Nitrogen-rich organic molecule modified graphene oxide composite material, and preparation method and application thereof

Abstract

The application provides a nitrogen-rich organic molecule modified graphene oxide composite material and a preparation method and application thereof. The method comprises the following steps: adding graphene oxide into a polar organic solvent, ultrasonic dispersion and mixing to obtain a graphene oxide dispersion liquid; then adding 3,5-diamino-1,2,4-triazole into the graphene oxide dispersion liquid and mixing uniformly, and performing a nucleophilic reaction under weak acid heating condition; and finally washing the product with ethanol and pure water repeatedly, freezing and drying to obtain the nitrogen-rich organic molecule modified graphene oxide composite material. The composite material is used as an adsorbent, has a stable structure and high adsorption of heavy metal ions. The modification of the nitrogen-rich organic molecule makes the adsorbent have more abundant groups and adsorption sites, and can exhibit different adsorption capacities for inorganic metal cations through multiple adsorption mechanisms. The adsorption result shows that the adsorbent has excellent adsorption selectivity for low-concentration copper ions in an aqueous solution. After multiple adsorption-desorption experiments, the composite material still shows excellent repeated use performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to a nitrogen-rich organic molecule modified graphene oxide composite material and a preparation method and application thereof. BACKGROUND

[0002] Copper is a common heavy metal, which is widely used in life due to its low cost. With the continuous discharge of industrial wastewater, a large amount of heavy metal ions released by food chain bioaccumulation, its toxic and non-biodegradable physicochemical properties seriously affect the ecological environment. A variety of treatment processes such as chemical precipitation, reverse osmosis, coagulation, electrolysis, adsorption method and so on are developed and applied, aiming at efficient and selective removal of copper ions from aqueous solution. Compared with other methods, adsorption is widely used due to its cost-effectiveness, simple operation, good removal effect and reuse performance.

[0003] Graphene oxide has the characteristics of rich functional groups, high specific surface area and high mechanical strength, and its derived composite materials have achieved large-scale application in the field of adsorbing heavy metal ions. Using specific molecules to chemically modify graphene oxide as a base material can not only enrich the functional groups that coordinate with specific heavy metal ions, but also improve the separation performance of the composite material. In the field of efficient and selective adsorption and separation of copper ions, functionalized graphene oxide composite materials have a wider application prospect.

[0004] Therefore, the present application designs a nitrogen-rich organic molecule modified graphene oxide composite material and a preparation method and application thereof. SUMMARY

[0005] Based on this, the present application provides a nitrogen-rich organic molecule modified graphene oxide composite material and a preparation method and application thereof. The method couples 3,5-diamino-1,2,4-triazole and graphene oxide under heating conditions through nucleophilic reaction to construct a graphene oxide-based composite material with efficient adsorption of heavy metal ions and stable structure. The modification of 3,5-diamino-1,2,4-triazole can increase the amount of nitrogen elements in the composite material and increase the adsorption active sites. The modification of nitrogen-rich organic matter makes the new adsorbent have more abundant groups and adsorption sites, which can exhibit different adsorption capacities for inorganic metal cations through multiple adsorption mechanisms, thereby improving the efficient adsorption performance of the composite material and enhancing the adsorption selectivity of the composite material. The adsorption results show that it exhibits excellent adsorption selectivity for low-concentration copper ions in aqueous solution. After experiencing multiple adsorption-desorption experiments, the composite material still shows excellent reuse performance, so the composite material of the present application is expected to be applied to the separation and enrichment of low-concentration copper ions in aqueous solution.

[0006] The embodiment of the present application provides a preparation method of a nitrogen-rich organic molecule modified graphene oxide composite material, comprising the following steps:

[0007] S1: adding graphene oxide into a polar organic solvent, ultrasonic dispersion, mixing uniformly to obtain a graphene oxide dispersion;

[0008] S2: adding 3,5-diamino-1,2,4-triazole into the graphene oxide dispersion, mixing uniformly, and performing a nucleophilic reaction under weakly acidic heating conditions, and the product is repeatedly washed with ethanol and pure water, freeze-dried to obtain the nitrogen-rich organic molecule modified graphene oxide composite material. Wherein, by controlling the weakly acidic stirring until the organic molecules no longer agglomerate.

[0009] According to an aspect of the embodiment of the present application, the graphene oxide is a dry powder solid; the 3,5-diamino-1,2,4-triazole is a colorless crystal with a purity higher than 90%; and the polar organic solvent is at least one of ethanol, N,N-dimethylformamide, and dimethyl sulfoxide.

[0010] According to an aspect of the embodiment of the present application, the graphene oxide is added in an amount of 0.3-1.0 g; the 3,5-diamino-1,2,4-triazole is added in an amount of 1.0-3.0 g; and the polar organic solvent is added in an amount of 80-120.0 mL.

[0011] According to an aspect of the embodiment of the present application, the weakly acidic is obtained by adding 1.0-4.0 mL of glacial acetic acid to make the pH value of the system 4-6.

[0012] According to an aspect of the embodiment of the present application, the nucleophilic reaction is performed by using a reflux device, heated and refluxed at 80-120℃ for 8h.

[0013] According to an aspect of the embodiment of the present application, the nucleophilic reaction is always performed under stirring, and after the reaction is completed, the reaction liquid is naturally cooled to room temperature, the obtained product is suction filtered, the filter residue is repeatedly washed with 40-100 mL of ethanol for 5 times or more, and then repeatedly washed with deionized water for 5 times or more, until the supernatant is neutral, and the solid remaining on the filter membrane is collected.

[0014] Based on the general concept of the invention, the embodiment of the present application provides the nitrogen-rich organic molecule modified graphene oxide composite material obtained by the above preparation method.

[0015] The embodiment of the present application also provides the application of the nitrogen-rich organic molecule modified graphene oxide composite material obtained by the above preparation method in selective adsorption and separation of inorganic ions in an aqueous solution.

[0016] According to an aspect of the embodiment of the present application, the inorganic ions are derived from their soluble sulfate salts and nitrate salts.

[0017] According to an aspect of the embodiment of the present application, the inorganic ions include copper, lead, neodymium, cadmium, silver and yttrium, and the adsorption concentration is 10-50 mg / L.

[0018] The above scheme of the present application has the following advantages:

[0019] The present application innovatively uses 3,5-diamino-1,2,4-triazole to carry out nucleophilic reaction with graphene oxide, and uses the amino group on 3,5-diamino-1,2,4-triazole to carry out nucleophilic reaction with the carbonyl group on graphene oxide to construct a functionalized composite material with stable structure. 3,5-diamino-1,2,4-triazole can increase the number of chemical reaction sites and enhance the thermal stability of the material due to its rich nitrogen-containing functional groups. Therefore, the introduction of nitrogen-rich organic molecules as nucleophilic reagents effectively improves the adsorption capacity of the composite material. Secondly, the difference in bonding and adsorption mechanism to a certain extent makes the composite material exhibit different adsorption capacities for different inorganic ions, so as to achieve the excellent performance of selective adsorption and separation of the material. The adsorption results show that the 3,5-diamino-1,2,4-triazole coupled graphene oxide composite material provided by the present application has excellent adsorption performance for copper ions and good hydrophobic performance, and can realize selective adsorption of specific heavy metal ions and recycling after adsorption. In addition, after experiencing multiple adsorption-desorption experiments, the composite material exhibits stable physicochemical properties and can realize good recycling performance, which has high cost-effectiveness in practical application. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a comparison chart of the adsorption capacity of the 3,5-diamino-1,2,4-triazole coupled graphene oxide composite material of the embodiment of the present application for inorganic ions (copper, lead, neodymium, cadmium, silver and yttrium);

[0022] Figure 2 is a Fourier transform infrared spectrogram of different materials of the embodiment of the present application; Figure 2 (a) are Fourier transform infrared spectrograms of graphene oxide, 3,5-diamino-1,2,4-triazole coupled graphene oxide composite material before and after adsorption, respectively, Figure 2 (b) is a Fourier transform infrared spectrogram of 3,5-diamino-1,2,4-triazole.

[0023] Figure 3are scanning electron microscope images of different materials of the present application; Figure 3 (a) is SEM of graphene oxide, Figure 3 (b) is SEM of 3,5-diamino-1,2,4-triazole coupled graphene oxide composite material, Figure 3 (c) is SEM of the composite material after adsorbing copper ions.

[0024] Figure 4 are element mapping (EDS) images and distribution images of each element C, O, N of different materials of the present application; Figure 4 (a) is element mapping (EDS) image and distribution image of each element C, O, N of the composite material, Figure 4 (b) is element mapping (EDS) image and distribution image of each element C, O, N, Cu of the composite material after adsorbing copper ions.

[0025] Figure 5 are element mapping analysis images of different materials of the present application; Figure 5 (a) is element mapping analysis image of 3,5-diamino-1,2,4-triazole coupled graphene oxide composite material, Figure 5 (b) is element mapping analysis image of the composite material after adsorbing copper ions. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and advantages of the present application more clear, the following will be described in detail in combination with the drawings and specific embodiments.

[0027] Unless otherwise defined, all the professional terms used in the following have the same meaning as generally understood by those skilled in the art. The professional terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present application.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0029] The present application provides a nitrogen-rich organic molecule modified graphene oxide composite material, a preparation method and application thereof aiming at the existing problems.

[0030] Embodiment 1

[0031] The present embodiment provides a preparation method of a nitrogen-rich organic molecule modified graphene oxide composite material.

[0032] The method of the present embodiment specifically comprises the following steps:

[0033] Take 1.0 g of graphene oxide in a 250 mL round-bottom flask and add 100.0 mL of ethanol, ultrasonic for 40 minutes to mix evenly to obtain a graphene oxide dispersion, and seal for use.

[0034] Take 2 g of 3,5-diamino-1,2,4-triazole in the above-mentioned round-bottom flask, and add 1.0 mL of glacial acetic acid, slowly stir with a glass rod until the organic molecules are no longer aggregated, and obtain a mixed reaction solution for sealing.

[0035] At room temperature of about 25℃, wait for the oil bath to heat to 95℃, combine the above-mentioned round-bottom flask with the reflux device, and place it in the oil bath for reaction for 8h and continue magnetic stirring.

[0036] After the reaction is completed, the reaction solution is naturally cooled to room temperature, the obtained product is filtered under reduced pressure, the filter residue is repeatedly washed with 40-100 mL of ethanol for 5 times, and then repeatedly washed with deionized water for 5 times, until the upper clear liquid is neutral. Collect the solid residue on the filter membrane and dry to obtain a composite material.

[0037] Example 2

[0038] The embodiment provides a preparation method of a nitrogen-rich organic molecule modified graphene oxide composite material.

[0039] The method of the embodiment specifically comprises the following steps:

[0040] Take 1.0 g of graphene oxide in a 250 mL round-bottom flask and add 100.0 mL of N,N-dimethylformamide, ultrasonic for 40 minutes to mix evenly to obtain a graphene oxide dispersion, and seal for use.

[0041] Take 1 g of 3,5-diamino-1,2,4-triazole in the above-mentioned round-bottom flask, and add 1.0 mL of glacial acetic acid, slowly stir with a glass rod until the organic molecules are no longer aggregated, and obtain a mixed reaction solution for sealing.

[0042] At room temperature of about 25℃, wait for the oil bath to heat to 95℃, combine the above-mentioned round-bottom flask with the reflux device, and place it in the oil bath for reaction for 8h and continue magnetic stirring.

[0043] After the reaction is completed, the reaction solution is naturally cooled to room temperature, the obtained product is filtered under reduced pressure, the filter residue is repeatedly washed with 40-100 mL of ethanol for 5 times, and then repeatedly washed with deionized water for 5 times, until the upper clear liquid is neutral. Collect the solid residue on the filter membrane and dry to obtain a composite material.

[0044] Example 3

[0045] The embodiment provides a preparation method of a nitrogen-rich organic molecule modified graphene oxide composite material.

[0046] The method in this embodiment specifically includes the following steps:

[0047] Weigh 1.0 g of graphene oxide into a 250 mL round-bottom flask and add 100.0 mL of dimethyl sulfoxide. Sonicate for 40 minutes to mix evenly to obtain a graphene oxide dispersion. Seal the flask for later use.

[0048] Weigh 3g of 3,5-diamino-1,2,4-triazole into the round-bottom flask mentioned above, add 2.0mL of glacial acetic acid, and stir slowly with a glass rod until the organic molecules no longer agglomerate. Seal the flask with the mixture for later use.

[0049] At room temperature of around 25°C, once the oil bath reaches 95°C, the round-bottom flask and reflux device are combined and placed in the oil bath for reaction for 8 hours with continuous magnetic stirring.

[0050] After the reaction is complete, the reaction solution is naturally cooled to room temperature. The resulting product is then filtered under reduced pressure. The filter residue is washed five times with 40-100 mL of ethanol, and then five times with deionized water, until the supernatant is neutral. The solid remaining on the filter membrane is collected and dried to obtain the composite material.

[0051] The composite material prepared in the above embodiments was used as an adsorbent to adsorb inorganic ions in aqueous solution (wherein, copper ions, lead ions, neodymium ions, cadmium ions, silver ions, and yttrium ions were selected for adsorption experiments). Fourier transform infrared spectroscopy was used to analyze the chemical composition and bonding mode of the material; SEM was performed on the graphene oxide and the composite material before and after adsorption to observe the changes in surface morphology. The adsorption results and material characterization are as follows:

[0052] from Figure 1 It can be seen that the 3,5-diamino-1,2,4-triazole coupled graphene oxide composite material has excellent adsorption effect on copper ions, but almost no adsorption capacity for rare earth ions. Therefore, it can be applied to the selective adsorption and separation of copper ions from aqueous solutions.

[0053] from Figure 2 It can be seen that the synthesis of the 3,5-diamino-1,2,4-triazole-coupled graphene oxide composite material was successful. Due to the nucleophilic reaction between the 3,5-diamino-1,2,4-triazole molecule and the functional groups of graphene oxide, a more obvious characteristic absorption peak CN (1370 cm⁻¹) of the modified molecule is observed compared with the characteristic absorption peak of pure graphene oxide. -1 ) and C = N (1547cm -1 The characteristic absorption peak of the carbonyl group in the original graphene oxide, C=O (1731 cm⁻¹), appears. -1 The intensity decreased and the wavenumber was low (1688 cm⁻¹). -1The shift indicates that the primary amine on the modified molecule reacts with the carbonyl group to form hydroxylamine and immediately loses H2O to form C=N (1547 cm -1 ), which confirms that the 3,5-diamino-1,2,4-triazole coupled graphene oxide material is successfully compounded by nucleophilic reaction. Secondly, the stretching vibration of C-N and C-O-C of the composite material after adsorbing copper ions is shifted from 1370 cm -1 and 1055 cm -1 to 1378 cm -1 and 1052 cm -1 , respectively, and the stretching vibration of the amino group is red-shifted to 3205 cm -1 and 3139 cm -1 , which indicates that the composite material has good adsorption of copper ions.

[0054] It can be further seen from Figure 3 that the synthesis of the 3,5-diamino-1,2,4-triazole coupled graphene oxide material is successful, Figure 3 respectively, SEM morphology diagram of graphene oxide ( Figure 3 (a)), 3,5-diamino-1,2,4-triazole coupled graphene oxide composite material ( Figure 3 (b)), and the composite material after adsorbing copper ions. As shown in Figure 3 (a), the graphene oxide has a relatively smooth surface without curling characteristics. By Figure 2 (b), it can be observed that the 3,5-diamino-1,2,4-triazole coupled graphene oxide material retains the layered characteristics of the original GO, but the surface has obvious wrinkles and the edges form curling. After adsorbing Cu 2+ , the surface of the composite material is still partly wrinkled and relatively rough ( Figure 3 (c)). Through EDS and element mapping, it can be observed that the C, O, and N elements are uniformly distributed on the surface of the 3,5-diamino-1,2,4-triazole coupled graphene oxide material ( Figure 4 ). EDS analysis shows that the composite material contains Cu element with a mass ratio of 0.97%, which confirms that the Cu element is successfully adsorbed onto the composite material ( Figure 5 ).

[0055] The 3,5-diamino-1,2,4-triazole coupled graphene oxide material prepared by the present application has stable structure and good reusability. It has excellent adsorption performance and selectivity for copper ions, and can realize efficient selective adsorption and separation of copper ions in aqueous solution.

[0056] The above is the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles described in the present application, can also be made several improvements and refinements, these improvements and refinements should also be considered the scope of protection of the present application.

Claims

1. A method for preparing a nitrogen-rich organic molecule-modified graphene oxide composite material, characterized by, The method comprises the following steps: S1: adding graphene oxide into a polar organic solvent, ultrasonic dispersion, mixing, and obtaining a graphene oxide dispersion; S2: adding 3,5-diamino-1,2,4-triazole into the graphene oxide dispersion, mixing, and performing a nucleophilic reaction under weak acid heating conditions; the product is repeatedly washed with ethanol and pure water, freeze-dried, and graphene oxide composite material modified by the nitrogen-rich organic molecule is obtained.

2. The method for preparing a nitrogen-rich organic molecule modified graphene oxide composite according to claim 1, characterized in that, The graphene oxide is a dry powder solid; the 3,5-diamino-1,2,4-triazole is a colorless crystal with a purity higher than 90%; and the polar organic solvent is at least one of ethanol, N,N-dimethylformamide, and dimethyl sulfoxide.

3. The method for producing a nitrogen-rich organic molecule-modified graphene oxide composite material according to claim 1 or 2, characterized by, The graphene oxide is added in an amount of 0.3-1.0 g; the 3,5-diamino-1,2,4-triazole is added in an amount of 1.0-3.0 g; and the polar organic solvent is added in an amount of 80-120.0 mL.

4. The method of claim 1, wherein the nitrogen-rich organic molecule-modified graphene oxide composite is prepared by the steps of: (a) preparing a graphene oxide solution; (b) preparing a nitrogen-rich organic molecule solution; (c) mixing the graphene oxide solution and the nitrogen-rich organic molecule solution; and (d) drying the mixture to obtain the nitrogen-rich organic molecule-modified graphene oxide composite. The weak acid is obtained by adding 1.0-4.0 mL of glacial acetic acid to make the pH value of the system 4-6.

5. The method for preparing the nitrogen-rich organic molecule modified graphene oxide composite material according to claim 1, characterized in that, The nucleophilic reaction is performed by using a reflux device, heating and refluxing at 80-120 ℃ for 8 h.

6. The method for preparing the nitrogen-rich organic molecule modified graphene oxide composite material according to claim 1, characterized in that, The nucleophilic reaction is always performed under stirring, and after the reaction is completed, the reaction liquid is naturally cooled to room temperature; the obtained product is suction filtered, the filter residue is repeatedly washed with 40-100 mL of ethanol for 5 times or more, and then repeatedly washed with deionized water for 5 times or more until the upper clear liquid is neutral; and the solid remaining on the filter membrane is collected.

7. The nitrogen-rich organic molecule modified graphene oxide composite material obtained by the preparation method in any one of claims 1-6.

8. Application of the nitrogen-rich organic molecule modified graphene oxide composite material obtained by the preparation method in any one of claims 1-6 in selective adsorption and separation of copper ions in inorganic ions in an aqueous solution.

9. Use according to claim 8, characterized in that, The inorganic ions are derived from soluble sulfate salts and nitrate salts.

10. Use according to claim 8, characterized in that, The inorganic ions include copper, lead, neodymium, cadmium, silver, and yttrium, and the adsorption concentration is 10-50 mg / L.

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