A method for promoting reconnection of graphene oxide after adsorbing dye by doping MXene

Abstract

The application discloses a method for promoting reconnection of graphene oxide after adsorbing dyes by doping MXene, and comprises the following steps: step one, Ti2C 3 MXene and graphene oxide (GO) are mixed in proportion, and then graphene oxide-MXene composite material is prepared by adopting a drop coating method; step two, the graphene oxide-MXene composite material obtained in step one is cut or ground and then added into a dye solution; step three, after standing for a period of time, the originally cut or ground powder of the graphene oxide-MXene composite material is reconnected together, and in the process of continuous shaking, the graphene oxide-MXene composite material can maintain stable connection and will not be broken. The application realizes recycling and reuse of the material, and avoids secondary pollution of the adsorption material to water. The method is simple in operation, and is easy to use and popularize in large scale.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, and in particular to a method for promoting the relinking of graphene oxide after adsorption of dyes by doping with MXene. Background Technology

[0002] With the acceleration of industrialization, the treatment of dye wastewater has become an important issue in the field of environmental science. Dye wastewater typically contains a large number of recalcitrant organic dye molecules, such as methylene blue (MB). These dyes are characterized by high color intensity and high toxicity, causing serious pollution to water bodies and the ecological environment. Currently, dye wastewater treatment technologies mainly include physical adsorption, chemical oxidation, and biodegradation. Among these, adsorption methods are widely used due to their advantages of high efficiency, simple operation, and low cost. Commonly used adsorption materials include activated carbon, graphene oxide (GO), and metal-organic frameworks (MOFs). These materials can effectively adsorb dye molecules through their rich pore structure and surface functional groups. However, existing adsorption materials still have some limitations in practical applications, such as slow adsorption rates, difficulty in recycling and reuse, and insufficient structural stability in complex aquatic environments.

[0003] To overcome the limitations of traditional adsorption materials, researchers have begun exploring the application of membrane materials in dye wastewater treatment. Membrane materials, by immobilizing adsorbents within a membrane matrix to form thin films with selective separation capabilities, exhibit significant advantages such as higher mechanical strength and stability, higher selectivity and permeability, ease of recovery and reuse, and simple operation. However, existing membrane materials still face limitations in adsorption rates in practical applications, primarily due to the pore structure and surface functional group distribution restricting the diffusion rate of dye molecules. To further improve the adsorption performance of membrane materials, researchers have attempted to increase the specific surface area and active sites by shearing. This treatment significantly improves the adsorption rate, enabling higher efficiency in treating complex wastewaters. However, the sheared membrane material is easily broken after adsorption, making it difficult to recover and reuse, thus limiting its operability and economic viability in practical applications. Summary of the Invention

[0004] This invention proposes a method for promoting the reconnection of MB after adsorption by graphene oxide (GO) using MXene doping. By preparing GO and MXene materials into a membrane, this invention not only improves the structural stability but also enhances the adsorption performance through the membrane's physical structure. Furthermore, this invention increases the adsorption rate of the membrane material through a shearing process and achieves reconnection and stable recovery of the membrane material after adsorption. This method not only overcomes the limitations of traditional adsorption materials but also significantly improves the adsorption efficiency and recyclability of the membrane material, reduces secondary pollution, and has significant environmental and economic implications.

[0005] The technical solution of this invention is as follows: A method for promoting the relinking of graphene oxide after dye adsorption by doping with MXene includes the following steps: Step 1: Mix Ti2C3MXene dispersion and graphene oxide solution in a certain proportion, and then prepare graphene oxide-MXene composite material by drop coating method; In step one, Ti2C3MXene and graphene oxide (GO) are mixed in different mass ratios to form a uniform composite material. This mixture is then uniformly coated onto an oil film using a drop-coating method, a simple and efficient preparation method suitable for large-scale production. The coated membrane material is placed in a forced-air drying oven for heat drying to ensure the uniformity and stability of the membrane. In the method of this invention, the mixture drop-coated onto the oil film is placed in a drying oven at 50°C for 5 hours, removed, and cooled; the composite material is easily peeled off from the base oil film. The prepared membrane material is then cut or ground to increase its specific surface area and active sites. The cut membrane material is added to a dye solution and allowed to stand, allowing the membrane material to adsorb dye molecules. The heat drying treatment is preferably carried out at 50°C for 5 hours. This condition ensures uniform drying of the membrane material while avoiding thermal damage, thus improving the mechanical strength and stability of the membrane.

[0006] Step 2 involves cutting or grinding the graphene oxide-MXene composite material prepared in Step 1 into powder (the size of the cut graphene oxide-MXene composite film should be similar to avoid uneven local performance due to excessive differences in fragment size), and then placing it into a dye solution to adsorb the dye. After standing for a period of time, once the dye adsorption is complete, the graphene oxide-MXene composite material that was originally cut or ground into powder reconnects together and remains stable and does not disperse even with continuous shaking.

[0007] Furthermore, the MXene used in step one can also be TiAlC3 doped.

[0008] Furthermore, the mass ratio of graphene oxide to Ti2C3MXene in step one is 1:9 to 9:1. Preferably, the ratio (mass ratio) of MXene to graphene oxide in step one is 1:4. Under this ratio, the adsorption efficiency of the material is greatly improved, and the reconnected structure has higher stability.

[0009] Furthermore, the dye used in step two is one of methylene blue, methyl orange, or a mixture of methylene blue and methyl orange.

[0010] Furthermore, the relinking in step two occurs in dye solutions under both acidic and weakly alkaline conditions, with better relinking under acidic conditions.

[0011] Furthermore, the reconnection in step two is performed at room temperature or below 50°C.

[0012] Furthermore, the reconnection in step two occurs in the composite material of graphene oxide and MXene.

[0013] The present invention also provides an application of the above-mentioned method for promoting the reconnection of graphene oxide after dye adsorption by doping with MXene.

[0014] The method of this invention for adsorbing dyes significantly increases the specific surface area of ​​the membrane material through shearing, resulting in a substantial increase in the adsorption rate and a reduction in adsorption time by more than 50%. This characteristic enables the membrane material of this invention to exhibit higher efficiency in treating dye wastewater. After adsorption, the sheared membrane material can reconnect and form a stable structure, facilitating recycling and reuse. This feature not only reduces material breakage and loss but also avoids secondary pollution, demonstrating significant environmental friendliness and economic feasibility. The method of this invention is simple to operate, requiring no complex equipment or high-pressure conditions. The adsorption and reconnection processes can be completed at room temperature or above. The preparation and recycling processes of the membrane material are suitable for large-scale industrial applications, showing broad application prospects. Beneficial effects

[0015] 1. Highly Efficient Adsorption and Structural Stability: This invention significantly increases the specific surface area and active sites of the membrane material by cutting it into smaller pieces, thereby greatly improving the adsorption rate of dye molecules (such as methylene blue MB) and shortening the adsorption time by more than 50%. Simultaneously, after adsorption, the cut membrane material can reconnect and form a stable structure, facilitating recycling and reuse, reducing material breakage and loss, and avoiding secondary pollution.

[0016] 2. Economic and Environmental Benefits: The method of this invention is simple to operate, requiring no complex equipment or high-temperature, high-pressure conditions. The adsorption process can be completed at room temperature, significantly reducing treatment costs. Furthermore, the membrane material can be reused multiple times through reconnection and recycling, reducing material waste. The entire process requires no chemical reagents, avoiding secondary pollution and demonstrating significant environmental friendliness and economic feasibility. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the prepared graphene oxide-MXene composite film; Figure 2 A schematic diagram of the prepared shredded graphene oxide-MXene composite film; Figure 3 A schematic diagram illustrating the reconnection of shredded graphene oxide-MXene composite films; Figure 4 This is a schematic diagram of the reconnection of graphene oxide-MXene composite films with different degrees of shearing in Example 1; Figure 5 This is a schematic diagram of the reconnection of graphene oxide-MXene composite films under different MX and GO mass ratios in Example 2; Figure 6 This is a schematic diagram of the reconnection of graphene-MXene composite films with MB solutions at different pH values ​​in Example 3; Figure 7 This is a schematic diagram of the reconnection of the graphene oxide-MXene composite film after high-temperature treatment in Example 4. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0019] Step 1: Mix Ti2C3 MXene and GO in a certain proportion, and then prepare graphene oxide-MXene composite material by drop coating method; Step 2: Cut or grind the graphene oxide-MXene composite material obtained in Step 1 and add it to the dye solution; Step 3: Let it stand for a period of time. While the dye adsorption is completed, the graphene oxide-MXene composite material that was originally cut or ground into powder is reconnected together. It can maintain a stable connection without breaking even when shaken. Example 1

[0020] A method for promoting the reconnection of MB after adsorption on graphene oxide by doping with MXene, the method comprising: Step 1: Mix Ti2C3 MXene (5 mg / ml) dispersion and GO (5 mg / ml) solution at a ratio of 1:4. Then, drop the mixture onto an oil film and dry it in a forced-air drying oven at 50°C for 5 hours to obtain a graphene oxide-MXene composite film. Figure 1 As shown; Step 2: The graphene oxide-MXene composite material obtained in Step 1 is subjected to different degrees of shearing (very fine, moderately fine, flakes), and 20 mg is added to 20 ml and 400 mg / L MB solutions respectively; Step 3: After standing for a period of time, the composite material is cut into very fine pieces (e.g., Figure 2 During dye adsorption, the previously fragmented graphene oxide-MXene composite material reconnects itself, maintaining a stable bond even under continuous shaking, without breaking. The reconnection phenomenon is as follows: Figure 3As shown, the reconnection of composite membranes after different shearing treatments is compared to, for example... Figure 4 As shown, a small degree of membrane breakage (pieces) can affect membrane reconnection. Example 2

[0021] The difference between this embodiment and Embodiment 1 is that, in step one, the Ti2C3 MXene dispersion and GO solution are uniformly mixed at different mass ratios (1:4, 3:7, 2:3, 1:1, 3:2); in step two, the graphene oxide-MXene composite material is sheared to a very fine degree; the reconnection of the films obtained at different mass ratios is as follows. Figure 5 As shown, good reconnection can occur when the quality ratio is 1:4, 3:7 or 2:3, but the reconnection effect deteriorates as the proportion of MXene increases (quality ratio 1:1 or 3:2). Example 3

[0022] The difference between this embodiment and Embodiment 1 is that in step two, the graphene oxide-MXene composite material is sheared to a very fine degree, and the MB solution environment is under different pH conditions (None, pH=2, 4, 6, 8, 10, 11). The reconnection situation under different pH solution environments is as follows: Figure 6 As shown, good reconnection can occur under acidic or neutral conditions; however, the membrane reconnection effect is very poor under alkaline conditions. Example 4

[0023] The difference between this embodiment and Embodiment 1 is that in step two, the graphene oxide-MXene composite material is heated at 200°C for 3 hours and then sheared to a very fine degree. The reconnection after heat treatment is as follows. Figure 7 As shown, it can be seen that even with poor adsorption of MB, they can still be well linked together.

Claims

1. A method for promoting the relinking of graphene oxide after dye adsorption by doping with MXene, characterized in that, Includes the following steps: Step 1: Mix Ti2C3MXene dispersion and graphene oxide solution in a certain proportion, and then prepare graphene oxide-MXene composite material by drop coating method; In step two, the graphene oxide-MXene composite material prepared in step one is cut or ground into powder and then placed into a dye solution to adsorb the dye. After standing for a period of time, the graphene oxide-MXene composite material that was originally cut or ground into powder is reconnected together and remains stable and does not disperse even when shaken continuously.

2. The method for promoting the relinking of graphene oxide after dye adsorption by doping with MXene as described in claim 1, characterized in that, The mass ratio of graphene oxide to Ti2C3MXene mentioned in step one is 1:9 to 9:

1.

3. The method for promoting relinking of graphene oxide after dye adsorption by doping with MXene as described in claim 1, characterized in that, The dye used in step two is one of methylene blue, methyl orange, or a mixture of methylene blue and methyl orange.

4. The method for promoting the relinking of graphene oxide after dye adsorption by doped MXene as described in claim 1, characterized in that, The reconnection in step two occurs under acidic or weakly alkaline conditions.

5. The method for promoting the relinking of graphene oxide after dye adsorption by doping with MXene as described in claim 1, characterized in that, The reconnection in step two is performed at a temperature below 50°C.

6. The method for promoting the relinking of graphene oxide after dye adsorption by doping with MXene as described in claim 1, characterized in that, The reconnection in step two occurs in the composite material of graphene oxide and MXene.

7. The application of the method for promoting the reconnection of dyes after adsorption by doped MXene as described in any one of claims 1-6 in the treatment of dye wastewater.

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