A metal organic framework material, a preparation method and application thereof

Abstract

The application discloses a metal organic framework material and 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-thiophene dicarboxylic acid in N,N-dimethylformamide to prepare a 2,5-thiophene dicarboxylic acid solution; 2) mixing the aluminum sulfate solution and the 2,5-thiophene dicarboxylic acid solution, then performing a solvothermal reaction, and then performing product separation and purification, so that the metal organic framework material is obtained. The metal organic framework material has the advantages of large specific surface area, large pore volume, low surface polarity and low cost, high selectivity for furfural and large adsorption capacity, can realize high-selectivity and rapid screening of furfural and pentose in sugar solution, and has good cycle stability, and has a very wide application prospect in sugar solution purification.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of furfural separation, and particularly relates to a metal-organic framework material and a preparation method and application thereof. BACKGROUND

[0002] Furfural is an important platform chemical, which is mainly used as a raw material in plastic, chemical, pharmaceutical and other industries, and its demand has been growing. Furfural is usually produced from biomass raw materials rich in hemicellulose through hydrolysis and dehydration (biomass raw materials are first catalytically hydrolyzed to produce pentose, and then the pentose is dehydrated and cyclized to produce furfural). The concentration of furfural in the reaction solution obtained by this method is very low (0.1wt%-6.0wt%), and it is difficult to separate and purify furfural. The processes for separating furfural mainly include distillation, stripping, adsorption, liquid-liquid extraction and the like. These methods are mostly energy-intensive methods, and often require complex operation processes, thereby leading to energy saving and economy of furfural separation. Selective adsorption is a more promising method for separating furfural, and has attracted widespread attention from researchers. At present, researchers have used resins, activated carbon, zeolites and other adsorbents to remove furfural from aqueous solution. However, these adsorbents have low adsorption capacity for furfural (the adsorption capacity is usually less than 300mg / g), and long equilibrium time (several hours to several days) and poor cycle stability, which are difficult to fully meet the requirements of practical application.

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

[0004] The present application aims to provide a metal-organic framework material and a preparation method and application thereof.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A preparation method of a metal-organic framework material comprises the following steps:

[0007] 1) Dissolving aluminum sulfate in water to prepare an aluminum sulfate solution, and dissolving 2,5-thiophenedicarboxylic acid (H2TDC) in N,N-dimethylformamide to prepare a 2,5-thiophenedicarboxylic acid solution;

[0008] 2) Mixing the aluminum sulfate solution and the 2,5-thiophenedicarboxylic acid solution, then performing a solvothermal reaction, and then performing product separation and purification to obtain the metal-organic framework material.

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

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

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

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

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

[0014] Preferably, the solvothermal reaction in step 2) is performed at a temperature of 120℃-140℃, and the reaction time is 24 h-40 h.

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

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

[0017] An adsorbent comprising the above metal organic framework material.

[0018] Use of the above metal organic framework material for selectively adsorbing furfural in a 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 application: The metal organic framework material of the present application can be tightly combined with furfural through intermolecular forces and π-π interactions, and since its pore size is slightly smaller than that of pentose, the force on pentose is weak, 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 it has a high furfural adsorption capacity and can effectively adsorb and separate furfural.

[0021] Beneficial effects of the present application: The metal organic framework material of the present application has a large specific surface area, a large pore volume, a low surface polarity, and a low cost, and has a high selectivity for furfural and a large adsorption capacity, can realize high-selectivity and rapid screening of furfural and pentose in a sugar solution, and has good cycle stability, and has a very broad application prospect in sugar solution purification.

[0022] Specifically:

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

[0024] 2) The metal organic framework material of the present application has a significant separation effect on a furfural and pentose mixed system, and the maximum adsorption amount of furfural in the mixed solution can reach 424.6 mg / g, and more than 98% of furfural can be adsorbed and separated, while pentose is hardly adsorbed, so that high selectivity and rapid screening of furfural and pentose can be achieved, and the adsorption performance is still good after 5 cycles. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0027] Figure 3 is the xylose-furfural two-component competitive adsorption curve.

[0028] Figure 4 is the arabinose-furfural two-component competitive adsorption curve.

[0029] Figure 5 is the three-component competitive adsorption column chart. DETAILED DESCRIPTION

[0030] The present application will be further explained and described below in conjunction with specific examples.

[0031] Examples:

[0032] A metal organic framework material is prepared by the following method:

[0033] 1) 5.95 g (8.93 mmol) of Al2(SO4)3·18H2O is 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 is 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 into a reaction kettle for stirring and refluxing at 135°C for 24h. The product was washed with anhydrous ethanol for 3 times, and then placed in an oven for drying at 80°C for 6h to obtain the metal-organic framework material (three batches of metal-organic framework materials were prepared according to the above operation, and were recorded as MIL-53-TDC-1, MIL-53-TDC-2 and MIL-53-TDC-3 in sequence).

[0035] Performance test:

[0036] 1) The nitrogen adsorption-desorption isotherm curves of the metal-organic framework materials (MIL-53-TDC-1, MIL-53-TDC-2 and MIL-53-TDC-3) in the examples are shown in Figure 1 , and the pore size distribution diagrams are shown in Figure 2 .

[0037] It can be known from Figure 1 and Figure 2 that the BET specific surface area of the metal-organic framework material is 400m 2 / g~480m 2 / g, the pore volume is 0.30cm 3 / g~0.45cm 3 / g, and the pore size is It is illustrated that the metal-organic framework material has large specific surface area and large pore volume.

[0038] 2) Xylose-furfural two-component static adsorption kinetics experiment: 60mg of the metal-organic framework material (MIL-53-TDC-1) in the examples was added into a transparent sample bottle with a volume of 5mL, and then 2mL of xylose-furfural mixed aqueous solution with the concentration of 20mg / mL was added. After being covered with a sealing cover, the sample bottle was placed for stirring adsorption at 24°C, and the stirring speed was 200r / min. After stirring for 5min, 10min, 30min, 60min and 180min, the adsorption liquid was filtered by a syringe with a 0.22μm 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, and the xylose-furfural two-component competitive adsorption curve is shown in Figure 3 .

[0039] It can be known from Figure 3 that furfural is rapidly adsorbed by the metal-organic framework material in about the first 5min, and reaches adsorption equilibrium in about 30min. The adsorption amount of furfural is 278.6mg / g, the adsorption amount of xylose is 5.8mg / g, and the subsequent adsorption amount is almost unchanged.

[0040] 3) Static adsorption kinetics experiment of arabinose-furfural two components: 60 mg of metal organic framework material (MIL-53-TDC-1) in the example was added into a transparent sample bottle with a volume of 5 mL, and then 2 mL of arabinose-furfural mixed aqueous solution with a concentration of 20 mg / mL of arabinose and furfural was added, and then a sealing cover was covered and placed at 24°C for stirring adsorption. The stirring speed was 200 r / min. After stirring for 5 min, 10 min, 30 min, 60 min and 180 min, the adsorption liquid was filtered by a syringe 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, and the arabinose-furfural two-component competitive adsorption curve obtained is shown in Figure 4 .

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

[0042] 4) Static adsorption performance experiment of xylose-furfural two components: 30 mg of metal organic framework material (MIL-53-TDC-1) in the example was added into a transparent sample bottle with a volume of 5 mL, and then 1 mL of xylose-furfural mixed aqueous solution with a concentration of 2.5 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL and 40 mg / mL of xylose and furfural was added, and then a sealing cover was covered and placed at 24°C for stirring for 30 min to reach adsorption equilibrium. The stirring speed was 200 r / min. Then the adsorption liquid was filtered by a syringe 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.

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

[0044] 5) Static adsorption performance experiment of arabinose-furfural two-component system: 30 mg of the metal-organic framework material (MIL-53-TDC-1) in the examples was added into a transparent sample bottle with a volume of 5 mL, 1 mL of an arabinose-furfural mixed aqueous solution with a concentration of 2.5 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL, and 40 mg / mL of arabinose and furfural was added, and then a sealing cover was used to cover it and placed in a 24°C environment for stirring for 30 min to reach adsorption equilibrium, the stirring speed was 200 r / min, the adsorption liquid was filtered by using a syringe with a 0.22 μm water filter, and the clear liquid was quantitatively analyzed by using high performance liquid chromatography, and each experiment was accompanied by two sets of parallel experiments.

[0045] Test results: when the initial concentration was 40 mg / mL, the maximum adsorption amount of furfural was 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 part of the water molecules, so that the concentration of arabinose in the solution after adsorption was higher than the initial concentration, thereby making the adsorption amount negative); when the initial concentration was 2.5 mg / mL, the maximum adsorption rate of furfural was 98.6%.

[0046] 6) Static adsorption isotherm experiment of xylose-furfural two-component system: 30 mg of the metal-organic framework material (MIL-53-TDC-1) in the examples was added into a transparent sample bottle with a volume of 5 mL, 1 mL of a xylose-furfural mixed aqueous solution 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 of xylose and furfural was added, and then a sealing cover was used to cover it and placed in a 24°C, 40°C, and 60°C environment for stirring for 30 min to reach adsorption equilibrium, the stirring speed was 200 r / min, the adsorption liquid was filtered by using a syringe with a 0.22 μm water filter, and the clear liquid was quantitatively analyzed by using high performance liquid chromatography, and each experiment was accompanied by two sets of parallel experiments.

[0047] Test results: the adsorption isotherm was fitted by using the Langmuir equation, and the reaction enthalpy change was calculated by using the Van't Hoff isothermal equation to obtain ΔH = -4.23 kJ / mol for the adsorption of furfural in the xylose-furfural system, the negative enthalpy change meets the exothermic reaction condition, and the enthalpy change value is small, so the metal-organic framework material is easy to regenerate.

[0048] 7) The static adsorption isotherm experiment of the arabinose-furfural two-component system: 30 mg of the metal-organic framework material (MIL-53-TDC-1) in the examples is added into a transparent sample bottle with a volume of 5 mL, 1 mL of an arabinose-furfural mixed aqueous solution with the concentrations of arabinose and furfural both being 2.5 mg / mL, 5 mg / mL, 7.5 mg / mL, 10 mg / mL, 15 mg / mL, and 20 mg / mL is added, a sealing cover is used to cover the sample bottle, and then the sample bottle is placed at 24℃, 40℃, and 60℃ respectively for stirring for 30 min to reach adsorption equilibrium, the stirring speed is 200 r / min, the adsorption solution is filtered by using a syringe with a 0.22 μm water filter, and the clear solution is subjected to quantitative analysis by using high performance liquid chromatography, and each experiment is accompanied by 2 sets of parallel experiments.

[0049] Test results: The adsorption isotherm is fitted by using the Langmuir equation, the reaction enthalpy change of the adsorption of furfural in the arabinose-furfural system is calculated by using the Van't Hoff isothermal equation, ΔH = -2.83 kJ / mol, the enthalpy change is negative, which meets the exothermic reaction condition, and the enthalpy change value is small, so the metal-organic framework material is easy to regenerate.

[0050] 8) The static circulation experiment of the xylose-furfural two-component system: 30 mg of the metal-organic framework material (MIL-53-TDC-1) in the examples is added into a transparent sample bottle with a volume of 5 mL, 1 mL of a xylose-furfural mixed aqueous solution with the concentrations of xylose and furfural both being 40 mg / mL is added, a sealing cover is used to cover the sample bottle, and then the sample bottle is placed at 24℃ for stirring for 30 min to reach adsorption equilibrium, the stirring speed is 200 r / min, the metal-organic framework material is washed with anhydrous ethanol for 3 times for desorption regeneration, each time of washing is placed for 10 min to allow the solvent to be fully exchanged, then the metal-organic framework material is transferred to an oven for drying at 80℃ for 6 h, and then the above experiment conditions are continuously repeated for adsorption separation, the circulation is used for 5 times, the adsorption solution is filtered by using a syringe with a 0.22 μm water filter, and the clear solution (the adsorption solution with different circulation times) is subjected to quantitative analysis by using high performance liquid chromatography.

[0051] Test results: After the metal-organic framework material is circulated for 5 times, the adsorption amount of furfural can still reach 89.6% of the initial adsorption amount, which indicates that the metal-organic framework material has good circulation stability.

[0052] 9) Static circulation experiment of arabinose-furfural two-component: 30 mg of the metal-organic framework material (MIL-53-TDC-1) in the examples is added into a transparent sample bottle with a volume of 5 mL, 1 mL of an arabinose-furfural mixed aqueous solution with a concentration of 40 mg / mL of arabinose and furfural is added, and then a sealing cover is used to cover it, and it is placed in a 24℃ environment for stirring for 30 min to reach adsorption equilibrium, the stirring speed is 200 r / min, the metal-organic framework material is washed with anhydrous ethanol for 3 times for desorption and regeneration, each time is placed for 10 min to make the solvent fully exchange, and then it is transferred to an oven for drying at 80℃ for 6 h, and then the above experimental conditions are continuously repeated for adsorption separation, and the circulation is used for 5 times, then the adsorption liquid is filtered with a syringe equipped with a 0.22 μm water filter, and the clear liquid (adsorption liquid of different circulation times) is quantitatively analyzed by high performance liquid chromatography.

[0053] Test result: the adsorption amount of the metal-organic framework material for furfural can still reach 92.3% of the initial adsorption amount after 5 times of circulation, which indicates that the metal-organic framework material has good circulation stability.

[0054] 10) Static adsorption performance experiment of three components: 30 mg of the metal-organic framework material (MIL-53-TDC-1) in the examples is added into a transparent sample bottle with a volume of 5 mL, 1 mL of a xylose-arabinose-furfural mixed aqueous solution with a concentration of 40 mg / mL of 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 is added, a sealing cover is used to cover it, and then it is placed in a 24℃ environment for stirring for 30 min to reach adsorption equilibrium, the stirring speed is 200 r / min, the adsorption liquid is filtered with a syringe equipped with a 0.22 μm water filter, and the clear liquid is quantitatively analyzed by high performance liquid chromatography, and a three-component competitive adsorption column chart is obtained as shown in Figure 5 .

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

[0056] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement modes, and all shall be included in the protection scope of the present application.

Claims

1. Use of a metal organic framework material for selective adsorption of furfural in a sugar liquor, characterized in that, The metal-organic framework material is made by a preparation method comprising the following steps: 1) dissolving aluminum sulfate in water to form an aluminum sulfate solution, and dissolving 2,5-thiophenedicarboxylic acid in N,N-dimethylformamide to form a 2,5-thiophenedicarboxylic acid solution; 2) mixing the aluminum sulfate solution and the 2,5-thiophenedicarboxylic acid solution, then performing a solvothermal reaction, and then performing product separation and purification to obtain the metal-organic framework material.

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

1.

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

1.

4. Use according to claim 1 or 2, characterized in that: In step 1), the concentration of the aluminum sulfate solution is 0.01-0.2 g / mL.

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

6. Use according to claim 1 or 2, characterized in that: In step 2), the solvothermal reaction is performed at a temperature of 120-140°C, and the reaction time is 24-40 hours.

7. The use according to claim 1, 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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