Method for enriching light metal ions in pore channel based on carbon nanofiber / carbon fiber nanometer confinement

Abstract

The invention discloses a method for enriching light metal ions in a pore channel based on carbon nanofiber / carbon fiber nano confinement, and belongs to the technical field of sample pretreatment, and the method comprises the following steps: S1, preparing a carbon nanofiber / carbon fiber confinement material; and S2, putting the carbon nanofiber / carbon fiber confinement material obtained in S1 into a light metal ion solution, and stirring. According to the method for enriching the light metal ions in the pore channel based on the carbon nanofiber / carbon fiber nano confinement, the carbon nanofiber / carbon fiber is used as a confinement fluid carrier, ultrapure water, methanol or n-hexane is used as an extracting agent, a chelating agent does not need to be introduced, the method is green and environmentally friendly, the mass transfer rate is increased, and the method is suitable for large-scale industrial production. Therefore, high enrichment of light metal ions in water is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of sample pretreatment, and in particular to a method for enriching light metal ions in carbon nanofiber / carbon fiber nano-confined pores. Background Art

[0002] Metal ions refer to metal element ions formed after a certain substance is dissolved in water. Among them, light metal ions (Na + , K + , Ca 2+ , Mg 2+ , Al 3+ , Li + ) are not only indispensable metal elements for living organisms, but also play an important role in industrial applications. Light metal alloys have a wide range of applications in military industries such as aircraft and ships, and civilian enterprises due to their low density and excellent heat resistance. Therefore, enriching light metal ions in water is of great significance for various application scenarios.

[0003] Traditional methods for enriching light metal ions mainly include physical (electrostatic) adsorption, chemical adsorption, adsorption in the form of complexes or precipitates, reaction with flotation reagents, and ion exchange with the mineral surface. For example, physical (electrostatic) adsorption adsorbs light metal ions by changing the surface charge of the material; chemical adsorption mainly enhances the adsorption ability of light metal ions by increasing the active sites of the material; light metal ions can also be adsorbed on the material surface through hydrolysis to form hydroxy complexes or hydroxide precipitates, thereby achieving enrichment. However, the above methods have the disadvantages of complex material preparation processes, introduction of new impurities, and the need to consume a large amount of time and energy, which hinder the process of enriching light metal ions.

[0004] The proposed liquid-phase nanoextraction technology provides a new idea for the enrichment of light metal ions in water. Based on the size effect and interface effect of nano-confinement, liquid-phase nanoextraction uses multi-dimensional pores as the confined fluid extraction unit to achieve efficient separation and enrichment. Thermodynamic and kinetic studies show that the extraction process not only occurs spontaneously, but also has the characteristics of rapid mass transfer and high throughput. Therefore, liquid-phase nanoextraction technology is expected to provide a new idea for the enrichment of light metal ions in water that is simple, fast, and environmentally friendly. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for enriching light metal ions in carbon nanofiber / carbon fiber nano-confined pores, using carbon nanofiber / carbon fiber as the confined fluid carrier and ultrapure water, methanol, or n-hexane as the extraction agent, without the need to introduce chelating agents, which is not only environmentally friendly but also accelerates the mass transfer rate, thereby achieving high enrichment of light metal ions in water.

[0006] To achieve the above object, the present invention provides a method for enriching light metal ions in carbon nanofiber / carbon fiber nano-confined pores, comprising the following steps:

[0007] S1. Prepare a carbon nanofiber / carbon fiber confined material;

[0008] S2. Place the carbon nanofiber / carbon fiber confined material obtained in S1 into a light metal ion solution and stir.

[0009] Preferably, the specific steps of S1 are: lay the carbon nanofiber / carbon fiber flat between two pieces of filter paper, then place it in a Buchner funnel, slowly drip the confined solvent for suction filtration. After the carbon nanofiber / carbon fiber is moistened, stop the suction filtration and take out the carbon nanofiber / carbon fiber confined material.

[0010] Preferably, the confined solvent is one of ultrapure water, methanol, and n-hexane.

[0011] Preferably, the ratio of the confined solvent to the carbon nanofiber / carbon fiber in the confined material is: 1 mg of carbon nanofiber / carbon fiber corresponds to 2.86 - 5.72 μL of the confined solvent.

[0012] Preferably, the pH value of the light metal ion solution is 3 - 9.

[0013] Preferably, the light metal ions in the light metal ion solution are Na + , K + , Ca 2+ , Mg 2+ , Al 3+ , Li + or one of them.

[0014] Preferably, the stirring speed is 400 - 800 rpm / min and the stirring time is 1 - 7 min.

[0015] Therefore, the present invention adopts the above method for enriching light metal ions in carbon nanofiber / carbon fiber nano-confined pores, and has the following beneficial effects:

[0016] (1) Using carbon nanofiber / carbon fiber as the confined fluid carrier and ultrapure water, methanol or n-hexane as the extractant, no chelating agent needs to be introduced, which is green and environmentally friendly;

[0017] (2) Carbon nanofiber / carbon fiber confines water at the nanoscale. The confined water not only interacts with the nanopore wall to affect the hydrogen bond configuration and dynamics of water, but also interacts with light metal ions to affect the dynamics of light metal ions, enabling their rapid mass transfer, thereby achieving rapid and high enrichment of light metal ions.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0019] Figure 1 It is a Fourier-infrared characterization diagram of carbon nanofiber / carbon fiber confinement material and carbon nanofiber / carbon fiber in Example 1 of a method for enriching light metal ions in carbon nanofiber / carbon fiber nano-confined pores according to the present invention;

[0020] Figure 2 It is an extraction recovery rate diagram of carbon nanofiber / carbon fiber confined water for different light metal ions in an embodiment of a method for enriching light metal ions in carbon nanofiber / carbon fiber nano-confined pores according to the present invention. Detailed Embodiments

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs.

[0023] Main reagents and instruments used: A PXSJ-226T ion-selective electrode (ISE, Leici, China) was used to detect the concentration of light metal ions, a magnetic stirrer (Shanghai Huxi Analytical Instrument Factory Co., Ltd.), chromatographic grade methanol and n-hexane (SigmaAldrich).

[0024] Example 1

[0025] A method for enriching light metal ions in carbon nanofiber / carbon fiber nano-confined pores includes the following steps:

[0026] S1. Prepare carbon nanofiber / carbon fiber confined water: Lay 3.5 g of carbon nanofiber / carbon fiber flat between two pieces of filter paper, then place it in a Buchner funnel, and connect the filtration device to a peristaltic pump. Slowly drip ultrapure water and perform suction filtration. After the carbon nanofiber / carbon fiber is moistened, stop suction filtration and take out the carbon nanofiber / carbon fiber confined water. Among them, the ratio of ultrapure water to carbon nanofiber / carbon fiber in the carbon nanofiber / carbon fiber confined water is: 1 mg of carbon nanofiber / carbon fiber corresponds to 5.72 μL of ultrapure water.

[0027] S2. Suspend the carbon nanofiber / carbon fiber confined water obtained in S1 in 10 mL of a Na + solution with a pH value of 8, and stir at a speed of 400 rpm / min for 5 min to obtain carbon nanofiber / carbon fiber confined water enriched with Na + .

[0028] Example 2

[0029] In Example 2, which is different from Example 1, the light metal ion solution is a K + solution, and carbon nanofiber / carbon fiber-confined water enriched with K + is obtained.

[0030] Example 3

[0031] In Example 3, which is different from Example 1, the light metal ion solution is a Ca 2+ solution, and carbon nanofiber / carbon fiber-confined water enriched with Ca 2+ is obtained.

[0032] Example 4

[0033] In Example 4, which is different from Example 1, the light metal ion solution is a Mg 2+ solution, and carbon nanofiber / carbon fiber-confined water enriched with Mg 2+ is obtained.

[0034] Example 5

[0035] In Example 5, which is different from Example 1, the light metal ion solution is an Al 3+ solution, and carbon nanofiber / carbon fiber-confined water enriched with Al 3+ is obtained.

[0036] Example 6

[0037] In Example 6, which is different from Example 1, the light metal ion solution is a Li + solution, and carbon nanofiber / carbon fiber-confined water enriched with Li + is obtained.

[0038] Test 1

[0039] The physicochemical properties of carbon nanofibers / carbon fibers and the carbon nanofiber / carbon fiber-confined water prepared in Example 1 were characterized by Fourier-transform infrared spectroscopy, and the results are as Figure 1 shown. Compared with carbon nanofibers / carbon fibers, the stretching vibration peak position of -OH in the infrared spectrum of carbon nanofiber / carbon fiber-confined water shows an obvious blue shift (from 3440 cm -1 to 3410 cm -1 ), which indicates that the structure of the -OH bond after water confinement is different from that of bulk water, thus proving that water has been successfully confined.

[0040] Test 2

[0041] Take out the carbon nanofiber / carbon fiber-confined water enriched with light metal ions obtained in Examples 1-6 from the solution after stirring in S2, place it in 10 mL of ultrapure water, stir it at a speed of 400 rpm for 5 min, take out the material, quantitatively analyze the light metal ions in the remaining ultrapure water, and calculate the extraction recovery rate of the carbon nanofiber / carbon fiber-confined water for the light metal ions according to the following formula.

[0042] η = C / C 0 × 100%;

[0043] In the formula, η is the extraction recovery rate, %; C is the content of light metal ions in the remaining ultrapure water, mol / L; C 0 is the content of light metal ions in the light metal ion solution, mol / L.

[0044] Figure 2 For Examples 1-6, the extraction recovery rates of the carbon nanofiber / carbon fiber-confined water for different light metal ions are shown. The results show that the carbon nanofiber / carbon fiber-confined water has high extraction recovery rates for Na + , K + , Ca 2+ , Mg 2+ , Al 3+ , Li + in the light metal ion solution, and they are all ≥ 25%.

[0045] Therefore, the present invention adopts the above method for enriching light metal ions in the carbon nanofiber / carbon fiber nano-confined pores, uses carbon nanofiber / carbon fiber as the confined fluid carrier, and uses ultrapure water, methanol or n-hexane as the extractant. Without introducing chelating agents, it is both green and environmentally friendly and speeds up the mass transfer rate, thus achieving high enrichment of light metal ions in water.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended 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 they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for enriching light metal ions in carbon nanofiber / carbon fiber nanoconfined channels, characterized in that: The following steps are involved: S1. Preparation of carbon nanofiber / carbon fiber confined materials; S2. Place the carbon nanofiber / carbon fiber confined material obtained in S1 in a light metal ion solution and stir.

2. The method for enriching light metal ions in carbon nanofiber / carbon fiber nanoconfined channels according to claim 1, characterized in that: The specific steps of S1 are: spread the carbon nanofiber / carbon fiber flat between two pieces of filter paper, then place it in a Buchner funnel, slowly add the confining solvent for suction filtration, and after the carbon nanofiber / carbon fiber is wetted, stop the suction filtration and take out the carbon nanofiber / carbon fiber confined material.

3. The method for enriching light metal ions in carbon nanofiber / carbon fiber nanoconfined channels according to claim 2, characterized in that: The confined solvent is one of ultrapure water, methanol, and n-hexane.

4. The method for enriching light metal ions in carbon nanofiber / carbon fiber nanoconfined channels according to claim 2, characterized in that: The ratio of confined solvent to carbon nanofiber / carbon fiber in the confined material is: 1 mg carbon nanofiber / carbon fiber corresponds to 2.86-5.72 μL confined solvent.

5. The method for enriching light metal ions in carbon nanofiber / carbon fiber nanoconfined channels according to claim 1, characterized in that: The pH value of the light metal ion solution is 3-9.

6. The method for enriching light metal ions in carbon nanofiber / carbon fiber nanoconfined channels according to claim 1, characterized in that: The light metal ion in the light metal ion solution is Na + , K + , Ca 2+ Mg 2+ 、Al 3+ , Li + One of them.

7. The method for enriching light metal ions in carbon nanofiber / carbon fiber nanoconfined channels according to claim 1, characterized in that: The stirring speed is 400-800 rpm / min, and the stirring time is 1-7 min.

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