Aminated graphene, preparation method and application of aminated graphene in degradation of organic wastewater

Abstract

The invention belongs to the field of catalyst preparation, and discloses aminated graphene, a preparation method and application of aminated graphene in degradation of organic wastewater, the preparation method comprises the following steps: reacting graphene oxide with organic amine to obtain a dispersion liquid; and washing, freezing and freeze-drying the dispersion liquid to obtain the aminated graphene. Compared with a metal catalyst, the catalyst has the advantages that secondary pollution is reduced when the catalyst is used for degrading organic matters in an advanced oxidation system, the secondary treatment cost is reduced, and the sustainable development strategy is met. Compared with a common catalyst, the catalyst has excellent organic matter degradation performance under the condition that the pH range is 1-11, and has a very good practical application scene.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic wastewater treatment, and in particular relates to ammoniated graphene, a preparation method thereof, and an application thereof in degrading organic wastewater. Background Art

[0002] With the rapid development of global industrialization, particularly the rapid expansion of industries like pharmaceuticals, chemicals, and petroleum refining, the discharge of industrial wastewater has increased significantly, containing a large number of recalcitrant organic pollutants. These organic pollutants, including phenolic compounds, polycyclic aromatic hydrocarbons, and pesticide residues, are highly toxic, difficult to degrade, and prone to bioaccumulation. If discharged directly into the aquatic environment without proper treatment, they can not only damage aquatic ecosystems but also accumulate in the food chain, ultimately endangering human health.

[0003] Take phenol, for example. As an important industrial raw material and disinfectant, it is widely present in wastewater from the pharmaceutical, chemical, and dye industries. Phenol is highly toxic and carcinogenic. Long-term exposure to low concentrations of phenol can lead to chronic poisoning, causing serious damage to the human nervous system, liver, and kidneys. The World Health Organization has listed phenol as a priority environmental pollutant. Therefore, the development of efficient and cost-effective phenol wastewater treatment technologies has become a research hotspot in the field of environmental engineering.

[0004] Among many water treatment technologies such as electrochemical oxidation, wet air oxidation and supercritical water oxidation, the high cost and poor economic benefits make the advanced oxidation technology based on peroxymonosulfate attract much attention due to its advantages of high efficiency, economy, rapidity and no secondary pollution. The core of the advanced oxidation technology based on peroxymonosulfate is to activate peroxymonosulfate to produce active species with strong oxidizing ability, such as sulfate radicals, hydroxyl radicals, etc. These active species can quickly degrade organic pollutants and even mineralize them into carbon dioxide and water. The activation pathways of peroxymonosulfate mainly include free radical pathways and non-free radical pathways: the free radical pathway depends on the activation of transition metals (such as Co 2+ 、Fe 2+ ) or carbon-based materials catalyze peroxymonosulfate to produce free radicals; while non-radical pathways achieve pollutant degradation through electron transfer or the generation of singlet oxygen.

[0005] However, peroxymonosulfate-based advanced oxidation technologies face many challenges in treating organic pollutants under different pH conditions. In acidic environments, although peroxymonosulfate can achieve efficient degradation mainly through free radical pathways, high concentrations of H +It will inhibit the dissociation of peroxymonosulfate and cause the active components of the transition metal catalyst to dissolve, causing secondary pollution and reducing the catalytic efficiency. Under alkaline conditions, peroxymonosulfate tends to react through a non-radical mechanism, but the reaction kinetics are slow, and peroxymonosulfate easily decomposes spontaneously into SO42- and O2, resulting in a waste of oxidant. In addition, changes in pH will significantly affect the existence form of organic pollutants and their reactivity with active species, which may lead to changes in degradation pathways and the accumulation of toxic intermediates. The stability problem of the catalyst also runs through the entire pH range. Metal dissolution under acidic conditions and hydroxide precipitation under alkaline conditions will lead to catalyst deactivation. In actual water bodies, complex matrix components such as dissolved organic matter and various anions will further interfere with the activation process of peroxymonosulfate.

[0006] The pH value of wastewater from different industries varies significantly. Traditional technologies such as biological methods and Fenton require frequent pH adjustments, which increases costs and operational difficulty. Summary of the Invention

[0007] In response to the problem that catalysts in the prior art cannot be applied to the degradation of organic matter in organic wastewater with different pH ranges, resulting in low organic matter degradation efficiency, the purpose of the present invention is to provide an amino-modified graphene, a preparation method and an application for degrading organic wastewater. This material can maintain stable catalytic performance in complex environments of strong acids, strong bases and multiple anions.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing amination-modified graphene comprises the following steps:

[0010] reacting graphene oxide and organic amine to obtain a dispersion;

[0011] The dispersion is washed, frozen and freeze-dried to obtain amino-treated graphene.

[0012] Furthermore, the mass ratio of graphene oxide to organic amine is 1:8-1:32.

[0013] Furthermore, the organic amine is ethylenediamine, diethylenetriamine, 3-aminopropyltriethoxysilane, N-[3-(trimethoxysilyl)propyl], dopamine, p-phenylenediamine, aniline or pyridinamine.

[0014] Furthermore, the reaction temperature is 60-200° C., and the reaction time is 4-24 h.

[0015] An amino-modified graphene.

[0016] The invention discloses an application of amino-modified graphene in organic wastewater with a pH range of 1-11.

[0017] Furthermore, the amino-modified graphene is added to an aqueous solution of phenol, stirred after ultrasonication, and then peroxymonosulfate is added and the phenol is degraded under stirring.

[0018] Furthermore, the amino-treated graphene is added to an aqueous solution of phenol with a pH of 1-11, stirred after ultrasonication, and then peroxymonosulfate is added and the phenol is degraded under stirring.

[0019] Furthermore, the amino-treated graphene is added to an aqueous solution of phenol containing KCl, K2CO3 or KHCO3, stirred after ultrasonication, and then peroxymonosulfate is added and the phenol is degraded under stirring.

[0020] Furthermore, the amino-modified graphene is added to an aqueous solution of rhodamine B, p-chlorophenol or sulfamethoxazole, stirred after ultrasonication, and then peroxymonosulfate is added and the organic matter is degraded under stirring.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention uses organic amine and graphene oxide synthesis catalyst to prepare amination graphene, for the catalyst in the prior art degrading organic matter under the conditions of pH range 1-11, overcomes the problem that the free radical generation mechanism is changed in a strong acid and strong base environment, the free radical pathway is converted into a non-free radical pathway, the catalyst will be excessively dissolved or complexed and precipitated to make the organic matter degradation efficiency low, the amination graphene prepared by the present invention is through the free radical pathway of superoxide radical, hydroxyl radical and sulfate radical and singlet oxygen, amination graphene to peroxymonosulfate electron transfer activation peroxymonosulfate non-free radical pathway synergistic effect can maintain stable catalytic performance in a complex environment of strong acid, strong base and various anions, thereby significantly improving its applicability and practicality in the advanced oxidation technology based on peroxymonosulfate. Compared with metal catalysts, this catalyst degrades organic matter in an advanced oxidation system, reduces secondary pollution, reduces secondary governance costs, and is in line with the sustainable development strategy. Compared with existing catalysts, this catalyst has excellent organic matter degradation performance under the conditions of pH range 1-11, and has good practical application scenarios. DETAILED DESCRIPTION

[0023] The following describes preferred embodiments of the present invention in conjunction with embodiments. It should be understood that the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] The preparation method of the amination graphene of the present invention comprises the following steps:

[0025] (1) Graphene oxide and organic amine are reacted in a certain proportion at a certain temperature and for a certain reaction time to obtain a black dispersion.

[0026] The mass ratio of graphene oxide to organic amine is 1:8-1:32.

[0027] Organic amines include ethylenediamine, diethylenetriamine, 3-aminopropyltriethoxysilane, N-[3-(trimethoxysilyl)propyl], dopamine, p-phenylenediamine, aniline and pyridinamine.

[0028] The reaction temperature is 60-200°C, and the reaction time is 4-24h.

[0029] (2) Washing the black dispersion obtained in step (1) from alkaline to neutral, first with anhydrous ethanol and then with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst, amination graphene.

[0030] The amino-functionalized non-metallic carbon material amination graphene catalyst prepared by the method is used in degrading organic wastewater with a pH range of 1-11 based on an advanced oxidation technology of peroxymonosulfate.

[0031] Example 1

[0032] (1) Graphene oxide and organic amine are reacted at a certain ratio at 100°C for 6 hours.

[0033] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:8.

[0034] Furthermore, the organic amine in step (1) is ethylenediamine.

[0035] (2) Washing the product obtained in step (1) from alkaline to neutral, first with anhydrous ethanol and then with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0036] Example 2

[0037] (1) Graphene oxide and organic amine are reacted at a certain ratio at 60°C for 24 hours.

[0038] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:32.

[0039] Furthermore, the organic amine in step (1) is 3-aminopropyltriethoxysilane.

[0040] (2) Washing the product obtained in step (1) from alkaline to neutral, first with anhydrous ethanol and then with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0041] Example 3

[0042] (1) Graphene oxide and organic amine are reacted at a certain ratio at 200°C for 4 hours.

[0043] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:30.

[0044] Furthermore, the organic amine in step (1) is N-[3-(trimethoxysilyl)propyl].

[0045] (2) Washing the product obtained in step (1) from alkaline to neutral, first with anhydrous ethanol and then with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0046] Example 4

[0047] (1) Graphene oxide and organic amine are reacted at a certain ratio at 150°C for 10 hours.

[0048] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:25.

[0049] Furthermore, the organic amine in step (1) is dopamine.

[0050] (2) Washing the product obtained in step (1) from alkaline to neutral, first with anhydrous ethanol and then with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0051] Example 5

[0052] (1) Graphene oxide and organic amine are reacted at a certain ratio at 80°C for 20 hours.

[0053] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:20.

[0054] Furthermore, the organic amine in step (1) is p-phenylenediamine.

[0055] (2) Washing the product obtained in step (1) from alkaline to neutral, first with anhydrous ethanol and then with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0056] Example 6

[0057] (1) Graphene oxide and organic amine are reacted at a certain ratio at 120°C for 16 hours.

[0058] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:15.

[0059] Furthermore, the organic amine in step (1) is aniline.

[0060] (2) Washing the product obtained in step (1) from alkaline to neutral, first with anhydrous ethanol and then with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0061] Example 7

[0062] (1) Graphene oxide and organic amine are reacted at a certain ratio at 180°C for 6 hours.

[0063] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:13.

[0064] Furthermore, the organic amine in step (1) is pyridinamine.

[0065] (2) Washing the product obtained in step (1) from alkaline to neutral, first washing with anhydrous ethanol and then washing with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0066] Example 8

[0067] (1) Graphene oxide and organic amine are reacted at a certain ratio at 100°C for 6 hours.

[0068] Furthermore, in step (1), the mass ratio of graphene oxide to organic amine is 1:10.

[0069] Furthermore, the organic amine in step (1) is diethylenetriamine.

[0070] (2) Washing the product obtained in step (1) from alkaline to neutral, first washing with anhydrous ethanol and then washing with deionized water. Freezing the washed product, and then freeze-drying it to obtain the final catalyst amination graphene.

[0071] Comparative Example 1

[0072] Graphene oxide was used as a comparative example.

[0073] The experimental method for the degradation of phenol by a specific catalyst in the present invention comprises the following steps:

[0074] (1) Experimental method and conditions for the degradation of phenol by amination graphene and graphene oxide catalysts (see Table 1): Pour 100 mL of 20 mg / L phenol solution into a 100 mL reactor, stir evenly, take a 0.5 mL sample and mix it with 0.5 mL of methanol in a 1.5 mL centrifuge tube and name it -30 min. Weigh 20 mg of catalyst (amination graphene or graphene oxide) and add it to the reactor for ultrasonication for 5 min, stir for 25 min, take a 0.5 mL sample and mix it with 0.5 mL of methanol in a 1.5 mL centrifuge tube and name it 0 min. Then add 50 mg of peroxymonosulfate, stir and start timing, take samples at 2 min, 5 min, 10 min, 15 min, 20 min, 30 min, 40 min, and 60 min, take a 0.5 mL sample and mix it with 0.5 mL of methanol in a 1.5 mL centrifuge tube and name it 0 min. All samples were filtered with a 0.22 μm nylon needle filter into high performance liquid chromatography sample bottles. All stirring reactions were performed in a 25°C water bath. Phenol concentration was determined by HPLC. The mobile phase for phenol was acetonitrile and ultrapure water in a 4:6 volume ratio. The detection wavelength was 220 nm, the column temperature was 40°C, and the mobile phase flow rate was 1 mL / L.

[0075] (2) Experimental method and conditions for phenol degradation by amination graphene at different pH values ​​(see Table 2): Pour 100 mL of 20 mg / L phenol solution into a 100 mL reactor (adjust the pH to 1, 3, 5, 9, and 11 with hydrochloric acid or NaOH), stir evenly, take a 0.5 mL sample and mix evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube and name it -30 min. Weigh 20 mg of amination graphene and add it to the reactor and ultrasonicate for 5 min. Stir for 25 min. Take a 0.5 mL sample and mix evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube and name it 0 min. Then add 50 mg of peroxymonosulfate, stir and start timing. Take samples at 2 min, 5 min, 10 min, 15 min, 20 min, 30 min, 40 min, and 60 min. Take a 0.5 mL sample and mix evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube. All samples were filtered through a 0.22 μm nylon syringe filter into HPLC vials. Stirring reactions were performed in a 25°C water bath. Phenol concentration was determined by HPLC. The mobile phase consisted of acetonitrile and ultrapure water in a 4:6 volume ratio. The detection wavelength was 220 nm, the column temperature was 40°C, and the mobile phase flow rate was 1 mL / L.

[0076] (3) Experimental method and conditions for phenol degradation by amination graphene under different anions (see Table 3): Pour 100 mL of 20 mg / L phenol solution (containing 1 mmol / L KCl, K2CO3 or KHCO3) into a 100 mL reactor and stir evenly. Take a 0.5 mL sample and mix it evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube and name it -30 min. Weigh 20 mg of amination graphene into a bottle reactor and ultrasonicate for 5 min. Stir for 25 min. Take a 0.5 mL sample and mix it evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube and name it 0 min. Then add 50 mg of peroxymonosulfate, stir and start timing. Take samples at 2 min, 5 min, 10 min, 15 min, 20 min, 30 min, 40 min, and 60 min. Take a 0.5 mL sample and mix it evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube. All samples were filtered through a 0.22 μm nylon syringe filter into HPLC vials. Stirring reactions were performed in a 25°C water bath. Phenol concentration was determined by HPLC. The mobile phase for phenol was a 4:6 volume ratio of acetonitrile and ultrapure water. The detection wavelength was 220 nm, the column temperature was 40°C, and the mobile phase flow rate was 1 mL / L.

[0077] (3) Experimental method conditions for degradation of different pollutants by amino graphene (see Table 4): 20 mg / L organic pollutant solution of rhodamine B, p-chlorophenol or sulfamethoxazole was poured into a 100 mL reactor and stirred evenly. 0.5 mL of the sample was mixed evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube and named -30 min. 20 mg of amino graphene was weighed and added to the reactor and ultrasonicated for 5 min. Stirred for 25 min. 0.5 mL of the sample was mixed evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube and named 0 min. 50 mg of peroxymonosulfate was then added. Stirring began to time the sample. Samples were taken at 2 min, 5 min, 10 min, 15 min, 20 min, 30 min, 40 min, and 60 min. 0.5 mL of the sample was mixed evenly with 0.5 mL of methanol in a 1.5 mL centrifuge tube. All samples were filtered with a 0.22 μm nylon needle filter into high performance liquid chromatography sample bottles. All stirring reactions were carried out in a 25°C water bath. The concentrations of rhodamine B, p-chlorophenol, and sulfamethoxazole were determined by HPLC. The mobile phase for rhodamine B consisted of a 7:3 volume ratio of methanol to ultrapure water, with a detection wavelength of 550 nm, a column temperature of 40°C, and a mobile phase flow rate of 1 mL / L. The mobile phase for p-chlorophenol consisted of a 7:3 volume ratio of methanol to ultrapure water, with a detection wavelength of 280 nm, a column temperature of 40°C, and a mobile phase flow rate of 1 mL / L. The mobile phase for sulfamethoxazole consisted of a 7:3 volume ratio of methanol to ultrapure water (0.1% phosphoric acid), with a detection wavelength of 256 nm, a column temperature of 40°C, and a mobile phase flow rate of 0.6 mL / L.

[0078] Table 1 shows the degradation performance of the amination graphene of Example 1 and the graphene oxide of Comparative Example 1, with the catalyst dosage of 20 mg and 50 mg of peroxymonosulfate for the reaction of 20 mg / L phenol in a 100 mL stirred reactor. The degradation efficiency is quantified by C / C0, where C represents the concentration of the sample taken at a certain moment and C0 represents the concentration of the initial phenol solution. Without the introduction of amino groups, the graphene oxide showed negligible phenol degradation activity, which indicates that the unmodified graphene oxide lacks inherent catalytic activity for phenol degradation. When the amino-functionalized catalyst amination graphene was introduced into the reaction system, its performance showed significant differences. The catalytic activity of amino groups in the surface-based peroxymonosulfate-based advanced oxidation technology is significantly affected by the properties of the support material. As shown in Table 1, the catalytic performance of the amination graphene reached a phenol degradation rate of about 80% within 60 minutes. This significant improvement directly illustrates that the catalytic activity of the amino group is affected by the properties of the support material. There are many limitations to the degradation of organic matter by the catalyst in the pH range of 1-11.

[0079] To evaluate the degradation of organic matter by amination-modified graphene within a pH range of 1-11, the present invention studied the degradation of phenol by amination-modified graphene within this pH range. Table 2 shows that under strong acid conditions of pH 1, phenol degradation by the present invention reached 93.98% within 20 minutes, with complete degradation achieved within 30 minutes. Furthermore, under strong alkaline conditions of pH 11, phenol degradation reached 95.16% within 40 minutes, with near-complete degradation achieved within 60 minutes. Furthermore, under weak acid, weak base, and neutral conditions, phenol degradation exceeded 80% within 60 minutes. This demonstrates that the present invention exhibits excellent phenol degradation across a pH range of 1-11.

[0080] In order to evaluate the wider applicability of amination graphene, the present invention also studied the effectiveness of amination graphene in pollutant degradation under different anions (see Table 3) and different pollutants (see Table 4). From Tables 3 and 4, it was found that amination graphene also showed strong activity in the degradation of phenol in the presence of other anions, with the degradation of phenol exceeding 90% in 60 minutes, CO3 2- and HCO3 - Phenol was almost completely degraded within 60 minutes. The degradation efficiency for common hard-to-degrade organic pollutants, such as rhodamine B, sulfamethoxazole, and para-chlorophenol, also exceeded 90%, demonstrating excellent results and the wide applicability of this catalyst.

[0081] Table 1 Degradation rate of phenol in different embodiments and comparative examples (%)

[0082]

[0083] Table 2 Phenol degradation rate of amino graphene at different pH values ​​(%)

[0084]

[0085] Table 3 Phenol degradation rate of amino graphene under different anions (%)

[0086]

[0087] Table 4 Degradation rate of amino-modified graphene on different pollutants (%)

[0088]

[0089] The above description is merely a description of the preferred embodiment of the present invention and is not to be construed as limiting the claims. The present invention is not limited to the above embodiment, and variations in the specific structure are permitted. Any variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0090] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for preparing ammoniated graphene, characterized in that: The steps include: reacting graphene oxide and organic amine to obtain a dispersion; The dispersion is washed, frozen and freeze-dried to obtain amino-treated graphene.

2. The method for preparing amination-modified graphene according to claim 1, wherein: The mass ratio of graphene oxide to organic amine is 1:8-1:

32.

3. The method for preparing amination-modified graphene according to claim 1, wherein: The organic amine is ethylenediamine, diethylenetriamine, 3-aminopropyltriethoxysilane, N-[3-(trimethoxysilyl)propyl], dopamine, p-phenylenediamine, aniline or pyridinamine.

4. The method for preparing amination-modified graphene according to claim 1, wherein: The reaction temperature is 60-200°C, and the reaction time is 4-24h.

5. An amination-modified graphene prepared according to the method according to any one of claims 1 to 4.

6. Use of the aminated graphene prepared according to the method according to any one of claims 1 to 4 in degrading organic wastewater in the pH range of 1-11.

7. The use according to claim 6, characterized in that The amino-modified graphene was added to a phenol aqueous solution, stirred after ultrasonication, and then peroxymonosulfate was added and the phenol was degraded under stirring.

8. The use according to claim 6, characterized in that The aminated graphene is added to an aqueous solution of phenol with a pH of 1-11, stirred after ultrasonication, and then peroxymonosulfate is added and the phenol is degraded under stirring.

9. The use according to claim 6, characterized in that The aminated graphene is added to an aqueous solution of phenol containing KCl, K2CO3 or KHCO3, stirred after ultrasonication, and then peroxymonosulfate is added and the phenol is degraded under stirring.

10. The use according to claim 6, characterized in that The amino-modified graphene was added to an aqueous solution of rhodamine B, p-chlorophenol or sulfamethoxazole, stirred after ultrasonication, and then peroxymonosulfate was added and the organic matter was degraded under stirring.

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