Method for purifying scandium based on graphene oxide layered membrane adsorption

Abstract

The application provides a method for adsorbing and purifying scandium based on a graphene oxide layered membrane, and the method comprises the following steps: after adjusting the pH of a scandium-containing solution, using a modified graphene oxide layered membrane to adsorb and filter the scandium-containing solution; after using an EDTA-containing buffer solution to flush the modified graphene oxide layered membrane, using an acid solution to flush the modified graphene oxide layered membrane to obtain a scandium-rich solution. The scandium-containing solution is adsorbed and filtered by using the modified graphene oxide layered membrane, and scandium ions and part of impurity ions are intercepted on the surface of the membrane, so that the scandium and the impurity ions are preliminarily separated; then the modified graphene oxide layered membrane is flushed by using the EDTA-containing buffer solution; finally, the high-purity scandium-rich solution can be obtained by flushing with the acid solution.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology and relates to a method for purifying scandium by adsorption using a layered graphene oxide film. Background Technology

[0002] Scandium is a scarce strategic rare earth metal with unique physicochemical properties such as high melting point, low density, excellent electrical conductivity, and strong catalytic activity. It has irreplaceable application value in high-tech fields such as aerospace, high-end alloy preparation, new energy catalysis, electronic semiconductors, and special ceramics. In nature, scandium exists mostly as a by-product in ilmenite, bauxite, rare earth ores, and nickel ores, rarely forming independent deposits. This results in industrial scandium-containing feed solutions generally having low scandium content and complex impurity composition, often accompanied by large amounts of conventional impurity ions such as aluminum and iron ions, severely restricting the purification, enrichment, and efficient utilization of scandium. Therefore, developing efficient, low-consumption, and highly selective scandium separation and purification technologies is the core key to achieving efficient industrial-scale recovery of scandium resources.

[0003] Currently, the main industrial purification and separation processes for scandium-containing solutions include solvent extraction, ion exchange resin adsorption, and traditional membrane separation.

[0004] Existing scandium purification technologies generally suffer from technical challenges such as poor separation selectivity, incomplete impurity removal, complex process flow, poor environmental performance, low product purity, and insufficient material cycle stability. These challenges make it difficult to achieve efficient and accurate separation of scandium ions from core impurities such as aluminum and iron in scandium-containing solutions, which severely limits the efficient recovery and high-value utilization of low-grade scandium-containing resources. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for purifying scandium based on the adsorption of a graphene oxide layered membrane. This invention uses a modified graphene oxide layered membrane to adsorb and filter scandium-containing solutions, retaining scandium ions and some impurity ions on the membrane surface, achieving initial separation of scandium and impurity ions. Subsequently, the modified graphene oxide layered membrane is rinsed with a buffer solution containing EDTA. Since impurity ions exhibit weak adsorption to the membrane while scandium ions exhibit strong adsorption, EDTA can complex and elute the impurity ions, while scandium ions remain adsorbed on the membrane surface. Finally, rinsing with an acid solution yields a high-purity scandium-rich solution.

[0006] To achieve this objective, the present invention adopts the following technical solution: This invention provides a method for purifying scandium by adsorption using a graphene oxide layered membrane, the method comprising the following steps: Provides modified graphene oxide layered films and scandium-containing solutions; After adjusting the pH of the scandium-containing solution, the solution was adsorbed and filtered using a modified graphene oxide layered membrane. After a first rinse with a buffer solution containing EDTA, the modified graphene oxide layered membrane was rinsed a second time with an acid solution to obtain a scandium-rich solution.

[0007] This invention adjusts the pH of the scandium-containing solution and then uses a modified graphene oxide layered membrane for adsorption filtration. Because the ion orientation is weak during adsorption filtration (the ion only flows in the direction of solution flow), the Scandium in the solution... 3+ and some AI 3+ and Fe 3+ Metal ions are all trapped on one side of the modified graphene oxide layered film, among which, Sc 3+ Due to its strong adsorption on the film surface through interaction with the modified graphene oxide layered film, Al... 3+ and Fe 3+ When metal ions are only weakly adsorbed on the membrane surface, a buffer solution containing EDTA is used as the rinsing solution. EDTA is a broad-spectrum, strong complexing agent that can bind with Al. 3+ and Fe 3+ When metal ions undergo complexation to form stable water-soluble complexes, they are eluted during rinsing due to this complexation. 3+ It remains on the membrane surface and is finally rinsed with an acid solution to destroy the Sc. 3+ The interaction between the modified graphene oxide layered film and the Sc will bind firmly. 3+ Complete desorption yields a high-purity scandium-rich solution.

[0008] Preferably, the modified graphene oxide layered film is prepared by the following method: Graphene oxide is mixed with a solvent to obtain a graphene oxide dispersion. The graphene oxide dispersion is then heat-treated to obtain a pretreated graphene oxide dispersion. The pretreated graphene oxide dispersion, diamine monomer, and amino acid are mixed and subjected to a modification reaction to obtain a modified graphene oxide dispersion. The modified graphene oxide dispersion is coated onto a substrate surface and vacuum-dried to obtain the modified graphene oxide layered film.

[0009] Graphene oxide possesses a unique two-dimensional layered structure, controllable interlayer spacing, abundant oxygen-containing functional groups, and excellent physicochemical stability. This invention first partially reduces graphene oxide through heat treatment, removing unstable oxygen-containing functional groups from its surface, reducing steric hindrance and electrostatic repulsion between layers, and allowing for tighter layer stacking. Then, diamines and amino acids are introduced. The amino groups at both ends of the diamine react chemically with carboxyl or epoxy groups on adjacent graphene layers to form covalent bonds, thereby locking the diamine molecules between graphene layers. Amino acids contain both amino and carboxyl groups, and can react with graphene like diamines, while also introducing new specific adsorption sites between layers. The amino groups on amino acids can attack the epoxy groups on graphene, undergoing nucleophilic substitution reactions, thus grafting onto the graphene surface or edges. By synergistically controlling the interlayer spacing of graphene oxide through heat treatment, diamines, and amino acids, graphene oxide can be obtained with properties similar to Sc. 3+ Channels with highly matched particle size trap Sc 3+ At the same time, Sc 3+ As a hard acid ion, the amino / carboxyl group exhibits extremely strong chelating properties, forming stable chelate bonds that strongly adsorb onto the membrane surface, while most impurity ions flow out of the membrane, achieving Sc 3+ The membrane effectively separates from impurity ions, and a small portion of the weakly adsorbed impurity ions on the membrane surface are eluted by the subsequent first rinse.

[0010] Preferably, the solvent includes water.

[0011] Preferably, the mass concentration of the graphene oxide dispersion is 0.5 g / L to 2 g / L, for example: 0.5 g / L, 0.8 g / L, 1 g / L, 1.5 g / L or 2 g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0012] Preferably, the heat treatment temperature is 140℃~170℃, for example: 140℃, 145℃, 150℃, 160℃ or 170℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0013] Preferably, the heat treatment time is 2h to 4h, for example: 2h, 2.5h, 3h, 3.5h or 4h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] Preferably, the diamine monomer includes any one or a combination of at least two of ethylenediamine, hexamethylenediamine, or m-phenylenediamine. Typical but non-limiting combinations include combinations of ethylenediamine and m-phenylenediamine, combinations of ethylenediamine and hexamethylenediamine, or combinations of hexamethylenediamine and m-phenylenediamine.

[0015] Preferably, the mass ratio of graphene oxide to diamine monomer in the pretreated graphene oxide dispersion is 1:(0.1~1), for example: 1:0.1, 1:0.2, 1:0.5, 1:0.8 or 1:1, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] Preferably, the amino acid includes any one or a combination of at least two of serine, alanine, or lysine. Typical but non-limiting combinations include combinations of serine and lysine, serine and alanine, or alanine and lysine.

[0017] Preferably, the mass ratio of graphene oxide to amino acids in the pretreated graphene oxide dispersion is 1:(0.1~0.5), for example: 1:0.1, 1:0.2, 1:0.3, 1:0.4 or 1:0.5, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] Preferably, the pH of the modification reaction is 4.5 to 6, for example: 4.5, 4.8, 5, 5.5 or 6, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the temperature of the modification reaction is 55℃~70℃, for example: 55℃, 58℃, 60℃, 65℃ or 70℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the modification reaction time is 4h to 6h, for example: 4h, 4.5h, 5h, 5.5h or 6h, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0021] Preferably, the vacuum drying temperature is 60℃~80℃, for example: 60℃, 65℃, 70℃, 75℃ or 80℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, the pH of the scandium-containing solution is adjusted to be 2-3, for example: 2, 2.2, 2.5, 2.8 or 3, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, during the adsorption filtration process, the flow rate of the scandium-containing liquid is 1 mL / min to 3 mL / min, for example: 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min or 3 mL / min, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, the pH of the EDTA-containing buffer solution is 4 to 6, for example: 4, 4.5, 5, 5.5 or 6, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, the EDTA-containing buffer solution includes an acetate-sodium acetate buffer solution.

[0026] Preferably, the molar concentration of EDTA in the EDTA-containing buffer solution is 0.05 mol / L to 0.1 mol / L, for example: 0.05 mol / L, 0.06 mol / L, 0.08 mol / L, 0.09 mol / L or 0.1 mol / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, during the first rinsing process, the flow rate of the EDTA-containing buffer solution is 2BV / h to 6BV / h, for example: 2BV / h, 3BV / h, 4BV / h, 5BV / h or 6BV / h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the acid solution includes nitric acid and / or hydrochloric acid.

[0029] Preferably, the molar concentration of the acid solution is 0.1 mol / L to 0.5 mol / L, for example: 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, during the second rinsing process, the flow rate of the acid solution is 3BV / h to 6BV / h, for example: 3BV / h, 3.5BV / h, 4BV / h, 5BV / h or 6BV / h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] Preferably, after the second rinsing, the modified graphene oxide layered film is recycled after being successively subjected to acid washing, first water washing, alkaline washing, and second water washing.

[0032] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0033] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses a modified graphene oxide layered membrane to adsorb and filter scandium-containing liquid, trapping scandium ions and some impurity ions on the membrane surface to achieve preliminary separation of scandium and impurity ions. Then, the modified graphene oxide layered membrane is rinsed with a buffer solution containing EDTA. Since the impurity ions are weakly adsorbed to the membrane, while the scandium ions are strongly adsorbed to the membrane, EDTA can complex and elute the impurity ions. The scandium ions are still adsorbed on the membrane surface. Finally, a high-purity scandium-rich solution can be obtained by rinsing with an acid solution. This solves the problems of difficult separation of scandium and impurity ions, low efficiency of traditional separation, and insufficient selectivity of membrane materials, and greatly improves the recovery rate of scandium and the purity of the recovered scandium material.

[0034] (2) The method for adsorbing and purifying scandium based on graphene oxide layered membrane described in this invention can achieve an iron removal rate of over 87%, an aluminum removal rate of over 85%, and a scandium recovery rate of over 88%. Detailed Implementation

[0035] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0036] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0037] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0038] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art can understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology.

[0039] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined according to its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order in which they are written or in any order that does not conflict with the technology.

[0040] The modified graphene oxide layered films used in the embodiments and comparative examples of this invention were prepared by the following method: Graphene oxide was mixed with deionized water to obtain a 1 g / L graphene oxide dispersion. The graphene oxide dispersion was then heat-treated at 150 °C for 3 h to obtain a pretreated graphene oxide dispersion. The pretreated graphene oxide dispersion, ethylenediamine monomer and lysine were mixed at a mass ratio of 1:0.5:0.3, the pH was adjusted to 5, and the modification reaction was carried out at 65℃ for 5 h to obtain the modified graphene oxide dispersion. The modified graphene oxide dispersion was spin-coated onto the substrate surface and vacuum dried at 70°C to obtain the modified graphene oxide layered film.

[0041] The mass concentrations of various ions in the scandium-containing solutions used in the embodiments and comparative examples of this invention are as follows: Sc 3+ 8g / L, Fe 3+ 300mg / L, Al 3+ 186 mg / L.

[0042] Example 1 This embodiment provides a method for purifying scandium based on the adsorption of graphene oxide layered membranes, the method comprising the following steps: After adjusting the pH of the scandium-containing solution to 2.5, the flow rate of the scandium-containing solution was controlled at 2 mL / min, and the scandium-containing solution was adsorbed and filtered using a modified graphene oxide layered membrane. After a first rinse of the modified graphene oxide layered membrane using an EDTA-sodium acetate buffer solution (pH 5, EDTA molar concentration 0.08 mol / L) at a flow rate of 4 BV / h, a second rinse of the modified graphene oxide layered membrane was performed using a 0.3 mol / L hydrochloric acid solution at a flow rate of 4 BV / h to obtain a scandium-rich solution.

[0043] Example 2 This embodiment provides a method for purifying scandium based on the adsorption of graphene oxide layered membranes, the method comprising the following steps: After adjusting the pH of the scandium-containing solution to 2, the flow rate of the scandium-containing solution was controlled at 1 mL / min, and the scandium-containing solution was adsorbed and filtered using a modified graphene oxide layered membrane. After a first rinse of the modified graphene oxide layered membrane using an EDTA-sodium acetate buffer solution (pH 4, EDTA molar concentration 0.05 mol / L) at a flow rate of 2 BV / h, a second rinse of the modified graphene oxide layered membrane was performed using a 0.1 mol / L hydrochloric acid solution at a flow rate of 3 BV / h to obtain a scandium-rich solution.

[0044] Example 3 This embodiment provides a method for purifying scandium based on the adsorption of graphene oxide layered membranes, the method comprising the following steps: After adjusting the pH of the scandium-containing solution to 3, the flow rate of the scandium-containing solution was controlled at 3 mL / min, and the scandium-containing solution was adsorbed and filtered using a modified graphene oxide layered membrane. The modified graphene oxide layered membrane was first rinsed using an EDTA-sodium acetate buffer solution (pH 6, EDTA molar concentration 0.1 mol / L) at a flow rate of 2 BV / h. Then, the modified graphene oxide layered membrane was rinsed a second time using a 0.5 mol / L nitric acid solution at a flow rate of 6 BV / h to obtain a scandium-rich solution.

[0045] Example 4 The only difference between this embodiment and Embodiment 1 is that, during the adsorption filtration process, the flow rate of the scandium-containing liquid is 0.5 mL / min, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0046] Example 5 The only difference between this embodiment and Embodiment 1 is that, during the adsorption filtration process, the flow rate of the scandium-containing liquid is 5 mL / min, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0047] Example 6 The only difference between this embodiment and Example 1 is that the molar concentration of EDTA in the EDTA-containing buffer is 0.02 mol / L. All other conditions and parameters are exactly the same as in Example 1.

[0048] Example 7 The only difference between this embodiment and Example 1 is that the molar concentration of EDTA in the EDTA-containing buffer is 0.2 mol / L. All other conditions and parameters are exactly the same as in Example 1.

[0049] Example 8 The only difference between this embodiment and Embodiment 1 is that, during the first rinsing process, the flow rate of the EDTA-containing buffer solution is 1 BV / h, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0050] Example 9 The only difference between this embodiment and Embodiment 1 is that during the first rinsing process, the flow rate of the EDTA-containing buffer solution is 8 BV / h, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0051] Comparative Example 1 The only difference between this comparative example and Example 1 is that an unmodified graphene oxide layered film is used; all other conditions and parameters are exactly the same as in Example 1.

[0052] Comparative Example 2 The only difference between this comparative example and Example 1 is that the EDTA-containing buffer solution is replaced with an EDTA aqueous solution; all other conditions and parameters are exactly the same as in Example 1.

[0053] Performance testing: The volumes of the untreated and post-treated scandium-rich solutions were weighed, and samples were sent for testing. The removal rates of each impurity element and the scandium recovery rate were calculated. The results are shown in Table 1. Table 1 As can be seen from Table 1, and from Examples 1 to 9, the method for purifying scandium based on graphene oxide layered membrane adsorption of the present invention can achieve an iron removal rate of over 79%, an aluminum removal rate of over 79%, and a scandium recovery rate of over 82%. By adjusting the conditions, the iron removal rate can reach over 87%, the aluminum removal rate can reach over 85%, and the scandium recovery rate can reach over 88%.

[0054] A comparison of Examples 1 and 4-5 shows that in the method for purifying scandium based on graphene oxide layered membrane adsorption according to the present invention, the flow rate of the scandium-containing solution during the adsorption and filtration process affects the purification effect. Controlling the flow rate of the scandium-containing solution to 1 mL / min to 3 mL / min results in a better purification effect. If the flow rate of the scandium-containing solution is too high, the residence time of the solution on the membrane surface and in the layered pores is shortened, the scandium adsorption effect decreases, and the scandium recovery rate decreases. If the flow rate of the scandium-containing solution is too low, prolonged static contact can easily cause the continuous accumulation and adsorption of impurity ions, increasing the subsequent impurity removal load and potentially causing slight scaling and pore blockage on the membrane surface.

[0055] A comparison of Examples 1 and 6-7 shows that in the method for purifying scandium based on graphene oxide layered membrane adsorption described in this invention, the molar concentration of EDTA in the EDTA-containing buffer solution affects the purification effect. Controlling the molar concentration of EDTA in the EDTA-containing buffer solution to 0.05 mol / L~0.1 mol / L results in better purification. If the molar concentration of EDTA in the EDTA-containing buffer solution is too high, excessive free EDTA molecules will enhance the complexation competition ability of the system under pH buffer conditions, partially depleting the membrane and Scandium. 3+The chelation sites between them cause scandium to desorb and be lost prematurely, resulting in a decrease in scandium recovery. If the molar concentration of EDTA in the buffer containing EDTA is too low, it cannot completely complex the weakly adsorbed impurity ions on the membrane surface, and the impurities are not completely eluted.

[0056] A comparison of Examples 1 and 8-9 shows that in the method for purifying scandium based on graphene oxide layered membrane adsorption according to the present invention, the flow rate of the EDTA-containing buffer solution during the first rinsing process affects the purification effect. Controlling the flow rate of the EDTA-containing buffer solution to 2 BV / h~6 BV / h during the first rinsing process yields better purification results. If the flow rate of the EDTA-containing buffer solution is too fast, the buffer solution flows through the membrane layer for a short time, resulting in insufficient contact and complexation reaction between EDTA and the impurity ions adsorbed on the membrane, leading to incomplete impurity elution. If the flow rate of the EDTA-containing buffer solution is too slow, the liquid flow remains in the membrane pores for a long time, and excessive EDTA continues to contact the membrane, increasing the Sc... 3+ The risk of complexation and elution leads to scandium loss.

[0057] A comparison of Example 1 and Comparative Example 1 shows that the modified graphene oxide layered film of the present invention, which uses heat treatment, diamine, and amino acids to synergistically regulate the interlayer spacing, can obtain a film similar to Sc 3+ Channels with highly matched particle size trap Sc 3+ Simultaneously, impurity ions flow out of the membrane, achieving Sc 3+ The high efficiency of separation from impurity ions is hampered by the uncontrollable interlayer spacing of the unmodified graphene oxide film, severe co-adsorption of impurities, and significantly low product purity and scandium recovery rate.

[0058] Comparing Example 1 and Comparative Example 2, it can be seen that the present invention uses a buffer solution containing EDTA to perform the first rinse of the modified graphene oxide layered membrane. This allows for control of the rinsing solution to remain stable at a suitable pH. EDTA preferentially and precisely complexes impurity ions, while having difficulty competing with strongly chelated Sc on the membrane. 3+ Pure EDTA aqueous solution has no buffering capacity. The dissociation of EDTA and the complexation of metal ions will continuously change the pH of the system. When the pH deviates from the optimal range, it will not only significantly reduce the complexation capacity for impurity ions and reduce the impurity removal effect, but it will also complex Sc. 3+ This reduces scandium recovery rate.

[0059] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for adsorbing and purifying scandium based on graphene oxide layered membrane, characterized in that, The method includes the following steps: Provides modified graphene oxide layered films and scandium-containing solutions; After adjusting the pH of the scandium-containing solution, the solution was adsorbed and filtered using a modified graphene oxide layered membrane. After a first rinse with a buffer solution containing EDTA, the modified graphene oxide layered membrane was rinsed a second time with an acid solution to obtain a scandium-rich solution.

2. The method as described in claim 1, characterized in that, The modified graphene oxide layered film was prepared by the following method: Graphene oxide is mixed with a solvent to obtain a graphene oxide dispersion, and the graphene oxide dispersion is heat-treated to obtain a pretreated graphene oxide dispersion. The pretreated graphene oxide dispersion, diamine monomer, and amino acid were mixed and modified to obtain a modified graphene oxide dispersion. The modified graphene oxide dispersion was coated onto the substrate surface and then vacuum dried to obtain the modified graphene oxide layered film.

3. The method as described in claim 2, characterized in that, The solvent includes water; Preferably, the mass concentration of the graphene oxide dispersion is 0.5 g / L to 2 g / L; Preferably, the heat treatment temperature is 140℃~170℃; Preferably, the heat treatment time is 2h to 4h.

4. The method as described in claim 2 or 3, characterized in that, The diamine monomer includes any one or a combination of at least two of ethylenediamine, hexamethylenediamine, or m-phenylenediamine; Preferably, the mass ratio of graphene oxide to diamine monomer in the pretreated graphene oxide dispersion is 1:(0.1~1); Preferably, the amino acid includes any one or a combination of at least two of serine, alanine, or lysine; Preferably, the mass ratio of graphene oxide to amino acids in the pretreated graphene oxide dispersion is 1:(0.1~0.5); Preferably, the pH of the modification reaction is 4.5-6; Preferably, the temperature of the modification reaction is 55℃~70℃; Preferably, the modification reaction takes 4 to 6 hours. Preferably, the vacuum drying temperature is 60℃~80℃.

5. The method according to any one of claims 1-4, characterized in that, The pH of the scandium-containing solution is adjusted to 2-3.

6. The method according to any one of claims 1-5, characterized in that, During the adsorption filtration process, the flow rate of the scandium-containing liquid is 1 mL / min to 3 mL / min.

7. The method according to any one of claims 1-6, characterized in that, The pH of the EDTA-containing buffer solution is 4-6; Preferably, the EDTA-containing buffer solution includes an acetate-sodium acetate buffer solution; Preferably, the molar concentration of EDTA in the EDTA-containing buffer solution is 0.05 mol / L to 0.1 mol / L.

8. The method according to any one of claims 1-7, characterized in that, During the first rinsing process, the flow rate of the EDTA-containing buffer solution is 2 BV / h to 6 BV / h.

9. The method according to any one of claims 1-8, characterized in that, The acid solution includes nitric acid and / or hydrochloric acid; Preferably, the molar concentration of the acid solution is 0.1 mol / L to 0.5 mol / L.

10. The method according to any one of claims 1-9, characterized in that, During the second rinsing process, the flow rate of the acid solution is 3 BV / h to 6 BV / h.

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