A method for lithium-ion recovery using a pendulum-type electronically controlled lithium-ion recovery device

Abstract

A method for lithium-ion recovery using a pendulum-type electronically controlled lithium-ion recovery device is disclosed. This method addresses the poor separation performance and stability of existing ion-imprinted materials, as well as the problem of decreased adsorption capacity. The recovery method involves sequentially preparing an ion-imprinted polymer, an ion-imprinted polymer / polypyrrole composite, and Li... + -IIP@pyy hybrid film coating electrode, Li + The IIP@pyy hybrid membrane-coated electrode is fixed at the lower end of the swing arm in a pendulum-type electronically controlled lithium-ion recovery device to react with Li in the brine of a salt lake. + Adsorption and desorption. This invention achieves intermittent adsorption and desorption of lithium ions by controlling the potential. Adsorption occurs only when the electrode is immersed in the brine of the salt lake, and desorption occurs in the deionized water regions on both sides, thereby enriching lithium ions. The device has a simple structure, avoids acid washing, and improves adsorption capacity.

Description

Technical Field

[0001] This invention relates to a method for lithium-ion recovery. Background Technology

[0002] Lithium is the lightest of the metals, and due to its unique physical and chemical properties, it has a wide range of applications in the energy sector. Lithium batteries play a crucial role in daily life; they are found in the vast majority of energy storage batteries, including mobile phone batteries, car batteries, and electric vehicle batteries. Lithium can also be used as a lubricant and aerospace fuel.

[0003] Ion imprinting technology is developed based on molecular imprinting technology and has high selectivity for target ions. In actual salt lake brines, in addition to lithium ions, there are also a large number of magnesium ions and other ions. Therefore, selective ion imprinting technology is very suitable for lithium extraction.

[0004] Existing ion-imprinted materials require chemical elution for recovery and recycling, such as acid washing or EDTA elution, which generates secondary pollution. Ion-imprinted materials exhibit low adsorption cycle performance. Acid washing typically uses strong acids such as concentrated sulfuric acid and concentrated hydrofluoric acid, which can break the chemical bonds in the ion-imprinted membrane, damaging its structure and even causing loss of imprinted pore size and selectivity. Furthermore, commonly used cross-linking agents in ion-imprinted membranes, such as formaldehyde and ethylene oxide, are easily decomposed by acid catalysis, leading to a decrease in the degree of cross-linking and thus reducing membrane stability. Therefore, acid washing damages ion-imprinted membranes, reducing their separation performance and stability. Most materials experience a significant decrease in adsorption capacity after five adsorption cycles. Most crown ether-based ion-imprinted materials undergo protonation at low pH conditions, where the O atoms on the crown ether bond with H ions, occupying imprinted sites and leading to a decrease in adsorption capacity. Summary of the Invention

[0005] To address the issues of poor separation performance and stability, as well as declining adsorption capacity, existing ion-imprinted materials, this invention proposes a method for lithium-ion recovery using a pendulum-type electronically controlled lithium-ion recovery device.

[0006] The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device of the present invention is carried out according to the following steps:

[0007] I. Preparation of Ion-Imprinted Polymers

[0008] 12-crown ether-4 and LiNO3 were mixed and dissolved in methanol, and α-methacrylic acid was dissolved in N,N-dimethylformamide. The two solutions were then mixed and reacted at room temperature for 30 minutes. Reduced graphene oxide was then added to the resulting solution and sonicated for 5–10 minutes. Ethylene glycol dimethacrylate and azobisisobutyronitrile were then added, and the mixture was refluxed and stirred at 70°C for 12–16 hours. The solid product was then washed with water and dried to obtain ion-imprinted polymer powder.

[0009] The mass ratio of 12-crown ether-4 to the molar ratio of LiNO3 is (0.39–0.41) g : 0.002 mol;

[0010] The mass ratio of 12-crown ether-4 to the volume ratio of methanol is (0.39–0.41): 20 mL;

[0011] The mass ratio of 12-crown ether-4 to the molar ratio of α-methacrylic acid is (0.39–0.41):0.002 mol;

[0012] The mass ratio of 12-crown ether-4 to the volume ratio of N,N-dimethylformamide is (0.39–0.41):40 mL;

[0013] The mass ratio of 12-crown ether-4 to reduced graphene oxide is (0.39–0.41):0.5;

[0014] The mass ratio of 12-crown ether-4 to the volume ratio of ethylene glycol dimethacrylate is (0.39–0.41):4 mL;

[0015] The mass ratio of 12-crown ether-4 to azobisisobutyronitrile is (0.39–0.41):130;

[0016] II. Preparation of IIP@ppy

[0017] The ion-imprinted polymer powder obtained in step one was added to anhydrous ethanol and stirred. Then, pyrrole and FeCl3 solution were added and reacted under ice bath conditions for 12-16 h. The resulting solid product was washed with 1 mol / L nitric acid and finally dried to obtain the ion-imprinted polymer / polypyrrole composite.

[0018] The mass ratio of the ion-imprinted polymer powder to the volume of anhydrous ethanol is (0.5-0.7) g : (5-30) mL;

[0019] The mass ratio of the ion-imprinted polymer powder to the volume of pyrrole is (0.5-0.7) g : (0.4-0.6) mL;

[0020] The mass ratio of the ion-imprinted polymer powder to the volume of the FeCl3 solution is (0.5-0.7) g : (15-20) mL, and the concentration of the FeCl3 solution is 1 mol / L.

[0021] III. Li + Preparation of -IIP@pyy

[0022] Polyvinylidene fluoride, graphite, and the ion-imprinted polymer / polypyrrole composite obtained in step two were mixed and thoroughly ground to obtain a mixed powder. The mixed powder was then added to 1-methyl-2-pyrrolidone and stirred for 12 hours. The resulting viscous slurry was then uniformly coated onto a titanium mesh substrate and finally dried to obtain Li. + -IIP@pyy hybrid film coating electrode; the obtained Li + The -IIP@pyy hybrid film-coated electrode is placed inside the electrolytic cell and connected to the positive terminal of the power supply. Simultaneously, a counter electrode is placed inside the electrolytic cell and connected to the negative terminal of the power supply. Upon energization, Li... + -IIP@pyy hybrid film coated electrode Li + Removal;

[0023] The mass ratio of the ion-imprinted polymer / polypyrrole complex to the volume ratio of 1-methyl-2-pyrrolidone is (0.049–0.051) g: 15.15 mL;

[0024] The mass ratio of the ion-imprinted polymer / polypyrrole composite, polyvinylidene fluoride, and graphite is (8-10):1:1;

[0025] IV. Assemble a pendulum-type electronically controlled lithium-ion recovery device

[0026] Li + -IIP@pyy hybrid membrane coated electrode 6 is fixed at the lower end of the swing arm 5 in the pendulum-type electronically controlled lithium-ion recovery device;

[0027] The pendulum-type electronically controlled lithium-ion recovery device consists of a reaction container 1, a deionized water nozzle 2, a brine tank 3, a left deionized water tank 4, a swing arm 5, and a right deionized water tank 7. The brine tank 3, the left deionized water tank 4, and the right deionized water tank 7 are arranged inside the reaction container 1. The brine tank 3 is positioned between the left deionized water tank 4 and the right deionized water tank 7. The swing arm 5 is positioned above the brine tank 3, and a rotating shaft 8 is provided at the upper end of the swing arm 5. The rotating shaft 8 is connected to the drive mechanism. Deionized water nozzles 2 are respectively provided above the left deionized water tank 4 and in the right deionized water tank 7.

[0028] V. Lithium-ion recovery

[0029] The swing arm 5 is swung by a drive mechanism, when Li +When the -IIP@pyy hybrid film-coated electrode is immersed in the brine of the salt lake in the brine tank 3, Li + The -IIP@pyy hybrid film-coated electrode is connected to the negative terminal of the power supply, where lithium ions are adsorbed; when Li + When the -IIP@pyy hybrid film-coated electrode leaves the brine and reaches below the nozzle, the Li... + -IIP@pyy hybrid film coated electrode connected to the negative terminal of the power supply or Li + The -IIP@pyy hybrid film coating electrode is connected to the positive terminal of the power supply, and deionized water is sprayed from the deionized water nozzle 2 to achieve lithium ion desorption.

[0030] The principle of this invention is as follows:

[0031] Polypyrrole (PP) is a heterocyclic conjugated conductive polymer with high conductivity, reversible electrochemical redox properties, and strong charge transfer capabilities. Simultaneously, PPP can capture / release dopant ions during electrochemical redox reactions and balance the charge in the film. Furthermore, depending on the synthesis conditions, PPP can exchange with anions and cations. Based on the provided potential difference, PPP can carry different types of charges, utilizing this to generate electrostatic adsorption for cations such as lithium ions. Furthermore, under power-off conditions, it can generate opposite forces on lithium ions and other cations, thereby achieving desorption. Ion imprinting relies on the formation of specific adsorption sites for target ions, thus achieving specificity and selectivity. This invention utilizes the electrochemical properties of PPP and the selectivity of ion-imprinted polymers, combining ion imprinting with electropolymerization technology to prepare Li... + The electrode is coated with an IIP@pyy hybrid film, and the reduced graphene oxide is functionalized with 12C4. When a reduction potential is provided, lithium ions are adsorbed; when the power is off, lithium ions are desorbed. Both adsorption and desorption occur to maintain electroneutrality in the solution. This invention provides a novel method for the selective adsorption and desorption of lithium ions.

[0032] The beneficial effects of this invention are as follows:

[0033] 1. Compared with traditional recycling methods such as adsorption, the present invention has better selectivity, greatly improves the adsorption capacity for lithium ions, and reduces the influence of other ions in the solution during the adsorption process.

[0034] 2. This invention achieves intermittent adsorption and desorption of lithium ions by controlling the potential. Adsorption occurs only when the electrode is immersed in the brine of the salt lake, and desorption occurs in the deionized water areas on both sides, thereby achieving the purpose of enriching lithium ions. The device has a simple structure, and the process can be automated by computer control.

[0035] 3. This invention utilizes the electrochemical properties of polypyrrole to enable the obtained ion-imprinted polymer electrode to conduct electricity. Depending on the applied potential, it can affect Li when a reduction potential is applied. + Selective adsorption and desorption of lithium ions at open circuit potential avoids acid washing compared to other ion-imprinted polymers, reduces damage to electrodes, and improves the stability of ion-imprinted materials.

[0036] 4. This invention generates an electric field after energization, causing H to... + The coordinate bond between the H atom and the oxygen atom breaks, resulting in H + Unable to directly and stably bond with oxygen atoms, it exhibits deprotonation, thus reducing the impact of protonation on adsorption capacity caused by ion-imprinted polymers using crown ethers as functional monomers, and improving the adsorption capacity for lithium ions. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the pendulum-type electronically controlled lithium-ion recovery device in Example 1. Detailed Implementation

[0038] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0039] Specific Implementation Method 1: This implementation method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device is carried out according to the following steps:

[0040] I. Preparation of Ion-Imprinted Polymers

[0041] 12-crown ether-4 and LiNO3 were mixed and dissolved in methanol, and α-methacrylic acid was dissolved in N,N-dimethylformamide. The two solutions were then mixed and reacted at room temperature for 30 minutes. Reduced graphene oxide was then added to the resulting solution and sonicated for 5–10 minutes. Ethylene glycol dimethacrylate and azobisisobutyronitrile were then added, and the mixture was refluxed and stirred at 70°C for 12–16 hours. The solid product was then washed with water and dried to obtain ion-imprinted polymer powder.

[0042] The mass ratio of 12-crown ether-4 to the molar ratio of LiNO3 is (0.39–0.41) g : 0.002 mol;

[0043] The mass ratio of 12-crown ether-4 to the volume ratio of methanol is (0.39–0.41): 20 mL;

[0044] The mass ratio of 12-crown ether-4 to the molar ratio of α-methacrylic acid is (0.39–0.41):0.002 mol;

[0045] The mass ratio of 12-crown ether-4 to the volume ratio of N,N-dimethylformamide is (0.39–0.41):40 mL;

[0046] The mass ratio of 12-crown ether-4 to reduced graphene oxide is (0.39–0.41):0.5;

[0047] The mass ratio of 12-crown ether-4 to the volume ratio of ethylene glycol dimethacrylate is (0.39–0.41):4 mL;

[0048] The mass ratio of 12-crown ether-4 to azobisisobutyronitrile is (0.39–0.41):130;

[0049] II. Preparation of IIP@ppy

[0050] The ion-imprinted polymer powder obtained in step one was added to anhydrous ethanol and stirred. Then, pyrrole and FeCl3 solution were added and reacted under ice bath conditions for 12-16 h. The resulting solid product was washed with 1 mol / L nitric acid and finally dried to obtain the ion-imprinted polymer / polypyrrole composite.

[0051] The mass ratio of the ion-imprinted polymer powder to the volume of anhydrous ethanol is (0.5-0.7) g : (5-30) mL;

[0052] The mass ratio of the ion-imprinted polymer powder to the volume of pyrrole is (0.5-0.7) g : (0.4-0.6) mL;

[0053] The mass ratio of the ion-imprinted polymer powder to the volume of the FeCl3 solution is (0.5-0.7) g : (15-20) mL, and the concentration of the FeCl3 solution is 1 mol / L.

[0054] III. Li + Preparation of -IIP@pyy

[0055] Polyvinylidene fluoride, graphite, and the ion-imprinted polymer / polypyrrole composite obtained in step two were mixed and thoroughly ground to obtain a mixed powder. The mixed powder was then added to 1-methyl-2-pyrrolidone and stirred for 12 hours. The resulting viscous slurry was then uniformly coated onto a titanium mesh substrate and finally dried to obtain Li. + -IIP@pyy hybrid film coating electrode; the obtained Li + The -IIP@pyy hybrid film-coated electrode is placed inside the electrolytic cell and connected to the positive terminal of the power supply. Simultaneously, a counter electrode is placed inside the electrolytic cell and connected to the negative terminal of the power supply. Upon energization, Li... + -IIP@pyy hybrid film coated electrode Li + Removal;

[0056] The mass ratio of the ion-imprinted polymer / polypyrrole complex to the volume ratio of 1-methyl-2-pyrrolidone is (0.049–0.051) g: 15.15 mL;

[0057] The mass ratio of the ion-imprinted polymer / polypyrrole composite, polyvinylidene fluoride, and graphite is (8-10):1:1;

[0058] IV. Assemble a pendulum-type electronically controlled lithium-ion recovery device

[0059] Li + -IIP@pyy hybrid membrane coated electrode 6 is fixed at the lower end of the swing arm 5 in the pendulum-type electronically controlled lithium-ion recovery device;

[0060] The pendulum-type electronically controlled lithium-ion recovery device consists of a reaction container 1, a deionized water nozzle 2, a brine tank 3, a left deionized water tank 4, a swing arm 5, and a right deionized water tank 7. The brine tank 3, the left deionized water tank 4, and the right deionized water tank 7 are arranged inside the reaction container 1. The brine tank 3 is positioned between the left deionized water tank 4 and the right deionized water tank 7. The swing arm 5 is positioned above the brine tank 3, and a rotating shaft 8 is provided at the upper end of the swing arm 5. The rotating shaft 8 is connected to the drive mechanism. Deionized water nozzles 2 are respectively provided above the left deionized water tank 4 and in the right deionized water tank 7.

[0061] V. Lithium-ion recovery

[0062] The swing arm 5 is swung by a drive mechanism, when Li + When the -IIP@pyy hybrid film-coated electrode is immersed in the brine of the salt lake in the brine tank 3, Li + The -IIP@pyy hybrid film-coated electrode is connected to the negative terminal of the power supply, where lithium ions are adsorbed; when Li + When the -IIP@pyy hybrid film-coated electrode leaves the brine and reaches below the nozzle, the Li... + -IIP@pyy hybrid film coated electrode connected to the negative terminal of the power supply or Li + The -IIP@pyy hybrid film coating electrode is connected to the positive terminal of the power supply, and deionized water is sprayed from the deionized water nozzle 2 to achieve lithium ion desorption.

[0063] 1. Compared with traditional recovery methods such as adsorption, this embodiment has better selectivity, greatly improves the adsorption capacity for lithium ions, and reduces the influence of other ions in the solution during the adsorption process.

[0064] 2. This embodiment achieves intermittent adsorption and desorption of lithium ions by controlling the potential. Adsorption occurs only when the electrode is immersed in the brine of the salt lake, and desorption occurs in the deionized water areas on both sides, thereby achieving the purpose of enriching lithium ions. The device has a simple structure, and the process can be automated by computer control.

[0065] 3. This embodiment utilizes the electrochemical properties of polypyrrole to enable the obtained ion-imprinted polymer electrode to conduct electricity. Depending on the applied potential, the Li... + Selective adsorption and desorption of lithium ions at open circuit potential avoids acid washing compared to other ion-imprinted polymers, reduces damage to electrodes, and improves the stability of ion-imprinted materials.

[0066] 4. In this embodiment, an electric field is generated after energization, causing H to... + The coordinate bond between the H atom and the oxygen atom breaks, resulting in H + Unable to directly and stably bond with oxygen atoms, it exhibits deprotonation, thus reducing the impact of protonation on adsorption capacity caused by ion-imprinted polymers using crown ethers as functional monomers, and improving the adsorption capacity for lithium ions.

[0067] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: in step one, the mass ratio of 12-crown ether-4 to the molar ratio of LiNO3 is 0.4g:0.002mol; the mass ratio of 12-crown ether-4 to the volume ratio of methanol is 0.4g:20mL; the mass ratio of 12-crown ether-4 to the molar ratio of α-methacrylic acid is 0.4g:0.002mol; the mass ratio of 12-crown ether-4 to the volume ratio of N,N-dimethylformamide is 0.4g:40mL; the mass ratio of 12-crown ether-4 to the mass ratio of reduced graphene oxide is 0.4g:0.5; the mass ratio of 12-crown ether-4 to the volume ratio of ethylene glycol dimethacrylate is 0.4g:4mL; and the mass ratio of 12-crown ether-4 to the mass ratio of azobisisobutyronitrile is 0.4g:130.

[0068] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the drying process described in step 1 involves drying at 70°C for 6 hours.

[0069] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: In step two, the mass ratio of the ion-imprinted polymer powder to the volume of anhydrous ethanol is (0.5-0.7) g : (5-30) mL. The mass ratio of the ion-imprinted polymer powder to the volume of pyrrole is (0.5-0.7) g : (0.4-0.6) mL; the mass ratio of the ion-imprinted polymer powder to the volume of FeCl3 solution is (0.5-0.7) g : (15-20) mL, and the concentration of the FeCl3 solution is 1 mol / L.

[0070] Specific Implementation Method 5: This implementation method differs from one of the specific implementation methods 1 to 4 in that the mass ratio of the ion-imprinted polymer / polypyrrole complex to the volume of 1-methyl-2-pyrrolidone in step 3 is 0.05 g: 15.15 mL.

[0071] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the mass ratio of the ion-imprinted polymer / polypyrrole composite, polyvinylidene fluoride, and graphite in step three is 8:1:1.

[0072] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the voltage applied in step three is 0.4 to 1.2V.

[0073] Specific Implementation Method Eight: This implementation method differs from one of the specific implementation methods one to seven in that the driving mechanism described in step four is a motor.

[0074] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the drying temperature in step three is 60°C.

[0075] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the drying temperature in step 2 is 60°C.

[0076] Example 1:

[0077] The method for recovering lithium ions using a pendulum-type electronically controlled lithium-ion recovery device is carried out according to the following steps:

[0078] I. Preparation of Ion-Imprinted Polymers

[0079] 0.4 g of 12-crown ether-4 and 0.002 mol of LiNO3 were mixed and dissolved in 20 mL of methanol, and 0.002 mol of α-methacrylic acid was dissolved in 40 mL of N,N-dimethylformamide. The two solutions were then mixed and reacted at room temperature for 30 minutes. 0.5 g of reduced graphene oxide was then added to the resulting solution and sonicated for 5 minutes. Subsequently, 4 mL of ethylene glycol dimethacrylate and 130 g of azobisisobutyronitrile were added, and the mixture was refluxed and stirred at 70 °C for 16 hours. The solid product was then washed with water and dried to obtain ion-imprinted polymer powder.

[0080] The drying process involves drying at 70°C for 6 hours.

[0081] II. Preparation of IIP@ppy

[0082] 0.6 g of ion-imprinted polymer powder obtained in step one was added to 30 mL of anhydrous ethanol and stirred. Then, 0.6 mL of pyrrole and 20 mL of 1 mol / L FeCl3 solution were added. The mixture was reacted in an ice bath for 12 h. The resulting solid product was washed with 1 mol / L nitric acid and then dried in an oven at 60 °C until no residual solvent was found, thus obtaining the ion-imprinted polymer / polypyrrole composite.

[0083] III. Li + Preparation of -IIP@pyy

[0084] Polyvinylidene fluoride, graphite, and 0.05 g of the ion-imprinted polymer / polypyrrole composite obtained in step two were mixed and thoroughly ground to obtain a mixed powder. The mixed powder was added to 15.15 mL of 1-methyl-2-pyrrolidone and stirred for 12 h. The resulting viscous slurry was then uniformly coated onto a titanium mesh substrate and finally vacuum dried at 60 °C for 24 h to obtain Li. + -IIP@pyy hybrid film coating electrode; the obtained Li + The -IIP@pyy hybrid film-coated electrode is placed inside the electrolytic cell and connected to the positive terminal of the power supply. Simultaneously, a counter electrode is placed inside the electrolytic cell and connected to the negative terminal of the power supply. After applying a current (0.8V), Li0.8 is achieved. + -IIP@pyy hybrid film coated electrode Li + Removal;

[0085] The mass ratio of the ion-imprinted polymer / polypyrrole composite, polyvinylidene fluoride, and graphite is 8:1:1.

[0086] IV. Assemble a pendulum-type electronically controlled lithium-ion recovery device

[0087] Li + -IIP@pyy hybrid membrane coated electrode 6 is fixed at the lower end of the swing arm 5 in the pendulum-type electronically controlled lithium-ion recovery device;

[0088] The pendulum-type electrically controlled lithium-ion recovery device consists of a reaction container 1, a deionized water nozzle 2, a brine tank 3, a left deionized water tank 4, a swing arm 5, and a right deionized water tank 7. The brine tank 3, the left deionized water tank 4, and the right deionized water tank 7 are arranged inside the reaction container 1, with the brine tank 3 positioned between the left deionized water tank 4 and the right deionized water tank 7. The swing arm 5 is positioned above the brine tank 3, and a rotating shaft 8 is provided at the upper end of the swing arm 5, which is connected to a drive mechanism. Deionized water nozzles 2 are respectively provided above the left deionized water tank 4 and the right deionized water tank 7. The drive mechanism is a NEMA17 stepper motor.

[0089] V. Lithium-ion recovery

[0090] The swing arm 5 is swung by a drive mechanism, when Li + When the -IIP@pyy hybrid film-coated electrode is immersed in the brine of the salt lake in the brine tank 3, Li + The -IIP@pyy hybrid film-coated electrode is connected to the negative terminal of the power supply, where lithium ions are adsorbed; when Li + When the -IIP@pyy hybrid membrane-coated electrode leaves the brine and reaches below the nozzle, it disconnects from the negative terminal of the power supply and uses deionized water nozzle 2 to spray deionized water to achieve lithium ion desorption.

[0091] The half-period of the oscillation is: Li + The -IIP@pyy hybrid film-coated electrode 6 was immersed in the brine of the salt lake in the brine tank 3 for 1.5 hours, and then the swing arm 5 was slowly rotated for 0.5 hours. At this time, Li + The -IIP@pyy hybrid film coated electrode 6 is located below the nozzle. With the power off, deionized water is sprayed through the deionized water nozzle 2 for 3.75 hours, followed by rotation of the swing arm 5 for 0.5 hours until Li... + The -IIP@pyy hybrid film-coated electrode 6 is immersed in the brine in the brine tank 3 of the salt lake.

[0092] Adsorption capacity test: The adsorption capacity was measured under laboratory conditions. The brine used was simulated brine, with LiCl concentrations of 200 mg / L, NaCl concentrations of 200 mg / L, KCl concentrations of 200 mg / L, and MgCl concentrations of 200 mg / L. In a two-electrode system controlled by a VMP3 potentiometer, using a wire mesh and the LiCl sample from this embodiment... + The -IIP@pyy film-coated electrodes were connected to the positive and negative terminals of a potentiometer, respectively. During adsorption, the negative electrode voltage was 0.8V, and a positive voltage of 1.0V was applied to the positive electrode. The adsorption time was 1.5 hours. The Li in this embodiment was measured... +The adsorption capacity of -IIP@ppy reached 97.21 mg.g -1 .

[0093] Cyclic adsorption performance test: The simulated salt lake brine in Example 1 was replaced with a 200 mg / L LiCl solution; the adsorption voltage for lithium ion adsorption was 0.8 V, and the desorption was Li + The -IIP@pyy hybrid film-coated electrode 6 is connected to the positive terminal of the power supply, with an applied voltage of 1.0V. Each cycle consists of 1.5 hours of adsorption followed by 3.75 hours of desorption. After five cycles, the adsorption capacity decreased by only 2.44%, while after the twentieth cycle, the adsorption capacity decreased by 12.81%. This is attributed to the high-voltage resistance of RGO and the stability of its two-dimensional structure, which improves the overall conductivity of the material and avoids oxidation of ppy under high voltage conditions. Therefore, Li... + -IIP@ppy has good cyclic adsorption performance and can be reused multiple times.

Claims

1. A method for lithium-ion recovery using a pendulum-type electronically controlled lithium-ion recovery device, characterized in that: The method for recovering lithium ions using a pendulum-type electronically controlled lithium-ion recovery device is carried out according to the following steps: I. Preparation of Ion-Imprinted Polymers 12-crown ether-4 and LiNO3 were mixed and dissolved in methanol, and α-methacrylic acid was dissolved in N,N-dimethylformamide. The two solutions were then mixed and reacted at room temperature for 30 minutes. Reduced graphene oxide was then added to the resulting solution and sonicated for 5–10 minutes. Ethylene glycol dimethacrylate and azobisisobutyronitrile were then added, and the mixture was refluxed and stirred at 70°C for 12–16 hours. The solid product was then washed with water and dried to obtain ion-imprinted polymer powder. The mass ratio of 12-crown ether-4 to the molar ratio of LiNO3 is (0.39–0.41) g : 0.002 mol; The mass ratio of 12-crown ether-4 to methanol volume is (0.39–0.41): 20 mL; The mass ratio of 12-crown ether-4 to the molar ratio of α-methacrylic acid is (0.39–0.41):0.002 mol; The mass ratio of 12-crown ether-4 to the volume ratio of N,N-dimethylformamide is (0.39–0.41):40 mL; The mass ratio of 12-crown ether-4 to reduced graphene oxide is (0.39–0.41):0.5; The mass ratio of 12-crown ether-4 to the volume ratio of ethylene glycol dimethacrylate is (0.39–0.41):4 mL; The mass ratio of 12-crown ether-4 to azobisisobutyronitrile is (0.39–0.41):130; II. Preparation of IIP@ppy The ion-imprinted polymer powder obtained in step one was added to anhydrous ethanol and stirred. Then, pyrrole and FeCl3 solution were added and reacted under ice bath conditions for 12-16 h. The resulting solid product was washed with 1 mol / L nitric acid and finally dried to obtain the ion-imprinted polymer / polypyrrole composite. The mass ratio of the ion-imprinted polymer powder to the volume of anhydrous ethanol is (0.5-0.7) g : (5-30) mL; The mass ratio of the ion-imprinted polymer powder to the volume ratio of pyrrole is (0.5-0.7) g : (0.4-0.6) mL; The mass ratio of the ion-imprinted polymer powder to the volume of the FeCl3 solution is (0.5-0.7) g : (15-20) mL, and the concentration of the FeCl3 solution is 1 mol / L. III. Li + Preparation of IIP@pyy Polyvinylidene fluoride, graphite, and the ion-imprinted polymer / polypyrrole composite obtained in step two were mixed and thoroughly ground to obtain a mixed powder. The mixed powder was then added to 1-methyl-2-pyrrolidone and stirred for 12 hours. The resulting viscous slurry was then uniformly coated onto a titanium mesh substrate and finally dried to obtain Li. + -IIP@pyy hybrid film coating electrode; the obtained Li + The -IIP@pyy hybrid film-coated electrode is placed inside the electrolytic cell and connected to the positive terminal of the power supply. Simultaneously, a counter electrode is placed inside the electrolytic cell and connected to the negative terminal of the power supply. Upon energization, Li... + -IIP@pyy hybrid film coated electrode Li + Removal; The mass ratio of the ion-imprinted polymer / polypyrrole complex to the volume ratio of 1-methyl-2-pyrrolidone is (0.049–0.051) g: 15.15 mL; The mass ratio of the ion-imprinted polymer / polypyrrole composite, polyvinylidene fluoride, and graphite is (8-10):1:1; IV. Assemble a pendulum-type electronically controlled lithium-ion recovery device Li + -IIP@pyy hybrid film coated electrode (6) is fixed at the lower end of the pendulum arm (5) in the pendulum-type electronically controlled lithium-ion recovery device; The pendulum-type electronically controlled lithium-ion recovery device consists of a reaction container (1), a deionized water nozzle (2), a salt lake brine tank (3), a left deionized water tank (4), a swing arm (5), and a right deionized water tank (7). The salt lake brine tank (3), the left deionized water tank (4), and the right deionized water tank (7) are located inside the reaction container (1). The salt lake brine tank (3) is located between the left deionized water tank (4) and the right deionized water tank (7). The swing arm (5) is located above the salt lake brine tank (3). A rotating shaft (8) is provided at the upper end of the swing arm (5), and the rotating shaft (8) is connected to the drive mechanism. Deionized water nozzles (2) are respectively provided above the left deionized water tank (4) and the right deionized water tank (7). V. Lithium-ion recovery The swing arm (5) is swung by a drive mechanism, when Li + When the -IIP@pyy hybrid film coated electrode is immersed in the brine in the brine tank (3), Li + The -IIP@pyy hybrid film-coated electrode is connected to the negative terminal of the power supply, where lithium ions are adsorbed. When Li + When the -IIP@pyy hybrid film-coated electrode leaves the brine and reaches below the nozzle, the Li... + -IIP@pyy hybrid film coated electrode connected to the negative terminal of the power supply or Li + The -IIP@pyy hybrid film coating electrode is connected to the positive terminal of the power supply, and deionized water is sprayed using a deionized water nozzle (2) to achieve lithium ion desorption.

2. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: In step one: The mass ratio of 12-crown ether-4 to the molar ratio of LiNO3 is 0.4 g : 0.002 mol; The mass ratio of 12-crown ether-4 to the volume ratio of methanol is 0.4 g: 20 mL; The mass ratio of 12-crown ether-4 to α-methacrylic acid is 0.4 g : 0.002 mol; The mass ratio of 12-crown ether-4 to the volume ratio of N,N-dimethylformamide is 0.4 g: 40 mL; The mass ratio of the 12-crown ether-4 to the reduced graphene oxide is 0.4 g: 0.5 g; The mass ratio of 12-crown ether-4 to the volume ratio of ethylene glycol dimethacrylate is 0.4 g: 4 mL; The mass ratio of 12-crown ether-4 to azobisisobutyronitrile is 0.4:

130.

3. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: The drying process described in step one involves drying at 70°C for 6 hours.

4. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: In step two: The mass ratio of the ion-imprinted polymer powder to the volume of anhydrous ethanol is (0.5-0.7) g : (5-30) mL; The mass ratio of the ion-imprinted polymer powder to the volume ratio of pyrrole is (0.5-0.7) g : (0.4-0.6) mL; The mass ratio of the ion-imprinted polymer powder to the volume of the FeCl3 solution is (0.5-0.7) g : (15-20) mL, and the concentration of the FeCl3 solution is 1 mol / L.

5. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: The mass ratio of the ion-imprinted polymer / polypyrrole complex to the volume of 1-methyl-2-pyrrolidone in step three is 0.05 g: 15.15 mL.

6. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: In step three, the mass ratio of the ion-imprinted polymer / polypyrrole composite, polyvinylidene fluoride, and graphite is 8:1:

1.

7. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: The voltage applied in step three is 0.4 to 1.2V.

8. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: The driving mechanism described in step four is a motor.

9. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: The drying temperature in step three is 60℃.

10. The method for lithium ion recovery using a pendulum-type electronically controlled lithium ion recovery device according to claim 1, characterized in that: The drying temperature in step two is 60℃.

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