Carbon nanotube / clay mineral composite material as well as preparation method and application thereof

Abstract

The invention discloses a carbon nano tube / clay mineral composite material as well as a preparation method and application thereof. The composite material comprises a starch-derived carbon nano tube and thermally activated-acid-soluble halloysite, and the ratio of the carbon nano tube to the thermally activated-acid-soluble halloysite is adjusted according to the loading capacity of starch; the preparation method comprises the following steps: step 1, activation treatment of halloysite; step 2, preparing a starch / porous halloysite composite material; and step 3, preparing the carbon nano tube / clay mineral composite material. The carbon nanotube / clay mineral composite material prepared by the invention has high specific surface area, rich pore structure and good chemical stability; as a lead ion adsorption material, the maximum adsorption capacity on lead ions can be 588 mg / g or above, after multiple adsorption-desorption cycles, the adsorption performance can still be kept at a high level, and good reusability is shown; in addition, the carbon nano tube / clay mineral composite material also shows a relatively high adsorption rate and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a carbon nanotube / clay mineral composite material and a preparation method and application thereof. Background Art

[0002] As environmental pollution becomes increasingly prominent, heavy metal ion pollution has drawn particular attention. Lead ions, as a common heavy metal pollutant, pose serious risks to the ecological environment and human health.

[0003] Traditional lead ion adsorption materials have defects such as limited adsorption capacity and insufficient stability, making it difficult to meet increasingly stringent environmental protection requirements.

[0004] Therefore, the development of new and efficient lead ion adsorption materials is of great practical significance. Summary of the Invention

[0005] In view of this, the present invention provides a carbon nanotube / clay mineral composite material and a preparation method and application thereof.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A carbon nanotube / clay mineral composite material comprises starch-derived carbon nanotubes and heat-activated-acid-soluble halloysite. The ratio of the starch-derived carbon nanotubes to the heat-activated-acid-soluble halloysite is adjusted according to the starch loading amount. The composite material is named Hal-H-xC, wherein x is 0.1 to 10 and is the mass ratio of starch to heat-activated-acid-soluble halloysite.

[0008] A method for preparing a carbon nanotube / clay mineral composite material comprises the following steps:

[0009] Step 1: Activation of Halloysite

[0010] The halloysite is calcined in a muffle furnace to change its structure and make it loose and porous. The calcined halloysite is then added to a sulfuric acid solution to react, thereby generating a large number of micropores and mesoporous structures on the surface of the halloysite. After the reaction, the porous halloysite is obtained by filtering, washing, and drying.

[0011] Step 2: Preparation of starch / porous halloysite composites

[0012] Add an ammonia solution to a flask, then add the porous halloysite obtained in step 1, stir to uniformly disperse it, then add soluble starch, continue stirring to allow the starch to be fully adsorbed on the surface of the porous halloysite, transfer the mixture to a reactor, and perform a hydrothermal reaction. After the reaction is completed, take out the product, wash it to neutrality, and dry it to obtain a starch / porous halloysite composite material;

[0013] Step 3: Preparation of carbon nanotube / clay mineral composites

[0014] The starch / porous halloysite composite material obtained in step 2 is placed in a tube furnace and pyrolyzed under an inert gas atmosphere. After the pyrolysis is completed, the mixture is cooled to room temperature in the furnace to obtain a carbon nanotube / clay mineral composite material.

[0015] Preferably, in step 1, the calcination temperature is 500-800° C., the calcination time is 1-5 h, the concentration of the sulfuric acid solution is 1-5 mol / L, and the reaction is carried out at 60-90° C. for 1-5 h.

[0016] Preferably, in step 1, the pore size distribution is mainly concentrated in the range of 2-50 nm, and the specific surface area can reach 150-400 m 2 / g.

[0017] Preferably, in step 2, 200 mL of a 3-7 mol / L ammonia solution is added to a 1 L three-necked flask, and then 10 g of the porous halloysite obtained in step 1 is added to ensure that the liquid-solid ratio reaches 20:1; and the mixture is stirred at a speed of 200 r / min for more than 30 minutes.

[0018] Preferably, in step 2, 5 g of soluble starch with a degree of polymerization of 100-200 is added, and stirring is continued for 1 hour to allow the starch to be fully adsorbed on the surface of the porous halloysite.

[0019] Preferably, in step 2, the mixture is transferred into a 500 mL reactor, subjected to hydrothermal reaction at 160-200° C. for 6-12 h, washed with deionized water until neutral, and dried at 60° C.

[0020] Preferably, in step 3, the inert gas is N2, the heating rate of the pyrolysis treatment is 5-10°C / min, the pyrolysis temperature is 300-700°C, and the pyrolysis time is 2-5h.

[0021] Preferably, in step 3, the carbon nanotubes in the composite material have a length of 1-5 μm and a diameter of 20-50 nm, and are tightly combined with the clay mineral to form a three-dimensional network structure.

[0022] The invention relates to an application of a carbon nanotube / clay mineral composite material in the field of environmental governance.

[0023] Compared with the prior art, the present invention has achieved the following technical effects:

[0024] (1) The carbon nanotube / clay mineral composite material prepared by the present invention has a high specific surface area, rich pore structure and good chemical stability;

[0025] (2) The carbon nanotube / clay mineral composite material prepared by the present invention is used as a lead ion adsorption material, and its maximum adsorption capacity for lead ions can be above 588 mg / g. Moreover, after multiple adsorption-desorption cycles, the adsorption performance can still be maintained at a high level, showing good reusability;

[0026] (3) The carbon nanotube / clay mineral composite material prepared by the present invention also exhibits a relatively fast adsorption rate and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a graph showing the adsorption rate of lead ions by the composite material under different adsorption time conditions of the present invention;

[0028] Figure 2 This is a graph showing the adsorption rate and adsorption amount of lead ions by the composite material under different initial concentration conditions of the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The present invention discloses a carbon nanotube / clay mineral composite material, which comprises starch-derived carbon nanotubes and heat-activated-acid-soluble halloysite. The ratio of the carbon nanotubes and the heat-activated-acid-soluble halloysite can be adjusted according to the loading amount of the starch. The composite material is named Hal-H-xC, where x (0.1-10) is the mass ratio of starch to heat-activated-acid-soluble halloysite.

[0031] The present invention also discloses a method for preparing a carbon nanotube / clay mineral composite material, comprising the following steps:

[0032] Step 1: Activation of Halloysite

[0033] The halloysite is placed in a muffle furnace and calcined at 500-800°C for 1-5 hours to change the structure of the halloysite and make it loose and porous. The calcined halloysite is then added to a 1-5 mol / L sulfuric acid solution and reacted at 60-90°C for 1-5 hours to generate a large number of micropores and mesoporous structures on the surface of the halloysite. The pore size distribution is mainly concentrated in the range of 2-50 nm, and the specific surface area can reach 150-400 m2 / g. After the reaction, the porous halloysite is obtained by filtering, washing, and drying.

[0034] Step 2: Preparation of starch / porous halloysite composites

[0035] Add 200 mL of 3-7 mol / L ammonia solution to a 1 L three-necked flask, then add 10 g of the porous halloysite obtained in step 1, ensuring that the liquid-solid ratio reaches 20:1, and stir at a speed of 200 r / min for more than 30 min to uniformly disperse it. Then, add 5 g of soluble starch, the degree of polymerization of the soluble starch is 100-200, and continue stirring for 1 h to allow the starch to be fully adsorbed on the surface of the porous halloysite. Transfer the mixture to a 500 mL reactor and perform a hydrothermal reaction at 160-200 ° C for 6-12 h. After the reaction is completed, take out the product, wash it with deionized water until it is neutral, and dry it at 60 ° C to obtain a starch / porous halloysite composite material;

[0036] Step 3: Preparation of carbon nanotube / clay mineral composites

[0037] The starch / porous halloysite composite material obtained in step 2 is placed in a tube furnace and pyrolyzed under a N2 atmosphere at a heating rate of 5 to 10°C / min, a pyrolysis temperature of 300 to 700°C, and a pyrolysis time of 2 to 5 hours. After the pyrolysis is completed, the mixture is cooled to room temperature in the furnace to obtain a carbon nanotube / clay mineral composite material;

[0038] The carbon nanotubes in the composite material have a length of 1-5 μm and a diameter of 20-50 nm and are tightly combined with clay minerals to form a three-dimensional network structure.

[0039] The invention also discloses an application of a carbon nanotube / clay mineral composite material in the field of environmental management.

[0040] Example 1:

[0041] Step 1: Activation of Halloysite

[0042] 10 g of halloysite was weighed and placed in a muffle furnace and calcined at 600°C for 3 h. 10 g of the calcined halloysite was added to 100 mL of a 3 mol / L sulfuric acid solution and heated and stirred in an 80°C water bath for 4 h. After the reaction, the mixture was filtered, washed with deionized water until the filtrate was neutral, and dried to obtain porous halloysite.

[0043] Step 2: Preparation of starch / porous halloysite composites

[0044] A 1L three-necked flask was charged with 200mL of a 5mol / L ammonia solution, 10g of porous halloysite was weighed and added thereto, and the mixture was stirred at 500r / min for 30min. Then, 5g of soluble starch was added and stirred for 1h. The mixture was transferred to a 500mL reactor and subjected to hydrothermal reaction at 200°C for 8h. After the reaction was completed, the product was taken out, washed with deionized water until neutral, and dried at 60°C for 12h to obtain a starch / porous halloysite composite material.

[0045] Step 3: Preparation of carbon nanotube / clay mineral composites

[0046] The obtained starch / porous halloysite composite material was placed in a tube furnace, heated to 600°C at a heating rate of 10°C / min under a nitrogen atmosphere, and pyrolyzed for 3 hours. After the pyrolysis was completed, the mixture was cooled to room temperature in the furnace to obtain a carbon nanotube / clay mineral composite material;

[0047] The composite material was used to adsorb lead ions. 0.1 g of the composite material was added to 50 mL of a 100 mg / L lead ion solution and stirred at 150 r / min at room temperature. Samples were taken at 5 min, 10 min, 30 min, 60 min, 90 min, and 120 min to determine the lead ion concentration after adsorption. The adsorption rate of the composite material for lead ions under different adsorption time conditions was obtained as follows: Figure 1 As shown in the figure, the removal rate of lead ions is close to 80% after 5 minutes of adsorption, and the composite material exhibits a faster adsorption rate for lead ions.

[0048] Example 2:

[0049] Take 0.1g of the composite material in Example 1 and add it to 50mL of lead ion solution with different concentrations. Stir it at 150r / min at room temperature. After 30min, measure the lead ion concentration after adsorption. The adsorption rate and adsorption amount of the composite material for lead ions under different initial concentration conditions are as follows: Figure 2 As shown in the figure, the composite material exhibits excellent lead ion adsorption performance over a wide range of initial lead ion concentrations. When the initial concentration is below 1200 mg / L, the composite material maintains a lead ion removal rate exceeding 90%, with a maximum adsorption capacity exceeding 588 mg / g. This composite material demonstrates significant potential for practical applications.

[0050] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A carbon nanotube / clay mineral composite material, characterized in that: The composite material includes starch-derived carbon nanotubes and heat-activated-acid-soluble halloysite, wherein the ratio of the starch-derived carbon nanotubes and the heat-activated-acid-soluble halloysite is adjusted according to the loading amount of starch. The composite material is named Hal-H-xC, wherein x is 0.1 to 10 and is the mass ratio of starch to heat-activated-acid-soluble halloysite.

2. A method for preparing a carbon nanotube / clay mineral composite material, characterized in that: The following steps are involved: Step 1: Activation of Halloysite The halloysite is calcined in a muffle furnace to change its structure and make it loose and porous. The calcined halloysite is then added to a sulfuric acid solution to react, thereby generating a large number of micropores and mesoporous structures on the surface of the halloysite. After the reaction, the porous halloysite is obtained by filtering, washing, and drying. Step 2: Preparation of starch / porous halloysite composites Add an ammonia solution to a flask, then add the porous halloysite obtained in step 1, stir to uniformly disperse it, then add soluble starch, continue stirring to allow the starch to be fully adsorbed on the surface of the porous halloysite, transfer the mixture to a reactor, and perform a hydrothermal reaction. After the reaction is completed, take out the product, wash it to neutrality, and dry it to obtain a starch / porous halloysite composite material; Step 3: Preparation of carbon nanotube / clay mineral composites The starch / porous halloysite composite material obtained in step 2 is placed in a tube furnace and pyrolyzed under an inert gas atmosphere. After the pyrolysis is completed, the mixture is cooled to room temperature in the furnace to obtain a carbon nanotube / clay mineral composite material.

3. The method for preparing a carbon nanotube / clay mineral composite material according to claim 2, characterized in that: In the step 1, the calcination temperature is 500-800° C., the calcination time is 1-5 hours, the concentration of the sulfuric acid solution is 1-5 mol / L, and the reaction is carried out at 60-90° C. for 1-5 hours.

4. The method for preparing a carbon nanotube / clay mineral composite material according to claim 2, characterized in that: In step 1, the pore size distribution is mainly concentrated in the range of 2-50nm, and the specific surface area can reach 150-400m 2 / g.

5. The method for preparing a carbon nanotube / clay mineral composite material according to claim 2, characterized in that: In the step 2, 200 mL of a 3-7 mol / L ammonia solution was added to a 1 L three-necked flask, and 10 g of the porous halloysite obtained in the step 1 was added to ensure that the liquid-solid ratio reached 20:1; and the mixture was stirred at a speed of 200 r / min for more than 30 min.

6. The method for preparing a carbon nanotube / clay mineral composite material according to claim 2, characterized in that: In the step 2, 5 g of soluble starch with a degree of polymerization of 100-200 was added, and stirring was continued for 1 hour to allow the starch to be fully adsorbed on the surface of the porous halloysite.

7. The method for preparing a carbon nanotube / clay mineral composite material according to claim 2, characterized in that: In the step 2, the mixture is transferred into a 500 mL reactor, subjected to a hydrothermal reaction at 160-200° C. for 6-12 h, washed with deionized water until neutral, and dried at 60° C.

8. The method for preparing a carbon nanotube / clay mineral composite material according to claim 2, characterized in that: In step 3, the inert gas is N2, the heating rate of the pyrolysis treatment is 5-10°C / min, the pyrolysis temperature is 300-700°C, and the pyrolysis time is 2-5h.

9. The method for preparing a carbon nanotube / clay mineral composite material according to claim 2, characterized in that: In step 3, the carbon nanotubes in the composite material have a length of 1-5 μm and a diameter of 20-50 nm, and are tightly combined with the clay mineral to form a three-dimensional network structure.

10. Use of the carbon nanotube / clay mineral composite material according to claim 1 in the field of environmental governance.

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