Preparation method of amidoxime functionalized metal organic framework as well as product and application of amidoxime functionalized metal organic framework

Abstract

The invention provides a preparation method of an amidoxime functionalized metal organic framework as well as a product and application of the amidoxime functionalized metal organic framework, the method comprises the following steps: (1) mixing 2, 5-dibromoterephthalic acid, a zirconium source and a coordination regulator in a solvent, and reacting to obtain a metal organic framework UiO-66-2Br; (2) mixing the UiO-66-2Br and a cyanation reagent in a solvent, and reacting to obtain a metal organic framework UiO-66-2CN; (3) mixing the hydroxylamine salt, an alkaline reagent and UiO-66-2CN in a solvent, and reacting to obtain an amidoxime functionalized metal organic framework UiO-66-2AO; the hydroxylamine salt comprises any one or a combination of at least two of hydroxylamine nitrate, hydroxylamine sulfate or hydroxylamine oxalate. The UiO-66-2AO has high adsorption capacity for uranyl ions in a wide pH range, and efficient separation of rare earth ions and uranyl ions is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of material preparation, and particularly relates to a preparation method of an amidoamine functionalized metal organic framework, a product thereof and application thereof. BACKGROUND

[0002] Rare earth elements are important industrial raw materials, and have wide application prospects in the fields of magnetic materials, catalytic materials, luminescent materials and electronic devices due to their unique magnetic, catalytic and luminescent properties. The rare earth resources in China often coexist with natural radioactive elements in minerals, and the produced rare earth materials contain trace but non-negligible radioactive components. High-precision separation of rare earth elements and radioactive elements has become a major technical obstacle to the high-quality development of the downstream industry of rare earth.

[0003] For the separation of radioactive elements in rare earth, the current industrial technologies include chemical precipitation method, solvent extraction method, ion exchange method, biological method, adsorption method and membrane separation technology. Compared with other existing separation methods, the adsorption method has the characteristics of simple operation, high efficiency, wide application range, no emulsification phenomenon and high enrichment multiple, and is one of the widely studied methods for separation of uranyl. Among the existing adsorption materials, metal organic framework materials have significant advantages due to their highly designable crystal structure. The pore size and surface chemical properties can be accurately controlled by selecting organic ligands and metal nodes, so as to realize high-selectivity recognition and capture of uranyl ions. In addition, functional groups (such as amidoamine and phosphoric acid groups) can be precisely introduced into the inner wall of the pore, and form strong coordination with uranyl ions, thereby enhancing the binding force and improving the anti-interference ability of the material in complex solution system, providing an ideal platform for efficient and selective enrichment and separation of uranyl.

[0004] Although certain progress has been made in the synthesis of metal organic frameworks in existing research, there are still many challenges in practical application, such as the generally insufficient hydrothermal stability, especially the easy structural collapse or degradation in acidic or salt-containing uranium adsorption environment, which limits the service life and reusability; the high synthesis cost (including organic ligands and metal salt precursors) and complex and time-consuming preparation process also hinder the large-scale promotion of such materials in the field of rare earth purification. Therefore, it is still a key problem to be solved in the technical field to develop a functionalized metal organic framework material with stable structure, excellent adsorption performance and easy large-scale preparation, so as to realize efficient and high-selectivity separation of radioactive elements in rare earth. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a preparation method of an amidoamine functionalized metal organic framework, its product and application, wherein the amidoamine functionalized metal organic framework UiO-66-2AO has a high adsorption capacity for uranyl ions in a wide pH range, and realizes efficient separation of rare earth ions and uranyl ions.

[0006] To achieve the purpose of the present application, the following technical solutions are adopted in the present application:

[0007] In the first aspect, the present application provides a preparation method of an amidoamine functionalized metal organic framework, which comprises:

[0008] (1) mixing 2,5-dibromoterephthalic acid, a zirconium source and a coordination regulator in a solvent, and reacting to obtain a metal organic framework UiO-66-2Br;

[0009] (2) mixing the UiO-66-2Br and a cyanylating agent in a solvent, and reacting to obtain a metal organic framework UiO-66-2CN;

[0010] (3) mixing a hydroxylamine salt, an alkaline agent and the UiO-66-2CN in a solvent, and reacting to obtain an amidoamine functionalized metal organic framework UiO-66-2AO;

[0011] The hydroxylamine salt includes any one or a combination of at least two of hydroxylamine nitrate, hydroxylamine sulfate or hydroxylamine oxalate.

[0012] The present application breaks through the limitation of the existing single functional group adsorption, and constructs a unique synergistic adsorption mechanism by introducing a double amidoamine group. In the mechanism, a double amidoamine unit can act as a special "chelating pocket" for a uranyl ion. Two adjacent amidoamine groups coordinate with a uranyl ion through the nitrogen and oxygen atoms thereon, forming an integrated structure with a highly stable structure and containing two five-membered chelating rings. The binding affinity for the uranyl ion is significantly improved, and excellent structural stability and ion selectivity are maintained in a wide pH range and a complex ion environment, realizing efficient separation of rare earth ions and uranyl ions.

[0013] Preferably, in step (1), the zirconium source includes any one or a combination of at least two of zirconium chloride, zirconium oxychloride, zirconyl nitrate or zirconium acetate.

[0014] Preferably, the coordination regulator includes any one or a combination of at least two of benzoic acid, acetic acid or trifluoroacetic acid.

[0015] Preferably, the coordination regulator includes benzoic acid, acetic acid and trifluoroacetic acid.

[0016] The combination of benzoic acid, acetic acid and trifluoroacetic acid is preferably used as the coordination regulator, and the three have synergistic effect, synergistically regulate the coordination environment of the zirconium cluster, further affect the structure skeleton of the UiO-66-2AO and the adsorption of the uranyl ion.

[0017] Preferably, the molar ratio of the benzoic acid, acetic acid and trifluoroacetic acid is (1-10):(1-10):(1-10).

[0018] The specific point value in the first (1-10) can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.

[0019] The specific point value in the second (1-10) can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.

[0020] The specific point value in the third (1-10) can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.

[0021] Other specific point values within the above numerical ranges can be selected, which will not be described here one by one.

[0022] Preferably, the solvent includes any one or a combination of at least two of water, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0023] Preferably, the molar ratio of the 2,5-dibromoterephthalic acid, zirconium source and coordination regulator is 1:(0.5-1):(5-20).

[0024] The specific point value in (0.5-1) can be 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1, etc.

[0025] The specific point value in (5-20) can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, etc.

[0026] Preferably, the amount ratio of the 2,5-dibromoterephthalic acid and the solvent is 1 g:(60-80) mL.

[0027] The specific point value in (60-80) can be 60, 62, 65, 67, 70, 73, 75, 78 or 80, etc.

[0028] Preferably, the temperature of the reaction is 80-130℃, for example, it can be 80℃, 82℃, 85℃, 87℃, 90℃, 93℃, 95℃, 98℃, 100℃, 110℃, 120℃ or 130℃, etc.; the time is 20-28 h, for example, it can be 20 h, 21 h, 22 h, 23 h, 24 h, 25 h, 26 h, 27 h or 28 h, etc.

[0029] Other specific point values in the above-mentioned numerical ranges can also be selected, which will not be repeated here.

[0030] Preferably, after the reaction in step (1), it further includes the steps of washing and drying.

[0031] Preferably, the reagent for washing includes any one or a combination of at least two of N,N-dimethylformamide, N-methylpyrrolidone, ethanol or water.

[0032] Preferably, the temperature of the drying is 50-90℃, for example, it can be 50℃, 52℃, 55℃, 57℃, 60℃, 63℃, 65℃, 68℃, 70℃, 75℃, 80℃, 85℃ or 90℃, etc.; the time is 6-24 h, for example, it can be 6 h, 7 h, 8 h, 9 h, 10 h, 13 h, 15 h, 17 h, 20 h, 22 h or 24 h, etc.

[0033] Other specific point values in the above-mentioned numerical ranges can also be selected, which will not be repeated here.

[0034] Preferably, in step (2), the cyanylating reagent includes any one or a combination of at least two of cuprous cyanide, sodium cyanide, potassium cyanide or acetone cyanohydrin.

[0035] Preferably, the solvent includes any one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0036] Preferably, the molar ratio of the UiO-66-2Br and the cyanylating reagent is 1:(0.2-0.4).

[0037] The specific point values in (0.2-0.4) can be 0.2, 0.22, 0.25, 0.27, 0.3, 0.33, 0.35, 0.38 or 0.4, etc.

[0038] Preferably, the ratio of the amount of the UiO-66-2Br and the solvent is 1 g:(50-70) mL.

[0039] The specific point values in (50-70) can be 50, 52, 55, 57, 60, 63, 65, 68, or 70, etc.

[0040] Preferably, the temperature of the reaction is 140-170℃, for example, can be 140℃, 142℃, 145℃, 147℃, 150℃, 153℃, 155℃, 158℃, or 170℃, etc.; the time is 10-14 h, for example, can be 10 h, 10.5 h, 11 h, 11.5 h, 12 h, 12.5 h, 13 h, 13.5 h, or 14 h, etc.

[0041] Other specific point values in the above-mentioned numerical ranges can be selected, which will not be repeated here.

[0042] Preferably, after the reaction in step (2), it further includes the steps of washing and drying.

[0043] Preferably, the reagent for washing includes any one or a combination of at least two of N-methyl pyrrolidone, strong acid or water;

[0044] Preferably, the temperature of drying is 50-90℃, for example, can be 50℃, 52℃, 55℃, 57℃, 60℃, 63℃, 65℃, 68℃, 70℃, 75℃, 80℃, 85℃, or 90℃, etc.; the time is 6-24 h, for example, can be 6 h, 7 h, 8 h, 9 h, 10 h, 13 h, 15 h, 17 h, 20 h, 22 h, or 24 h, etc.

[0045] Other specific point values in the above-mentioned numerical ranges can be selected, which will not be repeated here.

[0046] Preferably, in step (3), the hydroxylamine salt includes hydroxylamine nitrate, hydroxylamine sulfate and hydroxylamine oxalate.

[0047] Preferably, hydroxylamine nitrate, hydroxylamine sulfate and hydroxylamine oxalate are combined for the preparation of UiO-66-2AO, and the three have a synergistic effect, synergistically regulate the structural framework of UiO-66-2AO, and enhance the adsorption of uranyl ions.

[0048] Preferably, the molar ratio of hydroxylamine nitrate, hydroxylamine sulfate and hydroxylamine oxalate is (1-5):(1-7):(1-8).

[0049] The specific point values in (1-5) can be 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3, 3.5, 4, 4.5, or 5, etc.

[0050] The specific point value in (1-7) can be 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3, 4, 5, 6, or 7, etc.

[0051] The specific point value in (1-8) can be 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3, 4, 5, 6, 7, or 8, etc.

[0052] Other specific point values within the above-mentioned numerical ranges can also be selected, which will not be repeated here.

[0053] Preferably, the basic reagent includes any one or a combination of at least two of triethylamine, pyridine, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, or ammonia.

[0054] Preferably, the solvent includes any one or a combination of at least two of methanol, ethanol, or water.

[0055] Preferably, the molar ratio of the hydroxylamine salt, the basic reagent, and the UiO-66-2CN is (0.7-1.5):(0.5-2):1.

[0056] The specific point value in (0.7-1.5) can be 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, or 1.5, etc.

[0057] The specific point value in (0.5-2) can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5, 1.7, or 2, etc.

[0058] Preferably, the amount ratio of the UiO-66-2CN and the solvent is 1 g:(60-120) mL.

[0059] The specific point value in (60-120) can be 60, 62, 65, 67, 70, 73, 75, 78, 80, 90, 100, 110, or 120, etc.

[0060] Preferably, the reaction is carried out under an inert gas atmosphere.

[0061] Preferably, the temperature of the reaction is 65-85℃, for example, it can be 65℃, 67℃, 70℃, 73℃, 75℃, 78℃, 80℃, 82℃, or 85℃, etc.; and the time is 14-28 h, for example, it can be 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 22 h, 25 h, or 28 h, etc.

[0062] Other specific point values within the above-mentioned numerical ranges can also be selected, which will not be repeated here.

[0063] Preferably, after the reaction in step (3), the reaction further comprises a step of washing and drying.

[0064] Preferably, the washing reagent comprises any one or a combination of at least two of methanol, ethanol, acetone or water.

[0065] Preferably, the drying temperature is 50-90℃, for example, 50℃, 52℃, 55℃, 57℃, 60℃, 63℃, 65℃, 68℃, 70℃, 75℃, 80℃, 85℃ or 90℃, etc.; and the drying time is 6-24 h, for example, 6 h, 7 h, 8 h, 9 h, 10 h, 13 h, 15 h, 17 h, 20 h, 22 h or 24 h, etc.

[0066] Other specific point values within the above-mentioned numerical ranges can be selected, which will not be repeated here.

[0067] Preferably, in step (3), the reaction comprises a first-stage reaction and a second-stage reaction.

[0068] The temperature of the first-stage reaction is 65-73℃, for example, 65℃, 65.5 h, 66℃, 66.5 h, 67℃, 67.5 h, 68℃, 68.5 h, 69℃, 69.5 h, 70℃, 71℃, 72℃ or 73℃, etc.; and the time is 14-20 h, for example, 14 h, 14.5 h, 15 h, 15.5 h, 16 h, 16.5 h, 17 h, 17.5 h, 18 h, 18.5 h, 19 h, 19.5 h or 20 h, etc.

[0069] The temperature of the second-stage reaction is 78-85℃, for example, 78℃, 78.5 h, 79℃, 79.5 h, 80℃, 80.5 h, 81℃, 82℃, 83℃, 84℃ or 85℃, etc.; and the time is 24-28 h, for example, 24 h, 24.5 h, 25 h, 25.5 h, 26 h, 26.5 h, 27 h, 27.5 h or 28 h, etc.

[0070] Other specific point values within the above-mentioned numerical ranges can be selected, which will not be repeated here.

[0071] Preferably, the two-stage reaction in step (3) is performed under specific parameters to synergistically control the coordination connection process of various groups, thereby affecting the structural framework of UiO-66-2AO and the adsorption of uranyl ions.

[0072] In a second aspect, the present application provides a functionalized metal organic framework UiO-66-2AO prepared by the method of the first aspect.

[0073] In a third aspect, the present application provides a use of the amidoamine functionalized metal organic framework UiO-66-2AO as described in the second aspect in adsorption of uranyl ions.

[0074] Preferably, the pH value of the uranyl ion adsorption environment is 3-8, for example, can be 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8, etc.

[0075] Other specific point values in the above numerical range can also be selected, which will not be described here.

[0076] Compared with the prior art, the present application has the following beneficial effects:

[0077] The present application breaks through the limitation of the existing single functional group adsorption, and constructs a unique synergistic adsorption mechanism by introducing a double amidoamine group. In this mechanism, a double amidoamine unit can act as a special "chelating pocket" for a uranyl ion. Two adjacent amidoamine groups coordinate with a uranyl ion through the nitrogen and oxygen atoms thereon, forming an integrated structure with high structural stability and containing two five-membered chelating rings. The binding affinity for uranyl ions is significantly improved, and excellent structural stability and ion selectivity are maintained in a wide pH range and complex ion environment, realizing efficient separation of rare earth ions and uranyl ions. BRIEF DESCRIPTION OF DRAWINGS

[0078] Figure 1 X-ray diffraction analysis chart of UiO-66-2Br, UiO-66-2CN and UiO-66-2AO prepared in Example 1;

[0079] Figure 2 Fourier transform infrared spectrum of UiO-66-2Br, UiO-66-2CN and UiO-66-2AO prepared in Example 1;

[0080] Figure 3 Nitrogen adsorption-desorption curve and pore size distribution chart of UiO-66-2AO prepared in Example 1;

[0081] Figure 4 Scanning electron microscope analysis chart of UiO-66-2Br, UiO-66-2CN, UiO-66-2AO prepared in Example 1 and UiO-66-Br, UiO-66-CN, UiO-66-AO prepared in Comparative Example 1;

[0082] Figure 5 Adsorption capacity chart of UiO-66-2AO prepared in Example 1 and UiO-66-AO prepared in Comparative Example 1 at different pH values;

[0083] Figure 6 Distribution coefficient plots of different metal ions adsorbed by UiO-66-2AO prepared in Example 1 and UiO-66-Br, UiO-66-CN, UiO-66-AO prepared in Comparative Example 1;

[0084] Figure 7 Adsorption isotherm plot of uranyl ion by UiO-66-2AO prepared in Example 1. DETAILED DESCRIPTION

[0085] In order to further clarify the technical means adopted by the present application and its effects, the technical solutions of the present application will be further described below in combination with the preferred embodiments of the present application, but the present application is not limited in the scope of the embodiments.

[0086] Unless otherwise specified in the embodiments, the techniques or conditions are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. Unless otherwise specified, the reagents or instruments used are all conventional products that can be commercially available through regular channels.

[0087] Example 1

[0088] The present embodiment provides a preparation method of amine oxime functionalized metal organic framework, which comprises:

[0089] (1) 1 mmol 2,5-dibromoterephthalic acid, 0.8 mmol zirconium chloride, 5 mmol benzoic acid, 5 mmol acetic acid and 5 mmol trifluoroacetic acid are mixed in N,N-dimethylformamide (wherein the amount ratio of 2,5-dibromoterephthalic acid and N,N-dimethylformamide is 1 g:70 mL), and reacted at 120°C for 24 h. After the reaction is completed, the solid is collected, washed with N,N-dimethylformamide for 3 times, and then dried at 60°C for 12 h to obtain UiO-66-2Br.

[0090] (2) 1 mmol UiO-66-2Br and 0.3 mmol cuprous cyanide are mixed in N-methylpyrrolidone (wherein the amount ratio of UiO-66-2Br and N-methylpyrrolidone is 1 g:60 mL), and reacted at 150°C for 12 h. After the reaction is completed, the solid is collected, washed with N-methylpyrrolidone, 0.1 M hydrochloric acid and water in sequence, each reagent is washed for 3 times, and then dried at 60°C for 12 h to obtain UiO-66-2CN.

[0091] (3) 1 mmol UiO-66-2CN, 0.3 mmol hydroxylamine nitrate, 0.5 mmol hydroxylamine sulfate, 0.5 mmol hydroxylamine oxalate and 1 mmol triethylamine were mixed in anhydrous ethanol (wherein the amount ratio of UiO-66-2CN and anhydrous ethanol was 1 g:90 mL), and first reacted at 69°C for 17 h and then reacted at 81°C for 26 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected, washed with 50 vol% ethanol aqueous solution for 3 times, and then dried at 60°C for 12 h to obtain UiO-66-2AO.

[0092] Example 2

[0093] The present example provides a preparation method of an amidoamine functionalized metal organic framework, the method comprising:

[0094] (1) 1 mmol 2,5-dibromoterephthalic acid, 1 mmol zirconium chloride, 8 mmol benzoic acid, 6 mmol acetic acid and 6 mmol trifluoroacetic acid were mixed in N,N-dimethylformamide (wherein the amount ratio of 2,5-dibromoterephthalic acid and N,N-dimethylformamide was 1 g:80 mL), and reacted at 130°C for 20 h. After the reaction was completed, the solid was collected, washed with N,N-dimethylformamide for 3 times, and then dried at 50°C for 24 h to obtain UiO-66-2Br.

[0095] (2) 1 mmol UiO-66-2Br and 0.4 mmol cuprous cyanide were mixed in N-methylpyrrolidone (wherein the amount ratio of UiO-66-2Br and N-methylpyrrolidone was 1 g:70 mL), and reacted at 170°C for 10 h. After the reaction was completed, the solid was collected, washed with N-methylpyrrolidone, 0.1 M hydrochloric acid and water in sequence, each reagent for 3 times, and then dried at 50°C for 24 h to obtain UiO-66-2CN.

[0096] (3) 1 mmol UiO-66-2CN, 0.5 mmol hydroxylamine nitrate, 0.7 mmol hydroxylamine sulfate, 0.3 mmol hydroxylamine oxalate and 2 mmol triethylamine were mixed in anhydrous ethanol (wherein the amount ratio of UiO-66-2CN and anhydrous ethanol was 1 g:120 mL), and first reacted at 65°C for 20 h and then reacted at 85°C for 24 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected, washed with 50 vol% ethanol aqueous solution for 3 times, and then dried at 50°C for 24 h to obtain UiO-66-2AO.

[0097] Example 3

[0098] The present example provides a preparation method of an amidoamine functionalized metal organic framework, the method comprising:

[0099] (1) 1 mmol 2,5-dibromoterephthalic acid, 0.5 mmol zirconium chloride, 2 mmol benzoic acid, 1 mmol acetic acid and 2 mmol trifluoroacetic acid were mixed in N,N-dimethylformamide (wherein the amount ratio of 2,5-dibromoterephthalic acid and N,N-dimethylformamide was 1 g:60 mL), and reacted at 80°C for 28 h. After the reaction was completed, the solid was collected, washed with N,N-dimethylformamide 3 times, and then dried at 90°C for 6 h to obtain UiO-66-2Br.

[0100] (2) 1 mmol UiO-66-2Br and 0.2 mmol cuprous cyanide were mixed in N-methylpyrrolidone (wherein the amount ratio of UiO-66-2Br and N-methylpyrrolidone was 1 g:50 mL), and reacted at 140°C for 14 h. After the reaction was completed, the solid was collected, washed with N-methylpyrrolidone, 0.1 M hydrochloric acid and water in this order, each for 3 times, and then dried at 90°C for 6 h to obtain UiO-66-2CN.

[0101] (3) 1 mmol UiO-66-2CN, 0.2 mmol hydroxylamine nitrate, 0.3 mmol hydroxylamine sulfate, 0.2 mmol hydroxylamine oxalate and 0.5 mmol triethylamine were mixed in anhydrous ethanol (wherein the amount ratio of UiO-66-2CN and anhydrous ethanol was 1 g:60 mL), and reacted at 73°C for 14 h and then at 78°C for 28 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected, washed with 50 vol% aqueous ethanol 3 times, and then dried at 90°C for 6 h to obtain UiO-66-2AO.

[0102] Example 4

[0103] This example provides a preparation method of an amidoamine-functionalized metal organic framework, which is different from Example 1 only in that, in step (3), “first reacted at 69°C for 17 h, and then reacted at 81°C for 26 h” is replaced by “first reacted at 75°C for 12 h, and then reacted at 75°C for 30 h”, and the rest of the raw materials and steps remain unchanged.

[0104] Example 5

[0105] This example provides a preparation method of an amidoamine-functionalized metal organic framework, which is different from Example 1 only in that, in step (3), “first reacted at 69°C for 17 h, and then reacted at 81°C for 26 h” is replaced by “first reacted at 62°C for 23 h, and then reacted at 88°C for 20 h”, and the rest of the raw materials and steps remain unchanged.

[0106] Example 6

[0107] The embodiment provides a preparation method of an amine oxime functionalized metal organic framework, which is different from the embodiment 1 only in that in the step (3), "firstly reacting at 69 DEG C for 17 h, and then reacting at 81 DEG C for 26 h" is replaced by "firstly reacting at 81 DEG C for 26 h, and then reacting at 69 DEG C for 17 h", and the rest of raw materials and steps remain unchanged.

[0108] Embodiment 7

[0109] The embodiment provides a preparation method of an amine oxime functionalized metal organic framework, which is different from the embodiment 1 only in that in the step (3), "firstly reacting at 69 DEG C for 17 h, and then reacting at 81 DEG C for 26 h" is replaced by "reacting at 75 DEG C for 43 h", and the rest of raw materials and steps remain unchanged.

[0110] Embodiment 8

[0111] The embodiment provides a preparation method of an amine oxime functionalized metal organic framework, which is different from the embodiment 1 only in that in the step (3), no hydroxylamine sulfate is added, and the reduced amount is proportionally distributed into hydroxylamine nitrate and hydroxylamine oxalate, and the rest of raw materials and steps remain unchanged.

[0112] Embodiment 9

[0113] The embodiment provides a preparation method of an amine oxime functionalized metal organic framework, which is different from the embodiment 1 only in that in the step (3), no hydroxylamine sulfate is added, and the reduced amount is proportionally distributed into hydroxylamine nitrate and hydroxylamine oxalate, and the rest of raw materials and steps remain unchanged.

[0114] Embodiment 10

[0115] The embodiment provides a preparation method of an amine oxime functionalized metal organic framework, which is different from the embodiment 1 only in that in the step (3), no hydroxylamine oxalate is added, and the reduced amount is proportionally distributed into hydroxylamine nitrate and hydroxylamine sulfate, and the rest of raw materials and steps remain unchanged.

[0116] Embodiment 11

[0117] The embodiment provides a preparation method of an amine oxime functionalized metal organic framework, which is different from the embodiment 1 only in that in the step (3), "0.3 mmol hydroxylamine nitrate, 0.5 mmol hydroxylamine sulfate, 0.5 mmol hydroxylamine oxalate" is replaced by "1.3 mmol hydroxylamine hydrochloride", and the rest of raw materials and steps remain unchanged.

[0118] Embodiment 12

[0119] The present example provides a preparation method of an amidoamine functionalized metal organic framework, which is only different from the example 1 in that in step (1), the benzoic acid is not added, and the reduced amount is proportionally distributed into the acetic acid and trifluoroacetic acid, and the remaining raw materials and steps remain unchanged.

[0120] Example 13

[0121] The present example provides a preparation method of an amidoamine functionalized metal organic framework, which is only different from the example 1 in that in step (1), the acetic acid is not added, and the reduced amount is proportionally distributed into the benzoic acid and trifluoroacetic acid, and the remaining raw materials and steps remain unchanged.

[0122] Example 14

[0123] The present example provides a preparation method of an amidoamine functionalized metal organic framework, which is only different from the example 1 in that in step (1), the trifluoroacetic acid is not added, and the reduced amount is proportionally distributed into the benzoic acid and acetic acid, and the remaining raw materials and steps remain unchanged.

[0124] Example 15

[0125] The present example provides a preparation method of an amidoamine functionalized metal organic framework, which is only different from the example 1 in that in step (1), the “5 mmol benzoic acid, 5 mmol acetic acid and 5 mmol trifluoroacetic acid” is replaced by “15 mmol formic acid”, and the remaining raw materials and steps remain unchanged.

[0126] Comparative Example 1

[0127] The present comparative example provides a preparation method of an amidoamine functionalized metal organic framework, which comprises:

[0128] (1) 1 mmol 2-bromoterephthalic acid, 0.8 mmol zirconium chloride, 5 mmol benzoic acid, 5 mmol acetic acid and 5 mmol trifluoroacetic acid are mixed in N,N-dimethylformamide (wherein the amount ratio of 2-bromoterephthalic acid and N,N-dimethylformamide is 1 g:70 mL), and reacted at 120°C for 24 h. After the reaction is completed, the solid is collected, washed with N,N-dimethylformamide for 3 times, and then dried at 60°C for 12 h to obtain UiO-66-Br.

[0129] (2) 1 mmol UiO-66-Br and 0.3 mmol cuprous cyanide were mixed in N-methylpyrrolidone (the ratio of UiO-66-Br to N-methylpyrrolidone was 1 g: 60 mL), and reacted at 150 °C for 12 h. After the reaction was completed, the solid was collected and washed successively with N-methylpyrrolidone, 0.1 M hydrochloric acid, and water, three times with each reagent. Then it was dried at 60 °C for 12 h to obtain UiO-66-CN.

[0130] (3) 1 mmol UiO-66-CN, 0.3 mmol hydroxylamine nitrate, 0.5 mmol hydroxylamine sulfate, 0.5 mmol hydroxylamine oxalate and 1 mmol triethylamine were mixed in anhydrous ethanol (the ratio of UiO-66-CN to anhydrous ethanol was 1 g:90 mL). The mixture was reacted at 69 °C for 17 h under a nitrogen atmosphere, followed by a reaction at 81 °C for 26 h. After the reaction was completed, the solid was collected, washed three times with 50 vol% ethanol aqueous solution, and then dried at 60 °C for 12 h to obtain UiO-66-AO.

[0131] Test Example 1

[0132] X-ray diffraction (XRD) analysis was performed on the UiO-66-2Br, UiO-66-2CN, and UiO-66-2AO prepared in Example 1. Figure 1 As shown, the XRD patterns of UiO-66-2Br and UiO-66-2CN are almost identical, and basically correspond to the simulated spectrum of the metal-organic framework (UiO-66) generated by the reaction of terephthalic acid and zirconium chloride. This indicates that the UiO-66 series of metal-organic frameworks were successfully synthesized, and the main framework structure remained intact during the subsequent synthesis and modification process. The XRD pattern of UiO-66-2AO shows no obvious diffraction peaks, indicating that the crystallinity of the material weakens after ammonium oxime treatment, and the material transforms into an amorphous state. The ammonium oxime group is larger than the cyano and bromine functional groups, generating huge steric hindrance within the limited pore size, leading to Zr-O bond breakage and framework collapse.

[0133] Test Example 2

[0134] Fourier transform infrared spectroscopy (FTIR) was performed on the UiO-66-2Br, UiO-66-2CN, and UiO-66-2AO prepared in Example 1. Figure 2 As shown, UiO-66-2Br at 724 cm⁻¹ -1 The peak at 2235 cm⁻¹ is a characteristic peak associated with the -Br stretching vibration. This peak disappears after cyanoylation modification and reappears at 2235 cm⁻¹. -1The characteristic peak attributed to the C≡N stretching vibration appears at 2260 cm-1, which is weakened after the amidoxime modification. The new peaks at 1022 cm-1 and 902 cm-1 appear due to the bending vibration of C-NH2 and the stretching vibration of N-O, indicating the successful introduction of the amidoxime group. -1 and 902 cm -1 -1, which indicates the successful introduction of the amidoxime group.

[0135] Test Example 3

[0136] The nitrogen adsorption-desorption curve and pore size distribution of the UiO-66-2AO prepared in Example 1 were tested. As shown in Figure 3 , the adsorption / desorption isotherms of the UiO-66-2AO are all type III curves, and the specific surface area of the UiO-66-2AO is 28.1872 m 2 / g, and the average pore size is 34.3155 nm, indicating that the mesoporous characteristics of the material provide conditions for the entry of uranyl ions into the material. The specific surface area of the UiO-66-2AO is greatly different from the specific surface area of the UiO-66, which is 1360 m 2 / g, which is related to the decrease in crystallinity shown by the XRD, and the change in specific surface area is due to the change in crystal structure and the introduction of larger functional groups in the post-modification process.

[0137] Test Example 4

[0138] The scanning electron microscope (SEM) analysis of the UiO-66-2Br, UiO-66-2CN, UiO-66-2AO prepared in Example 1 and the UiO-66-Br, UiO-66-CN, UiO-66-AO prepared in Comparative Example 1 was performed. As shown in Figure 4 , the UiO-66-Br and the UiO-66-2Br metal-organic framework material have the typical octahedral morphology of the UiO-66, and the uniform size and consistent shape indicate that the material is successfully prepared. After the cyanation modification, the morphology of part of the octahedral particles changes, and the size and shape start to differ, and the morphology change is aggravated after the amidoxime modification. The introduction of the larger cyan functional group and the amidoxime group on the surface of the material makes the surface of the material no longer smooth.

[0139] Test Example 5

[0140] A U(Ⅵ) solution with initial concentration of 20 ppm was prepared, and the pH value was adjusted to 3, 4, 5, 6, 6.5, 7 and 8 by adding 1 M aqueous sodium hydroxide solution or 1 M aqueous hydrochloric acid solution. 2 mg of UiO-66-2AO prepared in Example 1 or UiO-66-AO prepared in Comparative Example 1 was added to 20 mL of U(Ⅵ) solution with different pH values. After oscillation at 25℃ for 12 h at 180 rpm, 3 mL of samples before and after adsorption were taken, filtered using a 0.22 μm mixed cellulose (MCE) membrane, and the concentration of uranium was determined using an inductively coupled plasma optical emission spectrometer (ICP-OES).

[0141] As shown in Figure 5 , the pH value is an important factor affecting the adsorption process, and hydrogen ions not only affect the form of U(Ⅵ) in the solution, but also affect the surface charge of the adsorbent. When the pH is lower than 5, the surface of the amine oxime functionalized material is positively charged, repelling UO2 2+ hydrated cations, and the adsorption of uranium by UiO-66-2AO and UiO-66-AO is almost negligible. When the pH value is greater than 5, the adsorption capacity increases sharply, and UiO-66-2AO can even quantitatively remove uranyl in aqueous solution at pH 5-8, indicating that UiO-66-2AO can be an ideal material for adsorbing uranyl under weak acidic or weak basic conditions.

[0142] Test Example 6

[0143] 2 mg of UiO-66-2AO prepared in Example 1 or UiO-66-Br, UiO-66-CN, UiO-66-AO prepared in Comparative Example 1 was taken, and 20 mL of uranyl ions and other rare earth ions (Lu 3+ , Y 3+ , La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ and Yb 3+In a mixed solution of 10 ppm of each ion, the pH of the system was adjusted to 6.5 with 1 M sodium hydroxide aqueous solution. After shaking at 180 rpm for 12 h at 25 °C, the solution was filtered through a 0.22 μm mixed cellulose (MCE) membrane. The concentrations of various metal ions in the filtrate were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), and the adsorption capacity and distribution coefficient Kd of the material for different metal ions were calculated.

[0144] like Figure 6 As shown, the selectivity of the metal-organic framework for uranyl ions is significantly enhanced after modification with a methylamine oxime group. The distribution coefficient of UiO-66-AO is 3561.53 mL / g, which is 14 times higher than that of UiO-66-Br (241.16 mL / g) and more than twice that of UiO-66-CN (1666.57 mL / g). This indicates that the methylamine oxime group has better selectivity for uranyl ions than the bromide and cyanide groups. UiO-66-2AO containing bismethylamine oxime substituents has more uranium adsorption sites, and its partition coefficient is more than twice that of the monosubstituted material UiO-66-AO.

[0145] Test Example 7

[0146] Adsorption capacity is a core indicator for evaluating the performance of adsorbent materials, determining the total amount of target uranyl ions that a unit mass of adsorbent material can capture. Two mg of UiO-66-2AO prepared in Example 1 was added to 50 mL of solutions containing different initial uranium concentrations (6, 15, 30, 60, 90, and 120 ppm). The pH of the system was adjusted to 6.5 with 1 M sodium hydroxide aqueous solution. After shaking at 180 rpm for 12 h at 25°C, 3 mL of the sample solution was taken and filtered through a 0.22 μm mixed cellulose (MCE) membrane. The concentration of uranium in the filtrate was determined by inductively coupled plasma optical emission spectrometry (ICP-OES).

[0147] like Figure 7 As shown, the isothermal adsorption experiment of the material for uranium did not exhibit a saturation plateau, and the adsorption capacity continued to increase with the initial concentration. When the initial uranium concentration was 120 ppm, the equilibrium concentration of UiO-66-2AO prepared in Example 1 was 58.092 ppm, and the equilibrium adsorption capacity reached 1343.7 mg / g, which far exceeded that of other reported metal-organic framework uranyl adsorbent materials.

[0148] The equilibrium adsorption amount of the UiO-66-2AO prepared in Examples 2-15 at the initial uranium concentration of 120 ppm was detected by the same method as above. As shown in Table 1, from Examples 4-7, it can be seen that the two-stage reaction of the amidoxime modification, the synergistic regulation of the coordination connection process of each group under specific parameters, affects the structural framework of the UiO-66-2AO and the adsorption of the uranyl ion. From Example 11, it can be seen that the type of hydroxylamine salt affects the structural framework of the UiO-66-2AO and the adsorption of the uranyl ion. From Examples 8-10, it can be seen that hydroxylamine nitrate, hydroxylamine sulfate and hydroxylamine oxalate have a synergistic effect, synergistically regulating the structural framework of the UiO-66-2AO and enhancing the adsorption of the uranyl ion. From Example 15, it can be seen that the type of coordination regulator affects the structural framework of the UiO-66-2AO and the adsorption of the uranyl ion. From Examples 12-14, it can be seen that benzoic acid, acetic acid and trifluoroacetic acid have a synergistic effect, synergistically regulating the coordination environment of the zirconium cluster, further affecting the structural framework of the UiO-66-2AO and enhancing the adsorption of the uranyl ion.

[0149] Table 1

[0150]

[0151] The present application is described by the above examples to illustrate the preparation method of the amidoxime functionalized metal organic framework, the product and the application thereof, but the present application is not limited to the above examples, that is, it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

[0152] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0153] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined by any suitable method without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combination methods.

Claims

1. A method of preparing an amido-hydroxamic acid functionalized metal-organic framework, characterized in that, The method comprises: (1) mixing 2,5-dibromoterephthalic acid, a zirconium source and a coordination regulator in a solvent, reacting to obtain a metal-organic framework UiO-66-2Br; (2) mixing the UiO-66-2Br and a cyanation reagent in a solvent, reacting to obtain a metal-organic framework UiO-66-2CN; (3) mixing a hydroxylamine salt, an alkaline reagent and the UiO-66-2CN in a solvent, reacting to obtain an amidoxime-functionalized metal-organic framework UiO-66-2AO; The hydroxylamine salt comprises any one or a combination of at least two of hydroxylamine nitrate, hydroxylamine sulfate or hydroxylamine oxalate.

2. The method of claim 1, wherein, In step (1), the zirconium source comprises any one or a combination of at least two of zirconium chloride, zirconium oxychloride, zirconyl nitrate or zirconium acetate; Preferably, the coordination regulator comprises any one or a combination of at least two of benzoic acid, acetic acid or trifluoroacetic acid; Preferably, the coordination regulator comprises benzoic acid, acetic acid and trifluoroacetic acid; Preferably, the molar ratio of the benzoic acid, acetic acid and trifluoroacetic acid is (1-10):(1-10):(1-10); Preferably, the solvent comprises any one or a combination of at least two of water, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone; Preferably, the molar ratio of the 2,5-dibromoterephthalic acid, the zirconium source and the coordination regulator is 1:(0.5-1):(5-20); Preferably, the usage ratio of the 2,5-dibromoterephthalic acid and the solvent is 1 g:(60-80) mL; Preferably, the temperature of the reaction is 80-130℃ and the time is 20-28 h.

3. The method according to claim 1 or 2, characterized in that, In step (1), after the reaction, the method further comprises steps of washing and drying; Preferably, the reagent for washing comprises any one or a combination of at least two of N,N-dimethylformamide, N-methylpyrrolidone, ethanol or water; Preferably, the temperature of drying is 50-90℃ and the time is 6-24 h.

4. The method according to any one of claims 1-3, characterized in that, In step (2), the cyanation reagent comprises any one or a combination of at least two of cuprous cyanide, sodium cyanide, potassium cyanide or acetone cyanohydrin; Preferably, the solvent comprises any one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide or N-methylpyrrolidone; Preferably, the molar ratio of the UiO-66-2Br and the cyanation reagent is 1:(0.2-0.4); Preferably, the usage ratio of the UiO-66-2Br and the solvent is 1 g:(50-70) mL; Preferably, the temperature of the reaction is 140-170℃ and the time is 10-14 h.

5. The method according to any one of claims 1 to 4, characterized in that, In step (2), after the reaction, the method further comprises steps of washing and drying; Preferably, the reagent for washing comprises any one or a combination of at least two of N-methylpyrrolidone, a strong acid or water; Preferably, the temperature of drying is 50-90℃ and the time is 6-24 h.

6. The method according to any one of claims 1-5, characterized in that, In step (3), the hydroxylamine salt comprises hydroxylamine nitrate, hydroxylamine sulfate and hydroxylamine oxalate; Preferably, the molar ratio of the hydroxylamine nitrate, hydroxylamine sulfate and hydroxylamine oxalate is (1-5):(1-7):(1-8); Preferably, the basic reagent comprises any one or a combination of at least two of triethylamine, pyridine, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or ammonia; Preferably, the solvent comprises any one or a combination of at least two of methanol, ethanol or water; Preferably, the molar ratio of the hydroxylamine salt, the basic reagent and UiO-66-2CN is (0.7-1.5):(0.5-2):1; Preferably, the amount ratio of the UiO-66-2CN and the solvent is 1 g:(60-120) mL; Preferably, the reaction is carried out under an inert gas atmosphere; Preferably, the temperature of the reaction is 65-85℃ and the time is 14-28 h.

7. The method according to any one of claims 1 to 6, characterized in that, In step (3), the reaction further comprises a washing and drying step after the reaction is completed; Preferably, the washing reagent comprises any one or a combination of at least two of methanol, ethanol, acetone or water; Preferably, the drying temperature is 50-90℃ and the time is 6-24 h.

8. The method according to any one of claims 1 to 7, characterized in that, In step (3), the reaction comprises a first stage reaction and a second stage reaction; The temperature of the first stage reaction is 65-73℃ and the time is 14-20 h; The temperature of the second stage reaction is 78-85℃ and the time is 24-28 h.

9. The amidoxy-functionalized metal organic framework UiO-66-2AO prepared by the method of any one of claims 1-8.

10. The use of the amidoxy-functionalized metal organic framework UiO-66-2AO of claim 9 in adsorbing uranyl ions.

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