An oxygen / nitrogen-rich graphene oxide composite material, a preparation method and application thereof

Abstract

The application belongs to the technical field of composite materials, and particularly discloses a graphene oxide composite material rich in oxygen / nitrogen, a preparation method and application thereof.The preparation method comprises the following steps: uniformly dispersing graphene oxide in anhydrous N,N-dimethylformamide to obtain a graphene oxide dispersion liquid; adding 2,5-diaminobenzene-1,4-diol into the graphene oxide dispersion liquid and uniformly mixing, and performing amidation reaction under the action of a catalyst; and after washing and drying the obtained product, a graphene oxide composite material rich in oxygen / nitrogen is obtained.The graphene oxide-2,5-diaminobenzene-1,4-diol composite material prepared by the application has stable structure and good reusability, has excellent adsorption performance and selectivity on p-nitrophenol, and can realize enrichment and separation of p-nitrophenol in an aqueous solution.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to an oxygen / nitrogen-rich graphene oxide composite material, a preparation method thereof, and applications thereof. Background Art

[0002] Phenolic pollutants have become a prominent problem in today's environment. They primarily originate from industrial emissions such as petrochemicals, oil refining, coke ovens, and herbicides. Phenolic pollutants are chemically and microbially stable, allowing them to persist and spread widely in the environment. Even at very low concentrations, phenolic pollutants can have negative effects on humans and aquatic life. Therefore, developing effective, cost-effective, and simple methods to remove phenolic pollutants is imperative. There are many conventional technologies for removing phenolic pollutants from wastewater, such as extraction, membrane filtration, photocatalysis, and adsorption. Among these technologies, adsorption has been extensively studied and widely used in practice due to its many advantages, including ease of operation, ease of adjustment, high efficiency, low cost, and time and labor savings.

[0003] Graphene oxide's surface and edges contain abundant functional groups, enabling adsorption of adsorbates through various intermolecular interactions. Furthermore, graphene oxide is widely used due to its high mechanical strength, large specific surface area, and stable chemical properties. Chemical modification of graphene oxide with specific molecules not only provides more active sites for the adsorption of phenolic compounds but also improves its separation performance, demonstrating broader application prospects in the field of adsorption separation.

[0004] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art. Summary of the Invention

[0005] In view of the above-mentioned shortcomings, the present invention provides an oxygen / nitrogen-rich graphene oxide composite material, a preparation method and application thereof. In the present invention, 2,5-diaminobenzene-1,4-diphenol is bonded to graphene oxide through an amidation reaction to form a graphene oxide-based composite material with a stable structure and the ability to efficiently adsorb phenolic compounds. Modification with 2,5-diaminobenzene-1,4-diphenol can increase the active sites of the composite material for adsorbing phenolic compounds, and the composite material exhibits different adsorption capacities for phenolic compounds by virtue of multiple adsorption mechanisms, thereby improving the adsorption selectivity of the composite material.

[0006] In order to achieve the above object, the present invention provides a method for preparing an oxygen / nitrogen-rich graphene oxide composite material, comprising the following steps:

[0007] S1. uniformly dispersing graphene oxide in anhydrous N,N-dimethylformamide to obtain a graphene oxide dispersion;

[0008] S2. Add 2,5-diaminobenzene-1,4-diphenol to the graphene oxide dispersion and mix them evenly, perform an amidation reaction under the action of a catalyst, and wash and dry the resulting product to obtain a composite oxygen / nitrogen-rich graphene oxide composite material.

[0009] According to one aspect of the present invention, the mass ratio of the graphene oxide to the 2,5-diaminobenzene-1,4-diphenol is 1-15:5-20.

[0010] For example, 0.1-1.5 g of graphene oxide, 50-150 mL of anhydrous N,N-dimethylformamide, and 0.5-2 g of 2,5-diaminobenzene-1,4-diphenol are uniformly dispersed and mixed by ultrasonic dispersion.

[0011] It should be noted that the graphene oxide is a dry powdered solid; the purity of the 2,5-diaminobenzene-1,4-diphenol is higher than 90%.

[0012] According to one aspect of the present invention, the mass ratio of the catalyst to the graphene oxide is 12-40:10-15.

[0013] According to one aspect of the present invention, the catalyst is O-(7-azabenzotriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) in combination with N,N-diisopropylethylamine; the mass ratio of O-(7-azabenzotriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate to N,N-diisopropylethylamine is 1-10:5-10.

[0014] For example, 0.2-2.0 g of O-(7-azabenzotriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) and 1.0-2.0 mL of N,N-diisopropylethylamine are used as the catalyst and ultrasonically stirred with the reactants until they are uniformly mixed.

[0015] According to one aspect of the present invention, in step S2, the amidation reaction is carried out in a moisture-proof reflux device, with a reaction temperature of 100 to 160° C. and a reaction time of 12 to 36 hours.

[0016] According to one aspect of the present invention, in step S2, the amidation reaction is carried out under stirring. After the reaction is completed, it is naturally cooled to room temperature. The obtained product is filtered, and the filter residue is repeatedly washed with ethanol and deionized water in sequence. After removing impurities, the filter residue is collected and freeze-dried.

[0017] For example, the amidation reaction is carried out under stirring. After the reaction is completed, the reaction solution is naturally cooled to room temperature, the obtained product is filtered, and the filter residue is repeatedly washed at least three times with 20-160 mL of ethanol and ultrapure water to collect the solid remaining on the filter membrane.

[0018] Based on the same inventive concept, the present invention also provides an oxygen / nitrogen-rich graphene oxide composite material, which is prepared by any of the above-mentioned preparation methods.

[0019] Based on the same inventive concept, the present invention also provides the use of the above-mentioned oxygen / nitrogen-rich graphene oxide composite material in the selective adsorption and separation of dyes and phenolic compounds in aqueous solution.

[0020] According to one aspect of the present invention, the dye includes at least one of methylene blue (MB) and alizarin yellow (AYR); the phenolic compound includes at least one of p-nitrophenol (PNP), m-nitrophenol (MNP), tert-butylhydroquinone (TBHQ), and hydroquinone (HQ); and the adsorbate concentration is 10 to 50 mg / L.

[0021] Beneficial effects of the present invention:

[0022] The graphene oxide of the present invention undergoes an amidation reaction with 2,5-diaminobenzene-1,4-diphenol under catalytic conditions. Specifically, the amidation reaction between the amino groups of 2,5-diaminobenzene-1,4-diphenol and the abundant carboxyl groups on the graphene oxide successfully synthesizes a structurally stable composite material. This degree of bonding has multiple advantages. On the one hand, it makes the composite material easy to separate from aqueous solutions in practical applications. On the other hand, due to the differences in the magnitude of the intermolecular forces between the composite material and different adsorbates, it exhibits different adsorption capacities. This property enables the composite material to selectively adsorb and enrich different phenolic compounds, achieving effective adsorption separation. Adsorption results show that the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material provided by the present invention has a significant adsorption effect on p-nitrophenol, while its adsorption capacity for dyes is relatively weak, making it capable of enriching and separating p-nitrophenol from aqueous solutions. In addition, the composite material has stable physical and chemical properties, which means it can achieve good reusability in practical applications, reducing the cost of the adsorption process, and providing an efficient and cost-effective solution for practical applications in related fields. The composite material of the invention has application potential in separation and enrichment of low-concentration p-nitrophenol in aqueous solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1This is a comparison chart of the adsorption capacity of the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material prepared in Example 1 of the present invention for dyes (methylene blue (MB) and alizarin yellow (AYR)) and phenolic compounds (p-nitrophenol (PNP), m-nitrophenol (MNP), tert-butylhydroquinone (TBHQ) and hydroquinone (HQ));

[0024] Figure 2 : The Fourier transform infrared spectra of the products of Example 1 and Comparative Examples 1 to 2 of the present invention; wherein A is the Fourier transform infrared spectra of the graphene oxide (GO) of Comparative Example 1 and the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material (GO-DABD) of Example 1 before and after dye adsorption; B is the Fourier transform infrared spectra of 2,5-diaminobenzene-1,4-diphenol (DABD) of Comparative Example 2;

[0025] Figure 3 are scanning electron microscope images of the products of Example 1 and Comparative Example 1 of the present invention; wherein A is a scanning electron microscope image of the graphene oxide of Comparative Example 1; B is a scanning electron microscope image of the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material of Example 1; C is a scanning electron microscope image of the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material of Example 1 after adsorbing p-nitrophenol;

[0026] Figure 4 The figures are electron scanning images, element mappings and EDS analysis images of the products of Example 1 and Comparative Example 1 of the present invention; wherein, A is an electron scanning image of the graphene oxide of Comparative Example 1 and a distribution diagram of the C and O elements; B is an electron scanning image of the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material of Example 1 and a distribution diagram of the C, O and N elements; C is an EDS analysis image of the graphene oxide of Comparative Example 1; and D is an EDS analysis image of the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material of Example 1. DETAILED DESCRIPTION

[0027] To make the present invention easier to understand, the present invention is further described below with reference to specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professional and technical personnel in this field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by known methods.

[0028] Example 1

[0029] A method for preparing an oxygen / nitrogen-rich graphene oxide composite material comprises the following steps:

[0030] 1.0 g of graphene oxide was weighed into a 250 mL round-bottom flask, and 90 mL of anhydrous N,N-dimethylformamide solution was added thereto. Ultrasonication was performed for 30 min to ensure that the graphene oxide was uniformly dispersed in the anhydrous N,N-dimethylformamide solution.

[0031] To the graphene oxide dispersion, add 1.7511 g of O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU), 1.965 mL of N,N-diisopropylethylamine, and 0.45 g of 2,5-diaminobenzene-1,4-diphenol. Stir continuously until the organic molecules no longer aggregate. Seal the mixed solution with a film and set aside.

[0032] The round-bottom flask was placed on a thermostatic magnetic stirrer and stirred at 160 °C for 36 h.

[0033] After the reaction is completed, the reaction solution is naturally cooled to room temperature, the obtained product is filtered, and the filter residue is repeatedly washed at least three times with 150 mL of ethanol and ultrapure water to collect the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material remaining on the filter membrane.

[0034] Example 2

[0035] A method for preparing an oxygen / nitrogen-rich graphene oxide composite material comprises the following steps:

[0036] 0.5 g of graphene oxide was weighed into a 250 mL round-bottom flask, 90 mL of anhydrous N,N-dimethylformamide solution was added thereto, and ultrasonication was performed for 30 min to ensure that the graphene oxide was uniformly dispersed in the anhydrous N,N-dimethylformamide solution.

[0037] To the graphene oxide dispersion, add 1.7511 g of O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU), 1.965 mL of N,N-diisopropylethylamine, and 0.45 g of 2,5-diaminobenzene-1,4-diphenol. Stir continuously until the organic molecules no longer aggregate. Seal the mixed solution with a film and set aside.

[0038] The round-bottom flask was placed on a thermostatic magnetic stirrer and stirred at 160 °C for 12 h.

[0039] After the reaction is completed, the reaction solution is naturally cooled to room temperature, the obtained product is subjected to suction filtration treatment, the filter residue is repeatedly washed with 150 mL of ethanol and ultrapure water for at least three times, and the graphene oxide-2,5-diaminobenzene-1,4-diol composite material remaining on the filter membrane is collected.

[0040] Example 3

[0041] A preparation method of an oxygen / nitrogen-rich graphene oxide composite material, comprising the following steps:

[0042] 1.5 g of graphene oxide is weighed in a 250 mL round-bottom flask, 150 mL of anhydrous N,N-dimethylformamide solution is added thereto, and ultrasonic treatment is performed for 40 min to ensure that the graphene oxide is uniformly dispersed in the anhydrous N,N-dimethylformamide solution.

[0043] 1.7511 g of O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU), 1.965 mL of N,N-diisopropylethylamine, and 0.45 g of 2,5-diaminobenzene-1,4-diol are sequentially added to the graphene oxide dispersion solution, stirring is continuously performed until the organic molecules are no longer aggregated. The mixed solution is sealed and reserved for later use.

[0044] The round-bottom flask is placed in a constant-temperature magnetic stirrer and continuously stirred at 100°C for 36 h.

[0045] After the reaction is completed, the reaction solution is naturally cooled to room temperature, the obtained product is subjected to suction filtration treatment, the filter residue is repeatedly washed with 150 mL of ethanol and ultrapure water for at least three times, and the graphene oxide-2,5-diaminobenzene-1,4-diol composite material remaining on the filter membrane is collected.

[0046] Comparative Example 1

[0047] Graphene oxide.

[0048] Comparative Example 2

[0049] 2,5-diaminobenzene-1,4-diol.

[0050] Performance detection and result analysis

[0051] The graphene oxide-2,5-diaminobenzene-1,4-diol composite material prepared in Example 1 is used as an adsorbent to adsorb dyes and phenolic compounds in an aqueous solution; the chemical composition and bonding mode of the material are analyzed by Fourier infrared spectroscopy; and the morphology of the graphene oxide and the composite material before and after adsorption is observed by SEM. The material adsorption results and material characterization are as follows:

[0052] From Figure 1It can be seen that the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material has an obvious adsorption effect on p-nitrophenol, but a poor adsorption effect on dyes, so it can be applied to the separation of p-nitrophenol from aqueous solution.

[0053] from Figure 2 It can be seen that the amidation of graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material is successful. Due to the amidation reaction between 2,5-diaminobenzene-1,4-diphenol molecules and graphene oxide functional groups, there is a more obvious characteristic absorption peak of the modified molecule compared with the characteristic absorption peak of pure graphene oxide. At the same time, the C=O (1730.35cm -1 ) stretching vibration to the low wave number 1657.80cm -1 Move, in addition, at 1442.30cm -1 A new stretching vibration absorption peak is generated at 3430.68 cm-1, which is the stretching vibration of CN in amide. Based on the above analysis, the successful preparation of graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material is confirmed. After adsorption of p-nitrophenol, the stretching vibration of OH / NH and the aromatic ring skeleton vibration increase from 3430.68 cm-1 to 3430.68 cm-1, respectively. -1 and 1628.35cm -1 Move to 3439.12cm -1 and 1633.64cm -1 , indicating that hydrogen bonding and π-π stacking occurred between the composite material and p-nitrophenol.

[0054] from Figure 3 It can be seen that the synthesis of graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material is successful. Figure 3 Graphene oxide ( Figure 3 A), graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material ( Figure 3 B), graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material after adsorption ( Figure 3 C) SEM morphology. Figure 3As shown, the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite retains the lamellar structure of graphene oxide. Furthermore, the covalent coupling of 2,5-diaminobenzene-1,4-diphenol molecules to the graphene oxide surface results in a thicker and rougher surface. Adsorption of p-nitrophenol did not significantly alter its surface properties. Elemental mapping and EDS analysis of the elemental distribution and composition of the surfaces of graphene oxide and the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite revealed that C (72.88 wt.%), O (14.29 wt.%), and N (12.84 wt.%) were detected in the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite. The presence of N further indicates successful modification of the 2,5-diaminobenzene-1,4-diphenol molecules. Furthermore, the relatively uniform distribution of N and O on the composite surface facilitates the adsorption of p-nitrophenol.

[0055] In summary, the graphene oxide-2,5-diaminobenzene-1,4-diphenol composite material prepared by the present invention has a stable structure and good reusability. It has excellent adsorption performance and selectivity for p-nitrophenol and can achieve the enrichment and separation of p-nitrophenol in aqueous solution.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing an oxygen / nitrogen-rich graphene oxide composite material, characterized in that: The following steps are involved: S1. uniformly dispersing graphene oxide in anhydrous N,N-dimethylformamide to obtain a graphene oxide dispersion; S2. Add 2,5-diaminobenzene-1,4-diphenol to the graphene oxide dispersion and mix them evenly, carry out amidation reaction under the action of a catalyst, and wash and dry the resulting product to obtain a composite oxygen / nitrogen-rich graphene oxide composite material; wherein the catalyst is O-(7-azabenzotriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate in combination with N,N-diisopropylethylamine; the mass ratio of the O-(7-azabenzotriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate to N,N-diisopropylethylamine is 1~10:5~10.

2. The method for preparing the oxygen / nitrogen-rich graphene oxide composite material according to claim 1, wherein The mass ratio of the graphene oxide to the 2,5-diaminobenzene-1,4-diphenol is 1-15:5-20.

3. The method for preparing the oxygen / nitrogen-rich graphene oxide composite material according to claim 1, wherein The mass ratio of the catalyst to the graphene oxide is 12-40:10-15.

4. The method for preparing the oxygen / nitrogen-rich graphene oxide composite material according to claim 1, wherein In step S2, the amidation reaction is carried out in a moisture-proof reflux device, the reaction temperature is 100-160°C, and the reaction time is 12-36 hours.

5. The method for preparing the oxygen / nitrogen-rich graphene oxide composite material according to claim 1, wherein: In step S2, the amidation reaction is carried out under stirring. After the reaction is completed, the mixture is naturally cooled to room temperature. The obtained product is filtered, and the filter residue is repeatedly washed with ethanol and deionized water in sequence. After removing impurities, the filter residue is collected and freeze-dried.

6. An oxygen / nitrogen-rich graphene oxide composite material, characterized in that Prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the oxygen / nitrogen-rich graphene oxide composite material according to claim 6 in the selective adsorption and separation of dyes and phenolic compounds in aqueous solution.

8. The use according to claim 7, characterized in that The dye includes at least one of methylene blue and alizarin yellow; the phenolic compound includes at least one of p-nitrophenol, m-nitrophenol, tert-butylhydroquinone, and hydroquinone; and the adsorbate concentration is 10-50 mg / L.

Images