KR102146063B1 - LITHIUM ABSORBENT COMPRISING A COMPOSITE NANOSHEET IMPREGNATED WITH H2TiO3 AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

The present invention is a lithium adsorbent having a plurality of composite nanosheets, wherein the composite nanosheets include a support including a plurality of pores and a lithium ion body dispersed on the support, and the plurality of composite nanosheets comprises a first A configuration that is laminated in the direction is provided.
Since the lithium ion body as described above is composed of a plurality of composite nanosheets, lithium ions can be more quickly recovered from seawater and can be reused repeatedly.

Description

Lithium adsorbent containing H2TiO3 impregnated composite nanosheet and its manufacturing method {LITHIUM ABSORBENT COMPRISING A COMPOSITE NANOSHEET IMPREGNATED WITH H2TiO3 AND METHOD FOR PRODUCING THE SAME}

The present invention relates to a lithium adsorbent including a plurality of composite nanosheets impregnated with H ₂ TiO ₃ to adsorb lithium ions from brine, and a method for producing the same.

Lithium is widely used for energy-related applications because of its unique and electrochemical properties. The global market for lithium used in batteries is expected to reach 66% by 2025, with an annual growth of more than 4%. In particular, low-resource countries that rely on lithium extracted from brine are facing a crisis in lithium supply.

In general, about 80% or more of lithium is obtained from the soda-lime evaporation method/precipitation of brine, but considering that the work is very laborious and it takes a long time to recover lithium, it is difficult to satisfy the demanded amount of lithium. Seems to be. As another method, lithium ion adsorption and ion exchange using a lithium ion body based on lithium manganese oxide (LMO) such as Li _1.6 Mn _1.6 O ₄ , Li _1.33 Mn _1.67 O ₄ and LiMn ₂ O ₄ Lithium is also obtained in such a way. Recently, lithium ion bodies (LIS) containing titanates such as Li ₄ Ti ₅ O ₁₂ and Li ₂ TiO ₃ (LTO) are attracting more attention because of their excellent chemical stability and excellent adsorption capacity in an acidic environment. However, the LTO powder must be post-treated in a recoverable composition, and it is difficult to apply practically because it is used by mixing with other components having fixed and separating properties on a solid support.

In order to compensate for this problem, research is being actively conducted to make it easier to use by developing a support for fixing the LTO powder. For example, using various polymer materials such as ceramic and polyvinyl alcohol, polyvinyl chloride, polyvinylidene fluoride, polysulfone, and polyacrylonitrile as a binder of LTO powder, a composite lithium adsorbent is prepared in various forms such as a membrane and a foaming agent. Although a method of manufacturing has been proposed, in order to optimize the adsorbents more efficiently, continuous research on a method that can minimize the generation of secondary wastewater in the manufacturing process and improve the adsorption capacity is required.

Korean Patent Registration No. 10-1691089

An object of the present invention is to provide a lithium adsorbent capable of selectively adsorbing lithium ions from brine and a method for producing the same.

The object of the present invention is not limited to the object mentioned above. The object of the present invention will become more apparent from the following description, and will be realized by the means described in the claims and combinations thereof.

The lithium adsorbent according to an embodiment of the present invention is a lithium adsorbent having a plurality of composite nanosheets, wherein the composite nanosheet comprises a support including a plurality of pores and a lithium ion body dispersed on the support, the A plurality of composite nanosheets are laminated and formed in the first direction.

The support is made of polyacrylonitrile (PAN), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polysulfone (PSf), and combinations thereof. It may be at least one selected from the group.

The lithium ion body may be H ₂ TiO ₃ .

The plurality of composite nanosheets may be 5 to 15.

A method of manufacturing a lithium adsorbent according to another embodiment of the present invention includes the steps of (a) mixing and pulverizing a titanium precursor and a lithium precursor to prepare a mixed powder, (b) mixing and stirring a binder and a solvent to prepare a mixed solution. Step, (c) adding and stirring the mixed powder prepared in step (a) to the mixed solution prepared in step (b), followed by electrospinning to obtain composite nanofibers, (d) the (c) Drying and heat treatment of the composite nanofibers obtained in step (e) After immersing the composite nanofibers dried and heat-treated in step (d) in an acid solution, the acid solution remaining on the surface of the composite nanofibers is removed. And drying and (f) laminating at least one or more composite nanofibers having the acid solution removed and dried in step (e) and heat treatment.

In the step (a), the titanium precursor and the lithium precursor may be mixed in a molar ratio of 1: 0.1 to 5.

In step (b), the binder and the solvent are mixed in a weight ratio of 1:1 to 6, and the mixing and stirring may be carried out at a temperature of 20 to 80° C. for 6 to 12 hours.

The binder is made of polyacrylonitrile (PAN), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polysulfone (PSf), and combinations thereof. It may be at least one selected from the group.

The solvent may be at least one selected from the group consisting of dimethylformamide (DMF), tetrahydrofuran (THF), dimethylacetamide (DMAC), acetone, and combinations thereof.

In the step (c), the mixed powder may be added in an amount of 80 to 120 parts by weight based on 100 parts by weight of the mixed solution.

In step (c), electrospinning may be performed under a voltage condition of 10 to 30 kV.

In the step (d), drying may be performed at a temperature of 40 to 80°C for 10 to 20 hours, and heat treatment may be performed at a temperature of 70 to 200°C for 30 minutes to 3 hours.

The heat treatment may be performed for 1 to 2 hours at a temperature of 80 to 100°C.

In the step (e), lithium ions may be desorbed from the composite nanofibers by immersing the composite nanofibers in an acid solution for 22 to 26 hours at a temperature of 20 to 40°C.

The acid solution may be at least one selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, and combinations thereof.

In step (e), the acid solution may be removed using distilled water, and drying may be performed at a temperature of 20 to 40° C. for 10 to 14 hours.

The heat treatment in step (f) may be performed for 1 to 2 hours at a temperature of 80 to 100°C.

A method of manufacturing a lithium adsorbent according to another embodiment of the present invention includes the steps of (a-1) mixing and pulverizing a titanium precursor and a lithium precursor at a molar ratio of 1:0.1 to 5 to prepare a mixed powder, (b-1) Mixing and stirring a binder and a solvent to prepare a mixed solution, (c-1) the mixed powder prepared in step (a-1) with respect to 100 parts by weight of the mixed solution prepared in step (b-1) Adding and stirring 80 to 120 parts by weight and then electrospinning to obtain composite nanofibers, (d-1) drying and heat treating the composite nanofibers obtained in step (c-1), (e-1) ) Step of removing and drying the acid solution remaining on the surface of the composite nanofiber after immersing the composite nanofibers dried and heat-treated in step (d-1) in an acid solution, and (f-1) the (e- It includes the step of heat treatment by laminating at least one or more composite nanofibers that have been removed and dried in step 1).

A method of preparing a lithium adsorbent according to another embodiment of the present invention includes the steps of (a-2) mixing and pulverizing a titanium precursor and a lithium precursor at a molar ratio of 1: 0.1 to 5 to prepare a mixed powder, (b-2) Mixing and stirring polyacrylonitrile (PAN) and dimethylformamide (DMF) at a weight ratio of 1:1 to 6 to prepare a mixed solution, (c-2) the (b-2) Adding and stirring 80 to 120 parts by weight of the mixed powder prepared in step (a-1) to 100 parts by weight of the mixed solution prepared in step, and then electrospinning at a voltage of 10 to 30 kV to obtain composite nanofibers , (d-2) drying and heat treatment of the composite nanofibers obtained in step (c-2), (e-2) the composite nanofibers dried and heat-treated in step (d-2) are mixed with hydrochloric acid ( HCl), removing and drying hydrochloric acid remaining on the surface of the composite nanofibers, and (f-2) at least one composite nanofibers that have been removed and dried in the acid solution in step (e-2). It includes the step of laminating and heat-treating for 1 to 2 hours at a temperature of 80 to 100 ℃.

The lithium ion recovery method according to another embodiment of the present invention includes the steps of adsorbing lithium ions by permeating seawater through a lithium adsorbent, removing seawater remaining on the surface of the lithium adsorbent using distilled water, and removing the lithium adsorbent. It includes the step of immersion in an acid solution to desorb lithium ions.

The lithium adsorbent of the present invention and its manufacturing method are advantageous in that the lithium adsorbent is composed of a plurality of composite nanosheets, so that lithium ions can be more quickly recovered from seawater and can be reused repeatedly.

40mg, S/L ratio = 0.32).
도 10은 표면 접촉각 및 LiCl 용액을 이용한 HTO 복합나노섬우의 습윤성 시험 결과를 나타낸 도이다.
도 11은 서로 상이한 복합나노섬유의 qe값 및 % q 손실값을 나타낸 도이다(C _o = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

40mg, T = 30℃).
도 12는 Co = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

40mg 및 T = 30℃에서 (a) HTO 및 (b) HTO 복합나노섬유의 Li⁺ 흡착의 시간 프로파일을 나타낸 도이다.
도 13은 HTO 분말 및 HTO/PAN 복합나노섬유에 의한 Li⁺ 흡착의 (a) Langmuir and (b) Freundlich plots을 나타낸 도이다(pH

11, S/L ratio = 0.48g/L, m

40mg, 및 T = 30℃).
도 14은 온도에 따른 HTO/PAN 복합나노섬유의 Li⁺ 흡착 효율을 나타낸 도이다(Co = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

40mg)
도 15는 (a) 금속이온(Mⁿ⁺) 흡수, (b) KD of Li+, 및 (c) 다양한 Li⁺:Na⁺:Mg²⁺ 몰비를 가지는 공급원료에 대한 HTO/PAN 복합나노섬유의 Li⁺ 선택도(pH

7, S/L ratio = 0.48g/L, m

40mg, T = 30℃).
도 16은 HTO/PAN 복합나노섬유의 Li+ 흡착에 대한 흡탈착 사이클 성능을 나타낸 도이다(Co = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

4mg, T = 30℃).
도 17은 리튬흡착제의 리튬이온 흡착 성능을 나타낸 도이다(Cf = 11mg/L; F = 300mL/h; Z = 88.78μm(single); A = 28.7cm²; feed pH = 8.05).
도 18은 리튬흡착제의 탈착 성능을 나타낸 도이다(F = 400mL/h, 1.0L 0.50M HCl).1 is a schematic diagram of the HTO composite nanofiber of the present invention.
2 is a diagram showing the result of morphological analysis of Li ₂ TiO ₃ and H ₂ TiO ₃ ((a) XRD, (b) BET surface area, (c) FE-SEM photograph and (d) particle size distribution (PSD) )
Figure 3 is a graph showing the delithium efficiency of HTO composite nanofibers (0.2M HCl, S/L ratio = 1g/L, 24h, 30°C).
4 is a diagram showing the EDS mapping of (a)-(d) FE-SEM photographs, (e)-(h) fiber diameter histograms, and (i)-(l) HTO composite nanofibers
5 is a diagram showing a nitrogen adsorption and desorption isotherm ((a) HTO/PVC (b) HTO/PVDF (c) HTO/PSf (d) HTO/PAN).
6 is a diagram showing the physical and thermal properties of HTO composite nanofibers ((a) mechanical strength, (b) thermogravimetric measurement)
7 is a comparative graph showing the equilibrium pH response (Co = 70mg/L, m ≒ 40m) for experimental qe and Li ⁺ adsorption predicted from HTO composite nanofibers (from RSM model) ((a) HTO/ PVC (b) HTO/PVDF (c) HTO/PSf (d) HTO/PAN)
8 is a diagram showing the S/L ratio for the equilibrium p(a, c, e, g) and qe(b, d, f, h) reaction of Li ⁺ adsorption reaction using HTO composite nanofibers ((a , b) HTO/PVC, (c, d) HTO/PVDF, (e, f) HTO/PSf, (g, h) HTO/PAN).
9 is a diagram showing the range of qe (a) and equilibrium pH (b) values during Li ⁺ adsorption in the initial pH range of different HTO composite nanofibers (Co = /L, m

40mg, S/L ratio = 0.32).
10 is a diagram showing the results of a wettability test of HTO composite nanosums using a surface contact angle and a LiCl solution.
11 is a diagram showing the qe value and% q loss value of different composite nanofibers ( C _o = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

40 mg, T = 30°C).
Figure 12 is Co = 70mg / L, pH

11, S/L ratio = 0.48g/L, m

A diagram showing the time profile of Li ⁺ adsorption of (a) HTO and (b) HTO composite nanofibers at 40mg and T = 30°C.
13 is a diagram showing (a) Langmuir and (b) Freundlich plots of Li ⁺ adsorption by HTO powder and HTO/PAN composite nanofibers (pH

11, S/L ratio = 0.48g/L, m

40 mg, and T = 30°C).
14 is a diagram showing the Li ⁺ adsorption efficiency of HTO/PAN composite nanofibers according to temperature (Co = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

40mg)
Figure 15 shows (a) metal ion (M ⁿ⁺ ) absorption, (b) KD of Li+, and (c) Li of HTO/PAN composite nanofibers for feedstocks having various Li ⁺ :Na ⁺ :Mg ²⁺ molar ratios ⁺ Selectivity (pH

7, S/L ratio = 0.48g/L, m

40 mg, T = 30°C).
16 is a diagram showing the adsorption and desorption cycle performance for Li+ adsorption of HTO/PAN composite nanofibers (Co = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

4 mg, T = 30°C).
17 is a diagram showing the lithium ion adsorption performance of the lithium adsorbent (Cf = 11mg/L; F = 300mL/h; Z = 88.78μm (single); A = 28.7cm ² ; feed pH = 8.05).
18 is a diagram showing the desorption performance of a lithium adsorbent (F = 400 mL/h, 1.0L 0.50M HCl).

The above objects, other objects, features, and advantages of the present invention will be easily understood through the following preferred embodiments related to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed contents may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

The present invention relates to a lithium adsorbent including a polymer composite nanofiber that adsorbs lithium ions and a method for producing the same.

Hereinafter, the lithium adsorbent of the present invention will be described in detail.

1 is a schematic diagram of the HTO composite nanofiber of the present invention.

The lithium adsorbent of the present invention includes a plurality of composite nanosheets, wherein the composite nanosheets include a support including a plurality of pores and a lithium ion body dispersed or adsorbed on the support and fixed.

The support is a group consisting of polyacrylonitrile (PAN), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polysulfone (PSf), and combinations thereof At least one selected from, preferably polyacrylonitrile (PAN) may be, and the lithium ion body may be H ₂ TiO ₃ .

The lithium adsorbent of the present invention includes a plurality of composite nanosheets, and the plurality of composite nanosheets may be stacked in a first direction perpendicular to the ground and integrated by heat. In more detail, the lithium adsorbent includes a first composite nanosheet and a second to nth composite nanosheet laminated on the first composite nanosheet, and the first to nth composite nanosheets each have different pore sizes. It may include a support. In particular, the pores of the support of the first and nth composite nanosheets located at the outermost shells of the lithium adsorbent may be formed larger than the pores of the support of the second to n-1th composite nanosheets, and thus the flow of seawater is more It could be smoother. The n may be 9 to 11, the thickness of the lithium adsorbent may be 880 to 890 μm, and the mass may be 1 to 2 g.

Hereinafter, a method of manufacturing the lithium adsorbent of the present invention will be described in detail.

Referring to FIG. 1, first, a titanium precursor and a lithium precursor are mixed and pulverized to prepare a mixed powder.

The titanium precursor and the lithium precursor were synthesized in a molar ratio of 1: 0.1 to 5, preferably 1:1 to 3, and pulverized with a mortar and pestle for 20 to 40 minutes to be powdered. In this case, the titanium precursor may be TiO ₂ , and the lithium precursor may be Li ₂ CO ₃ .

Then, the binder and the solvent are mixed and stirred to prepare a mixed solution.

After mixing the binder and the solvent in a weight ratio of 1:1 to 6, mixing and stirring may be performed at a temperature of 20 to 80°C for 6 to 12 hours.

The binder is a group consisting of polyacrylonitrile (PAN), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polysulfone (PSf), and combinations thereof. It may be at least one selected from, preferably riacrylonitrile (PAN).

The solvent is at least one selected from the group consisting of dimethylformamide (DMF), tetrahydrofuran (THF), dimethylacetamide (DMAC), acetone, and combinations thereof, preferably It may be dimethylformamide (DMF).

Then, the mixed powder is added to the prepared mixed solution and stirred, and then electrospinned to obtain a composite nanofiber.

The mixed powder may be subjected to electrospinning under a voltage condition of 10 to 30 kV after adding and stirring 80 to 120 parts by weight based on 100 parts by weight of the mixed solution.

Then, the obtained composite nanofibers are dried and heat treated.

After drying the composite nanofibers at a temperature of 40 to 80°C for 10 to 20 hours, heat treatment is performed at a temperature of 70 to 200°C for 30 minutes to 3 hours, preferably at a temperature of 80 to 100°C for 1 to 2 hours can do. If the drying temperature is less than 40°C, it takes a long time for the solvent to dry, so work efficiency may be low, and if it exceeds 80°C, it may affect physical properties, which is not preferable. If the heat treatment temperature is less than 70°C, the heat treatment efficiency may be low, and if it exceeds 200°C, the structural performance such as tensile strength and elongation of composite nanofibers decreases by exceeding 95°C, which is the Tg (glass transition temperature) of PAN. Can be.

Then, the composite nanofibers, which have been dried and heat treated above, are immersed in an acid solution, and the acid solution remaining on the surface of the composite nanofibers is removed and dried.

After immersing the composite nanofiber in an acid solution at a temperature of 20 to 40°C for 22 to 26 hours, the acid solution remaining on the surface of the composite nanofiber can be removed using distilled water. Then, on the surface of the composite nanofiber The remaining distilled water can be removed by drying for 10 to 14 hours at a temperature of 20 to 40°C.

Lithium ions are desorbed from the composite nanofibers by immersing the composite nanofibers in an acid solution, and hydrogen ions are adsorbed thereto, thereby producing H ₂ TiO _{3. In} this case, the acid solution is sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid. And it may be at least one selected from the group consisting of a combination thereof, preferably hydrochloric acid.

Finally, at least one or more composite nanofibers from which the acid solution has been removed and dried are laminated and heat treated.

After the composite nanofibers are sequentially laminated in the first direction, heat treatment may be performed at a temperature of 80 to 100°C for 1 to 2 hours. If the temperature of the heat treatment is less than 80°C, the adhesion between composite nanofibers may be weak, and if it exceeds 100°C, physical properties may be adversely affected.

The present invention comprises the steps of adsorbing lithium ions by permeating seawater through a lithium adsorbent, removing seawater remaining on the surface of the lithium adsorbent using distilled water, and immersing the lithium adsorbent in an acid solution to desorb lithium ions. Lithium ions can be recovered by sequentially performing.

Reference Example 1. Material preparation

Lithium carbonate (≥98.0% Li ₂ CO ₃ ) and titanium oxide powder (99.8% anatase TiO ₂ ) were supplied from Fluka (USA) and Aldrich (USA), respectively, and used as precursors for LTO synthesis, and PAN (MW= 150,000g/mole), PVC (MW=62,000g/mole), and PSf (MW=32,500g/mole) were purchased from Sigma-Aldrich (Mo., USA), and PVDF (Solef 6010) was purchased from Solvay® (Korea ) And used as a polymeric binder. In addition, DMF (>99.5%) was purchased from Junsei Chemical Co., Ltd. (Japan), and THF (>99.8% Tetrahydrofuran, THF) and acetone were provided from Daejung (Korea), and DMAC (99.8% Dimethyl acetamide). Was supplied from Aldrich (USA) and used as a solvent. In addition, hydrochloric acid (RHM 35-37% HCl) and nitric acid (RHM 60% HNO ₃ ) were purchased from Junsei Chemical Co., Ltd. (Japan) and used as a pretreatment solution for LTO elemental analysis, and lithium hydroxide (≥98). % LiOH) and lithium chloride (≥98% LiCl) were purchased from Sigma-Aldrich (Mo., USA) and Fluka (Germany), respectively, and used to prepare a lithium ion solution. All materials were used in the experiment without further purification.

Reference Example 2. Adsorption test method

All adsorption experiments were conducted at 30°C (303K) unless otherwise specified. The initial Li ⁺ concentration and capacity (V) of HTO composite nanofibers were measured. Thereafter, the HTO composite nanofibers were immersed and stirred (150rpm) in Li ⁺ solution for 24 hours in an incubator. Then, the pH and the equilibrium Li ⁺ concentration were measured. The adsorption capacity value ( q _e ) was calculated by equation (1), where C _o and C _e are the initial and equilibrium Li ⁺ concentrations, respectively, V is the solution volume, and m is the HTO dispersed in the composite nanofiber. Mass is

...................................식(1)

Equation (1)

Adsorption at various initial pH was carried out in 10 mM LiOH solution. The pH was lowered with 1M HCl or raised with ammonium hydroxide (28% NH ₃ inH ₂ O). Adsorption kinetics measured the amount of lithium ion adsorption (qt) at different adsorption times (t) before reaching equilibrium (Equation (2)). Adsorption isotherm experiments were performed at C _o = 0.7~7000mg Li ⁺ L ^-1 , and thermodynamics were performed at C _o = 70mg Li ⁺ L ^-1 , 30~60℃.

.................................식(2)

Equation (2)

The selective adsorption performance of lithium ions of the nanocomposite fiber was performed in a mixed solution containing Na ⁺ and Mg ²⁺ in addition to Li ⁺ . In the mixed solution, the molar ratio of Li ⁺ /Na ⁺ /Mg ²⁺ was 1:1:1, 1:100:10, 1:1000:100, and 1:10,000:1000. Li ⁺ selectivity satisfies the following equations (3) and (4) in terms of the partition coefficient ( K _D ) and the separation factor ( α ), and the separation factor ( α ) is of Li ⁺ and Na ⁺ or Mg ²⁺ It was calculated from the distribution coefficient ( K _D ) ratio.

...............................식(3)

...............................Equation (3)

..............................식(4)

..............................Equation (4)

3. Analysis method

The collected liquid sample was filtered with a filter (0.2 mm Nylon syringe filters), and then the pH was measured using a SI analytical pH probe (N5900A) in a TitroLine 7000 titrator (SI Analytics GmbH, Germany). A part of the filtered sample (2 mL) was taken, acid decomposed (3 mL of 60% HNO3) in microwave (MARS-5 CEM, USA), diluted with distilled water (DI) in a polypropylene volumetric flask (100 mL), and filtered. I did. Then, elemental (Li ⁺ , Na ⁺ ,Mg ²⁺ ) analysis was performed using ICP-MS (Agilent 7500 series, USA).

Example 1. HTO preparation

Li ₂ CO ₃ and TiO ₂ (2: 1 Li/Ti molar ratio) was mixed and pulverized for 30 minutes using a mortar and bowl, and then the mixed LTO powder was heat-treated in an air atmosphere (6℃min ^-1 , 700℃) for 4 hours. I did. Then, the LTO powder was cooled at room temperature, pulverized, and separated with a sieve (No. 200, Æ = 63mm) to obtain a uniform particle size (200°C, 63°C). Then, LTO (2g) was dispersed in 0.20M HCl (2L) at 30° C. for 24 hours, followed by Li ⁺ /H ⁺ delithiation treatment according to an ion exchange mechanism. And after pickling, the final LIS (H ₂ TiO ₃ or HTO) was washed with distilled water (DI, deionized water) until the pH became neutral, and dried in an oven at 30° C. for 12 hours to prepare an HTO adsorbent.

Example 2. Preparation of HTO composite nanofiber

PAN, PSf, PVDF, and PVC were each mixed with a solvent under the conditions shown in Table 1 to prepare a mixed solution. LTO powder was added to each of the mixed solutions in an amount of 100% by weight based on the total of the mixed solution, stirred, and then electrospinned to prepare composite nanofibers.

For electrospinning, 12 mL of LTO/mixed solution is put into a plastic syringe equipped with a 21 gauge needle, and a 4-syringe pump (KD Scientific 750, South Korea) in an electrospinning machine (Model: ESP200D/ESP100D, NanoNC Co., Ltd., Korea). It was diluted to ¹ mL/h ^-1 using. A voltage of 15-25 kV was applied between the metal nozzle and the drum-roll collector rotating at a speed of 500 rpm. Each detailed electrospinning condition is as described in Table 2 below.

Table 1 is a table showing the conditions of the mixed solution.

Conditions PAN PSf PVDF PVC Solvent DMF THF:DMF=1:2
(Volume ratio) DMAc:Acetone=1:1
(Volume ratio) THF:DMF=1:2 (volume ratio) Polymer wt. % 10 18 15 15 Mixing 4h at 60°C and 4h at RT, 700rpm 10h at RT, 700rpm 12h at RT, 700rpm 10h at RT, 700rpm *RT= room temperature

Table 2 is a table showing the electrospinning conditions of the LTO/polymer composite material.

Parameters PAN PSf PVDF PVC Syringe pumping speed (mL/h) 4 4 4 4 Voltage (kV) 22-25 23 23 15 Needle size 21GA 21GA 21GA 21GA Distance between needle and collector (mm) 100 120 150 100 Collector speed (rpm) 500 500 500 500 Electrospun amount (mL) 12 12 12 12

In order to remove the excess mixed solvent present in the composite nanofibers, it was dried in an oven at 60°C overnight. Except for the LTO/PVDF composite nanofibers, the remaining composite nanofibers were heat treated for 1.5 hours at 90°C (LTO/PAN), 105°C (LTO/PVC), and 190°C (LTO/PSf), respectively, to improve mechanical strength. Implemented. The heat-treated composite nanofibers were dispersed in 0.20M HCl at 30°C for 24 hours, washed with distilled water until the pH became neutral, and then dried in an oven at 30°C for 12 hours to prepare HTO composite nanofibers.

Experimental Example 1. Confirmation of lithium adsorbent properties

The synthesis of LTO and HTO powder was confirmed using an X-ray diffractometer (40kV, 30mA, 0.03step count ^-1 , Cu Kα source, PAN alytical X'pert-Pro, The Netherlands), and the surface shape was confirmed using an optical microscope ( It was observed with a Field Emission Scanning Electron Microscope (Hitachi SU-70 FESEM-EDX, japan)). And, the nitrogen adsorption/desorption isotherm was measured under a relative pressure range (p/po) of 0.01 to 1.0 using Belsorp-mini II (Bel Japan, Inc.), and the surface area was Brunauer-Emmett-Teller (BET) N2 isotherm. Was quantified from Porosity was estimated using the relationship P = 1-(ρa/ρt) × 100%.

2 is a diagram showing the result of morphological analysis of Li ₂ TiO ₃ and H ₂ TiO ₃ ((a) XRD, (b) BET surface area, (c) FE-SEM photograph and (d) particle size distribution (PSD) )

Referring to FIG. 2, it was confirmed that the peaks between LTO and HTO are similar, but several peaks are shifted, widened, and weakened. This structural change could be predicted from the fact that lithium ions were replaced by hydrogen ions by acid treatment. In addition, although small pores were found in HTO, it was confirmed that the particle size was maintained at dave = 143 nm.

Experimental Example 2. Characteristics of HTO composite nanofiber

Table 3 is a table showing the physicochemical properties of LTO composite nanofibers.

NF type Theoretical q
(mg g ^-1 ) d _ave
(nm) SA _BET
(m ² g ^-1 ) ρ _t
(g cm ^-3 ) ρ _a
(g cm ^-3 ) P
(%) LTO content
(% w/w) LTO/PVC 120.31 173.93 1.8 1.33
± 0.07 0.50
± 0.04 62.4
± 4.83 49.07 LTO/PVDF 120.56 152.22 2.0 1.43
± 0.01 0.76 ± 0.05 50.4
± 0.03 48.71 LTO/PSf 121.91 258.29 1.5 1.36
± 0.03 0.44 ± 0.01 68.5
± 1.86 45.49 LTO/PAN 121.97 178.77 3.9 1.40
± 0.02 0.45 ± 0.01 68.0
± 0.89 46.35

3 is a graph showing the lithiation efficiency of HTO composite nanofibers (0.2M HCl, S/L ratio = 1g/L, 24h, 30°C)

Referring to Table 3 and FIG. 3, it can be seen that the lithiation efficiency of the LTO composite nanofiber is very high, 95.1 to 96.4%, which is similar to pure HTO powder. In addition, it was confirmed that the lithium adsorption efficiency of HTO/PAN and HTO/PSf was 122.0 mg/g or more, which was higher than that of HTO/PVC (120.3 mg/g) and HTO/PVDF (120.6 mg/g).

4 is a diagram showing the EDS mapping of (a)-(d) FE-SEM photographs, (e)-(h) fiber diameter histograms, and (i)-(l) HTO composite nanofibers.

Referring to FIG. 4, it was confirmed that the HTO particles were encapsulated in the fiber together with some aggregates exposed on the fiber surface, and were distributed over the entire fiber.

5 is a diagram showing a nitrogen adsorption and desorption isotherm ((a) HTO/PVC (b) HTO/PVDF (c) HTO/PSf (d) HTO/PAN).

Referring to FIG. 5, HTO composite nanofibers generate very small intermediate pores, and SA _BET of HTO composite nanofibers is <5 m ² /g, and fibers having a diameter of less than 500 nm are common. The actual density of all nanocomposite fibers is similar to that expected, taking into account similar density polymers and the same HTO loading. However, the deformation of a is due to the difference in porosity between the composite nanofibers, and the change in P is due to the different properties of the fibers when different types of nanocomposite fibers are manufactured under different solvent systems and electrospinning conditions.

6 is a diagram showing the physical and thermal properties of HTO composite nanofibers ((a) mechanical strength, (b) thermogravimetric measurement).

Referring to Figure 6a, the mechanical strength is affected by the type of the support used, of which PVC is the weakest, while PAN and PVDF it was confirmed that they have similar tensile strength to each other as 9Nmm ^-2 . It was found that mixing of HTO can reduce the toughness of the composite nanofibers and cause structural collapse in the fibers.

Referring to FIG. 6B, it was confirmed that all polymer components were decomposed at 700°C or higher.

Experimental Example 3. Confirmation of adsorption properties of HTO composite nanosheets

3-1. RSM through CCD access

For each type of HTO composite nanofiber, an experiment based on CCD (Table 4) was performed to obtain a correlation between the independent variables (S/L ratio and initial pH) and the reaction parameter qe and the equilibrium pH.

Run Initial pH ( x ₁ ) S/L ratio ( x ₂ ) One 7.00 0.32 2 9.50 0.94 3 5.96 0.58 4 7.00 0.83 5 9.50 0.58 6 9.50 0.58 7 5.96 0.58 8 12.00 0.32 9 9.50 0.58 10 9.50 0.58 11 9.50 0.21 12 9.50 0.58 13 13.04 0.58 14 7.00 0.83 15 9.50 0.58 16 12.00 0.83 17 13.04 0.58 18 12.00 0.83 19 7.00 0.32 20 9.50 0.21 21 12.00 0.32 22 9.50 0.94

7 is a comparative graph showing the equilibrium pH response (Co = 70mg/L, m ≒ 40m) for experimental qe and Li ⁺ adsorption predicted from HTO composite nanofibers (from RSM model) ((a) HTO/ PVC, (b) HTO/PVDF, (c) HTO/PSf, (d) HTO/PAN)

Referring to FIG. 7, it was found that the predicted results for all qe and equilibrium pH values for all types of HTO composite nanofibers and the experimental results were accurately matched.

NF type Intercept + b _i ´pH + b _j ´ S/L +b _ij ´(pH´ S/L ) +b _ii ´pH ² + b _jj ´ [ S/L ] ² HTO/PVC q _e = 53.075 -7.352 -43.313 1.660 0.496 6.092 Eq. pH = 21.522 -4.221 -3.175 -0.388 0.291 5.245 HTO/PVDF q _e = 62.368 -8.457 -50.921 2.013 0.544 8.228 Eq. pH = 13.803 -2.274 -4.233 -0.039 0.179 2.938 HTO/PSf q _e = 17.956 -0.247 -11.041 2.139 0.131 -30.034 Eq. pH = 14.335 -2.579 -0.988 -0.539 0.209 3.351 HTO/PAN q _e = 27.779 -0.935 -25.339 3.326 0.128 -28.289 Eq. pH = 13.562 -2.365 -2.613 -0.210 0.190 2.762

8 is a diagram showing the S/L ratio for the equilibrium p(a, c, e, g) and qe(b, d, f, h) reaction of Li ⁺ adsorption reaction using HTO composite nanofibers ((a , b) HTO/PVC, (c, d) HTO/PVDF, (e, f) HTO/PSf, (g, h) HTO/PAN).

Referring to FIG. 8, it was confirmed that qe and equilibrium pH of all HTO composite nanofibers were opposite to the initial pH and S/L ratio, and the lowest reaction was performed at the high S/L ratio and the lowest pH. . Therefore, referring to Reaction Formula 1 below, it could be guessed that the qe of all HTO composite nanofibers can be maximized when H ⁺ accumulation is minimized. In addition, it was found that an increase in qe indicates a Li ⁺ adsorption preference.

3-2. HTO screening

40mg, S/L ratio = 0.32).9 is a diagram showing the range of qe (a) and equilibrium pH (b) values during Li ⁺ adsorption in the initial pH range of different HTO composite nanofibers (Co = 70 mg/L, m

40mg, S/L ratio = 0.32).

Referring to FIG. 9, S/L ratio =0.32 was selected to minimize the effect on qe of all NFs. Therefore, it could be confirmed that the difference in the range of the response value was due to the difference in the pH of the support and the feed, and HTO/PAN composite nanofibers (qe = 25.81-36.83mg/g) were more effective than all other composite nanofibers. Could know.

In addition, the contact angle was measured to investigate the surface hydrophilicity of the support.

10 is a diagram showing the results of a wettability test of HTO composite nanofibers using a surface contact angle and a LiCl solution.

As a result, referring to FIG. 10, PAN was the most hydrophilic at 71.74°±1.97, which was also visible with the naked eye while the HTO/PAN composite nanofibers passed through the LiCl solution.

In order to accurately observe the effect of PAN on the adsorption performance of dispersed HTO, q _HTO and q _{HTO composite nanofibers (NF)} were compared. HTO composite nanofibers showed lower values than pure HTO, and the parallel adsorption loss was estimated as %q loss in Equation 5.

...............식(5)

...............Equation (5)

11, S/L ratio = 0.48g/L, m

40mg, T = 30℃)11 is a diagram showing the qe value and% q loss value of different composite nanofibers ( C _o = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

40mg, T = 30℃)

Referring to FIG. 11, all composite nanofibers have a low qe, which may be an influence of the support, and a mismatch in qe may be a %q loss for pure HTO.

Due to the high wettability of HTO/PAN composite nanofibers, it was confirmed that %q loss=7%, as opposed to PVC and PVDF with %q loss=31~37%. Accordingly, it was found that the HTO/PAN composite nanofibers can minimize q loss.

In order to confirm the adsorption characteristics of HTO/PAN composite nanofibers, a comparative experiment was conducted with pure HTO powder. Pure HTO showed no pH inhibition in adsorption performance when the S/L ratio was <0.48 and the initial pH was about 11.

3-3. Li ⁺ Adsorption kinetics

11, S/L ratio = 0.48g/L, m

40mg 및 T = 30℃에서 (a) HTO 및 (b) HTO 복합나노섬유의 Li⁺ 흡착의 시간 프로파일을 나타낸 도이다. Figure 12 is Co = 70mg / L, pH

11, S/L ratio = 0.48g/L, m

A diagram showing the time profile of Li ⁺ adsorption of (a) HTO and (b) HTO composite nanofibers at 40mg and T = 30°C.

Referring to FIG. 12, it was confirmed that qt of HTO powder and HTO/PAN composite nanofibers rapidly increased up to 9 hours, but qt gradually reached a stable value (qe = 31-32 mg/g) from 10 hours or more. . As defined by Equation 16-17, nonlinear regression analysis was performed using pseudo-first and pseudo-second velocity models. k1 and k2 are rate constants.

.............................식(6)

.............................Equation (6)

.....................................식(7)

Equation (7)

Sample Pseudo-first order Pseudo-second order q _e (mg g ^-1 ) k ₁ × 10 ^-3
(min ^-1 ) r ² q _e (mg g ^-1 ) k ₂ × 10 ^-4 (gmg ^-1 min ^-1 ) r ² HTO powder 32.16 4.31 0.989 35.82 1.91 0.993 HTO/PAN NF 31.05 4.11 0.988 34.74 1.89 0.998

11, S/Lratio = 0.48g/L, m

40mg and T = 30℃pH

11, S/L ratio = 0.48g/L, m

40mg and T = 30℃

Referring to Table 6, the qe value of the HTO powder was slightly higher than that of the HTO/PAN composite nanofiber, and the K ₂ difference between the HTO powder and the HTO/PAN composite nanofiber was small in a similar secondary velocity model. It was found that HTO dispersed in PAN had a very small effect on the Li ⁺ adsorption rate. It could be assumed that the hydrophilicity of the support and the nanofiber structure contributes to the Li ⁺ absorption rate in HTO/PAN.

3-4. Li ⁺ Adsorption isotherm

Collect equilibrium adsorption results from various C _o to prove the adsorption mechanism involved by HTO/PAN composite nanofibers, and analyze them using Langmuir and Freundlich models as defined by the following equations (18) and (19). I did. qm is the maximum monolayer Li ⁺ capacity of HTO in HTO/PAN composite nanofibers, K _L is the adsorption energy demand, K _F is the Freundlich constant, and n is the adsorption strength.

...........................식(8)

...........................Equation (8)

.........................식(9)

.........................Equation (9)

11, S/L ratio = 0.48g/L, m

40mg, 및 T = 30℃).13 is a diagram showing (a) Langmuir and (b) Freundlich plots of Li ⁺ adsorption by HTO powder and HTO/PAN composite nanofibers (pH

11, S/L ratio = 0.48g/L, m

40 mg, and T = 30°C).

Sample Langmuir Freundlich q _m
(mg/g) K _L
(L/mg) r ² n K _F
r ² HTO powder 73.43 0.0157 0.99 3.58 12.25 0.68 HTO/PAN NF 72.75 0.0164 0.99 4.01 12.87 0.98

11, S/Lratio = 0.48g/L, m

40mg, T = 30℃pH

11, S/L ratio = 0.48g/L, m

40mg, T = 30℃

13 and Table 7, it was found that the HTO/PAN composite nanofiber has a lower qm than the HTO powder, and the PAN in which HTO is dispersed can minimize the loss. That is, the HTO/PAN composite nanofibers captured Li ^{+ up} to 72.75mg/g, which was confirmed to be one of the highest values reported for the LIS composite.

3-5. Li ⁺ Thermodynamics of adsorption

In order to evaluate the absorption performance of Li ⁺ according to temperature, Gibbs free energy (△ G ^o ), enthalpy (△ H ^o ), and entropy (△ S ^o ) were calculated from the qe value according to Equation (20).

The equilibrium coefficient ( K ^o ) is the product of K _D and the density of _HTO (r _HTO = 2336.10.0kg m ^-3 ). In addition, in equation (21), which is the Van't Hoff equation, ΔH ^o is the standard enthalpy change of the equilibrium reaction, and ΔS ^o is the intercept of the gas constant (R).

.............................식(10)

.............................Equation (10)

...........................식(11)

...........................Eq. (11)

Table 8 is a table showing the thermodynamic parameters of Li ⁺ adsorption in HTO and HTO/PAN composite nanofibers.

T ( ^o C) △ G ^o (kJ mol ^-1 ) △ H ^o (kJ mol ^-1 ) △ S ^o (kJ mol ^-1 K ^-1 ) HTO/PAN NF HTO powder HTO/PAN NF HTO powder HTO/PAN NF HTO powder 30 -18.09 -18.31 6.54 6.09 0.08 0.08 40 -18.86 -19.10 50 -19.72 -19.93 60 -20.51 -20.72

11, S/Lratio = 0.48g/L, m

40mgC _o = 70mg/L, pH

11, S/Lratio = 0.48g/L, m

40mg

11, S/L ratio = 0.48g/L, m

40mg)14 is a diagram showing Li ⁺ adsorption efficiency of HTO/PAN composite nanofibers according to temperature (Co = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

40mg)

Referring to Table 8 and FIG. 14, it was confirmed that -△ G ^o and +△ S ^o represent spontaneous Li ⁺ adsorption, and that decrease of △ G ^o according to an increase in temperature promotes the diffusion of HTO. In addition, +△ S ^o is As Li ⁺ adsorption proceeds, it shows that the HTO/PAN composite nanofibers increase at the solid-liquid interface. Accordingly, it was found that the increase in entropy in the water molecule is greater than that of Li ⁺ . +△ H ^o suggests that the endothermic process proceeds, which It means that the energy consumed in Li ⁺ desorption exceeds the exothermicity of Li ⁺ /H ⁺ ion exchange. Therefore, it was found that HTO/PAN had less loss of q than HTO at various temperatures, and △ G ^o and △ H ^o were higher, indicating that a greater driving force was required for Li ⁺ adsorption.

3-6. Li ⁺ Selectivity

To confirm the ability of HTO composite nanofibers to selectively absorb Li ⁺ in the presence of M ⁿ⁺ =Na ⁺ and Mg ²⁺ , M ⁿ⁺ (1M Na ⁺ and 0.1M Mg ²⁺ ) and Li ⁺ (1 mM) of the isothermal mixture -The experiment was conducted while adjusting the molar ratio of 0.1mM) differently.

7, S/L ratio = 0.48g/L, m

40mg, T = 30℃).Figure 15 shows (a) metal ion (M ⁿ⁺ ) absorption, (b) KD of Li+, and (c) Li of HTO/PAN composite nanofibers for feedstocks having various Li ⁺ :Na ⁺ :Mg ²⁺ molar ratios ⁺ Selectivity (pH

7, S/L ratio = 0.48g/L, m

40 mg, T = 30°C).

Referring to FIG. 15, it was confirmed that in the isothermal mixture composed of different molar ratios, M ⁿ⁺ was hardly adsorbed in contrast to Li ⁺ having qe = 4.52 mmol/g. As the M ⁿ⁺ concentration increased, qe gradually increased to less than 0.11 mmol/g, whereas it was confirmed that qe gradually decreased as the Li ⁺ silver concentration increased. This was not related to M ⁿ⁺ , and it was found that there is a close correlation with low C _o in the mixture. Regardless of the presence or absence of M ⁿ⁺ , if the difference in the qe value of Li ⁺ was small, it could be assumed that the HTO/PAN composite nanofiber has high selectivity for Li ⁺ .

In addition, it was confirmed that the range of the K _D value for Li ⁺ according to the increase of the M ^{n +} concentration for qe was 435 to 3872 mL/g, and the Na ⁺ and Mg ²⁺ values did not exceed 1.2 mL/g. That is, it was found from the KD value that the HTO/PAN composite nanofibers have higher selectivity than Na ⁺ and Mg ²⁺ . In conclusion, it was found that the HTO/PAN composite nanofiber has very good Li ⁺ capture performance in the presence of a high M ^{n +} concentration.

Experimental Example 4. Reusability check

4-1. Confirmation of reusability of HTO composite nanofiber

In order to confirm the reusability of the composite nanosheet, the adsorption/desorption experiment was repeatedly performed as follows.

11, S/L ratio = 0.48, 및 30℃의 조건으로 흡/탈착 실험을 반복적으로 실시하였으며, 매회 흡착공정 후 Li+ 분석을 위해 액체 샘플의 일부를 채취하였다. 그리고, 사용된 복합나노섬유의 표면에 잔존하는 용액은 증류수를 이용하여 세척한 후 0.20M HCl에 침지시켜 30℃에서 24시간 동안 Li⁺ 회수 및 재생하였다. 재생된 복합나노섬유는 pH가 중성이 될 때까지 증류수(DI)로 다시 세척한 다음 진공 건조한 다음 칭량하였다(다음 사이클을 진행하기 이전에 칭량함). C _o = 70mg Li ⁺ L ^-1 , initial pH

11, S/L ratio = 0.48, and the adsorption/desorption experiment was repeatedly performed under the conditions of 30° C., and a part of the liquid sample was taken for Li+ analysis after each adsorption process. In addition, the solution remaining on the surface of the used composite nanofibers was washed with distilled water and then immersed in 0.20M HCl to recover and regenerate Li ⁺ at 30° C. for 24 hours. The regenerated composite nanofibers were washed again with distilled water (DI) until the pH became neutral and then vacuum dried and then weighed (weighed before proceeding with the next cycle).

11, S/L ratio = 0.48g/L, m

4mg, T = 30℃).16 is a diagram showing the adsorption and desorption cycle performance for Li+ adsorption of HTO/PAN composite nanofibers (Co = 70mg/L, pH

11, S/L ratio = 0.48g/L, m

4 mg, T = 30°C).

Referring to FIG. 16, it was confirmed that the qe value did not decrease significantly and remained constant despite repeated adsorption and desorption cycles. Accordingly, it was found that the HTO-applied composite nanofiber of the present invention is structurally excellent in repeated adsorption and desorption cycles, and can be reused as the adsorption and desorption efficiency of lithium ions is maintained.

4-1. Confirmation of reusability of lithium adsorbent

In order to confirm the reusability of the lithium adsorbent containing a plurality of composite nanofibers, the adsorption/desorption experiment was repeatedly performed as follows.

Composite nanofibers were cut to be 36 cm 2 in width and length, respectively, laminated until the thickness became 1.082±0.05mm and weight 132.3±6.8mg, heat treated at 90℃ for 1.5 hours, and cooled to It was cut into a circle and applied as a filter for lithium adsorption for experiments.

17 is a diagram showing the lithium ion adsorption performance of the lithium adsorbent (Cf = 11mg/L; F = 300mL/h; Z = 88.78μm (single); A = 28.7cm ² ; feed pH = 8.05).

18 is a diagram showing the desorption performance of a lithium adsorbent (F = 400 mL/h, 1.0L 0.50M HCl).

As a result, referring to FIGS. 17 and 18, it was confirmed that as time passed, lithium ions gradually reached a saturation state and the adsorption and desorption operation was continuously performed. Accordingly, it was found that the lithium adsorbent of the present invention was freely adsorbed and desorbed in repeated cycles.

Although the invention made by the present inventor has been described in detail according to the above embodiment, the invention is not limited to the above embodiment, and it goes without saying that the invention can be changed in various ways within the scope not departing from the gist.

Claims (20)

As a lithium adsorbent having a plurality of composite nanosheets,
The composite nanosheet is a support including a plurality of pores and
Including a lithium ion body dispersed on the support,
The plurality of composite nanosheets are laminated and formed in a first direction,
The support is polyacrylonitrile (PAN),
The lithium ion body is a lithium adsorbent, characterized in that H ₂ TiO ₃ .
delete delete The method of claim 1,
The plurality of composite nanosheets are 5 to 15 lithium adsorbents.
(a) mixing and pulverizing a titanium precursor and a lithium precursor to prepare a mixed powder;
(b) mixing and stirring a binder and a solvent to prepare a mixed solution;
(c) adding and stirring the mixed powder prepared in step (a) to the mixed solution prepared in step (b), followed by electrospinning to obtain composite nanofibers;
(d) drying and heat treating the composite nanofibers obtained in step (c);
(e) removing and drying the acid solution remaining on the surface of the composite nanofiber after immersing the composite nanofibers dried and heat-treated in step (d) in an acid solution; And
(f) laminating at least one or more composite nanofibers, in which the acid solution has been removed and dried in step (e), and heat-treated,
The binder is polyacrylonitrile (PAN),
The method of manufacturing a lithium adsorbent containing H ₂ TiO ₃ as the composite nanofibers subjected to the step (e).
The method of claim 5,
In the step (a), the titanium precursor and the lithium precursor are mixed in a molar ratio of 1: 0.1-5.
The method of claim 5,
In the step (b), the binder and the solvent are mixed in a weight ratio of 1:1 to 6, and the mixing and stirring are performed at a temperature of 20 to 80°C for 6 to 12 hours.
delete The method of claim 7,
The solvent is at least one lithium adsorbent selected from the group consisting of dimethylformamide (DMF), tetrahydrofuran (THF), dimethylacetamide (DMAC), acetone, and combinations thereof. Manufacturing method.
The method of claim 5,
In the step (c), the mixed powder is 80 to 120 parts by weight based on 100 parts by weight of the mixed solution.
The method of claim 5,
In the step (c), electrospinning is performed under a voltage condition of 10 to 30 kV.
The method of claim 5,
In the step (d), drying is performed at a temperature of 40 to 80°C for 10 to 20 hours, and heat treatment is performed at a temperature of 70 to 200°C for 30 minutes to 3 hours.
The method of claim 12,
The heat treatment is a method of producing a lithium adsorbent performed for 1 to 2 hours at a temperature of 80 to 100 ℃.
The method of claim 5,
In the step (e), the composite nanofiber is immersed in an acid solution at a temperature of 20 to 40°C for 22 to 26 hours to desorb lithium ions from the composite nanofiber.
The method of claim 5,
The acid solution is at least one selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, and combinations thereof.
The method of claim 5,
In step (e), the acid solution is removed using distilled water, and the drying is performed at a temperature of 20 to 40° C. for 10 to 14 hours.
The method of claim 5,
The heat treatment in step (f) is a method of producing a lithium adsorbent performed for 1 to 2 hours at a temperature of 80 to 100°C.
(a-1) preparing a mixed powder by mixing and pulverizing a titanium precursor and a lithium precursor in a molar ratio of 1:0.1-5;
(b-1) preparing a mixed solution by mixing and stirring a binder and a solvent;
(c-1) 80 to 120 parts by weight of the mixed powder prepared in step (a-1) is added to 100 parts by weight of the mixed solution prepared in step (b-1), stirred, and then electrospun Obtaining fibers;
(d-1) drying and heat treating the composite nanofibers obtained in step (c-1);
(e-1) removing and drying the acid solution remaining on the surface of the composite nanofibers after immersing the composite nanofibers dried and heat-treated in step (d-1) in an acid solution; And
(f-1) comprising the step of laminating at least one or more composite nanofibers, in which the acid solution has been removed and dried in step (e-1), and heat treatment,
The binder is polyacrylonitrile (PAN),
The method of manufacturing a lithium adsorbent containing H ₂ TiO ₃ as the composite nanofibers subjected to the step (e-1).
(a-2) preparing a mixed powder by mixing and pulverizing a titanium precursor and a lithium precursor at a molar ratio of 1: 0.1 to 5;
(b-2) preparing a mixed solution by mixing and stirring polyacrylonitrile (PAN) and dimethylformamide (DMF) in a weight ratio of 1:1 to 6;
(c-2) 80 to 120 parts by weight of the mixed powder prepared in step (a-2) are added and stirred with respect to 100 parts by weight of the mixed solution prepared in step (b-2), followed by a voltage of 10 to 30 kV Electrospinning to obtain a composite nanofiber;
(d-2) drying and heat treating the composite nanofibers obtained in step (c-2);
(e-2) removing and drying the hydrochloric acid remaining on the surface of the composite nanofiber after immersing the composite nanofibers dried and heat-treated in step (d-2) in hydrochloric acid (HCl); And
(f-2) laminating at least one or more composite nanofibers, which have been removed and dried in the acid solution in step (e-2), and heat-treated at a temperature of 80 to 100°C for 1 to 2 hours,
The method of manufacturing a lithium adsorbent containing H ₂ TiO ₃ as the composite nanofibers subjected to the step (e-2).
Adsorbing lithium ions by permeating seawater through the lithium adsorbent according to claim 1;
Removing seawater remaining on the surface of the lithium adsorbent using distilled water; And
A lithium ion recovery method comprising the step of immersing the lithium adsorbent in an acid solution to desorb lithium ions.

Images