Iminodiacetic acid type chelating resin and preparation method thereof

Abstract

The invention provides iminodiacetic acid type chelate resin and a preparation method thereof. The structural formula of the iminodiacetic acid type chelating resin is # imgabs 0 #, n ranges from 800 to 2000, the grafting rate of # imgabs 1 # ranges from 50% to 80%, each M is independently an alkali metal element, and R is selected from any one of a single bond, an alkylene group of C1 to C5 or an iminoalkylene group of C1 to C5. The n in the iminodiacetic acid type chelate resin is controlled to be within the range, so that the porosity, the specific surface area and the average pore size of the iminodiacetic acid type chelate resin are favorably optimized, and the adsorption efficiency of the iminodiacetic acid type chelate resin on divalent metal ions is favorably improved. The grafting rate is controlled within the range, so that the adsorption active sites in the iminodiacetic acid type chelating resin can be improved, and the adsorption capacity of the iminodiacetic acid type chelating resin on divalent metal ions can be further improved.

Description

Technical Field

[0001] This invention relates to the field of chelating resin technology, and more specifically, to an iminodiacetic acid type chelating resin and its preparation method. Background Technology

[0002] Iminodiacetic acid (IDAC) chelating resins primarily utilize IDAC chelating groups, exhibiting excellent adsorption selectivity for divalent metal ions. Chinese patent CN110003376B discloses a method for preparing nickel sulfate chelating resins from nickel-containing solutions. This method uses cross-linked polymeric spherical particles containing nitrile or ester groups as a base carrier, and the chelating resin is obtained through amination and carboxylation. However, existing IDAC-type resin preparation processes are complex, require large amounts of reagents, and are costly. Furthermore, the complex chemical structure of IDAC-type resins necessitates further improvement in their adsorption capacity for metal ions. Summary of the Invention

[0003] The main objective of this invention is to provide an iminodiacetic acid-type chelating resin and its preparation method, so as to solve the problems of low adsorption capacity for metal ions and complex preparation process of iminodiacetic acid-type chelating resin in the prior art.

[0004] To achieve the above objectives, according to one aspect of the present invention, an iminodiacetic acid-type chelating resin is provided, the general structural formula of which is: Where n is between 800 and 2000, The grafting rate is 50% to 80%, each M is an alkali metal element independently, and R is selected from any one of single bond, C1 to C5 alkylene or C1 to C5 iminoalkylene.

[0005] Furthermore, the porosity of the above-mentioned iminodiacetic acid type chelating resin is 0.20–0.30 cm³. 3 / g; and / or, the specific surface area of ​​the iminodiacetic acid type chelating resin is 20–55 m². 2 / g; and / or, the average pore size of the iminodiacetic acid chelating resin is 45–55 nm; and / or, the degree of crosslinking of the iminodiacetic acid chelating resin is 5–10%.

[0006] Furthermore, each M is independently Na or K; and / or, R is selected from single bonds, methylene, ethylene, or... Any one of them.

[0007] According to another aspect of the present invention, a method for preparing the aforementioned iminodiacetic acid-type chelating resin is provided, the method comprising: step S1, chloromethylating polystyrene resin In step S2, the swollen product is subjected to a swelling treatment in a first organic solvent to obtain a swollen product; in step S2, the swollen product, an amine solution, and a second organic solvent are subjected to an amination reaction to obtain an amination product. Step S3 involves a substitution reaction of the amination product, the acetic acidification reagent, an alkaline solution containing alkali metal ions, and water to obtain an iminodiacetic acid-type chelating resin; the acetic acidification reagent is a chloroacetic acid solution or a chloroacetic acid salt solution; wherein n, M, and R are the same as those mentioned above.

[0008] Further, the mass ratio of the acetic acid reagent to the chloromethylated polystyrene resin is 50–120:1–3; and / or, the mass ratio of the alkaline solution containing alkali metal ions to the chloromethylated polystyrene resin is 36–90:10–30; and / or, the temperature of the substitution reaction is 60–80°C; and / or, the time of the substitution reaction is 12–18 h; and / or, the mass concentration of the acetic acid reagent is 5–10%; and / or, the mass concentration of the alkali in the alkaline solution containing alkali metal ions is 5–20%; and / or, the mass ratio of water to the chloromethylated polystyrene resin is 5–10:1–3; and / or, the substitution reaction is carried out under stirring, and the stirring rate of the substitution reaction is 80–150 rpm; preferably, the alkaline solution containing alkali metal ions is an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide; and / or, the acetic acid reagent is selected from any one of an aqueous solution of chloroacetic acid, an aqueous solution of sodium chloroacetate, and an aqueous solution of potassium chloroacetate.

[0009] Further, step S3 includes: step S31, mixing the amination product and water to obtain a first mixed solution; step S32, adding the acetic acid reagent and an alkaline solution containing alkali metal ions dropwise to the first mixed solution, while the substitution reaction is carried out simultaneously with the dropwise addition; preferably, the dropwise addition rate of the acetic acid reagent is 1.4 to 2.8 g / min; and / or, the dropwise addition rate of the alkaline solution containing alkali metal ions is 1.0 to 2.5 g every 10 to 25 min.

[0010] Further, in step S2 above, the amination reaction temperature is 55–60°C; and / or, the amination reaction time is 12–24 h; and / or, the mass ratio of the second organic solvent to the chloromethylated polystyrene resin is 10–15:1–3; preferably, the amination reaction is carried out under stirring, and the stirring rate of the amination reaction is 100–250 rpm; and / or, the mass concentration of the amine in the amine solution is 25–50%; and / or, the mass ratio of the amine solution to the chloromethylated polystyrene resin is 8–20:1–3; preferably, the amine solution is selected from any one or more of aqueous methylamine, aqueous ethylamine, aqueous ethylenediamine, and aqueous propylamine; and / or, the second organic solvent is selected from any one or more of tetrahydrofuran, 1,2-dichloroethane, dichloromethane, and trichloromethane.

[0011] Further, step S2 includes: step S21, mixing the swollen product and the second organic solvent to obtain a second mixed solution; step S22, adding an amine solution dropwise to the second mixed solution, and performing an amination reaction after the addition is completed; preferably, the dropping rate of the amine solution is 2.7 to 6.7 g / min.

[0012] Further, in step S1 above, the mass ratio of the first organic solvent to the chloromethylated polystyrene resin is 10-15:1-3; and / or, the swelling treatment temperature is 20-30°C; and / or, the swelling treatment time is 2-6 hours; preferably, the first organic solvent is an alkane organic solvent; more preferably, the alkane organic solvent is selected from any one or more of 1,2-dichloroethane, dichloromethane, and trichloromethane.

[0013] Further, step S1 includes: removing impurities from the chloromethylated polystyrene resin and then swelling it with a first organic solvent; preferably, the removal treatment is carried out in a Soxhlet extractor; and / or, the removal agent in the removal treatment is anhydrous ethanol; and / or, the removal treatment time is 4 to 6 hours; and / or, the removal treatment temperature is 90 to 100°C.

[0014] By applying the technical solution of this application, controlling the 'n' in the iminodiacetic acid (IAA) chelating resin within the aforementioned range helps optimize the porosity, specific surface area, and average pore size of the IAA chelating resin, thereby improving its adsorption efficiency for divalent metal ions. Controlling the grafting rate within the aforementioned range helps increase the number of adsorption active sites in the IAA chelating resin, further enhancing its adsorption capacity for divalent metal ions. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0016] Figure 1 The infrared spectra of the chloromethylated polystyrene resin and the iminodiacetic acid-type chelating resin in Example 1 of this application are shown. Detailed Implementation

[0017] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] As analyzed in the background section of this application, existing iminodiacetic acid chelating resins have the problems of low adsorption capacity for metal ions and complex preparation processes. In order to solve this problem, this application provides an iminodiacetic acid chelating resin and its preparation method.

[0019] In a typical embodiment of this application, an iminodiacetic acid-type chelating resin is provided, the general structural formula of which is: Where n is between 800 and 2000, The grafting rate is 50% to 80%, each M is an alkali metal element independently, and R is selected from any one of single bond, C1 to C5 alkylene or C1 to C5 iminoalkylene.

[0020] This application, by controlling the concentration (n) in the iminodiacetic acid (MDA) chelating resin within the aforementioned range, helps optimize the porosity, specific surface area, and average pore size of the MAA chelating resin, thereby improving its adsorption efficiency for divalent metal ions. Controlling the grafting rate within the aforementioned range also helps increase the number of adsorption active sites in the MAA chelating resin, further enhancing its adsorption capacity for divalent metal ions.

[0021] In this application The grafting rate is related to the chloromethylated polystyrene resin, the temperature and time of the substitution reaction, the temperature and time of the amination reaction, the concentration and amount of amine solution added, the amount and dropping rate of the acetic acid reagent added, and the amount and dropping rate of the alkaline solution containing alkali metal ions added.

[0022] To further improve the adsorption capacity of the iminodiacetic acid-type chelating resin for divalent metal ions, in one embodiment of this application, the porosity of the iminodiacetic acid-type chelating resin is preferably 0.20–0.30 cm⁻¹. 3 / g; and / or, the specific surface area of ​​the iminodiacetic acid type chelating resin is 20–55 m². 2 / g; and / or, the average pore size of the iminodiacetic acid chelating resin is 45–55 nm; and / or, the degree of crosslinking of the iminodiacetic acid chelating resin is 5–10%.

[0023] Controlling the degree of crosslinking of iminodiacetic acid-type chelating resin within the above-mentioned range helps to improve the structural stability of iminodiacetic acid-type chelating resin.

[0024] In one embodiment of this application, each of the above M is independently Na or K; and / or, R is selected from single bonds, methylene, ethylene, or... Any one of them.

[0025] Controlling each M to be either Na or K independently helps to improve the selectivity of iminodiacetic acid chelating resins for divalent metal ions.

[0026] In another typical embodiment of this application, a method for preparing the aforementioned iminodiacetic acid-type chelating resin is provided, the method comprising: step S1, chloromethylating polystyrene resin In step S2, the swollen product is subjected to a swelling treatment in a first organic solvent to obtain a swollen product; in step S2, the swollen product, an amine solution, and a second organic solvent are subjected to an amination reaction to obtain an amination product. Step S3 involves a substitution reaction of the amination product, the acetic acidification reagent, an alkaline solution containing alkali metal ions, and water to obtain an iminodiacetic acid-type chelating resin; the acetic acidification reagent is a chloroacetic acid solution or a chloroacetic acid salt solution; wherein n, M, and R are the same as those mentioned above.

[0027] Swelling treatment of chloromethylated polystyrene resin with a first organic solvent can pre-adjust the pore structure of the chloromethylated polystyrene resin, making its pore size more uniform and providing more stable and open reaction sites for subsequent reactions. Amination reaction is then carried out in a second organic solvent to generate the amination product. The amination product, an alkaline solution containing alkali metal ions, and an acetic acidifying reagent undergo a substitution reaction. The alkali metal ions in the alkaline solution replace the hydrogen atom on the -CH₂COOH group in the acetic acidifying reagent, forming -CH₂COOM. The hydrogen atom on the -NH₂ group in the amination product is replaced by -CH₂COOM, resulting in an iminodiacetic acid-type chelating resin with highly selective adsorption capabilities. The iminodiacetic acid-type chelating resin of this application has a simple preparation process, high reagent utilization, and low cost.

[0028] In one embodiment of this application, the mass ratio of the acetic acid reagent to the chloromethylated polystyrene resin is 50–120:1–3; and / or, the mass ratio of the alkaline solution containing alkali metal ions to the chloromethylated polystyrene resin is 36–90:10–30; and / or, the temperature of the substitution reaction is 60–80°C; and / or, the time of the substitution reaction is 12–18 h; and / or, the mass concentration of the acetic acid reagent is 5–10%; and / or, the mass concentration of alkali in the alkaline solution containing alkali metal ions is 5–20%; and / or, the mass ratio of water to the chloromethylated polystyrene resin is 5–10:1–3; and / or, the substitution reaction is carried out under stirring, and the stirring rate of the substitution reaction is 80–150 rpm; preferably, the alkaline solution containing alkali metal ions is an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide; and / or, the acetic acid reagent is selected from any one of an aqueous solution of chloroacetic acid, an aqueous solution of sodium chloroacetate, and an aqueous solution of potassium chloroacetate.

[0029] Controlling the mass ratio of the acetic acid reagent to chloromethylated polystyrene resin, and the mass ratio of the alkaline solution containing alkali metal ions to chloromethylated polystyrene resin within the aforementioned ranges, helps ensure sufficient contact between reactants, improves reaction efficiency, and reduces the possibility of excess reactant residue, thereby contributing to improved purity and quality of the iminodiacetic acid-type chelating resin. Excessive temperature can easily damage the resin structure, and excessively long reaction times can easily cause side reactions. Controlling the temperature and time of the substitution reaction within the aforementioned ranges helps improve the metal adsorption capacity of the iminodiacetic acid-type chelating resin. Excessive concentration can easily lead to runaway reaction, while excessively low concentration is not conducive to complete reaction. Controlling the mass concentration of the acetic acid reagent and the mass concentration of alkali in the alkaline solution containing alkali metal ions within the aforementioned ranges helps improve the grafting rate of chelating groups, thereby improving the adsorption capacity of the iminodiacetic acid-type chelating resin for metal ions. The addition of water helps control the equilibrium of the reaction medium and the reaction rate. Controlling the mass ratio of water to chloromethylated polystyrene resin within the aforementioned ranges helps promote the uniform distribution of components in the solution, improving reaction efficiency. Controlling the stirring rate of the substitution reaction within the above-mentioned range helps to improve the uniformity of reactant distribution in solution and reduce the probability of local over- or under-reaction, thereby contributing to the improvement of the metal adsorption capacity of the iminodiacetic acid-type chelating resin. Controlling the types of alkaline solutions containing alkali metal ions and the aceticating reagents within the above-mentioned range helps to promote the formation of chelating groups.

[0030] In order to improve the purity of the iminodiacetic acid type chelating resin, in one embodiment of this application, the product of the above substitution reaction was washed with water until neutral and dried at 45-60°C for 8-16 hours to obtain the iminodiacetic acid type chelating resin.

[0031] In one embodiment of this application, step S3 includes: step S31, mixing the amination product and water to obtain a first mixed solution; step S32, adding the acetic acid reagent and an alkaline solution containing alkali metal ions dropwise to the first mixed solution, while the substitution reaction is carried out simultaneously with the dropwise addition; preferably, the dropwise addition rate of the acetic acid reagent is 1.4 to 2.8 g / min; and / or, the dropwise addition rate of the alkaline solution containing alkali metal ions is 1.0 to 2.5 g every 10 to 25 min.

[0032] This application employs a method of co-adding an acetic acid-based chelating resin with an acetic acid reagent and an alkaline solution containing alkali metal ions. This simplifies the preparation process and allows for better control of the reaction rate, thereby improving the synthesis efficiency of the iminodiacetic acid-based chelating resin. Controlling the dropping rates of the acetic acid reagent and the alkaline solution containing alkali metal ions within the aforementioned ranges helps to precisely control the rate of the substitution reaction, reducing the probability of excessively rapid reactions leading to byproduct formation or excessively slow reactions resulting in resource waste. Controlling the dropping rate also helps to regulate the pH value and reaction medium environment during the reaction process, thus improving the efficiency of iminodiacetic acid salt group formation.

[0033] In one embodiment of this application, in step S2 above, the temperature of the amination reaction is 55-60°C; and / or, the time of the amination reaction is 12-24 h; and / or, the mass ratio of the second organic solvent to the chloromethylated polystyrene resin is 10-15:1-3; preferably, the amination reaction is carried out under stirring, and the stirring rate of the amination reaction is 100-250 rpm; and / or, the mass concentration of the amine in the amine solution is 25-50%; and / or, the mass ratio of the amine solution to the chloromethylated polystyrene resin is 8-20:1-3; preferably, the amine solution is selected from any one or more of methylamine aqueous solution, ethylamine aqueous solution, ethylenediamine aqueous solution, and propylamine aqueous solution; and / or, the second organic solvent is selected from any one or more of tetrahydrofuran, 1,2-dichloroethane, dichloromethane, and trichloromethane.

[0034] Excessive temperature or prolonged reaction time can easily damage the resin structure or cause side reactions. Controlling the temperature and time of the amination reaction within the aforementioned range helps to increase the grafting rate of amine groups on the resin, thereby enhancing the subsequent binding ability of the chelating resin to metal ions. Controlling the mass ratio of the second organic solvent to chloromethylated polystyrene resin within the aforementioned range helps to provide a suitable medium environment for the amination reaction, thus helping to improve the efficiency of the amination reaction. Stirring helps to promote uniform mixing of reactants, reduce the occurrence of incomplete local reactions or overheating, and helps to improve the quality of iminodiacetic acid type chelating resins. Controlling the mass concentration of amine in the amine solution and the mass ratio of amine solution to chloromethylated polystyrene resin within the aforementioned range helps to improve the efficiency of the amination reaction and the purity of the product, while also helping to improve the uniformity of the distribution of amine groups on the resin surface. Controlling the types of amine solution and the second organic solvent within the aforementioned range helps to improve the stability of the resin during the amination reaction.

[0035] In one embodiment of this application, step S2 includes: step S21, mixing the swollen product and the second organic solvent to obtain a second mixed solution; step S22, adding an amine solution dropwise to the second mixed solution, and performing an amination reaction after the addition is completed; preferably, the dropping rate of the amine solution is 2.7 to 6.7 g / min.

[0036] Controlling the dropping rate of the amine solution within the above-mentioned range helps to improve the uniformity of the dispersion of the amine solution in the second mixed solution, thereby helping to improve the uniformity of the distribution of amine groups in the resin.

[0037] To further reduce the impurity content in the iminodiacetic acid-type chelating resin, in one embodiment of this application, the substances of the above-mentioned amination reaction were washed sequentially with tetrahydrofuran, dichloromethane, methanol, dimethylformamide, and methanol. The amount of each reagent was 100-150g, and the washing time for each reagent was 10min. After washing, the product was dried at 45-60℃ for 8-16h to obtain the amination product.

[0038] To further improve the swelling efficiency of chloromethylated polystyrene resin, in one embodiment of this application, in step S1 above, the mass ratio of the first organic solvent to the chloromethylated polystyrene resin is 10-15:1-3; and / or, the swelling treatment temperature is 20-30°C; and / or, the swelling treatment time is 2-6 hours; preferably, the first organic solvent is an alkane organic solvent; more preferably, the alkane organic solvent is selected from any one or more of 1,2-dichloroethane, dichloromethane, and trichloromethane.

[0039] To reduce the impact of impurities in chloromethylated polystyrene resin on the adsorption of metal ions by iminodiacetic acid-type chelating resin, in one embodiment of this application, step S1 preferably includes: removing impurities from the chloromethylated polystyrene resin and then subjecting it to swelling treatment with a first organic solvent; preferably, the removal treatment is performed in a Soxhlet extractor; and / or, the removal agent in the removal treatment is anhydrous ethanol; and / or, the removal treatment time is 4-6 hours; and / or, the removal treatment temperature is 90-100°C.

[0040] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0041] Example 1

[0042] (1) Add 10g of chloromethylated polystyrene resin particles (crosslinking degree 7%) to a Soxhlet extractor. The structural formula of the chloromethylated polystyrene resin is: When n is 1000, the chloromethylated polystyrene resin particles are treated with anhydrous ethanol at a temperature of 95°C for 4 hours to remove impurities, and the purified product is obtained.

[0043] (2) The above-mentioned purified product was placed in 100g of dichloromethane and swollen at 25°C for 4h to obtain the swollen product.

[0044] (3) Add 100g of tetrahydrofuran to the flask, add the swollen product from step (2) at 25°C, and slowly add 80g of 40% methylamine water at a rate of 2.7g / min under stirring at 100rpm. After adding the methylamine reagent, raise the temperature to 55°C to carry out the amination reaction, and reflux the amination reaction for 16h.

[0045] (4) Cool the above reaction product to room temperature, filter the resin, and wash the resin in sequence with tetrahydrofuran, dichloromethane, methanol, dimethylformamide and methanol. The amount of each reagent is 100g, and the washing time is 10min. After washing, dry at 45℃ for 8h to obtain the amination product.

[0046] (5) Add the amination product obtained in step (4) to 50g of pure water, stir at 100rpm until homogeneous, and heat to 60℃. Under stirring conditions, simultaneously add chloroacetic acid aqueous solution and sodium hydroxide aqueous solution. The amount of chloroacetic acid aqueous solution added is 500g, concentration is 5%, and the addition rate is 1.4g / min; the concentration of sodium hydroxide aqueous solution is 10%, and the amount of sodium hydroxide aqueous solution added is 36g, added intermittently, 1g every 10 minutes. During the reagent addition, maintain the substitution reaction temperature at 60℃, and the overall substitution reaction time is 16h.

[0047] (6) After the reaction in step (5) is completed, cool to room temperature, filter the resin, wash the resin with pure water until neutral, and dry at 50°C for 8 hours to finally obtain an iminodiacetic acid chelating resin. The structural formula of the iminodiacetic acid chelating resin is as follows: n is 1000, and the degree of crosslinking is 7%.

[0048] Example 2

[0049] The difference from Example 1 is that (1) 20g of chloromethylated polystyrene resin particles were added to a Soxhlet extractor, n was 800, and the chloromethylated polystyrene resin particles were treated with anhydrous ethanol to remove impurities. The temperature of the impurity removal treatment was 95°C and the time of the impurity removal treatment was 6h to obtain the impurity-removed product.

[0050] (2) The above-mentioned purified product was placed in 150g of dichloromethane and swollen at 25°C for 4h to obtain the swollen product.

[0051] (3) Add 150g of tetrahydrofuran to the flask, add the swollen product from step (2) at 25°C, and slowly add 150g of 40% methylamine water at a rate of 5.0g / min under stirring at 100rpm. After adding the methylamine reagent, raise the temperature to 60°C and reflux for 16h.

[0052] (4) Cool the above reaction product to room temperature, filter the resin, and wash the resin in sequence with tetrahydrofuran, dichloromethane, methanol, dimethylformamide and methanol. The amount of each reagent is 120g, and the washing time is 10min. After washing, dry at 45℃ for 8h to obtain the amination product.

[0053] (5) Add the amination product obtained in step (4) to 80g of pure water, stir at 100rpm until homogeneous, heat to 60℃, and simultaneously add chloroacetic acid aqueous solution and sodium hydroxide aqueous solution under stirring conditions. The amount of chloroacetic acid aqueous solution added is 1000g, the concentration is 5%, and the addition rate is 2.1g / min; the concentration of sodium hydroxide aqueous solution is 10%, and the amount of sodium hydroxide aqueous solution added is 54g, added intermittently, 1.5g every 10 minutes. During the reagent addition, the reaction temperature is maintained at 60℃, and the overall reaction time is 16h.

[0054] (6) After the reaction in step (5) is completed, cool to room temperature, filter the resin, wash the resin with pure water until neutral, dry at 50°C for 8 hours, and finally obtain iminodiacetic acid type chelating resin, in which n is 800.

[0055] Example 3

[0056] The difference from Example 1 is that (1) 30g of chloromethylated polystyrene resin particles were added to a Soxhlet extractor, n was 2000, and the chloromethylated polystyrene resin particles were treated with anhydrous ethanol to remove impurities. The temperature of the impurity removal treatment was 95°C and the time of the impurity removal treatment was 4h to obtain the impurity-removed product.

[0057] (2) The above-mentioned purified product was placed in 150g of dichloromethane and swollen at 25°C for 4h to obtain the swollen product.

[0058] (3) Add 150g of tetrahydrofuran to the flask, add the swollen product from step (2) at 25°C, and slowly add 180g of 40% methylamine water at a rate of 6.0g / min under stirring at 100rpm. After adding the methylamine reagent, raise the temperature to 55°C and reflux for 16h.

[0059] (4) Cool the above reaction product to room temperature, filter the resin, and wash the resin in sequence with tetrahydrofuran, dichloromethane, methanol, dimethylformamide and methanol. The amount of each reagent is 150g, and the washing time is 10min. After washing, dry at 45℃ for 8h to obtain the amination product.

[0060] (5) Add the amination product obtained in step (4) to 100g of pure water, stir at 100rpm until homogeneous, heat to 60℃, and simultaneously add chloroacetic acid aqueous solution and sodium hydroxide aqueous solution under stirring conditions. The amount of chloroacetic acid aqueous solution added is 1200g, the concentration is 5%, and the addition rate is 2.5g / min; the concentration of sodium hydroxide aqueous solution is 10%, and the amount of sodium hydroxide aqueous solution added is 72g, added intermittently, 2g every 10 minutes. During the reagent addition, the reaction temperature is maintained at 60℃, and the overall reaction time is 16h.

[0061] (6) After the reaction in step (5) is completed, cool to room temperature, filter the resin, wash the resin with pure water until neutral, and dry at 50°C for 8 hours to finally obtain iminodiacetic acid chelating resin. The n in the iminodiacetic acid chelating resin is 2000.

[0062] Example 4

[0063] The difference from Example 1 is that (1) 30g of chloromethylated polystyrene resin particles were added to a Soxhlet extractor and the chloromethylated polystyrene resin particles were treated with anhydrous ethanol to remove impurities. The temperature of the impurity removal treatment was 95°C and the time of the impurity removal treatment was 4h to obtain the impurity-removed product.

[0064] (2) The above-mentioned purified product was placed in 150g of dichloromethane and swollen at 25°C for 4h to obtain the swollen product.

[0065] (3) Add 150g of tetrahydrofuran to the flask, add the swollen product from step (2) at 25°C, and slowly add 200g of 40% methylamine water at a rate of 6.7g / min under stirring at 100rpm. After adding the methylamine reagent, raise the temperature to 55°C and reflux for 18h.

[0066] (4) Cool the above reaction product to room temperature, filter the resin, and wash the resin in sequence with tetrahydrofuran, dichloromethane, methanol, dimethylformamide and methanol. The amount of each reagent is 150g, and the washing time is 10min. After washing, dry at 45℃ for 8h to obtain the amination product.

[0067] (5) Add the amination product obtained in step (4) to 100g of pure water, stir at 100rpm until homogeneous, heat to 60℃, and simultaneously add chloroacetic acid aqueous solution and sodium hydroxide aqueous solution under stirring conditions. The amount of chloroacetic acid aqueous solution added is 1000g, the concentration is 8%, and the addition rate is 2.8g / min; the concentration of sodium hydroxide aqueous solution is 10%, and the amount of sodium hydroxide aqueous solution added is 90g, added intermittently, 2.5g every 10 minutes. During the reagent addition, the reaction temperature is maintained at 80℃, and the overall reaction time is 16h.

[0068] (6) After the reaction in step (5) is completed, cool to room temperature, filter the resin, wash the resin with pure water until neutral, and dry at 50°C for 8 hours to finally obtain iminodiacetic acid type chelating resin.

[0069] Example 5

[0070] The difference from Example 1 is that the degree of crosslinking of the chloromethylated polystyrene resin is 5%, and the final product is an iminodiacetic acid chelating resin with a degree of crosslinking of 5%.

[0071] Example 6

[0072] The difference from Example 1 is that the degree of crosslinking of the chloromethylated polystyrene resin is 10%, and the final product is an iminodiacetic acid chelating resin with a degree of crosslinking of 10%.

[0073] Example 7

[0074] The difference from Example 1 is that the degree of crosslinking of the chloromethylated polystyrene resin is 15%, and the final product is an iminodiacetic acid chelating resin with a degree of crosslinking of 15%.

[0075] Example 8

[0076] The difference from Example 1 is that the temperature of the substitution reaction is 80°C and the time of the substitution reaction is 12 hours, finally obtaining an iminodiacetic acid type chelating resin.

[0077] Example 9

[0078] The difference from Example 1 is that the substitution reaction temperature is 90°C and the substitution reaction time is 10 hours, ultimately yielding an iminodiacetic acid-type chelating resin.

[0079] Example 10

[0080] The difference from Example 1 is that the amount of chloroacetic acid aqueous solution added is 1200g, the mass concentration of chloroacetic acid in the chloroacetic acid aqueous solution is 10%, the mass concentration of sodium hydroxide in the sodium hydroxide aqueous solution is 20%, and the amount of sodium hydroxide aqueous solution added is 90g, finally obtaining an iminodiacetic acid type chelating resin.

[0081] Example 11

[0082] The difference from Example 1 is that the amount of chloroacetic acid aqueous solution added is 1300g, the mass concentration of chloroacetic acid in the chloroacetic acid aqueous solution is 15%, the mass concentration of sodium hydroxide in the sodium hydroxide aqueous solution is 25%, and the amount of sodium hydroxide aqueous solution added is 100g, finally obtaining an iminodiacetic acid type chelating resin.

[0083] Example 12

[0084] The difference from Example 1 is that the addition rate of chloroacetic acid aqueous solution is 2.8 g / min, and 1 g of sodium hydroxide aqueous solution is added every 25 min to finally obtain iminodiacetic acid type chelating resin.

[0085] Example 13

[0086] The difference from Example 1 is that the addition rate of chloroacetic acid aqueous solution is 3.5 g / min, and 1 g of sodium hydroxide aqueous solution is added every 30 min to finally obtain iminodiacetic acid type chelating resin.

[0087] Example 14

[0088] The difference from Example 1 is that the amination reaction temperature is 60°C and the amination reaction time is 12 hours, ultimately yielding an iminodiacetic acid-type chelating resin.

[0089] Example 15

[0090] The difference from Example 1 is that the amination reaction temperature is 70°C and the amination reaction time is 10 hours, finally obtaining an iminodiacetic acid type chelating resin.

[0091] Example 16

[0092] The difference from Example 1 is that 200g of 25% methylamine water was slowly added at a rate of 6.7g / min to finally obtain an iminodiacetic acid type chelating resin.

[0093] Example 17

[0094] The difference from Example 1 is that 250g of 10% methylamine water was slowly added at a rate of 10g / min to finally obtain an iminodiacetic acid type chelating resin.

[0095] Example 18

[0096] The difference from Example 1 is that an aqueous solution of ethylenediamine was used instead of an aqueous solution of methylamine. The mass concentration of the aqueous solution of ethylenediamine was 40%, ultimately yielding an iminodiacetic acid-type chelating resin. The structural formula of the iminodiacetic acid-type chelating resin is as follows: n is 1000, and the degree of crosslinking is 7%.

[0097] Comparative Example 1

[0098] The difference from Example 1 is that the chloromethylated polystyrene resin has the following structural formula: When n is 10000, an iminodiacetic acid chelating resin is finally obtained, where n is 10000.

[0099] Performance testing

[0100] Grafting rate: In the formula, GP represents the functional group grafting rate, and m1 and m2 represent the mass of the resin before and after the reaction, respectively.

[0101] Cu adsorption capacity: The saturated adsorption capacity of the resin is obtained by stirring the resin with a metal ion solution and testing the change in the metal ion content in the solution before and after adsorption.

[0102] Accurately weigh 1g of the prepared iminodiacetic acid-type chelating resin into a 250mL Erlenmeyer flask. Use a pipette to add 100mL of a prepared Cu metal ion solution of a specific concentration to the Erlenmeyer flask. Place the Erlenmeyer flask containing the resin and metal solution in a constant-temperature shaker at 30℃ and 120 rpm for 24 hours. After shaking, collect 30mL of the adsorbed solution for elemental concentration determination.

[0103] The formula for calculating the saturated adsorption capacity of resin is as follows: In the formula, Q e C represents the saturated adsorption capacity of the resin. o C represents the initial concentration of the metal ion solution. e The concentration of the metal ion solution when adsorption is complete; V is the volume of the metal ion solution; m is the mass of the dry resin.

[0104] The iminodiacetic acid-type chelating resins prepared in the examples and comparative examples were subjected to... The grafting rate, porosity, specific surface area, average pore size and Cu adsorption amount were tested, and the test results are shown in Table 1.

[0105] Table 1

[0106]

[0107]

[0108] Figure 1 The infrared spectra of the chloromethylated polystyrene resin and the iminodiacetic acid-type chelating resin in Example 1 of this application are shown below. Figure 1It can be seen that the chloromethylated polystyrene resin mainly contains C-Cl bonds (674.59 cm⁻¹). -1 ) and saturated CH bonds (2921.93cm) -1 The -CO- bond in the carboxylic acid group was detected in the prepared iminodiacetic acid chelating resin (1396.71 cm⁻¹). -1 ) and hydroxyl group (-OH, 3401.63cm -1 ) and CN bond (1633.26cm) -1 This indicates that grafting has been successfully performed on iminodiacetic acid-type chelating resins.

[0109] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0110] This application, by controlling the concentration (n) in the iminodiacetic acid (MDA) chelating resin within the aforementioned range, helps optimize the porosity, specific surface area, and average pore size of the MAA chelating resin, thereby improving its adsorption efficiency for divalent metal ions. Controlling the grafting rate within the aforementioned range also helps increase the number of adsorption active sites in the MAA chelating resin, further enhancing its adsorption capacity for divalent metal ions.

[0111] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An iminodiacetic acid type chelating resin, characterized in that, The general structural formula of the iminodiacetic acid type chelating resin is: Among them, n is 800~2000, The grafting rate is 50% to 80%, each M is independently an alkali metal element, and R is selected from any one of a single bond, a C1 to C5 alkylene group, or a C1 to C5 iminoalkylene group.

2. iminodiacetic acid type chelating resin according to claim 1, is characterized in that, The porosity of the iminodiacetic acid chelating resin is 0.20 to 0.30 cm 3 / g; and / or, the specific surface area of ​​the iminodiacetic acid type chelating resin is 20 to 55 m 2 / g; and / or, the average pore size of the iminodiacetic acid chelating resin is 45 to 55 nm; and / or, the cross-linking degree of the iminodiacetic acid chelating resin is 5 to 10%.

3. according to claim 1 or 2 described iminodiacetic acid type chelating resin, it is characterized in that, Each of the M is independently Na or K; and / or, the R is selected from a single bond, a methylene group, an ethylene group or Any one of .

4. A method for preparing the iminodiacetic acid type chelating resin according to any one of claims 1 to 3, characterized in that: The preparation method comprises: Step S1, chloromethylating polystyrene resin Performing a swelling treatment in a first organic solvent to obtain a swollen product; Step S2, subjecting the swelling product, the amine solution and the second organic solvent to an amination reaction to obtain an amination product Step S3, subjecting the amination product, an acetating agent, an alkaline solution containing alkali metal ions and water to a substitution reaction to obtain the iminodiacetic acid type chelating resin; the acetating agent is a chloroacetic acid solution or a chloroacetate solution; wherein n, M and R are the same as n, M and R described in claim 1.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the acetic acidizing agent to the chloromethylated polystyrene resin is 50-120:1-3; and / or the mass ratio of the alkaline solution containing alkali metal ions to the chloromethylated polystyrene resin is 36-90:10-30; and / or, the temperature of the substitution reaction is 60 to 80° C.; and / or, the time of the substitution reaction is 12 to 18 hours; And / or, the mass concentration of the acetic acid reagent is 5-10%; And / or, the mass concentration of alkali in the alkaline solution containing alkali metal ions is 5 to 20%; And / or, the mass ratio of the water to the chloromethylated polystyrene resin is 5-10:1-3; And / or, the substitution reaction is carried out under stirring, and the stirring rate of the substitution reaction is 80 to 150 rpm; Preferably, the alkaline solution containing alkali metal ions is an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution; And / or, the acetylating agent is selected from any one of a chloroacetic acid aqueous solution, a sodium chloroacetate aqueous solution and a potassium chloroacetate aqueous solution.

6. The preparation method according to claim 4 or 5, characterized in that: The step S3 comprises: Step S31, mixing the amination product and the water to obtain a first mixed solution; Step S32, dropping the acetylating agent and the alkaline solution containing alkali metal ions into the first mixed solution, and performing the substitution reaction while dropping; Preferably, the dripping speed of the acetylating agent is 1.4 to 2.8 g / min; and / or the dripping speed of the alkaline solution containing alkali metal ions is 1.0 to 2.5 g per 10 to 25 min interval.

7. The preparation method according to any one of claims 4 to 6, characterized in that: In step S2, the temperature of the amination reaction is 55 to 60° C.; and / or the time of the amination reaction is 12 to 24 hours; and / or, the mass ratio of the second organic solvent to the chloromethylated polystyrene resin is 10-15:1-3; Preferably, the amination reaction is carried out under stirring, and the stirring rate of the amination reaction is 100 to 250 rpm; And / or, the mass concentration of amine in the amine solution is 25-50%; and / or, the mass ratio of the amine solution to the chloromethylated polystyrene resin is 8-20:1-3; Preferably, the amine solution is selected from any one or more of a methylamine aqueous solution, an ethylamine aqueous solution, an ethylenediamine aqueous solution and a propylamine aqueous solution; And / or, the second organic solvent is selected from any one or more of tetrahydrofuran, 1,2-dichloroethane, dichloromethane, and chloroform.

8. The preparation method according to any one of claims 4 to 7, characterized in that The step S2 comprises: Step S21, mixing the swelling product and the second organic solvent to obtain a second mixed solution; Step S22, adding the amine solution dropwise to the second mixed solution, and performing the amination reaction after the addition is completed; Preferably, the dropping speed of the amine solution is 2.7 to 6.7 g / min.

9. The preparation method according to any one of claims 4 to 8, characterized in that: In the step S1, the mass ratio of the first organic solvent to the chloromethylated polystyrene resin is 10-15:1-3; and / or, the temperature of the swelling treatment is 20 to 30° C.; and / or, the time of the swelling treatment is 2 to 6 hours; Preferably, the first organic solvent is an alkane organic solvent; further preferably, the alkane organic solvent is selected from any one or more of 1,2-dichloroethane, dichloromethane and chloroform.

10. The preparation method according to any one of claims 4 to 9, characterized in that: The step S1 comprises: performing a de-impurity treatment on the chloromethylated polystyrene resin, and then performing a swelling treatment with the first organic solvent; Preferably, the impurity removal treatment is carried out in a Soxhlet extractor; And / or, the impurity removal agent in the impurity removal treatment is anhydrous ethanol; and / or, the time of the impurity removal treatment is 4 to 6 hours; and / or, the temperature of the impurity removal treatment is 90 to 100°C.

Images