Metal chelator and preparation method and application thereof

Abstract

The application relates to the field of chelator preparation, in particular to a high-efficiency metal chelator and a preparation method and application thereof. The preparation method comprises the following preparation steps: (1) dissolving dibutanolamine in anhydrous ethanol, adding carbon disulfide, reacting under a nitrogen atmosphere at 0-5 DEG C for 5-8 h, adjusting the pH to neutral by using a sodium hydroxide aqueous solution, rotary evaporating, and obtaining sodium bis(4-hydroxybutyl) dithiocarbamate; (2) adding 4-[bis(beta-chloroethyl) amino] benzaldehyde, the sodium bis(4-hydroxybutyl) dithiocarbamate in step (1) and a catalyst in anhydrous ethanol, heating and refluxing, removing the anhydrous ethanol under reduced pressure, stirring the obtained solid in pure water, extracting and combining the organic phases, drying the moisture in the organic phases, concentrating, standing for 10-20 h, separating, and obtaining the metal chelator. The metal chelator prepared by the application has good dispersibility and solubility in various solvents, can be coordinated and chelated with heavy metal ions through active functional groups, and forms stable metal chelates.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chelating agent preparation, and particularly relates to a high-efficiency metal chelating agent and a preparation method and application thereof. BACKGROUND

[0002] High-purity metal salt solution has a wide range of applications in functional thin films, integrated circuit wires, magnetic sensing, magnetic recording sputtering targets, high-purity reagents and standard sample preparation, etc. due to its special structure and performance, especially in the production process of sputtering targets, the purity of the metal salt solution is extremely high. For example, in the production process of traditional nickel chloride solution, the copper is generally removed by extraction and sodium sulfide precipitation. Although the copper removal effect is obvious, the compound formed by the extractant and copper is unstable, which increases the extraction stages and cannot guarantee the stability of the extraction system.

[0003] Metal chelating agents can bind metal ions inside the chelating agent by strong combination of chelating agent molecules and metal ions, becoming stable and larger molecular weight compounds, thereby preventing metal ions from acting. Metal chelating agents can be used in detoxification, printing and dyeing, scale inhibition, extraction, etc. The commonly used metal extractants in the preparation of high-purity metal salt solution include P2O4, amine extractant, Lix984, etc. Patent CN 113981219 A discloses a method for separating nickel and cobalt in a nickel chloride solution by using an amine extractant, which includes the following steps: an acidification step, in which an organic phase composed of an amine extractant, isooctanol and sulfonated kerosene is added to an acidification section; an extraction step, in which a nickel chloride solution is added to an extraction section; a nickel washing step, in which a nickel washing acid is added to a nickel washing section to wash nickel; and a cobalt washing step, in which a cobalt washing acid is added to a cobalt washing section to wash cobalt. Patent CN 114085993 A discloses a method for separating calcium, magnesium and manganese in a nickel chloride solution by using an extraction method, which includes a saponification step of continuously countercurrently extracting an organic phase composed of P2O4 extractant and sulfonated kerosene and a sodium hydroxide solution into a saponification section, and then transporting the organic phase after saponification into an extraction section for extraction, nickel and cobalt washing, and miscellaneous washing to obtain a nickel chloride solution. However, the extraction sections in the above two patents are 8 stages and 10 stages, respectively, and the extraction stages are relatively high. In addition, different types of metal chelating agents on the market have different selectivity and the chelates formed with different metal ions are not stable, which also increases the extraction stages.

[0004] Based on the problems in the prior art, a high-performance metal chelating agent is developed, which has high selectivity for target metals and forms stable chelates to reduce the extraction stages, save manpower and cost, and is of great significance to industrial production. SUMMARY

[0005] To solve the above technical problems, the application provides a high-efficiency metal chelating agent, a preparation method and application thereof. The prepared metal chelating agent has good dispersibility and solubility in various solvents, can be quickly reacted with heavy metal ions to generate insoluble and stable coordination chelates through coordination chelation of nitrogen atoms, oxygen atoms and sulfur atoms, and has good application prospects in the fields of adsorption such as sewage treatment, water quality detection and solution purification.

[0006] To achieve the above object, the application adopts the technical scheme as follows.

[0007] The application provides a preparation method of a high-efficiency metal chelating agent, which comprises the following preparation steps.

[0008] (1) Dissolve dibutanolamine in anhydrous ethanol, add carbon disulfide, react for 5-8 h under a nitrogen atmosphere at 0-5 ℃, adjust the pH to neutral with a sodium hydroxide aqueous solution, and perform rotary evaporation to obtain sodium bis(4-hydroxybutyl)dithiocarbamate;

[0009] (2) Add 4-[bis(β-chloroethyl)amino]benzaldehyde, the sodium bis(4-hydroxybutyl)dithiocarbamate obtained in step (1) and a catalyst in 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 phase, concentrate, stand for 10-20 h, and separate to obtain the metal chelating agent.

[0010] In some embodiments, the molar ratio of the dibutanolamine to the carbon disulfide is 1:(1-1.2).

[0011] Preferably, the molar ratio of the dibutanolamine to the carbon disulfide is 1:1.1.

[0012] In some embodiments, the molar ratio of the 4-[bis(β-chloroethyl)amino]benzaldehyde to the sodium bis(4-hydroxybutyl)dithiocarbamate in step (2) is 1:(2-2.5).

[0013] Preferably, the molar ratio of the 4-[bis(β-chloroethyl)amino]benzaldehyde to the sodium bis(4-hydroxybutyl)dithiocarbamate in step (2) is 1:2.35.

[0014] In some embodiments, the catalyst is one or more of potassium iodide, potassium bromide and potassium chloride.

[0015] In some embodiments, the amount of the catalyst is 1-1.5% of the total molar amount of the 4-[bis(β-chloroethyl)amino]benzaldehyde and the sodium bis(4-hydroxybutyl)dithiocarbamate.

[0016] Preferably, the catalyst is potassium iodide, and the amount of the catalyst is 1.25% of the total moles of 4-[bis(beta-chloroethyl)amino]benzaldehyde and sodium bis(4-hydroxybutyl)dithiocarbamate.

[0017] In some embodiments, the heating reflux temperature is 85-95℃, and the time is 20-30h.

[0018] Preferably, the heating reflux temperature is 90℃, and the time is 25h.

[0019] In some embodiments, the extractant used in the extraction is dichloromethane and / or chloroform.

[0020] The second aspect of the present application provides a metal chelator prepared by the preparation method described above, and the structural formula of the metal chelator is as follows:

[0021]

[0022] In some embodiments, the yield of the metal chelator is greater than or equal to 70.8%.

[0023] The third aspect of the present application provides an application of the metal chelator described above in the adsorption field.

[0024] The metal chelator in the present application has good chelating ability and can be used alone or in combination with other substances, and has good application prospects in the adsorption field such as sewage treatment, water quality detection, and solution purification.

[0025] In the present application, dibutanolamine and carbon disulfide are chemically reacted under condition control, sodium hydroxide is used to adjust pH, sodium bis(4-hydroxybutyl)dithiocarbamate is generated, and then sodium bis(4-hydroxybutyl)dithiocarbamate and generated 4-[bis(beta-chloroethyl)amino]benzaldehyde are chemically reacted to generate a new type of metal chelator. The metal chelator has good dispersibility and solubility in various solvents, coordinates and chelates with heavy metal ions through nitrogen atoms, oxygen atoms, and sulfur atoms, and forms stable metal chelates.

[0026] The hydroxybutyl in the sodium bis(4-hydroxybutyl) dithiocarbamate is introduced to the 4-[bis(beta-chloroethyl)amino] benzaldehyde, on one hand, the hydroxyl itself has a certain chelating ability, which can improve the performance of the metal chelating agent to a certain extent; on the other hand, the hydroxybutyl can also improve the stability of the chelating agent and the metal complex. This may be due to the introduction of the hydroxybutyl, which can improve the electron density on the surface of the chelating agent molecule and enhance the bond strength between the atoms in the chelating agent molecule, and the hydroxybutyl in the chelating agent is symmetrically distributed, the symmetry of the chelating agent molecule is higher, and it is easier to combine with metal ions to form a symmetric chelate ring, thereby improving the stability of the chelate. In addition, the -N(C6H4)CHO in the structure can also provide electronic force for the C-S bond, thereby improving the coordination ability with metal ions. The symmetrically distributed hydroxybutyl structure in the chelating agent molecule will not be limited by the position of the electron, and the electron cloud density of the dithiocarbamate active functional group will be increased, so that the electron-donating ability of the sulfur atom is improved, the lone pair of electrons on the sulfur atom forms a coordination bond with the metal ion, and a high-stability metal chelate is formed.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The present application controls the conditions to make the sodium bis(4-hydroxybutyl) dithiocarbamate and the 4-[bis(beta-chloroethyl)amino] benzaldehyde react chemically to generate a new type of metal chelating agent. The metal chelating agent has good dispersibility and solubility in various solvents, and can coordinate and chelate with heavy metal ions through active atoms such as nitrogen atoms, oxygen atoms and sulfur atoms to form stable metal chelates. The operation steps of the present application are simple, and the metal chelating agent prepared has good application prospect in the adsorption field. DETAILED DESCRIPTION

[0029] The various illustrative embodiments of the present application will now be described in detail in connection with the following figures. This description is not to be considered limiting in scope, but rather as being illustrative of the various aspects, configurations and embodiments of the present application. It is understood that the use of specific terms to describe particular embodiments is solely for the purpose of providing a clear and thorough understanding of the present application. Furthermore, any specific units and ranges, unless otherwise specified, are intended to be variable with the understanding that the application is applicable to any and all suitable ranges and units. Moreover, it is to be understood that where the application, or any features thereof, is / are described herein with the aid of one or more particular embodiments, it is the application itself, and not only the specific embodiments, that is / are provided.

[0030] Unless otherwise indicated, all technical and scientific terms have the same meaning as those one of ordinary skill in the art of the present application would understand. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. Numerous modifications and adaptations thereof will be apparent to those skilled in the art without departing from the scope or spirit of the present application. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only.

[0031] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having" or "contains", "containing", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, includes, has, contains a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0032] The catalyst used in the present application is potassium iodide; the extractant used in Examples 1-9 and Comparative Example 1 is dichloromethane, and the extractant used in Example 10 is ethyl acetate.

[0033] Example 1

[0034] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0035] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1 mol of carbon disulfide, and react at 0°C under a nitrogen atmosphere for 5 h. Then, adjust the pH to neutral with a 2 mol / L sodium hydroxide aqueous solution, and perform rotary evaporation to obtain sodium bis(4-hydroxybutyl) dithiocarbamate;

[0036] (2) Add 0.1 mol of 4-[bis(β-chloroethyl)amino]benzaldehyde, 0.2 mol of the sodium bis(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 3 mmol of a catalyst to 500 mL of anhydrous ethanol, and heat to reflux at 85°C for 30 h. Then, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract the organic phase with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase by adding 15 g of sodium sulfate, concentrate to 50 mL, stand for 10 h, and filter to obtain the metal chelator.

[0037] Example 2

[0038] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0039] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.1 mol of carbon disulfide, react for 6 h at 0°C under a nitrogen atmosphere, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and spin to obtain sodium bis(4-hydroxybutyl) dithiocarbamate;

[0040] (2) Add 0.1 mol of 4-[bis(β-chloroethyl)amino]benzaldehyde, 0.235 mol of the sodium bis(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 4.19 mmol of a catalyst to 500 mL of anhydrous ethanol, heat to reflux at 90°C for 25 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract the organic phase with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase by adding 15 g of sodium sulfate, concentrate to 50 mL, stand for 20 h, and filter to obtain the metal chelator.

[0041] Example 3

[0042] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0043] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.2 mol of carbon disulfide, react for 5 h at 0°C under a nitrogen atmosphere, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and spin to obtain sodium bis(4-hydroxybutyl) dithiocarbamate;

[0044] (2) Add 0.1 mol of 4-[bis(β-chloroethyl)amino]benzaldehyde, 0.25 mol of the sodium bis(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 5.25 mmol of a catalyst to 500 mL of anhydrous ethanol, heat to reflux at 95°C for 20 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract the organic phase with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase by adding 15 g of sodium sulfate, concentrate to 50 mL, stand for 15 h, and filter to obtain the metal chelator.

[0045] Example 4

[0046] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0047] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 0.9 mol of carbon disulfide, react for 6 h at 0°C under a nitrogen atmosphere, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and spin to obtain sodium bis(4-hydroxybutyl) dithiocarbamate;

[0048] (2) In 500 mL of anhydrous ethanol, add 0.1 mol of 4-[bis(β-chloroethyl)amino] benzaldehyde, 0.235 mol of the sodium di(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 4.19 mmol of a catalyst, heat to reflux at 90°C for 25 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract the organic phase with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase with 15 g of sodium sulfate, concentrate to 50 mL, stand for 20 h, and filter to obtain the metal chelator.

[0049] Example 5

[0050] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0051] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.3 mol of carbon disulfide, react at 0°C under a nitrogen atmosphere for 6 h, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and rotary evaporate to obtain sodium di(4-hydroxybutyl) dithiocarbamate;

[0052] (2) In 500 mL of anhydrous ethanol, add 0.1 mol of 4-[bis(β-chloroethyl)amino] benzaldehyde, 0.235 mol of the sodium di(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 4.19 mmol of a catalyst, heat to reflux at 90°C for 25 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract the organic phase with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase with 15 g of sodium sulfate, concentrate to 50 mL, stand for 20 h, and filter to obtain the metal chelator.

[0053] Example 6

[0054] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0055] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.3 mol of carbon disulfide, react at 0°C under a nitrogen atmosphere for 6 h, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and rotary evaporate to obtain sodium di(4-hydroxybutyl) dithiocarbamate;

[0056] (2) In 500 mL of anhydrous ethanol, add 0.1 mol of 4-[bis(β-chloroethyl)amino] benzaldehyde, 0.19 mol of sodium di(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 3.625 mmol of a catalyst, heat to reflux at 90°C for 25 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase by adding 15 g of sodium sulfate, concentrate to 50 mL, stand for 20 h, and filter to obtain the metal chelator.

[0057] Example 7

[0058] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0059] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.1 mol of carbon disulfide, react at 0°C under a nitrogen atmosphere for 6 h, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and rotary evaporate to obtain sodium di(4-hydroxybutyl) dithiocarbamate;

[0060] (2) In 500 mL of anhydrous ethanol, add 0.1 mol of 4-[bis(β-chloroethyl)amino] benzaldehyde, 0.26 mol of sodium di(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 4.5 mmol of a catalyst, heat to reflux at 90°C for 25 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase by adding 15 g of sodium sulfate, concentrate to 50 mL, stand for 20 h, and filter to obtain the metal chelator.

[0061] Example 8

[0062] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0063] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.1 mol of carbon disulfide, react at 0°C under a nitrogen atmosphere for 6 h, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and rotary evaporate to obtain sodium di(4-hydroxybutyl) dithiocarbamate;

[0064] (2) In 500 mL of anhydrous ethanol, add 0.1 mol of 4-[bis(β-chloroethyl)amino] benzaldehyde, 0.235 mol of the sodium di(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 4.19 mmol of a catalyst, heat to reflux at 85°C for 25 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract the organic phase with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase with 15 g of sodium sulfate, concentrate to 50 mL, stand for 20 h, and filter to obtain the metal chelator.

[0065] Example 9

[0066] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0067] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.1 mol of carbon disulfide, react at 0°C under a nitrogen atmosphere for 6 h, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and rotary evaporate to obtain sodium di(4-hydroxybutyl) dithiocarbamate;

[0068] (2) In 500 mL of anhydrous ethanol, add 0.1 mol of 4-[bis(β-chloroethyl)amino] benzaldehyde, 0.235 mol of the sodium di(4-hydroxybutyl) dithiocarbamate obtained in step (1), and 3.02 mmol of a catalyst, heat to reflux at 90°C for 25 h, remove the anhydrous ethanol under reduced pressure, add the obtained solid to 500 mL of pure water, stir, extract the organic phase with 250 mL of dichloromethane three times, combine the organic phases, dry the organic phase with 15 g of sodium sulfate, concentrate to 50 mL, stand for 20 h, and filter to obtain the metal chelator.

[0069] Example 10

[0070] A method for preparing a high-efficiency metal chelator, comprising the following preparation steps:

[0071] (1) Dissolve 1 mol of dibutanolamine in 500 mL of anhydrous ethanol, add 1.1 mol of carbon disulfide, react at 0°C under a nitrogen atmosphere for 6 h, adjust the pH to neutral with a 2 mol / L aqueous sodium hydroxide solution, and rotary evaporate to obtain sodium di(4-hydroxybutyl) dithiocarbamate;

[0072] (2) In 500 mL of anhydrous ethanol, 0.1 mol of 4-[bis(β-chloroethyl)amino]benzaldehyde, 0.235 mol of the sodium salt of bis(4-hydroxybutyl) dithiocarbamic acid obtained in step (1), and 4.19 mmol of a catalyst were added, and after heating under reflux at 90°C for 25 h, the anhydrous ethanol was removed under reduced pressure, the obtained solid was added to 500 mL of pure water and stirred, and the organic phase was extracted with 250 mL of ethyl acetate three times, and the organic phase was combined. After drying the organic phase by adding 15 g of sodium sulfate, the water content was concentrated to 50 mL, and after standing for 20 h, the metal chelate was obtained by filtration.

[0073] Comparative Example 1

[0074] A method for preparing a metal chelate, comprising the following preparation steps:

[0075] In 500 mL of anhydrous ethanol, 0.1 mol of 4-[bis(β-chloroethyl)amino]benzaldehyde, 0.235 mol of the sodium salt of bis(4-hydroxybutyl) dithiocarbamic acid obtained in step (1), and 4.19 mmol of a catalyst were added, and after heating under reflux at 90°C for 25 h, the anhydrous ethanol was removed under reduced pressure, the obtained solid was added to 500 mL of pure water and stirred, and the organic phase was extracted with 250 mL of dichloromethane three times, and the organic phase was combined. After drying the organic phase by adding 15 g of sodium sulfate, the water content was concentrated to 50 mL, and after standing for 20 h, the metal chelate was obtained by filtration.

[0076] Performance test of metal chelate

[0077] 1. Determination of yield of metal chelate

[0078] The yield of the metal chelate obtained in each of the examples and comparative examples was calculated according to the following formula: Y = m2 / m1 x 100%, wherein m1 represents the theoretical yield of the metal chelate (unit: g); and m2 represents the actual yield of the metal chelate (unit: g).

[0079] The specific test results are shown in Table 1.

[0080] Table 1

[0081]

[0082] From Table 1, it can be seen that the metal chelating agents prepared in Examples 1-3 have a high yield, which can reach more than 70.8%, and the yield of the metal chelating agent in Example 2 is the highest, reaching 72.9%. Compared with Example 2, the use amount of carbon disulfide is changed in Examples 4 and 5, which affects the generation and properties of sodium bis(4-hydroxybutyl) dithiocarbamate, so that the yield of the metal chelating agent is reduced. In Examples 6 and 7, the use amount of sodium bis(4-hydroxybutyl) dithiocarbamate is changed, which is not conducive to the reaction, so that the yield of the metal chelating agent is reduced. In Example 8, the reflux temperature is reduced, the reaction rate is reduced, and the yield of the metal chelating agent is also affected to some extent. In Example 9, the amount of catalyst is changed, the catalytic performance and the reaction rate are reduced, and the yield of the metal chelating agent is also affected. In Example 10, the extractant used is ethyl acetate, and the solubility of the generated metal chelating agent in ethyl acetate is significantly reduced compared with dichloroethane, which causes a higher loss, so that the yield of the metal chelating agent is significantly reduced.

[0083] Based on the test results of the yield, the metal chelating agents obtained in Example 2 and Comparative Example 1 are selected for testing of the chelating performance.

[0084] 2. Test of chelating performance of metal chelating agent

[0085] 1g of the metal chelating agent in Example 2 or Comparative Example 1 is respectively dissolved in 100mL of a mixed metal ion solution with pH=5 (including 0.01mol of copper sulfate pentahydrate, 0.01mol of lead sulfate and 0.01mol of nickel sulfate), and after standing for 20min, the solution is filtered, and the concentration of metal ions in the solution is tested, and the removal rate is calculated according to the following formula: R=100%*(C0-C1) / C0, wherein C0 is the concentration of each metal ion in the solution before testing (0.1mol / L); C1 is the concentration of each metal ion in the solution after testing (unit: mol / L).

[0086] Among them, the concentration of copper ions is determined by the diethyl dithiocarbamate spectrophotometric method in the national standard GB / T 7474-87; the concentration of lead ions is determined by the dithizone spectrophotometric method in the national standard GB / T 7470-87; and the concentration of nickel ions is determined by the dimethylglyoxime spectrophotometric method in the national standard GB 11910-89.

[0087] The specific test results are shown in Table 2.

[0088] Table 2

[0089]

[0090] As shown in Table 2, the metal chelator prepared in Example 2 can chelate metal ions well, and has good removal effect on copper ions, lead ions and nickel ions, but the removal rate of nickel ions is smaller than that of copper ions and lead ions, which may be due to that the chelation of the metal chelator to nickel is weaker than that to copper ions and lead ions when the pH of the solution is 5; the removal effect of the metal chelator prepared in Comparative Example 1 on copper ions, lead ions and nickel ions is obviously reduced, which may be due to that the chelator in Example 2 has more hydroxyl functional groups and nitrogen and sulfur adsorption active sites, which can chelate a large amount of metal ions and improve the removal rate.

[0091] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application is disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and the equivalent embodiments are equivalent. Any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present application are still within the scope of the technical solution.

Claims

1. A process for the preparation of a metal chelator, characterized by, The preparation method comprises the following steps: (1) dissolving dibutylamine in anhydrous ethanol, adding carbon disulfide, reacting for 5-8 hours under nitrogen atmosphere at 0-5℃, adjusting pH to neutral with sodium hydroxide aqueous solution, and rotary evaporation to obtain sodium bis(4-hydroxybutyl) dithiocarbamate; (2) adding 4-[bis(β-chloroethyl)amino] benzaldehyde, sodium bis(4-hydroxybutyl) dithiocarbamate obtained in step (1) and a catalyst in anhydrous ethanol, heating to reflux, removing anhydrous ethanol under reduced pressure, stirring the obtained solid in pure water, extracting, combining organic phases, drying the moisture in the organic phase, concentrating, standing for 10-20 hours, separating, and obtaining a metal chelating agent; the molar ratio of dibutylamine to carbon disulfide is 1:(1-1.2); the molar ratio of 4-[bis(β-chloroethyl)amino] benzaldehyde to sodium bis(4-hydroxybutyl) dithiocarbamate in step (2) is 1:(2-2.5); the catalyst is potassium iodide; the amount of the catalyst is 1-1.5% of the total moles of 4-[bis(β-chloroethyl)amino] benzaldehyde and sodium bis(4-hydroxybutyl) dithiocarbamate; the heating temperature is 85-95℃, and the heating time is 20-30 hours; the extractant used in the extraction is dichloromethane and / or trichloromethane; the structural formula of the metal chelating agent is: 。 2. A metal chelating agent prepared by the preparation method of claim 1.

3. Application of the metal chelating agent prepared by the preparation method of claim 1 or the metal chelating agent of claim 2 in the field of adsorption.

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