A metal extractant microcapsule and its preparation method

Abstract

The present invention relates to the field of preparation of metal extractants, and particularly to a metal extractant microcapsule and a preparation method thereof. The preparation method of the metal extractant microcapsule in the present invention comprises the following preparation steps: (1) Ethyl acrylate, methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid sodium salt, a crosslinking agent, and an initiator are mixed evenly, and an emulsifier solution is added dropwise under stirring conditions, followed by ultrasonic treatment. After irradiating with ultraviolet light for 10-20 min under stirring conditions, it is washed with pure water, separated, and dried to obtain hollow microcapsules; (2) The hollow microcapsules obtained in step (1) are evacuated, a metal chelating agent is added, and ultrasonic treatment is carried out for 5-10 h, followed by filtration and washing to obtain metal extractant microcapsules. The preparation process of the metal extractant microcapsule is simple and easy to operate, has a good encapsulation rate for the metal chelating agent, and has a high removal effect on various metal ions.

Description

Technical Field

[0001] The present invention relates to the field of preparation of metal extractants, and particularly to a metal extractant microcapsule and a preparation method thereof. Background Art

[0002] Sputtering targets have a wide range of applications, mainly in the electronics and information industries, such as integrated circuits, information storage, liquid crystal displays, laser memories, electronic control devices, etc. They can also be used in the field of glass coating, and can also be applied to industries such as wear-resistant materials, high-temperature corrosion resistance, and high-grade decorative articles. High chemical purity is the basis of the quality of sputtering targets, which has a direct impact on the composition and performance of sputtered film layers. High-purity sputtering targets can significantly reduce the influence of impurities on the film layer and ensure that the film layer has excellent physical and chemical properties. This requires that the metal solution used to make sputtering targets also has a high purity, so it is necessary to purify the metal solution to meet the requirements of sputtering targets.

[0003] During the purification process of metal nickel solution, there are often many impurity ions, such as magnesium ions, copper ions, lead ions, manganese ions, and iron ions. Generally, the extraction method is used to remove impurity ions. However, in the extraction process, ordinary extractants have different adsorption effects on different metal ions, and the compounds formed by them and impurity ions have unstable properties, resulting in an increase in the number of extraction stages, which will make the process in the purification process more complex and the production cost higher. Patent CN114045394 A discloses a method for separating copper in nickel chloride solution by extraction. In this invention, the organic phase composed of Lix984 and sulfonated kerosene is continuously countercurrently extracted with nickel chloride solution in the extraction section. The high-copper organic phase loaded with nickel and cobalt after extraction is continuously countercurrently stripped with nickel and cobalt washing acid, and then continuously countercurrently stripped with copper washing acid, and then reused to the extraction section. Although the copper removal effect in this invention is good and no other impurities are introduced, there is a lack of data on the removal effect of manganese ions, chromium ions, and magnesium ions. Therefore, the extraction method used in the purification process of the metal solution for sputtering targets still needs to be improved.

[0004] Based on the problems existing in the prior art, it is of great significance to develop a metal extractant that has a good removal effect on different types of metal ions under process condition control, both for scientific and technological development and actual industrial production. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a metal extractant microcapsule and a preparation method thereof. The preparation process of the metal extractant microcapsule is simple and easy to operate, has a good encapsulation rate for metal chelating agents, and has a high removal effect on a variety of metal ions.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect of the present invention, a method for preparing metal extractant microcapsules is provided, including the following preparation steps:

[0008] (1) Ethyl acrylate, methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid sodium salt, a crosslinking agent, and an initiator are mixed evenly, and an emulsifier solution is added dropwise under stirring conditions, followed by ultrasonic treatment. After irradiating with ultraviolet light for 10 - 20 min under stirring conditions, it is washed with pure water, separated, and dried to obtain hollow microcapsules;

[0009] (2) The hollow microcapsules obtained in step (1) are evacuated, a metal chelating agent is added, and ultrasonic treatment is carried out for 5 - 10 h, followed by filtration and washing to obtain metal extractant microcapsules.

[0010] In some embodiments, the molar ratio of ethyl acrylate, methacrylamide, and 2-acrylamido-2-methylpropanesulfonic acid sodium salt is 1:(1.5 - 2.5):(1.5 - 2).

[0011] Preferably, the molar ratio of ethyl acrylate, methacrylamide, and 2-acrylamido-2-methylpropanesulfonic acid sodium salt is 1:2:1.75.

[0012] In some embodiments, the crosslinking agent includes 1,4-butanediol dimethacrylate and hexanediol dimethacrylate with a mass ratio of (25 - 30):1.

[0013] Preferably, the crosslinking agent includes 1,4-butanediol dimethacrylate and hexanediol dimethacrylate with a mass ratio of 28:1.

[0014] In some embodiments, the usage amount of the crosslinking agent is 15 - 20% of the total mass of ethyl acrylate, methacrylamide, and 2-acrylamido-2-methylpropanesulfonic acid sodium salt.

[0015] Preferably, the usage amount of the crosslinking agent is 17% of the total mass of ethyl acrylate, methacrylamide, and 2-acrylamido-2-methylpropanesulfonic acid sodium salt.

[0016] In some embodiments, the initiator is one or more of benzoin and its derivatives, acetophenones, aromatic ketones, and acylphosphine oxides.

[0017] Preferably, the initiator is one or more of benzoin and its derivatives, acetophenones, and aromatic ketones.

[0018] In some embodiments, the emulsifier in the emulsifier solution is one or more of sodium ethylenediamine ethanesulfonate, sodium dodecyl diphenyl ether disulfonate, and dodecylbenzenesulfonate; the mass concentration of the emulsifier solution is 2 - 4.5 wt%.

[0019] Preferably, the emulsifier in the emulsifier solution is sodium ethylenediamine ethanesulfonate and sodium dodecyl diphenyl ether disulfonate; the mass concentration of the emulsifier solution is 3.5 wt%.

[0020] In some embodiments, the usage amount of the emulsifier is 16-18% of the total mass of ethyl acrylate, methacrylamide, and sodium 2-acrylamido-2-methylpropanesulfonate.

[0021] Preferably, the usage amount of the emulsifier is 17% of the total mass of ethyl acrylate, methacrylamide, and sodium 2-acrylamido-2-methylpropanesulfonate.

[0022] In some embodiments, the mass ratio of the hollow microcapsules in step (2) to the metal chelating agent is (1.6-2.3):1.

[0023] Preferably, the mass ratio of the hollow microcapsules in step (2) to the metal chelating agent is 1.95:1.

[0024] In some embodiments, the structural formula of the metal chelating agent is:

[0025]

[0026] In some embodiments, the preparation method of the metal chelating agent includes the following preparation steps:

[0027] (1) Dissolve dibutanolamine in absolute ethanol, add carbon disulfide, react for 5-8 h under a nitrogen atmosphere at 0-5 °C, then adjust the pH to neutral with an aqueous sodium hydroxide solution, and perform rotary evaporation to obtain sodium bis(4-hydroxybutyl) dithiocarbamate;

[0028] (2) Add 4-[bis(β-chloroethyl)amino]benzaldehyde, the sodium bis(4-hydroxybutyl) dithiocarbamate obtained in step (1), and a catalyst to absolute ethanol, heat under reflux, then remove absolute ethanol under reduced pressure, add the obtained solid to pure water and stir, extract and combine the organic phases, dry the water in the organic phase, then concentrate, let stand for 10-20 h, and separate to obtain the metal chelating agent.

[0029] The second aspect of the present invention provides a metal extraction agent microcapsule prepared by the above-mentioned preparation method.

[0030] Through process control, the present invention uses ethyl acrylate, methacrylamide, and sodium 2-acrylamido-2-methylpropanesulfonate as raw materials, makes them polymerize to form hollow microcapsules, and then ultrasonically loads the metal chelating agent into the hollow structure of the microcapsules to obtain metal extraction agent microcapsules with a high encapsulation rate and high adsorption performance for various metal ions.

[0031] The applicant found that by selecting ethyl acrylate, methacrylamide, and sodium 2-acrylamido-2-methylpropanesulfonate as polymerization monomers, under the action of a photoinitiator and a specific emulsifier, and by controlling the molar ratio of the polymerization monomers, the dosages of the initiator and the emulsifier, it was possible to successfully prepare metal extractant microcapsules with a high encapsulation rate for metal chelating agents. Under the condition of the same usage amount, the metal extractant microcapsules had a stronger adsorption capacity for different metal ions than the metal chelating agent, greatly reducing the production cost and improving the resource utilization rate. Among them, the acrylamide group in sodium 2-acrylamido-2-methylpropanesulfonate would accelerate the polymerization reaction; the two side methyl groups and sodium methylsulfonate were combined behind the amino group, which could inhibit the hydrolysis and thermal degradation of the microcapsules; the sulfonated group could make the monomer exhibit high hydrophilicity and ionic characteristics under any pH condition. Moreover, the use of sodium 2-acrylamido-2-methylpropanesulfonate could also reduce the usage amount of the emulsifier and improve the water resistance and thermal stability of the microcapsules.

[0032] The metal chelating agent used in the present invention had good dispersibility and solubility in various solvents and coordinated and chelated with heavy metal ions through nitrogen, oxygen, and sulfur atoms to form stable metal chelates. On the one hand, this metal chelating agent contained more hydroxyl groups, which could improve the performance of the metal chelating agent to a certain extent; on the other hand, the hydroxybutyl group in the structure could also increase the electron density on the surface of the chelating agent molecule and enhance the bonding strength between atoms within the chelating agent molecule. Moreover, the hydroxybutyl groups in the chelating agent were symmetrically distributed, and the symmetry of the chelating agent molecule was relatively high, making it easier to combine with metal ions to form symmetric chelate rings and improving the stability of the chelates.

[0033] In addition, during the process of loading the metal chelating agent into the hollow microcapsules, ultrasound was used to make the metal chelating agent more evenly dispersed in the hollow microcapsules. On the one hand, the hydroxyl groups in the metal chelating agent could form hydrogen bonds with the amide groups on methacrylamide and sodium 2-acrylamido-2-methylpropanesulfonate in the wall material, making the interaction force between the two more firm and improving the adhesion of the metal chelating agent to the microcapsules; on the other hand, the hydroxyl groups could also generate intermolecular electrostatic interactions with the sulfonic acid groups on sodium 2-acrylamido-2-methylpropanesulfonate, further improving the stability of the metal extractant microcapsules. The emulsifiers in the present invention were preferably sodium N-(2-aminoethyl)-2-aminoethanesulfonate and sodium dodecyl diphenyl ether disulfonate. When used in combination, they not only had good emulsifying effects, water resistance, and compatibility with the raw materials used in this system, but also could promote the formation of microcapsules, improve the particle size uniformity and stability of the hollow microcapsules, and thus improve the stability of the metal extractant microcapsules.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1. Through process control, the present invention uses ethyl acrylate, methacrylamide, and sodium 2-acrylamido-2-methylpropanesulfonate as raw materials, causing them to polymerize to form hollow microcapsules. Then, a metal chelating agent is loaded into the hollow structure of the microcapsules by ultrasonic treatment, obtaining metal extraction agent microcapsules with a high encapsulation rate and high adsorption performance for various metal ions. This greatly reduces the production cost and improves the resource utilization rate.

[0036] 2. During the process of loading the metal chelating agent into the hollow microcapsules of the present invention, the hydroxyl groups in the metal chelating agent can form hydrogen bonds with the amide groups on methacrylamide and sodium 2-acrylamido-2-methylpropanesulfonate in the wall material, making the interaction force between the two stronger. It can also generate intermolecular electrostatic interaction with the sulfonic acid group, making the metal extraction agent microcapsules have good stability.

[0037] 3. The metal chelating agent used in the present invention has good dispersibility and solubility in various solvents, can coordinate and chelate with heavy metal ions through nitrogen, oxygen, and sulfur atoms, has high adsorption performance, and the formed metal chelate has strong stability. Detailed Embodiments

[0038] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value within the stated range and any other stated value or intermediate value within the stated range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0039] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention description, which are obvious to those skilled in the art. Other embodiments obtained from the description of the present invention are obvious to those skilled in the art. The description and examples of the present application are only exemplary.

[0040] Regarding the use of "comprising", "including", "having", or "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0041] The catalyst used in Preparation Example 1 of the present invention is potassium iodide, the extraction agent used is dichloromethane; the initiator used is photosensitizer 651.

[0042] Preparation Example 1

[0043] The preparation method of the metal chelating agent used in the examples and comparative examples includes the following preparation steps:

[0044] (1) Dissolve 1 mol of dibutanolamine in 500 mL of absolute ethanol, add 1.1 mol of carbon disulfide, react for 6 h under a nitrogen atmosphere at 0 °C, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and perform rotary evaporation to obtain sodium bis(4-hydroxybutyl)dithiocarbamate;

[0045] (2) Add 0.1 mol of 4-[bis(β-chloroethyl)amino]benzaldehyde, 0.235 mol of sodium bis(4-hydroxybutyl)dithiocarbamate obtained in step (1), and 4.19 mmol of catalyst to 500 mL of absolute ethanol, heat under reflux at 90 °C for 25 h, then remove the absolute ethanol under reduced pressure. Add the obtained solid to 500 mL of pure water and stir. Then extract 3 times with 250 mL of extraction agent each time, combine the organic phases, add 15 g of sodium sulfate to dry the water in the organic phase, concentrate to 50 mL, let stand for 20 h, and filter to obtain the metal chelating agent.

[0046] Preparation Example 2

[0047] Preparation steps of the crosslinking agent:

[0048] Take 1,4-butanediol dimethacrylate and hexanediol dimethacrylate with a mass ratio of 28:1 and mix them evenly to obtain the crosslinking agent.

[0049] Preparation Example 3

[0050] Preparation steps of the crosslinking agent:

[0051] Take 1,4-butanediol dimethacrylate and hexanediol dimethacrylate with a mass ratio of 20:1 and mix them evenly to obtain the crosslinking agent.

[0052] Preparation Example 4

[0053] Preparation steps of the crosslinking agent:

[0054] Take 1,4-butanediol dimethacrylate and hexanediol dimethacrylate with a mass ratio of 35:1 and mix them evenly to obtain the crosslinking agent.

[0055] Preparation Example 5

[0056] Preparation steps of the emulsifier solution:

[0057] Take 2 g of sodium ethylenediamine ethyl sulfonate and 1.5 g of dodecyl diphenyl ether disulfonate and dissolve them in 100 g of pure water to obtain the emulsifier solution.

[0058] Preparation Example 6

[0059] Preparation steps of the emulsifier solution:

[0060] Take 3.5 g of sodium dodecylbenzenesulfonate and dissolve it in 100 g of pure water to obtain the emulsifier solution.

[0061] Example 1

[0062] A preparation method of metal extractant microcapsules, comprising the following preparation steps:

[0063] (1) Mix 0.1 mol of ethyl acrylate, 0.15 mol of methacrylamide, 0.15 mol of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 8.57 g of crosslinking agent, and 2.56 g of initiator evenly. Under the stirring condition of 150 r / min, dropwise add 261 mL of the emulsifier solution, ultrasonicate for 15 min at 40 KHz, under the stirring condition of 150 r / min, irradiate with a 2000 W ultraviolet lamp at a distance of 10 cm for 10 min, then wash 3 times with pure water, filter, and vacuum dry to obtain hollow microcapsules;

[0064] (2) Evacuate 32 g of the hollow microcapsules obtained in step (1), add 20 g of metal chelating agent, ultrasonically treat for 5 h at 20 KHz, filter, and wash 3 times with pure water to obtain metal extractant microcapsules.

[0065] The crosslinking agent used is obtained from Preparation Example 2; the emulsifier solution used is obtained from Preparation Example 5.

[0066] Example 2

[0067] A preparation method of metal extractant microcapsules, comprising the following preparation steps:

[0068] (1) Mix 0.1 mol of ethyl acrylate, 0.25 mol of methacrylamide, 0.2 mol of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 15.41 g of crosslinking agent, and 3.52 g of initiator evenly. Under the stirring condition of 150 r / min, dropwise add 396 mL of the emulsifier solution, ultrasonicate for 15 min at 40 KHz, under the stirring condition of 150 r / min, irradiate with a 2000 W ultraviolet lamp at a distance of 20 cm for 10 min, then wash 3 times with pure water, filter, and vacuum dry to obtain hollow microcapsules;

[0069] (2) Evacuate 46 g of the hollow microcapsules obtained in step (1), add 20 g of the metal chelating agent, ultrasonically treat for 10 h at 20 kHz, filter, and wash 3 times with pure water to obtain the metal extractant microcapsules.

[0070] The crosslinking agent used is obtained from Preparation Example 2; the emulsifier solution used is obtained from Preparation Example 5.

[0071] Example 3

[0072] A method for preparing metal extractant microcapsules, comprising the following preparation steps:

[0073] (1) Mix 0.1 mol of ethyl acrylate, 0.2 mol of methacrylamide, 0.175 mol of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 11.40 g of the crosslinking agent, and 3.04 g of the initiator uniformly. While stirring at 150 r / min, dropwise add 326 mL of the emulsifier solution, ultrasonically treat at 40 kHz for 15 min, under the stirring condition of 150 r / min, irradiate with a 2000 W ultraviolet lamp at a distance of 15 cm for 10 min, then wash 3 times with pure water, filter, and dry under vacuum to obtain the hollow microcapsules;

[0074] (2) Evacuate 39 g of the hollow microcapsules obtained in step (1), add 20 g of the metal chelating agent, ultrasonically treat for 8 h at 20 kHz, filter, and wash 3 times with pure water to obtain the metal extractant microcapsules.

[0075] The crosslinking agent used is obtained from Preparation Example 2; the emulsifier solution used is obtained from Preparation Example 5.

[0076] Example 4

[0077] A method for preparing metal extractant microcapsules, the specific implementation manner is the same as that of Example 3, the difference is that the crosslinking agent used is obtained from Preparation Example 3.

[0078] Example 5

[0079] A method for preparing metal extractant microcapsules, the specific implementation manner is the same as that of Example 3, the difference is that the crosslinking agent used is obtained from Preparation Example 4.

[0080] Example 6

[0081] A method for preparing metal extractant microcapsules, the specific implementation manner is the same as that of Example 3, the difference is that the emulsifier solution used is obtained from Preparation Example 6.

[0082] Example 7

[0083] A method for preparing metal extractant microcapsules, comprising the following preparation steps:

[0084] (1) Mix 0.1 mol of ethyl acrylate, 0.1 mol of methacrylamide, 0.175 mol of sodium 2-acrylamido-2-methylpropanesulfonate, 9.96 g of crosslinking agent, and 2.4 g of initiator evenly. While stirring at 150 r / min, add 326 mL of emulsifier solution dropwise. Sonicate for 15 min at 40 KHz. After irradiating with a 2000 W ultraviolet lamp at a distance of 15 cm for 10 min while stirring at 150 r / min, wash three times with pure water, filter, and dry in vacuum to obtain hollow microcapsules;

[0085] (2) Evacuate 39 g of the hollow microcapsules obtained in step (1), add 20 g of metal chelating agent, sonicate for 8 h at 20 KHz, filter, and wash three times with pure water to obtain metal extractant microcapsules.

[0086] The crosslinking agent used is obtained from Preparation Example 2; the emulsifier solution used is obtained from Preparation Example 5.

[0087] Example 8

[0088] A method for preparing metal extractant microcapsules, comprising the following preparation steps:

[0089] (1) Mix 0.1 mol of ethyl acrylate, 0.2 mol of methacrylamide, 0.1 mol of sodium 2-acrylamido-2-methylpropanesulfonate, 8.48 g of crosslinking agent, and 2.56 g of initiator evenly. While stirring at 150 r / min, add 326 mL of emulsifier solution dropwise. Sonicate for 15 min at 40 KHz. After irradiating with a 2000 W ultraviolet lamp at a distance of 15 cm for 10 min while stirring at 150 r / min, wash three times with pure water, filter, and dry in vacuum to obtain hollow microcapsules;

[0090] (2) Evacuate 39 g of the hollow microcapsules obtained in step (1), add 20 g of metal chelating agent, sonicate for 8 h at 20 KHz, filter, and wash three times with pure water to obtain metal extractant microcapsules.

[0091] The crosslinking agent used is obtained from Preparation Example 2; the emulsifier solution used is obtained from Preparation Example 5.

[0092] Example 9

[0093] A method for preparing metal extractant microcapsules, the specific implementation manner is the same as that of Example 3, except that the metal chelating agent used is 30 g.

[0094] Comparative Example 1

[0095] A method for preparing metal extractant microcapsules, the specific implementation is the same as that of Example 3, except that an equimolar amount of styrene is used instead of methacrylamide.

[0096] Performance testing of metal extractant microcapsules

[0097] The following performance tests were carried out on the examples and comparative examples:

[0098] 1. Encapsulation efficiency test of metal extractant microcapsules

[0099] Weigh 5 g of the metal extractant microcapsules obtained in the examples and comparative examples respectively, grind them in a mortar for 10 min, add 10 mL of dichloromethane to them, ultrasonicate for 15 min at 40 KHz and then centrifuge to obtain the supernatant and solid. Repeat this extraction process 5 times. Place the finally obtained solid in a vacuum oven and dry it to a constant weight, and record the weight as M. Calculate according to the following formula: Encapsulation efficiency (%) = 100% * (1 - M / 5); where 5 is the mass of the metal extractant microcapsules. The specific test results are shown in Table 1.

[0100] Table 1

[0101]

[0102] As can be seen from Table 1, the microcapsules in Examples 1 - 3 have a relatively high encapsulation efficiency for the metal chelating agent, which can reach more than 75%. Compared with Example 3, in Examples 4 and 5, the amounts of 1,4 - butanediol dimethacrylate and hexanediol dimethacrylate in the cross - linking agent used are changed, resulting in a weaker cross - linking effect of ethyl acrylate, methacrylamide and 2 - acrylamido - 2 - methylpropanesulfonic acid sodium salt, thus reducing the encapsulation efficiency of the wall material for the metal chelating agent; in Example 6, the emulsifier solution used is composed of sodium dodecylbenzenesulfonate dissolved in water, and the emulsifying effect of sodium dodecylbenzenesulfonate is worse than that of the emulsifier formed by the compounding of ethylenediaminoethanesulfonic acid sodium salt and sodium dodecyl diphenyl ether disulfonate, affecting the formation of the wall material, thus reducing the encapsulation efficiency; in Examples 7 and 8, the molar ratios of ethyl acrylate, methacrylamide and 2 - acrylamido - 2 - methylpropanesulfonic acid sodium salt are changed respectively, affecting the occurrence of the polymerization reaction and the performance of the wall material changes, thus reducing the encapsulation efficiency; in Example 9, the amount of the metal chelating agent used is large, and agglomeration is likely to occur, which also causes a decrease in the encapsulation efficiency; in Comparative Example 1, styrene is used instead of methacrylamide. On the one hand, it will affect the formation of the wall material. On the other hand, styrene lacks functional groups that are easy to generate intermolecular forces with the functional groups of the metal chelating agent, resulting in a certain degree of reduction in the encapsulation efficiency.

[0103] 2. Adsorption performance test of metal extractant microcapsules

[0104] Based on the data of Test 1, the metal extractant microcapsules obtained in Example 3 and Comparative Example 1 were selected for testing the metal ion adsorption performance:

[0105] Take 1 g of the metal extractant microcapsules of Example 3 and Comparative Example 1 and 1 g of the metal chelating agent of Preparation Example 1 respectively and place them in a 200 mL mixed solution with pH = 5 (the mixed solution includes 0.03 mol of copper sulfate pentahydrate, 0.001 mol of lead sulfate, 0.001 mol of nickel sulfate, 0.001 mol of zinc sulfate, 0.001 mol of iron sulfate, 0.001 mol of cobalt sulfate, 0.001 mol of magnesium sulfate, and 0.001 mol of chromium sulfate). Let it stand for 20 min, filter it with a 1-micron filter membrane filter, and then test the metal ion concentration in the solution. Calculate the removal rate according to the following formula: R = 100%*(C0 - C1) / C0, where C0 is the concentration of each metal ion in the solution before testing; C1 is the concentration of each metal ion in the solution after testing (unit: mol / L);

[0106] Among them, the copper ion concentration is determined according to the sodium diethyldithiocarbamate spectrophotometric method in the national standard GB / T 7474-87; the lead ion concentration is determined according to the dithizone spectrophotometric method in the national standard GB / T 7470-87; the nickel ion concentration is determined according to the dimethylglyoxime spectrophotometric method in the national standard GB 11910-89; the zinc ion concentration is determined according to the dithizone spectrophotometric method in the national standard GB 7472-87; the iron ion is determined according to the o-phenanthroline spectrophotometric method in the national standard HJ / T 345-2007; the cobalt ion is determined according to the flame atomic absorption spectrophotometric method in the national standard HJ 957-2018; the magnesium ion concentration is determined according to the ion chromatography method in the national standard HJ 812-2016; the chromium ion concentration is determined according to the flame atomic absorption spectrophotometric method in the national standard HJ 757-2015. The specific test results are shown in Table 2.

[0107] Table 2

[0108]

[0109] As can be seen from Table 2, when the usage amount is the same, the metal extractant microcapsules prepared in Example 3 have better adsorption performance for metal ions than the metal chelating agent obtained in Preparation Example 1, and have good removal effects on copper ions, lead ions, nickel ions, zinc ions, iron ions, cobalt ions, magnesium ions, and chromium ions, and can reduce the production cost to a certain extent. Compared with Example 3, in Comparative Example 1, styrene is used instead of methacrylamide, which on the one hand affects the formation of the microcapsule wall material and the encapsulation rate of the metal chelating agent, and on the other hand, the adsorption performance of the prepared metal extractant microcapsules for metals is also reduced.

[0110] As described above, it is only the preferred embodiment of the present invention and does not impose any form of limitation on this application. Although this application is disclosed as the preferred embodiment above, it is not intended to limit this application. Any person skilled in the art, without departing from the scope of the technical solution of this application, making some changes or modifications using the disclosed technical content above is equivalent to equivalent implementation cases. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution.

Claims

1. A method for preparing metal extractant microcapsules, characterized in that: The method comprises the following preparation steps: (1) Ethyl acrylate, methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid sodium salt, a crosslinking agent and an initiator are uniformly mixed, and an emulsifier solution is added dropwise under stirring conditions, ultrasonicated, and irradiated with ultraviolet light for 10-20 minutes under stirring conditions, and then washed with pure water, separated, and dried to obtain hollow microcapsules; (2) evacuating the hollow microcapsules obtained in step (1), adding a metal chelating agent, ultrasonically treating for 5-10 hours, filtering, and washing to obtain metal extractant microcapsules; The structural formula of the metal chelator is: ； The preparation method of the metal chelating agent comprises the following preparation steps: S1: dissolving dibutanolamine in anhydrous ethanol, adding carbon disulfide, reacting for 5-8 hours at 0-5°C in a nitrogen atmosphere, adjusting the pH to neutral with an aqueous sodium hydroxide solution, and rotary evaporating to obtain sodium di(4-hydroxybutyl)dithiocarbamate; S2: Add 4-[bis(β-chloroethyl)amino]benzaldehyde, sodium di(4-hydroxybutyl)dithiocarbamate obtained in step (1) and a catalyst to anhydrous ethanol, heat to reflux, remove the anhydrous ethanol under reduced pressure, add the obtained solid to pure water and stir, extract and combine the organic phases, dry the water in the organic phases, concentrate, let stand for 10-20 hours, separate, and obtain a metal chelating agent.

2. The method for preparing metal extractant microcapsules according to claim 1, characterized in that: The molar ratio of the ethyl acrylate, methacrylamide and 2-acrylamido-2-methylpropanesulfonic acid sodium salt is 1:(1.5-2.5):(1.5-2).

3. The method for preparing metal extractant microcapsules according to claim 1, characterized in that: The crosslinking agent includes 1,4-butanediol dimethacrylate and hexanediol dimethacrylate in a mass ratio of (25-30):

1.

4. The method for preparing metal extractant microcapsules according to claim 3, characterized in that: The usage amount of the cross-linking agent is 15-20% of the total mass of ethyl acrylate, methacrylamide and 2-acrylamido-2-methylpropanesulfonic acid sodium salt.

5. The method for preparing metal extractant microcapsules according to claim 1, characterized in that: The initiator is one or more of benzoin and its derivatives, acetophenones, aromatic ketones and acylphosphine oxides.

6. The method for preparing metal extractant microcapsules according to claim 1, characterized in that: The emulsifier in the emulsifier solution is one or more of sodium ethylenediamine ethanesulfonate, sodium dodecyl diphenyl ether disulfonate, and dodecylbenzene sulfonate; and the mass concentration of the emulsifier solution is 2-4.5wt%.

7. The method for preparing metal extractant microcapsules according to claim 6, characterized in that: The usage amount of the emulsifier is 16-18% of the total mass of ethyl acrylate, methacrylamide and 2-acrylamido-2-methylpropanesulfonic acid sodium salt.

8. The method for preparing metal extractant microcapsules according to claim 1, characterized in that: The mass ratio of the hollow microcapsules to the metal chelating agent in step (2) is (1.6-2.3):

1.

9. A metal extractant microcapsule prepared by the preparation method according to any one of claims 1 to 8.

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