Preparation and application of an ionic liquid modified metal organic framework material derived carbon material

Abstract

The present invention discloses a method for preparing a carbon material derived from a metal organic framework material modified by an ionic liquid, wherein the Fe-containing carbon material is produced after the heavy metal slag is treated with acid. 2+ The waste liquid is directly used as a raw material to coordinate with organic ligands to synthesize metal-organic framework materials. The ultra-large pores exposed by the magnetic carbon material derived by high-temperature carbonization provide abundant binding sites for loading ionic liquids, which is conducive to the modification of ionic liquids. The introduction of ionic liquids enriches the functional group properties of porous carbon materials and introduces ionic interactions, which enhances the interaction between porous carbon materials and target pollutants. Therefore, porous carbon materials derived from metal-organic framework materials modified with ionic liquids can be used as excellent magnetic solid-phase extraction adsorbents for the efficient extraction of residual pesticides in the environment.

Description

Technical Field

[0001] The present invention relates to a metal organic framework material, in particular to the preparation and application of a metal organic framework material-derived carbon material modified by an ionic liquid, and belongs to the field of composite material preparation and complex system sample pretreatment. Background Art

[0002] The rapid development of the country's social economy has put forward higher requirements for environmental governance. The pollution-free treatment of industrial solid waste and the comprehensive utilization of resources are one of the major issues that need to be solved urgently. Recovering the residual trace heavy metals by treating heavy metal slag not only saves resources but also effectively avoids the problem of heavy metal pollution. The technical method for efficient dissociation of nickel metallurgical waste slag (authorization announcement number CN115786719B) improves the efficiency of heavy metal resource recovery in slag, but the generated Fe 2+ Fe-based metal-organic framework materials (MOFs) are a type of porous material formed by Fe as a metal node. 2+ As a metal node, Fe-based MOF is synthesized by coordination with organic ligands at room temperature and water system, and then Fe3O4@C magnetic carbon material is derived by high temperature carbonization. 2+ The ultra-large pores exposed in the carbon materials, derived from the complexity of the wastewater, retain their original framework structure. The Fe₃O₄ generated through carbonization has excellent magnetic responsiveness, enabling rapid solid-liquid separation under the action of an external magnet. This allows for adsorbents in magnetic solid phase extraction (MSPE). The large pores provide abundant loading sites for ionic liquids, facilitating their modification. Ionic liquid modification increases the functional group properties of the porous carbon materials and enhances the interaction between them and the target pollutants. Therefore, porous carbon materials derived from ionic liquid-modified metal-organic frameworks can be used as excellent magnetic solid phase extraction adsorbents for the efficient extraction of pyrethroid insecticides in the environment. Summary of the Invention

[0003] The present invention aims to provide a method for preparing a carbon material derived from a metal organic framework material modified by an ionic liquid, thereby providing a green treatment method for Fe-containing waste liquid generated after recovering trace heavy metals from slag waste liquid.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The preparation of an ionic liquid modified metal organic framework material derived carbon material comprises the following steps:

[0006] (1) Synthesis of Fe-based MOF at room temperature: 1,3,5-trimethylbenzene tricarboxylic acid was dissolved in deionized water and stirred to obtain solution 1. The pH of the solution was adjusted to 13-14 using NaOH. 2+ The waste liquid was slowly added dropwise to solution 1, magnetically stirred at room temperature for 6 to 48 hours, centrifuged, washed with ethanol and deionized water, and vacuum dried at 70 to 80° C. to obtain MIL-100(Fe).

[0007] Contains Fe 2+ Source of waste liquid: The nickel metallurgical waste residue obtained after the flash furnace smelting of the copper-nickel sulfide ore of Jinchuan Company is mixed with sulfuric acid and reacted under high temperature and high pressure conditions to convert the metals such as iron, cobalt, nickel and copper into ions and separate them from the precipitated silica. The obtained solution containing the metal ions such as iron, cobalt, nickel and copper is then passed through hydrogen sulfide gas and filtered to obtain black nickel-cobalt-copper sulfide precipitate and a solution mainly containing Fe 2+ Wastewater containing Fe 2+ The pH of the wastewater is 2.5~3.0, and the Fe 2+ The content is 80~100g / L.

[0008] The concentration of the solution 1 is 0.2mM~0.4mM, and each 10mL contains Fe 2+ The volume of solution 1 required for waste liquid is 12~14mL.

[0009] (2) Preparation of Fe3O4@C: MIL-100(Fe) was placed in a muffle furnace and heated to 500-600°C at a heating rate of 5-10°C / min in an air atmosphere for calcination for 1.5-2.5 h. The mixture was naturally cooled to room temperature, washed alternately with ethanol and deionized water, and dried in a vacuum at 70-80°C to obtain Fe3O4@C.

[0010] (3) Preparation of Fe3O4@C / [BMIM]PF6: 1-Butyl-3-methylimidazolium hexafluorophosphate was first dissolved in anhydrous ethanol, and then Fe3O4@C was added and ultrasonically mixed until the ethanol was completely evaporated. Finally, the mixture was vacuum dried at 65-75°C for 4-6 h. The collected product was Fe3O4@C / [BMIM]PF6; the mass ratio of 1-butyl-3-methylimidazolium hexafluorophosphate to Fe3O4@C was 1:10-3:10.

[0011] The present invention adopts the impregnation method to modify 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid in the Fe3O4@C cavity to prepare the ionic liquid modified metal oxide carbon material. Among them, Fe-based MOF is the Fe in the Fe-containing waste liquid generated after heavy metal waste is recovered by efficient dissociation technology. 2+It is a metal node and is synthesized by coordination with organic ligands at room temperature and in an aqueous system. Due to the complexity of the components in Fe-containing wastewater, the Fe3O4@C carbon material derived from Fe-based MOF in an air atmosphere exposes ultra-large pores and retains the original framework structure. At the same time, the Fe3O4 generated by carbonization treatment has excellent magnetic responsiveness and can quickly achieve solid-liquid separation under the action of an external magnet. Therefore, it can be used as an adsorbent for magnetic solid phase extraction (MSPE). In addition, the generation of large pores provides abundant loading sites for ionic liquids, which is conducive to the modification of ionic liquids. The introduction of ionic liquids enriches the functional group properties of porous carbon materials and enhances the interaction between porous carbon materials and target pollutants.

[0012] Therefore, based on the advantages of the composite material such as a larger pore structure, a higher specific surface area and excellent ferromagnetism, another object of the present invention is to disclose the application of the metal-organic framework material-derived carbon material as an adsorbent in the magnetic solid-phase extraction of pyrethroid insecticides.

[0013] In summary, the present invention has the following advantages:

[0014] 1. The present invention uses heavy metal waste slag to recover heavy metals through efficient dissociation technology. 2+ The waste liquid is used to synthesize MOFs as metal nodes, which effectively provides a simple and green treatment method for Fe-containing waste liquid; the Fe-containing waste liquid is turned into treasure and recycled for the adsorption of residual pesticides in the environment, protecting the environment while reducing the consumption generated by treating the waste liquid.

[0015] 2. Fe contained in Fe-containing wastewater 2+ Using metal nodes, an Fe-based MOF was synthesized by coordination with trimesic acid at room temperature in water. The Fe-based MOF, derived in air, exposed ultra-large pores in the Fe₃O₄@C carbon material. The Fe₃O₄ generated by carbonization exhibited excellent magnetic responsiveness. Ionic liquids were loaded into the pores of the carbon material, successfully preparing an ionic liquid-modified metal oxide carbon material, Fe₃O₄@C / [BMIM]PF₆.

[0016] 3. Fe3O4@C / [BMIM]PF6 retains the fundamental characteristics of MOFs. Derived from Fe3O4@C by carbonization of Fe-based MOFs, the complex composition of Fe-containing wastewater exposes large pores that provide loading sites for ionic liquids. Ionic liquid modification enhances the hydrophobicity of the material while increasing the functional group properties of the porous carbon material, strengthening the interaction between the porous carbon material and the target pollutant. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a scanning electron microscope image of the material MIL-100 (Fe) in Example 1 of the present invention.

[0018] Figure 2 This is a transmission electron microscope image of the material MIL-100 (Fe) in Example 1 of the present invention.

[0019] Figure 3 This is a transmission electron microscope image of the material Fe3O4@C in Example 1 of the present invention.

[0020] Figure 4 This is a transmission electron microscope image of the material Fe3O4@C / [BMIM]PF6 in Example 1 of the present invention.

[0021] Figure 5 This is a locally enlarged transmission electron microscope image of the material Fe3O4@C / [BMIM]PF6 in Example 1 of the present invention.

[0022] Figure 6 This is the magnetic adsorption diagram of the material Fe3O4@C / [BMIM]PF6 in Example 1 of the present invention.

[0023] Figure 7 This is the liquid chromatography elution curve of the 2 mg / L mixed standard solution in Example 2 of the present invention.

[0024] Figure 8 This is the elution curve of the liquid chromatogram of the analytical solution after extraction in Example 2 of the present invention. DETAILED DESCRIPTION

[0025] In order to better understand the present invention, the present invention is described in detail through specific embodiments.

[0026] The instruments and reagents used in the present invention are as follows:

[0027] Agilent 1100 liquid chromatograph equipped with UV detector, Agilent, USA; C18 chromatographic column (Hypersil ODS2, 250 mm × 4.6 mm id, 5 μm).

[0028] Flucythrin, lambda-cyhalothrin, cypermethrin, fluvalinate, and 1,3,5-trimethylbenzene were obtained from Beijing Inokai Technology Co., Ltd., Beijing, China. NaOH (analytical grade) was obtained from Li-An Long Bo Hua (Tianjin) Pharmaceutical Chemical Co., Ltd., Tianjin, China. Methanol and acetonitrile (chromatographic grade) were obtained from Yuwang Chemical Co., Ltd., Shandong, China. Anhydrous ethanol (analytical grade) was obtained from Tianjin Damao Chemical Reagent Factory, Tianjin, China. Distilled water was obtained from a Milli-Q system.

[0029] Example 1. Preparation of ionic liquid modified carbon material derived from metal organic framework synthesized from slag wastewater

[0030] (1) Collect heavy metal waste residues and recover heavy metals through efficient dissociation technology to produce Fe-containing 2+ Wastewater containing Fe 2+ The aqueous phase of the wastewater was filtered through a 0.45µm filter to remove solid particles and stored in a 4°C refrigerator for later use. The pH value of the Fe-containing wastewater was 2.5-3.0. The Fe content in the wastewater was determined by ICP-OES. 2+ The content is 83.549g / L.

[0031] (2) Synthesis of Fe-based MOF at room temperature: 0.420 g (2 mM) 1,3,5-trimethylbenzene was accurately weighed and dissolved in 10 mL of deionized water and stirred to obtain solution 1. 0.4 g NaOH was added to adjust the pH of the solution to 14. The Fe-containing solution in (1) was stirred under magnetic stirring. 2+ 8.0 mL of the waste liquid was slowly added dropwise to solution 1. The mixed solution was magnetically stirred at room temperature for 24 h, and the solution changed from green to yellow-brown. The solution was centrifuged at 6500 rpm for 6 min, washed four times with ethanol and deionized water, and dried in vacuo at 75°C for 6 h to obtain MIL-100(Fe).

[0032] from Figure 1 From the scanning electron microscope image, it can be seen that the structure of MIL-100(Fe) is octahedral with obvious angular structure. The granular structure stacked next to the octahedron comes from the unknown components in the waste liquid. Figure 2 In the transmission electron microscope image of MIL-100(Fe), you can see the length of the material is about 700nm~800nm ​​and the width is about 500nm~600nm.

[0033] (3) Preparation of Fe3O4@C: The dried block of MIL-100(Fe) was ground into powder, 2.0 g was accurately weighed and placed in a muffle furnace. It was calcined at 500°C for 2 h at a heating rate of 10°C / min in an air atmosphere. After cooling naturally to room temperature, it was washed alternately with ethanol and deionized water for 4 times. Solid-liquid separation was achieved under the action of an external magnet. The solid was collected and dried in a vacuum at 70°C for 6 h to obtain Fe3O4@C.

[0034] from Figure 3 It can be seen that the material still maintains its original octahedral morphology after calcination. Figure 2 For example, the octahedral structure becomes granular inside, which indicates that carbonization changes the state of the core material and exposes large pores on the surface of the material.

[0035] (4) Preparation of Fe3O4@C / [BMIM]PF6: 1-Butyl-3-methylimidazolium hexafluorophosphate ionic liquid was modified in the Fe3O4@C cavity by impregnation. 30 mg of 1-Butyl-3-methylimidazolium hexafluorophosphate was dissolved in a small beaker containing 15 mL of anhydrous ethanol. 300 mg of Fe3O4@C was added and ultrasonicated for 5 min to mix evenly. Ultrasonication was continued for 1.5 h until the ethanol was completely evaporated. The beaker was placed in a vacuum drying oven at 65°C for 4 h and vacuum dried. The product Fe3O4@C / [BMIM]PF6 was collected.

[0036] from Figure 4 and Figure 5 It can be seen that after ionic liquid modification and long-term ultrasonic treatment, Fe3O4@C / [BMIM]PF6 has undergone significant changes compared to Fe3O4@C, but still maintains its original octahedral structure. Figure 6 It can be seen that the material has excellent magnetic responsiveness and can be quickly adsorbed by a magnet.

[0037] Example 2: Extraction of pyrethroid insecticides

[0038] (1) Preparation of standard solutions: Prepare standard stock solutions of flucythrin, lambda-cyhalothrin, cypermethrin, and fluvalinate at a concentration of 1.0 mg / mL using methanol as the solvent, and determine the retention time of each pyrethroid. Take 5 mL of each of the four target standard stock solutions and add them to a 25 mL volumetric flask. Add 5 mL of methanol to dilute the solution to a 0.2 mg / mL mixed standard solution. Mix the appropriate amount of the stock solution with distilled water to prepare a mixed standard solution at a concentration of 2 mg / L.

[0039] (2) Magnetic solid-phase extraction process: 1.0 mL of the mixed standard solution was diluted to 20 mL and mixed with 25 mg of the carbon material Fe3O4@C / [BMIM]PF6 for ultrasonic dispersion. The mixture was then shaken on an oscillator for 10 min to achieve adsorption saturation. The adsorbent was then separated using a magnet and the supernatant was removed. 1.0 mL of methanol was used as the eluent, and ultrasonic desorption was performed for 15 min. The adsorbent and eluent were then separated using a magnet. Finally, 20.0 µL of the desorption solution was injected into the HPLC-UV system for analysis.

[0040] Chromatographic analysis conditions were as follows: mobile phase: acetonitrile / water (88:12, v / v); flow rate: 1.0 mL / min; column temperature: 30°C; detection wavelength: 220 nm; injection volume: 20 µL. Each experiment was repeated three times to minimize systematic and operational errors.

[0041] Chromatogram of 2mg / L mixed standard solution is shown in Figure 7Under the above analytical conditions, the retention time of flucythrin was 7.32 min; the retention time of lambda-cyhalothrin was 9.06 min; the retention time of fenvalerate was 10.43 min; and the retention time of fluvalinate was 11.37 min.

[0042] The chromatogram of the HPLC analysis of the extracted solution is shown in Figure 8 Under the above analytical conditions, the retention time of flucythrin was 7.11 min; the retention time of lambda-cyhalothrin was 8.89 min; the retention time of fenvalerate was 10.16 min; and the retention time of fluvalinate was 11.17 min.

[0043] Table 1 Recovery calculation results

[0044]

[0045] Under these extraction conditions, the recovery rates for flucythrin, lambda-cyhalothrin, cypermethrin, fenvalerate, and fluvalinate were 96.73%, 96.13%, 96.07%, and 95.68%, respectively. Even without optimized extraction conditions, Fe₃O₄@C / [BMIM]PF₆ exhibited excellent extraction performance for pyrethroid insecticides, demonstrating the promising potential of this material for the extraction of pyrethroid insecticides.

Claims

1. An application of an ionic liquid modified metal organic framework material derived carbon material as an adsorbent in magnetic solid phase extraction of pyrethroid insecticides, characterized in that: The preparation method of the adsorbent, The following steps are involved: (1) Synthesis of Fe-based MOF at room temperature: 1,3,5-trimethylbenzene tricarboxylic acid was dissolved in deionized water and stirred to obtain solution 1. The pH of the solution was adjusted to 13-14 using NaOH. 2+ The waste liquid was slowly added dropwise to solution 1, magnetically stirred at room temperature for 6-48 h, centrifuged, washed with ethanol and deionized water, and dried under vacuum at 70-80 °C to obtain MIL-100(Fe); (2) Preparation of Fe3O4@C: MIL-100(Fe) was placed in a muffle furnace and heated to 500-600°C at a heating rate of 5-10°C / min in an air atmosphere for calcination for 1.5-2.5 h. The mixture was naturally cooled to room temperature, washed alternately with ethanol and deionized water, and dried in a vacuum at 70-80°C to obtain Fe3O4@C. (3) Preparation of Fe3O4@C / [BMIM]PF6: 1-Butyl-3-methylimidazolium hexafluorophosphate was first dissolved in anhydrous ethanol, and then Fe3O4@C was added and ultrasonically mixed. The ultrasonication was continued until the ethanol was completely evaporated. Finally, the mixture was vacuum dried at 65-75 °C for 4-6 h. The collected product was Fe3O4@C / [BMIM]PF6.

2. The use according to claim 1, characterized in that In step (1), the Fe-containing 2+ The pH of the wastewater is 2.5~3.0, and the Fe 2+ The content is 80~100g / L.

3. The use according to claim 1, characterized in that In step (1), each 10 mL contains Fe 2+ The volume of solution 1 required for waste liquid is 12-14 mL.

4. The use according to claim 1, wherein In step (3), the mass ratio of 1-butyl-3-methylimidazolium hexafluorophosphate to Fe3O4@C is 1:10 to 3:

10.

5. The use according to claim 1, characterized in that: The pyrethroid insecticide is at least one of flucythrin, lambda-cyhalothrin, cypermethrin and fluvalinate.

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