A composite material with high adsorption performance, its preparation method and application

Abstract

The present invention relates to a composite material with high adsorption performance, its preparation method and application, belonging to the technical field of ion adsorption. The composite material is first prepared by using layered molybdenum boride as a growth template and loading nickel-cobalt hydrotalcite by a solvothermal method to obtain NiCo-LDH / MoB material, and then modifying the material with salt substances and acidic substances. Experimental results show that the composite material has good morphology, large specific surface area, and nickel-cobalt hydrotalcite and molybdenum boride in the structure are tightly combined, which can adsorb both anions and cations simultaneously. Among them, the ion adsorption capacity and removal rate of the composite material for methyl orange (MO) are as high as 307.5 mg·g-1 and 97.3% respectively, and the ion adsorption capacity and removal rate for methylene blue (MB) are as high as 83.2 mg·g-1 and 91.7% respectively. Compared with similar adsorption materials, its ion adsorption capacity and removal rate are significantly improved, thus having great practical value and application prospects in the treatment of ion dye wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of ion adsorption, and relates to a composite material with high adsorption performance, a preparation method thereof and an application thereof. Background Art

[0002] Water is the source of life and an important resource for people to maintain normal production and life. However, with the rapid development of industry, the resulting environmental pollution problems are becoming increasingly serious. For example, methyl orange (MO) and methylene blue (MB) are a type of ionic azo dyes, which are widely used in textile, leather, cosmetics, plastics, petroleum and other fields due to their excellent dyeing effects. Unfortunately, both belong to highly toxic and difficult-to-degrade organic compounds with stable chemical structures. When industrial dye wastewater containing MO and MB is directly discharged into the water environment without treatment, its toxicity and carcinogenicity will cause great harm to the entire ecosystem. Therefore, how to reduce the concentration of MO and MB dyes in water is an urgent problem to be solved currently.

[0003] In recent years, several techniques for removing methyl orange and methylene blue in water have been explored, including adsorption method, ion exchange method, biodegradation method, photocatalysis method, membrane filtration method and flocculation method, etc. Among these attempts, the adsorption method has attracted wide attention due to its advantages of high efficiency and low cost. Adsorbing materials such as activated graphene, clay, zeolite, metal oxide, etc. have been developed and utilized in large quantities. Although these materials have greatly promoted the development of the dye adsorption field, due to disadvantages such as small adsorption capacity (the ionic adsorption amounts for methyl orange and methylene blue are generally 100 mg·g -1 and 30 mg·g -1 ) respectively, large consumption, difficult regeneration, high preparation cost or short effective life, etc., it is very difficult to meet the treatment of a large amount of dye wastewater, especially the demand for ionic dye wastewater. Therefore, there is still an urgent need to find a suitable adsorbing material.

[0004] Hydrotalcite (LDH) is an anionic layered compound, and anions are distributed between layers to balance the layer charge. Based on the cationic and anionic groups between the lamellae, the LDH material can adsorb a large amount of cations and anions. In addition, the preparation process of the LDH material is simple, the raw materials are cheap, and industrial production can be realized. These advantages make the composite material based on hydrotalcite promising to be the best candidate for removing ionic dyes in dye wastewater. Summary of the Invention

[0005] In view of this, one of the purposes of the present invention is to provide a composite material with high adsorption performance; the second purpose of the present invention is to provide a preparation method of a composite material with high adsorption performance; the third purpose of the present invention is to provide an application of the composite material with high adsorption performance in removing methyl orange and / or methylene blue.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] 1. A preparation method of a composite material with high adsorption performance, the preparation method is as follows:

[0008] (1) Preparation of NiCo-LDH / MoB: Mix a water-soluble divalent metal cobalt salt, a water-soluble divalent metal nickel salt, hexamethylenetetramine and layered molybdenum boride evenly, place them in a solvent, then transfer them to a polytetrafluoroethylene reaction kettle, and react at 120-160 °C for 4-8 h to obtain a reaction product. The reaction product is centrifuged, filtered, washed with deionized water, and dried for more than 24 h to obtain NiCo-LDH / MoB;

[0009] The solvent is any one or several of water, methanol, ethanol or acetone;

[0010] (2) Preparation of a composite material with high adsorption performance: a. Place the NiCo-LDH / MoB described in step (1) in deionized water, then sequentially add a salt substance and acidic substance 1, mix evenly, seal, and let stand in a cool place for 4-6 h to obtain a standing liquid A; b. Continue to add acidic substance 2 to the standing liquid A, mix evenly, seal, and then let stand in a cool place for 4-6 h to obtain a standing liquid B; c. Repeat step b once on the basis of the standing liquid B, and after centrifugation and washing with deionized water, freeze-dry for 12 h to obtain a composite material with high adsorption performance;

[0011] The molar mass ratio of H in the NiCo-LDH / MoB, the salt substance and acidic substance 1 is 1:4-5:20-25, g:mmol:mmol; the molar mass ratio of H in the NiCo-LDH / MoB, the salt substance and acidic substance 2 is 1:4-5:20-25, g:mmol:mmol; + +

[0012] The salt substance is any one of KCl or NaCl; the acidic substance 1 is any one of HCl or H 2 SO 4 ; the acidic substance 2 is any one of HCl or H 2 SO 4

[0013] Preferably, the water-soluble divalent metal cobalt salt described in step (1) is any one or several of cobalt chloride, cobalt sulfate, cobalt carbonate or cobalt nitrate; the water-soluble divalent metal nickel salt is any one or several of nickel chloride, nickel sulfate, nickel carbonate or nickel nitrate.

[0014] ​​​Preferably, the molar mass ratio of the water-soluble divalent metal cobalt salt, the water-soluble divalent metal nickel salt, hexamethylenetetramine, and layered molybdenum boride in step (1) is 1.5:1.5:3:30-40, mmol:mmol:mmol:mg.

[0015] Preferably, the preparation method of the layered molybdenum boride in step (1) is as follows: MoAlB is dispersed in a 25% by mass NaOH solution, then transferred to a polytetrafluoroethylene reaction kettle, and hydrothermally treated at 200-250 °C for more than 36 h to obtain a reaction product. The reaction product is centrifuged and filtered until the pH of the filtrate is 7 to obtain layered molybdenum boride.

[0016] Preferably, the solvent in the 25% by mass NaOH solution is any one or more of water, methanol, ethanol, or acetone.

[0017] Preferably, the rotation speed of the centrifugation in steps (1) and (2) is 4500-6000 rpm, and the time is more than 5 min.

[0018] 2. A composite material with high adsorption performance prepared by the preparation method described above.

[0019] 3. Application of the composite material with high adsorption performance in removing methyl orange and / or methylene blue.

[0020] The beneficial effects of the present invention are as follows: The present invention provides a composite material with high adsorption performance. In the preparation process of this composite material, layered molybdenum boride is used as a growth template, and nickel-cobalt hydrotalcite material is loaded by the solvothermal method to construct a NiCo-LDH / MoB structure. Regular pores are generated after the structure is modified by salt substances and acidic substances, thereby increasing the interlayer distance of the nickel-cobalt hydrotalcite material and increasing the interlayer voids, and further improving the adsorption performance of the composite material for anions and cations. Experimental results show that the ion adsorption amounts of this material for methyl orange (MO) and methylene blue (MB) are as high as 307.5 mg·g -1 and 83.2 mg·g -1 , respectively. Compared with traditional adsorption materials, the ion adsorption level is significantly improved; at the same time, the ion removal rates for methyl orange and methylene blue can reach 97.3% and 91.7%, respectively, which are also excellent levels among similar adsorption materials. The excellent ion adsorption amount and ion removal rate make this composite material have great practical value and application prospects in the treatment of traditional ion dye wastewater.

[0021] The present invention also provides a preparation method of a composite material with high adsorption performance. This preparation method is simple and easy to operate and is suitable for large-scale production.

[0022] Other advantages, objects, and features of the present invention will be set forth in part in the description which follows and, in part, will be obvious to those having ordinary skill in the art upon examination of the following or may be learned from the practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter. Description of the Drawings

[0023] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0024] Figure 1 SEM image of the composite material with high adsorption performance in Example 1;

[0025] Figure 2 X-ray powder diffraction pattern of the composite material with high adsorption performance in Example 1;

[0026] Figure 3 Ion removal rate diagrams of the composite material with high adsorption performance in Example 1 for methyl orange and methylene blue;

[0027] Figure 4 Ion removal rate diagrams of the composite material with high adsorption performance in Example 2 for methyl orange and methylene blue;

[0028] Figure 5 Ion removal rate diagrams of the composite material with high adsorption performance in Example 3 for methyl orange and methylene blue;

[0029] Figure 6 Color change comparison diagrams of the adsorbent composite materials in Example 1 and Comparative Example 1 after adsorbing methylene blue and methyl orange, where (a) is the color change comparison diagram after adsorbing methylene blue and (b) is the color change comparison diagram after adsorbing methyl orange;

[0030] Figure 7 Adsorption effect comparison diagrams of the adsorbent composite materials in Example 1 and Comparative Example 1 for methyl orange at different times, where (a) is the adsorption effect comparison diagram of the adsorbent composite material in Comparative Example 1 for methyl orange at different times and (b) is the adsorption effect comparison diagram of the adsorbent composite material in Example 1 for methyl orange at different times;

[0031] Figure 8 Ion adsorption amount diagrams of the composite material with high adsorption performance in Example 1 for methyl orange and methylene blue;

[0032] Figure 9 Ion adsorption amount diagrams of the adsorbent composite material in Comparative Example 1 for methyl orange and methylene blue. Detailed Embodiments

[0033] The following specific examples illustrate the implementation modes of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0034] Example 1

[0035] A composite material with high adsorption performance, and its specific preparation method is as follows:

[0036] (1) Prepare layered molybdenum boride: Place 1 g of MoAlB in 60 mL of an aqueous NaOH solution with a mass fraction of 25%, then transfer it to a polytetrafluoroethylene reaction kettle, and hydrothermally react at 200 °C for 36 h to obtain a reaction product. Load the reaction product into a centrifuge tube and centrifuge at 5500 rpm for 5 min. After filtration, centrifuge again until the pH of the filtrate is 7 to obtain layered molybdenum boride;

[0037] (2) Prepare NiCo-LDH / MoB: Mix 1.5 mmol of Co(NO 3 ) 2 , 1.5 mmol of Ni(NO 3 ) 2 , 3 mmol of hexamethylenetetramine and 30 mg of the layered molybdenum boride in step (1) evenly in water, then transfer it to a tetrafluoroethylene reaction kettle, and react at 140 °C for 6 h to obtain a reaction product. Load the reaction product into a centrifuge tube and centrifuge at 5000 rpm for 6 min. After filtration, obtain a precipitate. The precipitate is washed with deionized water and dried for 24 h to obtain NiCo-LDH / MoB;

[0038] (3) Prepare a composite material with high adsorption performance: a. Take 1 g of NiCo-LDH / MoB in step (2) and place it in a beaker containing 1000 mL of deionized water. Then add 5 mmol of NaCl and 20 mmol of HCl in sequence. Subsequently, place the beaker on a magnetic stirrer and stir for 10 min, then seal the beaker mouth and let it stand in a cool place for 4 h to obtain a standing solution A; b. Add 20 mmol of HCl to the standing solution A, mix evenly, seal the beaker mouth, and then let it stand in a cool place for 4 h to obtain a standing solution B; c. Repeat step b once on the basis of the standing solution B, centrifuge at 5500 rpm for 5 min, wash 4 times with deionized water, and then freeze-dry for 12 h to obtain a composite material with high adsorption performance.

[0039] Example 2

[0040] A composite material with high adsorption performance, and its specific preparation method is as follows:

[0041] (1) Prepare layered molybdenum boride: Place 1 g of MoAlB in 80 mL of an aqueous NaOH solution with a mass fraction of 25%, then transfer it to a polytetrafluoroethylene reaction kettle, and hydrothermally react for 36 h at 250 °C to obtain a reaction product. Load the reaction product into a centrifuge tube and centrifuge at 5500 rpm for 5 min. After filtration, centrifuge again until the pH of the filtrate is 7 to obtain layered molybdenum boride;

[0042] (2) Prepare NiCo-LDH / MoB: Mix 1.5 mmol of CoCl 2 , 1.5 mmol of NiSO 4 , 3 mmol of hexamethylenetetramine and 40 mg of the layered molybdenum boride in step (1) evenly, place them in water, then transfer them to a tetrafluoroethylene reaction kettle, and react at 140 °C for 6 h to obtain a reaction product. Load the reaction product into a centrifuge tube and centrifuge at 5000 rpm for 6 min. After filtration, obtain a precipitate. The precipitate is washed with deionized water and dried for 24 h to obtain NiCo-LDH / MoB;

[0043] (3) Prepare a composite material with high adsorption performance: a. Take 1 g of NiCo-LDH / MoB in step (2) and place it in a beaker containing 1000 mL of deionized water. Then, add 4 mmol of NaCl and 20 mmol of HCl in sequence. Subsequently, place the beaker on a magnetic stirrer and stir for 10 min, then seal the beaker mouth and let it stand in a cool place for 4 h to obtain a standing liquid A; b. Add 20 mmol of HCl to the standing liquid A, mix evenly, seal the beaker mouth, and then let it stand in a cool place for 4 h to obtain a standing liquid B; c. Repeat step b once on the basis of the standing liquid B, centrifuge at 5500 rpm for 5 min, wash 4 times with deionized water, and then freeze-dry for 12 h to obtain a composite material with high adsorption performance.

[0044] Example 3

[0045] A composite material with high adsorption performance, and its specific preparation method is as follows:

[0046] (1) Prepare layered molybdenum boride: Place 1 g of MoAlB in 100 mL of an aqueous NaOH solution with a mass fraction of 25%, then transfer it to a polytetrafluoroethylene reaction kettle, and hydrothermally react for 36 h at 250 °C to obtain a reaction product. Load the reaction product into a centrifuge tube and centrifuge at 5500 rpm for 5 min. After filtration, centrifuge again until the pH of the filtrate is 7 to obtain layered molybdenum boride;

[0047] (2) Preparation of NiCo-LDH / MoB: 1.5 mmol of CoSO 4 、1.5 mmol of NiCO 3 、3 mmol of hexamethylenetetramine and 40 mg of the layered molybdenum boride in step (1) were mixed evenly and placed in water, then transferred to a Teflon reactor and reacted at 140 °C for 6 h to obtain a reaction product. The reaction product was placed in a centrifuge tube and centrifuged at 5000 rpm for 6 min, and after filtration, a precipitate was obtained. The precipitate was washed with deionized water and dried for 24 h to obtain NiCo-LDH / MoB;

[0048] (3) Preparation of a composite material with high adsorption performance: a. Take 1 g of NiCo-LDH / MoB in step (2) and place it in a beaker containing 1000 mL of deionized water, then successively add 4 mmol of KCl and 10 mmol of H 2 SO 4 , and then place the beaker on a magnetic stirrer and stir for 10 min, then seal the beaker mouth and let it stand in a cool place for 4 h to obtain a standing solution A; b. Add 20 mmol of HCl to the standing solution A, mix evenly, seal the beaker mouth, and then let it stand in a cool place for 4 h to obtain a standing solution B; c. Repeat step b once on the basis of the standing solution B, centrifuge at 5500 rpm for 5 min, wash 4 times with deionized water, and then freeze-dry for 12 h to obtain a composite material with high adsorption performance.

[0049] Comparative Example 1

[0050] An adsorptive composite material, and the specific preparation method of the composite material is as follows:

[0051] (1) Preparation of layered molybdenum boride: 1 g of MoAlB was placed in 60 mL of 25% NaOH aqueous solution by mass fraction, then transferred to a Teflon reactor and hydrothermally reacted at 200 °C for 36 h to obtain a reaction product. The reaction product was placed in a centrifuge tube and centrifuged at 5500 rpm for 5 min, and after filtration, centrifuged again until the pH of the filtrate was 7 to obtain layered molybdenum boride;

[0052] (2) Preparation of NiCo-LDH / MoB: 1.5 mmol of Co(NO 3 ) 2 、1.5 mmol of Ni(NO 3 ) 2, 3 mmol of hexamethylenetetramine and 30 mg of the layered molybdenum boride in step (1) were mixed evenly, placed in water, then transferred to a Teflon reaction kettle, and reacted at 140 °C for 6 h to obtain a reaction product. The reaction product was loaded into a centrifuge tube and centrifuged at 5000 rpm for 6 min, and after filtration, a precipitate was obtained. The precipitate was washed with deionized water and dried for 24 h to obtain NiCo-LDH / MoB.

[0053] Figure 1 It is the scanning electron micrograph of the composite material with high adsorption performance in Example 1. From Figure 1 it can be seen that the morphology of this composite material is good, the specific surface area is relatively large, and molybdenum boride is tightly combined with nickel-cobalt hydrotalcite. It can be predicted that this composite material has excellent ion adsorption performance.

[0054] Figure 2 It is the X-ray powder diffraction pattern of the composite material with high adsorption performance in Example 1. From Figure 2 it can be seen that the characteristic diffraction peaks of NiCo-LDH and MoB exist in this composite material, which indicates that the composite material in Example 1 was successfully prepared and no other products were produced.

[0055] Similarly, the scanning electron microscopy and X-ray powder diffraction tests were carried out on the composite materials with high adsorption performance in Examples 2-3, and experimental results similar to those of the composite material in Example 1 were obtained, indicating that the composite materials in Examples 2-3 were also successfully prepared, with good morphology, large specific surface area, and tight combination of molybdenum boride and nickel-cobalt hydrotalcite.

[0056] Performance Test

[0057] 1. Explore the removal effects of the composite materials with high adsorption performance in Examples 1-3 on methyl orange and methylene blue

[0058] The relationship diagrams of the ion removal rates and time of the composite materials with high adsorption performance in Examples 1-3 on methyl orange and methylene blue were respectively plotted. Among them, Figure 3 it is the ion removal rate diagram of the composite material with high adsorption performance in Example 1 on methyl orange and methylene blue. From Figure 3 it can be seen that the ion removal rate of the composite material in Example 1 on methyl orange is 97.3%, and the ion removal rate on methylene blue is 91.7%. Figure 4 it is the ion removal rate diagram of the composite material with high adsorption performance in Example 2 on methyl orange and methylene blue. From Figure 4 it can be seen that the ion removal rate of the composite material in Example 2 on methyl orange is 94.1%, and the ion removal rate on methylene blue is 87.2%. Figure 5 it is the ion removal rate diagram of the composite material with high adsorption performance in Example 3 on methyl orange and methylene blue. From Figure 5It can be seen that the ion removal rate of the composite material in Example 3 for methyl orange is 92.78%, and the ion removal rate for methylene blue is 85.73%. In summary, the ion removal rate of the composite material in this application is high, indicating that it can effectively remove the two ionic dyes, methylene blue and methyl orange, in wastewater.

[0059] 2. Explore the adsorption effects of the composite material with high adsorption performance in Example 1 on methyl orange and methylene blue

[0060] The composite materials in Example 1 and Comparative Example 1 were respectively placed in methylene blue solution and methyl orange solution. After 60 minutes, the adsorption of each adsorbent material on the two solutions was observed respectively. The experimental results are as Figure 6 shown in (a) and (b). It can be seen from the change in the color depth of the solution that whether it is methylene blue solution or methyl orange solution, the adsorption effect of the composite material in Example 1 is significantly better than that of the composite material in Comparative Example 1.

[0061] The composite materials in Example 1 and Comparative Example 1 were respectively placed in methyl orange solution, and then the adsorption of each adsorbent material on methyl orange solution was observed at 0 min, 5 min, 10 min, 20 min, and 60 min. The experimental results are as Figure 7 shown in (a) and (b). It can be seen from the change in the color depth of the solution that the adsorption effect of the composite material in Example 1 is significantly better than that of the composite material in Comparative Example 1.

[0062] To determine the actual adsorption amount, the relationship diagrams of the ion adsorption amounts of the composite materials in Example 1 and Comparative Example 1 for methyl orange and methylene blue versus time were respectively plotted. The experimental results are as Figure 8 and Figure 9 shown. Among them, Figure 8 is the ion adsorption amount diagram of the composite material with high adsorption performance in Example 1 for methyl orange and methylene blue. It can be seen that: the ion adsorption amount of this composite material for methyl orange can reach 307.5 mg·g -1 , and the ion adsorption amount for methylene blue can reach 83.2 mg·g -1 . Compared with the currently achievable adsorption amounts (the ion adsorption amounts of methyl orange and methylene blue are generally 100 mg·g -1 and 30 mg·g -1 respectively), its ion adsorption amount is significantly improved, indicating that this material has excellent adsorption performance. Figure 9 is the ion adsorption amount diagram of the adsorbent composite material in Comparative Example 1 for methyl orange and methylene blue. It can be seen that: the ion adsorption amount of this composite material for methyl orange is 88 mg·g -1 , and the ion adsorption amount for methylene blue is 62 mg·g -1That is, compared with the material modified by acidic substances and salt substances (the composite material in Example 1), the ion adsorption amount is lower, indicating poor adsorption performance.

[0063] In summary, the present invention provides a composite material with high adsorption performance. During the preparation process of this composite material, the NiCo-LDH / MoB structure is first established, and then the structure is modified with salt substances and acidic substances to generate regular pores in the structure, thereby increasing the interlayer distance of the nickel-cobalt hydrotalcite material and increasing the interlayer voids, and further improving the adsorption performance of the composite material for anions and cations. Compared with similar adsorption materials, the adsorption amount of methyl orange (MO) and methylene blue (MB) and the ion removal rate of this composite material are significantly improved, thus having great practical value and application prospects in the treatment of traditional ionic dye wastewater. Its preparation method is simple and easy to operate, and is suitable for large-scale production.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. Preparation method of a composite material with high adsorption performance, Characterized in that: The preparation method is as follows: (1) Preparation of NiCo-LDH / MoB: A water-soluble divalent metal cobalt salt, a water-soluble divalent metal nickel salt, hexamethylenetetramine and layered molybdenum boride are mixed evenly and placed in a solvent, and then transferred to a polytetrafluoroethylene reaction kettle, and reacted at 120-160 °C for 4-8 h to obtain a reaction product. The reaction product is centrifuged, filtered, washed with deionized water, and dried for more than 24 h to obtain NiCo-LDH / MoB; The solvent is any one or several of water, methanol, ethanol or acetone; (2) Preparation of a composite material with high adsorption performance: a. Place the NiCo-LDH / MoB described in step (1) in deionized water, then sequentially add a salt substance and acidic substance 1, mix evenly and seal, and let it stand in a cool place for 4-6 h to obtain a standing liquid A; b. Continue to add acidic substance 2 to the standing liquid A, mix evenly and seal, and then let it stand in a cool place for 4-6 h to obtain a standing liquid B; c. Repeat step b once on the basis of the standing liquid B, and after centrifugation and washing with deionized water, freeze-dry for 12 h to obtain a composite material with high adsorption performance; The molar mass ratio of the NiCo-LDH / MoB, the salt substance, and H in the acidic substance 1 is 1:4 to 5:20 to 25, g:mmol:mmol; the molar mass ratio of the NiCo-LDH / MoB, the salt substance, and H in the acidic substance 2 is 1:4 to 5:20 to 25, g:mmol:mmol; + The molar mass ratio of the NiCo-LDH / MoB, the salt substance, and H in the acidic substance 1 is 1:4 to 5:20 to 25, g:mmol:mmol; the molar mass ratio of the NiCo-LDH / MoB, the salt substance, and H in the acidic substance 2 is 1:4 to 5:20 to 25, g:mmol:mmol; + The molar mass ratio of the NiCo-LDH / MoB, the salt substance, and H in the acidic substance 2 is 1:4 to 5:20 to 25, g:mmol:mmol; The salt substance is any one of KCl or NaCl; the acidic substance 1 is any one of HCl or H 2 SO 4 ; the acidic substance 2 is any one of HCl or H 2 SO 4 .

2. The preparation method according to claim 1, Characterized in that: The water-soluble divalent metal cobalt salt described in step (1) is any one or several of cobalt chloride, cobalt sulfate or cobalt nitrate; the water-soluble divalent metal nickel salt is any one or several of nickel chloride, nickel sulfate or nickel nitrate.

3. The preparation method according to claim 1, Characterized in that: The molar mass ratio of the water-soluble divalent metal cobalt salt, the water-soluble divalent metal nickel salt, hexamethylenetetramine and layered molybdenum boride in step (1) is 1.5:1.5:3:30-40, mmol:mmol:mmol:mg.

4. The preparation method according to claim 1, Characterized in that: The preparation method of the layered molybdenum boride in step (1) is: Disperse MoAlB in a 25% by mass NaOH solution, and then transfer it to a polytetrafluoroethylene reaction kettle, and hydrothermally react at 200-250 °C for more than 36 h to obtain a reaction product. The reaction product is centrifuged and filtered until the pH of the filtrate is 7 to obtain layered molybdenum boride.

5. The preparation method according to claim 4, Characterized in that: The solvent in the 25% by mass NaOH solution is any one or several of water, methanol, ethanol or acetone.

6. The preparation method according to claim 1, Characterized in that: The rotation speed of the centrifugation in steps (1) and (2) is 4500-6000 rpm and the time is more than 5 min.

7. A composite material with high adsorption performance prepared by the preparation method according to any one of claims 1-6.

8. Application of the composite material with high adsorption performance according to claim 7 in removing methyl orange and / or methylene blue.

Images