Co-mof fiber and preparation method and application thereof

Abstract

The application discloses a kind of Co-MOF fibers and its preparation method and application.The preparation method of Co-MOF fiber of the application includes the following steps: 1) the coordination reaction is carried out by dispersing cobalt salt and organic ligand in methanol, and then the solid product is separated, to obtain Co-MOF nano precursor;2) Co-MOF nano precursor is dispersed in water to carry out hydrothermal reaction, and then the solid product is separated, i.e.Co-MOF fiber.The Co-MOF fiber of the application can specifically adsorb vitamin E, and its preparation method is simple, low in energy consumption, good in structure reproducibility, and suitable for large-scale popularization and application.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, specifically to a Co-MOF fiber, its preparation method, and its application. Background Technology

[0002] Vitamin E (VE), also known as tocopherol or prenatal vitamin E, is commonly used as an antioxidant. Vitamin E is soluble in organic solvents such as fats and ethanol, but insoluble in water. It possesses various biological activities, including preventative and therapeutic effects against coronary artery disease and cataracts, and it also has anti-aging effects (by interrupting the chain reaction of free radicals, protecting cell membrane stability, preventing the formation of lipofuscin on the membrane, thus delaying aging; and by maintaining the stability of genetic material and preventing chromosomal structural variations, regulating the body's metabolic activities in an orderly manner, thus delaying aging). Its application prospects are broad. However, currently there is no simple and effective single reagent to extract vitamin E from organic solutions, and there is no way to specifically isolate vitamin E from natural products.

[0003] Therefore, developing a material that can specifically separate vitamin E is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a Co-MOF fiber, its preparation method, and its application.

[0005] The technical solution adopted in this invention is:

[0006] A method for preparing Co-MOF fibers includes the following steps:

[0007] 1) Cobalt salt and organic ligands were dispersed in methanol for coordination reaction. The organic ligands were at least one of 4,4'-dihydroxy-3,3'-biphenyl dicarboxylic acid, 2,5-dihydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid, 5-(3-carboxy-4-hydroxyphenyl)-2-hydroxybenzoic acid, and 4-(4-carboxy-5-hydroxyphenyl)-2-hydroxybenzoic acid. The solid product was then separated to obtain Co-MOF nano precursor.

[0008] 2) The Co-MOF nano precursor is dispersed in water and subjected to a hydrothermal reaction. The solid product is then separated to obtain Co-MOF fibers.

[0009] Preferably, the cobalt salt in step 1) is at least one of cobalt acetate and cobalt nitrate.

[0010] Preferably, the organic ligand in step 1) is one of 4,4'-dihydroxy-3,3'-biphenyldicarboxylic acid and 2,5-dihydroxyterephthalic acid.

[0011] Preferably, the molar ratio of cobalt salt and organic ligand in step 1) is 1:0.9 to 1.1.

[0012] Preferably, the coordination reaction in step 1) is carried out at room temperature for 2 to 6 hours.

[0013] Preferably, the hydrothermal reaction in step 2) is carried out at a temperature of 120℃ to 180℃ for a reaction time of 10h to 72h.

[0014] More preferably, the hydrothermal reaction in step 2) is carried out at a temperature of 120℃~130℃ for a reaction time of 10h~15h.

[0015] A Co-MOF fiber, which is prepared by the above-described method.

[0016] Preferably, the Co-MOF fiber has a length of 10μm to 150μm and a diameter of 20nm to 500nm.

[0017] Preferably, the aspect ratio of the Co-MOF fiber is 200 to 1500.

[0018] A Co-MOF fiber, which is obtained by surface modification of the above-mentioned Co-MOF fiber with sodium aminosulfonate.

[0019] An application of a Co-MOF fiber as described above for the specific adsorption of vitamin E in organic solutions.

[0020] An adsorbent comprising the aforementioned Co-MOF fibers.

[0021] The beneficial effects of this invention are: the Co-MOF fiber of this invention can specifically adsorb vitamin E, and its preparation method is simple, energy consumption is low, and structural reproducibility is good, making it suitable for large-scale promotion and application.

[0022] Specifically, this invention prepares Co-MOF fibers with a diameter of less than 1 μm and an aspect ratio of over 1000 by screening suitable metal salts and organic ligands and strictly controlling the ratio of metal salts to organic ligands using hydrothermal recrystallization. The process is simple, energy-efficient, and produces products with high yield and good structural reproducibility. Furthermore, the surface of the Co-MOF fibers has strong interactions with specific functional groups on vitamin E, enabling selective adsorption of vitamin E in mixed solutions. This can be used for the selective separation of vitamin E from natural products (e.g., the separation and purification of vitamin E from human serum). Attached Figure Description

[0023] Figure 1 This is a SEM image of the Co-MOF nanoprecursor in Example 1.

[0024] Figure 2 This is a SEM image of the Co-MOF fiber in Example 1.

[0025] Figure 3 This is a TEM image of the Co-MOF fiber in Example 1.

[0026] Figure 4 The image shows the XRD patterns of the Co-MOF nanoprecursor and Co-MOF fiber in Example 1.

[0027] Figure 5 The graph shows the test results of the adsorption performance of Co-MOF fiber for different vitamins in Example 1.

[0028] Figure 6 This is a SEM image of the Co-MOF fiber in Example 2.

[0029] Figure 7 This is a SEM image of the Co-MOF fiber in Example 3.

[0030] Figure 8 The image shows the EDS spectrum of the Co-MOF fiber in Example 3. Detailed Implementation

[0031] The present invention will be further explained and described below with reference to specific embodiments.

[0032] Example 1:

[0033] A Co-MOF fiber, the preparation method of which is as follows:

[0034] 1) 0.274 g of cobalt acetate tetrahydrate was stirred and dispersed in 60 mL of anhydrous methanol to prepare a cobalt acetate solution. 0.297 g of 4,4'-dihydroxy-3,3'-biphenyl dicarboxylic acid (DOT2) was stirred and dispersed in 60 mL of anhydrous methanol to prepare a DOT2 solution. The DOT2 solution was then added dropwise to the stirred cobalt acetate solution. After the addition was complete, the mixture was stirred at room temperature for 2 h. The solid was then centrifuged to obtain the Co-MOF nano precursor.

[0035] 2) The Co-MOF nano-precursor was stirred and dispersed in 30 mL of water to prepare a Co-MOF nano-precursor dispersion, which was then transferred to a polytetrafluoroethylene-lined reactor and reacted at 125℃ for 12 h. The solid was filtered and freeze-dried to obtain Co-MOF fibers.

[0036] Performance testing:

[0037] 1) Scanning electron microscope (SEM) images of the Co-MOF nanoprecursor and Co-MOF fiber in this embodiment are shown below. Figure 1 and Figure 2 (a and b represent different magnifications) As shown, the transmission electron microscope (TEM) image of Co-MOF fiber is as follows. Figure 3 As shown.

[0038] Depend on Figure 1 It can be seen that the Co-MOF nano-precursor in this embodiment is an amorphous crystal.

[0039] Depend on Figure 2 It can be seen that the Co-MOF fiber in this embodiment has a length of 50μm to 100μm, a diameter of 20nm to 60nm, and an aspect ratio of up to 1000.

[0040] Depend on Figure 3 It can be seen that the Co-MOF fiber in this embodiment has a high degree of crystallization order, there are defects within the fiber, and there are overlaps between the fibers.

[0041] 2) The X-ray diffraction (XRD) patterns of the Co-MOF nanoprecursor and Co-MOF fiber in this embodiment are shown below. Figure 4 As shown.

[0042] Depend on Figure 4 It can be seen that the structure of the Co-MOF fiber in this embodiment is almost consistent with the theoretically simulated crystal space structure. It exhibits two main diffraction peaks. The peak with 2θ = 8.00° corresponds to the periodic structure along the direction of the MOF hexagonal channel (c-axis), and the peak with 2θ = 12.40° corresponds to the periodic structure along the diameter direction of the MOF channel.

[0043] 3) Prepare a serum simulation solution containing seven vitamins and methylmalonic acid (MMA). The concentrations of each component are as follows: Vitamin A (VA) 566 ng / mL; Vitamin D2 (VD2) 46 ng / mL; Vitamin D3 (VD3) 51 ng / mL; Vitamin E (VE) 13 ng / mL; Vitamin B2 (VB2) 7 ng / mL; Vitamin B5 (VB5) 92 ng / mL; Vitamin B6 (pyridoxal form, VB6(PA)) 76 ng / mL; Methylmalonic acid (MMA) 211 ng / mL. Add 5 mg of Co-MOF fiber to each 1 mL of serum simulation solution, vortex for 5 min, centrifuge, add internal standard to the supernatant, and perform quantitative analysis using liquid chromatography / mass spectrometry. Calculate the concentration of each component in the solution after adsorption by Co-MOF fiber. Then, compare with the initial content of each component in the serum simulation solution to calculate the adsorption rate and retention rate of each component. The test results of the adsorption performance of Co-MOF fiber for different vitamins are as follows: Figure 5 As shown.

[0044] Depend on Figure 5It can be seen that the adsorption effect of the Co-MOF fiber in this embodiment on different vitamins is significantly different, and the adsorption effect on vitamin E is the most obvious, with a supernatant retention rate of only 3.1%, that is, the adsorption rate of vitamin E is about 96.9%. This indicates that the Co-MOF fiber in this embodiment can be used to specifically adsorb vitamin E in organic solutions.

[0045] Example 2:

[0046] A Co-MOF fiber, the preparation method of which is as follows:

[0047] 1) 0.996 g of cobalt acetate tetrahydrate was stirred and dispersed in 90 mL of anhydrous methanol to prepare a cobalt acetate solution. 0.792 g of 2,5-dihydroxyterephthalic acid (hereinafter referred to as DOT1) was stirred and dispersed in 60 mL of anhydrous methanol to prepare a DOT1 solution. The DOT1 solution was then added dropwise to the cobalt acetate solution under stirring. After the addition was complete, the mixture was stirred at room temperature for 2 h. The solid was then collected by centrifugation to obtain the Co-MOF nano precursor.

[0048] 2) The Co-MOF nano-precursor was stirred and dispersed in 30 mL of water to prepare a Co-MOF nano-precursor dispersion, which was then transferred to a polytetrafluoroethylene-lined reactor and reacted at 125℃ for 12 h. The solid was filtered and freeze-dried to obtain Co-MOF fibers.

[0049] Performance testing:

[0050] The SEM image of the Co-MOF fiber in this embodiment is as follows: Figure 6 (a and b represent different magnifications) as shown.

[0051] Depend on Figure 6 It can be seen that the Co-MOF fiber in this embodiment has a diameter of 50nm to 500nm, a length of 100μm or more, and an aspect ratio of 200 to 1000.

[0052] Tests (using the same method as in Example 1) have shown that the Co-MOF fiber in this example can also be used to specifically adsorb vitamin E from organic solutions.

[0053] Example 3:

[0054] A Co-MOF fiber, the preparation method of which is as follows:

[0055] 1) 0.137 g of cobalt acetate tetrahydrate was stirred and dispersed in 50 mL of anhydrous methanol to prepare a cobalt acetate solution, and 0.149 g of 4,4'-dihydroxy-3,3'-biphenyl dicarboxylic acid was stirred and dispersed in 50 mL of anhydrous methanol to prepare a DOT2 solution. The DOT2 solution was then added dropwise to the stirred cobalt acetate solution. After the addition was complete, the mixture was stirred at room temperature for 2 h. The solid was then collected by centrifugation to obtain the Co-MOF nano precursor.

[0056] 2) The Co-MOF nano-precursor was stirred and dispersed in 30 mL of water to prepare a Co-MOF nano-precursor dispersion, which was then transferred to a polytetrafluoroethylene-lined reactor and reacted at 125℃ for 12 h. The solid was centrifuged and added to 30 mL of sodium aminosulfonate (NH2NaSO3) solution with a concentration of 10 mmol / L and pH = 7.0. The mixture was stirred at room temperature for 3 h, allowed to stand for 36 h, and the solid was centrifuged and freeze-dried to obtain Co-MOF fibers (denoted as Co-MOF@NH2SO3).

[0057] Performance testing:

[0058] 1) The SEM image of the Co-MOF fiber in this embodiment is as follows: Figure 7 As shown.

[0059] Depend on Figure 7 It can be seen that the Co-MOF fiber in this embodiment has a diameter of about 20 nm, a length of more than 10 μm, and an aspect ratio of up to 1000. It maintains a one-dimensional morphology that is approximately consistent with the Co-MOF fiber in Example 1.

[0060] 2) The region energy dispersive spectroscopy (EDS) diagram of the Co-MOF fiber in this embodiment is shown below. Figure 8 As shown.

[0061] Depend on Figure 8 It can be seen that the surface of the Co-MOF fiber in this embodiment has a conformal distribution of N and S elements, that is, it is simultaneously modified with amino (-NH2) and sulfonic acid (-SO3) groups.

[0062] Tests (using the same method as in Example 1) have shown that the Co-MOF fiber in this example can also be used to specifically adsorb vitamin E from organic solutions.

[0063] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An application of Co-MOF fiber for the specific adsorption of vitamin E in organic solutions, characterized in that, The Co-MOF fiber is prepared by a method including the following steps: 1) Cobalt salt and organic ligands were dispersed in methanol for coordination reaction. The organic ligands were at least one of 4,4'-dihydroxy-3,3'-biphenyl dicarboxylic acid, 2,5-dihydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid, and 5-(3-carboxy-4-hydroxyphenyl)-2-hydroxybenzoic acid. The solid product was then separated to obtain Co-MOF nano precursor. 2) The Co-MOF nano precursor is dispersed in water and subjected to a hydrothermal reaction. The solid product is then separated to obtain Co-MOF fibers.

2. The application according to claim 1, characterized in that: In step 1), the molar ratio of cobalt salt to organic ligand is 1:0.9 to 1.

1.

3. The application according to claim 1 or 2, characterized in that: Step 1) The coordination reaction is carried out at room temperature for 2 to 6 hours.

4. The application according to claim 1, characterized in that: Step 2) The hydrothermal reaction is carried out at a temperature of 120℃~180℃ for a reaction time of 10h~72h.

5. The application according to claim 1, characterized in that: The Co-MOF fiber has a length of 10μm to 150μm and a diameter of 20nm to 500nm.

6. The application according to claim 1 or 5, characterized in that: The aspect ratio of the Co-MOF fiber is 200 to 1500.

7. The application according to claim 1, characterized in that: The Co-MOF fibers are surface-modified with sodium aminosulfonate.

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