Preparation Method of a MIL-101(Fe) Resin Composite Adsorbent, the Resulting Adsorbent and Its Application

Abstract

The present invention discloses a preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps: (1) Pretreating an anion exchange resin; (2) Dissolving ferric trichloride hexahydrate in hydrochloric acid, then adding the anion exchange resin obtained in step (1), stirring, filtering and drying to obtain an iron-loaded resin; (3) Adding the iron-loaded resin to a sodium hydroxide solution, stirring, washing until neutral and then drying; (4) Adding the product obtained in step (3) to a terephthalic acid solution dissolved in N,N-dimethylformamide, stirring, reacting at 80-120 °C, cooling, filtering, washing and drying. The present invention also discloses the composite adsorbent obtained by this preparation method and its application in adsorbing glyphosate in water at a concentration of 1-200 mg / L. The composite adsorbent obtained by the present invention has an increased specific surface area on the basis of being loaded with iron oxyhydroxide, and improves the removal performance of glyphosate.

Description

Technical Field

[0001] The present invention belongs to the field of water treatment adsorption composite materials, and particularly relates to a preparation method of a MIL-101(Fe) resin composite adsorbent, the obtained adsorbent and its application. Background Art

[0002] Phosphorus is one of the essential nutrients for plant growth. However, excessive phosphorus input in freshwater ecosystems can lead to eutrophication. Currently, research mainly focuses on inorganic phosphorus, with less attention paid to organic phosphorus. Glyphosate, as a non-selective broad-spectrum herbicide, seriously pollutes rivers, lakes, surface water, and groundwater due to its stability, high toxicity, and durability. Its harmful effects on plants, animals, and human health have been discovered. The US Environmental Protection Agency has set the maximum concentration of glyphosate in water at 0.28 mg / L. Therefore, it is necessary to develop efficient methods to remove glyphosate from water.

[0003] Metal-organic frameworks (MOFs), as a unique organic-inorganic hybrid material, have a higher specific surface area and porosity than metal oxides. However, most MOF materials are nano-porous / microporous materials, which greatly limit the mass transfer process. In addition, due to the small particle size, recycling and reuse will face great difficulties and potential environmental toxicity. So far, many measures have been taken to overcome this technical bottleneck. A better alternative is to immobilize metal nanoparticles in larger traditional adsorbents, such as ion exchange resins, which not only helps to disperse the metal nanoparticles,

[0004] but also ensures that the loaded nanoparticles have a specific affinity for the target pollutants. As one of the preparation methods of iron-based porous organic polymers, the confined space solvothermal synthesis of nanocomposites is more stringent than the alkali precipitation method. Synthesizing crystalline materials at high temperature and high pressure in a suitable solvent is a feasible method. It can regulate the growth kinetics and prevent nanoparticle aggregation. Chinese Patent with application number CN202210642295.7 discloses a preparation method, application, and recycling method of a metal-organic framework material MIL-101(Fe). The MIL-101(Fe) is prepared by a thermal solvent method, and the prepared MIL-101(Fe) is used as an adsorbent to adsorb tetracycline in water. After adsorbing tetracycline, the final iron-carbon composite wave-absorbing material can be obtained by one-step pyrolysis. However, the MIL-101(Fe) prepared by this method is difficult to regenerate and recycle as an adsorbent.

[0005] If only the solvothermal method is used to load iron active substances onto the resin, the iron loading rate will reach a certain saturation value, and the crystal structure of the material is not obvious. Generally speaking, the existing iron loading rate needs to be further improved to enhance the adsorption effect on phosphine in water treatment. Moreover, the existing adsorption materials are difficult to recycle and regenerate and have environmental toxicity. Summary of the Invention

[0006] Object of the Invention: In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a preparation method of an MIL-101(Fe) resin composite adsorbent with a relatively high iron loading amount. Another object of the present invention is to provide an MIL-101(Fe) resin composite adsorbent with stable regenerability and anti-interference ability. Still another object of the present invention is the application of an MIL-101(Fe) resin composite adsorbent in adsorbing glyphosate in water at a concentration of 1 to 200 mg / L.

[0007] Technical Solution: The preparation method of an MIL-101(Fe) resin composite adsorbent according to the present invention includes the following steps:

[0008] (1) Pretreat the anion exchange resin;

[0009] (2) Dissolve ferric chloride hexahydrate in hydrochloric acid, then add the anion exchange resin obtained in step (1), stir, filter, and dry to obtain the iron-loaded resin;

[0010] (3) Add the iron-loaded resin to a sodium hydroxide solution, stir, wash until neutral, and then dry;

[0011] (4) Add the product obtained in step (3) to a terephthalic acid solution dissolved in N,N-dimethylformamide, stir, and react at 80 to 120 °C for 16 to 24 h. After cooling, wash and dry to obtain the MIL-101(Fe) resin composite adsorbent.

[0012] Further, in step (1), the anion exchange resin is D201 resin or IRA900 resin. The pretreatment is to soak the anion exchange resin in an analytical grade acetone solution for purification for 12 to 24 h.

[0013] Further, in step (2), the mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:1.4 to 12.2.

[0014] Further, in step (3), the mass percentage of the sodium hydroxide solution is 10 to 20 wt.%.

[0015] Further, in step (4), the mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:1.2 to 6.2. The drying temperature is 50 to 80 °C, and the time is 8 to 12 h.

[0016] Further, the washing is carried out with one or more of deionized water, N,N-dimethylformamide, and ethanol.

[0017] The MIL-101(Fe) resin composite adsorbent obtained by the above preparation method is an anion exchange resin loaded with MIL-101(Fe), and the iron content loaded in the composite adsorbent accounts for 5.14-8.89% of the total mass of the composite adsorbent.

[0018] Application of the above MIL-101(Fe) resin composite adsorbent in adsorbing glyphosate in water at a concentration of 1-200 mg / L.

[0019] Preparation principle: The in-situ transformation method is adopted. First, iron hydroxide is loaded by the precipitation method, and then it is in-situ transformed into MIL-101(Fe) with the oxide as the seed. The obtained composite adsorbent has a higher loading amount; and through solvothermal treatment, MOF can be uniformly dispersed in the pores of the resin, increasing the active sites for interacting with glyphosate and the specific surface area, thereby improving the adsorption performance. The use of organic solvent regeneration solves the problem of the structure of MOF being damaged under alkaline conditions, thus realizing stable regeneration.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0021] 1. The obtained MIL-101(Fe) resin composite adsorbent has an increased specific surface area on the basis of loading iron hydroxide, and improves the removal performance of glyphosate;

[0022] 2. The prepared MIL-101(Fe)-loaded resin composite adsorbent has good affinity for low-concentration glyphosate, has strong anti-interference performance under a certain ion concentration, and can achieve stable regeneration;

[0023] 3. The MIL-101(Fe) formed by in-situ transformation can be better dispersed in the pores of the ion exchange resin to avoid agglomeration, improving the utilization rate of the metal, and also solving the problems of small particle size of MOF, difficult recovery and regeneration, and potential environmental toxicity;

[0024] 4. The matrix material and metal salt are cheap and easily available, with a wide range of sources, and have high economic benefits for large-scale production;

[0025] 5. The obtained MIL-101(Fe)-loaded resin composite adsorbent has a low leaching rate and good stability in a wide pH range, avoiding the problem of secondary pollution. Description of the drawings

[0026] Figure 1 It is the XRD pattern of Oxide(Fe)@201 resin in Example 1 of the present invention;

[0027] Figure 2 It is the XRD pattern of the composite adsorbent obtained in Example 1 of the present invention;

[0028] Figure 3 It is the XRD pattern of the composite adsorbent obtained in Example 2 of the present invention;

[0029] Figure 4 It is the XRD pattern of the composite adsorbent obtained in Example 3 of the present invention;

[0030] Figure 5 It is the XRD pattern of the composite adsorbent obtained in Example 4 of the present invention;

[0031] Figure 6 It is the XRD pattern of the composite adsorbent obtained in Example 5 of the present invention;

[0032] Figure 7 It is the XRD pattern of the composite adsorbent obtained in Example 6 of the present invention;

[0033] Figure 8 It is the adsorption performance graph of the composite adsorbent obtained in Example 3 of the present invention for glyphosate solutions with different pH values;

[0034] Figure 9 It is the anti-interference performance graph of the composite adsorbent obtained in Example 3 of the present invention for glyphosate solutions;

[0035] Figure 10 It is the cyclic regeneration graph of the composite adsorbent obtained in Example 3 of the present invention;

[0036] Figure 11 It is the XRD pattern of the MIL-101(Fe)-201 resin obtained in Comparative Example 2;

[0037] Figure 12 It is the comparison graph of the adsorption performances of different composite adsorbents for glyphosate solutions with different pH values. Detailed implementation manners

[0038] In the following examples, the D201 resin is produced by Ningbo Zhengguang Resin Co., Ltd., and the IRA900 resin is produced by Rohm and Haas Company of the United States.

[0039] Example 1

[0040] A preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps:

[0041] (1) Pretreat the anion exchange resin D201 resin by soaking it in an acetone solution for purification for 12 - 24 h.

[0042] (2) Prepare 50 mL of an iron salt solution (0.3 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), then add the anion exchange resin obtained in step (1). The mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:4.1. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the metal salt solution and place it in a vacuum drying oven at 60 °C for 12 h to obtain the iron-loaded resin.

[0043] (3) Add the iron-loaded resin to a sodium hydroxide solution with a mass percentage of 15 wt.%. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the concentrated alkali solution, wash it with deionized water until neutral, then rinse it once with ethanol, place it in a vacuum drying oven at 60 °C for 12 h and take it out to obtain the iron oxide resin, denoted as Oxide(Fe)@201, as Figure 1 , whose XRD pattern shows that Oxide(Fe)@201 is successfully synthesized, and there are diffraction peaks at 2θ angles of 35.34 and 62.36, and the crystal structure of iron oxide is obvious.

[0044] (4) Prepare 30 mL of a terephthalic acid solution (0.5 M terephthalic acid dissolved in N,N-dimethylformamide), add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide. The mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:5. Stir magnetically at 25 °C with a magnetic stirrer speed of 80 r / min, mix well for 30 min, transfer it to a 50 mL polytetrafluoroethylene reaction kettle, place it in a drying oven at 80 °C for 20 h. After the reaction kettle cools down, take it out, wash it 4 times with N,N-dimethylformamide solvent and then rinse it once with ethanol, place it in a drying oven at 60 °C for 12 h to obtain the MIL-101(Fe) resin composite adsorbent, denoted as MIL-101(Fe)@201-1.

[0045] As Figure 2 , the 2θ angles of the X-ray diffraction pattern of the MIL-101(Fe) resin composite adsorbent prepared in this example have diffraction peaks at 9.02, 12.62, and 18.18, and the crystal structure is obvious.

[0046] Example 2

[0047] A preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps:

[0048] (1) Pretreat the anion exchange resin D201 resin by soaking it in an acetone solution for 12 - 24 h for purification.

[0049] (2) Prepare 50 mL of an iron salt solution (0.3 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), and then add the anion exchange resin obtained in step (1). The mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:4.1. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the metal salt solution and place it in a vacuum drying oven at 60 °C for 12 h to obtain the iron-loaded resin.

[0050] (3) Add the iron-loaded resin to a sodium hydroxide solution with a mass percentage of 15 wt.%. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the concentrated alkali solution, wash it with deionized water until neutral, then rinse it once with ethanol, and place it in a vacuum drying oven at 60 °C for 12 h and then take it out to obtain the iron oxide resin, denoted as Oxide(Fe)@201.

[0051] (4) Prepare 30 mL of a terephthalic acid solution (0.5 M terephthalic acid dissolved in N,N-dimethylformamide), and add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide. The mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:5. Stir magnetically at 25 °C with a magnetic stirrer speed of 80 r / min, mix well for 30 min, transfer it to a 50 mL polytetrafluoroethylene reaction kettle, and place it in a drying oven at 90 °C for 20 h. After the reaction kettle cools down, take it out, wash it 4 times with N,N-dimethylformamide solvent and then rinse it once with ethanol, and place it in a drying oven at 60 °C for 12 h to obtain the MIL-101(Fe) resin composite adsorbent, denoted as MIL-101(Fe)@201-2.

[0052] As Figure 3 , the X-ray diffraction pattern of the MIL-101(Fe) resin composite adsorbent prepared in this example has diffraction peaks at 2θ angles of 9.02, 12.62, and 18.18, and the crystal structure is obvious.

[0053] Example 3

[0054] A preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps:

[0055] (1) Pretreat the anion exchange resin D201 resin by soaking it in an acetone solution for 12 - 24 h for purification.

[0056] (2) Prepare 50 mL of iron salt solution (0.3 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), and then add the anion exchange resin obtained in step (1). The mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:4.1. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the metal salt solution and place it in a vacuum drying oven at 60 °C for drying for 12 h to obtain iron-loaded resin.

[0057] (3) Add the iron-loaded resin to a sodium hydroxide solution with a mass percentage of 15 wt.%. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the concentrated alkali solution, wash it with deionized water until neutral, then rinse it once with ethanol, place it in a vacuum drying oven at 60 °C for drying for 12 h, and then take it out to obtain iron oxide resin, denoted as Oxide(Fe)@201.

[0058] (4) Prepare 30 mL of terephthalic acid solution (0.5 M terephthalic acid dissolved in N,N-dimethylformamide). Add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide. The mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:5. Stir magnetically at 25 °C with a magnetic stirrer speed of 80 r / min, mix well for 30 min, transfer it to a 50 mL polytetrafluoroethylene reaction kettle, place it in a drying oven at 100 °C for reacting for 20 h. After the reaction kettle cools down, take it out, wash it 4 times with N,N-dimethylformamide solvent and then rinse it once with ethanol, place it in a drying oven at 60 °C for drying for 12 h to obtain the MIL-101(Fe) resin composite adsorbent, denoted as MIL-101(Fe)@201-3.

[0059] As Figure 4 , for the MIL-101(Fe) resin composite adsorbent prepared in this example, the 2θ angles of the X-ray diffraction pattern have diffraction peaks at 9.02, 12.62, and 18.18, and the crystal structure is obvious.

[0060] Example 4

[0061] A preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps:

[0062] (1) Pretreat the anion exchange resin D201 resin by soaking it in an acetone solution for purification for 12 - 24 h.

[0063] (2) Prepare 50 mL of an iron salt solution (0.3 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), and then add the anion exchange resin obtained in step (1). The mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:4.1. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the metal salt solution and place it in a vacuum drying oven at 60 °C for drying for 12 h to obtain iron-loaded resin.

[0064] (3) Add the iron-loaded resin to a sodium hydroxide solution with a mass percentage of 15 wt.%. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the concentrated alkali solution, wash it with deionized water until neutral, then rinse it once with ethanol, and place it in a vacuum drying oven at 60 °C for drying for 12 h and then take it out to obtain iron oxide resin, denoted as Oxide(Fe)@201.

[0065] (4) Prepare 30 mL of a terephthalic acid solution (0.125 M terephthalic acid dissolved in N,N-dimethylformamide), and add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide. The mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:5. Stir magnetically at 25 °C with a magnetic stirrer speed of 80 r / min, mix well for 30 min, transfer it to a 50 mL polytetrafluoroethylene reaction kettle, and place it in a drying oven at 80 °C for reacting for 20 h. After the reaction kettle cools down, take it out, wash it 4 times with N,N-dimethylformamide solvent and then rinse it once with ethanol, and place it in a drying oven at 60 °C for drying for 12 h to obtain the MIL-101(Fe) resin composite adsorbent, denoted as MIL-101(Fe)@201-4.

[0066] As Figure 5 , the X-ray diffraction pattern of the MIL-101(Fe) resin composite adsorbent prepared in this example has diffraction peaks at 2θ angles of 9.02, 12.62, and 18.18, and the crystal structure is obvious.

[0067] Example 5

[0068] A preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps:

[0069] (1) Pretreat the anion exchange resin D201 resin by soaking it in an acetone solution for purification for 12 - 24 h.

[0070] (2) Prepare 50 mL of an iron salt solution (0.3 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), and then add the anion exchange resin obtained in step (1). The mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:4.1. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the metal salt solution and place it in a vacuum drying oven at 60 °C for drying for 12 h to obtain iron-loaded resin.

[0071] (3) Add the iron-loaded resin to a sodium hydroxide solution with a mass percentage of 15 wt.%. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the concentrated alkali solution, wash it with deionized water until neutral, and then rinse it once with ethanol. Place it in a vacuum drying oven at 60 °C for drying for 12 h and then take it out to obtain iron oxide resin, denoted as Oxide(Fe)@201.

[0072] (4) Prepare 30 mL of a terephthalic acid solution (0.375 M terephthalic acid dissolved in N,N-dimethylformamide), and add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide. The mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:5. Stir magnetically at 25 °C with a magnetic stirrer speed of 80 r / min, mix well for 30 min, transfer it to a 50 mL polytetrafluoroethylene reaction kettle, and place it in a drying oven at 80 °C for reacting for 20 h. After the reaction kettle cools down, take it out, wash it 4 times with N,N-dimethylformamide solvent and then rinse it once with ethanol. Place it in a drying oven at 60 °C for drying for 12 h to obtain the MIL-101(Fe) resin composite adsorbent, denoted as MIL-101(Fe)@201-5.

[0073] As Figure 6 , the X-ray diffraction pattern of the MIL-101(Fe) resin composite adsorbent prepared in this example has diffraction peaks at 2θ angles of 9.02, 12.62, and 18.18, and the crystal structure is obvious.

[0074] Example 6

[0075] A preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps:

[0076] (1) Pretreat the anion exchange resin IRA900 resin by soaking it in an acetone solution for purification for 12 - 24 h.

[0077] (2) Prepare 50 mL of iron salt solution (0.2 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), then add the anion exchange resin obtained in step (1). The mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:1.4. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the metal salt solution and place it in a vacuum drying oven at 60 °C for drying for 12 h to obtain iron-loaded resin.

[0078] (3) Add the iron-loaded resin to a sodium hydroxide solution with a mass percentage of 10 wt.%. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the concentrated alkali solution, wash it with deionized water until it is neutral, then rinse it once with ethanol, place it in a vacuum drying oven at 60 °C for drying for 12 h, and then take it out to obtain iron oxide resin, denoted as Oxide(Fe)@201.

[0079] (4) Prepare 30 mL of terephthalic acid solution (0.25 M terephthalic acid dissolved in N,N-dimethylformamide), add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide. The mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:1.2. Stir magnetically at 25 °C with a magnetic stirrer speed of 80 r / min, mix well for 30 min, transfer it to a 50 mL polytetrafluoroethylene reaction kettle, place it in a drying oven at 120 °C for reacting for 16 h. After the reaction kettle cools down, take it out, wash it 4 times with N,N-dimethylformamide solvent and then rinse it once with ethanol, and place it in a drying oven at 50 °C for drying for 10 h to obtain the MIL-101(Fe) resin composite adsorbent, denoted as MIL-101(Fe)@301-1.

[0080] Example 7

[0081] A preparation method of a MIL-101(Fe) resin composite adsorbent, comprising the following steps:

[0082] (1) Pretreat the anion exchange resin IRA900 resin by soaking it in an acetone solution for purification for 12 - 24 h.

[0083] (2) Prepare 50 mL of iron salt solution (0.25 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), then add the anion exchange resin obtained in step (1). The mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1:12.2. Stir magnetically at 25 °C with a magnetic stirrer speed of 150 r / min. After reacting for 12 h, filter out the metal salt solution and place it in a vacuum drying oven at 60 °C for drying for 12 h to obtain iron-loaded resin.

[0084] (3) Add the iron-loaded resin to a sodium hydroxide solution with a mass percentage of 20 wt.%, stir magnetically at 25 °C, with the magnetic stirrer speed at 150 r / min. After reacting for 12 h, filter out the concentrated alkali solution, wash it with deionized water until neutral, then rinse it once with ethanol, and place it in a vacuum drying oven at 60 °C for 12 h. After taking it out, the iron oxide resin is obtained, denoted as Oxide(Fe)@201.

[0085] (4) Prepare 30 mL of terephthalic acid solution (0.375 M terephthalic acid dissolved in N,N-dimethylformamide), add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide. The mass ratio of the product obtained in step (3) to the ligand terephthalic acid is 1:6.2. Stir magnetically at 25 °C, with the magnetic stirrer speed at 80 r / min, mix well for 30 min, transfer it to a 50 mL polytetrafluoroethylene reaction kettle, and place it in a drying oven at 110 °C for 24 h. After the reaction kettle cools down, take it out, wash it 4 times with N,N-dimethylformamide solvent and then rinse it once with ethanol, and place it in a drying oven at 80 °C for 8 h to obtain the MIL-101(Fe) resin composite adsorbent, denoted as MIL-101(Fe)@301-2.

[0086] Comparative Example 1

[0087] In order to demonstrate the performance difference between Oxide(Fe)@201 resin and MIL-101(Fe)@201 at a similar loading rate, an adsorption performance test was carried out. An Oxide(Fe)@201-1 resin was prepared, and the preparation method specifically includes the following steps:

[0088] (1) Prepare 50 mL of iron salt solution (0.2 M ferric chloride hexahydrate dissolved in 5 M dilute hydrochloric acid), add ion exchange resin (the mass ratio of ferric chloride hexahydrate to resin is 2.7:1), stir magnetically at 25 °C (magnetic stirrer speed at 150 r / min) for 12 h, and then filter out the metal salt solution.

[0089] (2) Place the resin filtered out in step (1) in a vacuum drying oven at 60 °C for 12 h, and then take it out for standby.

[0090] (3) Add the resin dried in step (2) to a concentrated alkali solution with a mass fraction of 10 wt.%, stir magnetically at 25 °C (magnetic stirrer speed at 150 r / min) for 12 h, filter out the concentrated alkali solution, wash it with deionized water until neutral, then rinse it once with ethanol, and place it in a vacuum drying oven at 60 °C for 12 h. After taking it out, the Oxide(Fe)@201-1 resin is obtained.

[0091] Weigh 50 mg of the prepared Oxide(Fe)@201-1 and 50 mg of the MIL-101(Fe)@201-3 resin prepared in Example 3 into a 150 mL conical flask, add them to 100 mL of glyphosate solutions with concentrations of 2 mg / L, 20 mg / L, and 100 mg / L, place them on a shaker at a temperature of 25 °C and a rotation speed of 150 rpm for an adsorption experiment. After adsorption for 12 h, take samples to measure the adsorption capacity of the two materials.

[0092] The results are as Figure 7 shown. At the same loading rate, when the iron contents of Oxide(Fe)@201-1 and MIL-101(Fe)@201-3 are 8.87% and 8.91% respectively, at different initial glyphosate concentrations, the adsorption capacity of MIL-101(Fe)@201-3 is higher than that of the Oxide(Fe)@201-1 resin.

[0093] Test 1

[0094] To explore the relationship between the adsorption of glyphosate at low concentrations (1 - 200 mg / L) by the MIL-101(Fe)@201-3 resin prepared in Example 3 and the solution pH value, the following operations are carried out:

[0095] Prepare 100 mL of 2 mg / L glyphosate solutions with pH values of 2, 4, 6, 7, 8, 10, and 12 in advance, add 50 mg of the MIL-101(Fe)@201-3 resin, place them on a shaker at a temperature of 25 °C and a rotation speed of 150 rpm for an adsorption experiment. After adsorption for 12 h, take samples to measure the adsorption capacity of the composite material.

[0096] The results are as Figure 8 shown. In the glyphosate solution with pH = 6 - 8, the MIL-101(Fe)@201-3 resin has good removal effects on glyphosate, and the removal rate reaches over 80%. When the pH of the glyphosate solution is 6, the removal effect is the best, up to 94.91%.

[0097] Test 2

[0098] To explore the anti-interference performance of the MIL-101(Fe)@201-3 resin prepared in Example 3 for glyphosate at low concentrations (1 - 200 mg / L), an adsorption performance test is carried out, including the following steps: Prepare 100 mL of 2 mg / L containing SO4 2- , Cl - , HCO3 - and NO3 -A glyphosate solution with a mass ratio of 5:10:20:1 was added with 50 mg of the adsorbent from Example 3 and placed in a shaker at a temperature of 25 °C and a rotation speed of 150 rpm for an adsorption experiment. After 12 h of adsorption, a sample was taken to measure the adsorption capacity of the composite material.

[0099] The results are as Figure 9 shown. In the range of interference ion concentration from 2 to 40 mg / L, the resin has high anti-interference performance.

[0100] Test 3

[0101] To explore the reuse effect of the MIL-101(Fe)@201-3 resin prepared in Example 3, performance tests were carried out, including the following steps:

[0102] First, an adsorption experiment was carried out. The adsorbent prepared in Example 3 was added to 100 mL of a glyphosate solution with a concentration of 2 mg / L and placed in a shaker at a temperature of 25 °C and a rotation speed of 150 rpm for an adsorption experiment. After 12 h of adsorption, a desorption experiment was carried out. The desorption solution used ethanol, and the desorption time was 6 h. Finally, it was washed with deionized water and reused. The results are as Figure 10 shown. After 5 cycles, the removal rate still reached 84%, indicating that good stability was maintained after multiple regenerations.

[0103] Comparative Example 2

[0104] A preparation method of MIL-101(Fe)-201 resin using the hot solvent method includes the following steps:

[0105] Using ferric chloride hexahydrate, D201 resin, terephthalic acid, and N,N-dimethylformamide as raw materials, an ultrasonic dissolution was used to form a homogeneous solution, which was then transferred to a glass bottle and then transferred to an oven for reaction at 110 °C for 20 h. After the reaction was completed, centrifugation, washing, and drying were carried out to obtain the MIL-101(Fe)-201 resin material. As Figure 11 shown, its XRD pattern shows that the crystal structure of the material is not obvious.

[0106] Weigh 50 mg of MIL-101(Fe)-201 prepared in this comparative example and the MIL-101(Fe)@201-3 resin prepared in Example 3 into 150 mL conical flasks, and add them to 100 mL of glyphosate solutions with concentrations of 2 mg / L, 20 mg / L, and 100 mg / L. Place them in a shaker at a temperature of 25 °C and a rotation speed of 150 rpm for an adsorption experiment. After 12 h of adsorption, a sample was taken to measure the adsorption capacity of the two materials.

[0107] The results show that at the same loading rate, the iron contents of MIL-101(Fe)-201 and MIL-101(Fe)@201-3 are 1.64% and 8.91% respectively.

[0108] Pre-prepare 100 mL of 2 mg / L glyphosate solutions with pH values of 2, 4, 6, 7, 8, 10, and 12 at 2 mg / L respectively. Add 50 mg of MIL-101(Fe)@201-3 resin and MIL-101(Fe)-201 resin respectively, and place them in a shaker at a temperature of 25 °C and a rotation speed of 150 rpm for the adsorption experiment. After 12 h of adsorption, sample and measure the adsorption capacity of the composite material.

[0109] The results are as Figure 12 shown. At different pH values, the adsorption capacity of MIL-101(Fe)@201-3 resin is always higher than that of MIL-101(Fe)-201 resin.

Claims

1. A preparation method of a MIL-101(Fe) resin composite adsorbent, characterized in that, It includes the following steps: (1) Pretreat the anion exchange resin; (2) Dissolve ferric chloride hexahydrate in hydrochloric acid, then add the anion exchange resin obtained in step (1), stir, filter and dry to obtain the iron-loaded resin; (3) Add the iron-loaded resin to sodium hydroxide solution, stir, wash until neutral and then dry; (4) Add the product obtained in step (3) to the terephthalic acid solution dissolved in N,N-dimethylformamide, stir, react at 80-120 °C for 16-24 h, cool, wash and dry to obtain the MIL-101(Fe) resin composite adsorbent; In step (1), the anion exchange resin is D201 resin or IRA900 resin.

2. The preparation method of a MIL-101(Fe) resin composite adsorbent according to claim 1, characterized in that: In step (1), the pretreatment is to soak the anion exchange resin in acetone solution for purification for 12-24 h.

3. The preparation method of a MIL-101(Fe) resin composite adsorbent according to claim 1, characterized in that: In step (2), the mass ratio of the anion exchange resin to ferric chloride hexahydrate is 1: 1.4-12.

2.

4. The preparation method of a MIL-101(Fe) resin composite adsorbent according to claim 1, characterized in that: In step (3), the mass percentage of the sodium hydroxide solution is 10-20 wt.%.

5. The preparation method of a MIL-101(Fe) resin composite adsorbent according to claim 1, characterized in that: In step (4), the mass ratio of the product obtained in step (3) to terephthalic acid is 1: 1.2-6.

2.

6. The preparation method of a MIL-101(Fe) resin composite adsorbent according to claim 1, characterized in that: In step (4), the drying temperature is 50-80 °C and the time is 8-12 h.

7. The preparation method of a MIL-101(Fe) resin composite adsorbent according to claim 1, characterized in that: The washing is carried out by one or more of deionized water, N,N-dimethylformamide and ethanol.

8. The MIL-101(Fe) resin composite adsorbent obtained by the preparation method according to any one of claims 1 to 7, characterized in that: For the anion exchange resin loaded with MIL-101(Fe), the iron content loaded in the composite adsorbent accounts for 5.14-8.89% of the total mass of the composite adsorbent.

9. Application of the MIL-101(Fe) resin composite adsorbent according to claim 8 in adsorbing glyphosate in water at 1-200 mg / L.

Images