An adsorption material, preparation method and application of ternary deep eutectic solvent synergistic DTPA-functionalized Fe3O4 magnetic microspheres for rapid and efficient removal of high concentrations of Cr(VI) from wastewater.

Abstract

This invention belongs to the field of synthesis technology and application of macromolecular polymer materials, and discloses a ternary deep eutectic solvent synergistic DTPA functionalized Fe3O4 magnetic microsphere adsorption material, its preparation method and application. The preparation method mainly includes the following steps: (1) preparing the ternary deep eutectic solvent DETA-Im-Eg; (2) heating anhydrous sodium acetate, ferric chloride hexahydrate and 1,6-hexanediamine at high temperature to form aminated Fe3O4 (Fe3O4-NH2); (3) dissolving diethyltriaminepentaacetic acid in ammonia solution, adding 1-ethyl(3-dimethylaminopropyl)-3-carbodiimide and N-hydroxysuccinimide after the pH is acidic, and reacting fully, then adding Fe3O4-NH2 and DETA-Im-Eg, and reacting in nitrogen to obtain DTPA / DETA-Im-Eg@Fe3O4. (4) Post-processing: The precipitate was obtained by filtration with anhydrous ethanol and dried to obtain a black powder, which is the ternary deep eutectic solvent-synthesized DTPA-functionalized Fe3O4 magnetic microsphere adsorption material. The synthesis of this invention is simple and environmentally friendly; the prepared magnetic microspheres can rapidly and efficiently process high-concentration Cr(VI) solutions and have excellent recycling capacity.

Description

Technical Field

[0001] This invention belongs to the field of synthesis technology and application of macromolecular polymer materials, specifically relating to an adsorption material, preparation method and application of ternary deep eutectic solvent synergistic DTPA functionalized Fe3O4 magnetic microspheres for rapid and efficient removal of high concentrations of Cr(VI) from wastewater. Background Technology

[0002] In recent years, the uncontrolled discharge of toxic heavy metals into water bodies has seriously harmed the ecological environment and human health, drawing widespread attention. Cr(VI) is a highly toxic heavy metal ion found in oilfield wastewater and industrial wastewater. It is mainly produced by oilfield development, electroplating, leather tanning, and other industrial processes, and inadequate regulatory systems have led to the accumulation of Cr(VI) in water bodies.

[0003] Currently, methods for remediating Cr(VI) pollution in aquatic environments mainly include ion exchange, chemical precipitation, membrane separation, photocatalytic reduction, and adsorption. Adsorption and reduction methods are widely used due to their cost-effectiveness, efficiency, simplicity, and excellent results. However, traditional adsorbents (such as molecular sieves, activated carbon, and natural clay) suffer significant loss during use, are difficult to recycle, and can easily cause re-pollution. Therefore, using magnetic nanoparticles as the core-shell structure of the adsorbent facilitates the recovery of the adsorbent from the mobile phase, reducing environmental risks. Iron oxide is the most widely used magnetic nanoparticle, primarily due to its ease of synthesis, low toxicity, low cost, and convenient recovery.

[0004] Macromolecular polymers exhibit thermodynamic stability and strong cycling ability. Nanopolymer microspheres possess diverse pore structures, large specific surface areas, and abundant micropores and mesopores. Furthermore, the surface of nanopolymer microspheres contains adsorption sites such as primary amines and hydroxyl groups, demonstrating excellent adsorption effects for heavy metals. Studies have shown that ternary deep eutectic solvent synergistic DTPA-functionalized Fe3O4 magnetic microspheres enhance the adsorption performance for Cr(VI), achieving efficient and rapid adsorption of Cr(VI). Based on this, this invention proposes a preparation method to obtain ternary deep eutectic solvent synergistic DTPA-functionalized Fe3O4 magnetic microspheres and apply them to the adsorption of Cr(VI). Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a method for synthesizing ternary deep eutectic solvent-synthesized DTPA-functionalized Fe3O4 magnetic microspheres and their application in the field of adsorption. The most common amidation reaction preparation method is used to prepare micro-nano macromolecular polymer microspheres with abundant pore structure, adsorption sites such as primary amines and hydroxyl groups, and high removal rate. When applied to the adsorption of heavy metals, it has an excellent adsorption effect on Cr(VI) generated in industrial wastewater.

[0006] To achieve the objectives of this invention, the method for synthesizing ternary deep eutectic solvent-assisted DTPA-functionalized Fe3O4 magnetic microspheres includes the following steps:

[0007] (1) Preparation of ternary deep eutectic solvent: Diethylenetriamine, imidazole and ethylene glycol were heated to react, a pale yellow liquid was collected, and vacuum dried to finally obtain a pale yellow transparent liquid. The ternary deep eutectic solvent was labeled as DETA-Im-Eg.

[0008] (2) Anhydrous sodium acetate, ferric chloride hexahydrate, and 1,6-hexanediamine are stirred thoroughly and heated at high temperature to form aminated Fe3O4 (Fe3O4-NH2);

[0009] (3) Dissolve diethyltriaminepentaacetic acid (DTPA) in ammonia solution, adjust the pH, and then add 1-ethyl(3-dimethylaminopropyl)-3-carbodiimide (EDAC) and N-hydroxysuccinimide (NHS) to react fully;

[0010] (4) Add the Fe3O4-NH2 obtained in step (2) to the solution in step (3), and then add the product (DETA-Im-Eg) obtained in step (1). After the reaction is complete under nitrogen atmosphere, DTPA / DETA-Im-Eg@Fe3O4 is obtained.

[0011] Furthermore, in some embodiments of the present invention, the molar ratio of diethylenetriamine to imidazole in step (1) is 0.015-0.025:0.02-0.035; and the molar ratio of diethylenetriamine to ethylene glycol is 0.025-0.03:0.02-0.025.

[0012] Preferably, in some embodiments of the present invention, the molar ratio of anhydrous sodium acetate, ferric chloride hexahydrate, and 1,6-hexanediamine is 0.01-0.035 mol: 0.0095-0.0105 mol: 0.115-0.125 mol.

[0013] Furthermore, in some embodiments of the present invention, the heating reaction in step (1) is carried out at 60-90°C for 3-5 hours.

[0014] Furthermore, in some embodiments of the present invention, the ratio of anhydrous sodium acetate to ferric chloride hexahydrate in step (2) is 0.85-2.50g:2-3.2g.

[0015] Furthermore, in some embodiments of the present invention, the molar ratio of ferric chloride hexahydrate to aniline in step (2) is 0.0025-0.0055:0.0005-0.001.

[0016] Furthermore, in some embodiments of the present invention, the molar ratio of ferric chloride hexahydrate and 1,6-hexanediamine in step (2) is 0.01-0.025:0.1-0.13.

[0017] Furthermore, in some embodiments of the present invention, the high-temperature heating reaction in step (2) is carried out at 200-230°C for 4-8 hours.

[0018] Furthermore, in some embodiments of the present invention, the volume molar ratio of diethyltriaminepentaacetic acid, 1-ethyl(3-dimethylaminopropyl)-3-carbodiimide, N-hydroxysuccinimide and ammonia solution in step (3) is: 0.025-0.03mol: 0.0015-0.0025: 0.0022-0.003: 50-80ml.

[0019] Furthermore, in some embodiments of the present invention, the pH adjustment to acidity in step (3) is adjusted to the range of 4-6.5.

[0020] Furthermore, in some embodiments of the present invention, the full reaction in step (3) is carried out at 60-80°C for 2-4 hours.

[0021] Furthermore, in some embodiments of the present invention, the ratio of Fe3O4-NH2, DETA-Im-Eg and the solution in step (3) is 0.3-0.5g:1.5-2.5g:50-80ml.

[0022] Furthermore, in some embodiments of the present invention, in step (4), the reaction in a nitrogen atmosphere is first carried out at 50-60°C for 1-2 hours, and then the temperature is raised to 50-90°C for 18-26 hours.

[0023] Furthermore, in some embodiments of the present invention, the drying in steps (1) and (5) is performed at 60-90°C for 12-16 hours.

[0024] This invention protects a ternary deep eutectic solvent-assisted DTPA-functionalized Fe3O4 magnetic microsphere, which is prepared by the above-described preparation method.

[0025] This invention also protects the application of ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres prepared by the above preparation method in heavy metal adsorption, wherein the application is for adsorbing Cr(VI) in wastewater.

[0026] The preparation method provided by this invention utilizes the principles of oxidation and amidation reactions. The resulting ternary deep eutectic solvent-assisted DTPA-functionalized Fe3O4 magnetic microspheres possess abundant micro-mesoporous structures and are rich in primary amines, hydroxyl groups, and other functional groups. The adsorbed Cr(VI) exhibits high electronegativity at a certain pH and is not easily degraded. Therefore, the ternary deep eutectic solvent-assisted DTPA-functionalized Fe3O4 magnetic microspheres demonstrate extremely strong adsorption performance for Cr(VI), capable of rapidly and efficiently adsorbing 125 mg / L Cr(VI) solutions. Furthermore, the ternary deep eutectic solvent-assisted DTPA-functionalized Fe3O4 magnetic microspheres are inexpensive and highly reusable (the adsorption efficiency remains above 90% after six adsorption-desorption cycles).

[0027] The advantages of this invention are as follows:

[0028] (1) The process of this invention is simple and inexpensive. The ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres are rich in primary amines, hydroxyl groups and other functional groups. This material can play a good adsorption role for high concentrations of heavy metal pollutants that cannot be degraded, and still has excellent removal effect after being recycled six times.

[0029] (2) This invention uses Fe3O4-NH2 as the core-shell structure, which not only facilitates recovery but also provides sites for subsequent amidation reactions, enabling DTPA and DETA-Im-Eg to undergo amidation reactions, increasing the number of primary amines, hydroxyl groups, and other functional groups. This greatly improves the adsorption capacity for Cr(VI), resulting in high removal efficiency and significant separation. Attached Figure Description

[0030] Figure 1 The image shows the FTIR spectrum of the ternary deep eutectic solvent obtained in the embodiments of the present invention.

[0031] Figure 2 The image shows the FTIR spectrum of ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres obtained in the embodiments of the present invention.

[0032] Figure 3 XRD pattern of ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres prepared in this embodiment of the invention;

[0033] Figure 4 (A) is a graph showing the adsorption effect of ternary deep eutectic solvent synergistic with DTPA-functionalized Fe3O4 magnetic microspheres on Cr(VI) solutions of different concentrations prepared in the embodiments of the present invention.

[0034] Figure 4(B) is a graph showing the adsorption effect of ternary deep eutectic solvent synergistic with DTPA-functionalized Fe3O4 magnetic microspheres on Cr(VI) solution at different temperatures prepared in the embodiments of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. It should be understood that the following description is merely illustrative and not intended to limit the invention.

[0036] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0037] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all the scope formed by any pairing of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0038] The indefinite article "a" preceding an element or component of this invention does not impose a limit on the quantity requirement (i.e., the number of times) of the element or component. Therefore, "a" or "an" should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0039] Furthermore, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., described below refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example. Moreover, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0040] Example 1

[0041] The synthesis of Fe3O4 magnetic microspheres by DTPA-functionalized with a ternary deep eutectic solvent formed by diethylenetriamine, imidazole and ethylene glycol (i.e., DETA-Im-Eg is added in step (4)).

[0042] (1) Preparation of deep eutectic solvent: 2.58g diethylenetriamine, 1.36g imidazole and 1.24g ethylene glycol were thoroughly mixed and heated at 70℃. The pale yellow liquid was collected and dried under vacuum at 60℃ for 12h. Finally, a pale yellow transparent liquid was obtained, which was denoted as DETA-Im-Eg.

[0043] (2) 0.95g of anhydrous sodium acetate, 2.54g of ferric chloride hexahydrate and 11.62g of 1,6-hexanediamine were stirred thoroughly and heated at 205℃ for 5h to form aminated Fe3O4 (Fe3O4-NH2).

[0044] (3) Dissolve 9.83g of diethyltriaminepentaacetic acid (DTPA) in an ammonia solution, adjust the pH to 5.5, and then add 0.29g of 1-ethyl(3-dimethylaminopropyl)-3-carbodiimide (EDAC) and 0.25g of N-hydroxysuccinimide (NHS) and react for 2 hours.

[0045] (4) Add 0.35g Fe3O4-NH2 obtained in step (1) to the solution in step (3), and then add the product (2.0g DETA-Im-Eg) in step (2). After the reaction is complete under nitrogen atmosphere, DTPA / DETA-Im-Eg@Fe3O4 is obtained.

[0046] (5) The DTPA / DETA-Im-Eg@Fe3O4 obtained in step (4) is post-processed. First, it is washed several times with anhydrous ethanol, filtered, and the black solid is collected. The black magnetic solid is vacuum dried at 70°C for 14 hours. Finally, the black solid powder is the ternary deep eutectic solvent-synergistic DTPA functionalized Fe3O4 magnetic microspheres prepared in this invention.

[0047] Experimental Example 1

[0048] The successful preparation of the ternary deep eutectic solvent was demonstrated by characterizing it using FTIR. The FTIR of DETA-Im-Eg was as follows: Figure 1 As shown.

[0049] Experimental Example 2

[0050] The successful preparation of the ternary deep eutectic solvent-synthetic DTPA-functionalized Fe3O4 magnetic microspheres prepared in Example 1 was demonstrated by FTIR characterization. The FTIR of DTPA / DETA-Im-Eg@Fe3O4 was as follows: Figure 2 As shown.

[0051] The adsorption experiment was conducted to verify the adsorption effect of the adsorbent prepared in Example 1 of this invention. A high-concentration Cr(VI) solution of 125 mg / L was used as the adsorbate. 50 ml of the solution was taken, and the amount of adsorbent was 0.02 g. Adsorption was carried out at 25 °C. The adsorption data of the ternary deep eutectic solvent synergistic with DTPA functionalized Fe3O4 magnetic microspheres are shown in Table 1.

[0052] Table 1 shows the adsorption data of high-concentration Cr(VI) solution by ternary deep eutectic solvent synergistic with DTPA-functionalized Fe3O4 magnetic microspheres in Example 1.

[0053]

[0054] The data in the table show that DTPA / DETA-Im-Eg@Fe3O4 exhibits excellent adsorption performance for high concentrations of Cr(VI), reaching equilibrium in approximately 30 minutes with a removal efficiency of 99.7%, fully meeting water quality discharge standards. Furthermore, the table also demonstrates the crucial role of the amidation reaction of the ternary deep eutectic solvent in the adsorption process. The removal efficiency improved from not meeting water quality requirements (43.06%) to meeting discharge standards (99.7%).

[0055] Experimental Example 3

[0056] Adsorption experiments were conducted on the nanospheres prepared in Example 1 at different concentrations, such as... Figure 4 As shown in (A), the adsorption effect of DTPA-functionalized Fe3O4 magnetic microspheres prepared in the embodiment of the present invention on Cr(VI) solutions of different concentrations is as follows: it can be found that DTPA / DETA-Im-Eg@Fe3O4 has an excellent adsorption effect on Cr(VI), with the highest adsorption capacity reaching 312.45 mg / g.

[0057] Test Example 4

[0058] Adsorption experiments were conducted on the nanospheres prepared in Example 1 at different temperatures, such as... Figure 4As shown in (B), the adsorption effect of DTPA-functionalized Fe3O4 magnetic microspheres prepared in the embodiment of the present invention on Cr(VI) solution at different temperatures is shown. It can be found that the adsorption effect of DTPA / DETA-Im-Eg@Fe3O4 on Cr(VI) solution increases with increasing temperature, indicating that the adsorption effect of DTPA / DETA-Im-Eg@Fe3O4 on Cr(VI) solution is a spontaneous endothermic reaction.

[0059] The above experiments demonstrate that the ternary deep eutectic solvent synergistic DTPA-functionalized Fe3O4 magnetic microspheres obtained in this invention possess a rapid and efficient adsorption capacity for high concentrations of Cr(VI). Even after six cycles of adsorbing a 125 mg / L Cr(VI) solution, the residual liquid still meets water quality discharge standards, greatly enriching the options for heavy metal treatment in water. Furthermore, the adsorption behavior of the ternary deep eutectic solvent synergistic DTPA-functionalized Fe3O4 magnetic microspheres is an endothermic reaction; higher temperatures are more conducive to adsorption.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, alterations, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres, characterized in that, Includes the following steps: (1) Preparation of ternary deep eutectic solvent: Diethylenetriamine, imidazole and ethylene glycol were heated to react, a pale yellow liquid was collected, and vacuum dried to obtain a pale yellow transparent liquid. The ternary deep eutectic solvent was labeled as DETA-Im-EG. (2) Anhydrous sodium acetate, ferric chloride hexahydrate and 1,6-hexanediamine are stirred thoroughly and heated at high temperature to form aminated Fe3O4, namely Fe3O4-NH2; (3) Dissolve diethyltriaminepentaacetic acid (DTPA) in an ammonia solution, adjust the pH to acidic, and then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDAC) and N-hydroxysuccinimide (NHS) to react fully. (4) Add the Fe3O4-NH2 obtained in step (2) to the solution in step (3), and then add the DETA-Im-EG obtained in step (1). After the reaction is complete under a nitrogen atmosphere, DTPA / DETA-Im-EG@Fe3O4 is obtained. (5) The magnetic microspheres obtained in step (4) are post-processed. First, they are washed several times with anhydrous ethanol, filtered, and the precipitate is collected. The precipitate is dried thoroughly, and finally a black solid powder is obtained, which is the ternary deep eutectic solvent-synergistic DTPA functionalized Fe3O4 magnetic microspheres.

2. The preparation method of ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, In step (1), the molar ratio of diethylenetriamine to imidazole is 0.015-0.025:0.02-0.035; the molar ratio of diethylenetriamine to ethylene glycol is 0.025-0.03:0.02-0.

025.

3. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, The heating reaction in step (1) is carried out at 60-90℃ for 3-5 hours.

4. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, The molar ratio of anhydrous sodium acetate, ferric chloride hexahydrate, and 1,6-hexanediamine is 0.01-0.035 mol: 0.0095-0.0105 mol: 0.115-0.125 mol.

5. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, In step (2), the high-temperature heating reaction is carried out at 200-230℃ for 4-8 hours.

6. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, In step (2), the ratio of anhydrous sodium acetate to ferric chloride hexahydrate is 0.85-2.50g:2-3.2g.

7. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, In step (2), the molar ratio of ferric chloride hexahydrate to 1,6-hexanediamine is 0.01-0.025:0.1-0.

13.

8. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, The pH adjustment in step (3) is to adjust it to 4-6.

5.

9. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, The full reaction in step (3) is carried out at 60-80℃ for 2-4 hours.

10. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, In step (4), the ratio of Fe3O4-NH2, DETA-Im-EG and the solution in step (3) is 0.3-0.5g:1.5-2.5g:50-80ml.

11. The method for preparing ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 1, characterized in that, In steps (1) and (5), the drying process is carried out at 60-90℃ for 12-16 hours.

12. A ternary deep eutectic solvent-synergistic DTPA-functionalized Fe3O4 magnetic microsphere, characterized in that, The ternary deep eutectic solvent-assisted DTPA functionalized Fe3O4 magnetic microspheres were prepared according to any one of claims 1-11.

13. The application of the ternary deep eutectic solvent synergistic DTPA-functionalized Fe3O4 magnetic microspheres according to claim 12 in heavy metal adsorption, characterized in that, The application is for adsorbing Cr(VI) from water.

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