CN113351180B - Preparation method and application of temperature response type bionic lithium ion imprinting composite membrane - Google Patents

Abstract

A preparation method and application of a temperature response type bionic lithium ion imprinting composite membrane relate to a preparation method and application of a lithium ion imprinting composite membrane. The invention aims to solve the problems that an acidic desorption reagent causes irreversible damage to adsorption sites and generates a large amount of elution wastewater in the preparation and application processes of the conventional bionic lithium ion imprinted composite membrane. The method comprises the following steps: firstly, preparing a PDA @ PVDF film; secondly, preparing a PDA @ PVDF-RAFT film; thirdly, preparing a PDA @ PVDF-RAFT-PDEA film; and fourthly, preparing Li-TSIIM. Temperature response type bionic lithium ion imprinting composite membrane for absorbing Li⁺. The temperature response type bionic lithium ion imprinted composite membrane prepared by the invention has better selective adsorption capacity on lithium ions, and has the characteristics of strong reproducibility and good chemical stability. The temperature response type bionic lithium ion imprinting composite membrane can be obtained.

Description

Preparation method and application of a temperature-responsive biomimetic lithium ion imprinted composite membrane

technical field

The invention relates to a preparation method and application of a lithium ion imprinted composite membrane.

Background technique

As a rechargeable battery that appeared in the 1990s, lithium-ion batteries are widely used in portable devices such as mobile phones, notebook computers, and digital cameras. At the same time, it is gradually popularized in the military, medical and electric vehicle fields. At present, my country has become a major country in the production, consumption and export of lithium-ion batteries.

With the popularity of lithium-ion batteries in various industries, the global demand for lithium has exploded. There are about 25.5 million tons of Li resources in the world. According to the current usage rate, it will be exhausted in about 15 years. Therefore, from the perspective of environmental protection and energy consumption, it is of great significance to recover resources from waste lithium batteries. At present, the commonly used methods for recovering lithium from waste lithium-ion batteries mainly include chemical method and solvent extraction method. However, chemical recovery of lithium is not only complicated in process, but also accompanied by the use of a large number of chemicals, which has a great impact on the environment; while solvent extraction methods mostly use organic solvents as background solvents, which are not only expensive, but also easy to cause fires and have a low safety factor. high. Therefore, there is an urgent need for a new recycling technology that is safe, reliable and simple to selectively recycle Li ⁺ in spent lithium-ion batteries.

As an emerging selective separation and purification technology, biomimetic ion-imprinted membranes are expected to selectively and directly recover Li resources in the leaching solution of complex spent lithium-ion batteries. Compared with the current common methods such as chemical precipitation and solvent extraction, the advantages of biomimetic ion-imprinted membranes lie in high selectivity, good separation effect, and strong reusability, which is suitable for the direct selective recovery of Li resources in waste lithium-ion batteries and It is of great significance to solve the current shortage of Li resources in the world. However, during the preparation and application of biomimetic ion-imprinted membranes, the template ions (Li ⁺ ) must be removed by acid washing, which not only causes irreversible damage to the adsorption sites, but also produces a large amount of elution wastewater. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem of irreversible damage to the adsorption site caused by the acid desorption reagent and the generation of a large amount of elution wastewater during the preparation and application of the existing bionic lithium ion imprinted composite membrane, and to provide a temperature-responsive bionic Preparation method and application of lithium ion imprinted composite membrane.

A preparation method of a temperature-responsive bionic lithium ion imprinted composite membrane is completed according to the following steps:

1. Preparation of PDA@PVDF membrane:

First dissolve tris(hydroxymethyl)aminomethane in deionized water, then adjust the pH to be alkaline, then add dopamine hydrochloride and a piece of PVDF membrane, and finally stir, after stirring, take out the PVDF membrane, rinse the PVDF membrane with deionized water, Drying again to obtain PDA@PVDF membrane;

2. Preparation of PDA@PVDF-RAFT membrane:

4-Dimethylaminopyridine and trithiocarbonate were dissolved in dichloromethane, and then PDA@PVDF membrane was added. Under the protection of nitrogen atmosphere, dicyclohexylcarbodiimide was added, and the reaction system was sealed again. , under the conditions of stirring and ice bath, after the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain the PDA@PVDF-RAFT membrane;

3. Preparation of PDA@PVDF-RAFT-PDEA membrane:

The PDA@PVDF-RAFT membrane was added to the mixture of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane, and nitrogen was passed through, and then the reaction system was sealed. The reaction was carried out under nitrogen atmosphere and stirring conditions. After the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain a PDA@PVDF-RAFT-PDEA membrane;

4. Preparation of Li-TSIIM:

LiCl and 12-crown ether-4 were added to methanol, and then stirred to obtain a mixed solution; the PDA@PVDF-RAFT-PDEA membrane was put into the mixed solution, and azobisisobutyronitrile, ethylene glycol di Methacrylate and methacrylic acid were introduced into nitrogen, and then the reaction system was sealed, condensed and refluxed under nitrogen atmosphere, stirring and temperature of 75 ° C. After the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain Li-TSIIM, It is a temperature-responsive biomimetic lithium-ion imprinted composite membrane.

A temperature-responsive biomimetic lithium-ion imprinted composite membrane is used to adsorb Li ⁺ .

Principle of the present invention:

N,N-diethyl-2-acrylamide (DEA) is a common temperature-sensitive material with a critical temperature of 32 °C. When T<32°C, the polymer PDEA is in an expanding state; when T>32°C, PDEA is in a contracting state (as shown in Figure 1). Therefore, the present invention grafts DEA as a temperature-sensitive functional monomer through the polymerization of reversible addition-fragmentation chain transfer (RAFT) in the process of preparing a temperature-responsive biomimetic lithium-ion imprinted composite membrane to form PDEA, which is then attached to PDEA. The functional monomers 12-crown ether-4 and methacrylic acid, which can specifically recognize Li ⁺ , endow the biomimetic lithium-ion imprinted membrane with temperature-responsive functions. The feature of the present invention is that under the condition of T<32°C, PDEA is in an expanded state, so that the grafted 12-crown-4 and methacrylic acid are kept away from Li ⁺ (as shown in Fig. 1 ) to achieve desorption of Li ⁺ On the contrary, under the condition of T>32℃, PDEA is in a shrinking state, so that the grafted 12-crown-4 and methacrylic acid are close to Li ⁺ to achieve the effect of Li ⁺ adsorption. By giving the biomimetic lithium ion imprinted membrane the effect of temperature response, the desorption of Li ⁺ by acid washing during the preparation and use of the biomimetic lithium ion imprinted membrane is avoided, and the possible irreversible damage to the adsorption site caused by the acidic eluent is avoided. and the generation of a large amount of elution wastewater.

The beneficial effects of the present invention are:

1. The present invention provides a preparation method of a temperature-responsive biomimetic lithium ion imprinting composite membrane (Li-TSIIM), which adopts PVDF membrane as the base membrane, and PDA formed by self-polymerization of dopamine hydrochloride (DA) as the interface adhesion layer. Grafted thermosensitive functional monomer N,N-diethyl-2-acrylamide (DEA), 12-crown-4 and methacrylic acid (MAA) with specific recognition of lithium ions, prepared Temperature-responsive biomimetic lithium ion imprinted membrane, the biomimetic lithium ion imprinted membrane prepared by this method enables the imprinted membrane to adsorb and desorb target ions at a certain temperature, but has no obvious effect under other conditions. Controllable operation of Li-ion selective adsorption and desorption processes;

2. The temperature-responsive biomimetic lithium ion imprinting composite membrane (Li-TSIIM) prepared in the present invention changes the process of desorbing lithium ions by using the acid-washed imprinting membrane in the traditional process; using temperature to adsorb and desorb lithium ions, not only Avoid the generation of a large amount of elution wastewater, and can reduce the damage of the adsorption site of the biomimetic imprinting membrane;

3. The temperature-responsive bionic lithium ion imprinted composite membrane (Li-TSIIM) prepared by the invention has good selective adsorption capacity for lithium ions, and has the characteristics of strong regeneration and good chemical stability.

The invention can obtain a temperature-responsive bionic lithium ion imprinting composite membrane.

Description of drawings

1 is a process diagram of preparing a temperature-responsive biomimetic lithium-ion imprinted composite membrane in Example 1;

Fig. 2 is a SEM image, a is a PVDF film, b is a PDA@PVDF film prepared in step 1 of Example 1, c is a PDA@PVDF-RAFT film prepared in step 2 of Example 1, and d is a step 3 of Example 1 The prepared PDA@PVDF-RAFT-PDEA film, d is the Li-TSIIM prepared in step 4 of Example 1.

Detailed ways

The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Modifications and substitutions made to the methods, steps or conditions of the present invention without departing from the essence of the present invention all belong to the scope of the present invention.

Embodiment 1: This embodiment is a preparation method of a temperature-responsive bionic lithium ion imprinted composite membrane, which is completed according to the following steps:

1. Preparation of PDA@PVDF membrane:

First dissolve tris(hydroxymethyl)aminomethane in deionized water, then adjust the pH to be alkaline, then add dopamine hydrochloride and a piece of PVDF membrane, and finally stir, after stirring, take out the PVDF membrane, rinse the PVDF membrane with deionized water, Drying again to obtain PDA@PVDF membrane;

2. Preparation of PDA@PVDF-RAFT membrane:

4-Dimethylaminopyridine and trithiocarbonate were dissolved in dichloromethane, and then PDA@PVDF membrane was added. Under the protection of nitrogen atmosphere, dicyclohexylcarbodiimide was added, and the reaction system was sealed again. , under the conditions of stirring and ice bath, after the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain the PDA@PVDF-RAFT membrane;

3. Preparation of PDA@PVDF-RAFT-PDEA membrane:

The PDA@PVDF-RAFT membrane was added to the mixture of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane, and nitrogen was passed through, and then the reaction system was sealed. The reaction was carried out under nitrogen atmosphere and stirring conditions. After the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain a PDA@PVDF-RAFT-PDEA membrane;

4. Preparation of Li-TSIIM:

LiCl and 12-crown ether-4 were added to methanol, and then stirred to obtain a mixed solution; the PDA@PVDF-RAFT-PDEA membrane was put into the mixed solution, and azobisisobutyronitrile, ethylene glycol di Methacrylate and methacrylic acid were introduced into nitrogen, and then the reaction system was sealed, condensed and refluxed under nitrogen atmosphere, stirring and temperature of 75 ° C. After the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain Li-TSIIM, It is a temperature-responsive biomimetic lithium-ion imprinted composite membrane.

Tris(hydroxymethylaminomethane) adopted in the above-mentioned technical scheme, as buffer reagent;

The dopamine hydrochloride (DA) adopted in the above-mentioned technical scheme is used as the interface adhesion material;

The 4-dimethylaminopyridine (DMAP) adopted in the above-mentioned technical scheme, as reaction catalyst;

The trithiocarbonate (RAFT reagent) used in the above technical scheme is used as a synthetic material for a chain transfer reagent;

The methylene chloride that above-mentioned technical scheme adopts, 1,4 dioxane and methanol are used as the background solvent of reaction;

The dicyclohexylcarbodiimide adopted in the above-mentioned technical scheme is used as a low-temperature dehydrating agent;

The N,N-diethyl-2-acrylamide (DEA) adopted in the above technical scheme is used as a temperature-sensitive functional monomer;

Azobisisobutyronitrile (AIBN) adopted in the above-mentioned technical scheme, as free radical initiator;

LiCl adopted in the above-mentioned technical scheme, its function is to provide template Li ⁺ ;

Ethylene glycol dimethacrylate (EGDMA) adopted in the above-mentioned technical scheme, as the crosslinking agent of reaction;

The 12-crown-4 and methacrylic acid (MAA) used in the above technical solution are functional monomers with specific recognition for lithium ions.

Static adsorption experiment:

A certain amount of Li-TSIIM was added to the corresponding test solution and oscillated in a constant temperature water bath at a temperature of 35 °C to investigate the adsorption capacity of Li-TSIIM on Li ⁺ at different initial concentrations of Li ⁺ . After the adsorption was completed, the remaining Li ⁺ in the test solution was measured by inductively coupled plasma spectrometer (ICP), and the adsorption capacity Q _t (mg/g) was measured according to this.

where C ₀ (mg/L) and C _t (mg/L) are the concentration of Li ⁺ in the solution before and after adsorption, respectively, m (g) is the amount of Li-TSIIM added, and V (mL) is the volume of the test solution .

Selective adsorption experiments:

A certain amount of Li-TSIIM was added to the mixed solution containing Li ⁺ and Co ²⁺ , and after shaking in a constant temperature water bath at a temperature of 35 °C for a certain period of time, the selection of Li-TSIIM to Li ⁺ under the interference of Co ²⁺ was investigated. Adsorption performance. The method to test Li-TSIIM adsorption capacity for Li ⁺ and Co ²⁺ is the same as the static adsorption experiment.

Embodiment 2: The difference between this embodiment and Embodiment 1 is: the mass ratio of the tris(hydroxymethylaminomethane) described in step 1 to the volume of deionized water is (0.1g～0.15g): 60mL; step The mass ratio of dopamine hydrochloride described in step 1 to the volume of deionized water is (0.2g～0.25g):60mL; the diameter of the PVDF membrane described in step 1 is 47mm and the thickness is 0.45μm. Other steps are the same as in the first embodiment.

Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that the pH value of the alkalinity described in step 1 is 8.5; the stirring speed described in step 1 is 30r/min～60r /min, the stirring time is 6h-8h; in step 1, the PVDF membrane is rinsed 3-5 times with deionized water, and then dried at a temperature of 50°C-70°C for 1h-2h to obtain a PDA@PVDF membrane. Other steps are the same as in the first or second embodiment.

Embodiment 4: One of the differences between this embodiment and Embodiments 1 to 3 is: the mass ratio of the 4-dimethylaminopyridine described in the step 2 to the volume ratio of dichloromethane is (0.3g～0.5g): 15mL; the volume ratio of the quality of the trithiocarbonate described in the step 2 and the dichloromethane is (0.15g～0.2g): 15mL; the quality of the dicyclohexylcarbodiimide described in the step 2 and the dichloromethane The volume ratio of methyl chloride is (10g～15g):15mL. Other steps are the same as those of the specific embodiments 1 to 3.

Embodiment 5: The difference between this embodiment and Embodiments 1 to 4 is: in step 2, the reaction is performed under the conditions of nitrogen atmosphere, stirring speed of 60r/min～90r/min and ice bath for 20h～24h, and the reaction ends After that, the PVDF membrane was taken out, and the PVDF membrane was washed alternately with deionized water and absolute ethanol for 3 to 5 times, and finally dried at a temperature of 35 °C to 45 °C for 8 h to 12 h to obtain PDA@PVDF- RAFT membrane. The other steps are the same as those in the first to fourth embodiments.

Embodiment 6: The difference between this embodiment and Embodiments 1 to 5 is that the N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4-diethylamide described in step 3 The mass ratio of N,N-diethyl-2-acrylamide and azobisisobutyronitrile in the mixed solution of oxane is 0.1:0.15, and the mass of N,N-diethyl-2-acrylamide is the same as 1 , The volume ratio of 4 dioxane is 0.1g:20mL. Other steps are the same as those of the specific embodiments 1 to 5.

Embodiment 7: The difference between this embodiment and Embodiments 1 to 6 is that: in step 3, the reaction time under the condition of nitrogen gas and stirring is 18h～24h, and the temperature of the reaction is 70°C～75°C; After the reaction, the PVDF membrane was taken out, and the PVDF membrane was washed alternately with deionized water and anhydrous ethanol for 3 to 5 times each, and finally dried at a temperature of 35 °C to 45 °C for 8 h to 12 h to obtain PDA@ PVDF-RAFT-PDEA membrane. Other steps are the same as those of the specific embodiments 1 to 6.

Embodiment 8: The difference between this embodiment and Embodiments 1 to 7 is: the mass ratio of LiCl to methanol described in step 4 is (0.3g～0.7g):90mL; The volume ratio of 12-crown-4 and methanol is (0.3mL～0.7mL): 90mL; in step 4, LiCl and 12-crown-4 are added to methanol, and the stirring speed is 60r/min～ Stir at 90r/min for 0.5h～2h; the mass ratio of azobisisobutyronitrile described in step 4 to the volume of methanol is (0.1g～0.2g):90mL; the ethylene glycol diacetate described in step 4 The volume ratio of methacrylate to methanol is (0.3mL-0.7mL):90mL; the volume ratio of methacrylic acid to methanol described in step 4 is (0.3mL-0.7mL):90mL. Other steps are the same as those of the specific embodiments 1 to 7.

Embodiment 9: The difference between this embodiment and Embodiments 1 to 8 is that: in step 4, in a nitrogen atmosphere, a stirring speed of 30r/min～60r/min and a temperature of 75°C, the reaction is condensed and refluxed for 16h～24h. After the end, the PVDF membrane was taken out, and the PVDF membrane was washed alternately with deionized water and absolute ethanol for 3 to 5 times each, and finally dried at a temperature of 35°C to 45°C for 8h to 12h to obtain Li-TSIIM , which is a temperature-responsive biomimetic lithium-ion imprinted composite membrane. Other steps are the same as those of the specific embodiments 1 to 8.

Embodiment 10: In this embodiment, a temperature-responsive biomimetic lithium ion imprinted composite membrane is used to adsorb Li ⁺ .

Adopt the following examples to verify the beneficial effects of the present invention:

Embodiment 1: A preparation method of a temperature-responsive bionic lithium ion imprinted composite membrane is completed according to the following steps:

1. Preparation of PDA@PVDF membrane:

First, dissolve 0.1 g of tris(hydroxymethyl)aminomethane into 60 mL of deionized water, then adjust the pH to 8.5, then add 0.2 g of dopamine hydrochloride and a piece of PVDF membrane, and finally stir for 6 h at a stirring speed of 60 r/min. The PVDF membrane was taken out, and the PVDF membrane was washed three times with deionized water, and then dried at 60 °C for 1 h to obtain the PDA@PVDF membrane;

The diameter of the PVDF membrane described in step 1 is 47mm and the thickness is 0.45μm;

2. Preparation of PDA@PVDF-RAFT membrane:

Dissolve 0.3g 4-dimethylaminopyridine and 0.15g trithiocarbonate in 15mL dichloromethane, add PDA@PVDF membrane, add 10g dicyclohexylcarbodiimide under the protection of nitrogen atmosphere, and then seal The reaction system was reacted for 24 hours under the conditions of nitrogen atmosphere, stirring speed of 60 r/min and ice bath. After the reaction, the PVDF membrane was taken out, and deionized water and absolute ethanol were used to alternately clean the PVDF membrane, each cleaning 3 times , and finally dried at 45 °C for 12 h to obtain a PDA@PVDF-RAFT membrane;

3. Preparation of PDA@PVDF-RAFT-PDEA membrane:

The PDA@PVDF-RAFT membrane was added to the mixture of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane, and nitrogen was passed through, and then the reaction system was sealed. The reaction was carried out for 24 hours under the conditions of a temperature of 70 °C, a nitrogen atmosphere and a stirring speed of 60 r/min. After the reaction, the PVDF membrane was taken out, and deionized water and anhydrous ethanol were used to alternately clean the PVDF membrane, three times each. Finally, it was dried at 45 °C for 12 h to obtain the PDA@PVDF-RAFT-PDEA membrane;

The mixed solution of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane described in step 3 is 0.1g N,N-diethyl-2-propene Amide, 0.15g azobisisobutyronitrile and 20mL1,4 dioxane mixed;

4. Preparation of Li-TSIIM:

0.3g LiCl and 0.3mL 12-crown-4 were added to 90mL methanol, and then stirred at a stirring speed of 60r/min for 2h to obtain a mixed solution; the PDA@PVDF-RAFT-PDEA membrane was put into the mixed solution , then add 0.1g azobisisobutyronitrile, 0.3mL ethylene glycol dimethacrylate and 0.3mL methacrylic acid, pass nitrogen, and then seal the reaction system, in a nitrogen atmosphere, the stirring speed is 60r/min and the temperature Condensed and refluxed at 75 °C for 16 h. After the reaction, the PVDF membrane was taken out, and the PVDF membrane was washed alternately with deionized water and anhydrous ethanol, three times each, and finally dried at 45 °C for 12 h to obtain Li TSIIM is a temperature-responsive biomimetic lithium-ion imprinted composite membrane.

Static adsorption experiment: Weigh 6 parts of Li-TSIIM prepared in Example 1, put them into 6 centrifuge tubes, and add 10 mL of LiCl solution, the concentrations are 5 mg/L, 10 mg/L, 20 mg/L, 50 mg/L, respectively. L, 100mg/L, 200mg/L, followed by shaking in constant temperature water for 3h at 35°C. After the adsorption was completed, the remaining Li ⁺ in the test solution was measured by inductively coupled plasma spectrometer (ICP), and the adsorption capacity Q _t (mg/g) was measured according to this.

The results show that the adsorption capacity of Li-TSIIM is the largest when the Li ⁺ concentration is 200 mg/L, and the highest saturated adsorption capacity is 38.85 mg/g.

Selective adsorption experiment: Take 0.1 g of Li-TSIIM prepared in Example 1 and add it to 100 mL of a mixed solution containing Li ⁺ and Co ^{2 +} , the concentrations of both ions are 50 mg/L, and shake in a constant temperature water bath at a temperature of 35 °C After a certain period of time, the selective adsorption performance of Li-TSIIM for Li ⁺ under the interference of Co ²⁺ was investigated.

The results show that in the mixed solution, the Li-TSIIM prepared in Example 1 has an adsorption capacity of 36.54 mg/g for Li ⁺ and 8.4 mg/g for Co ²⁺ , which proves that Li-TSIIM has a high efficiency for Li ⁺ . Optional.

Embodiment 2: A preparation method of a temperature-responsive bionic lithium ion imprinted composite membrane is completed according to the following steps:

1. Preparation of PDA@PVDF membrane:

First, dissolve 0.1 g of tris(hydroxymethyl)aminomethane into 60 mL of deionized water, then adjust the pH to 8.5, then add 0.2 g of dopamine hydrochloride and a piece of PVDF membrane, and finally stir for 6 h at a stirring speed of 60 r/min. The PVDF membrane was taken out, and the PVDF membrane was washed three times with deionized water, and then dried at 60 °C for 1 h to obtain the PDA@PVDF membrane;

The diameter of the PVDF membrane described in step 1 is 47mm and the thickness is 0.45μm;

2. Preparation of PDA@PVDF-RAFT membrane:

Dissolve 0.3g 4-dimethylaminopyridine and 0.15g trithiocarbonate in 15mL dichloromethane, add PDA@PVDF membrane, add 10g dicyclohexylcarbodiimide under the protection of nitrogen atmosphere, and then seal The reaction system was reacted for 24 hours under the conditions of nitrogen atmosphere, stirring speed of 60 r/min and ice bath. After the reaction, the PVDF membrane was taken out, and deionized water and absolute ethanol were used to alternately clean the PVDF membrane, each cleaning 3 times , and finally dried at 45 °C for 12 h to obtain a PDA@PVDF-RAFT membrane;

3. Preparation of PDA@PVDF-RAFT-PDEA membrane:

The PDA@PVDF-RAFT membrane was added to the mixture of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane, and nitrogen was passed through, and then the reaction system was sealed. The reaction was carried out for 24 hours under the conditions of a temperature of 70 °C, a nitrogen atmosphere and a stirring speed of 60 r/min. After the reaction, the PVDF membrane was taken out, and deionized water and anhydrous ethanol were used to alternately clean the PVDF membrane, three times each. Finally, it was dried at 45 °C for 12 h to obtain the PDA@PVDF-RAFT-PDEA membrane;

The mixed solution of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane described in step 3 is 0.3g N,N-diethyl-2-propene Amide, 0.15g azobisisobutyronitrile and 20mL1,4 dioxane mixed;

4. Preparation of Li-TSIIM:

0.3g LiCl and 0.5mL 12-crown-4 were added to 90mL methanol, and then stirred at a stirring speed of 60r/min for 2h to obtain a mixed solution; the PDA@PVDF-RAFT-PDEA membrane was put into the mixed solution , then add 0.1g azobisisobutyronitrile, 0.3mL ethylene glycol dimethacrylate and 0.3mL methacrylic acid, pass nitrogen, and then seal the reaction system, in a nitrogen atmosphere, the stirring speed is 60r/min and the temperature Condensed and refluxed at 75 °C for 16 h. After the reaction, the PVDF membrane was taken out, and the PVDF membrane was washed alternately with deionized water and anhydrous ethanol, three times each, and finally dried at 45 °C for 12 h to obtain Li TSIIM is a temperature-responsive biomimetic lithium-ion imprinted composite membrane.

Static adsorption experiment: Weigh 6 parts of Li-TSIIM prepared in Example 2, put them into 6 centrifuge tubes, and add 10 mL of LiCl solution, the concentrations are 5 mg/L, 10 mg/L, 20 mg/L, 50 mg/L, respectively. L, 100mg/L, 200mg/L, followed by shaking in constant temperature water for 3h at 35°C. After the adsorption was completed, the remaining Li ⁺ in the test solution was measured by inductively coupled plasma spectrometer (ICP), and the adsorption capacity Q _t (mg/g) was measured according to this.

The results show that when the Li ⁺ concentration is 200 mg/L, the adsorption capacity of Li-TSIIM is the largest, and the highest saturated adsorption capacity is 42.58 mg/g.

Selective adsorption experiment: Take 0.1 g of Li-TSIIM prepared in Example 2 and add it to 100 mL of a mixed solution containing Li ⁺ and Co ^{2 +} , the concentrations of both ions are 50 mg/L, and shake in a constant temperature water bath at a temperature of 35 °C After a certain period of time, the selective adsorption performance of Li-TSIIM for Li ⁺ under the interference of Co ²⁺ was investigated.

The results show that in the mixed solution, Li-TSIIM has an adsorption capacity of 40.58 mg/g for Li ⁺ and 11.2 mg/g for Co2 ⁺ , which proves that Li-TSIIM has an efficient selectivity for Li ⁺ .

Embodiment 3: A preparation method of a temperature-responsive bionic lithium ion imprinted composite membrane is completed according to the following steps:

1. Preparation of PDA@PVDF membrane:

First, dissolve 0.1 g of tris(hydroxymethyl)aminomethane into 60 mL of deionized water, then adjust the pH to 8.5, then add 0.2 g of dopamine hydrochloride and a piece of PVDF membrane, and finally stir for 6 h at a stirring speed of 60 r/min. The PVDF membrane was taken out, and the PVDF membrane was washed three times with deionized water, and then dried at 60 °C for 1 h to obtain the PDA@PVDF membrane;

The diameter of the PVDF membrane described in step 1 is 47mm and the thickness is 0.45μm;

2. Preparation of PDA@PVDF-RAFT membrane:

Dissolve 0.3g 4-dimethylaminopyridine and 0.15g trithiocarbonate in 15mL dichloromethane, add PDA@PVDF membrane, add 10g dicyclohexylcarbodiimide under the protection of nitrogen atmosphere, and then seal The reaction system was reacted for 24 hours under the conditions of nitrogen atmosphere, stirring speed of 60 r/min and ice bath. After the reaction, the PVDF membrane was taken out, and deionized water and absolute ethanol were used to alternately clean the PVDF membrane, each cleaning 3 times , and finally dried at 45 °C for 12 h to obtain a PDA@PVDF-RAFT membrane;

3. Preparation of PDA@PVDF-RAFT-PDEA membrane:

The PDA@PVDF-RAFT membrane was added to the mixture of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane, and nitrogen was passed through, and then the reaction system was sealed. The reaction was carried out for 24 hours under the conditions of a temperature of 70 °C, a nitrogen atmosphere and a stirring speed of 60 r/min. After the reaction, the PVDF membrane was taken out, and deionized water and anhydrous ethanol were used to alternately clean the PVDF membrane, three times each. Finally, it was dried at 45 °C for 12 h to obtain the PDA@PVDF-RAFT-PDEA membrane;

The mixed solution of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane described in step 3 is 0.5g N,N-diethyl-2-propene Amide, 0.15g azobisisobutyronitrile and 20mL1,4 dioxane mixed;

4. Preparation of Li-TSIIM:

Add 0.3g LiCl and 0.7mL 12-crown-4 to 90mL methanol, and stir at a stirring speed of 60r/min for 2h to obtain a mixed solution; put the PDA@PVDF-RAFT-PDEA membrane into the mixed solution , then add 0.1g azobisisobutyronitrile, 0.3mL ethylene glycol dimethacrylate and 0.3mL methacrylic acid, pass nitrogen, and then seal the reaction system, in a nitrogen atmosphere, the stirring speed is 60r/min and the temperature Condensed and refluxed at 75 °C for 16 h. After the reaction, the PVDF membrane was taken out, and the PVDF membrane was washed alternately with deionized water and anhydrous ethanol, three times each, and finally dried at 45 °C for 12 h to obtain Li TSIIM is a temperature-responsive biomimetic lithium-ion imprinted composite membrane.

Static adsorption experiment: Static adsorption experiment: Weigh 6 parts of Li-TSIIM prepared in Example 3, put them into 6 centrifuge tubes, and add 10 mL of LiCl solution, the concentrations are 5 mg/L, 10 mg/L, 20 mg/L, respectively. L, 50mg/L, 100mg/L, 200mg/L, and then shake in constant temperature water for 3h under the condition of 35℃. After the adsorption was completed, the remaining Li ⁺ in the test solution was measured by inductively coupled plasma spectrometer (ICP), and the adsorption capacity Q _t (mg/g) was measured according to this.

The results show that when the Li ⁺ concentration is 200 mg/L, the adsorption capacity of Li-TSIIM is the largest, and the highest saturated adsorption capacity is 39.76 mg/g.

Selective adsorption experiment: Take 0.1 g of Li-TSIIM prepared in Example 3 and add it to 100 mL of a mixed solution containing Li ⁺ and Co ²⁺ , the concentrations of both ions are 50 mg/L, and the temperature is 35 °C in a constant temperature water bath. After oscillating for a certain time, the selective adsorption performance of Li-TSIIM for Li ⁺ under the interference of Co ²⁺ was investigated.

The results show that in the mixed solution, Li-TSIIM has an adsorption capacity of 38.45 mg/g for Li ⁺ and 10.88 mg/g for Co2 ⁺ , which proves that Li-TSIIM has an efficient selectivity for Li ⁺ .

Claims (7)

1. a preparation method of a temperature-responsive biomimetic lithium ion imprinted composite membrane is characterized in that a preparation method of a temperature-responsive biomimetic lithium ion imprinted composite membrane is accomplished by the following steps: 1. Preparation of PDA@PVDF membrane: First dissolve tris(hydroxymethyl)aminomethane in deionized water, then adjust the pH to be alkaline, then add dopamine hydrochloride and a piece of PVDF membrane, and finally stir, after stirring, take out the PVDF membrane, rinse the PVDF membrane with deionized water, Drying again to obtain PDA@PVDF membrane; 2. Preparation of PDA@PVDF-RAFT membrane: 4-Dimethylaminopyridine and trithiocarbonate were dissolved in dichloromethane, and then PDA@PVDF membrane was added. Under the protection of nitrogen atmosphere, dicyclohexylcarbodiimide was added, and the reaction system was sealed again. , under the conditions of stirring and ice bath, after the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain the PDA@PVDF-RAFT membrane; The mass ratio of the 4-dimethylaminopyridine described in the step 2 to the volume ratio of dichloromethane is (0.3g～0.5g): 15mL; The quality of the trithiocarbonate described in the step 2 and the volume ratio of dichloromethane are (0.15g～0.2g): 15mL; The mass ratio of the dicyclohexylcarbodiimide described in step 2 to the volume ratio of dichloromethane is (10g～15g): 15mL; 3. Preparation of PDA@PVDF-RAFT-PDEA membrane: The PDA@PVDF-RAFT membrane was added to the mixture of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane, and nitrogen was introduced, and then the reaction system was sealed. The reaction was carried out under nitrogen atmosphere and stirring conditions. After the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain the PDA@PVDF-RAFT-PDEA membrane; In the mixed solution of N,N-diethyl-2-acrylamide, azobisisobutyronitrile and 1,4 dioxane described in step 3, N,N-diethyl-2-acrylamide and The mass ratio of azobisisobutyronitrile is 0.1:0.15, the mass ratio of N,N-diethyl-2-acrylamide and 1,4 dioxane is 0.1g:20mL; The reaction time is 18h～24h under the condition of atmosphere and stirring, and the reaction temperature is 70℃～75℃; 4. Preparation of Li-TSIIM: LiCl and 12-crown ether-4 were added to methanol, and then stirred to obtain a mixed solution; the PDA@PVDF-RAFT-PDEA membrane was put into the mixed solution, and azobisisobutyronitrile, ethylene glycol di Methacrylate and methacrylic acid were introduced into nitrogen, and then the reaction system was sealed, condensed and refluxed under nitrogen atmosphere, stirring and temperature of 75 ° C. After the reaction, the PVDF membrane was taken out for cleaning, and finally dried to obtain Li-TSIIM, That is, the temperature-responsive biomimetic lithium-ion imprinted composite membrane; The mass ratio of LiCl described in step 4 to the volume ratio of methanol is (0.3g～0.7g):90mL; The volume ratio of 12-crown-4 to methanol described in step 4 is (0.3mL～0.7mL): 90mL; In step 4, LiCl and 12-crown-4 are added to methanol, and then stirred at a stirring speed of 60r/min～90r/min for 0.5h～2h; The mass ratio of the azobisisobutyronitrile described in step 4 to the volume of methanol is (0.1g～0.2g): 90mL; The volume ratio of ethylene glycol dimethacrylate and methanol described in step 4 is (0.3mL～0.7mL): 90mL; The volume ratio of methacrylic acid to methanol described in step 4 is (0.3mL-0.7mL):90mL. 2. the preparation method of a kind of temperature-responsive biomimetic lithium ion imprinting composite membrane according to claim 1, it is characterized in that the quality of the trimethylolaminomethane described in the step 1 and the volume ratio of deionized water are ( 0.1g～0.15g): 60mL; the mass ratio of dopamine hydrochloride described in step 1 to the volume of deionized water is (0.2g～0.25g): 60mL; the diameter of the PVDF membrane described in step 1 is 47mm, The thickness is 0.45 μm. 3. The preparation method of a temperature-responsive bionic lithium ion imprinted composite membrane according to claim 1, wherein the pH value of the alkalinity described in the step 1 is 8.5; the speed of the stirring described in the step 1 is 8.5. It is 30r/min～60r/min, and the stirring time is 6h～8h; in step 1, use deionized water to rinse the PVDF membrane 3 to 5 times, and then dry it at a temperature of 50℃～70℃ for 1h～2h, A PDA@PVDF membrane was obtained. 4. the preparation method of a kind of temperature-responsive bionic lithium ion imprinted composite membrane according to claim 1, is characterized in that in step 2, under the condition of nitrogen atmosphere, stirring speed is 60r/min～90r/min and ice bath The reaction is carried out for 20h～24h. After the reaction is over, the PVDF membrane is taken out, and the PVDF membrane is washed alternately with deionized water and absolute ethanol, 3 to 5 times each, and finally dried at a temperature of 35℃～45℃ for 8h～ 12h, the PDA@PVDF-RAFT membrane was obtained. 5. the preparation method of a kind of temperature-responsive bionic lithium ion imprinting composite membrane according to claim 1, it is characterized in that after the reaction finishes, PVDF membrane is taken out, use deionized water and absolute ethanol alternately to clean PVDF membrane , washed 3 to 5 times each, and finally dried at a temperature of 35 °C to 45 °C for 8 h to 12 h to obtain a PDA@PVDF-RAFT-PDEA membrane. 6. The preparation method of a temperature-responsive bionic lithium ion imprinted composite membrane according to claim 1, wherein in step 4, in a nitrogen atmosphere, stirring speed is 30r/min～60r/min and temperature is 75 ℃ Condensed and refluxed for 16h-24h. After the reaction, the PVDF membrane was taken out, and the PVDF membrane was washed alternately with deionized water and absolute ethanol, 3 to 5 times each, and finally dried at a temperature of 35°C to 45°C for 8h ~12h, Li-TSIIM is obtained, which is a temperature-responsive biomimetic lithium-ion imprinted composite membrane. 7 . The application of a temperature-responsive biomimetic lithium ion imprinted composite membrane prepared by the preparation method according to claim 1 , wherein a temperature-responsive biomimetic lithium ion imprinted composite membrane is used to adsorb Li ⁺ . 8 .

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