A pyrazole functionalized UiO-66-NH2 and its preparation method and application
Through hydrothermal synthesis and pyrazole functionalization of UiO-66-NH2, the existing adsorbent lacks active sites and low adsorption capacity are solved, and the efficient iodine vapor adsorption effect is achieved, and good stability and reusability are achieved.
Patent Information
- Application Number
- CN202310550633.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-16
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2043-05-16
AI Technical Summary
The existing adsorbents lack active sites when adsorbing iodine steam, resulting in low adsorption capacity, making it difficult to effectively solve the problem of iodine capture in nuclear waste treatment.
UiO-66-NH2 was prepared by hydrothermal synthesis technology, and then pyrazole functionalized it. By reacting with 1-methyl-1-H-pyrazole-5-carboxylic acid, pyrazole functionalized UiO-66-NH2 adsorbent was constructed.
The iodine steam adsorption capacity of the adsorbent is significantly improved, with good stability and reusability, and can achieve iodine steam adsorption equilibrium after 200 minutes at 75°C and reach equilibrium after 24 hours at room temperature.
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Figure CN116622077B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of adsorbents, and in particular to a pyrazole-functionalized UiO-66-NH2 and a preparation method and application thereof. Background Art
[0002] At present, the problems of fossil energy reduction, natural environment deterioration and global warming are becoming increasingly prominent. Therefore, new efficient and clean energy is gradually being developed. Nuclear energy, as a new type of energy, will not emit too much CO2 while generating electricity, which helps to alleviate the global greenhouse effect. Up to now, there are more than 400 nuclear reactors distributed around the world, supplying about 11% of the world's energy. With the development of nuclear energy, the safety of nuclear power plants and the treatment of nuclear waste have always been the forefront of research. Radioactive isotope iodine, as one of the products of fission, is the main product of nuclear waste. The main isotopes include 131 I and 129 I, generally exists in the form of diatomic element iodine (I2) and organic iodide, among which I2 has high volatility and fluidity. Iodine evaporates into the air and can directly enter the human body to produce internal radiation, or contaminate the skin and cause long-term direct damage.
[0003] Among various iodine capture techniques, adsorption method is considered to be a promising approach due to its simplicity, easy operation and low cost, among which activated carbon, zeolite materials, functionalized clays, aerogels and layered double hydroxides have been widely studied. However, these adsorbents exhibit relatively low adsorption capacity due to the lack of active sites in these frameworks. Summary of the invention
[0004] In view of the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a pyrazole-functionalized UiO-66-NH2 and a preparation method and application thereof. The present invention adopts hydrothermal synthesis technology to prepare UiO-66-NH2, and then performs post-modification modification on it to obtain pyrazole-functionalized UiO-66-NH2. The method is simple to operate, the conditions are easy to control, the cost is low, and the prepared MOFs material has excellent adsorption performance, and at the same time has good stability and reusability, which can effectively solve the problems of lack of active sites and low adsorption capacity.
[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0006] The present invention provides a method for preparing pyrazole functionalized UiO-66-NH2, comprising the following steps:
[0007] (1) ZrCl4 and 2-aminoterephthalic acid are added to N,N-dimethylformamide and mixed, and HCl and HAc are added thereto to obtain a mixed solution;
[0008] (2) treating the mixed solution of step (1) with ultrasound, placing it in an autoclave for crystallization, filtering, washing, and drying to obtain a UiO-66-NH2 metal organic framework material;
[0009] (3) adding 1-methyl-1-H-pyrazole-5-carboxylic acid to a thionyl chloride solution for oil bath reaction, and rotary evaporation to obtain colorless oil droplets after the reaction;
[0010] (4) Adding tetrahydrofuran to react the UiO-66-NH2 metal organic framework material obtained in step (2) and the colorless oil droplets obtained in step (3), and adding triethylamine. After the reaction is completed, filtering, washing, and drying to obtain pyrazole functionalized UiO-66-NH2.
[0011] Preferably, the mass volume ratio of ZrCl4, 2-aminoterephthalic acid and N,N-dimethylformamide in step (1) is 20-25 mg:19-20 mg:3-8 mL.
[0012] Preferably, in step (1), the volume ratio of HCl, HAc and N,N-dimethylformamide is 1-2:59-61:300-900, and the concentration of HCl is 36-38%.
[0013] Preferably, in step (2), the ultrasonic time is 10-30 min, the crystallization temperature in the autoclave is 120-140° C., the crystallization time in the autoclave is 20-24 h, and the washing and drying methods are washing three times with N,N-dimethylformamide and methanol respectively, and drying at 130-150° C. for 8-10 h.
[0014] Preferably, in step (3), the mass volume ratio of 1-methyl-1-H-pyrazole-5-carboxylic acid to thionyl chloride solution is 12-30 mg:0.8-1.1 mL, the reaction temperature is 70-80° C., and the reaction time is 10-12 h.
[0015] Preferably, in step (4), the mass volume ratio of UiO-66-NH2 metal organic framework material, tetrahydrofuran and triethylamine is 100-250g:7-9mL:0.3-0.6mL, the reaction temperature is room temperature, the reaction time is 12-14h, and the washing and drying methods are washing three times with N,N-dimethylformamide and methanol respectively, and drying at 100-120°C for 8-10h.
[0016] Another object of the present invention is to protect a pyrazole-functionalized UiO-66-NH2 prepared by any of the above-mentioned preparation methods.
[0017] The third object of the present invention is to protect the use of pyrazole functionalized UiO-66-NH2 prepared by any of the above-mentioned preparation methods in the adsorption of iodine vapor.
[0018] Preferably, the temperature for adsorbing iodine vapor is room temperature or 75° C., and the humidity environment for adsorbing iodine vapor is 26.6-74.9%.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] 1. The present invention adopts low-cost methanol and N,N-dimethylformamide (DMF) as the solvent system and raw materials, adopts hydrothermal synthesis technology to prepare UiO-66-NH2, and composites 1-methyl-1-H-pyrazole-5-carboxylic acid with UiO-66-NH2 to construct a functionalized UiO-66-NH2 adsorbent, which can effectively solve the problems of lack of active sites and low adsorption capacity.
[0021] 2. The adsorbent pyrazole-functionalized UiO-66-NH2 prepared by the present invention is used for the adsorption of harmful substance iodine vapor, and has excellent adsorption performance. At 75°C, the adsorption of iodine vapor reaches equilibrium at 0.865 g / g after 200 minutes; at room temperature, the adsorption capacity of iodine vapor is 0.817 g / g after 24 hours of equilibrium. At 75°C, when the humidity is 26.9±0.3%, 61.4±0.5% and 74±0.9%, respectively, the adsorption capacity of iodine vapor is 0.561 g / g, 0.396 g / g and 0.231 g / g. In addition, the adsorbent has good stability and reusability. After 5 operations, the adsorption rate of iodine vapor can still reach 91.4%. This method provides a new idea for the rational construction of MOF adsorbents to achieve the adsorption of pollutant iodine vapor.
[0022] 3. The preparation process of the present invention is simple, and only the amount of raw materials needs to be adjusted. It has strong operability and is suitable for mass production. The reaction conditions of hydrothermal synthesis are mild and below 150°C. The production process is safe and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 The reaction diagram of the pyrazole functionalized UiO-66-NH2 adsorbent prepared by the present invention;
[0024] Figure 2 The infrared spectra of the adsorbents prepared in Example 1 and Comparative Example 1 of the present invention;
[0025] Figure 3 The nitrogen adsorption-desorption curves of the adsorbents prepared in Example 1 and Comparative Example 1 of the present invention are shown;
[0026] Figure 4 The iodine adsorption capacity of the adsorbent prepared in Example 1 of the present invention and Comparative Example 1 at 75° C.;
[0027] Figure 5The iodine adsorption capacity of the adsorbent prepared in Example 1 of the present invention and Comparative Example 1 at room temperature;
[0028] Figure 6 Iodine adsorption capacity of the adsorbent prepared in Example 1 of the present invention and Comparative Example 1 at 75° C. and under different humidity conditions;
[0029] Figure 7 This is a cyclic performance diagram of the pyrazole functionalized UiO-66-NH2 adsorbent prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0030] The following will combine the data in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0031] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.
[0032] Example 1
[0033] A method for preparing a pyrazole functionalized UiO-66-NH2 adsorbent comprises the following steps:
[0034] (1) 69 mg of ZrCl4 and 54 mg of 2-aminoterephthalic acid were added to 15 mL of N,N-dimethylformamide (DMF), mixed, and stirred to obtain a solution, and then 0.025 mL of concentrated HCl and 1.5 mL of HAc were added thereto to obtain a mixed solution;
[0035] (2) The mixed solution was ultrasonically treated for 30 min to obtain a clear solution, and the solution was transferred to a 25 mL polytetrafluoroethylene reactor. The reactor was subjected to a hydrothermal reaction at 120 ° C for 20 h. After the reaction was completed, the temperature was cooled to room temperature at 10 ° C / h, filtered, washed three times with 5 mL DMF and 5 mL methanol respectively, and dried at 150 ° C for 10 h to obtain a light yellow powder, which is the UiO-66-NH2 metal organic framework material;
[0036] (3) 180 mg of 1-methyl-1-H-pyrazole-5-carboxylic acid was added to 12 mL of thionyl chloride solution, and the mixture was stirred in an oil bath at 80° C. for 10 h. After the reaction was completed, the mixture was cooled and rotary evaporated to obtain colorless oily droplets;
[0037] (4) 100 mg of yellow powder UiO-66-NH2 obtained in (2) and the product obtained in (3) were added to 8 mL of tetrahydrofuran, and 0.5 mL of triethylamine was added, and the reaction was carried out at room temperature for 12 h. After the reaction, a yellow powder was filtered out, washed three times with DMF and methanol respectively, and dried at 120°C for 10 h to obtain a pyrazole-functionalized UiO-66-NH2 adsorbent.
[0038] Example 2
[0039] A method for preparing a pyrazole functionalized UiO-66-NH2 adsorbent comprises the following steps:
[0040] (1) 60 mg of ZrCl4 and 45 mg of 2-aminoterephthalic acid were added to 9 mL of N,N-dimethylformamide (DMF), mixed, and stirred to obtain a solution, and then 0.045 mL of concentrated HCl and 1.75 mL of HAc were added thereto to obtain a mixed solution;
[0041] (2) The mixed solution was ultrasonically treated for 20 min to obtain a clear solution, and the solution was transferred to a 25 mL polytetrafluoroethylene reactor. The reactor was subjected to a hydrothermal reaction at 130 ° C for 22 h. After the reaction was completed, the temperature was cooled to room temperature at 10 ° C / h, filtered, washed three times with 5 mL DMF and 5 mL methanol respectively, and dried at 140 ° C for 8 h to obtain a light yellow powder, which is the UiO-66-NH2 metal organic framework material;
[0042] (3) 375 mg of 1-methyl-1-H-pyrazole-5-carboxylic acid was added to 15 mL of thionyl chloride solution, and the mixture was stirred in an oil bath at 75° C. for 11 h. After the reaction was completed, the mixture was cooled and rotary evaporated to obtain colorless oily droplets;
[0043] (4) 208 mg of yellow powder UiO-66-NH2 obtained in (2) and the product obtained in (3) were added to 8 mL of tetrahydrofuran, and 0.5 mL of triethylamine was added, and the reaction was carried out at room temperature for 13 h. After the reaction, the yellow powder was filtered out and washed three times with DMF and methanol respectively, and dried at 110°C for 9 h to obtain a pyrazole-functionalized UiO-66-NH2 adsorbent.
[0044] Example 3
[0045] A method for preparing a pyrazole functionalized UiO-66-NH2 adsorbent comprises the following steps:
[0046] (1) 75 mg of ZrCl4 and 57 mg of 2-aminoterephthalic acid were added to 24 mL of N,N-dimethylformamide (DMF), mixed, and stirred to obtain a solution, and then 0.05 mL of concentrated HCl and 1.62 mL of HAc were added thereto to obtain a mixed solution;
[0047] (2) The mixed solution was ultrasonically treated for 10 min to obtain a clear solution, and the solution was transferred to a 25 mL polytetrafluoroethylene reactor. The reactor was subjected to a hydrothermal reaction at 140 ° C for 24 h. After the reaction was completed, the temperature was cooled to room temperature at 10 ° C / h, filtered, washed three times with 5 mL DMF and 5 mL methanol respectively, and dried at 130 ° C for 9 h to obtain a light yellow powder, which is the UiO-66-NH2 metal organic framework material;
[0048] (3) 450 mg of 1-methyl-1-H-pyrazole-5-carboxylic acid was added to 16.5 mL of thionyl chloride solution, and the mixture was stirred in an oil bath at 70° C. for 12 h. After the reaction was completed, the mixture was cooled and rotary evaporated to obtain colorless oily droplets;
[0049] (4) Add 250 mg of yellow powder UiO-66-NH2 obtained in (2) and the product obtained in (3) to 8 mL of tetrahydrofuran, and add 0.5 mL of triethylamine, and react at room temperature for 14 h. After the reaction, filter to obtain a yellow powder, wash it three times with DMF and methanol respectively, and dry it at 100 °C for 8 h to obtain a pyrazole-functionalized UiO-66-NH2 adsorbent.
[0050] Comparative Example 1
[0051] A method for preparing a UiO-66-NH2 adsorbent comprises the following steps:
[0052] (1) 69 mg of ZrCl4 and 54 mg of 2-aminoterephthalic acid were added to 15 mL of N,N-dimethylformamide (DMF), mixed, and stirred to obtain a solution, and then 0.025 mL of concentrated HCl and 1.5 mL of HAc were added thereto to obtain a mixed solution;
[0053] (2) The mixed solution was ultrasonically treated for 30 min to obtain a clear solution, which was then transferred to a 25 mL polytetrafluoroethylene reactor. The reactor was subjected to a hydrothermal reaction at 120 °C for 20 h. After the reaction was completed, the temperature was cooled to room temperature at a rate of 10 °C / h, filtered, washed three times with 5 mL DMF and 5 mL methanol, respectively, and dried at 150 °C for 10 h to obtain a light yellow powder, which was the UiO-66-NH2 metal organic framework material.
[0054] Experimental results and analysis
[0055] Figure 1This is a preparation diagram of the pyrazole functionalized UiO-66-NH2 adsorbent prepared by the present invention. The adsorption of iodine vapor by the adsorbent depends on whether the material has good active sites (N, O). The interaction between the lone pair of electrons on the heteroatom and the volatile molecular iodine plays a vital role in improving the affinity of iodine. There are hydrogen bonds (NH...I), halogen bonds (O...I, N...I) and chemical bonds formed by charge transfer (N→I) between the pyrazole functionalized UiO-66-NH2 adsorbent prepared by the present invention and the iodine molecule. Figure 1 It can be seen that the pyrazole-functionalized MOF material, due to the introduction of 1-methyl-1-H-pyrazole-5-carboxylic acid, has a large number of hydrogen bonds and halogen bonds, which greatly improves the adsorption capacity of iodine vapor. In addition, due to the presence of lone pairs of electrons, the nitrogen atoms on the pyrazole ring and amide can form chemical bonds with iodine element through charge transfer, which improves the active sites of the MOF material and has a significant effect on the adsorption capacity of iodine vapor. Therefore, the composite of 1-methyl-1-H-pyrazole-5-carboxylic acid and UiO-66-NH2 metal organic framework material to construct a new MOF material can effectively solve the problems of lack of active sites and low adsorption capacity.
[0056] Figure 2 This is the infrared spectrum of the pyrazole functionalized UiO-66-NH2 adsorbent prepared in Example 1 of the present invention. In the infrared spectrum of UiO-66-NH2, 3453 cm -1 and 3370cm -1 There is an obvious double peak at 1383 cm, which is due to the asymmetric and symmetric stretching vibrations of the amine group. The two peaks in the lower frequency region correspond to the NH bending vibration and CN stretching vibration of aromatic amines (1383 cm -1 and 1256cm -1 ), additional signals were directly observed in the infrared spectrum of functionalized UiO-66-NH2, including the change from double peak to single peak of NH stretching vibration (3357cm -1 ), C=O stretching vibration (1681cm -1 ) and CN stretching vibration (1260cm -1 ), indicating the successful construction of 1-methyl-1-H-pyrazole-5-carboxylic acid and UiO-66-NH2, and the successful synthesis of pyrazole functionalized UiO-66-NH2 adsorbent.
[0057] Figure 3The nitrogen adsorption-desorption curves of Example 1 of the present invention and Comparative Example 1 show that the isotherms of the samples are Type I, which has micropore filling characteristics. When the relative pressure is slightly lower, the adsorption capacity will increase rapidly and become flat before finally reaching the limit, which confirms the presence of micropores in its structure. However, the hysteresis phenomenon observed in pyrazole-functionalized UiO-66-NH2 indicates that this may be due to the presence of pyrazole functionalization, which leads to the generation of additional mesopores.
[0058] 10 mg of the adsorbent prepared in Example 1 and Comparative Example 1 and excess iodine crystals were placed in sample holders respectively. The two sample holders were transferred to a sealed glass container. Then, an adsorption experiment was carried out in the sealed glass container at an ambient pressure of 75°C, which is close to the actual conditions of nuclear fuel reprocessing. The adsorption amount was monitored by recording the change in sample mass over time.
[0059] Figure 4 The iodine adsorption capacity of the adsorbent prepared in Example 1 and Comparative Example 1 of the present invention changes with time at 75°C. Figure 3 It can be seen that the pyrazole-functionalized UiO-66-NH2 adsorbent prepared in Example 1 reaches adsorption equilibrium after 200 min, and the iodine adsorption capacity is 0.865 g / g, which is superior to that of Comparative Example 1 and has excellent adsorption capacity.
[0060] Figure 5 The iodine adsorption capacity of the adsorbent prepared in Example 1 and Comparative Example 1 changes with time at room temperature. When the temperature decreases, the iodine adsorption capacity of Example 1 decreases from 0.865 g / g to 0.817 g / g, and the equilibrium time is extended from 200 min to 24 h. The iodine adsorption capacity of Example 1 is much higher than that of Comparative Example 1.
[0061] Figure 6 To test the iodine capture capacity of Example 1 of the present invention under different humidity conditions, the above experiment was also conducted under high relative humidity conditions generated by saturated salt solutions, which were 26.9±0.3% (magnesium chloride), 61.4±0.5% (potassium iodide) and 74.0±0.9% (sodium chloride), respectively. Under each humidity condition, two sealed glass containers were prepared, and excess iodine crystals, adsorbent and saturated salt solution were placed in one sealed glass container, and only adsorbent was placed in the other group as a blank control group to eliminate the influence of adsorbed water, such as Figure 6 As shown, when the humidity is higher, the adsorption capacity of Example 1 for iodine vapor is lower. When the humidity is 26.9±0.3% (magnesium chloride), 61.4±0.5% (potassium iodide) and 74.0±0.9% (sodium chloride), the adsorption capacity is 0.561g / g, 0.396g / g and 0.231g / g, respectively.
[0062] Figure 7 The cycle performance diagram of the pyrazole functionalized UiO-66-NH2 adsorbent prepared in Example 1 of the present invention is shown in FIG. Figure 7 It can be seen that the pyrazole functionalized UiO-66-NH2 adsorbent prepared in Example 1 has good stability and reusability, and the adsorption capacity of iodine vapor after 5 runs is 91.4% of the original.
[0063] In summary, the present invention adopts hydrothermal synthesis technology to prepare UiO-66-NH2, and then performs post-modification modification on it to obtain pyrazole functionalized UiO-66-NH2. The method is simple to operate, the conditions are easy to control, the cost is low, and the prepared MOFs material has excellent adsorption performance, good stability and reusability, and can effectively solve the problems of lack of active sites and low adsorption capacity.
[0064] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.
[0065] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.
Claims
1. A method for preparing pyrazole functionalized UiO-66-NH2, characterized in that: The following steps are involved: (1) adding ZrCl4 and 2-aminoterephthalic acid to N,N-dimethylformamide and mixing them, and adding HCl and HAc thereto to obtain a mixed solution, wherein the mass volume ratio of ZrCl4, 2-aminoterephthalic acid and N,N-dimethylformamide is 20-25 mg:15-19 mg:3-8 mL, the volume ratio of HCl, HAc and N,N-dimethylformamide is 1-2:58-61:300-900, and the mass concentration of HCl is 36-38%; (2) treating the mixed solution of step (1) with ultrasound and then adding it to a kettle for crystallization, filtering, washing and drying to obtain a UiO-66-NH2 metal organic framework material, wherein the ultrasound time is 10-30 min, the crystallization temperature in the kettle is 120-140° C., the crystallization time in the kettle is 20-24 h, and the washing and drying method is washing with N,N-dimethylformamide and methanol three times each, and drying at 130-150° C. for 8-10 h; (3) adding 1-methyl-1-H-pyrazole-5-carboxylic acid to a thionyl chloride solution for an oil bath reaction, and rotary evaporation to obtain colorless oil droplets after the reaction, the mass volume ratio of 1-methyl-1-H-pyrazole-5-carboxylic acid to thionyl chloride solution is 12-30 mg:0.8-1.1 mL, the reaction temperature is 70-80° C., and the reaction time is 10-12 h; (4) Adding tetrahydrofuran to react the UiO-66-NH2 metal organic framework material obtained in step (2) and the colorless oil droplets obtained in step (3), and adding triethylamine. After the reaction is completed, filtering, washing, and drying to obtain pyrazole functionalized UiO-66-NH2.
2. The method for preparing pyrazole functionalized UiO-66-NH2 according to claim 1, characterized in that: In step (4), the mass volume ratio of UiO-66-NH2 metal organic framework material, tetrahydrofuran and triethylamine is 100-250g:8mL:0.5mL, the reaction temperature is room temperature, the reaction time is 12-14h, and the washing and drying methods are washing three times with N,N-dimethylformamide and methanol respectively, and drying at 100-120°C for 8-10h.
3. A pyrazole-functionalized UiO-66-NH2 prepared by the preparation method according to any one of claims 1 to 2.
4. Use of the pyrazole functionalized UiO-66-NH2 according to claim 3 in adsorbing iodine vapor.
5. The use of pyrazole functionalized UiO-66-NH2 in adsorption of iodine vapor according to claim 4, characterized in that: The temperature for adsorbing iodine vapor is room temperature and 75° C., and the humidity environment for adsorbing iodine vapor is 26.6-74.9%.