Metal organic framework material as well as preparation method and application thereof

Abstract

The invention discloses a metal organic framework material as well as a preparation method and application thereof. The preparation method of the metal organic framework material comprises the following steps: 1) dissolving aluminum sulfate in water to prepare an aluminum sulfate solution, and dissolving 2, 5-thiophenedicarboxylic acid in N, N-dimethylformamide to prepare a 2, 5-thiophenedicarboxylic acid solution; and 2) mixing an aluminum sulfate solution and a 2, 5-thiophenedicarboxylic acid solution, performing solvothermal reaction, and performing product separation and purification to obtain the metal organic framework material. The metal organic framework material disclosed by the invention is large in specific surface area, large in pore volume, low in surface polarity, low in cost, high in furfural selectivity and large in adsorption capacity, can realize high-selectivity rapid screening of furfural and pentose in a sugar solution, is relatively good in cycling stability, and has a very wide application prospect in the aspect of sugar solution purification.

Description

Technical Field

[0001] The invention relates to the technical field of furfural separation, and in particular to a metal organic framework material and a preparation method and application thereof. Background Art

[0002] Furfural is an important platform chemical, mainly used as a raw material in the plastics, chemical, pharmaceutical and other industries, and its demand has been growing. Furfural is usually made from hemicellulose-rich biomass raw materials through hydrolysis and dehydration (the biomass raw materials are first catalytically hydrolyzed to produce pentose, and the pentose is then dehydrated and cyclized to produce furfural). The concentration of furfural in the reaction solution obtained by this method is very low (the concentration is 0.1wt% to 6.0wt%), and the separation and purification of furfural is difficult. The processes for furfural separation mainly include distillation, stripping, adsorption, liquid-liquid extraction, etc. Most of these methods are energy-intensive methods and often require complex operating procedures, resulting in furfural separation being neither energy-saving nor economical. Selective adsorption is a more promising method for furfural separation and has attracted widespread attention from researchers. At present, researchers have used adsorbents such as resins, activated carbon, and zeolites to remove furfural from aqueous solutions. However, these adsorbents have low adsorption capacity for furfural (the adsorption amount is usually less than 300mg / g), long equilibrium time (several hours to several days), and poor cyclic stability, which makes it difficult to fully meet the requirements of practical applications.

[0003] Therefore, it is of great significance to develop an adsorbent with high selectivity, large adsorption capacity, good cyclic stability and low cost. Summary of the invention

[0004] The purpose of the present invention is to provide a metal organic framework material and a preparation method and application thereof.

[0005] The technical solution adopted by the present invention is:

[0006] A method for preparing a metal organic framework material comprises the following steps:

[0007] 1) Aluminum sulfate was dissolved in water to prepare an aluminum sulfate solution, and 2,5-thiophenedicarboxylic acid (H 2 TDC) was dissolved in N,N-dimethylformamide to prepare a 2,5-thiophenedicarboxylic acid solution;

[0008] 2) The aluminum sulfate solution and the 2,5-thiophenedicarboxylic acid solution are mixed, and then a solvent thermal reaction is carried out, and then the product is separated and purified to obtain a metal organic framework material.

[0009] Preferably, in step 1), the molar ratio of aluminum sulfate to 2,5-thiophenedicarboxylic acid is 0.25 to 4:1.

[0010] Further preferably, in step 1), the molar ratio of aluminum sulfate to 2,5-thiophenedicarboxylic acid is 1.0-1.2:1.

[0011] Preferably, in step 1), the volume ratio of water to N,N-dimethylformamide is 3 to 5:1.

[0012] Preferably, the concentration of the aluminum sulfate solution in step 1) is 0.01 g / mL to 0.2 g / mL.

[0013] Preferably, the concentration of the 2,5-thiophenedicarboxylic acid solution in step 1) is 0.01 g / mL to 0.2 g / mL.

[0014] Preferably, the solvent thermal reaction in step 2) is carried out at a temperature of 120° C. to 140° C., and the reaction time is 24 h to 40 h.

[0015] Preferably, step 2) comprises the following operations: mixing the aluminum sulfate solution and the 2,5-thiophenedicarboxylic acid solution, performing a solvent thermal reaction, washing the product with anhydrous ethanol for multiple times, and then baking in an oven at 70° C. to 90° C. for 5 h to 10 h.

[0016] A metal organic framework material is prepared by the above preparation method.

[0017] An adsorbent comprises the metal organic framework material.

[0018] An application of the metal organic framework material as described above for selectively adsorbing furfural in sugar solution.

[0019] Preferably, the components in the sugar solution include furfural and at least one of glucose, xylose, arabinose, fructose, mannose and 5-hydroxymethylfurfural.

[0020] Principle of the present invention: The metal organic framework material of the present invention can be tightly combined with furfural through intermolecular forces and π-π interactions, and because its pore size is slightly smaller than pentose, the force on pentose is weaker, thereby achieving the effect of screening furfural and pentose. In addition, the metal organic framework material has a large specific surface area and a large pore volume, so that it has a high furfural adsorption capacity and can effectively adsorb and separate furfural.

[0021] The beneficial effects of the present invention are as follows: the metal organic framework material of the present invention has a large specific surface area, a large pore volume, a low surface polarity, and a low cost; it has a high selectivity for furfural and a large adsorption capacity; it can achieve high-selectivity and rapid screening of furfural and pentoses in sugar solution; and it has good cyclic stability, and has a very broad application prospect in sugar solution purification.

[0022] Specifically:

[0023] 1) The metal organic framework material of the present invention has a large specific surface area (BET specific surface area is 400m 2 / g~480m 2 / g), large pore volume (pore volume is 0.30cm 3 / g~0.45cm 3 / g), suitable for high-selectivity and rapid screening of furfural and pentose in sugar solution;

[0024] 2) The metal organic framework material of the present invention has a significant separation effect on the mixed system of furfural and pentoses. The maximum adsorption amount of furfural in the mixed solution can reach 424.6 mg / g, and it can adsorb and separate more than 98% of furfural, while it hardly adsorbs pentoses, and can achieve high-selectivity and rapid screening of furfural and pentoses, and still has good adsorption performance after 5 cycles of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : is the nitrogen adsorption-desorption isotherm curve of the metal organic framework material in the example.

[0026] Figure 2 Graph showing the pore size distribution of the metal organic framework material in the examples.

[0027] Figure 3 This is the competitive adsorption curve of xylose-furfural two components.

[0028] Figure 4 This is the competitive adsorption curve of arabinose-furfural two components.

[0029] Figure 5 This is a bar graph of competitive adsorption of three components. DETAILED DESCRIPTION

[0030] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0031] Example:

[0032] A metal organic framework material, the preparation method of which is as follows:

[0033] 1) 5.95 g (8.93 mmol) of Al 2 (SO 4 ) 3 18H 2 O was dissolved in 50 mL of deionized water to prepare an aluminum sulfate solution (concentration of 0.06 g / mL), and 1.35 g (7.84 mmol) of 2,5-thiophene dicarboxylic acid was dissolved in 12.5 mL of N,N-dimethylformamide to prepare a 2,5-thiophene dicarboxylic acid solution (concentration of 0.11 g / mL);

[0034] 2) The aluminum sulfate solution and the 2,5-thiophenedicarboxylic acid solution were mixed, and then transferred to a reactor and stirred under reflux at 135° C. for 24 h. The product was washed three times with anhydrous ethanol, and then placed in an oven and baked at 80° C. for 6 h to obtain a metal organic framework material (a total of three batches of metal organic framework materials were prepared according to the above operation, and were respectively recorded as MIL-53-TDC-1, MIL-53-TDC-2 and MIL-53-TDC-3).

[0035] Performance Test:

[0036] 1) The nitrogen adsorption-desorption isotherms of the metal organic framework materials (MIL-53-TDC-1, MIL-53-TDC-2 and MIL-53-TDC-3) in the examples are as follows: Figure 1 The pore size distribution diagram is shown in Figure 2 shown.

[0037] Depend on Figure 1 and Figure 2 It can be seen that the BET specific surface area of ​​metal organic framework materials is 400m 2 / g~480m 2 / g, pore volume is 0.30cm 3 / g~0.45cm 3 / g, pore size This indicates that the metal organic framework material of the present invention has a large specific surface area and a large pore volume.

[0038] 2) Xylose-furfural two-component static adsorption kinetics experiment: 60 mg of the metal organic framework material (MIL-53-TDC-1) in the embodiment was added to a transparent sample bottle with a volume of 5 mL, and then 2 mL of a xylose-furfural mixed aqueous solution with a concentration of 20 mg / mL of xylose and furfural was added, and then covered with a sealing cover and placed at 24°C for stirring adsorption at a stirring speed of 200 r / min. After stirring for 5 min, 10 min, 30 min, 60 min and 180 min, the adsorption liquid was filtered with a syringe equipped with a 0.22 μm water filter head, and the clear liquid was quantitatively analyzed by high performance liquid chromatography. Each experiment was accompanied by 2 sets of parallel experiments. The obtained xylose-furfural two-component competitive adsorption curve is shown as follows: Figure 3 shown.

[0039] Depend on Figure 3 It can be seen that furfural is rapidly adsorbed by the metal organic framework material in the first 5 minutes or so, and the adsorption equilibrium is reached in about 30 minutes. The adsorption amount of furfural is 278.6 mg / g, and the adsorption amount of xylose is 5.8 mg / g. The subsequent adsorption amount remains almost unchanged.

[0040] 3) Arabinose-furfural two-component static adsorption kinetics experiment: 60 mg of the metal organic framework material (MIL-53-TDC-1) in the example was added to a transparent sample bottle with a volume of 5 mL, and then 2 mL of an arabinose-furfural mixed aqueous solution with a concentration of 20 mg / mL for both arabinose and furfural was added. The mixture was then covered with a sealing cover and placed at 24°C for stirring adsorption at a stirring speed of 200 r / min. After stirring for 5 min, 10 min, 30 min, 60 min and 180 min, the adsorbed liquid was filtered with a syringe equipped with a 0.22 μm water filter head, and the clear liquid was quantitatively analyzed by high performance liquid chromatography. Two sets of parallel experiments were performed for each experiment. The obtained arabinose-furfural two-component competitive adsorption curve is shown in the figure. Figure 4 shown.

[0041] Depend on Figure 4 It can be seen that furfural is rapidly adsorbed by the metal organic framework material in the first 5 minutes or so, and the adsorption equilibrium is reached in about 30 minutes. The adsorption amount of furfural is 319.5 mg / g, and the adsorption amount of arabinose is 2.3 mg / g. The subsequent adsorption amount remains almost unchanged.

[0042] 4) Experiment on static adsorption performance of xylose-furfural two-component: 30 mg of the metal organic framework material (MIL-53-TDC-1) in the embodiment was added to a transparent sample bottle with a volume of 5 mL, and then 1 mL of a mixed aqueous solution of xylose and furfural with a concentration of 2.5 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL, and 40 mg / mL was added. The mixture was covered with a sealing cap and stirred at 24°C for 30 min to reach adsorption equilibrium. The stirring speed was 200 r / min. The adsorbed liquid was filtered with a syringe equipped with a 0.22 μm water filter, and the clear liquid was quantitatively analyzed by high performance liquid chromatography. Two parallel experiments were performed for each experiment.

[0043] Test results: When the initial concentration was 40 mg / mL, the furfural reached a maximum adsorption capacity of 396.4 mg / g, and the adsorption capacity of xylose was 17.4 mg / g; when the initial concentration was 2.5 mg / mL, the maximum adsorption rate of furfural reached 98.2%.

[0044] 5) Arabinose-furfural two-component static adsorption performance experiment: 30 mg of the metal organic framework material (MIL-53-TDC-1) in the example was added to a transparent sample bottle with a volume of 5 mL, and then 1 mL of arabinose and furfural mixed aqueous solution with concentrations of 2.5 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL, and 40 mg / mL were added. After covering with a sealing cover, it was stirred at 24°C for 30 min to reach adsorption equilibrium. The stirring speed was 200 r / min, and then the adsorbed liquid was filtered with a syringe equipped with a 0.22 μm water filter head, and the clear liquid was quantitatively analyzed by high performance liquid chromatography. Each experiment was accompanied by 2 sets of parallel experiments.

[0045] Test results: When the initial concentration was 40 mg / mL, the furfural reached a maximum adsorption amount of 424.6 mg / g, and the adsorption amount of arabinose was -13.8 mg / g (the negative adsorption amount may be because the metal organic framework material adsorbed some water molecules, resulting in the concentration of arabinose in the solution after adsorption being higher than the initial concentration, thus making the adsorption amount negative); when the initial concentration was 2.5 mg / mL, the maximum adsorption rate of furfural reached 98.6%.

[0046] 6) Xylose-furfural two-component static adsorption isotherm experiment: 30 mg of the metal organic framework material (MIL-53-TDC-1) in the example was added to a transparent sample bottle with a volume of 5 mL, and then 1 mL of a mixed aqueous solution of xylose and furfural with a concentration of 2.5 mg / mL, 5 mg / mL, 7.5 mg / mL, 10 mg / mL, 15 mg / mL, and 20 mg / mL was added. The mixture was covered with a sealing cap and stirred at 24°C, 40°C, and 60°C for 30 min to reach adsorption equilibrium. The stirring speed was 200 r / min. The adsorbed liquid was filtered with a syringe equipped with a 0.22 μm water filter, and the clear liquid was quantitatively analyzed by high performance liquid chromatography. Two parallel experiments were performed for each experiment.

[0047] Test results: The adsorption isotherm was fitted by the Langmuir equation, and the reaction enthalpy change was calculated by the van't Hoff isotherm equation. The ΔH for the adsorption of furfural in the xylose-furfural system was -4.23 kJ / mol. The negative enthalpy change met the exothermic reaction conditions, and the enthalpy change value was small, so the analytical regeneration of the metal organic framework material was relatively easy.

[0048] 7) Arabinose-furfural two-component static adsorption isotherm experiment: 30 mg of the metal organic framework material (MIL-53-TDC-1) in the example was added to a transparent sample bottle with a volume of 5 mL, and then 1 mL of arabinose and furfural mixed aqueous solution with concentrations of 2.5 mg / mL, 5 mg / mL, 7.5 mg / mL, 10 mg / mL, 15 mg / mL, and 20 mg / mL were added. After covering with a sealing cover, the mixture was stirred at 24°C, 40°C, and 60°C for 30 min to reach adsorption equilibrium. The stirring speed was 200 r / min, and the adsorbed liquid was filtered with a syringe equipped with a 0.22 μm water filter head. The clear liquid was quantitatively analyzed by high performance liquid chromatography. Each experiment was accompanied by 2 sets of parallel experiments.

[0049] Test results: The adsorption isotherm was fitted by the Langmuir equation, and the reaction enthalpy change was calculated by the van't Hoff isotherm equation. The ΔH for the adsorption of furfural in the arabinose-furfural system was -2.83 kJ / mol. The negative enthalpy change met the exothermic reaction conditions, and the enthalpy change value was small, so the analytical regeneration of the metal organic framework material was relatively easy.

[0050] 8) Xylose-furfural two-component static cyclic experiment: 30 mg of the metal organic framework material (MIL-53-TDC-1) in the example was added to a transparent sample bottle with a volume of 5 mL, and then 1 mL of a xylose-furfural mixed aqueous solution with a concentration of 40 mg / mL of xylose and furfural was added. The mixture was covered with a sealing cap and stirred at 24°C for 30 min to reach adsorption equilibrium. The stirring speed was 200 r / min. The metal organic framework material was washed with anhydrous ethanol for 3 times for desorption and regeneration. Each washing was allowed to stand for 10 min to allow the solvent to be fully exchanged. The mixture was then transferred to an oven at 80°C and dried for 6 h. The above experimental conditions were repeated for adsorption and separation. The mixture was recycled for 5 times. The adsorbed liquid was filtered using a syringe equipped with a 0.22 μm water filter. The clear liquid (adsorbed liquid of different cycles) was quantitatively analyzed by high performance liquid chromatography.

[0051] Test results: After the metal organic framework material has been circulated for 5 times, the adsorption amount of furfural can still reach 89.6% of the initial adsorption amount, indicating that the metal organic framework material of the present invention has good cyclic stability.

[0052] 9) Arabinose-furfural two-component static cyclic experiment: 30 mg of the metal organic framework material (MIL-53-TDC-1) in the example was added to a transparent sample bottle with a volume of 5 mL, and then 1 mL of an arabinose-furfural mixed aqueous solution with a concentration of 40 mg / mL of arabinose and furfural was added. The mixture was covered with a sealing cap and stirred at 24°C for 30 min to reach adsorption equilibrium. The stirring speed was 200 r / min. The metal organic framework material was washed 3 times with anhydrous ethanol for desorption and regeneration. Each washing was allowed to stand for 10 min to allow the solvent to be fully exchanged. The mixture was then transferred to an oven at 80°C and dried for 6 h. The above experimental conditions were repeated for adsorption and separation. The mixture was recycled 5 times. The adsorbed liquid was filtered using a syringe equipped with a 0.22 μm water filter head. The clear liquid (adsorbed liquid of different cycles) was quantitatively analyzed by high performance liquid chromatography.

[0053] Test results: After the metal organic framework material has been circulated for 5 times, the adsorption amount of furfural can still reach 92.3% of the initial adsorption amount, indicating that the metal organic framework material of the present invention has good cyclic stability.

[0054] 10) Three-component static adsorption performance experiment: 30 mg of the metal organic framework material (MIL-53-TDC-1) in the embodiment was added to a transparent sample bottle with a volume of 5 mL, and then 1 mL of a xylose-arabinose-furfural mixed aqueous solution with a concentration of 40 mg / mL for xylose, arabinose and furfural or a xylose-arabinose-furfural mixed aqueous solution with a concentration ratio of 10 mg / mL: 10 mg / mL: 1 mg / mL was added, and then covered with a sealing cover and stirred at 24°C for 30 min to reach adsorption equilibrium, the stirring speed was 200 r / min, and then the adsorption liquid was filtered with a syringe equipped with a 0.22 μm water filter head, and the clear liquid was quantitatively analyzed by high performance liquid chromatography, and the obtained three-component competitive adsorption bar graph was as shown Figure 5 shown.

[0055] Depend on Figure 5 It can be seen that the metal organic framework material can still achieve the screening effect on pentose and furfural in the three-component system. The adsorption rate of furfural reaches 87% in the system with a concentration ratio of 10 mg / mL:10 mg / mL:1 mg / mL, indicating that the metal organic framework material of the present invention has high selectivity for furfural.

[0056] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a metal organic framework material, characterized in that: The following steps are involved: 1) dissolving aluminum sulfate in water to prepare an aluminum sulfate solution, and dissolving 2,5-thiophene dicarboxylic acid in N,N-dimethylformamide to prepare a 2,5-thiophene dicarboxylic acid solution; 2) The aluminum sulfate solution and the 2,5-thiophenedicarboxylic acid solution are mixed, and then a solvent thermal reaction is carried out, and then the product is separated and purified to obtain a metal organic framework material.

2. The preparation method according to claim 1, characterized in that: In step 1), the molar ratio of aluminum sulfate to 2,5-thiophenedicarboxylic acid is 0.25 to 4:

1.

3. The preparation method according to claim 1 or 2, characterized in that: In step 1), the volume ratio of water to N,N-dimethylformamide is 3 to 5:

1.

4. The preparation method according to claim 1 or 2, characterized in that: Step 1) The concentration of the aluminum sulfate solution is 0.01 g / mL to 0.2 g / mL.

5. The preparation method according to claim 1 or 2, characterized in that: The concentration of the 2,5-thiophenedicarboxylic acid solution in step 1) is 0.01 g / mL to 0.2 g / mL.

6. The preparation method according to claim 1 or 2, characterized in that: Step 2) The solvent thermal reaction is carried out at a temperature of 120° C. to 140° C., and the reaction time is 24 h to 40 h.

7. A metal organic framework material, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6.

8. An adsorbent, characterized in that Comprising the metal organic framework material according to claim 7.

9. Use of the metal organic framework material as claimed in claim 7 for selectively adsorbing furfural in sugar solution.

10. The use according to claim 9, characterized in that: The components in the sugar solution include furfural and at least one of glucose, xylose, arabinose, fructose, mannose and 5-hydroxymethylfurfural.

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