A super-hydrophilic titanium-based spinel lithium ion sieve material and preparation method thereof

Abstract

The present invention provides a super-hydrophilic titanium-based spinel lithium ion sieve material and a preparation method thereof, belonging to the field of lithium resource utilization materials. The lithium ion sieve prepared by the present invention is composed of ultra-thin H4Ti5O 12 The synthesis method of this material is to use butyl titanate and lithium hydroxide as raw materials, add cetyltrimethylammonium bromide (CTAB), hexadecylamine (HDA) and polypropylene glycol and ethylene oxide (F127) as templates, and hydrothermally heat the precursor Li4Ti5O 12 , and then generate spinel H4Ti5O by acid leaching 12 Lithium ion sieve. This material has excellent surface hydrophilicity and an open multi-level mesoporous structure, which realizes Li + With H + Rapid ion exchange, the material has a simple preparation method, good Li + The adsorption performance and cyclic stability show good application prospects in the field of lithium extraction from salt lakes.

Description

Technical Field

[0001] The invention provides a super-hydrophilic titanium-based spinel lithium ion sieve material and a preparation method thereof. The material belongs to the field of lithium ion resource utilization. Background Art

[0002] With the rapid development of the global economy and the increasing demand for high-tech products such as electric vehicles, portable electronic devices, power tools, and renewable energy storage devices, the demand for lithium resources has skyrocketed. In 2022, the battery industry consumed the largest share of global lithium resources, reaching 74%. Due to the rising cost of lithium ore mining, high energy consumption, and the resulting environmental problems such as land destruction and water pollution, liquid lithium resources have attracted increasing attention. Salt lake brine accounts for 61.8% of global lithium resources, leading many researchers to focus on extracting lithium from liquid lithium resources such as salt lake brine, seawater, groundwater, and saline wastewater.

[0003] At present, the main methods for extracting liquid lithium include precipitation, solvent extraction, nanofiltration, electrochemical method and adsorption method. Among these methods, adsorption method has the advantages of low energy consumption, economy and environmental protection, and is considered to be the most promising method for extracting lithium from liquid lithium resources. Lithium ion sieve adsorbent is the key to adsorption method. So far, the most studied ones are manganese oxide ion sieves (HMn2O4, H 1.33 Mn 1.67 O4、H 1.6 Mn 1.6 O4) and titanium oxide ion sieves (H2TiO3, H4Ti5O 12 ) Two types. Spinel manganese oxide ion sieve has many advantages such as high adsorption capacity and good selectivity, but Mn 3+ The disproportionation reaction, Jahn-Teller effect and high manganese dissolution rate have always been the problems that need to be solved, which seriously affect its industrial application process. 12 The spinel-type titanium oxide ion sieve represented by is simple to prepare and has good chemical stability during acid leaching. It is considered to be a green and environmentally friendly adsorbent that is superior to manganese oxide ion sieve.

[0004] At present, there have been relevant reports on the application of spinel titanium oxide ion sieves in the field of lithium resource recovery. For example, Dong Dianquan et al. used the sol-gel method to obtain spinel structured H4Ti5O 12 The ion sieve exchange Li was successfully described using the shrinking core model. + The dynamics of the lithium ion sieve was found to be controlled by particle diffusion (Dong Dianquan et al. Li4Ti5O 12 Synthesis and treatment of Li +Ion Exchange Kinetics, 2007, 23(6):950-954.); Yan Hui et al. ball-milled TiO2 and Li2CO3 and then calcined and acid-washed to obtain titanium-based lithium ion sieve H4Ti5O 12 , and its saturated adsorption capacity reaches 32.29 mg / g (Yan Hui et al. Preparation of new lithium adsorbents, Inorganic Salt Industry, 2014, 46(2):38-40.). The above work shows that spinel titanium oxide H4Ti5O 12 The ion sieve has good lithium ion adsorption capacity, but the adsorption capacity of the lithium ion sieve is far lower than its theoretical adsorption capacity, indicating that some means are needed to enhance the spinel titanium oxide H4Ti5O 12 The adsorption capacity of the ion sieve can be improved by increasing the specific surface area and hydrophilicity of the material.

[0005] In order to increase the spinel titanium oxide H4Ti5O 12 The adsorption capacity of ion sieves can be improved by changing the surface morphology of the material to increase the specific surface area of ​​the material. For example, Moazeni et al. prepared nanotube-structured H4Ti5O by a two-step hydrothermal reaction. 12 , with an adsorption capacity of 39.43 mg / g (Moazeni, H. et al. Hydrothermal synthesis and characterization of titanium dioxide nanotubes as novel lithium adsorbents, Materials Research Bulletin 2015, 61: 70-75.). Recent studies have also found that the hydrophilicity of titanium-based lithium ion sieves has a significant impact on their adsorption capacity. For example, Zhu et al. found that titanium-based lithium ion sieves with the highest hydrophilicity have the highest lithium ion adsorption capacity (Zhu wenshuai et al. Preparation of high hydrophilic H2TiO3 ionsieve for lithium recovery from liquid lithium resources, Chemical engineering journal 2023, 453: 139485.). The addition of a template agent is beneficial for improving the wettability of the titanium-based lithium ion sieve material surface, thereby enhancing the lithium ion adsorption capacity of the material. Summary of the Invention

[0006] In order to realize the extraction of lithium resources from liquids such as salt lake brine, seawater, underground brine and saline wastewater, the present invention provides a super hydrophilic titanium-based spinel lithium ion sieve material and a preparation method thereof.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] Step 1: Weigh 1-5 g of a surfactant and place it in 10-30 mL of an ethanol solution. After stirring, add 10-30 mL of butyl titanate, prepare a 1-3 mol / L lithium hydroxide solution, add it dropwise to the butyl titanate solution according to a stoichiometric ratio, and stir at room temperature for 5-60 minutes to obtain a mixed suspension.

[0009] Step 2: The mixed suspension of step 1 was transferred into a 100 mL solvent thermal reactor, and the solvent thermal reaction was carried out at a high temperature of 160-200 ° C for 10-30 hours. After solid-liquid separation, it was washed with ultrapure water three times, dried at 50-60 ° C for 6 hours, and calcined at 300-700 ° C for 3-8 hours, and then ground to obtain Li4Ti5O 12 ;

[0010] Step 3: 1-5g of Li4Ti5O obtained in step 2 12 The sample is immersed in a 0.1-0.5 mol / L hydrochloric acid solution for 20-30 hours to obtain a super-hydrophilic titanium-based spinel lithium ion sieve material.

[0011] The present invention has the following advantages and beneficial effects: the material can reach an adsorption capacity of 40.84 mg / g after adsorption within 30 minutes, and the saturated adsorption capacity can reach 59.38 mg / g after increasing the lithium ion concentration; + , K + , Ca 2+ Mg 2+ ) blend, the amount of lithium ion adsorption showed no significant attenuation, demonstrating that the material can effectively separate lithium ions in an environment with multiple impurity cations. Cycling tests showed that the lithium ion adsorption capacity remained at 97% after five cycles, demonstrating the material's excellent cycling performance. Compared to other lithium adsorbents, this material rapidly adsorbs lithium ions, exhibits excellent lithium ion screening and cycling performance, and offers advantages such as simple preparation and high adsorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the XRD spectrum of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention.

[0013] Figure 2 This is an SEM image of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention.

[0014] Figure 3 This is a static contact angle diagram of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention.

[0015] Figure 4This is a graph showing the lithium ion adsorption rate of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention at different times.

[0016] Figure 5 This is a comparison chart of lithium ion adsorption rates of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention in the coexistence of multiple impurity metal ions.

[0017] Figure 6 This is an adsorption cycle performance diagram of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying examples.

[0019] Example 1

[0020] A super-hydrophilic titanium-based spinel lithium ion sieve material and its preparation method. 1g of hexadecyltrimethylammonium bromide and 2g of hexadecylamine surfactant were weighed and placed in 10mL of ethanol solution. After stirring, 30mL of butyl titanate was added. A 3mol / L lithium hydroxide solution was prepared and added dropwise to the butyl titanate solution according to a stoichiometric ratio. The mixture was stirred at room temperature for 5 minutes to obtain a mixed suspension. The mixed suspension was transferred to a 100mL solvent thermal reactor and subjected to solvent thermal reaction at 160°C for 10 hours. After solid-liquid separation, the mixture was washed three times with ultrapure water, dried at 60°C for 6 hours, calcined at 300°C for 8 hours, and then ground to obtain Li4Ti5O 12 1g of Li4Ti5O 12 The sample was immersed in a 0.5 mol / L hydrochloric acid solution for 20 hours to obtain a super-hydrophilic titanium-based spinel lithium ion sieve material.

[0021] Example 2

[0022] A super-hydrophilic titanium-based spinel lithium ion sieve material and its preparation method. 2g of hexadecyltrimethylammonium bromide and 2g of a surfactant (polypropylene glycol and ethylene oxide) were weighed and placed in a 30mL ethanol solution. After stirring, 10mL of butyl titanate was added. A 1mol / L lithium hydroxide solution was prepared and added dropwise to the butyl titanate solution according to a stoichiometric ratio. The mixture was stirred at room temperature for 30 minutes to obtain a mixed suspension. The mixed suspension was transferred to a 100mL solvent thermal reactor and subjected to solvent thermal reaction at 200°C for 30 hours. After solid-liquid separation, the mixture was washed three times with ultrapure water, dried at 50°C for 6 hours, calcined at 700°C for 3 hours, and then ground to obtain Li4Ti5O 12 5g of Li4Ti5O 12 The sample was immersed in a 0.1 mol / L hydrochloric acid solution for 30 hours to obtain a super-hydrophilic titanium-based spinel lithium ion sieve material.

[0023] Example 3

[0024] A super-hydrophilic titanium-based spinel lithium ion sieve material and its preparation method. 1g of hexadecyltrimethylammonium bromide and 2g of a surfactant (polypropylene glycol and ethylene oxide) were weighed and placed in a 20mL ethanol solution. After stirring, 20mL of butyl titanate was added. A 2mol / L lithium hydroxide solution was prepared and added dropwise to the butyl titanate solution according to a stoichiometric ratio. The mixture was stirred at room temperature for 60 minutes to obtain a mixed suspension. The mixed suspension was transferred to a 100mL solvent thermal reactor and subjected to solvent thermal reaction at 180°C for 24 hours. After solid-liquid separation, the mixture was washed three times with ultrapure water, dried at 50°C for 6 hours, calcined at 600°C for 4 hours, and then ground to obtain Li4Ti5O 12 1.5g of Li4Ti5O 12 The sample was immersed in a 0.2 mol / L hydrochloric acid solution for 24 hours to obtain a super-hydrophilic titanium-based spinel lithium ion sieve material.

[0025] Taking Example 3 as an example, Figure 1 The XRD spectrum of the obtained sample is shown in Figure 2. It can be seen that the XRD spectrum of the obtained sample is similar to that of the spinel H4Ti5O 12 PDF#49-0207 matches well, indicating that this method prepared spinel H4Ti5O 12 Material.

[0026] Figure 2 The obtained H4Ti5O 12 SEM image of the material. The prepared sample is a micro-scale sphere assembled by many ultra-thin nanosheets. The size of the microsphere is 5-7 μm. Li is eluted with hydrochloric acid. + The morphology of the material did not change significantly, indicating that its structure was relatively stable, which was conducive to the recycling of the adsorbent.

[0027] Figure 3 This is a static contact angle diagram of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention. The contact angle of the material is less than 10°, indicating that the surface of the material has super-hydrophilicity.

[0028] Figure 4 This is a graph showing the lithium ion adsorption rate of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention at different times. The material can reach an adsorption amount of 40.84 mg / g after adsorption in a 400 mg / L lithium elemental solution within 30 minutes, and the adsorption equilibrium capacity is 47.38 mg / g.

[0029] Figure 5 This is a comparison chart of the lithium ion adsorption rate of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention in the presence of multiple impurity metal ions. + Has high adsorption selectivity, especially mg 2+The distribution coefficient is only 0.43, and the separation factor of lithium ions to magnesium ions reaches 135.56.

[0030] Figure 6 This is the adsorption cycle performance diagram of the super-hydrophilic titanium-based spinel lithium ion sieve material prepared by the present invention. The adsorbent loses 3% of its adsorption capacity after five adsorption and desorption cycles, and Ti 4+ The dissolution loss rate is kept at 0.2%, indicating that the material has good stability and cycle performance.

[0031] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformation using the contents of the present invention's description and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A super-hydrophilic titanium-based spinel lithium ion sieve material, characterized by: Made of ultra-thin H4Ti5O 12 The nanosheets are assembled into microspheres in layers, with a size of 5-10 μm. The preparation method of the super-hydrophilic titanium-based spinel lithium ion sieve material comprises the following steps: Step 1: Weigh 1-5 g of a surfactant and place it in 10-30 mL of an ethanol solution. After stirring, add 10-30 mL of butyl titanate, prepare a 1-3 mol / L lithium hydroxide solution, add the solution dropwise to the butyl titanate solution in a stoichiometric ratio, and stir at room temperature for 5-60 minutes to obtain a mixed suspension. Step 2: The mixed suspension of step 1 was transferred into a 100 mL solvent thermal reactor, and the solvent thermal reaction was carried out at a high temperature of 160-200 ° C for 10-30 hours. After solid-liquid separation, it was washed with ultrapure water three times, dried at 50-60 ° C for 6 hours, and calcined at 300-700 ° C for 3-8 hours, and then ground to obtain Li4Ti5O 12 ; Step 3: Obtain 1~5g of Li4Ti5O through step 2 12 The sample was immersed in a 0.1-0.5 mol / L hydrochloric acid solution for 20-30 hours to obtain a super-hydrophilic titanium-based spinel lithium ion sieve material; The surfactants are cetyltrimethylammonium bromide and hexadecylamine.

Images