A mild preparation method and application of nanowire-based MOF

Abstract

The present invention belongs to the field of material preparation technology, and specifically relates to a mild preparation method and application of a nanowire-based MOF. The present invention realizes the in-situ growth of UiO-66-NH2 on slender MnO2 nanowires at room temperature, effectively solving the problem of agglomeration of MOF due to its small size during the adsorption process, reducing the embedding of adsorption sites; and greatly improving the utilization efficiency of adsorption sites in MOF, so that the adsorption capacity of MOF for target substances is significantly improved. The nanowire-based MOF synthesized by the present invention is carried out at room temperature and pressure, which is more energy-saving and environmentally friendly than the traditional high-temperature and high-pressure synthesis method, and the synthesis time is greatly shortened, which simplifies the synthesis process and is conducive to further industrial amplification. It has great commercial promotion value in the separation and purification technology of artesunate.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation, and in particular relates to a mild preparation method and application of a nanowire-based MOF. Background Art

[0002] Malaria is a globally prevalent and widespread parasitic disease that poses a serious threat to people's health and safety. Treating malaria has long been a common goal pursued by medical researchers worldwide. Artemisinin therapy, discovered and studied by Chinese researchers, is highly effective in treating and preventing malaria. Currently, artemisinin and its derivatives are recognized worldwide as the most effective drugs for treating malaria. Artemisinin is an effective antimalarial ingredient extracted from Artemisia annua. Due to its unique peroxide group, it is not only the most effective antimalarial drug but also possesses anti-leukemia and immunomodulatory properties. However, artemisinin has poor water solubility, can only be taken orally, and has poor bioavailability, which affects its therapeutic efficacy. Artemisinin derivatives include artesunate, dihydroartemisinin, artemether, and arteether. Among them, artesunate is obtained by esterification of dihydroartemisinin and succinic anhydride. Compared with other artemisinin derivatives, artesunate has the advantages of high efficiency, rapid effect, low toxicity, low resistance to drug resistance, and can be made into a water-soluble intravenous injection. However, during the synthesis of artesunate, some artemisinin is always present in the product. How to further separate and purify artesunate has aroused the interest of many researchers at home and abroad.

[0003] Researchers have found that the porous structure and large specific surface area of ​​MOFs allow amino groups to form hydrogen bonds with the carboxyl groups in artesunate, enabling UiO-66-NH2 to effectively separate artesunate. However, during the adsorption process, MOFs tend to aggregate, resulting in many adsorption sites being buried, resulting in low adsorption efficiency and low MOF utilization. Solving this problem is crucial for the efficient separation and purification of artesunate. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a mild preparation method and application of nanowire-based MOF. The nanowire-based MOF provided by the present invention can achieve in-situ growth of UiO-66-NH2 on MnO2 nanowires at room temperature.

[0005] The present invention provides a mild preparation method for nanowire-based MOF, which comprises:

[0006] (1) K2SO4, K2S2O8 and MnSO4·H2O were added to the inner container of a high-pressure reactor in sequence, and distilled water was added. After mixing, the mixture was reacted in an oven and cooled to obtain coarse MnO2 nanowires. After washing with hot water and violently stirring, MnO2 nanowires were prepared.

[0007] (2) ZrCl4 is dissolved in a mixed solvent of formic acid and anhydrous ethanol to form a metal solution; NH2-BDC is mixed with anhydrous ethanol, formic acid and pure water, and a ligand solution is obtained by ultrasonication; the MnO2 nanowires obtained in step (1) are placed in the metal solution at room temperature for a first immersion reaction, filtered at normal pressure, and then taken out and placed in the ligand solution for a second immersion reaction; after the reaction is completed, the nanowire-based MOF is rinsed with anhydrous ethanol and filtered under reduced pressure to obtain the nanowire-based MOF.

[0008] Preferably, in step (1), the dosage ratio of K2SO4, K2S2O8, MnSO4·H2O to distilled water is 0.038:0.076:0.038:60 mL-80 mL.

[0009] The temperature of the oven in step (1) is 200°C-220°C, and the reaction time is 96 h-100 h.

[0010] The temperature of the hot water washing in step (1) is 65°C-70°C; the violent stirring is driven by a DC motor at 3000-3500 rpm for 4-6 hours.

[0011] The amount ratio of ZrCl4, formic acid and anhydrous ethanol in the metal solution of step (2) is 1 mmoL: 7-9 mL: 20-25 mL.

[0012] The dosage ratio of NH2-BDC, formic acid, anhydrous ethanol and pure water in the ligand solution of step (2) is 2 mmoL: 7-9 mL: 20-25 mL: 8-10 mL.

[0013] The ultrasonic time in step (2) is 1-1.5 hours, the first immersion reaction time is 1-3 hours, and the second immersion reaction time is 1-4 hours.

[0014] The reduced pressure filtration in step (2) is filtration under a negative pressure of 0.1 MPa.

[0015] In a specific embodiment, the present invention also provides a nanowire-based MOF prepared by the above preparation method.

[0016] In a specific embodiment, the present invention also provides the application of the nanowire-based MOF prepared above in the field of separation and purification of artesunate.

[0017] The present invention achieves in-situ growth of UiO-66-NH2 on elongated MnO2 nanowires at room temperature, effectively resolving the problem of small-sized agglomeration of MOFs during adsorption, reducing the entrapment of adsorption sites, and significantly improving the utilization efficiency of adsorption sites within the MOF, resulting in a significant increase in the MOF's adsorption capacity for target substances. The nanowire-based MOF synthesized in this invention is produced at room temperature and pressure, making it more energy-efficient and environmentally friendly than traditional high-temperature and high-pressure synthesis methods. The synthesis time is significantly reduced, simplifying the synthesis process and facilitating further industrial scale-up. This technology has significant commercial value in the separation and purification of artesunate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a scanning image of the prepared MnO2 nanowires; in the figure, (b) is a 10-fold magnification of (a);

[0019] Figure 2 This is a high-magnification transmission image of the prepared nanowire-based MOF-1 in situ grown on MnO2;

[0020] Figure 3 is the mapping diagram of Mn, N and Zr elements in the prepared nanowire-based MOF-1;

[0021] Figure 4 The following are scans of the prepared nanowire-based MOF-1; (a) is a 10,000-fold magnification, and (b) is a 15,000-fold magnification;

[0022] Figure 5 is a graph showing the adsorption performance of different nanowire-based MOFs prepared in Examples 2-4;

[0023] Figure 6 is a graph showing the adsorption performance of different nanowire-based MOFs prepared in Example 5;

[0024] Figure 7 Graph showing the adsorption performance of different nanowire-based MOFs prepared in Example 6. Implementation Method

[0025] The present invention is further described by the following examples, however, the scope of the present invention is not limited to the following examples. The present invention provides general and / or specific descriptions of the materials and experimental methods used in the experiments. Experimental methods in the following examples where specific conditions are not specified were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The reagents and materials used in the following examples, unless otherwise specified, are commercially available.

[0026] Example 1: Preparation of MnO2 nanowires

[0027] 6.6023 g of K₂SO₄, 20.5215 g of K₂S₂O₄, and 6.6006 g of MnSO₄·H₂O were weighed and added sequentially to the inner container of a reactor. 60 mL of distilled water was then added to the inner container. The solution was homogenized by ultrasonication for 5 minutes and then placed in an oven at 250°C for 96 hours. After the reaction, the mixture was allowed to cool naturally to obtain coarse MnO₂ nanowires. The mixture was then washed 3–5 times with hot water at 65–70°C to remove unreacted raw materials and inorganic impurities. The resulting MnO₂ nanowires were vigorously stirred by a DC motor at 3000 rpm for 4–6 hours. This resulted in uniformly dispersed, elongated MnO₂ nanowires, which were then stored in acetonitrile for later use.

[0028] Figure 1 This is a scanning image of the prepared MnO2 nanowires; in the figure, (b) is a 10-fold magnification of (a). Figure 1 It can be seen that the prepared MnO2 nanowires present a slender linear structure, good monodispersity, relatively uniform dispersion, an aspect ratio of up to 1250:1, and do not aggregate into loose spherical aggregates.

[0029] Example 2: In situ growth of MOF (UiO-66-NH2) on MnO2 nanowires

[0030] (1) Weigh 0.2332 g (1 mmol) of ZrCl4 into a beaker. Mix 7 mL of formic acid (analytical grade) and 20 mL of anhydrous ethanol and add the mixture to the beaker. Ultrasonicate at room temperature to form a uniform metal solution.

[0031] (2) Take 7 mL of formic acid, 20 mL of anhydrous ethanol and 8 mL of pure water and add them to 0.3622 g (2 mmol) of NH2-BDC (2-aminoterephthalic acid). After thorough mixing, ultrasonic treatment is carried out at room temperature for 1 h to obtain a uniform ligand solution.

[0032] (3) The MnO2 nanowires prepared in Example 1 were immersed in the metal solution of step (1) at room temperature for 1 hour, filtered under normal pressure, and then immersed in the ligand solution obtained in step (2) for 4 hours. The solution was rinsed with anhydrous ethanol to remove unreacted organic impurities such as NH2-BDC and filtered under reduced pressure at a negative pressure of 0.1 MPa to obtain a novel MnO2 nanowire-based material. This material was named MOF-1, where 1 represents the amount of ZrCl4 in the metal solution (1 mmoL). The prepared nanowire-based MOF-1 was stored in deionized water for later use.

[0033] Figure 2 This is a high-magnification transmission image of the prepared nanowire-based MOF-1 in situ grown on MnO2; Figure 2As can be seen in the figure, the granular MOF is evenly distributed on the surface of the nanowires, and the in-situ growth effect is good. The prepared nanowire-based MOF can effectively solve the problem of MOF agglomeration during the adsorption process, reduce the embedding of adsorption sites, and improve the utilization rate of adsorption sites and adsorption efficiency.

[0034] Figure 3 is the mapping diagram of Mn, N and Zr elements in the prepared nanowire-based MOF-1; Figure 3 It can be seen that MOF-1 prepared after in situ growth contains Mn, N and Zr elements, indicating that MOF has been successfully grown in situ on MnO2 nanowires.

[0035] Figure 4 The scanned images of the prepared nanowire-based MOF-1 are shown in Figure 1. (a) is a 10,000-fold magnification, and (b) is a 15,000-fold magnification. Figure 4 It can be seen that UiO-66-NH2 (MOF) grows in situ on the MnO2 nanowires, and granular MOF appears clearly on the surface of the nanowires and is distributed relatively evenly. Example

[0036] Nanowire-based MOF-2 with different molar ratios was prepared by referring to the preparation method of MOF-1 in Example 2. The only difference between MOF-2 and MOF-1 was that the amount of ZrCl4 added was changed to 0.4664 g (2 mmol / L). Example

[0037] Nanowire-based MOF-3 with different molar ratios was prepared by referring to the preparation method of MOF-1 in Example 2. The only difference between MOF-3 and MOF-1 was that the amount of ZrCl4 added was changed to 0.6996 g (3 mmol).

[0038] The adsorption performance of each nanowire-based MOF prepared in Examples 2-4 was verified by adding 0.5 g of the nanowire-based MOF to 10 mL of an ethanol solution of 200 mg / L artesunate. The solution was shaken in a water bath at room temperature for 3 h at a shaking rate of 120 rpm. The supernatant was then tested by HPLC to determine the artesunate concentration.

[0039] Figure 5 is the adsorption performance diagram of different nanowire-based MOFs prepared in Examples 2-4; Figure 5 It can be seen that when the molar ratio of ZrCl4 to NH2-BDC is 2:2, the adsorption capacity of the nanowire-based MOF is the largest, reaching 33.88 mg·g -1 . Example

[0040] Referring to the preparation method of MOF-1 in Example 2, different nanowire-based MOFs were prepared by changing only the immersion time in the metal solution in step (3). The only difference from Example 2 was that the immersion time in the metal solution in step (3) was changed from 1 h to 2 h and 3 h, respectively. The prepared nanowire-based MOFs were designated MOF-1-1 and MOF-1-2.

[0041] The adsorption performance of each prepared nanowire-based MOF was verified. Figure 6 is the adsorption performance diagram of different nanowire-based MOFs prepared in Example 5; Figure 6 It can be seen that the adsorption amount of nanowire-based MOF is proportional to the immersion time in the metal solution. When the immersion time in the metal solution is 3 h, the adsorption amount reaches a maximum of 45.78 mg·g -1 . Example

[0042] Referring to the preparation method of MOF-1 in Example 2, different nanowire-based MOFs were prepared by changing only the immersion time in the ligand solution in step (3). The difference from Example 2 was that the immersion time in the ligand solution in step (3) was changed from 4 h to 2 h and 1 h, respectively. The prepared nanowire-based MOFs were designated MOF-1-3 and MOF-1-4, respectively.

[0043] The adsorption performance of each nanowire-based MOF prepared in Example 6 was verified. Figure 7 is the adsorption performance diagram of different nanowire-based MOFs prepared in Example 6; Figure 7 It can be seen that the adsorption amount of the nanowire-based MOF is proportional to the time of immersion in the ligand solution. When the immersion time in the ligand solution is 4 h, the adsorption amount reaches a maximum of 33.84 mg·g -1 .

[0044] A certain amount of nanowire-based MOF was added to the corresponding test solution and shaken in a constant temperature water bath to investigate the effect of different initial concentrations of adsorption solution on the nanowire-based MOF. After the adsorption was completed, the concentration of unadsorbed artemisinin molecules was measured by HPLC, and the adsorption capacity ( Q e , mg / g ), the formula is:

[0045]

[0046] in C 0 (mg / L) and C e (mg / L) are the initial concentration and equilibrium adsorption concentration of artemisinin, respectively. V (mL) and W(mg) are the volume of the solution and the mass of different nanowire-based MOFs, respectively.

[0047] After calculation, when the molar ratio of ZrCl4 to organic ligand is 2:2, the adsorption capacity of the prepared MnO2 nanowire-based MOF for the target compound artesunate is C 0 is 500 mg·L -1 The maximum value can reach 223.52 mg·g -1 . Example

[0048] 6.6023 g of K₂SO₄, 20.5215 g of K₂S₂O₄, and 6.6006 g of MnSO₄·H₂O were weighed and added sequentially to the inner container of a reactor. 80 mL of distilled water was then added to the inner container. The solution was homogenized by ultrasonication for 5 minutes and then placed in an oven at 200°C for 100 hours. After the reaction was complete, the mixture was allowed to cool naturally to obtain coarse MnO₂ nanowires. The mixture was then washed three to five times with hot water at 65–70°C to remove unreacted raw materials and inorganic impurities. The resulting MnO₂ nanowires were vigorously stirred at 3500 rpm for 4 hours using a DC motor. This resulted in uniformly dispersed, elongated MnO₂ nanowires, which were then stored in acetonitrile for later use.

[0049] Weigh 0.2332 g (1 mmol) of ZrCl4 into a beaker. Mix 9 mL of formic acid (analytical grade) and 25 mL of anhydrous ethanol and add them to the beaker. Ultrasonicate at room temperature to form a uniform metal solution.

[0050] 9 mL of formic acid, 25 mL of anhydrous ethanol, and 10 mL of pure water were added to 0.3622 g (2 mmol) of NH2-BDC (2-aminoterephthalic acid). After thorough mixing, the mixture was ultrasonically treated at room temperature for 1.5 h to obtain a uniform ligand solution.

[0051] The prepared MnO2 nanowires were first immersed in the metal solution of step (1) for 3 h at room temperature, filtered at normal pressure and then taken out, and then immersed in the ligand solution obtained in step (2) for 2 h; rinsed with anhydrous ethanol to remove unreacted organic impurities such as NH2-BDC and filtered under reduced pressure to obtain a new MnO2 nanowire base.

[0052] Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without mutual contradiction.

Claims

1. A mild preparation method of nanowire-based MOF, characterized in that: The preparation method comprises: (1) K2SO4, K2S2O8 and MnSO4·H2O were sequentially added to the inner container of a high-pressure reactor, and distilled water was added. After mixing, the mixture was reacted in an oven and cooled to obtain coarse MnO2 nanowires. After washing with hot water and violently stirring, MnO2 nanowires were prepared. (2) dissolving ZrCl4 in a mixed solvent of formic acid and anhydrous ethanol to form a metal solution; mixing NH2-BDC with anhydrous ethanol, formic acid and pure water, and ultrasonically obtaining a ligand solution; placing the MnO2 nanowires obtained in step (1) into the metal solution at room temperature for a first immersion reaction, filtering at normal pressure, taking them out, and placing them into the ligand solution for a second immersion reaction; after the reaction is completed, rinsing with anhydrous ethanol, and filtering under reduced pressure to obtain a nanowire-based MOF; In step (1), the ratio of K2SO4, K2S2O8, MnSO4·H2O to distilled water is 0.038mmoL:0.076mmoL:0.038mmoL:60mL-80mL; the violent stirring is driven by a DC motor at 3000-3500rpm for 4-6h; In step (2), the amount ratio of ZrCl4, formic acid and anhydrous ethanol in the metal solution is 1mmoL:7-9mL:20-25mL; the amount ratio of NH2-BDC, formic acid, anhydrous ethanol and pure water in the ligand solution is 2mmoL:7-9mL:20-25mL:8-10mL.

2. The preparation method according to claim 1, characterized in that The temperature of the oven in step (1) is 200° C.-220° C., and the reaction time is 96 h-100 h.

3. The preparation method according to claim 1, characterized in that The temperature of the hot water washing in step (1) is 65°C-70°C.

4. The preparation method according to claim 1, characterized in that The reduced pressure filtration in step (2) is filtration under a negative pressure of 0.1 MPa.

5. The preparation method according to claim 1, characterized in that The ultrasonic time in step (2) is 1-1.5 hours, the first immersion reaction time is 1-3 hours, and the second immersion reaction time is 1-4 hours.

6. The nanowire-based MOF prepared according to the preparation method according to any one of claims 1 to 5.

7. Application of the nanowire-based MOF prepared by the preparation method according to any one of claims 1 to 5 in the field of separation and purification of artesunate.

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