阅读说明：本技术 一种选择性提取锂的钛基离子筛及制备方法和应用 (Titanium-based ion sieve for selectively extracting lithium, preparation method and application ) 是由 宋志强 郑旭东 王彬 程倩 卞婷婷 张奕 李忠玉 于 2020-06-02 设计创作，主要内容包括：本发明属于环境材料制备技术领域,具体涉及一种选择性提取锂的钛基离子筛及制备方法和应用。采用固相合成技术制备出钛基锂离子筛(Ti-TO),再用过硫酸钠(Na<Sub>2</Sub>S<Sub>2</Sub>O<Sub>8</Sub>)洗脱后获得对锂离子具有较高的吸附性和选择性的锂离子筛。本发明的技术优点：本发明通过使用细菌纤维素为离子模板,TiO<Sub>2</Sub>作为骨架结构合成的离子筛,选择性好,可在复杂水体中选择性吸附锂离子；吸附量大,在已知的选择性材料中为性能较佳材料；再生性好,本发明中的材料循环再生多次,吸附量没有明显衰减且能够保持优良的选择性,避免了传统锰基锂离子筛由于Mn<Sup>2+</Sup>在洗脱过程中的出现导致了部分结构骨架的溶解。(The invention belongs to the technical field of preparation of environmental materials, and particularly relates to a titanium-based ionic sieve for selectively extracting lithium, and a preparation method and application thereof. Preparing Ti-based lithium ion sieve (Ti-TO) by solid phase synthesis technology, and then using sodium persulfate (Na) 2 S 2 O 8 ) After elution, the lithium ion sieve with high adsorptivity and selectivity to lithium ions is obtained. The invention has the technical advantages that: the invention uses the bacterial cellulose as an ion template and TiO 2 The ion sieve synthesized by the framework structure has good selectivity, and can selectively adsorb lithium ions in a complex water body; the adsorption capacity is large, and the material is a material with better performance in the known selective materials; good reproducibility, the material of the inventionThe ring regeneration is repeated for many times, the adsorption capacity is not obviously attenuated, the excellent selectivity can be kept, and the problem that the traditional manganese-based lithium ion sieve has Mn 2+ The occurrence during elution leads to the dissolution of part of the structural skeleton.)

1. A preparation method of a titanium-based ionic sieve for selectively extracting lithium is characterized by comprising the following steps:

(1) purifying the Bacterial Cellulose (BC) hydrogel in a sodium hydroxide (NaOH) aqueous solution at 90 ℃ for 2h, then washing with deionized water until the pH value reaches neutral, prefreezing with liquid nitrogen, and freeze-drying to obtain the Bacterial Cellulose (BC) aerogel with a layered structure;

(2) soaking the Bacterial Cellulose (BC) aerogel obtained in the step (1) in tetraethyl titanate (TEOT) solution, washing the soaked Bacterial Cellulose (BC) aerogel for 2-6 times by using absolute ethyl alcohol, soaking the soaked Bacterial Cellulose (BC) aerogel in deionized water, mechanically stirring the soaked Bacterial Cellulose (BC) aerogel at room temperature, taking the soaked Bacterial Cellulose (BC) aerogel out, repeatedly washing the obtained product for 2-6 times by using the deionized water and the ethanol, and finally drying the product in a drying oven at the temperature of 90 ℃ to obtain faint yellow TiO₂Wrapped bacterial cellulose film material TiO₂@BC；

(3) TiO obtained in the step (2)₂Putting the @ BC film into a conical flask, adding LiCl solution to form a mixture with different molar ratios, sealing, oscillating for 12 hours in a constant-temperature water bath under 100 strokes, taking out the film, and drying for later use;

(4) putting the film obtained in the step (3) into a tube furnace, calcining the film at a high temperature for 5 hours TO obtain a lithium ion sieve precursor (Ti-TO), and using sodium persulfate (Na) for the calcined lithium ion sieve₂S₂O₈) After elution, a titanium-based lithium ion sieve (Na-TO) with high adsorption and selectivity TO lithium ions is obtained.

2. The method for preparing the titanium-based ionic sieve for selectively extracting lithium according to claim 1, wherein the concentration of the aqueous solution of sodium hydroxide in the step (1) is 0.5-1.5 mol L^-1。

3. The method for preparing the titanium-based ionic sieve for selectively extracting lithium according to claim 1, wherein the mass-to-volume ratio of the bacterial cellulose aerogel to the tetraethyl titanate solution in the step (2) is as follows: 0.08: 30-40, and the soaking time is 2 hours; after washing the mechanical stirring time was 2h at room temperature.

4. The method for preparing the titanium-based ionic sieve for selectively extracting lithium according to claim 1, wherein the concentration of the LiCl solution in the step (3) is 15-25 mmol-L^-1。

5. The method for preparing the titanium-based ionic sieve for selectively extracting lithium according to claim 1, wherein the temperature of the water bath oscillation in the step (3) is 20-30 ℃.

6. The method for preparing the titanium-based ionic sieve for selectively extracting lithium according to claim 1, wherein the calcining temperature of the tube furnace in the step (4) is 400-800 ℃.

7. The method for preparing a titanium-based ionic sieve for selective extraction of lithium as claimed in claim 1, wherein the sodium persulfate (Na) in the step (4)₂S₂O₈) The concentration of the solution is 0.6-1.2 mol/L.

8. A titanium-based ionic sieve prepared according to the method of claim 1, wherein the ionic sieve is a microtubular lithium ionic sieve.

9. The use of the titanium-based ionic sieve prepared by the method of claim 1, wherein the prepared titanium-based lithium ionic sieve is applied to selective recognition and extraction of lithium ions in salt lake brine and seawater.

Technical Field

The invention relates to a titanium-based lithium ion sieve for selectively extracting lithium, a preparation method and application thereof, in particular to a method for preparing the titanium-based lithium ion sieve by taking bacterial cellulose as a template and lithium ions for extracting salt lake brine and seawater, belonging to the technical field of preparation of environmental materials.

Background

Lithium and its compounds are widely used in glass, ceramics, grease, batteries, refrigerants, chemical reagents and other industries, and have important significance for the development of national economy. Most of the lithium is preserved in the salt lake brine, and the rest is mainly lithium-containing ore. In recent years, more and more researchers have come to focus on lithium in seawater. The method for extracting lithium from brine comprises the following steps: precipitation, solvent extraction, selective membrane separation, adsorption, ion exchange, and the like. Among them, adsorption and ion exchange methods are receiving more and more attention due to their high selectivity and good recycling of target ions, and are being applied more and more particularly to low-grade brine and brine.

Common lithium ion sieves include manganese-based lithium ion sieves (Mn-LIS), titanium-based lithium ion sieves (Ti-LIS) and their derivative types. Among them, Mn-LIS was noted earlier than others. A great deal of research is carried out on the synthesis, characterization and application of Mn-LIS, and the advantages of high selectivity, good lithium absorption capacity, recyclability and the like of lithium are realized. However, due to Mn during elution²⁺The occurrence of (b) leads to dissolution of part of the structural framework, and thus concerns about long-term recovery of Mn-LIS have increased. Ti-LIS and derivatives of the type are increasingly emerging to overcome the above deficiencies. Compared with a manganese-based lithium ion sieve, the titanium-based lithium ion sieve has the advantages of lower loss of skeleton elements, good periodicity, more stable structure and the like. However, it is still unavoidable that the lithium ion sieve is made into powder type like the manganese ion sieve, which is not favorable for column operation and industrial production.

The reaction is carried out with hydrochloric acid, nitric acid, sulfuric acid,the lithium ion sieve can be obtained by using eluent such as peroxosulfuric acid and the like. With HCl, HNO₃And H₂SO₄The concentration is increased, the extraction rate of lithium and the loss of manganese and titanium are increased, and the extraction rate of lithium and the loss of manganese and titanium are increased when the adsorbed precursor or product is eluted. That is, with the eluent (HCl, HNO)₃And H₂SO₄) The structure of the adsorbent is more easily destroyed by the increase of the concentration.

Disclosure of Invention

The invention discloses a microtubular lithium ion sieve which is prepared by taking bacterial cellulose as a template and calcining solid-phase conversion, and is applied to extracting lithium ions in salt lake brine and seawater. The ion sieve has high adsorptivity and selectivity for lithium ions, and achieves the purpose of extracting the lithium ions from salt lake brine and seawater.

The technical scheme of the invention is as follows:

a preparation method of a titanium-based lithium ion sieve with specific recognition on lithium ions comprises the following steps:

(1) bacterial Cellulose (BC) hydrogel was purified in aqueous sodium hydroxide (NaOH) at 90 deg.C for 2h to remove bacteria and residual reactions from the film, and then rinsed with deionized water until the pH reached neutral. And (3) obtaining the Bacterial Cellulose (BC) aerogel with a layered structure by liquid nitrogen prefreezing and freeze-drying processes.

Wherein the concentration of the sodium hydroxide (NaOH) aqueous solution is 0.5-1.5 mol L^-1。

(2) Soaking the Bacterial Cellulose (BC) aerogel obtained in the step (1) in a tetraethyl titanate (TEOT) solution for several hours. Then washed 2-6 times with absolute ethanol and immersed in deionized water, and then mechanically stirred at room temperature for several hours and then taken out. Repeatedly cleaning the obtained product with deionized water and ethanol for 2-6 times, and finally drying in an oven to obtain TiO₂Wrapped bacterial cellulose film material TiO₂@BC。

And (3) soaking 0.08g of bacterial cellulose aerogel in 30-40 ml of tetraethyl titanate solution for 2 hours in the step (2), and mechanically stirring for 2 hours at room temperature after washing.

(3) TiO obtained in the step (2)₂The @ BC film is placed in an erlenmeyer flask, LiCl solution is added to form mixtures with different molar ratios, the mixture is sealed and oscillated for 12 hours under a constant temperature water bath under 100 strokes, and the film is taken out and dried for later use.

Wherein the concentration of the LiCl solution in the step (3) is 15-25 mmol.L^-1(ii) a The temperature of the water bath oscillation is 20-30 ℃.

(4) Putting the film obtained in the step (3) into a tube furnace, calcining the film at a high temperature for 5 hours TO obtain a lithium ion sieve precursor (Ti-TO), and using sodium persulfate (Na) for the calcined lithium ion sieve₂S₂O₈) After elution, a titanium-based lithium ion sieve (Na-TO) with high adsorption and selectivity TO lithium ions is obtained.

Wherein the calcining temperature of the tubular furnace in the step (4) is 400-800 ℃; the sodium persulfate (Na)₂S₂O₈) The concentration of the solution is 0.6-1.2 mol/L.

The prepared titanium-based lithium ion sieve is applied to selective recognition and extraction of lithium ions in salt lake brine and seawater.

The invention has the technical advantages that:

(1) the invention uses the bacterial cellulose as an ion template and TiO₂The ion sieve with a support structure and a connected hierarchical pore structure is synthesized as a framework structure, has good selectivity, and can selectively adsorb lithium ions in a complex water body. The defects that most of the existing lithium ion sieves are powder particles, are easy to agglomerate into blocks in the process of absorbing and extracting lithium, and have poor permeability and flowability and the like are overcome.

(2) The adsorption capacity is large, and the material is a material with better performance in the known selective materials.

(3) The material has good reproducibility, the material in the invention can be regenerated for many times in a circulating way, the adsorption capacity is not obviously attenuated, the excellent selectivity can be kept, and the problem that the traditional manganese-based lithium ion sieve has Mn due to Mn is avoided²⁺The occurrence during elution leads to the dissolution of part of the structural skeleton.

Drawings

FIG. 1: TiO 2₂@ BC scanning electron micrograph.

FIG. 2: adsorption kinetics curve.

FIG. 3: the histogram is tested for repeatability.

FIG. 4: and (3) comparing the refrigerator with the liquid nitrogen prefreezing diagram, wherein the refrigerator prefreezing is carried out on the left side, and the liquid nitrogen prefreezing is carried out on the right side.

Detailed Description

The present invention will be described in detail with reference to specific examples.