阅读说明：本技术 一种bc基碱性阴离子交换膜及其制备和应用 (BC-based basic anion exchange membrane and preparation and application thereof ) 是由 乔锦丽 郭晓晶 魏群山 邹倩倩 高璐 洪枫 于 2020-04-16 设计创作，主要内容包括：本发明涉及一种BC基碱性阴离子交换膜及其制备和应用,所述交换膜以包括细菌纤维素膜、含季铵基团的水溶性聚合物的组分,通过化学交联获得。本发明提供的BC基碱性阴离子交换复合膜制备方法简单,成本低廉,环境友好,易于规模化应用。(The invention relates to a BC-based basic anion exchange membrane, and preparation and application thereof. The preparation method of the BC-based basic anion exchange composite membrane provided by the invention is simple, low in cost, environment-friendly and easy for large-scale application.)

1. An alkaline anion exchange membrane, characterized in that it is obtained by chemical cross-linking, with a composition comprising a bacterial cellulose membrane, a water-soluble polymer containing quaternary ammonium groups.

2. The alkaline anion exchange membrane of claim 1, wherein the bacterial cellulose membrane is a hydroxyl-containing bacterial cellulose membrane BC.

3. The alkaline anion exchange membrane of claim 1 wherein the water soluble polymer containing quaternary ammonium groups is poly (diallyldimethylammonium chloride) (PDDA); the cross-linking agent used for chemical cross-linking is glutaraldehyde.

4. A method of preparing a basic anion exchange membrane comprising:

(1) soaking a bacterial cellulose membrane containing hydroxyl into a water-soluble polymer solution containing quaternary ammonium groups to obtain a polymer membrane;

(2) and (2) carrying out chemical crosslinking treatment on the polymer membrane in the step (1), and then soaking the polymer membrane in a KOH solution for sealing ion exchange to obtain the alkaline anion exchange membrane.

5. The preparation method according to claim 4, wherein the water-soluble polymer containing quaternary ammonium groups in step (1) is poly (diallyldimethylammonium chloride) (PDDA); the mass percentage of the water-soluble polymer solution containing the quaternary ammonium group is 2.5 wt% -10 wt%.

6. The method according to claim 4, wherein the soaking time in the step (1) is 1 to 24 hours.

7. The method according to claim 4, wherein the chemical crosslinking in the step (2) is: soaking the polymer film into a cross-linking agent solution, and chemically cross-linking for 0.5-2.5 h at room temperature; the chemical crosslinking concentration is 5 wt.% to 25 wt.%, and the crosslinking agent is glutaraldehyde.

8. The preparation method according to claim 4, wherein the molar concentration of the KOH solution is 1-5 mol/L.

9. A basic anion exchange membrane prepared by the method of claim 4.

10. Use of the alkaline anion exchange membrane of claim 1 in an electrochemical energy device.

Technical Field

The invention belongs to CO₂An anion exchange membrane for electrocatalytic conversion and the preparation and application fields thereof, in particular to a BC-based alkaline anion exchange membrane and the preparation and application thereof.

Background

In recent years, CO₂The electrochemical reduction method (ERC) is favored by researchers in the future [ Science Bulletin,64(2019) ] 1890-1895 because it can use renewable energy to drive the conversion of ERC into high-value-added fuel and useful chemicals at room temperature and normal pressure]. Over the past decades, more research has been directed towards developing novel and efficient electrode catalysts to enhance CO₂Electrochemical reduction performance. However, as CO₂The core of electrochemical reduction and the diaphragm also play very important roles, and the electrochemical reduction device not only can effectively separate electrolytes of the anode and the cathode of an electrolytic cell, but also can regulate the ion flow between the two electrodes while inhibiting the product crossing. At present in CO₂Two types of membranes can be used in electrochemical reduction H-cells, one being an anion exchange membrane (e.g., OH)^-) And the other is a cation exchange membrane (e.g., a Nafion membrane). Nafion membranes due to their higher conductivity (0.1S cm)^-1About) and excellent mechanical properties for wide application to CO₂Electrochemical reduction, however, is expensive and complicated. Anion exchange membranes have been popular in recent years as electrochemical membranes due to their low cost and low formic acid permeability [ Catalysis Today,318(2018)32-38]。

Among anion exchange membranes, they are classified into Alkaline Anion Exchange Membranes (AAEMs) and alkaline gel electrolytes (AGPEs), which integrate the advantages of solid electrolytes and liquid electrolytes, and have relatively high ionic conductivity. However, AGPEs have poor dimensional and mechanical stability, resulting in insufficient physical protection between electrodes, and further in ohmic polarization [ ACS Appl MaterInterfaces,11(2019)6881-]. AAEMs are very suitable for CO as a diaphragm capable of transporting hydroxide ions and preventing product crossing between two electrodes₂Electrochemical reduction H-type electrolytic cell [ J.CO ]₂Utilization,23(2018)152-158]. However, generally for CO₂Electrochemical reduction of AAEMs of H-cells with Polyetherimides (PEI), poly (I)Arylene Ether Sulfones (PAES), biphenyl polyether ketones (PPEK), and the like as the main polymer backbone [ phys. Sep.&Purification Technol.，94(2012)131–137]The price is high, the preparation is complex and the environment is not protected, so the cheap, simple and green alkaline anion exchange membrane is developed to be used as CO₂Electrochemical reduction of H-type cell membranes is more challenging.

CN102294183A discloses a multi-quaternary ammonium salt type anion exchange membrane and a preparation method thereof, but the preparation cost is relatively high, and the multi-quaternary ammonium salt type anion exchange membrane is not environment-friendly and cannot be biodegraded.

Disclosure of Invention

The invention aims to solve the technical problem of providing a BC-based alkaline anion exchange membrane and preparation and application thereof, and overcoming the defects of complex preparation, high cost and poor environmental protection in the prior art.A BC membrane of the invention is an alkaline anion exchange membrane taking a bacterial cellulose BC membrane as a matrix, and comprises the components of a BC membrane containing hydroxyl and a water-soluble polymer containing quaternary ammonium groups, wherein the BC-based alkaline anion exchange membrane is prepared by a simple impregnation method; through chemical cross-linking and finally soaking in KOH solution for ion exchange.

The invention relates to a basic anion exchange membrane which is obtained by chemically crosslinking components comprising a bacterial cellulose membrane and a water-soluble polymer containing quaternary ammonium groups.

The bacterial cellulose membrane is a hydroxyl-containing bacterial cellulose membrane BC (strain number DHU-ATCC-1 is used).

The bacterial cellulose membrane is cultured by taking glucose as a substrate.

Further, the bacterial cellulose membrane BC containing a hydroxyl group is obtained by culturing bacteria using glucose, yeast extract, and tryptone as a substrate.

Further, the bacterial cellulose membrane is prepared by dissolving 5g of glucose, 0.5g of tryptone and 0.3g of yeast extract powder in 100m L of deionized water, stirring, adjusting the pH value to 5.0-6.0, uniformly sealing, packaging in 5 culture dishes, then carrying out autoclaving at 115 ℃ for 30min, inoculating 1m L of DHU-ATCC-1 bacterial solution into each culture dish, sealing again, standing in a constant-temperature incubator at 30 ℃, carrying out constant-temperature culture until the culture medium is completely absorbed, and placing in 1 wt% of NaOH solution for 2 days to prepare the bacterial cellulose membrane BC.

The water-soluble polymer containing quaternary ammonium groups is poly (diallyldimethylammonium chloride) (PDDA); the cross-linking agent used for chemical cross-linking is glutaraldehyde.

The invention discloses a preparation method of a basic anion exchange membrane, which comprises the following steps:

(1) soaking a bacterial cellulose membrane containing hydroxyl into a water-soluble polymer solution containing quaternary ammonium groups to obtain a polymer membrane;

(2) and (2) carrying out chemical crosslinking treatment on the polymer membrane in the step (1), and then soaking the polymer membrane in a KOH solution for sealing ion exchange to obtain the alkaline anion exchange membrane.

The preferred mode of the above preparation method is as follows:

the water-soluble polymer containing quaternary ammonium groups in the step (1) is poly (diallyldimethylammonium chloride) (PDDA); the mass percentage of the water-soluble polymer solution containing the quaternary ammonium group is 2.5 wt% -10 wt%.

The soaking time in the step (1) is 1-24 h.

The chemical crosslinking in the step (2) is as follows: soaking the polymer film into a cross-linking agent solution, and chemically cross-linking for 0.5-2.5 h at room temperature; the chemical crosslinking concentration is 5 wt.% to 25 wt.%, and the crosslinking agent is glutaraldehyde.

The molar concentration of the KOH solution is 1-5 mol/L.

The invention relates to a basic anion exchange membrane prepared by the method.

The invention provides an application of the alkaline anion exchange membrane in an electrochemical energy device, wherein the electrochemical energy device is H₂/O₂Any one of a fuel cell, a metal-air battery, and a supercapacitor. In particular to a diaphragm material used in electrochemical reduction of carbon dioxide.

The alkaline anion exchange membrane is used for CO₂Electrochemical reduction of the H-cell membrane.

The invention provides a brand-new preparation method which comprises the following steps: applying bacterial cellulose membrane commonly used in the fields of biomedicine and the like to CO₂In the field of electrochemical reduction, the hyperfine network structure of a Bacterial Cellulose (BC) membrane is used for directly constructing the skeleton structure of the alkaline anion exchange membrane, and the method is simple and environment-friendly.

Advantageous effects

(1) The BC membrane is adopted as the basic anion exchange membrane matrix, and the preparation is simple and environment-friendly, and is biodegradable and easy to operate.

(2) The alkaline anion exchange composite membrane has high ionic conductivity, and the room temperature can reach 0.024S/cm.

(3) The basic anion exchange composite membrane can be directly used for CO₂Electrochemical reduction with good CO₂Electrochemical reduction performance, best for the example 2 membrane, was shown by high current density (31.59mA cm)^-2) And high formic acid faradaic efficiency (50.84%).

Drawings

FIG. 1 is an SEM image of a BC-PDDA-2 basic anion exchange membrane;

FIG. 2(a) is a graph comparing the conductivity and water content of BC-PDDA alkaline anion exchange membranes prepared from examples 1-4 with different mass percent of PDDA; (b) is a comparison graph of the conductivity and the water content of the BC-PDDA-2 basic anion-exchange membrane prepared in example 5 after different chemical crosslinking time; (c) is a comparison graph of the conductivity and the water content of the BC-PDDA-2 alkaline anion-exchange membrane prepared in example 6 after different chemical crosslinking concentrations; (d) is a graph comparing the conductivity and water content of the BC-PDDA-2 basic anion-exchange membrane prepared in example 7 after being subjected to different KOH concentrations;

FIG. 3 shows the basic anion-exchange membrane BC-PDDA prepared in examples 1-4 in CO₂0.5M KHCO at saturation₃Linear sweep voltammetry curves in solution;

FIG. 4 shows the basic anion-exchange membrane BC-PDDA prepared in examples 1-4 in CO₂0.5M KHCO at saturation₃Electrolyze in solution at-0.96V vs. RHE electrolytic potential 1h formic acid faradic efficiency.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

The manufacturer and specifications of the reagents used in the examples of the invention are shown in the following table: