A preparation method of PAN-MOF porous material activated by peroxymonosulfate

Abstract

The present invention provides a method for preparing a PAN-MOF porous material for activating peroxymonosulfate, and relates to the field of preparation of porous materials. The method for preparing a PAN-MOF porous material based on an activated peroxymonosulfate comprises the following steps: A. weighing 4.45g to 8.18g of polyacrylonitrile and pouring it into a 250mL blue-capped reagent bottle, adding 30.0mL of N,N-dimethylformamide, and stirring in a 60°C oil bath until completely dissolved to obtain a solution a; B. weighing 1.35g of ferric chloride hexahydrate and 0.45g of 2-aminoterephthalic acid, adding 10.0mL of N,N-dimethylformamide, and ultrasonically treating until completely dissolved to obtain a solution b. The present invention successfully synthesized a PAN-MOF material with a three-dimensional porous structure by a PAN and sodium chloride pore-forming method. The material can not only effectively activate peroxymonosulfate to degrade a variety of pollutants, but also has significant mechanical strength and cyclic stability. By adjusting the size and sedimentation time of the sodium chloride particles, the pore size of the material is precisely controlled. This makes it easy to separate materials after sewage treatment, significantly shortening material recovery time.

Description

Technical Field

[0001] The present invention relates to the technical field of porous material preparation, and in particular to a method for preparing a PAN-MOF porous material of activated peroxymonosulfate. Background Art

[0002] The preparation method for a peroxymonosulfate-activated PAN-MOF porous material successfully utilized polyacrylonitrile (PAN) and sodium chloride pore formation, combined with a metal-organic framework (NH2-MIL-101(Fe), MOF). The specific steps are as follows: polyacrylonitrile (PAN) powder was weighed and dissolved in dimethylformamide (DMF) to form solution a. Ferric chloride hexahydrate and 2-aminoterephthalic acid were then added to solution b, which was then heated and stirred to react. After the reaction, sodium chloride pore formation was used to generate the porous material. The PAN-MOF porous material was then washed with water and freeze-dried.

[0003] This system has several drawbacks, primarily manifested in the following: The catalyst's cyclic stability is low: After repeated use, the material removal efficiency decreases significantly, particularly the efficiency of quinoline degradation, which drops from 78.8% to 46.3%. This indicates that the catalyst's active sites gradually degrade over time. The material's mechanical strength needs improvement: Although the material maintains a good shape after the reaction, a small amount of debris falls off, potentially affecting its reusability and separation efficiency. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the shortcomings of the existing technology, the present invention provides a method for preparing PAN-MOF porous materials with activated peroxymonosulfate, which solves the problem that Fe-MOF powder is difficult to separate and recover in wastewater treatment.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented by the following technical solution: a method for preparing a PAN-MOF porous material activated with peroxymonosulfate, comprising:

[0008] A. Weigh 4.45g to 8.18g of polyacrylonitrile powder into a 250mL blue-capped reagent bottle. Add 30.0mL of N,N-dimethylformamide and stir in a 60°C oil bath until completely dissolved to obtain solution A.

[0009] B. Weigh 1.35 g of ferric chloride hexahydrate and 0.45 g of 2-aminoterephthalic acid, add 10.0 mL of N,N-dimethylformamide, and sonicate until completely dissolved to obtain solution b;

[0010] C. Add solution b to solution a and stir until evenly mixed;

[0011] D. Place the mixed solution in a sealed oil bath at 110°C and react for 24 hours;

[0012] E. cooling the reaction product naturally to room temperature;

[0013] F. Pour the cooled product into a beaker, evenly add sodium chloride to the surface of the solution, and let it stand overnight for more than 4 hours to allow the sodium chloride to settle;

[0014] G. Soak the evenly distributed material in deionized water and cut it into strips to dissolve the sodium chloride and DMF. Repeat the washing several times until the sodium chloride and DMF are completely washed away.

[0015] H. Place the cleaned material in a freeze drying oven and freeze-dry for 48 hours to obtain a PAN-MOF porous material;

[0016] I. Analyze the pore structure of PAN-MOF porous materials by scanning electron microscopy to ensure that they have a uniformly distributed pore structure;

[0017] J. Characterization of the crystal structure of PAN-MOF porous materials by X-ray diffractometry.

[0018] Preferably, the molecular weight of the polyacrylonitrile powder in step A is 150,000 to ensure that the material has appropriate mechanical strength and pore structure, and the molar ratio of ferric chloride hexahydrate to 2-aminoterephthalic acid in step B is 2:1 to optimize the formation and distribution of MOF.

[0019] Preferably, the reaction temperature in step D is 110° C. and the reaction time is 24 hours to ensure the complete formation of NH 2 -MIL-101(Fe), and the size of the sodium chloride particles added in step F is in the range of 0.1 to 0.5 mm to control the pore size of the porous material.

[0020] Preferably, the natural sedimentation described in step F allows the sodium chloride to fully and evenly settle to the bottom to ensure that the sodium chloride is fully settled and forms uniform pores. The number of deionized water washing in step G is at least 3 times to ensure that the sodium chloride and DMF are completely dissolved and washed.

[0021] Preferably, the freeze-drying temperature in step H is -50°C to ensure the integrity and stability of the material structure. The mechanical strength and cyclic stability of the PAN-MOF porous material are further improved by introducing a cross-linking agent into the pores.

[0022] Preferably, the catalytic efficiency of the PAN-MOF material in the process of catalytic activation of peroxymonosulfate to remove methyl blue remains above 65% after four cycles of use. By introducing transition metal iron into the MOF material, its catalytic activity and mechanical strength are further enhanced.

[0023] Preferably, the pore size of the material is precisely controlled by adjusting the size and sedimentation time of sodium chloride particles. The PAN-MOF porous material is used to remove various organic pollutants in water, including methylene blue, quinoline and oily wastewater.

[0024] Preferably, the PAN-MOF material can recover its activity by simple water washing or ethanol washing after use, thereby extending the service life of the catalyst. The material still maintains high mechanical strength and structural stability after multiple reaction cycles and is suitable for long-term application.

[0025] (3) Beneficial effects

[0026] The present invention provides a method for preparing a PAN-MOF porous material activated with peroxymonosulfate. It has the following beneficial effects:

[0027] The present invention successfully synthesized a PAN-MOF material with a three-dimensional porous structure using a PAN and sodium chloride pore-forming method. This material can not only effectively activate peroxymonosulfate to degrade various pollutants, but also has significant mechanical strength and cyclic stability. By adjusting the size and sedimentation time of sodium chloride particles, the pore size of the material is precisely controlled, which not only improves its catalytic efficiency but also makes the material easy to separate and recycle during use, reducing the problem of loss during use. The introduced cross-linking agent and transition metal further enhance the catalytic activity and mechanical properties of the material, so that it can still maintain a high catalytic effect after multiple cycles of use.

[0028] The PAN-MOF porous material prepared by this method offers advantages such as ease of operation, low production cost, and high recovery efficiency, making it particularly suitable for the removal of organic pollutants from water. Its macroscopic three-dimensional structure facilitates separation after wastewater treatment, significantly shortening material recovery time and extending the life of the catalyst. The material maintains a high catalytic efficiency after multiple cycles, demonstrating great potential for long-term application and is expected to find widespread application in wastewater treatment, environmental remediation, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The following are photos and cross-sectional SEM images of the materials prepared in the present invention;

[0030] Figure 2 is an X-ray diffraction pattern of the PAN-MOF porous material prepared by the present invention;

[0031] Figure 3 The test results of PAN-MOF porous material activated PMS to remove methylene blue, quinoline and oily wastewater;

[0032] Figure 4 The number of cycles for PAN-MOF porous material to activate PMS to remove methyl blue and quinoline;

[0033] Figure 5 This is a comparison chart before and after the removal of methylene blue and oily wastewater by PAN-MOF porous materials. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] Example 1:

[0036] like Figure 1-4 An embodiment of the present invention provides a method for preparing a PAN-MOF porous material of activated peroxymonosulfate, comprising: A. Weighing 4.45 g to 8.18 g of polyacrylonitrile powder into a 250 mL blue-capped reagent bottle, adding 30.0 mL of N,N-dimethylformamide, and stirring in a 60°C oil bath until completely dissolved to obtain solution A. The molecular weight of the polyacrylonitrile powder is 150,000 to ensure that the material has appropriate mechanical strength and pore structure.

[0037] B. Weigh 1.35g of ferric chloride hexahydrate and 0.45g of 2-aminoterephthalic acid, add 10.0mL of N,N-dimethylformamide, and sonicate until completely dissolved to obtain solution b; the molar ratio of ferric chloride hexahydrate to 2-aminoterephthalic acid in this step is 2:1 to optimize the formation and distribution of MOF

[0038] C. Add solution b to solution a and stir until evenly mixed.

[0039] D. The mixed solution was placed in a sealed oil bath at 110° C. and reacted for 24 hours to ensure the complete formation of NH 2 -MIL-101(Fe). The size of the sodium chloride particles added in step F ranged from 0.1 to 0.5 mm to control the pore size of the porous material.

[0040] E. Allow the reaction product to cool naturally to room temperature.

[0041] F. Pour the cooled product into a beaker, add sodium chloride evenly until it is above the solution surface, and let it stand overnight for more than 4 hours to allow the sodium chloride to settle.

[0042] G. Soak the evenly distributed material in deionized water and cut it into strips to dissolve the sodium chloride and DMF. Repeat the washing several times until the sodium chloride and DMF are completely washed away. The number of deionized water washings should be at least 3 times to ensure that the sodium chloride and DMF are completely dissolved and washed away.

[0043] H. The cleaned material was placed in a freeze drying chamber and freeze-dried for 48 hours to obtain PAN-MOF porous material. The freeze-drying temperature was -50°C to ensure the integrity and stability of the material structure. The mechanical strength and cyclic stability of the PAN-MOF porous material were further improved by introducing a cross-linking agent into the pores.

[0044] I. The pore structure of the PAN-MOF porous material was analyzed by scanning electron microscopy to ensure that it has a uniformly distributed porous structure. At the same time, NH2-M IL-101(Fe) presenting regular hexagonal microspindle crystals was fixed on the PAN porous material, further enhancing its catalytic activity and mechanical strength. The pore size of the material was precisely controlled by adjusting the size of the sodium chloride particles and the sedimentation time. The PAN-MOF porous material was used to remove various organic pollutants from water, including methyl blue, quinoline, and oily wastewater. After use, the PAN-MOF material can be restored to its activity by simple water or ethanol washing, extending the service life of the catalyst. The material still maintains high mechanical strength and structural stability after multiple reaction cycles, making it suitable for long-term applications.

[0045] Example 2:

[0046] The crystal structure of PAN-MOF porous materials was characterized by X-ray diffractometer ( Figure 2 ). PAN in the figure was prepared using the same method as the PAN-MOF porous material, but without the addition of ferric chloride hexahydrate and 2-aminoterephthalic acid during the synthesis. The figure shows that PAN has a distinct characteristic peak at 2θ = 16.8°, indicating a hexagonal structure; a small diffraction peak at 2θ = 29.2° confirms an amorphous structure. The figure also shows that the PAN-MOF porous material has the characteristic peaks of PAN, as well as characteristic peaks of NH2-M IL-101(Fe) at 2θ = 9.20°, 10.2°, and 29.3°, confirming the successful synthesis of the PAN-MOF porous material.

[0047] Example 3:

[0048] PAN-MOF porous material activates PMS to remove methylene blue

[0049] To investigate the PMS activation performance of the prepared PAN-MOF porous material, methylene blue was selected as the research object and its removal performance on methylene blue was measured. The test conditions were: 0.1g PAN-MOF porous material, 1mM potassium persulfate (PMS), 100mL of 5mg / L methylene blue solution was added at 25℃ for 3h, the absorbance of the solution was measured, and the concentration was calculated. The removal rate of methylene blue was calculated according to the following formula:

[0050]

[0051] Where C0 is the concentration of methyl blue solution before removal; C t is the concentration of the methylene blue solution after removal.

[0052] Comparative Example 1: Removal of Methyl Blue by PAN-MOF Porous Material Alone

[0053] Different from Example 3, only the PAN-MOF porous material was added, 100 mL of a 5 mg / L methylene blue solution was reacted at 25° C. for 3 h, and the absorbance of the solution was measured.

[0054] Comparative Example 2: Removal of Methyl Blue by PMS Alone

[0055] The difference from Example 3 is that only 1 mM PMS was added, 100 mL of 5 mg / L methylene blue solution was reacted at 25° C. for 3 h, and the absorbance of the solution was measured.

[0056] The test results of the prepared PAN-MOF porous material activating PMS to remove methyl blue are as follows Figure 3 As shown, from Figure 3 It can be seen that after 3 hours of activation of PMS by PAN-MOF porous material, the removal rate of methyl blue is 100%, while the removal rates of PAN-MOF porous material or PMS alone are 11.7% and 11.5%, respectively, indicating that PAN-MOF porous material has a good removal effect on methyl blue after activation of PMS.

[0057] Example 4: PAN-MOF porous material activation of PMS to remove quinoline

[0058] To investigate the activated PMS performance of the prepared PAN-MOF porous material, quinoline removal was determined. The test conditions were: 0.1 g of PAN-MOF porous material was added to 1 mM PMS and reacted with 100 mL of a 10 mg / L quinoline solution at 25°C for 3 hours. The concentration of the solution was determined by HPLC. The quinoline removal rate was calculated according to the following formula:

[0059]

[0060] Where C0 is the concentration of quinoline solution before removal; C t is the concentration of quinoline solution after removal.

[0061] Comparative Example 3: Removal of quinoline by PAN-MOF porous material alone

[0062] Different from Example 4, only the PAN-MOF porous material was added, and 100 mL of a quinoline solution with a mass concentration of 10 mg / L was reacted at 25° C. for 3 h, and the quinoline concentration was measured.

[0063] Comparative Example 4: Removal of quinoline by PMS alone

[0064] The difference from Example 4 is that only 1 mM PMS was added, and 100 mL of a quinoline solution with a mass concentration of 10 mg / L was reacted at 25° C. for 3 h to measure the quinoline concentration.

[0065] The test results of the prepared PAN-MOF porous material activating PMS to remove quinoline are as follows Figure 3 As shown. Figure 3 It can be seen that after PAN-MOF porous material activated PMS removal for 3 hours, the removal rate of quinoline was 78.8%, while the removal rates of separate PAN-MOF porous material or PMS were 30.9% and 22.6%, respectively. This indicates that PAN-MOF porous material activated PMS has a good removal effect on quinoline.

[0066] Example 5: PAN-MOF porous material activated PMS to remove oily wastewater (emulsified oil washing)

[0067] To investigate the activated PMS performance of the prepared PAN-MOF porous material, its removal performance in oily wastewater was determined. The test conditions were: 0.1 g of PAN-MOF porous material, 1 mM PMS, and 100 mL of a 100 mg / L oily wastewater solution were reacted at 25°C for 3 hours. The absorbance of the solution was then measured. The removal efficiency of the oily wastewater was calculated according to the following formula:

[0068]

[0069] Where C0 is the concentration of oily wastewater solution before removal; C t is the concentration of the oily wastewater solution after removal.

[0070] Comparative Example 5: Removal of Oily Wastewater by PAN-MOF Porous Material Alone

[0071] Different from Example 5, only PAN-MOF porous material was added, 100 mL of oily wastewater solution with a mass concentration of 100 mg / L was reacted at 25° C. for 3 h, and the absorbance of the solution was measured.

[0072] Comparative Example 6: Removal of Oily Wastewater by PMS Alone

[0073] The difference from Example 5 is that only 1 mM PMS was added, 100 mL of the oily wastewater solution with a mass concentration of 100 mg / L was reacted at 25° C. for 3 h, and the absorbance of the solution was measured.

[0074] The test results of the prepared PAN-MOF porous material activating PMS to remove oily wastewater are as follows: Figure 3 It can be seen that after 3 hours of PMS removal activated by PAN-MOF porous material, the removal rate of oily wastewater is 71.1%, while the removal rates of PAN-MOF porous material or PMS alone are 29.1% and 22.8%, respectively. This indicates that PAN-MOF porous material has a good removal effect on oily wastewater after PMS activation.

[0075] Depend on Figure 3 The results show that the present invention uses PAN-MOF porous materials to activate PMS, because the active metal sites in NH2-MIL-101(Fe) can more effectively interact with PMS and effectively activate PMS to produce SO4· - , OH and 1 Active substances such as O2 degrade pollutants.

[0076] Example 6: Stability and reproducible practicality assessment

[0077] In order to evaluate the potential of the material in practical applications, after removing methylene blue from the PAN-MOF porous material, the PAN-MOF porous material was taken out with tweezers and washed three times in anhydrous ethanol and water respectively, and then freeze-dried for 24 hours. It was then used in the next cycle experiment (activating PMS to remove methylene blue). The results of the four cycles were: 100%, 94.6%, 73.2%, and 66.8%, respectively.

[0078] In order to evaluate the potential of the material in practical applications, after removing quinoline from the PAN-MOF porous material, the PAN-MOF porous material was taken out with tweezers and washed three times in anhydrous ethanol and water respectively, and then freeze-dried for 24 hours before being used in the next cycle experiment (activating PMS to remove quinoline). Figure 4 It can be seen that the results of four cycles are: 78.8%, 70.5%, 51.2%, and 46.3%.

[0079] Example 7: Comparison of PAN-MOF porous materials before and after removal of methylene blue and oily wastewater,

[0080] from Figure 5 It can be seen that after removing methylene blue, the blue color of the solution faded; after removing the oily wastewater, the solution changed from turbid to clear, and the PAN-MOF porous material was not broken, only a small amount of debris fell off, and the overall shape was the same as before the reaction, indicating that this porous material is strong and not easy to disperse. At the same time, this material is easy to separate and recover after the reaction.

[0081] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a PAN-MOF porous material activated with peroxymonosulfate, characterized in that: include: A. Pour 4.45g~8.18g of polyacrylonitrile powder and 30mL of N,N-dimethylformamide into a 250mL blue-capped reagent bottle and stir in a 60℃ oil bath until completely dissolved to obtain solution a. B. Weigh 1.35 g of ferric chloride hexahydrate and 0.45 g of 2-aminoterephthalic acid, add 10.0 mL of N,N-dimethylformamide, and sonicate until completely dissolved to obtain solution b. C. Add solution b to solution a and stir until evenly mixed; D. Place the mixed solution in a sealed oil bath at 110°C and react for 24 hours; E. cooling the reaction product naturally to room temperature; F. Pour the cooled product into a beaker, evenly add sodium chloride to the surface of the solution, and let it stand overnight for more than 4 hours to allow the sodium chloride to settle; G. Soak the settled material in deionized water and cut it into strips to dissolve the sodium chloride and DMF. Repeat the washing several times until the sodium chloride and DMF are completely washed away. H. Place the cleaned material in a freeze drying oven and freeze-dry for 48 hours to obtain a PAN-MOF porous material; I. Analyze the pore structure of PAN-MOF porous materials by scanning electron microscopy to ensure that they have a uniformly distributed pore structure; J. Characterization of the crystal structure of PAN-MOF porous materials by X-ray diffractometry.

2. The method for preparing a PAN-MOF porous material activated with peroxymonosulfate according to claim 1, characterized in that: The molecular weight of the polyacrylonitrile powder in step A is 150,000 to ensure that the material has appropriate mechanical strength and pore structure. The molar ratio of ferric chloride hexahydrate to 2-aminoterephthalic acid in step B is 2:1 to optimize the formation and distribution of MOF.

3. The method for preparing a peroxymonosulfate activated PAN-MOF porous material according to claim 1, characterized in that: The reaction temperature in step D is 110° C. and the reaction time is 24 hours to ensure the complete formation of NH 2 -MIL-101(Fe). The size of the sodium chloride particles added in step F ranges from 0.1 to 0.5 mm to control the pore size of the porous material.

4. The method for preparing a peroxymonosulfate activated PAN-MOF porous material according to claim 1, characterized in that: The sedimentation described in step F allows the sodium chloride to fully and evenly settle to the bottom to ensure that the sodium chloride is fully settled and forms uniform pores. The number of deionized water washings in step G is at least 3 times to ensure that the sodium chloride and DMF are completely dissolved and washed.

5. The method for preparing a peroxymonosulfate activated PAN-MOF porous material according to claim 1, characterized in that: The freeze-drying temperature in step H is -50°C to ensure the integrity and stability of the material structure. The mechanical strength and cyclic stability of the PAN-MOF porous material are further improved by introducing a cross-linking agent into the pores.

6. The method for preparing a peroxymonosulfate activated PAN-MOF porous material according to claim 1, characterized in that: In the process of catalytic activation of peroxymonosulfate to remove methyl blue, the catalytic efficiency of the PAN-MOF material remains above 65% after four cycles of use. By introducing transition metal iron into the MOF material, its catalytic activity is further enhanced.

7. The method for preparing a peroxymonosulfate activated PAN-MOF porous material according to claim 1, characterized in that: The pore size of the material is precisely controlled by adjusting the size and sedimentation time of sodium chloride particles. The PAN-MOF porous material is used to remove various organic pollutants in water, including methylene blue, quinoline, and oily wastewater.

8. The method for preparing a peroxymonosulfate activated PAN-MOF porous material according to claim 1, characterized in that: The PAN-MOF material can recover its activity through simple water washing or ethanol washing after use, thereby extending the service life of the catalyst. The material still maintains high mechanical strength and structural stability after multiple reaction cycles and is suitable for long-term application.

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