A molybdenum disulfide-MXene / biomass carbon composite aerogel, a preparation method and application thereof

Abstract

The application discloses a kind of molybdenum disulfide-MXene / biomass carbon composite aerogel and its preparation method and application, wherein the preparation method includes: (1) chitosan aerogel is pyrolyzed in tubular furnace at 400-800 DEG C, inert gas atmosphere;(2) the biomass carbon aerogel prepared in step (1) is soaked in ammonium molybdate tetrahydrate and thiourea mixed solution, then sodium citrate is added, and it is placed in reaction kettle and hydrothermal reaction at 160-220 DEG C;(3) MXene is added to deionized water and dispersed by ultrasonic to obtain MXene dispersion, and polydiallyldimethylammonium chloride is added to positively modify MXene, then the molybdenum disulfide / biomass carbon composite aerogel prepared in step (2) is immersed in modified MXene dispersion to obtain.The composite aerogel can exhibit high adsorption, high selectivity and high stability as an adsorption material, and has good market application prospect.

Description

Technical Field

[0001] This invention relates to the field of aerogel technology, specifically to a molybdenum disulfide-MXene / biomass carbon composite aerogel, its preparation method, and its application. Background Technology

[0002] The environmental pollution caused by the global burning of fossil fuels and the surge in energy demand have spurred the urgent development of nuclear energy. However, the unavoidable generation of radioactive waste during nuclear energy use poses a significant risk, and the resulting nuclear pollution cannot be ignored. Cesium-137 (emitting gamma rays) and Strontium-90 (emitting beta rays) are considered major sources of radioactivity and pose the highest safety risks in nuclear waste due to their long half-lives. Furthermore, most nuclear power plants are located near the coast, and leaks would severely impact the marine environment, which contains large amounts of sodium (Na₂O). + K + Ca 2+ Mg 2+ Fe 3+ Al 3+ The presence of competing ions increases the difficulty of wastewater treatment. Therefore, the efficient and selective removal and recovery of cesium and strontium ions from seawater, which has a complex and diverse composition and properties, is of great significance for the retreatment of radioactive nuclear wastewater.

[0003] Adsorption has become an effective method for removing radioactive nuclides such as cesium and strontium ions due to its advantages of low cost and convenient operation. The soft base ion S in the molybdenum disulfide structure... 2- Radioactive isotope adsorbents exhibit strong affinity and selectivity for soft acid ions such as cesium and strontium, making them a promising class of adsorbents. However, traditional adsorption methods are generally passive, resulting in low adsorption rates. Solar interfacial evaporation technology, a novel solar photothermal evaporation technique based on interfacial phase change, shows great promise for applications in seawater desalination and wastewater treatment. Biomass carbon aerogels exhibit low density, a three-dimensional porous network structure, and biodegradability, enabling efficient water transport and evaporation through capillary action, making them an excellent substrate support material for solar interfacial evaporation. MXene, a novel two-dimensional sheet material, possesses unique two-dimensional surface properties, numerous active functional groups (-O, -OH, and -F, etc.), and a high specific surface area, leading to its widespread application in adsorption and seawater desalination. Furthermore, MXene boasts a near 100% internal photothermal conversion efficiency, proving itself to be an excellent photothermal conversion material. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a molybdenum disulfide-MXene / biomass carbon composite aerogel, its preparation method, and its applications. This composite aerogel possesses excellent photothermal absorption and conversion capabilities, promotes the enrichment of radioactive cesium and strontium ions by the adsorbent material, improves its adsorption kinetic efficiency, and enables solar-powered seawater desalination. As an adsorbent material, this composite aerogel exhibits high adsorption capacity, high selectivity, and high stability, and has promising market application prospects.

[0005] The technical solution adopted is as follows:

[0006] In a first aspect, the present invention provides a method for preparing a molybdenum disulfide-MXene / biomass carbon composite aerogel, comprising the following steps:

[0007] (1) Preparation of biomass carbon aerogel: Chitosan is dispersed in acetic acid solution and stirred to dissolve to obtain chitosan dispersion. Waste leather scrap hydrolysate is added and stirred evenly. Then, glutaraldehyde crosslinking agent is added to carry out crosslinking reaction to obtain chitosan hydrogel. Chitosan aerogel is obtained by freeze drying. Then, the chitosan aerogel is pyrolyzed in a tube furnace at 400-800℃ under an inert gas atmosphere to obtain biomass carbon aerogel.

[0008] (2) Preparation of molybdenum disulfide / biomass carbon composite aerogel: The biomass carbon aerogel obtained in step (1) is soaked in a mixed solution of ammonium molybdate tetrahydrate and thiourea, and then sodium citrate is added. The aerogel is placed in a reaction vessel and hydrothermally reacted at 160-220℃ to obtain molybdenum disulfide / biomass carbon composite aerogel.

[0009] (3) Preparation of molybdenum disulfide-MXene / biomass carbon composite aerogel: First, MXene was added to deionized water and dispersed by ultrasonication to obtain MXene dispersion. Polydiallyldimethylammonium chloride was added to positively modify MXene. Then, the molybdenum disulfide / biomass carbon composite aerogel obtained in step (2) was impregnated in the modified MXene dispersion to obtain molybdenum disulfide-MXene / biomass carbon composite aerogel.

[0010] The waste leather scrap hydrolysate can be prepared using the following method, including the following steps:

[0011] First pretreatment: Weigh 25-30g of waste leather scraps from wet sheepskin blue, then add 250-300g of water, 12-15g of sulfuric acid, and 25-30g of oxalic acid. Stir in a water bath at 30-35℃ for 6-7 hours, filter and collect the product, and store it in a refrigerator.

[0012] Second pretreatment: Add 300-350g of water, 16-20g of sulfuric acid and 25-30g of oxalic acid to the product collected after the first pretreatment. Stir in a water bath at 30-35℃ for 6-7 hours. Filter and collect the product and store it in a refrigerator.

[0013] Acid hydrolysis and extraction: Add 100-150g of water and 9-12g of glacial acetic acid to the product collected after the second pretreatment. Stir in a water bath at 70-75℃ for 6-7 hours to obtain a waste leather scrap hydrolysate solution. Add sodium chloride to the waste leather scrap hydrolysate solution for salting out. Collect the waste leather scrap hydrolysate by standing and dry it for later use. Alternatively, prepare the waste leather scrap hydrolysate according to the preparation method in CN 112853746A for later use.

[0014] Furthermore, in step (1), the mass ratio of chitosan to waste leather hydrolysate is (3-10):1.

[0015] Further, in step (2), the mass ratio of ammonium molybdate tetrahydrate to thiourea is 1:(1-5); and / or, the mass ratio of biomass carbon aerogel to the sum of the masses of ammonium molybdate tetrahydrate and thiourea is 1:(30-110).

[0016] Furthermore, in step (2), the mass ratio of biomass carbon aerogel to sodium citrate is 1:(0.5-1.5).

[0017] Furthermore, the concentration of the MXene dispersion in step (3) is 0.01-3 mg / L.

[0018] Further, in step (2), the solid-liquid ratio of the mixed solution of ammonium molybdate tetrahydrate and thiourea is 1 g: (20-50) mL; and / or, in step (3), the solid-liquid ratio of molybdenum disulfide / biomass carbon composite aerogel to modified MXene dispersion is 1 g: (50-100) mL.

[0019] Further, in step (1), the chitosan aerogel is placed in a tube furnace and heated at 400-800℃ under a N2 atmosphere at 5℃·min. -1 The heating rate is pyrolysis for 2-8 hours.

[0020] Secondly, the present invention provides a molybdenum disulfide-MXene / biomass carbon composite aerogel, which is prepared by the preparation method described above.

[0021] Thirdly, the present invention provides an adsorbent comprising the molybdenum disulfide-MXene / biomass carbon composite aerogel described in the above-described scheme.

[0022] Fourthly, the application of the molybdenum disulfide-MXene / biomass carbon composite aerogel described in the above scheme in the treatment of radioactive wastewater containing cesium and strontium ions.

[0023] In the above technical solutions,

[0024] First, biomass carbon aerogel was immersed in a mixed solution of sulfur and molybdenum sources. Molybdenum disulfide was then grown in situ within the biomass carbon aerogel using a hydrothermal method to obtain a uniformly loaded molybdenum disulfide / biomass carbon composite aerogel. Sodium citrate was then added to induce vertical growth of molybdenum disulfide within the biomass carbon aerogel. Next, the molybdenum disulfide / biomass carbon composite aerogel was electrostatically assembled with MXene to obtain a molybdenum disulfide-MXene / biomass carbon composite aerogel. This composite aerogel exhibits excellent photothermal absorption and conversion capabilities, promoting the enrichment of radioactive cesium and strontium ions by the adsorbent material, improving its adsorption kinetic efficiency, and enabling solar-powered seawater desalination.

[0025] In other words, this invention controllably assembles molybdenum disulfide, MXene, and biomass carbon aerogel to construct a material that efficiently and selectively adsorbs cesium and strontium ions. It combines solar interfacial evaporation technology with adsorption methods, utilizing the photothermal effect to improve the adsorption kinetic efficiency of the adsorbent for cesium and strontium ions, while simultaneously achieving solar-powered seawater desalination.

[0026] Therefore, the beneficial effects of the present invention are as follows:

[0027] 1. This invention utilizes a hydrothermal method to grow molybdenum disulfide nanosheets in situ within biomass carbon aerogel, and adds sodium citrate to induce uniform and vertical growth of molybdenum disulfide within the biomass carbon aerogel. The biomass carbon aerogel maintains its unique three-dimensional network porous structure, which facilitates the rapid entry of cesium and strontium ions into the internal structure of the composite adsorbent. Selective adsorption of cesium and strontium ions is achieved through the active sites on the molybdenum disulfide grown within the biomass carbon aerogel.

[0028] 2. This invention achieves the controllable assembly of molybdenum disulfide / biomass carbon composite aerogel and MXene through electrostatic interaction, constructing a photothermal nanocomposite adsorbent. The local heat generated by the photothermal effect of the system can promote the adsorption of cesium ions and strontium ions by the adsorbent, improve its adsorption kinetic efficiency, realize the synergistic regulation of the system's adsorption performance and photothermal performance, and at the same time realize solar-powered seawater desalination.

[0029] 3. The materials selected in this invention are widely available and inexpensive, achieving high-value utilization of waste resources. The prepared molybdenum disulfide-MXene / biomass carbon composite aerogel does not cause secondary pollution to the environment, is easy to recycle and can be reused, making it a promising material for treating radioactive wastewater. Attached Figure Description

[0030] Figure 1The image shows the XRD pattern of the molybdenum disulfide-MXene / biomass carbon composite aerogel prepared in Example 1 of this invention.

[0031] Figure 2 This is a scanning electron microscope image of the molybdenum disulfide-MXene / biomass carbon composite aerogel prepared in Example 1 of the present invention;

[0032] Figure 3 This is a transmission electron microscope image of the molybdenum disulfide-MXene / biomass carbon composite aerogel prepared in Example 1 of the present invention.

[0033] Figure 4 The graph shows the adsorption efficiency of molybdenum disulfide-MXene / biomass carbon composite aerogel for cesium ions prepared in Example 1 of this invention.

[0034] Figure 5 This is a graph showing the adsorption efficiency of molybdenum disulfide-MXene / biomass carbon composite aerogel for strontium ions prepared in Example 1 of this invention. Detailed Implementation

[0035] The present invention will be described in detail below through specific embodiments. However, the uses and purposes of these exemplary embodiments are only for illustrating the present invention and do not constitute any limitation on the actual protection scope of the present invention, nor are they intended to limit the protection scope of the present invention to this.

[0036] Example 1

[0037] The preparation method of a molybdenum disulfide-MXene / biomass carbon composite aerogel according to this embodiment includes the following steps:

[0038] (1) Preparation of biomass carbon aerogel: 0.5 g of chitosan was dispersed in 50 mL of 0.5 mol / L acetic acid solution and stirred at 80 °C to obtain a chitosan dispersion. 0.1 g of waste leather hydrolysate was added and stirred evenly. Then, 1 mL of 5 wt% glutaraldehyde crosslinking agent was added to carry out a crosslinking reaction to obtain chitosan hydrogel. Chitosan-based aerogel was obtained by freeze-drying. Then, the chitosan-based aerogel was subjected to a vacuum furnace at 800 °C under a N2 atmosphere for 5 °C·min. -1 The biomass carbon aerogel was obtained by pyrolysis at a heating rate of 6 h.

[0039] (2) Preparation of molybdenum disulfide / biomass carbon composite aerogel: 0.03g of biomass carbon aerogel obtained in step (1) was soaked in 20mL of a mixed solution containing 0.6g of ammonium molybdate tetrahydrate and 1.6g of thiourea, and then 0.021g of sodium citrate was added. The aerogel was placed in a reaction vessel and hydrothermally reacted at 200℃ for 24h to obtain molybdenum disulfide / biomass carbon composite aerogel.

[0040] (3) Preparation of molybdenum disulfide-MXene / biomass carbon composite aerogel: First, 0.5 mg of MXene was added to 5 mL of deionized water and dispersed by ultrasonication to obtain MXene dispersion. 0.25 mg of polydiallyldimethylammonium chloride was added to positively modify MXene. Then, 0.2 g of molybdenum disulfide / biomass carbon composite aerogel obtained in step (2) was impregnated in 20 mL of modified MXene dispersion to obtain molybdenum disulfide-MXene / biomass carbon composite aerogel.

[0041] Example 2

[0042] The preparation method of a molybdenum disulfide-MXene / biomass carbon composite aerogel according to this embodiment includes the following steps:

[0043] (1) Preparation of biomass carbon aerogel: 0.5 g of chitosan was dispersed in 50 mL of 0.5 mol / L acetic acid solution and stirred at 80 °C to obtain a chitosan dispersion. 0.2 g of waste leather hydrolysate was added and stirred evenly. Then, 0.6 mL of 5 wt% glutaraldehyde crosslinking agent was added to carry out a crosslinking reaction to obtain chitosan hydrogel. Chitosan-based aerogel was obtained by freeze-drying. Then, the chitosan-based aerogel was subjected to a vacuum furnace at 600 °C and N2 atmosphere for 5 °C·min. -1 The biomass carbon aerogel was obtained by pyrolysis at a heating rate of 8 h.

[0044] (2) Preparation of molybdenum disulfide / biomass carbon composite aerogel: 0.03g of biomass carbon aerogel obtained in step (1) was soaked in 20mL of a mixed solution containing 0.6g of ammonium molybdate tetrahydrate and 0.9g of thiourea, and then 0.021g of sodium citrate was added. The mixture was placed in a reaction vessel and hydrothermally reacted at 200℃ for 24h to obtain molybdenum disulfide / biomass carbon composite aerogel.

[0045] (3) Preparation of molybdenum disulfide-MXene / biomass carbon composite aerogel: First, 0.1 mg of MXene was added to 5 mL of deionized water and dispersed by ultrasonication to obtain MXene dispersion. 0.1 mg of polydiallyldimethylammonium chloride was added to positively modify MXene. Then, 0.2 g of molybdenum disulfide / biomass carbon composite aerogel obtained in step (2) was impregnated in 20 mL of modified MXene dispersion to obtain molybdenum disulfide-MXene / biomass carbon composite aerogel.

[0046] Example 3

[0047] The preparation method of a molybdenum disulfide-MXene / biomass carbon composite aerogel according to this embodiment includes the following steps:

[0048] (1) Preparation of biomass carbon aerogel: 0.5 g of chitosan was dispersed in 50 mL of 0.5 mol / L acetic acid solution and stirred at 80 °C to obtain a chitosan dispersion. 0.3 g of waste leather hydrolysate was added and stirred evenly. Then, 1.2 mL of 5 wt% glutaraldehyde crosslinking agent was added to carry out a crosslinking reaction to obtain chitosan hydrogel. Chitosan-based aerogel was obtained by freeze-drying. Then, the chitosan-based aerogel was subjected to a nitrogen atmosphere at 800 °C for 5 °C·min in a tube furnace. -1 The biomass carbon aerogel was obtained by pyrolysis at a heating rate of 8 h.

[0049] (2) Preparation of molybdenum disulfide / biomass carbon composite aerogel: 0.03g of biomass carbon aerogel obtained in step (1) was soaked in 20mL of a mixed solution containing 0.6g of ammonium molybdate tetrahydrate and 2.6g of thiourea, and then 0.021g of sodium citrate was added. The aerogel was placed in a reaction vessel and hydrothermally reacted at 180℃ for 18h to obtain molybdenum disulfide / biomass carbon composite aerogel.

[0050] (3) Preparation of molybdenum disulfide-MXene / biomass carbon composite aerogel: First, 1 mg of MXene was added to 5 mL of deionized water and dispersed by ultrasonication to obtain MXene dispersion. 0.8 mg of polydiallyldimethylammonium chloride was added to positively modify MXene. Then, 0.2 g of molybdenum disulfide / biomass carbon composite aerogel obtained in step (2) was impregnated in 20 mL of modified MXene dispersion to obtain molybdenum disulfide-MXene / biomass carbon composite aerogel.

[0051] Experimental test:

[0052] Figure 1 The image shows the XRD pattern of the molybdenum disulfide-MXene / biomass carbon composite aerogel prepared in Example 1 of this invention. Figure 1 It can be seen that the characteristic diffraction peaks of molybdenum disulfide (002), (100), and (110) appeared in the composite aerogel, indicating that molybdenum disulfide was successfully grown in the biomass carbon aerogel. The characteristic diffraction peaks of MXene did not appear, which is because the amount of MXene introduced was small and it was uniformly dispersed in the composite aerogel.

[0053] Figure 2 This is a scanning electron microscope (SEM) image of the molybdenum disulfide-MXene / biomass carbon composite aerogel prepared in Example 1 of this invention. As can be seen from the image, the composite aerogel exhibits a continuous and uniform porous structure, with sheet-like molybdenum disulfide growing uniformly and vertically on the surface of the composite aerogel.

[0054] Figure 3This is a transmission electron microscope (TEM) image of the molybdenum disulfide-MXene / biomass carbon composite aerogel prepared in Example 1 of this invention. As shown in the image, the grown molybdenum disulfide has a size of approximately 500 nm.

[0055] Figures 4-5 This figure shows the adsorption efficiencies of the molybdenum disulfide-MXene / biomass carbon composite aerogel prepared in Example 1 of this invention for cesium and strontium ions, respectively. As can be seen from the figure, the adsorption capacities of the molybdenum disulfide-MXene / biomass carbon composite aerogel for cesium and strontium ions are 144.3 mg / g and 94.1 mg / g, respectively. Furthermore, under light irradiation, the adsorption equilibrium time for cesium and strontium ions by the composite aerogel can be shortened from 4 hours to 2 hours. This molybdenum disulfide-MXene / biomass carbon composite aerogel can promote the simultaneous adsorption of radioactive cesium and strontium ions based on solar energy.

[0056] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of a molybdenum disulfide-MXene / biomass carbon composite aerogel in the treatment of radioactive wastewater containing cesium and strontium ions, characterized in that, The preparation method of the molybdenum disulfide-MXene / biomass carbon composite aerogel includes the following steps: (1) Preparation of biomass carbon aerogel: Chitosan is dispersed in acetic acid solution and stirred to dissolve to obtain chitosan dispersion. Waste leather scrap hydrolysate is added and stirred evenly. Then glutaraldehyde crosslinking agent is added to carry out crosslinking reaction to obtain chitosan hydrogel. Chitosan aerogel is obtained by freeze drying. Then the chitosan aerogel is pyrolyzed in a tube furnace at 400-800℃ under an inert gas atmosphere to obtain biomass carbon aerogel. (2) Preparation of molybdenum disulfide / biomass carbon composite aerogel: The biomass carbon aerogel obtained in step (1) is soaked in a mixed solution of ammonium molybdate tetrahydrate and thiourea, and then sodium citrate is added. The aerogel is placed in a reaction vessel and hydrothermally reacted at 160-220 °C to obtain molybdenum disulfide / biomass carbon composite aerogel. (3) Preparation of molybdenum disulfide-MXene / biomass carbon composite aerogel: First, MXene was added to deionized water and dispersed by ultrasonication to obtain MXene dispersion. Polydiallyldimethylammonium chloride was added to positively modify MXene. Then, the molybdenum disulfide / biomass carbon composite aerogel obtained in step (2) was impregnated in the modified MXene dispersion to obtain molybdenum disulfide-MXene / biomass carbon composite aerogel.

2. The application according to claim 1, characterized in that, In step (1), the mass ratio of chitosan to waste leather hydrolysate is (3-10):

1.

3. The application according to claim 1, characterized in that, In step (2), the mass ratio of ammonium molybdate tetrahydrate to thiourea is 1:(1-5); and / or, the mass ratio of biomass carbon aerogel to the sum of the masses of ammonium molybdate tetrahydrate and thiourea is 1:(30-110).

4. The application according to claim 1, characterized in that, In step (2), the mass ratio of biomass carbon aerogel to sodium citrate is 1:(0.5-1.5).

5. The application according to claim 1, characterized in that, In step (3), the concentration of MXene dispersion is 0.01-3 mg / L.

6. The application according to claim 1, characterized in that, In step (2), the solid-liquid ratio of the mixed solution of ammonium molybdate tetrahydrate and thiourea is 1 g: (20-50) mL; and / or, in step (3), the solid-liquid ratio of molybdenum disulfide / biomass carbon composite aerogel to modified MXene dispersion is 1 g: (50-100) mL.

7. The application according to claim 1, characterized in that, In step (1), the chitosan aerogel is placed in a tube furnace and heated at 400-800℃ under a N2 atmosphere at 5℃·min. -1 The heating rate is pyrolysis for 2-8 hours.

Images