High-hydrophilicity titanium-based lithium ion sieve based on synergistic surface and lattice regulation and preparation method of high-hydrophilicity titanium-based lithium ion sieve

Abstract

The invention belongs to the technical field of inorganic functional materials, and particularly discloses a preparation technology of a titanium adsorbent, namely a high-hydrophilicity titanium-based lithium ion sieve based on synergistic surface and lattice regulation and a preparation method thereof, the preparation method comprises the following steps: adding lauryl sodium sulfate and thiourea into a solvent, and fully dissolving to obtain a solution A; adding tetrabutyl titanate into the solution A, and uniformly mixing to obtain a solution B; adding a LiOH solution into the solution B, and uniformly mixing to obtain uniformly mixed turbid liquid; placing the turbid liquid in a high-pressure reaction kettle for reaction, and sequentially performing drying and heat treatment to obtain a precursor Li2TiO3; and adding the precursor Li2TiO3 into hydrochloric acid, and carrying out vibration leaching to obtain the high-hydrophilicity titanium-based lithium ion sieve. The titanium-based lithium ion sieve prepared by the preparation method disclosed by the invention can ensure high adsorption capacity, also has extremely high adsorption rate, is good in chemical stability and can be repeatedly used.

Description

Technical Field

[0001] This invention belongs to the field of inorganic functional materials technology, specifically relating to a preparation technology of titanium-based adsorbents; more specifically, it relates to a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation and its preparation method. Background Technology

[0002] With the continuous growth in demand for lithium resources, liquid-phase lithium extraction technology has become an important means of achieving efficient lithium resource recovery due to its advantages such as high selectivity, low energy consumption, and environmental friendliness. Among them, titanium-based lithium-ion sieve materials, with their excellent structural stability and green and non-toxic properties, have been widely regarded as one of the most promising adsorbent materials for liquid lithium extraction. However, in practical applications, titanium-based adsorbents still face problems such as low adsorption rate and long adsorption equilibrium time, which seriously restricts their promotion and application in industrial lithium extraction processes. Therefore, improving the adsorption performance of titanium-based lithium-ion sieves, especially the adsorption rate and efficiency, has become a technical challenge that urgently needs to be overcome.

[0003] Currently, research on the modification of H₂TiO₃ (HTO) mainly focuses on single strategies such as metal element doping or surface modification. While these strategies can improve the adsorption capacity of the material to some extent, they often fail to achieve the desired adsorption rate and capacity simultaneously, thus limiting breakthroughs in its overall performance and enhanced practicality. For example, patent CN119549135A discloses a high-valence Nb... 5+ A method for preparing doped H₂TiO₃ lithium-ion sieves utilizes hollow structure and high specific surface area anatase TiO₂ as the titanium source, significantly improving the material's specific surface area, porosity, and particle dispersion, increasing adsorption active sites, and thus enhancing the lithium-ion adsorption capacity. However, this material requires over 20 hours to reach adsorption equilibrium, and the adsorption rate still falls short of the requirements for rapid industrial recycling. Furthermore, patent CN119771336A modifies titanium-based ion sieves by introducing citric acid as a surfactant, obtaining an adsorbent with high crystallinity, fine particles, and uniform distribution, achieving an adsorption capacity of 41.84 mg g. -1 However, its adsorption process also requires more than 5 hours to reach equilibrium, and there is still considerable room for improvement in adsorption kinetics.

[0004] Therefore, developing a titanium-based lithium-ion sieve synergistic modification technology with reasonable structural design, synergistically optimized performance, and simple and feasible process has become a key breakthrough for promoting the industrialization of liquid phase lithium extraction technology. Summary of the Invention

[0005] In view of the above-mentioned problems, this invention provides a highly hydrophilic titanium-based lithium-ion sieve and its preparation method based on synergistic surface and lattice regulation. This invention significantly improves the specific surface area, hydrophilicity, and defect structure of the material through the synergistic effect of multiple dimensions such as morphology regulation, surface functionalization, and lattice structure regulation, promoting rapid desolvation and diffusion migration of lithium ions. This achieves comprehensive lithium extraction performance with high capacity, high rate, and high cycling stability, meeting the application requirements for efficient lithium extraction in complex salt lake brine systems. Compared with single modification strategies, it maintains high adsorption capacity while also exhibiting an extremely fast adsorption rate, reaching adsorption equilibrium within 1 hour.

[0006] To address the aforementioned problems, this invention provides a method for preparing a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation, comprising the following steps: S1. Sodium dodecyl sulfate and thiourea are added to a solvent and dissolved completely to obtain solution A; tetrabutyl titanate is added to solution A and mixed to obtain solution B; S2. Add LiOH solution to solution B, and after mixing, a uniform suspension is obtained; S3. After the suspension is placed in a high-pressure reactor for reaction, it is then dried and heat-treated sequentially to obtain the precursor Li2TiO3; S4. The precursor Li2TiO3 is added to hydrochloric acid and leached by shaking to obtain a highly hydrophilic titanium-based lithium ion sieve SDS-HTO-TU.

[0007] Preferably, in step S1, the solvent includes at least one of anhydrous ethanol, acetylacetone, and tetrahydrofuran.

[0008] Preferably, the mass ratio of sodium dodecyl sulfate to tetrabutyl titanate is 5-15:100.

[0009] Preferably, the mass ratio of the thiourea to the tetrabutyl titanate is 5-15:100.

[0010] Preferably, the molar ratio of tetrabutyl titanate to LiOH is 1:1.5-2.5, and the concentration of the LiOH solution is 1.5-2.5M.

[0011] Preferably, in step S3, the reaction temperature in the high-pressure reactor is 150-180℃, and the reaction time is 8-15h.

[0012] Preferably, in step S3, the drying temperature is 40-70℃ and the time is 8-15h.

[0013] Preferably, in step S3, the heat treatment temperature is 500-700℃ and the time is 3-6h.

[0014] Preferably, in step S4, the concentration of hydrochloric acid is 0.1-0.3M; and the shaking leaching time is 3-8 hours.

[0015] Based on the same inventive concept, the present invention also provides a highly hydrophilic titanium-based lithium ion sieve prepared by any of the preparation methods described above.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention achieves surface etching and functional modification of lithium ion sieves by thiourea doping and synergistic surfactant-assisted dispersion, thereby improving hydrophilicity and increasing active sites, thus enhancing its adsorption rate and adsorption capacity for lithium ions. (2) The synergistic effect of SDS and TU in this invention induces the generation of oxygen vacancies, optimizes crystal structure defects, improves the diffusion channel of lithium ions in the material, thereby significantly shortening the adsorption equilibrium time and improving the adsorption kinetic performance. (3) Compared with existing technologies CN119549135A (adsorption equilibrium can be reached in 5 hours) and CN119771336A (adsorption equilibrium can be reached in 20 hours), the lithium-ion sieve adsorbent in this invention maintains a high adsorption capacity (42.8 mg g). -1 At the same time, it also has an extremely fast adsorption rate, reaching adsorption equilibrium in about 1 hour.

[0017] (4) Compared with the prior art CN101955210B (hydrochloric acid concentration of 1 mol / L), the hydrochloric acid concentration in the present invention is low (0.1-0.3M), which is beneficial to saving costs; the hydrochloric acid concentration in Example 1 of the present invention is 0.2M, but its lithium ion sieve adsorbent maintains 93.85% of the initial value after 10 cycles, indicating that even if the hydrochloric acid concentration is low, the present invention will not affect the reusability and chemical stability of the lithium ion sieve adsorbent. Attached Figure Description

[0018] Figure 1 The XRD patterns are of the precursors prepared in Example 1 and Comparative Examples 1-3 of this invention. Figure 2 The image shows a SEM image of the precursor SDS-LTO-TU prepared in Example 1 of this invention. Figure 3 XPS images of the titanium-based lithium-ion sieves prepared in Example 1 and Comparative Examples 1-3 of this invention; where (a) N 1s; (b) O 1s; (c) S 2p; Figure 4 The oxygen vacancy content diagram is obtained by fitting the XPS peak of the titanium-based lithium ion sieves prepared in Example 1 and Comparative Examples 1-3 of the present invention. Figure 5 The images show the contact angle test results of the titanium-based lithium-ion sieves prepared in Example 1 and Comparative Examples 1-3 of this invention; where (a) is Comparative Example 2; (b) is Comparative Example 1; (c) is Comparative Example 3; and (d) is Example 1. Figure 6 The curves show the change in lithium adsorption capacity over time for the titanium-based lithium ion sieves prepared in Example 1 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0019] To make the present invention easier to understand, specific embodiments are described below to further illustrate the invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical terms used below have the same meaning as understood by those skilled in the art; unless otherwise specified, the raw materials and reagents involved herein can be purchased commercially or obtained by known methods.

[0020] It should be noted that in this invention, sodium dodecyl sulfate is abbreviated as SDS, thiourea as TU, Li2TiO3 as LTO, and H2TiO3 as HTO.

[0021] To develop a synergistic modification technology for titanium-based lithium-ion sieves with a reasonable structural design, synergistically optimized performance, and simple and feasible process, this invention provides a method for preparing highly hydrophilic titanium-based lithium-ion sieves based on synergistic surface and lattice regulation, comprising the following steps: S1. Sodium dodecyl sulfate and thiourea are added to a solvent and dissolved completely to obtain solution A; tetrabutyl titanate is added to solution A and mixed to obtain solution B; S2. Add LiOH solution to solution B, and after mixing, a uniform suspension is obtained; S3. After the suspension is placed in a high-pressure reactor for reaction, it is then dried and heat-treated sequentially to obtain the precursor Li2TiO3; S4. The precursor Li2TiO3 is added to hydrochloric acid and leached by shaking to obtain a highly hydrophilic titanium-based lithium ion sieve SDS-HTO-TU.

[0022] In some specific implementations, in step S1, the solvent includes at least one of anhydrous ethanol, acetylacetone, and tetrahydrofuran.

[0023] In some specific embodiments, the mass ratio of sodium dodecyl sulfate to tetrabutyl titanate is 5-15:100.

[0024] In some specific embodiments, the mass ratio of the thiourea to the tetrabutyl titanate is 5-15:100.

[0025] In some specific embodiments, the molar ratio of tetrabutyl titanate to LiOH is 1:1.5-2.5, and the concentration of the LiOH solution is 1.5-2.5M.

[0026] In some specific implementations, in step S3, the reaction temperature in the high-pressure reactor is 150-180℃, and the time is 8-15h.

[0027] In some specific implementations, in step S3, the drying temperature is 40-70°C and the time is 8-15 hours.

[0028] In some specific implementations, in step S3, the heat treatment temperature is 500-700℃ and the time is 3-6h.

[0029] In some specific implementations, in step S4, the concentration of hydrochloric acid is 0.1-0.3M; and the shaking immersion time is 3-8 hours.

[0030] The present invention also provides a highly hydrophilic titanium-based lithium ion sieve prepared by any of the preparation methods described above.

[0031] The following examples and comparative models further illustrate this point.

[0032] Example 1

[0033] A method for preparing a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation includes the following steps: S1. Add 0.1g sodium dodecyl sulfate (SDS) and 0.05g thiourea (TU) to 10mL of anhydrous ethanol, and sonicate for 10min to completely dissolve the thiourea and sodium dodecyl sulfate to obtain solution A; then add 1g tetrabutyl titanate to solution A and stir until the mixture is homogeneous to obtain solution B.

[0034] S2. Add 3 mL of 2 M LiOH solution to solution B and stir and disperse on a magnetic stirrer for 1 h to obtain a uniformly mixed suspension; S3. The suspension was placed in a high-pressure reactor and reacted at 170°C for 12 hours to obtain a white precipitate. The precipitate was dried at 60°C for 12 hours and then heat-treated in air at 600°C for 3 hours to obtain the precursor Li2TiO3 (SDS-LTO-TU). S4. The precursor Li2TiO3 is added to 0.2M hydrochloric acid and leached by shaking for 3 hours to obtain a highly hydrophilic titanium-based lithium ion sieve SDS-HTO-TU.

[0035] Example 2

[0036] The difference between this embodiment and Embodiment 1 is that the thiourea content is 0.1g. Other steps and parameters are the same as in Embodiment 1.

[0037] Example 3

[0038] The difference between this embodiment and Example 1 is that the sodium dodecyl sulfate content is 0.05g. Other steps and parameters are the same as in Example 1.

[0039] Example 4

[0040] The difference between this embodiment and Embodiment 1 is that the shaking immersion in step S4 lasts for 8 hours. Other steps and parameters are the same as in Embodiment 1.

[0041] Example 5

[0042] The difference between this embodiment and Embodiment 1 is that the concentration of the LiOH solution in step S2 is 1.5M. Other steps and parameters are the same as in Embodiment 1.

[0043] Comparative Example 1

[0044] The difference between this comparative example and Example 1 is that thiourea was not added. Other steps and parameters are the same as in Example 1. The intermediate precursor obtained is SDS-LTO, and the final product is titanium-based lithium ion sieve SDS-LHO.

[0045] Comparative Example 2

[0046] The difference between this comparative example and Example 1 is that sodium dodecyl sulfate and thiourea were not added. Other steps and parameters are the same as in Example 1. The intermediate precursor obtained is LTO, and the final product is a titanium-based lithium ion sieve, LHO.

[0047] Comparative Example 3

[0048] The difference between this comparative example and Example 1 is that sodium dodecyl sulfate was not added. Other steps and parameters are the same as in Example 1, except that the intermediate precursor obtained is LTO-TU, and the final product is the titanium-based lithium ion sieve LHO-TU.

[0049] Comparative Example 4

[0050] The difference between this comparative example and Example 1 is that the concentration of hydrochloric acid in step S4 is 0.05M. Other steps and parameters are the same as in Example 1.

[0051] Comparative Example 5

[0052] The difference between this comparative example and Example 1 is that the shaking immersion in step S4 lasts for 12 hours. Other steps and parameters are the same as in Example 1.

[0053] Comparative Example 6

[0054] The difference between this comparative example and Example 1 is that the concentration of the LiOH solution in step S2 is 6M. Other steps and parameters are the same as in Example 1.

[0055] Performance testing and results analysis: The precursors prepared in Example 1 and Comparative Examples 1-3 were analyzed by X-ray diffraction (XRD), and the results are as follows: Figure 1 As shown. By Figure 1 It can be seen that the precursor results obtained in Example 1 and Comparative Examples 1-3 are consistent with the standard card of layered Li2TiO3.

[0056] The precursor prepared in Example 1 was analyzed by scanning electron microscopy (SEM), and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the surface of the precursor SDS-LTO-TU prepared in Example 1 of the present invention has a secondary microsphere structure, which is due to the etching effect of the surfactant, resulting in small and uniform particles.

[0057] The titanium-based lithium-ion sieves prepared in Example 1 and Comparative Examples 1-3 were analyzed by X-ray photoelectron spectroscopy (XPS), and the results are as follows: Figure 3 As shown. By Figure 3 As can be seen, in Example 1 and Comparative Example 1, N was intermittently doped, and the characteristic peak of S was observed to be near 169 eV, which is the characteristic peak of sulfate ions; however, no such phenomenon was observed in Comparative Examples 2-3. This indicates that the thiourea of ​​the present invention can achieve intermittent N doping while generating sulfate ions.

[0058] The above Figure 3 The XPS peaks were fitted to obtain the oxygen vacancy content as shown in the figure. Figure 4 As shown. By Figure 4 It is known that both thiourea and sodium dodecyl sulfate of the present invention can increase oxygen vacancies, and Example 1 of the present invention has more oxygen vacancies than Comparative Examples 1-3, thereby further promoting the diffusion process of ions.

[0059] The contact angle of the titanium-based lithium-ion sieves prepared in Example 1 and Comparative Examples 1-3 was measured and analyzed, and the results are as follows: Figure 5 As shown. By Figure 5It can be seen that the contact angle of the titanium-based lithium-ion sieve prepared in Example 1 is 18.3°; the contact angle of the titanium-based lithium-ion sieve prepared in Comparative Example 1 is 23.3°; the contact angle of the titanium-based lithium-ion sieve prepared in Comparative Example 2 is 38.9°; and the contact angle of the titanium-based lithium-ion sieve prepared in Comparative Example 3 is 28.3°. This indicates that both thiourea and sodium dodecyl sulfate of the present invention can reduce their contact angles, and Example 1 of the present invention has better hydrophilicity than Comparative Examples 1-3, which can better accelerate the adsorption rate of lithium ions.

[0060] The titanium-based lithium-ion sieves prepared in Example 1 and Comparative Examples 1-3 were respectively placed in an initial lithium-ion concentration of 120 mg / L. -1 The adsorbent solution (prepared by dissolving 0.239 g of LiOH and 0.309 g of LiCl in 1 L of deionized water) was used to prepare a solution with pH=12 and LiCl. + The concentration is 120 mg / L -1 Adsorption tests were conducted in the adsorption solution at 293 K, and the results are as follows: Figure 6 As shown. By Figure 6 It can be seen that the titanium-based lithium ion sieve SDS-LHO-TU prepared in Example 1 has a positive effect on Li... + The adsorption capacity is 42.8 mg g. -1 The adsorption equilibrium time is only 1 hour; the titanium-based lithium ion sieve SDS-LHO prepared in Comparative Example 1 has a high adsorption capacity for Li... + The adsorption capacity is 36.7 mg g. -1 The adsorption equilibrium time requires 2 hours; the titanium-based lithium ion sieve LHO prepared in Comparative Example 2 has a high adsorption capacity for Li... + The adsorption capacity is 30.6 mg g. -1 The adsorption equilibrium time requires 5 hours; the titanium-based lithium ion sieve LHO-TU prepared in Comparative Example 3 has a high adsorption capacity for Li... + The adsorption capacity is 38.7 mg g. -1 The adsorption equilibrium time is 3 hours. Among them, the titanium-based lithium ion sieve SDS-LHO-TU prepared in Example 1 has a lithium extraction rate as high as 94.7% and a titanium dissolution rate of only 0.33%.

[0061] Simultaneously, the same method was used to place the titanium-based lithium ion sieves prepared in Examples 2-5 and Comparative Examples 4-6 into an initial lithium ion concentration of 120 mg / L. -1 The adsorbent solution (prepared by dissolving 0.239 g of LiOH and 0.309 g of LiCl in 1 L of deionized water) was used to prepare a solution with pH=12 and LiCl. + The concentration is 120 mg / L -1In the adsorption solution, adsorption tests were conducted at 293 K, and the titanium-based lithium ion sieve SDS-LHO-TU prepared in Example 2 showed that it effectively adsorbed Li-ion onto Li-ion batteries. + The adsorption capacity is 40.1 mg g. -1 Example 3 shows the preparation of the titanium-based lithium-ion sieve SDS-LHO-TU for Li... + The adsorption capacity is 38.7 mg g. -1 Example 5 shows the preparation of the titanium-based lithium-ion sieve SDS-LHO-TU for Li... + The adsorption capacity is 40.7 mg g. -1 Comparative Example 1 prepared titanium-based lithium-ion sieve SDS-LHO-TU for Li + The adsorption capacity is 37.9 mg g. -1 Among them, the titanium-based lithium ion sieve SDS-LHO-TU prepared in Example 4 had a lithium extraction rate as high as 94.8% and a titanium dissolution rate of only 0.35%; the titanium-based lithium ion sieve SDS-LHO-TU prepared in Comparative Example 4 had a lithium extraction rate of 59.3% and a titanium dissolution rate of 0.16%; the titanium-based lithium ion sieve SDS-LHO-TU prepared in Comparative Example 5 had a lithium extraction rate of 94.8% and a titanium dissolution rate of 0.46% (the titanium dissolution rate was too high).

[0062] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation, characterized in that, Includes the following steps: S1. Add sodium dodecyl sulfate and thiourea to the solvent, and after complete dissolution, obtain solution A; Tetrabutyl titanate was added to solution A, and after mixing, solution B was obtained. S2. Add LiOH solution to solution B, and after mixing, a uniform suspension is obtained; S3. After the suspension is placed in a high-pressure reactor for reaction, it is then dried and heat-treated sequentially to obtain the precursor Li2TiO3; S4. The precursor Li2TiO3 is added to hydrochloric acid and leached by shaking to obtain a highly hydrophilic titanium-based lithium ion sieve SDS-HTO-TU.

2. The preparation method of the highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 1, characterized in that, In step S1, the solvent includes at least one of anhydrous ethanol, acetylacetone, and tetrahydrofuran.

3. The preparation method of the highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 1, characterized in that, The mass ratio of sodium dodecyl sulfate to tetrabutyl titanate is 5-15:

100.

4. The preparation method of the highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 1, characterized in that, The mass ratio of the thiourea to the tetrabutyl titanate is 5-15:

100.

5. The preparation method of the highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 4, characterized in that, The molar ratio of tetrabutyl titanate to LiOH is 1:1.5-2.5, and the concentration of the LiOH solution is 1.5-2.5M.

6. The method for preparing a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 1, characterized in that, In step S3, the reaction in the high-pressure reactor is carried out at a temperature of 150-180℃ for 8-15 hours.

7. The method for preparing a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 1, characterized in that, In step S3, the drying temperature is 40-70℃ and the time is 8-15h.

8. The method for preparing a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 1, characterized in that, In step S3, the heat treatment temperature is 500-700℃ and the time is 3-6h.

9. The method for preparing a highly hydrophilic titanium-based lithium-ion sieve based on synergistic surface and lattice regulation according to claim 1, characterized in that, In step S4, the concentration of hydrochloric acid is 0.1-0.3M; the shaking leaching time is 3-8 hours.

10. A highly hydrophilic titanium-based lithium ion sieve prepared by the preparation method according to any one of claims 1-9.

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