Search

CN-117065580-B - Carbon nanofiber polymer cation selective membrane, preparation method and application

CN117065580BCN 117065580 BCN117065580 BCN 117065580BCN-117065580-B

Abstract

The invention belongs to the field of selective membranes, and particularly relates to a carbon nanofiber polymer cation selective membrane, a preparation method and application thereof. The carbon nanofiber polymer cation selective membrane has a compact three-dimensional porous structure and higher surface charge density. The carbon nanofiber polymer cation selective membrane has excellent ion flux and ion selectivity in reverse electrodialysis salt-tolerance energy conversion applications. The method can be applied to a salt difference power generation system, and can obtain high-performance salt difference energy conversion under the environments of electrolyte solutions with different salinity gradients and different pH values.

Inventors

  • SUI XIN
  • Hao Jinlin
  • MA SHUHUI
  • HOU YUSHUANG
  • Lin Cuncai
  • ZHAO JIAWEI

Assignees

  • 青岛大学

Dates

Publication Date
20260512
Application Date
20230901

Claims (10)

  1. 1. The preparation method of the carbon nanofiber polymer cation selective membrane is characterized by comprising the following steps of: s1, adding a solution containing DA, PSSNa, cuSO 4、 H 2 O 2 into a Tris-HCl buffer solution serving as a base solution to form a mixed solution; And S2, vertically placing the graphene@carbon nanofiber subjected to oxidation treatment into the mixed solution for in-situ polymerization, and uniformly filling PDA and PSSNa into a three-dimensional gap of the graphene@carbon nanofiber to obtain the carbon nanofiber polymer cation selective membrane.
  2. 2. The method according to claim 1, wherein the Tris-HCl buffer has a pH of 8.5 and a concentration of 50 mmol/L.
  3. 3. The method according to claim 2, wherein the DA, PSSNa, cuSO 4、 H 2 O 2 is provided in a concentration of 2mg/mL, 5mmol/mL, 19.6mmol/mL, respectively.
  4. 4. The preparation method of the graphene@carbon nanofiber according to claim 2, wherein the graphene@carbon nanofiber is prepared by a traditional electrostatic spinning process, vertical graphene sheets are grown in situ by treating 30-480 min through a chemical vapor deposition method after carbonization in ammonia gas, and the graphene@carbon nanofiber is obtained by oxidizing treatment for 1-10 min through a plasma cleaning machine.
  5. 5. The method of claim 2, wherein the in situ polymerization temperature in step S2 is 25 ℃.
  6. 6. The carbon nanofiber polymer cation selective membrane obtained by the preparation method according to any one of claims 1 to 5, wherein graphene oxide@carbon nanofiber with a compact three-dimensional porous structure is uniformly filled with PDA and PSSNa through in-situ polymerization in a gap of the graphene oxide@carbon nanofiber.
  7. 7. The use of the carbon nanofiber polymer cation selective membrane of claim 6 in salt differential energy power generation.
  8. 8. The use according to claim 7, wherein the method of application is that the carbon nanofiber polymer cation selective membrane is placed between a high-concentration salt solution and a low-concentration salt solution, ag/AgCl electrodes are respectively arranged in the high-concentration salt solution and the low-concentration salt solution, and as the cation selective membrane is negatively charged, when anions and cations in the high-concentration salt solution have a tendency to migrate to the low-concentration salt solution under the drive of a salt difference, the cation selective membrane allows cations to pass, and blocks the migration of anions, thereby generating directional movement of charges, namely generating current, and realizing the conversion of the salt difference energy to electric energy.
  9. 9. The use according to claim 8, wherein the molar concentration ratio of the low concentration salt solution to the high concentration salt solution is 0.000001:0.00001-1.
  10. 10. The use according to claim 8, wherein the high-concentration salt solution and the low-concentration salt solution are any one of potassium chloride solution, sodium chloride solution, lithium chloride solution, calcium chloride solution and magnesium chloride solution, and the salt types of the high-concentration salt solution and the low-concentration salt solution are identical.

Description

Carbon nanofiber polymer cation selective membrane, preparation method and application Technical Field The invention belongs to the field of selective membranes, and particularly relates to a carbon nanofiber polymer cation selective membrane, a preparation method and application thereof. Background Many countries around the world are driving the development of renewable energy harvesting technology, where Reverse Electrodialysis (RED) technology can directly convert the osmotic energy present at the sea and river junction into electrical energy. Ion selective membranes are one of the most important components in RED systems, and in general, ideal ion selective membranes should have high output power density, excellent stability, and sufficient mechanical strength. In recent years, a large number of novel membranes have been developed that convert osmotic forces. However, some of these films are difficult to manufacture on a large scale, even though this can be achieved at lower unit costs. In addition, problems such as high porosity, high mechanical strength, and high surface charge density need to be solved. And, the stability of the ion-selective membrane should be tested in practical applications of osmotic energy. Nanofluidic systems of different structures and properties are used for energy conversion. Nanofluidic channels are generally classified into one-dimensional (1D) nanopore channels, two-dimensional (2D) ion selective membranes, three-dimensional (3D) fluidic systems, and hybrid nanofluidic systems. Although the shape and size of the one-dimensional nano pore canal (such as molybdenum disulfide pore canal) can be designed arbitrarily, the practical application is limited due to the high internal resistance, low porosity and high preparation cost. In addition, 2D ion selective membranes (e.g., graphene oxide membranes) typically form continuous ion channels by stacking 2D nanoplatelets, and they have important potential in applications where osmotic energy is available. However, large-area preparation of two-dimensional material membranes by vacuum filtration is challenging. In addition, the mixed nanofluidic system generally has high rectifying effect and high energy acquisition potential, but has weaker interface binding force and poorer stability. Due to the unique structure of 3D nanofluidic systems, 3D ion channels have attracted considerable interest in salt-differential power generation. Their three-dimensional structure can provide a richer ion channel and significantly shorten the ion transport path, thereby achieving higher ion conductance. Ion selective membranes based on carbon nanomaterials have been demonstrated to significantly improve their permeability and energy conversion properties, while Carbon Nanofiber (CNF) membranes are excellent choices due to their inherent three-dimensional pore structure and feasibility of mass production. According to debye's theory, reasonable channel sizes and high surface charge densities formed by dense three-dimensional network structures will more precisely regulate ion transport. However, the CNF film prepared by common electrospinning has the defects of large pores, low surface charge density, poor hydrophobicity and the like. Therefore, there is an urgent need to develop an ion selective membrane with high porosity, high surface charge density, high mechanical strength, and high salt-poor energy conversion efficiency. The present invention proposes a carbon nanofiber polymer cation selective membrane to overcome the above drawbacks. Disclosure of Invention The invention aims to provide a carbon nanofiber polymer cation selective membrane, a preparation method and application thereof, in particular to a novel cation selective membrane based on a three-dimensional porous structure of a carbon nanofiber polymer, which has excellent stability and is easy to realize conversion from salt difference energy to electric energy. The technical scheme for solving the technical problems is as follows: In a first aspect of the present invention, there is provided a method for preparing a carbon nanofiber polymer cation selective membrane, comprising the steps of: s1, adding a solution containing DA, PSSNa, cuSO 4、H2O2 into a Tris-HCl buffer solution serving as a base solution to form a mixed solution; And S2, vertically placing the graphene@carbon nanofiber subjected to oxidation treatment into the mixed solution for in-situ polymerization, and uniformly filling PDA and PSSNa into a three-dimensional gap of the graphene@carbon nanofiber to obtain the carbon nanofiber polymer cation selective membrane with the three-dimensional porous structure. As a preferred embodiment of the present invention, the Tris-HCl buffer has a pH of 8.5 and a concentration of 50mmol/L. As a preferable technical scheme of the invention, the concentration of DA, PSSNa, cuSO 4、H2O2 is respectively 2mg/mL, 5mmol/mL and 19.6mmol/mL. According to the preferable technical scheme, th