NZVMn-MXene composite alginate aerogel microsphere and preparation method thereof

Abstract

According to the nZVMn-MXene composite alginate aerogel microspheres and the preparation method thereof, compared with a traditional MXene material, the nZVMn-MXene composite alginate aerogel microspheres are small in particle size, multiple in active site and high in reducibility and adsorbability, and the removal effect of pollutants in a water body can be effectively improved. Sodium alginate is rich in carboxyl, hydroxyl and other functional groups, is a non-toxic and renewable biomass high-molecular polymer, can be cross-linked with divalent cations to prepare gels in different shapes, and is widely applied to carriers of powdery adsorbents. The nZVMn-MXene composite alginate aerogel microspheres are prepared by loading the nZVMn-MXene onto the alginate, and can be used for removing pollutants in a water body, so that the problem that the adsorbed bottom mud is difficult to treat is solved. The aerogel is uniform in particle size, the particle diameter is 0.1-5 mm, and the adsorption capacity of Pb < 2 + >, Cu < 2 + >, Cs < + > and U (VI) reaches 60-500 mg / g.

Description

Technical Field

[0001] The invention belongs to the technical field of functional polymer materials, and specifically relates to nZVMn-MXene composite alginate aerogel microspheres for removing water pollutants and a preparation method thereof. Background Art

[0002] MXene materials have the advantages of large specific surface area, controllable interlayer spacing and good hydrophilicity, and are widely used in water pollution treatment, antibacterial sterilization, seawater desalination, catalysis and other fields. Compared with traditional MXene materials, nZVMn-MXene materials have small particle size, more active sites, strong reducibility and adsorption, and can effectively improve the removal effect of pollutants in water.

[0003] In recent years, aerogels have attracted more and more attention from researchers due to their large specific surface area, controllable shape and composition, and low density. Sodium alginate is rich in functional groups such as carboxyl and hydroxyl groups. It is a non-toxic, renewable biomass polymer that can be cross-linked with divalent cations to prepare gels of different shapes and has been widely used as a carrier for powdered adsorbents. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The present invention proposes a nZVMn-MXene composite alginate aerogel microsphere and a preparation method thereof, so as to solve the technical problem of how to improve the adsorption effect of MXene materials and solve the difficult treatment of sediment after adsorption.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention proposes a method for preparing nZVMn-MXene composite alginate aerogel microspheres. The preparation method is: adding nZVMn-MXene to a sodium alginate solution, uniformly dispersing the mixed solution and then adding it dropwise to a CaCl2 solution, filtering the obtained product, rinsing and freeze-drying it to obtain nZVMn-MXene composite alginate aerogel microspheres.

[0008] Furthermore, the preparation method of nZVMn-MXene is:

[0009] S1. Ti3AlC2 is slowly added to an etching solution of HCl and LiF, stirred and dispersed evenly under an Ar atmosphere, and the supernatant is removed after centrifugation to obtain MXene;

[0010] S2. Add MXene to KOH solution, stir under Ar atmosphere, rinse and freeze-dry to obtain OH-MXene powder;

[0011] S3. Disperse OH-MXene powder evenly in MnCl2 solution, stir until evenly dispersed, add NaBH4 solution dropwise into the above solution, centrifuge and freeze-dry the precipitate to obtain nZVMn-MXene.

[0012] Furthermore, in step S1, the weight ratio of the Ti3AlC2 solution, the HCl solution, and the LiF solution is 1:(2-50):(1-20).

[0013] Furthermore, in step S1, the stirring time is 24 to 48 hours, and the concentration of the HCl solution is 10% to 50%.

[0014] Furthermore, in step S2, the weight ratio of MXene to KOH solution is 1:(2-100).

[0015] Furthermore, in step S2, the stirring time is 1 to 24 hours, and the concentration of the KOH solution is 5% to 30%.

[0016] Furthermore, in step S3, the weight ratio of OH-MXene powder, MnCl2 solution, and NaBH4 solution is 1:(5-500):(2-50).

[0017] Furthermore, in step S3, the concentration of the MnCl2 solution is 2% to 75%, and the concentration of the NaBH4 solution is 0.5% to 10%, and stirring is continued at 30 to 50°C until the mixture is evenly dispersed.

[0018] Furthermore, the weight ratio of nZVMn-MXene, sodium alginate solution, and CaCl2 solution is 1:(1-100):(1-500), the concentration of sodium alginate solution is 1%-10%, and the concentration of CaCl2 solution is 1%-10%.

[0019] In addition, the present invention also proposes a nZVMn-MXene composite alginate aerogel microsphere, and the nZVMn-MXene composite alginate aerogel microsphere is prepared by the above method.

[0020] (III) Beneficial effects

[0021] The present invention proposes a nZVMn-MXene composite alginate aerogel microsphere and a preparation method thereof. Compared with traditional MXene materials, nZVMn-MXene materials have small particle size, more active sites, stronger reducibility and adsorption, and can effectively improve the removal effect of pollutants in water bodies. Sodium alginate is rich in functional groups such as carboxyl and hydroxyl groups. It is a non-toxic and renewable biomass macromolecular polymer that can be cross-linked with divalent cations to prepare gels of different shapes and has been widely used as a carrier for powdered adsorbents. The present invention loads nZVMn-MXene onto alginate to prepare nZVMn-MXene composite alginate aerogel microspheres, which can be used to remove pollutants in water bodies and solve the problem of difficult treatment of sediment after adsorption. The aerogel has uniform particle size, with a particle diameter of 0.1 to 5 mm, and has good performance for Pb 2+ , Cu 2+ , Cs + , the adsorption amount of U(VI) reaches 60-500 mg / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1a is the Langmuir model adsorption isotherm of nZVMn-MXene for U(VI), Figure 1b is the adsorption isotherm of the Freundich model;

[0023] Figure 2a is the pseudo-first-order kinetic model adsorption kinetic curve of nZVMn-MXene for U(VI), Figure 2b This is the adsorption kinetic curve of the pseudo-second-order kinetic model. DETAILED DESCRIPTION

[0024] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0025] Example 1

[0026] This embodiment provides a method for preparing nZVMn-MXene composite alginate aerogel, comprising the following steps:

[0027] (1) 1 g of Ti3AlC2 was slowly added to an etching solution of 20 g of 50% HCl and 1 g of LiF, stirred for 24 h, stirred and dispersed evenly under an Ar atmosphere, and the supernatant was removed after centrifugation to obtain MXene;

[0028] (2) 1 g of MXene was added to 10 g of 5% KOH solution, stirred for 5 h under Ar atmosphere, and then freeze-dried after washing to obtain OH-MXene powder;

[0029] (3) 1 g of OH-MXene powder was uniformly dispersed in 50 g of 10% MnCl2 solution, and the mixture was continuously stirred at 30°C until uniformly dispersed. 2 g of 2% NaBH4 solution was dripped into the above solution dropwise, and the precipitate was freeze-dried after centrifugation to obtain nZVMn-MXene (i.e., nZVMn modified MXene);

[0030] (4) 1 g of nZVMn-MXene was added to 50 g of 1% sodium alginate solution. The resulting mixture was evenly dispersed and then added dropwise to 50 g of 1% CaCl2 solution. The resulting product was filtered, rinsed with water, and freeze-dried to obtain nZVMn-MXene composite alginate aerogel microspheres.

[0031] Example 2

[0032] This embodiment provides a method for preparing nZVMn-MXene composite alginate aerogel, comprising the following steps:

[0033] (1) 1 g of Ti3AlC2 was slowly added to an etching solution of 2 g of 10% HCl and 1 g of LiF, stirred for 24 h, stirred and dispersed evenly under an Ar atmosphere, and the supernatant was removed after centrifugation to obtain MXene;

[0034] (2) 1 g of MXene was added to 2 g of 5% KOH solution, stirred for 1 h under Ar atmosphere, and then freeze-dried after rinsing to obtain OH-MXene powder;

[0035] (3) 1 g of OH-MXene powder was uniformly dispersed in 5 g of 2% MnCl2 solution, and the mixture was continuously stirred at 30 °C until uniformly dispersed. 2 g of 0.5% NaBH4 solution was dripped into the above solution dropwise, and the precipitate was freeze-dried after centrifugation to obtain nZVMn-MXene.

[0036] (4) 1 g of nZVMn-MXene was added to 1 g of 1% sodium alginate solution. The resulting mixture was evenly dispersed and then added dropwise to 1 g of 1% CaCl2 solution. The resulting product was filtered, rinsed with water, and freeze-dried to obtain nZVMn-MXene composite alginate aerogel microspheres.

[0037] Example 3

[0038] This embodiment provides a method for preparing nZVMn-MXene composite alginate aerogel, comprising the following steps:

[0039] (1) 1 g of Ti3AlC2 was slowly added to an etching solution of 50 g of 50% HCl and 20 g of LiF, stirred for 48 h, stirred and dispersed evenly under an Ar atmosphere, and the supernatant was removed after centrifugation to obtain MXene;

[0040] (2) 1 g of MXene was added to 100 g of 30% KOH solution, stirred for 24 h under Ar atmosphere, and freeze-dried after washing to obtain OH-MXene powder;

[0041] (3) 1 g of OH-MXene powder was uniformly dispersed in 500 g of 75% MnCl2 solution, and the mixture was continuously stirred at 50 °C until uniformly dispersed. 50 g of 10% NaBH4 solution was dripped into the above solution dropwise, and the precipitate was freeze-dried after centrifugation to obtain nZVMn-MXene.

[0042] (4) 1 g of nZVMn-MXene was added to 100 g of 10% sodium alginate solution. The resulting mixture was evenly dispersed and then added dropwise to 500 g of 10% CaCl2 solution. The resulting product was filtered, rinsed with water, and freeze-dried to obtain nZVMn-MXene composite alginate aerogel microspheres.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing nZVMn-MXene composite alginate aerogel microspheres, characterized in that: The preparation method comprises the following steps: adding nZVMn-MXene to a sodium alginate solution, uniformly dispersing the mixed solution and then adding the mixed solution dropwise to a CaCl2 solution, filtering the obtained product, and freeze-drying the product after washing to obtain nZVMn-MXene composite alginate aerogel microspheres.

2. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: The preparation method of the nZVMn-MXene is: S1. Ti3AlC2 is slowly added to an etching solution of HCl and LiF, stirred and dispersed evenly under an Ar atmosphere, and the supernatant is removed after centrifugation to obtain MXene; S2. Add MXene to KOH solution, stir under Ar atmosphere, rinse and freeze-dry to obtain OH-MXene powder; S3. Disperse OH-MXene powder evenly in MnCl2 solution, stir until evenly dispersed, add NaBH4 solution dropwise into the above solution, centrifuge and freeze-dry the precipitate to obtain nZVMn-MXene.

3. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: In step S1, the weight ratio of Ti3AlC2 solution, HCl solution and LiF solution is 1:(2-50):(1-20).

4. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: In step S1, the stirring time is 24 to 48 hours, and the concentration of the HCl solution is 10% to 50%.

5. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: In step S2, the weight ratio of MXene to KOH solution is 1:(2-100).

6. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: In step S2, the stirring time is 1 to 24 hours, and the concentration of the KOH solution is 5% to 30%.

7. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: In step S3, the weight ratio of OH-MXene powder, MnCl2 solution, and NaBH4 solution is 1:(5-500):(2-50).

8. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: In step S3, the concentration of the MnCl2 solution is 2% to 75%, and the concentration of the NaBH4 solution is 0.5% to 10%, and stirring is continued at 30 to 50°C until the mixture is evenly dispersed.

9. The method for preparing nZVMn-MXene composite alginate aerogel microspheres according to claim 1, characterized in that: The weight ratio of nZVMn-MXene, sodium alginate solution and CaCl2 solution is 1:(1-100):(1-500), the concentration of sodium alginate solution is 1%-10%, and the concentration of CaCl2 solution is 1%-10%.

10. A nZVMn-MXene composite alginate aerogel microsphere, characterized in that: The nZVMn-MXene composite alginate aerogel microspheres are prepared by the method described in any one of claims 1 to 9.

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