A method for separating and extracting indium from a solution using transferrin

Abstract

The present invention belongs to the technical field of metal smelting, and specifically relates to a method for separating and extracting indium from a solution using transferrin, comprising the following steps: a first step: removing metal ions from transferrin to obtain transferrin at a blank site; a second step: mixing transferrin with sodium alginate and glutaraldehyde to obtain transferrin gel balls; a third step: adding the obtained transferrin gel balls to an adsorption column to obtain a transferrin gel ball adsorption column; a fourth step: putting an indium-containing solution into the transferrin gel ball adsorption column obtained in the third step, controlling the flow rate to adsorb the transferrin gel balls, and obtaining indium-rich protein gel balls. The present invention can achieve a recovery rate of indium of more than 95%, and immobilized transferrin as an adsorbent can perform high-precision separation and extraction for low-concentration indium, improve resource utilization efficiency, reduce the use of chemical agents, and avoid the generation of waste and harmful substances.

Description

Technical Field

[0001] The invention belongs to the technical field of metal smelting, and in particular relates to a method for separating and extracting indium from a solution by utilizing transferrin. Background Art

[0002] With the continuous progress of science and technology and industry, the status of strategic metals has become increasingly prominent around the world. Among them, indium, as an important strategic metal, has attracted much attention due to its wide application in the field of advanced technology. Indium is used in the semiconductor industry to manufacture thin-film transistors and liquid crystal displays, and is also used in solar cells, optical fiber communications and other fields.

[0003] However, the scarcity and high value of indium make its supply and sustainable use one of the important issues in current research and industrial development. There are no independent indium deposits in nature. Indium usually exists in zinc sulfide ores in an associated form. Currently, in industrial production, solvent extraction, electrochemical precipitation and other methods are usually used to recover indium from hydrometallurgical zinc smelting waste slag.

[0004] For example, the Chinese patent with publication number CN113122736A proposes a method for efficiently separating and extracting metallic indium from an acidic solution, which can achieve efficient stripping of an indium-rich organic phase or obtain high-purity metallic indium by constant potential electrodeposition. The above process is not affected by Fe3+, Zn2+ ions, etc., thereby achieving separation and extraction of indium;

[0005] However, this method has high requirements for the extractant and is dangerous, and cannot meet the process requirements for sustainable development.

[0006] Another example is a Chinese patent with publication number CN112646985A, which proposes a method for enriching and purifying metallic indium in ITO thin film etching waste liquid, which greatly improves the concentration of indium in the aqueous phase and ultimately achieves the separation of indium from other metal ions such as tin, molybdenum, and aluminum, providing a guarantee for subsequent electrolytic refining, and the recovery rate of indium can reach more than 90%;

[0007] However, this extraction method consumes chemical reagents and may cause harm to the environment, so it is not suitable for industrial production.

[0008] In summary, the above-mentioned patents all have some limitations in the recovery methods, including low extraction accuracy and waste of resources. Not only is the extraction effect in ores with low indium content poor, but a large amount of waste and environmental emissions will be generated, which will have a negative impact on the environment. Therefore, it is necessary to develop a green and environmentally friendly extraction method based on biotechnology to efficiently enrich and recycle indium. Summary of the invention

[0009] The purpose of the present invention is to provide a method for separating and extracting indium from a solution by using transferrin, which can achieve an indium recovery rate of more than 95%. The immobilized transferrin as an adsorbent can perform high-precision separation and extraction of low-concentration indium, improve resource utilization efficiency, reduce the use of chemical agents, avoid the generation of waste and harmful substances, and have less negative impact on the environment.

[0010] The technical solution adopted by the present invention is as follows:

[0011] A method for separating and extracting indium from a solution using transferrin comprises the following steps:

[0012] The first step: removing metal ions from transferrin to obtain transferrin with blank sites;

[0013] Step 2: Mixing transferrin with sodium alginate and glutaraldehyde to obtain transferrin gel spheres;

[0014] Step 3: adding the prepared transferrin gel beads into an adsorption column to obtain a transferrin gel bead adsorption column;

[0015] Step 4: putting the indium-containing solution into the transferrin gel ball adsorption column prepared in the third step, controlling the flow rate to adsorb the transferrin gel ball to obtain indium-rich protein gel balls;

[0016] Step 5: Add HCl solution to the indium-rich protein gel balls obtained in step 4, control the elution rate, so that the indium ions on the protein are desorbed and flow out, and collect the effluent obtained as the target purified indium solution, and the remaining material is the protein gel balls;

[0017] Step 6: The remaining protein gel balls in step 5 are washed several times with distilled water and dried so that transferrin can be used in the next round of extraction.

[0018] The transferrin in the first step is in a completely deironized state and is dissolved in 50 mM HEPES buffer at a pH of 7.4.

[0019] In the second step, a mixed solution of sodium alginate with a mass concentration of 1-3% and the above transferrin is dripped dropwise into a CaCl2 solution, washed and dried, and placed at 4°C to harden for 1 hour.

[0020] In the second step, 1-5% glutaraldehyde is added to the obtained gel spheres at a mass ratio of 1:10 for covalent bonding at 5-30°C for at least 10 hours to remove ions on the surface of the gel, and the water is absorbed and stored at 4°C for later use.

[0021] The inner diameter of the adsorption column in the third step is 15 mm and the effective height is 200 mm.

[0022] The flow rate controlled in the fourth step is 1 mL / min and the temperature is 27±1°C.

[0023] In the fifth step, the pH of the HCl solution is 2-3, and the desorption temperature is 30°C.

[0024] The technical effects achieved by the present invention are:

[0025] In the whole process of the present invention, the recovery rate of indium reaches more than 95%. The immobilized transferrin as an adsorbent can perform high-precision separation and extraction of low-concentration indium, which is expected to solve the problem of poor extraction effect of traditional methods in low-content enrichment liquid and improve resource utilization efficiency.

[0026] The transferrin method of the present invention adopts biological extraction, reduces the use of chemical agents, avoids the generation of waste and harmful substances, and has less negative impact on the environment. Since the transferrin method follows the biological cycle principle, its extraction process has high sustainable development. The biological method can not only effectively extract indium, but also avoid over-exploitation of mineral resources, which is conducive to the long-term sustainable utilization of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the method for separating and extracting indium from a solution of the present invention;

[0028] Figure 2 is a schematic diagram of a transferrin adsorption column in the present invention;

[0029] Figure 3 The present invention is a schematic diagram of the use of a device for separating indium from a mixed solution using a transferrin adsorption column. DETAILED DESCRIPTION

[0030] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

[0031] like Figure 1-3 As shown, a method for separating and extracting indium from a solution using transferrin comprises the following steps:

[0032] Step 1: prepare transferrin. Transferrin is a protein that can bind to metal ions and can be extracted from human or bovine serum. The transferrin used in this method is in a completely deironized state, i.e., transferrin without blank sites that bind to any metal ions.

[0033] In order to prepare completely deironified transferrin, the transferrin available in the laboratory needs to be incubated in a 1mM EDTA 3% (v / v) acetic acid solution for 5-10 minutes, and then dialyzed in a HEPES (pH 7.4, 50mM) buffer at 4°C for 24 hours to remove the metal ions on the transferrin. The dialyzed transferrin solution is a completely deironified transferrin solution, which can be used in subsequent steps;

[0034] Among them, EDTA is a compound that can form complexes with a variety of metal ions and can effectively remove the metal ions that have been bound to transferrin; and HEPES is a commonly used buffer that can maintain the pH value of the solution unchanged during the dialysis process.

[0035] Step 2: Immobilize transferrin. In order to improve the stability and reusability of transferrin, it needs to be immobilized on a carrier. The carrier used in this method is sodium alginate gel spheres.

[0036] Among them, sodium alginate is a natural polysaccharide with good biocompatibility and biodegradability;

[0037] In order to prepare immobilized transferrin, a sodium alginate solution with a mass concentration of 1-3% is mixed with the above transferrin solution in proportion, and then a CaCl2 solution is dropped into the mixed solution and stirred at a certain speed to obtain smooth small balls with a diameter of 2-3 mm;

[0038] Moreover, CaCl2 is a compound that can form cross-links with sodium alginate, which can solidify the sodium alginate solution into a spherical shape;

[0039] Wash, dry and place at 4°C for 1 hour to harden, add 1-5% glutaraldehyde to the obtained gel balls at a mass ratio of 1:10 at 5-30°C for covalent bonding, react overnight, which is at least 10 hours, wash with deionized water to remove ions on the surface of the gel, filter to remove surface moisture, and then use filter paper to absorb moisture, and place at 4°C for use;

[0040] Among them, glutaraldehyde is a compound that can react with amino groups to form imino bonds, which can firmly combine transferrin and sodium alginate gel beads. The immobilized transferrin is immobilized transferrin.

[0041] Step 3: Adsorption of the indium-containing solution. In order to separate and extract indium ions from the indium-containing solution, the indium-containing solution needs to be passed through an immobilized transferrin adsorption column;

[0042] The adsorption column used in the method is a column with an inner diameter of 15 mm and an effective height of 200 mm, and the interior is filled with the above-mentioned immobilized transferrin gel spheres;

[0043] The indium-containing solution can be extracted from low-concentration sources such as indium-containing smelting slag and electronic waste, and its indium concentration is generally between 10-100 mg / L;

[0044] Inject the indium-containing solution into the adsorption column at a flow rate of 1 mL / min at a temperature of 27±1°C, so that it is fully in contact with the immobilized transferrin gel beads. The blank sites on the transferrin will combine with the indium ions in the solution, thereby achieving the adsorption of indium ions.

[0045] The effluent is collected and the residual indium concentration is measured. By comparing it with the indium concentration of the indium-containing solution entering the adsorption column, the adsorption efficiency and adsorption amount can be obtained.

[0046] Step 4: eluting the indium-rich protein. In order to recover indium ions from the immobilized transferrin, it is necessary to elute them. The eluent used in this method is an HCl solution with a pH of 2-3, which can react with the indium ions on the transferrin. The reaction temperature is 30°C, so that the indium ions on the protein are desorbed and flow out. The collected effluent is the target purified indium solution. At this time, the indium concentration in the target purified indium solution is significantly increased, while the indium content on the immobilized transferrin gel balls is significantly reduced.

[0047] In order to evaluate the extraction and purification effects of the method on indium, the target purified indium solution needs to be analyzed. The analysis method used in the method is atomic absorption spectrometry (AAS), which can determine the purity and impurity content of indium in the solution. The target purified indium solution is measured using an AAS instrument to obtain the mass concentration of indium and the types and contents of impurity elements.

[0048] Based on the AAS results, it can be determined whether the present method can effectively recover high-purity indium from low-concentration sources and whether further refining treatment is required.

[0049] In order to achieve the reuse of transferrin, the eluted immobilized transferrin needs to be regenerated. The regeneration treatment used in this method is to wash it with distilled water several times and dry it to restore the transferrin to the state of the blank site. The eluted immobilized transferrin gel balls are washed with distilled water several times and dried to remove the residual HCl solution and impurities, so that the metal ion binding sites on the transferrin are free again. The dried immobilized transferrin gel balls are reloaded into the adsorption column and can be used for the next round of separation and extraction of indium-containing solution.

[0050] Unless otherwise specified, the instruments, reagents, processes, parameters, etc. involved in this application are conventional instruments, reagents, parameters, etc. and are not given as examples here.

[0051] The transferrin adsorption column in this embodiment realizes the separation of indium ions from the simulated mixed solution, but it is only a part of the embodiments of the present invention, not all of the embodiments. Any changes, improvements or substitutions made within the spirit and principles of the present invention should be considered to be included in the scope of protection of the present invention.

[0052] The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A method for separating and extracting indium from a solution using transferrin, characterized in that: The following steps are involved: S1: removing metal ions from transferrin to obtain transferrin with blank sites; S2: Mixing transferrin with sodium alginate and glutaraldehyde to obtain transferrin gel spheres; S3: adding the prepared transferrin gel beads to an adsorption column to obtain a transferrin gel bead adsorption column; S4: putting the indium-containing solution into the transferrin gel ball adsorption column prepared in S3, controlling the flow rate to adsorb the transferrin gel balls, and obtaining indium-rich protein gel balls; S5: adding HCl solution to the indium-rich protein gel balls obtained in S4, controlling the elution rate so that the indium ions on the protein are desorbed and flow out, collecting the resulting effluent as the target purified indium solution, and the remaining material as the protein gel balls; S6: The remaining protein gel balls in S5 are washed several times with distilled water and dried so that the transferrin can be used in the next round of extraction.

2. A method for separating and extracting indium from a solution using transferrin according to claim 1, characterized in that: The transferrin in the S1 is in a completely deironified state and is dissolved in a 50 mM HEPES buffer with a pH of 7.

4.

3. A method for separating and extracting indium from a solution using transferrin according to claim 1, characterized in that: In the S2, a mixed solution of sodium alginate with a mass concentration of 1-3% and the above transferrin is dripped dropwise into a CaCl2 solution, washed and dried, and placed at 4°C to harden for 1 hour.

4. A method for separating and extracting indium from a solution using transferrin according to claim 1, characterized in that: In S2, 1-5% glutaraldehyde is added to the obtained gel spheres at a mass ratio of 1:10 for covalent bonding at 5-30°C for at least 10 hours to remove ions on the surface of the gel, and the water is absorbed and stored at 4°C for later use.

5. The method for separating and extracting indium from a solution using transferrin according to claim 1, characterized in that: The adsorption column in S3 has an inner diameter of 15 mm and a height of 200 mm.

6. The method for separating and extracting indium from a solution using transferrin according to claim 1, characterized in that: The flow rate controlled in S4 is 1 mL / min and the temperature is 27±1°C.

7. The method for separating and extracting indium from a solution using transferrin according to claim 1, characterized in that: The pH of the HCl solution in S5 is 2-3, and the desorption temperature is 30°C.

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