Preparation method of flexible carbon / MoS2 heterojunction adsorption material and application of flexible carbon / MoS2 heterojunction adsorption material as adsorbent

Abstract

The invention belongs to the technical field of environmental pollution control, and particularly relates to a preparation method of a flexible carbon / MoS2 heterojunction adsorption material and application of the flexible carbon / MoS2 heterojunction adsorption material as an adsorbent. The preparation method comprises the following steps: S1, cleaning waste cellulose fibers with deionized water and ethanol, drying, heating to 700-900 DEG C for carbonization in an inert atmosphere, and preserving heat for 1-3 hours to obtain a flexible carbon skeleton substrate with a complete structure; s2, carrying out oxidation treatment on the carbon skeleton substrate in an air atmosphere at 200-400 DEG C for 0.5-2 hours; s3, a molybdenum source and a sulfur source are dissolved in deionized water according to the molar ratio of Mo to S being 1: 2-1: 20; immersing the oxidized carbon skeleton substrate into the precursor solution, putting into a reaction kettle, and carrying out hydrothermal reaction at 140-200 DEG C for 6-18 hours; and washing the product, and carrying out vacuum drying. The flexible heterojunction material prepared by the method has macroscopic flexibility, super-hydrophilicity and abundant high-activity sites, and can be directly used as a self-supporting adsorption film; the defects that a traditional powder adsorbent is difficult to separate and easy to lose are overcome.

Description

Technical Field

[0001] This invention belongs to the field of environmental pollution control technology, specifically relating to a method for preparing a flexible carbon / MoS2 heterojunction adsorbent and its application as an adsorbent. Background Technology

[0002] Faced with the growing challenge of environmental pollution worldwide, developing efficient and feasible environmental remediation technologies has become a strategic necessity. In the treatment of dyeing and printing wastewater, developing adsorbent materials that are easy to separate and recover and can adapt to complex fluid environments is crucial.

[0003] Adsorption is widely used to remove dye pollutants (such as methylene blue) from water bodies due to its simplicity and relatively low cost. However, existing adsorption materials face significant bottlenecks in terms of material morphology, operability, and performance synergy: 1) The triple contradiction between performance, cost, and operability of traditional adsorbents: While powdered adsorbents such as activated carbon and biomass carbon are low-cost, they are difficult to separate from water after adsorption, easily causing secondary pollution and difficult recycling. High-performance adsorbents such as carbon nanotubes and graphene are limited to large-scale engineering applications due to their high cost and the same solid-liquid separation challenges. 2) Structural stability and morphological defects of novel adsorbents: Nanomaterials such as molybdenum disulfide (MoS2) have good affinity for dye molecules, but MoS2 prepared by conventional methods is mainly composed of a 2H semiconductor phase with surface inertness and poor hydrophilicity, which is prone to stacking, resulting in insufficient adsorption sites and low contact efficiency. Although highly active 1T metallic phase MoS2 can be obtained through chemical exfoliation, it is mostly composed of unstable dispersed nanosheets, making macroscopic shaping and recycling difficult. Even when nanomaterials are loaded onto traditional carriers, the resulting composite powders still cannot escape the constraints of relying on filter membranes or complex molding processes. 3) Disconnect between material morphology design and application scenarios: Most studies focus on improving the adsorption capacity of powder materials, but neglect the requirements for the macroscopic morphology and ease of handling of materials in actual water treatment processes (such as dynamic filtration and continuous operation). There is a lack of a material that integrates high adsorption activity, stable structure, inherent flexibility, and renewability, and can be directly used as an easily separable adsorption element.

[0004] Therefore, breaking through the design barriers between the microscopic activity and macroscopic morphology of existing materials and developing an adsorption material that combines high active sites (such as being rich in 1T phase), excellent hydrophilicity, inherent flexibility, and a stable integrated structure is the key to solving the dual challenges of "adsorption efficiency" and "separation operability" in dye wastewater treatment. Summary of the Invention

[0005] In response to the current comprehensive requirements of the environmental remediation field for adsorbent materials in terms of high performance, easy recycling, low cost and high stability, this invention aims to overcome the technical bottlenecks such as the difficulty in separating traditional powder adsorbents, the difficulty in macroscopic shaping of novel nanomaterials, and the instability of existing composite material interfaces. It provides an integrated flexible adsorbent material that can be easily separated directly from wastewater and integrates high adsorption performance, intrinsic flexibility, superhydrophilicity and good regenerability, as well as its controllable preparation method.

[0006] To achieve the above objectives, the present invention provides an integrated flexible carbon / MoS2 heteroadsorbent material based on regenerated cellulose fiber, its preparation method, and its application.

[0007] The preparation method described in this invention uses regenerated cellulose fiber fabrics (such as viscose spunlace nonwoven fabric) as raw materials. Through a precisely controllable "carbonization-oxidation-hydrothermal synthesis" process, an integrated self-supporting flexible heterojunction structure is constructed and used in flexible composite materials for dye adsorbents. The core innovation of this method lies in the successful preparation of a self-supporting thin film material with both macroscopic flexibility and superhydrophilicity by controlling three key process variables: carbonization temperature, oxidation temperature, and hydrothermal temperature. The proportion of the 1T metal phase in the MoS2 active component is as high as over 70%, providing abundant active sites. A three-step controllable process of "carbonization-oxidation-hydrothermal synthesis" has been developed. The material fully inherits the three-dimensional fiber network of the precursor, realizing an "intrinsically integrated" flexible carbon / MoS2 heterojunction material that combines a flexible framework, active material, and self-supporting structure. This allows for the efficient acquisition of functional adsorbent materials with high adsorption performance from waste raw materials.

[0008] A method for preparing an integrated flexible carbon / / MoS2 heterojunction material based on regenerated cellulose fibers includes the following steps:

[0009] Preparation of S1 flexible carbon framework

[0010] Using spunlace nonwoven fabric made from regenerated cellulose fibers (preferably viscose fiber, in the form of commercially available face towel substrate) as raw material, the material is cleaned with deionized water and ethanol, dried, and then carbonized under an inert atmosphere to obtain a monolithic carbon skeleton that combines macroscopic flexibility and hydrophobicity. This step inherits the three-dimensional fiber network of the precursor, providing the material with a self-supporting and flexible carbon skeleton.

[0011] S2 oxidation

[0012] The carbon skeleton is gently oxidized in air to introduce abundant oxygen-containing functional groups onto its surface. These functional groups can serve as active anchoring sites for subsequent hydrothermal growth and significantly improve the superhydrophilicity of the material surface.

[0013] In-situ hydrothermal synthesis of S3 1T / 2H-MoS2 heterojunction: Using an oxidized carbon skeleton as a carrier, molybdenum and sulfur sources react under hydrothermal conditions. By precisely controlling key process variables such as carbonization temperature, oxidation temperature, and hydrothermal temperature, molybdenum disulfide (MoS2) nanosheets rich in highly active 1T metallic phase are grown in situ on the carbon skeleton, ultimately forming a structurally robust carbon / MoS2 heterojunction material. The process includes the following steps:

[0014] 1) Preparation of precursor solution: Dissolve molybdenum source and sulfur source in deionized water at a Mo:S molar ratio of 1:2 to 1:20;

[0015] 2) Hydrothermal reaction: The oxidized carbon skeleton is immersed in the precursor solution, placed in a reaction vessel, and subjected to hydrothermal reaction at 140-200 °C for 6-18 hours;

[0016] 3) Post-processing: The product is washed and then vacuum dried.

[0017] In the above scheme, in step S1, the waste regenerated cellulose fiber fabric is selected as viscose spunlace nonwoven fabric (such as waste disposable face towels). Carbonization is carried out under an inert atmosphere, with the temperature programmed to rise to 700-900 ℃ at a rate of 2-5 ℃ / min, and held at that temperature for 1-3 hours. The inert atmosphere can be nitrogen or argon.

[0018] In step S2, the oxidation treatment is carried out at 200-400 ℃ for 0.5-2 hours, with the preferred oxidation temperature being 350 ℃.

[0019] Preferably, in step S3, the molybdenum source is ammonium molybdate or sodium molybdate, and the sulfur source is thiourea or thioacetamide. The vacuum drying temperature can be selected as 60-80 °C.

[0020] The integrated flexible carbon / MoS2 heterojunction material prepared in this invention can be directly used as a highly efficient and recyclable self-supporting adsorption membrane. With its superhydrophilicity, three-dimensional open pores, and abundant highly active sites, this material can efficiently adsorb organic dye pollutants (such as methylene blue) in water. Its ultra-high adsorption capacity, rapid adsorption kinetics, and good recyclability, combined with the inherent morphology of the macroscopic flexible membrane, make the solid-liquid separation operation after adsorption extremely simple—simply remove the entire material from the solution physically, completely solving the engineering problems of difficult separation and easy loss of traditional powder adsorbents. Furthermore, the preparation method does not rely on any surfactants or template agents throughout the process, making the process green and simple. The resulting material is easy to recycle after use and has the potential for further resource utilization.

[0021] The regenerated cellulose fiber fabrics described in this invention include, but are not limited to, nonwoven fabrics made from viscose fibers, lyocell fibers, etc., through processes such as spunlace and bonding. For ease of explanation, the following examples will be described in detail using common viscose fiber spunlace nonwoven fabric (e.g., commercially available disposable face towels) waste as an example. Attached Figure Description

[0022] Figure 1 These are photographs showing the hydrophilicity and macroscopic morphology of the integrated flexible carbon / MoS2 heterojunction material after carbonization, before and after carbon oxidation, and in Example 1 of this invention.

[0023] Figure 2 This is a photograph showing the flexibility of the integrated flexible carbon / MoS2 heterojunction material in Embodiment 1 of the present invention.

[0024] Figure 3 The images shown are SEM images and magnified SEM images of the integrated flexible carbon / MoS2 heterojunction material after carbon oxidation in Example 1 of this invention.

[0025] Figure 4 The image shows the Raman spectrum of the integrated flexible carbon / MoS2 heterojunction material in Example 1 of this invention.

[0026] Figure 5 This is a high-resolution XPS image of the integrated flexible carbon / MoS2 heterojunction material in Example 1 of the present invention.

[0027] Figure 6 The cyclic adsorption performance of methylene blue by the integrated flexible carbon / MoS2 heterojunction material in Example 1 of this invention is shown. Detailed Implementation

[0028] The specific conditions for preparing the integrated flexible superhydrophilic carbon / MoS2 heterojunction material of the present invention are as follows:

[0029] (1) Raw materials

[0030] Main raw material: Spunlace nonwoven fabric of regenerated cellulose fibers of a certain size, preferably viscose fibers, which can be used as the main substrate for commercially available disposable face towels and other products. Its natural three-dimensional interwoven network is an ideal precursor for forming the macroscopic flexible structure of the final material.

[0031] Chemical raw materials: molybdenum source (such as ammonium molybdate, sodium molybdate) and sulfur source (such as thiourea, thioacetamide) are all commercially available analytical grade reagents.

[0032] (2) Steps and conditions:

[0033] The entire process is divided into three stages, with the second and third stages being the key control points that determine the final function and performance of the material.

[0034] Preparation of S1 flexible conductive carbon framework

[0035] Pretreatment: Wash the waste viscose fiber spunlace nonwoven fabric (such as commercially available disposable face towels) with deionized water and ethanol, and then dry it.

[0036] Carbonization: Under an inert atmosphere (N2 or Ar), the temperature is increased to 700-900°C at a rate of 2-5°C / min and held for 1-3 hours to obtain a flexible conductive carbon fiber network.

[0037] S2 oxidation

[0038] The carbon skeleton is oxidized in air at 200-400°C (preferably 350°C) for 0.5-2 hours (preferably 2 hours). This step introduces a large number of oxygen-containing functional groups into the carbon surface, changing it from hydrophobic to superhydrophilic (water contact angle ≈ 0°), and creating conditions for the formation of strong interfacial Mo-OC bonds.

[0039] In-situ hydrothermal synthesis of S3 1T / 2H-MoS2 heterojunction

[0040] 1) Preparation of precursor solution: Dissolve molybdenum source and sulfur source in deionized water at a Mo:S molar ratio of 1:2 to 1:20.

[0041] 2) Hydrothermal reaction: The carbon skeleton after splitting is immersed in the precursor solution and placed in a reactor for hydrothermal reaction. A relatively low temperature is used, reacting at 140-200 ℃ for 12 hours. The lower temperature is conducive to the formation of nanosheets with more defects and a larger specific surface area, while protecting the oxygen-containing functional groups introduced by the oxidation treatment from excessive damage.

[0042] 3) Post-processing: After washing, the product is dried under vacuum at 60 °C.

[0043] (3) Application of the flexible material

[0044] This material can be directly used as a highly efficient and recyclable adsorbent. Due to its superhydrophilicity, open pores, and abundant active sites, it can be directly immersed in organic dye solutions for adsorption testing, efficiently adsorbing organic dyes (such as methylene blue) from water. The preparation method does not involve the use of any additional surfactants or template agents. After use, it can be easily removed from the water and recovered through physical means, or further utilized as a resource, solving processing and separation challenges.

[0045] The properties of the materials prepared by the above method are determined by the following methods:

[0046] Structural characterization: SEM showed that the MoS2 nanosheets prepared at a lower hydrothermal temperature (140 °C) were thinner and more extended, avoiding the surface-to-surface stacking problem of traditional MoS2 nanosheets.

[0047] Adsorption performance test: The concentration of methylene blue (MB) in the solution before and after adsorption was determined by spectrophotometry according to GB / T 12496.10-1999 "Test Methods for Wood-based Activated Carbon: Determination of Methylene Blue Adsorption Value", and the adsorption capacity q was calculated according to the following formula (1).

[0048]

[0049] In the formula, C0 and Ce are the initial concentration and adsorption equilibrium concentration of the methylene blue solution, respectively, and V and m are the volume of the methyl orange solution and the mass of the adsorbent, respectively.

[0050] Example 1

[0051] Waste viscose fiber spunlace nonwoven fabric (disposable face towels were used in this embodiment) was cut to an appropriate size, ultrasonically cleaned with deionized water and ethanol respectively, and then dried. It was then placed in a tube furnace and heated to 750 °C at a rate of 5 °C / min under a nitrogen atmosphere, held for 3 hours, and allowed to cool naturally to room temperature. Afterward, it was transferred to a muffle furnace and treated at 350 °C for 2 hours to obtain a superhydrophilic flexible carbon framework. A 32 mL aqueous solution containing 0.77 g of ammonium molybdate tetrahydrate and 0.67 g of thiourea was prepared, magnetically stirred until completely dissolved, and then transferred to a 50 mL polytetrafluoroethylene liner. The flexible carbon framework was placed in the precursor solution, fully impregnated, and the vessel was sealed and placed in a forced-air drying oven. The temperature was raised to 140 °C and held for 12 hours, then allowed to cool naturally to room temperature. The black flexible product obtained from the reaction was taken out, washed with deionized water and ethanol respectively, and then dried in a vacuum drying oven at 80℃ for 12 h to obtain an integrated flexible superhydrophilic carbon / MoS2 heterojunction material.

[0052] Testing revealed that the flexible carbon framework obtained in this embodiment was hydrophobic before oxidation, while both the oxidized carbon framework and the flexible carbon / MoS2 heterojunction material were superhydrophilic after oxidation. Figure 1 As shown.

[0053] Testing showed that the composite material obtained in this embodiment could still be repeatedly bent without any damage after being pressed with a 100 g weight, and could also be repeatedly bent 180°, demonstrating its robustness as a flexible membrane material. Figure 2 As shown.

[0054] Upon inspection, the flexible carbon framework obtained in this embodiment exhibits a fibrous structure, and the flexible carbon / MoS2 heterojunction material is a hierarchical structure material. Nanosheets are uniformly and interwoven across the carbon fiber framework, avoiding stacking. Figure 3 As shown.

[0055] Testing revealed that the main component of the material obtained in this embodiment is a carbon composite material supported on 1T / 2H-MoS2, with the 1T phase accounting for up to 70%. The interface between 1T / 2H-MoS2 and carbon fiber is stabilized through Mo-OC bonds. Figure 4 and Figure 5 As shown.

[0056] The integrated flexible carbon / MoS2 heterojunction material obtained in this embodiment was directly used as an adsorbent, and its adsorption performance was tested. The experimental conditions were as follows: the adsorbent mass was 2±1 mg, the adsorption temperature was 5-50 ℃, the organic dye used was methylene blue (MB), the initial solution concentration was 5-30 mg / L, the pH was 3-11, the volume was 50 mL, and the static adsorption was carried out for 3 h.

[0057] In Example 1, the following test results are all the lowest values ​​of existing statistical data.

[0058] Using this example as the adsorbent, it was added to a 20 mg / L MB solution (pH=7) and adsorbed for 3 hours at temperatures of 5, 10, 20, 30, 40, and 50 °C. The results showed that the adsorption capacity was highest at 40 °C, reaching 363 mg / g.

[0059] Using this example as the adsorbent, 50 mL of MB solutions (pH=7) with different initial concentrations (5-30 mg / L) were added, and adsorption was carried out at 25°C for 3 hours. As the MB concentration increased from 5 to 25 mg·L⁻¹, the adsorption capacity increased from 170 to 310 mg / g, reaching its maximum at a concentration of 25 mg / L.

[0060] Using this example as the adsorbent, it was added to 50 mL of 20 mg / L MB solution, and adsorbed for 3 hours at pH 3, 5, 7, 9, and 11 at 25°C. The results showed that the adsorption capacity was higher under neutral and alkaline conditions, reaching 312 mg·g⁻¹ at pH=7, while it was only 71 mg·g⁻¹ under acidic conditions (pH=3).

[0061] Using this example as the adsorbent, the adsorption temperature was 40 °C, the organic dye used was methylene blue (MB), the initial solution concentration was 25 mg / L, the pH was 7, and the volume was 50 mL. After static adsorption for 3 h, the maximum adsorption capacity for methylene blue was 373 mg / g. After 5 adsorption-desorption cycles, the adsorbent still maintained 76% of its initial adsorption capacity. Figure 6 As shown. Its macroscopic fibrous structure makes it easy to remove from the reactor, and it can still be repeatedly bent without any damage after adsorbing dye (e.g. Figure 4 As shown in the figure, this completely avoids the cumbersome steps and secondary pollution risks of centrifugal separation of powdered adsorbents.

[0062] When the organic dye was changed to Rhodamine B (RhB), the initial concentration was 25 mg / L, the pH was 7, the volume was 50 mL, and the adsorption capacity was 310 mg / g after static adsorption for 3 h.

[0063] When the organic dye was changed to methyl orange (MB), the initial concentration was 25 mg / L, the pH was 7, the volume was 50 mL, and the adsorption capacity was 105 mg / g after static adsorption for 3 h.

[0064] Example 2

[0065] The steps of Example 1 were repeated, except that the hydrothermal reaction temperature was 200 °C. After washing and drying, the resulting product yielded an integrated flexible superhydrophilic carbon / MoS2 heterojunction material. This material was used as an adsorbent at an adsorption temperature of 40 °C. The organic dye used was methylene blue (MB), with an initial solution concentration of 25 mg / L, a pH of 7, and a volume of 50 mL. After static adsorption for 3 hours, the results showed that the adsorption capacity of this example was 306 mg / g.

[0066] Example 3

[0067] The steps of Example 1 were repeated, except that the hydrothermal reaction temperature was 180 °C. After washing and drying, the resulting product yielded a flexible carbon / MoS2 heterojunction material derived from waste face towels. This material was used as an adsorbent at an adsorption temperature of 40 °C. The organic dye used was methylene blue (MB), with an initial solution concentration of 25 mg / L, a pH of 7, and a volume of 50 mL. After static adsorption for 3 h, the results showed that the adsorption capacity of this example was 314 mg / g.

[0068] Example 4

[0069] The steps of Example 1 were repeated, except that the carbonized washcloth was not oxidized, and the precursor solution was replaced with an aqueous solution of 3 mg / mL ammonium molybdate tetrahydrate, 25 mg / mL thiourea, and 0.1 mg / mL ascorbic acid. The hydrothermal reaction temperature was 200 °C. After washing and drying, the resulting product yielded a flexible carbon / MoS2 heterojunction material derived from the waste washcloth. This material was used as an adsorbent at an adsorption temperature of 40 °C. The organic dye used was methylene blue (MB), with an initial solution concentration of 25 mg / L, pH 7, and a volume of 50 mL. After static adsorption for 3 h, the results showed that the adsorption capacity of this example was 333 mg / g.

[0070] Example 5

[0071] The steps of Example 1 were repeated, except that the carbonized washcloth was not oxidized, the hydrothermal reaction temperature was 200 °C, ammonium molybdate tetrahydrate in the precursor solution was replaced with sodium molybdate, thiourea was replaced with thioacetamide, the Mo:S molar ratio was changed to 1:5, and 0.1 mg / mL ascorbic acid was added to obtain a flexible carbon / MoS2 heterojunction material derived from waste washcloths. This material was used as an adsorbent at an adsorption temperature of 40 °C. The organic dye used was methylene blue (MB), with an initial solution concentration of 25 mg / L, pH 7, and a volume of 50 mL. After static adsorption for 3 h, the results showed that the adsorption capacity of this example was 266 mg / g.

[0072] Comparative Example 1

[0073] Compared with Example 1, except for the absence of a hydrothermal process, the experimental conditions were the same as in Example 1. That is, only the carbonized face towel that was first carbonized and then treated in a muffle furnace was used, and the flexible superhydrophilic carbonized face towel obtained in this comparative example was directly used as an adsorbent.

[0074] The adsorption performance of the carbonized face towel obtained in this comparative example was tested. It was used as an adsorbent, the adsorption temperature was 25 ℃, the organic dye used was methylene blue (MB), the initial solution concentration was 20 mg / L, the pH was 7, the volume was 50 mL, and after static adsorption for 3 h, the adsorption capacity of the carbonized face towel for MB was calculated to be 175 mg / g.

[0075] Comparative Example 2

[0076] Compared to Example 1, except that the flexible carbon framework was not added during the hydrothermal process, the hydrothermal conditions were the same as in Example 1. That is, only the same concentration and volume of ammonium molybdate tetrahydrate and thiourea solution were used, and the hydrothermal reaction was carried out at 140 °C for 12 hours. The reaction product was collected by centrifugation, washed, and dried to obtain MoS2 powder.

[0077] The MoS2 powder obtained in this comparative example was used as an adsorbent. The adsorption temperature was 25 °C, and the organic dye used was methylene blue (MB). The initial solution concentration was 20 mg / L, the pH was 7, and the volume was 50 mL. After static adsorption for 3 h, the results showed that the adsorption capacity of the MoS2 powder obtained in this comparative example for methylene blue was 161 mg / g.

[0078] Comparative Example 3

[0079] Compared to Example 1, the difference lies in replacing the regenerated cellulose fiber washcloth with natural cellulose fiber cotton cloth, and the hydrothermal treatment is not performed. The resulting carbonized cotton cloth is used directly as an adsorbent at an adsorption temperature of 40 °C. The organic dye used is methylene blue (MB), with an initial solution concentration of 25 mg / L, pH 7, and a volume of 50 mL. After static adsorption for 3 h, the results show that the adsorption capacity of the carbonized cotton cloth obtained in this comparative example for methylene blue is 88 mg / g.

[0080] Comparative Example 4

[0081] Compared to Example 1, the difference lies in replacing the regenerated cellulose fiber washcloth with natural cellulose fiber cotton cloth to prepare an integrated carbon / MoS2 heterojunction material derived from waste cotton cloth. This material was used as an adsorbent at an adsorption temperature of 40°C. The organic dye used was methylene blue (MB), with an initial solution concentration of 25 mg / L, pH 7, and a volume of 50 mL. After static adsorption for 3 h, the results showed an adsorption capacity of 187 mg / g for a 25 mg / L MB solution and 299 mg / g for a 50 mg / L MB solution.

[0082] Testing revealed that the material obtained in this embodiment fractured after being subjected to pressure with a 100 g weight due to insufficient flexibility and structural stability, highlighting the mechanical advantages of Example 1.

[0083] Comparative Example 5

[0084] Compared to Example 1, the difference lies in replacing the regenerated cellulose fiber washcloth with natural cellulose fiber cotton cloth, and the hydrothermal reaction temperature is 200 ℃, resulting in an integrated carbon / MoS2 heterojunction material derived from waste cotton cloth. This material was used as an adsorbent at an adsorption temperature of 40 ℃, with methylene blue (MB) as the organic dye. The initial solution concentration was 25 mg / L, the pH was 7, and the volume was 50 mL. After static adsorption for 3 h, the results showed that the adsorption capacity of this example was 124 mg / g.

[0085] This invention utilizes a precisely controlled three-step process of "carbonization-oxidation-hydrothermal synthesis" to combine waste biomass conversion, microstructure (high 1T phase) control, and innovative macroscopic morphology (integrated flexible membrane) design, successfully preparing an integrated flexible carbon / MoS2 heterojunction adsorbent material suitable for practical engineering applications. The process first involves mid-temperature oxidation of the carbon framework to construct a superhydrophilic surface and introduce bonding sites; subsequently, under low-temperature hydrothermal conditions, an active MoS2 nanosheet structure with high specific surface area and multiple defects is grown; the final product fully inherits the three-dimensional fiber network of the precursor, becoming a self-supporting flexible film.

[0086] The material obtained through this process possesses macroscopic flexibility, superhydrophilicity, and a robust heterojunction interface: its superhydrophilic surface ensures instantaneous contact with pollutants; abundant defects and high specific surface area provide numerous adsorption sites; a robust interface formed through chemical bonds such as Mo-OC ensures cycling stability; and its integrated flexible film morphology enables convenient "second-level" separation. Therefore, this material exhibits high adsorption capacity, rapid adsorption kinetics, and excellent recyclability for dye pollutants, fundamentally solving the core bottleneck of traditional nano-adsorbents in engineering applications—difficulty in recovery and easy secondary pollution—and demonstrating significant innovative potential and application value in the field of environmental remediation.

Claims

1. A method for preparing a flexible carbon / MoS2 heterojunction adsorbent material, comprising the following steps: Preparation of S1 flexible carbon framework After washing and drying the regenerated cellulose fiber spunlace nonwoven fabric with deionized water and ethanol, it is heated to 700-900 ℃ and carbonized under an inert atmosphere for 1-3 hours to obtain an integrated flexible carbon skeleton. S2 oxidation The carbon skeleton of S1 was oxidized in air at 200-400 °C for 0.5-2 hours. In-situ hydrothermal synthesis of S3 1T / 2H-MoS2 heterojunction 1) Preparation of precursor solution: Dissolve molybdenum source and sulfur source in deionized water at a Mo:S molar ratio of 1:2 to 1:20; 2) Hydrothermal reaction: The oxidized carbon skeleton is immersed in the precursor solution, placed in a reaction vessel, and subjected to hydrothermal reaction at 140-200 °C for 6-18 hours; 3) Post-processing: The product is washed and then vacuum dried.

2. The preparation method according to claim 1, characterized in that, In step S1, the regenerated cellulose fiber spunlace nonwoven fabric is a viscose fiber spunlace nonwoven fabric, which contains an intertwined three-dimensional network structure formed by a high-pressure hydroentangling process.

3. The preparation method according to claim 2, characterized in that, The regenerated cellulose fiber spunlace nonwoven fabric is a commercially available disposable face towel.

4. The preparation method according to claim 1, characterized in that, In step S1, the temperature is programmed to 700-900 ℃ at a heating rate of 2-5 ℃ / min under an inert atmosphere. The inert atmosphere may be nitrogen or argon.

5. The preparation method according to claim 1, characterized in that, In step S3, the molybdenum source is ammonium molybdate or sodium molybdate, and the sulfur source is thiourea or thioacetamide.

6. The heterojunction material prepared by the method according to claims 1-5, characterized in that, The flexible superhydrophilic carbon / MoS2 heterojunction material has the characteristics of self-supporting membrane morphology, macroscopic flexibility, and superhydrophilicity, and contains 1T of MoS2 with a phase ratio of not less than 70%.

7. The heterojunction material according to claim 6, characterized in that... The MoS2 is grown in situ on a flexible carbon framework in the form of nanosheets, forming a three-dimensional porous heterojunction structure.

8. The use of the flexible carbon / MoS2 heterojunction material according to claim 6 as an adsorbent.

9. The use according to claim 8, characterized in that, The heterojunction material is used for the adsorption of dye wastewater. The heterojunction material is placed directly in the water containing dye and used as an adsorption membrane. After adsorption is completed, the material is removed as a whole to achieve solid-liquid separation.

10. In the application according to claim 9, the flexible carbon / MoS2 heterojunction material has an adsorption capacity for methylene blue of not less than 300 mg / g.

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