated using the following formula: To Na + Ca 2+ Mg 2+ 、Sr 2+ The formula for calculating adsorption capacity is: q Na或Ca或Mg或Sr =(C 吸附前Na或Ca或Mg或Sr -C 吸附后Na或Ca或Mg或Sr )*V / m, C 吸附前Na或Ca或Mg或Sr To adsorb Na from high-salt solutions before adsorption + Ca 2+ Mg 2+ 、Sr 2+ The concentration, in mg / L; C 吸附后Na或Ca或Mg或Sr For Na in the high-salt solution after adsorption + Ca 2+ Mg 2+ 、Sr 2+ The concentration is expressed in mg / L; V is the volume of the high-salt solution in L; and m is the mass of the adsorbent in g. The adsorption selectivity coefficient is then calculated using the following formula: The formula for calculating the adsorption selectivity coefficient is: K Sr / M =(q Sr / C Sr ) / (q M / C M ), where q Sr and q M Sr 2+ and competing ion M (Na) + or Ca 2+ The adsorption capacity of C Sr and C M These represent the corresponding ion concentrations after adsorption.

[0059] To Na + Ca 2+ 、Sr 2+ The calculated adsorption capacity and adsorption selectivity coefficient are shown in Table 3.

[0060] Table 1. Adsorption materials prepared in Example 1 and Comparative Examples 1-3 for Sr 2+ adsorption capacity

[0061] Table 2 Adsorption of the adsorbent material prepared in Example 1 in high-salt solution

[0062] Table 3. Adsorption of Na+ by the adsorbent material prepared in Example 1 in high-salt solution. + Ca 2+ Mg 2+ 、Sr 2+ Adsorption capacity and adsorption selectivity coefficient

[0063] Considering the cost of using ICP for full elemental analysis, the data in Table 1 were used to determine the adsorption effect of the adsorbent material obtained in Example 1 on Sr. 2+ After the adsorption capacity of the material was much higher than that of the adsorption materials obtained in Comparative Examples 1-3, only the adsorption material obtained in Example 1 was subjected to a high-salt competition system (Na+). + Ca 2+ Mg 2+ Coexistence adsorption experiments were conducted to verify the selective adsorption performance of the adsorbent material obtained in Example 1 in complex systems.

[0064] As shown in Table 1, the adsorption capacity of the adsorbent material obtained in Example 1 is 375.4 mg / g, which is much higher than that of the adsorbent materials obtained in Comparative Examples 1-3 under the same test conditions. This indicates that the use of template agent, control of reaction time, and selection of anhydrous ethanol for cleaning will affect the adsorption effect.

[0065] Comparing the adsorption capacities of the adsorbent material obtained in Example 1 with those obtained in Comparative Example 2 in Table 1, it can be seen that the Sr of the adsorbent material obtained in Example 1 is higher. 2+ The adsorption capacity reached 375.4 mg / g, while the adsorption capacity of the adsorbent material obtained in Comparative Example 1 was only 101.2 mg / g, only 27% of that in Example 1. The performance difference between Example 1 and Comparative Example 1 indicates that, under the same solid-phase reaction conditions, the introduction of polyethylene glycol 4000 has a significant effect on improving the strontium ion adsorption performance of the material. In the system of this invention, polyethylene glycol 4000 not only acts as a template but also plays a role in spatial regulation and structure induction during solid-phase mixing and heat treatment. The polyethylene glycol 4000 molecular chains can regulate the contact state between components, reduce excessive particle agglomeration, and improve the uniformity of the material structure. During heat treatment, polyethylene glycol 4000 helps to form an open pore structure, increasing the specific surface area and pore connectivity of the material, allowing for more Ti-OP structures and F... - The active environment formed by regulation is fully exposed, providing a suitable environment for Sr 2+ Adsorption provides more effective sites.

[0066] Comparing the adsorption capacities of the adsorbent material obtained in Example 1 with those obtained in Comparative Example 2 in Table 1, it can be seen that the Sr of the adsorbent material obtained in Example 1 is higher. 2+ The adsorption capacity reached 375.4 mg / g, while the adsorption capacity of the material obtained in Comparative Example 2 was only 32.3 mg / g, which is only 8.6% of that in Example 1. This indicates that under the same raw material composition, polyethylene glycol 4000 addition amount, and post-treatment conditions, the solid-phase reaction time has a significant impact on the structure formation and adsorption performance of the adsorbent material. Example 1 used a closed solid-phase reaction at 140℃ for 24 hours, while Comparative Example 2 shortened the reaction time to 8 hours. Since the solid-phase reaction process mainly relies on contact diffusion between solid particles to achieve element migration and crystal phase recombination, a shorter reaction time will lead to insufficient reaction between titanium tetrachloride, phosphate, and fluoride, and will not be able to fully construct a stable Ti-OP inorganic framework structure. At the same time, insufficient solid-phase reaction time will limit the regulatory effect of polyethylene glycol 4000 on particle packing behavior, resulting in incomplete development of the material's pore structure, a reduction in the number of open channels formed between particles, and a decrease in Sr in the solution. 2+ Diffusion into the material interior is limited. Furthermore, unreacted materials contain fewer effective active sites; phosphate groups, hydroxyl groups, etc., can react with Sr. 2+ The binding sites that are active are not adequately exposed, which leads to a significant reduction in adsorption capacity.

[0067] Comparing the adsorption capacity of the adsorbent material obtained in Example 1 with that obtained in Comparative Example 3 in Table 1, it can be seen that the Sr of the adsorbent material obtained in Example 1 is higher. 2+ The adsorption capacity reached 375.4 mg / g, while the material obtained in Comparative Example 3, which was not washed with ethanol, had an adsorption capacity of 272.6 mg / g, lower than that of the material obtained in Example 1. In Example 1, washing with deionized water and ethanol respectively effectively removed residual polyethylene glycol 4000 and some unreacted impurities, making the material pores more open and fully exposing the surface active sites. Comparative Example 3 did not use ethanol for washing; water washing alone was insufficient to completely remove the organic template agent and surface-adsorbed organic residues. (Regarding organic residues, during the washing process, it was found that after washing with deionized water and centrifuging, the supernatant was still turbid. After further washing with ethanol and centrifuging, the supernatant became clear, indicating that ethanol can further remove residual organic matter and attached fine particles from the material surface, improving the material purity. Residues may block some pores or cover adsorption sites, reducing Sr.) 2+ (Increases the contact opportunities with active groups such as phosphate groups and hydroxyl groups on the material surface). Therefore, the adsorption capacity of Comparative Example 3 in strontium solution decreased to 272.6 mg / g, which is lower than 375.4 mg / g of Example 1. This indicates that ethanol cleaning helps to remove organic residues, improve the exposure of pore structure, and enhance the adsorption performance of strontium ions.

[0068] The results in Tables 2 and 3 show that in Na + Ca 2+ Mg 2+ Under conditions of high concentrations of competing ions coexisting, the adsorbent material obtained in Example 1 still exhibits significant Sr... 2+ Preferential adsorption characteristics, Na+ in high-salt solutions + and Ca 2+ The initial concentrations reached 17435 ppm and 9294 ppm, respectively, far exceeding those of Sr. 2+ The initial concentration of Sr was 586 ppm, creating a highly competitive adsorption environment. After adsorption treatment, Sr... 2+ The concentration decreased from 586 ppm to 346 ppm, and the adsorption capacity reached 240 mg / g, indicating that the material can effectively capture Sr under high salt conditions. 2+ In contrast, Na + The concentration decreased only from 17435 ppm to 17426 ppm, with an adsorption capacity of only 9 mg / g; Ca 2+ The concentration decreased from 9294 ppm to 9264 ppm, and the adsorption capacity was 30 mg / g, indicating that the material effectively adsorbs high concentrations of Na. + and Ca 2+ It exhibits weak adsorption, effectively preventing the main competing ions from occupying a large number of adsorption sites. Based on the calculated adsorption selectivity coefficient, the adsorbent material obtained in Example 1 shows good adsorption for Sr. 2+ It has a significant preferential adsorption capacity, of which K Sr / Ca Reaching 214, K Sr / Na It reached 1343. This indicates that in Na... + Ca 2+ Even under conditions of high ion concentration, the material can still maintain its resistance to Sr. 2+ Selective enrichment ability for Mg. 2+ Its concentration decreased from 205 ppm to 120 ppm, showing a certain adsorption response, which may be related to Mg. 2+ This is related to its relatively small ionic radius and the complexation between oxygen-containing functional groups on its surface. However, in high concentrations of Na... + Ca 2+ In the coexistence system, the material of this invention still exhibits resistance to Sr. 2+ The preferential adsorption capacity indicates that the material has good resistance to salt interference.

[0069] Figure 1 This is a nitrogen adsorption-desorption isotherm curve of the adsorbent material obtained in Example 1. Figure 1It can be seen that the adsorption capacity of the material increases rapidly in the low relative pressure region, while a significant adsorption-desorption hysteresis phenomenon occurs in the medium-to-high relative pressure region, exhibiting typical type IV adsorption isotherm characteristics, indicating that the material has a rich mesoporous structure. Meanwhile, the specific surface area of ​​the adsorbent material obtained in Example 1 reached 292.48 m², as tested. 2 / g indicates that polyethylene glycol 4000 can effectively regulate particle packing behavior during solid-state reactions, promote the formation of open pore structures, and increase the contact area between the material and the solution, thus providing a basis for Sr 2+ Rapid diffusion and utilization of active sites provide the structural basis.

[0070] Figure 2 The image shows the X-ray diffraction pattern of the adsorbent material obtained in Example 1. Figure 2 The sample exhibits multiple distinct diffraction peaks with sharp peak shapes, indicating a good crystal structure. The characteristic diffraction peaks of anatase TiO2 (approximately 25.3°) and rutile TiO2 (approximately 27.4°) were not observed in the spectrum, suggesting that titanium tetrachloride did not form a distinct independent TiO2 crystal phase after solid-state heat treatment. Instead, it participated in a phosphate-related crystal phase reorganization process, rather than a simple physical mixing of raw materials.

[0071] Figure 3 This is a scanning electron microscope (SEM) image of the adsorbent material obtained in Example 1. Figure 3 It is evident that the material exhibits a loose and porous morphology, rather than a dense, massive structure. Numerous irregular pores exist on the surface, accompanied by an interwoven distribution of plate-like, rod-like, or tabular crystal structures, forming an open framework structure. This morphological characteristic indicates that during the solid-state reaction, the Ti and P components undergo structural reorganization, forming a relatively open particle packing mode under the regulation of polyethylene glycol 4000. The hierarchical porous structure facilitates the penetration of high-salt solutions into the material interior, increasing the Sr... 2+ This improves mass transfer efficiency and increases the exposure of effective adsorption sites.

[0072] Figure 4 This is the energy spectrum of the adsorbent material obtained in Example 1. Figure 4 It can be seen that the sample mainly detected characteristic peaks of Ti, P, and O elements, with no obvious signals of other impurity elements. This indicates that the obtained material is mainly composed of an inorganic system of Ti, P, and O, and no obvious inorganic impurities were generated during the reaction. Combined with the X-ray diffraction pattern, it can be further explained that the solid-state reaction promoted the formation of titanium phosphate functional structures, contributing to the material's excellent Sr... 2+ Adsorption properties provide the compositional basis.

[0073] The specific embodiments described above provide a further detailed explanation of the present invention; however, these descriptions should not be construed as limiting the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a strontium ion adsorption material for high-salinity wastewater, characterized in that, Includes the following steps: Step S01: Mix phosphate, fluoride, and polyethylene glycol, grind and mix evenly, add titanium tetrachloride, grind and mix evenly to obtain a mixed abrasive; Step S02: Place the mixed grinding material in a sealed reaction container for solid-phase reaction. After the reaction is completed, wash and dry to obtain strontium ion adsorption material for high-salt wastewater. In step S01, the molar ratio of titanium tetrachloride, phosphate, and fluoride is 1:3-6:0.1-0.4; The mass of polyethylene glycol is 5-8% of the mass of titanium tetrachloride.

2. The preparation method of the strontium ion adsorption material for high-salinity wastewater according to claim 1, characterized in that, In step S01, the phosphate is one or a combination of ammonium hydrate phosphate and ammonium dihydrogen phosphate; The fluoride salt is one or a combination of ammonium fluoride and ammonium bifluoride; The polyethylene glycol is polyethylene glycol 2000-6000.

3. The preparation method of the strontium ion adsorption material for high-salinity wastewater according to claim 1, characterized in that, In step S01, titanium tetrachloride is added dropwise while stirring.

4. The preparation method of the strontium ion adsorption material for high-salinity wastewater according to claim 1, characterized in that, In step S01, the grinding method used to grind and mix the materials evenly is manual grinding.

5. The method for preparing strontium ion adsorption material for high-salinity wastewater according to claim 1, characterized in that, In step S02, the reaction temperature of the solid-phase reaction is 120-150℃, and the reaction time is 12-24h.

6. The method for preparing strontium ion adsorption material for high-salinity wastewater according to claim 1, characterized in that, In step S02, the washing solution used is deionized water and ethanol. The washing conditions are to wash with deionized water 1-2 times, and then wash with ethanol 1-2 times.

7. The preparation method of the strontium ion adsorption material for high-salinity wastewater according to claim 1, characterized in that, In step S02, the drying temperature is 60-80℃ and the drying time is 4-6 hours.

8. A strontium ion adsorption material for high-salt wastewater prepared by the preparation method according to any one of claims 1-7.

9. An application of a strontium ion adsorption material for high-salinity wastewater prepared by the preparation method according to any one of claims 1-7, characterized in that, Includes the following steps: Strontium ion adsorption material for high-salt wastewater is added to a high-salt strontium-containing solution for adsorption. After adsorption is completed, solid-liquid separation is performed to obtain the material after adsorbing strontium ions and the treated solution.

10. The application of the strontium ion adsorption material for high-salinity wastewater according to claim 9, characterized in that, The high-salt strontium-containing solution contains Sr 2+ and competing ions, said competing ions including Na + Ca 2+ Mg 2+ One or a combination thereof; The amount of strontium ion adsorption material added to the high-salt wastewater strontium-containing solution is 0.5-2 g / L.

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