Graphene composite-based sewage treatment agent and preparation method thereof

Abstract

This invention discloses a wastewater treatment agent based on graphene composite materials and its preparation method, belonging to the field of wastewater treatment technology. The method involves crosslinking cyclodextrin into a network macromolecule, combining it with adamantane-modified graphene, and utilizing host-guest complexation to prepare the composite material. The preparation method of this invention is simple, the raw materials are readily available, and it exhibits efficient adsorption of common heavy metal ions in wastewater. It can be effectively applied in the field of wastewater treatment and has good application prospects.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically a wastewater treatment agent based on graphene composite materials and its preparation method. Background Technology

[0002] With rapid industrial development, the pollution problem of heavy metal ions in wastewater has become increasingly serious, posing a significant threat to human health and the ecological environment. Graphene, a two-dimensional material composed of carbon atoms in a hexagonal monolayer structure, possesses excellent adsorption properties. Furthermore, the surface of graphene contains numerous functional groups and active sites, enabling it to strongly interact with heavy metal ions. It exhibits good removal effects for heavy metal ions such as copper, lead, and cadmium, and has wide applications in wastewater treatment.

[0003] However, graphene also has certain limitations in practical applications. First, graphene is prone to agglomeration in water, leading to a decrease in adsorption performance. Second, graphene has poor cycle stability, easily experiencing structural collapse and loss of functional groups during recycling, thus affecting the recyclability of graphene materials. Therefore, improving the dispersibility and stability of graphene in wastewater by combining it with other materials is of great significance for enhancing its performance in wastewater treatment. Summary of the Invention

[0004] To address the above problems, the present invention aims to provide a wastewater treatment agent based on graphene composite materials and its preparation method.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A wastewater treatment agent based on graphene composite material, comprising, by weight, 1 to 1.5 parts of cyclodextrin cross-linked network macromolecules and 1 part of adamantane-modified graphene.

[0007] The cyclodextrin cross-linked network macromolecules were prepared according to the following method:

[0008] Octa(6-bromo-6-deoxy)-γ-cyclodextrin and 2-aminohydroquinone were added to an organic solvent and stirred until homogeneous. Then, an inorganic basic compound was added and the mixture was heated to 50-100°C for 5-10 hours. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed 2-3 times with a mixed solvent of ethanol and water in a volume ratio of 1:1 and dried to obtain cyclodextrin cross-linked network macromolecules.

[0009] The preparation method of the adamantane-modified graphene includes the following steps:

[0010] 1) Add graphene oxide to water and sonicate for 0.5-1 h. Then add chloroacetic acid and sodium hydroxide and sonicate for 0.5-1 h. Stir and react for 12-24 h. Filter the mixture and wash the resulting filter cake with water until neutral. Dry it under vacuum at 60 °C to obtain carboxylated graphene oxide.

[0011] 2) Add the carboxylated graphene oxide and adamantane obtained in step 1) to an organic solvent, stir and mix evenly, then add diethyl azodicarbonate and 1-hydroxybenzotriazole, and react at 25-40℃ for 8-15 h. After the reaction is complete, remove the solvent by vacuum distillation, wash the residue with acetone 2-3 times, and dry to obtain adamantane-modified graphene.

[0012] The organic solvent is dimethyl sulfoxide or dimethylformamide.

[0013] The inorganic alkaline compound is potassium carbonate, sodium carbonate, potassium hydroxide, or sodium hydroxide.

[0014] The mass ratio of the octa(6-bromo-6-deoxy)-γ-cyclodextrin, 2-aminohydroquinone, organic solvent, and inorganic basic compound is 1:0.3-0.5:5-10:0.6-0.8.

[0015] The mass ratio of graphite oxide, water, chloroacetic acid, and sodium hydroxide in step 1) is 1:200-300:5-10:3-6.

[0016] In step 2), the mass ratio of carboxylated graphene oxide, adamantane, organic solvent, diethyl azodicarbonate, and 1-hydroxybenzotriazole is 1:0.3–1:10–15:0.5–1.5:0.3–0.8.

[0017] The method for preparing the wastewater treatment agent based on graphene composite material involves, by weight, adding 1-1.5 parts of cyclodextrin cross-linked network macromolecules and 1 part of adamantane-modified graphene to 30-50 parts of water, dispersing them evenly, heating to 40-50°C, stirring for 12-24 hours, filtering, and drying to obtain the wastewater treatment agent based on graphene composite material.

[0018] The present invention also includes the application of wastewater treatment agents based on graphene composite materials in the adsorption of heavy metal ions in wastewater.

[0019] The present invention has the following advantages over the prior art:

[0020] The wastewater treatment agent based on graphene composite material of the present invention crosslinks cyclodextrin into a network macromolecule, combines it with adamantane-modified graphene, and prepares the composite material by utilizing host-guest complexation. The network structure of cyclodextrin provides support for the material, preventing the collapse of the graphene structure and increasing the mechanical strength and stability of the material. At the same time, the host-guest complexation between cyclodextrin and adamantane enhances the interaction between graphene molecules, inhibits the aggregation of graphene in water, thereby improving its dispersibility in water and enhancing its adsorption performance.

[0021] The wastewater treatment agent based on graphene composite materials of the present invention is prepared by obtaining a cyclodextrin cross-linked network macromolecule and introducing amine groups. On the one hand, the structure of the cross-linked network macromolecule gives it a large specific surface area and porosity, increasing the adsorption sites; on the other hand, the amine groups can form coordination bonds with heavy metal ions, increasing the adsorption of metal ions. By using adamantane to modify graphene, the introduced amide groups can interact with heavy metal ions through hydrogen bonds, further enhancing its adsorption capacity.

[0022] The wastewater treatment agent based on graphene composite material of the present invention has a simple preparation method, the raw materials are easy to obtain, and it has a high efficiency adsorption effect on common heavy metal ions in wastewater. It can be effectively applied in the field of wastewater treatment and has good application prospects. Detailed Implementation

[0023] To better understand the technical solution of the present invention, the following detailed embodiments further illustrate the above-mentioned content of the present invention. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following examples. All technologies implemented based on the above-mentioned content of the present invention fall within the scope of the present invention.

[0024] Example 1: Preparation of cyclodextrin cross-linked network macromolecules

[0025] 0.1 kg of octa(6-bromo-6-deoxy)-γ-cyclodextrin and 0.03 kg of 2-aminohydroquinone were added to 0.5 kg of dimethyl sulfoxide and stirred until homogeneous. Then, 0.06 kg of sodium hydroxide was added and the mixture was heated to 50 °C for 5 h. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed twice with a 1:1 mixture of ethanol and water and dried to obtain a cyclodextrin cross-linked network macromolecule.

[0026] Preparation of adamantane-modified graphene

[0027] 1) Add 0.1 kg of graphite oxide to 20 kg of water, sonicate for 0.5 h, then add 0.5 kg of chloroacetic acid and 0.3 kg of sodium hydroxide, sonicate for 0.5 h, stir and react for 12 h, filter, wash the resulting filter cake with water until neutral, and vacuum dry at 60 °C to obtain carboxylated graphene oxide.

[0028] 2) Add 0.1 kg of carboxylated graphene oxide and 0.03 kg of adamantane to 1 kg of dimethylformamide, stir and mix evenly, then add 0.05 kg of diethyl azodicarbonate and 0.03 kg of 1-hydroxybenzotriazole, and react at 25 °C for 8 h. After the reaction is complete, remove the solvent by vacuum distillation, wash the residue twice with acetone, and dry to obtain adamantane-modified graphene.

[0029] Preparation of wastewater treatment agents based on graphene composite materials

[0030] 1 kg of cyclodextrin cross-linked network macromolecules and 1 kg of adamantane-modified graphene were added to 30 kg of water, dispersed evenly, heated to 40 °C, stirred for 12 h, filtered, and dried to obtain a wastewater treatment agent based on graphene composite material.

[0031] Example 2: Preparation of cyclodextrin cross-linked network macromolecules

[0032] 0.1 kg of octa(6-bromo-6-deoxy)-γ-cyclodextrin and 0.035 kg of 2-aminohydroquinone were added to 0.6 kg of dimethylformamide and stirred until homogeneous. Then, 0.065 kg of sodium carbonate was added, and the mixture was heated to 60 °C for 8 h. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed three times with a 1:1 mixture of ethanol and water and dried to obtain a cyclodextrin cross-linked network macromolecule.

[0033] Preparation of adamantane-modified graphene

[0034] 1) Add 0.1 kg of graphite oxide to 22 kg of water, sonicate for 0.6 h, then add 0.6 kg of chloroacetic acid and 0.4 kg of sodium hydroxide, sonicate for 0.7 h, stir and react for 15 h, filter, wash the resulting filter cake with water until neutral, and vacuum dry at 60 °C to obtain carboxylated graphene oxide.

[0035] 2) Add 0.1 kg of carboxylated graphene oxide and 0.05 kg of adamantane to 1.1 kg of dimethylformamide, stir and mix evenly, then add 0.07 kg of diethyl azodicarbonate and 0.04 kg of 1-hydroxybenzotriazole, and react at 30 °C for 10 h. After the reaction is complete, remove the solvent by vacuum distillation, wash the residue three times with acetone, and dry to obtain adamantane-modified graphene.

[0036] Preparation of wastewater treatment agents based on graphene composite materials

[0037] 1.1 kg of cyclodextrin cross-linked network macromolecules and 1 kg of adamantane-modified graphene were added to 35 kg of water, dispersed evenly, heated to 42 °C, stirred for 15 h, filtered, and dried to obtain a wastewater treatment agent based on graphene composite material.

[0038] Example 3: Preparation of cyclodextrin cross-linked network macromolecules

[0039] 0.1 kg of octa(6-bromo-6-deoxy)-γ-cyclodextrin and 0.04 kg of 2-aminohydroquinone were added to 0.8 kg of dimethylformamide and stirred until homogeneous. Then, 0.07 kg of sodium carbonate was added, and the mixture was heated to 80 °C for 7.5 h. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed three times with a 1:1 mixture of ethanol and water and dried to obtain a cyclodextrin cross-linked network macromolecule.

[0040] Preparation of adamantane-modified graphene

[0041] 1) Add 0.1 kg of graphite oxide to 25 kg of water, sonicate for 0.8 h, then add 0.7 kg of chloroacetic acid and 0.45 kg of sodium hydroxide, sonicate for 0.8 h, stir and react for 18 h, filter, wash the resulting filter cake with water until neutral, and vacuum dry at 60 °C to obtain carboxylated graphene oxide.

[0042] 2) Add 0.1 kg of carboxylated graphene oxide and 0.07 kg of adamantane to 1.3 kg of dimethylformamide, stir and mix evenly, then add 0.1 kg of diethyl azodicarbonate and 0.06 kg of 1-hydroxybenzotriazole, and react at 35 °C for 12 h. After the reaction is complete, remove the solvent by vacuum distillation, wash the residue three times with acetone, and dry to obtain adamantane-modified graphene.

[0043] Preparation of wastewater treatment agents based on graphene composite materials

[0044] 1.2 kg of cyclodextrin cross-linked network macromolecules and 1 kg of adamantane-modified graphene were added to 40 kg of water, dispersed evenly, heated to 45 °C, stirred for 18 h, filtered, and dried to obtain a wastewater treatment agent based on graphene composite material.

[0045] Example 4: Preparation of cyclodextrin cross-linked network macromolecules

[0046] 0.1 kg of octa(6-bromo-6-deoxy)-γ-cyclodextrin and 0.045 kg of 2-aminohydroquinone were added to 0.9 kg of dimethyl sulfoxide and stirred until homogeneous. Then, 0.075 kg of potassium carbonate was added, and the mixture was heated to 90 °C for 6 h. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed three times with a 1:1 mixture of ethanol and water and dried to obtain a cyclodextrin cross-linked network macromolecule.

[0047] Preparation of adamantane-modified graphene

[0048] 1) Add 0.1 kg of graphite oxide to 28 kg of water, sonicate for 0.9 h, then add 0.9 kg of chloroacetic acid and 0.55 kg of sodium hydroxide, sonicate for 0.9 h, stir and react for 22 h, filter, wash the resulting filter cake with water until neutral, and vacuum dry at 60 °C to obtain carboxylated graphene oxide.

[0049] 2) Add 0.1 kg of carboxylated graphene oxide and 0.09 kg of adamantane to 1.4 kg of dimethyl sulfoxide, stir and mix evenly, then add 0.13 kg of diethyl azodicarbonate and 0.07 kg of 1-hydroxybenzotriazole, and react at 38 °C for 10 h. After the reaction is complete, remove the solvent by vacuum distillation, wash the residue three times with acetone, and dry to obtain adamantane-modified graphene.

[0050] Preparation of wastewater treatment agents based on graphene composite materials

[0051] 1.4 kg of cyclodextrin cross-linked network macromolecules and 1 kg of adamantane-modified graphene were added to 45 kg of water, dispersed evenly, heated to 48 °C, stirred for 20 h, filtered, and dried to obtain a wastewater treatment agent based on graphene composite material.

[0052] Example 5: Preparation of cyclodextrin cross-linked network macromolecules

[0053] 0.1 kg of octa(6-bromo-6-deoxy)-γ-cyclodextrin and 0.05 kg of 2-aminohydroquinone were added to 1 kg of dimethyl sulfoxide and stirred until homogeneous. Then, 0.08 kg of potassium hydroxide was added and the mixture was heated to 100 °C for 5 h. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed three times with a 1:1 mixture of ethanol and water and dried to obtain a cyclodextrin cross-linked network macromolecule.

[0054] Preparation of adamantane-modified graphene

[0055] 1) Add 0.1 kg of graphene oxide to 30 kg of water, sonicate for 1 h, then add 1 kg of chloroacetic acid and 0.6 kg of sodium hydroxide, sonicate for 1 h, stir and react for 24 h, filter, wash the resulting filter cake with water until neutral, and vacuum dry at 60 °C to obtain carboxylated graphene oxide.

[0056] 2) Add 0.1 kg of carboxylated graphene oxide and 0.1 kg of adamantane to 1.5 kg of dimethyl sulfoxide, stir and mix evenly, then add 0.15 kg of diethyl azodicarbonate and 0.08 kg of 1-hydroxybenzotriazole, and react at 40 °C for 8 h. After the reaction is complete, remove the solvent by vacuum distillation, wash the residue three times with acetone, and dry to obtain adamantane-modified graphene.

[0057] Preparation of wastewater treatment agents based on graphene composite materials

[0058] 1.5 kg of cyclodextrin cross-linked network macromolecules and 1 kg of adamantane-modified graphene were added to 50 kg of water, dispersed evenly, heated to 50 °C, stirred for 24 h, filtered, and dried to obtain a wastewater treatment agent based on graphene composite material.

[0059] Example 6: Preparation of cyclodextrin cross-linked network macromolecules

[0060] 0.1 kg of octa(6-bromo-6-deoxy)-γ-cyclodextrin and 0.04 kg of 2-aminohydroquinone were added to 0.7 kg of dimethylformamide and stirred until homogeneous. Then, 0.08 kg of sodium hydroxide was added, and the mixture was heated to 100 °C and reacted for 10 h. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed three times with a 1:1 mixture of ethanol and water and dried to obtain cyclodextrin cross-linked network macromolecules.

[0061] Preparation of adamantane-modified graphene

[0062] 1) Add 0.1 kg of graphene oxide to 25 kg of water and sonicate for 1 h. Then add 0.7 kg of chloroacetic acid and 0.6 kg of sodium hydroxide and sonicate for 1 h. Stir and react for 24 h. Filter the mixture and wash the resulting filter cake with water until neutral. Dry it under vacuum at 60 °C to obtain carboxylated graphene oxide.

[0063] 2) Add 0.1 kg of carboxylated graphene oxide and 0.8 kg of adamantane to 1.5 kg of dimethyl sulfoxide, stir and mix evenly, then add 0.15 kg of diethyl azodicarbonate and 0.03 kg of 1-hydroxybenzotriazole, and react at 40 °C for 15 h. After the reaction is complete, remove the solvent by vacuum distillation, wash the residue three times with acetone, and dry to obtain adamantane-modified graphene.

[0064] Preparation of wastewater treatment agents based on graphene composite materials

[0065] 1.2 kg of cyclodextrin cross-linked network macromolecules and 1 kg of adamantane-modified graphene were added to 50 kg of water, dispersed evenly, heated to 40 °C, stirred for 24 h, filtered, and dried to obtain a wastewater treatment agent based on graphene composite material.

[0066] Comparative Example 1: Preparation of Wastewater Treatment Agent Based on Graphene Composite Material

[0067] 1.2 kg of cyclodextrin cross-linked network macromolecules and 1 kg of graphene were added to 40 kg of water, dispersed evenly, heated to 45°C, stirred for 18 h, filtered, and dried to obtain a wastewater treatment agent based on graphene composite materials. The preparation method of the cyclodextrin cross-linked network macromolecules was the same as in Example 3.

[0068] The wastewater treatment agents based on graphene composite materials prepared in Examples 1-6 and Comparative Example 1 were added to water (the mass ratio of treatment agent to water was 1:30), stirred evenly, and allowed to stand to observe sedimentation. Samples were also taken and observed under a microscope for the presence of large agglomerated particles. Comparative Example 2 used commercially available graphene. The test results are shown in Table 1. As can be seen from the results in Table 1, the wastewater treatment agent based on graphene composite materials prepared in this invention exhibits higher dispersibility and stability due to the host-guest complexation between cyclodextrin and adamantane, which inhibits the agglomeration of graphene in water.

[0069] Table 1. Dispersion results of materials prepared in Examples 1-6 and Comparative Examples 1-2

[0070]

[0071]

[0072] 20 mg of the wastewater treatment agent based on graphene composite material prepared in Examples 1-6 and Comparative Example 1 of this invention were placed in 100 ml of Pb(NO3)2 solution with a concentration of 100 mg / ml. The pH of the solution was adjusted to 6, and the mixture was stirred at 150 rpm for 2 h. After filtration, the concentration of lead ions in the filtrate was determined using an atomic absorption spectrometer, and the adsorption capacity was calculated. The formula for calculating the adsorption capacity is as follows:

[0073]

[0074] Where Q is the adsorption capacity, in mg / g; C0 is the initial concentration of lead ions, in mg / ml; C e V represents the equilibrium concentration of lead ions in mg / ml, V represents the initial total volume of the solution in ml, and m represents the mass of the adsorbent in g.

[0075] Comparative Example 2 uses commercially available graphene, and its test results are shown in Table 2. As can be seen from the results in Table 2, the wastewater treatment agent based on graphene composite material prepared in this invention has stronger adsorption capacity, larger loading capacity, and a higher adsorption rate for heavy metal ions compared to the comparative example.

[0076] Table 2 Adsorption capacity results of materials

[0077]

[0078]

[0079] The wastewater treatment agents based on graphene composite materials prepared in Examples 1-6 of this invention were used to treat industrial wastewater containing heavy metals. The volume-to-mass ratio of industrial wastewater to treatment agent was 1L:0.5g, and the treatment time was 5h. The test results are shown in Table 3.

[0080] Table 3 shows the treatment results of industrial wastewater using the materials prepared in the examples.

[0081] Group <![CDATA[Cu 2+ (mg / L)]]> <![CDATA[Ni 2+ (mg / L)]]> <![CDATA[Zn 2+ (mg / L)]]> Before processing 452.4 220.7 96.8 Example 1 0.24 0.21 0.41 Example 2 0.20 0.16 0.35 Example 3 0.19 0.11 0.30 Example 4 0.20 0.14 0.32 Example 5 0.23 0.22 0.38 Example 6 0.22 0.19 0.37

[0082] As can be seen from the results in Table 3, the wastewater treatment agent based on graphene composite material prepared in this invention can be used to adsorb heavy metal ions in wastewater, and the treated industrial wastewater can meet the requirements for heavy metal wastewater treatment in GB 8978-1996 "Integrated Wastewater Discharge Standard".

[0083] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Based on the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A wastewater treatment agent based on graphene composite materials, characterized in that: It consists of 1-1.5 parts by weight of cyclodextrin cross-linked network macromolecules and 1 part of adamantane-modified graphene; The cyclodextrin cross-linked network macromolecules were prepared according to the following method: Octa(6-bromo-6-deoxy)-γ-cyclodextrin and 2-aminohydroquinone were added to an organic solvent and stirred until homogeneous. Then, an inorganic basic compound was added and the mixture was heated to 50-100°C for 5-10 hours. After the reaction was completed, the mixture was filtered, and the solvent was removed by vacuum distillation of the filtrate. The filtrate was washed 2-3 times with a mixed solvent of ethanol and water in a volume ratio of 1:1 and dried to obtain cyclodextrin cross-linked network macromolecules. The preparation method of the adamantane-modified graphene includes the following steps: 1) Add graphene oxide to water and sonicate for 0.5-1 h. Then add chloroacetic acid and sodium hydroxide and sonicate for 0.5-1 h. Stir and react for 12-24 h. Filter the mixture and wash the resulting filter cake with water until neutral. Dry it under vacuum at 60 °C to obtain carboxylated graphene oxide. 2) Add the carboxylated graphene oxide and adamantane obtained in step 1) to an organic solvent, stir and mix evenly, then add diethyl azodicarbonate and 1-hydroxybenzotriazole, and react at 25~40℃ for 8~15h. After the reaction is completed, remove the solvent by vacuum distillation, wash the residue with acetone 2~3 times, and dry to obtain adamantane modified graphene.

2. The wastewater treatment agent based on graphene composite material as described in claim 1, characterized in that: The organic solvent is dimethyl sulfoxide or dimethylformamide.

3. The wastewater treatment agent based on graphene composite material as described in claim 1, characterized in that: The inorganic alkaline compound is potassium carbonate, sodium carbonate, potassium hydroxide, or sodium hydroxide.

4. The wastewater treatment agent based on graphene composite material as described in claim 1, characterized in that: The mass ratio of the octa(6-bromo-6-deoxy)-γ-cyclodextrin, 2-aminohydroquinone, organic solvent, and inorganic basic compound is 1:0.3~0.5:5~10:0.6~0.

8.

5. The wastewater treatment agent based on graphene composite material as described in claim 1, characterized in that: The mass ratio of graphite oxide, water, chloroacetic acid, and sodium hydroxide in step 1) is 1:200~300:5~10:3~6.

6. The wastewater treatment agent based on graphene composite material as described in claim 1, characterized in that: In step 2), the mass ratio of carboxylated graphene oxide, adamantane, organic solvent, diethyl azodicarbonate, and 1-hydroxybenzotriazole is 1:0.3~1:10~15:0.5~1.5:0.3~0.

8.

7. The method for preparing the wastewater treatment agent based on graphene composite material according to claim 1, characterized in that: By weight, 1-1.5 parts of cyclodextrin cross-linked network macromolecules and 1 part of adamantane-modified graphene are added to 30-50 parts of water, dispersed evenly, heated to 40-50℃, stirred for 12-24 hours, filtered, and dried to obtain a wastewater treatment agent based on graphene composite material.

8. The application of the wastewater treatment agent based on graphene composite material as described in claim 1 in the adsorption of heavy metal ions in wastewater.

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