A general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials

Abstract

This invention discloses a general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials, belonging to the field of water treatment technology. The method includes the following steps: S1, preparing carbon nanofiber / carbon fiber confinement materials; S2, adjusting the pH of a seawater sample, and using a syringe pump to uniformly push the seawater sample through the carbon nanofiber / carbon fiber confinement materials obtained in S1. This invention employs the aforementioned general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials, using carbon nanofiber / carbon fiber as the confinement fluid carrier and ultrapure water, methanol, or n-hexane as the extractant. It eliminates the need for chelating agents, is environmentally friendly, and requires no energy consumption to achieve desalination of Na+ from seawater. + and Cl ‑ Absorption rate up to 82%.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a general method for achieving seawater desalination based on carbon nanofiber / carbon fiber confinement materials. Background Art

[0002] Over the past few decades, with global population growth, expanded agricultural irrigation areas, and improved living standards, freshwater scarcity has become a major challenge threatening sustainable human development. Many countries and regions currently face freshwater shortages. Therefore, developing efficient seawater desalination technologies is crucial.

[0003] Traditional desalination methods are mainly divided into two categories: thermal methods and membrane methods. Compared with thermal methods, membrane methods have attracted much attention due to their advantages such as low energy consumption, low cost, and high water quality. The separation mechanism of membrane methods is mainly based on two principles: the molecular sieve effect of neutral solutes and the Donnan effect of charged solutes. Carbon-based materials, as typical porous membranes, have advantages such as good conductivity and suitable pore size distribution, and are therefore often used as electroadsorption electrodes. However, their complex operation process and time-consuming and labor-intensive characteristics severely limit their widespread application in the field of seawater desalination.

[0004] In recent years, liquid-phase nanoextraction technology has provided a new research direction for seawater desalination. This technology is based on the size and interface effects of nanoconfined spaces, using multidimensional channels as confined fluid extraction units. Thermodynamic and kinetic studies have shown that this technology has advantages such as spontaneous process, rapid mass transfer, and high throughput. Therefore, liquid-phase nanoextraction technology is expected to become a significant breakthrough in developing low-energy, rapid desalination methods, providing new ideas for the development of seawater desalination technology. Summary of the Invention

[0005] The purpose of this invention is to provide a general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials. Using carbon nanofiber / carbon fiber as the confinement fluid carrier and ultrapure water, methanol, or n-hexane as the extractant, this method eliminates the need for chelating agents, is environmentally friendly, and requires no energy consumption to desalinate Na+ from seawater. + and Cl - Absorption rate up to 82%.

[0006] To achieve the above objectives, this invention provides a general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials, comprising the following steps:

[0007] S1. Preparation of carbon nanofiber / carbon fiber confined materials;

[0008] S2. Adjust the pH of the seawater sample and use a syringe pump to push the seawater sample through the carbon nanofiber / carbon fiber confinement material obtained in S1 at a constant speed.

[0009] Preferably, the specific steps of S1 are as follows: uniformly filling carbon nanofibers / carbon fibers into a polyethersulfone filter membrane, loading the filled filter membrane onto a syringe, and using a syringe pump to uniformly push the confining solvent into the filter membrane to obtain a carbon nanofiber / carbon fiber confined material.

[0010] Preferably, in S1, the confining solvent is one of ultrapure water, methanol, and n-hexane.

[0011] Preferably, in S1, the membrane pass rate of the confined solvent is 1-10 mL / min.

[0012] Preferably, in S1, the ratio of confinement solvent to carbon nanofiber / carbon fiber in the carbon nanofiber / carbon fiber confinement material is: 1 mg of carbon nanofiber / carbon fiber corresponds to 1.43-5.72 μL of confinement solvent.

[0013] Preferably, in S2, the pH value of the seawater sample is adjusted to 3-9.

[0014] Preferably, the seawater sample in S2 passes through the membrane at a rate of 1-10 mL / min.

[0015] Therefore, the present invention employs the above-mentioned general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials, which has the following beneficial effects:

[0016] (1) Using carbon nanofibers / carbon fibers as confined fluid carriers and ultrapure water, methanol or n-hexane as extractants, no chelating agents are required, making it green and environmentally friendly.

[0017] (2) The water confinement of carbon nanofibers / carbon fibers not only affects the hydrogen bond configuration and diffusion mass transfer rate of water, but also accelerates the ion mass transfer rate.

[0018] (3) Absorption of Na from seawater by confining water using carbon nanofibers / carbon fibers + and Cl - This facilitates the full interaction between confined water and target ions, enabling efficient removal of Na+ from seawater without consuming energy. + and Cl - .

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This invention relates to a general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials, which utilizes different confinement fluid carriers and confinement solvents to treat Na+. + and Cl - A schematic diagram showing the absorption efficiency results. Detailed Implementation

[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 or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] Main instruments and reagents used: A PXSJ-226T ion-selective electrode (ISE, Leici, China) was used to detect Na. + and Cl - Concentration; XFP01-B syringe pump (Suzhou Xunfei Co., Ltd., China); chromatographic grade methanol (MeOH) and n-hexane (HEX) (Sigma Aldrich).

[0024] Example 1

[0025] A general method for achieving seawater desalination based on carbon nanofiber / carbon fiber confinement materials includes the following steps:

[0026] S1. Preparation of carbon nanofiber / carbon fiber confined water: 0.35g of carbon nanofiber / carbon fiber was uniformly filled into a polyethersulfone filter membrane with a pore size of 0.22μm. The filled filter membrane was loaded onto a syringe, and ultrapure water was uniformly pushed through the filter membrane at a rate of 3mL / min using a syringe pump to obtain carbon nanofiber / carbon fiber confined water. The ratio of ultrapure water to carbon nanofiber / carbon fiber in the carbon nanofiber / carbon fiber confined water was: 1mg of carbon nanofiber / carbon fiber corresponds to 4.29μL of ultrapure water.

[0027] S2. The original pH value of the seawater sample is 8. 5 mL of seawater sample is pushed through the carbon nanofiber / carbon fiber confined water obtained in S1 at a constant speed of 3 mL / min using a syringe pump.

[0028] Example 2

[0029] A general method for achieving seawater desalination based on carbon nanofiber / carbon fiber confinement materials includes the following steps:

[0030] S1. Preparation of carbon nanofiber / carbon fiber confined methanol: 0.35g of carbon nanofiber / carbon fiber was uniformly filled into a polyethersulfone filter membrane with a pore size of 0.22μm. The filled filter membrane was loaded onto a syringe, and methanol was uniformly pushed into the filter membrane at a rate of 3mL / min using a syringe pump to obtain carbon nanofiber / carbon fiber confined methanol. The ratio of methanol to carbon nanofiber / carbon fiber in the carbon nanofiber / carbon fiber confined methanol was: 1mg of carbon nanofiber / carbon fiber corresponds to 4.29μL of methanol.

[0031] S2. The original pH value of the seawater sample is 8. Using a syringe pump, 5 mL of seawater sample is pushed through the carbon nanofiber / carbon fiber confined methanol obtained in S1 at a constant speed of 3 mL / min.

[0032] Example 3

[0033] A general method for achieving seawater desalination based on carbon nanofiber / carbon fiber confinement materials includes the following steps:

[0034] S1. Preparation of carbon nanofiber / carbon fiber confined n-hexane: 0.35g of carbon nanofiber / carbon fiber was uniformly filled into a polyethersulfone filter membrane with a pore size of 0.22μm. The filled filter membrane was loaded onto a syringe, and n-hexane was uniformly pushed through the filter membrane at a rate of 3mL / min using a syringe pump to obtain carbon nanofiber / carbon fiber confined n-hexane. The ratio of n-hexane to carbon nanofiber / carbon fiber in the carbon nanofiber / carbon fiber confined n-hexane was: 1mg of carbon nanofiber / carbon fiber corresponds to 4.29μL of n-hexane.

[0035] S2. The original pH value of the seawater sample is 8. Using a syringe pump, 5 mL of the seawater sample is pushed through the carbon nanofiber / carbon fiber confined n-hexane obtained in S1 at a constant speed of 3 mL / min.

[0036] Comparative Example 1

[0037] A general method for seawater desalination based on carbon fiber confinement materials includes the following steps:

[0038] S1. Preparation of carbon fiber confined water: 0.35g of carbon fiber was uniformly filled into a polyethersulfone filter membrane with a pore size of 0.22μm. The filled filter membrane was loaded onto a syringe, and ultrapure water was uniformly pushed through the filter membrane at a rate of 3mL / min using a syringe pump to obtain carbon fiber confined water. The ratio of ultrapure water to carbon fiber in the carbon fiber confined water was: 1mg of carbon fiber corresponds to 4.29μL of ultrapure water.

[0039] S2. The original pH value of the seawater sample is 8. 5 mL of seawater sample is pushed through the carbon fiber confined water obtained in S1 at a constant speed of 3 mL / min using a syringe pump.

[0040] Comparative Example 2

[0041] A general method for seawater desalination based on carbon fiber confinement materials includes the following steps:

[0042] S1. Preparation of carbon fiber-confined methanol: 0.35g of carbon fiber was uniformly filled into a polyethersulfone filter membrane with a pore size of 0.22μm. The filled filter membrane was loaded onto a syringe, and methanol was uniformly pushed into the filter membrane at a rate of 3mL / min using a syringe pump to obtain carbon fiber-confined methanol. The ratio of methanol to carbon fiber in the carbon fiber-confined methanol was: 1mg of carbon fiber corresponds to 4.29μL of methanol.

[0043] S2. The original pH value of the seawater sample is 8. 5 mL of seawater sample is pushed through the carbon fiber-confined methanol obtained in S1 at a constant speed of 3 mL / min using a syringe pump.

[0044] Comparative Example 3

[0045] A general method for seawater desalination based on carbon fiber confinement materials includes the following steps:

[0046] S1. Preparation of carbon fiber-confined n-hexane: 0.35g of carbon fiber was uniformly filled into a polyethersulfone filter membrane with a pore size of 0.22μm. The filled filter membrane was loaded onto a syringe, and n-hexane was uniformly pushed through the filter membrane at a rate of 3mL / min using a syringe pump to obtain carbon fiber-confined n-hexane. The ratio of n-hexane to carbon fiber in the carbon fiber-confined n-hexane was: 1mg of carbon fiber corresponds to 4.29μL of n-hexane.

[0047] S2. The original pH value of the seawater sample is 8. 5 mL of seawater sample is pushed through the carbon fiber-confined n-hexane obtained in S1 at a constant speed of 3 mL / min using a syringe pump.

[0048] The filtrates from seawater samples of Examples 1-3 and Comparative Examples 1-3 were collected, and the Na content in the filtrates was determined. + and Cl - The concentration of Na in seawater samples was calculated using the following formula: (The confinement of water by carbon nanofibers / carbon fibers and the effect of carbon fibers on Na concentration). + and Cl - Absorption rate.

[0049]

[0050] In the formula, η is the absorption rate, %; C is the Na content in the filtrate. + and Cl - Concentration, mol / L; CO is the Na content in the seawater sample. + and Cl - Concentration, mol / L.

[0051] Figure 1 Different confined fluid carriers and confined solvents are used to treat Na + and Cl - A schematic diagram of the absorption efficiency results, from Figure 1It can be seen that carbon nanofiber / carbon fiber confinement materials have a certain effect on Na. + and Cl - The absorption rates of these materials are all higher than those of carbon fiber confinement materials. Based on the "nanoconfinement effect" and the "like dissolves like" principle, when carbon nanofibers / carbon fibers are used as the confinement fluid carrier and ultrapure water as the confinement solvent, the absorption rate of Na+ is significantly higher. + and Cl - It has the highest absorption rate, approximately 82%.

[0052] Therefore, this invention employs the aforementioned general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials. Using carbon nanofiber / carbon fiber as the confinement fluid carrier and ultrapure water, methanol, or n-hexane as the extractant, it eliminates the need for chelating agents, is environmentally friendly, and requires no energy consumption to desalinate Na+ from seawater. + and Cl - Absorption rate up to 82%.

[0053] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials, characterized in that, The following steps are involved: S1. Preparation of carbon nanofiber / carbon fiber confined materials; S2. Adjust the pH of the seawater sample and use a syringe pump to push the seawater sample through the carbon nanofiber / carbon fiber confinement material obtained in S1 at a constant speed. The specific steps of S1 are as follows: uniformly fill carbon nanofibers / carbon fibers into the polyethersulfone filter membrane, load the filled filter membrane onto the syringe, and use the syringe pump to push the confining solvent into the filter membrane at a uniform speed to obtain carbon nanofiber / carbon fiber confining material. In S1, the confining solvent is one of ultrapure water, methanol, and n-hexane; In S1, the ratio of confinement solvent to carbon nanofiber / carbon fiber in the carbon nanofiber / carbon fiber confinement material is: 1 mg of carbon nanofiber / carbon fiber corresponds to 1.43-5.72 μL of confinement solvent.

2. The general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials according to claim 1, characterized in that, In S1, the confined solvent permeate rate is 1-10 mL / min.

3. The general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials according to claim 1, characterized in that, In S2, the pH of the seawater sample is adjusted to 3-9.

4. A general method for seawater desalination based on carbon nanofiber / carbon fiber confinement materials according to claim 1, characterized in that, In S2, the seawater sample passes through the membrane at a rate of 1-10 mL / min.

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