Porous fixed bed electrode of non-metal electro-adsorption device and preparation method of porous fixed bed electrode

Abstract

The invention relates to a porous fixed bed electrode of a non-metal electro-adsorption device and a preparation method of the porous fixed bed electrode. The porous fixed bed electrode comprises the following components in percentage by mass: 70-95% of a non-metallic material and 5-30% of a polymer. The preparation method comprises the following steps: uniformly mixing the non-metallic material and the polymer which are weighed according to a design ratio, and carrying out high-temperature pyrolysis under the protection of oxygen deficiency or inert gas. The electrode has a complex microporous structure, high conductivity and high stability, is suitable for an electro-adsorption device, and can be used as an electrode and an electrolyte or concentrated / fresh water channel. The porous fixed bed electrode solves the problems that a traditional electrode is low in efficiency, prone to blockage and the like, the electric conduction and dynamic performance of the fixed bed electrode is improved, and the working efficiency and the electrode utilization rate of an electro-adsorption device can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a porous fixed bed electrode of a non-metallic electric adsorption device and a preparation method thereof. Background Art

[0002] Capacitive Deionization (CDI) is an efficient water treatment technology that uses the double-layer effect on the electrode surface to adsorb and remove ions in water, thereby achieving water purification and desalination. In recent years, with the global emphasis on water resource protection and sustainable development, electrosorption technology has developed rapidly, especially in the fields of seawater desalination and wastewater treatment, showing great application potential.

[0003] Although electrosorption technology has shown many advantages, it still faces some challenges in practical applications, especially the selection and design of electrode materials. The electrode materials used in traditional electrosorption devices are mainly divided into three types: bulk solid electrodes, flow electrodes and fixed bed electrodes. Bulk solid electrodes are usually made of highly conductive materials, such as graphite or metal-based composites, which have good mechanical strength and conductivity, but due to the lack of sufficient pore structure inside, the ion transmission rate is slow, which in turn affects the working efficiency and electrode utilization of the electrode. In addition, due to the small specific surface area of ​​bulk solid electrodes, their adsorption capacity is limited. The flow electrode is to suspend the electrode powder in the solution and realize the adsorption and removal of ions through the flow of the solution. The flow electrode can provide a larger surface area, thereby improving the adsorption efficiency. However, it has high requirements for the electrode powder, needs to maintain a slurry state, and is prone to clogging problems in actual operation. In addition, the electrode powder in the flow electrode may settle during long-term operation, affecting the treatment efficiency. Fixed bed electrodes allow liquid to flow through them, greatly improving the kinetic performance of the electrode. Compared with bulk solid electrodes, fixed bed electrodes have a larger specific surface area and can improve the adsorption efficiency. However, fixed bed electrodes still have poor performance when treating high-concentration water bodies, especially when treating wastewater containing high concentrations of salt, where their adsorption capacity is limited, and the stability and life of the electrodes are also affected in high-salinity environments. Therefore, it is urgent to develop electrodes with high conductivity, high kinetic performance, and high stability to meet the actual water treatment needs of complex water quality and high concentration. Summary of the invention

[0004] The object of the present invention is to provide a non-metallic porous fixed bed electrode to solve the problems existing in the above-mentioned background technology, improve the conductivity, dynamic performance and stability of the fixed bed electrode, and enable it to be applied to an electric adsorption device.

[0005] The specific technical solution adopted by the present invention is as follows: a porous fixed bed electrode of a non-metallic electrosorption device, wherein the mass percentages of the components of the porous fixed bed electrode are: non-metallic material: 70-95wt% and polymer 5-30wt%.

[0006] Furthermore, the non-metallic material is one or more of activated carbon, carbon nanotubes, graphene, and non-metallic element-doped carbon materials;

[0007] The polymer is one or more of coal tar pitch, polypyrrole (PPy), polythiophene (PT), polyaniline (PANI), polyvinylcarbazole (PVK), polyacetylene (PA), and polyparaphenylene (PPP).

[0008] Furthermore, the non-metallic element doped carbon material is one or more of nitrogen-doped carbon nanotubes and phosphorus-doped carbon nanofibers.

[0009] Another object of the present invention is to provide a method for preparing the above-mentioned porous fixed bed electrode, which method specifically comprises the following steps:

[0010] S1) weighing the non-metallic material and the polymer according to the designed ratio, mixing them evenly to obtain a mixed material;

[0011] S2) placing the mixed material obtained in S1) into a mold and flattening it with a flat plate;

[0012] S3) placing the mold in a high temperature environment for pyrolysis treatment under the protection of oxygen deficiency or inert gas, and forming a porous fixed bed electrode after cooling.

[0013] Furthermore, the shape of the mold in S2) is a flat rectangular parallelepiped, a cylinder or other suitable shapes.

[0014] Furthermore, the parameters of the pyrolysis treatment in S3) are: a temperature of 400 to 2500° C. and a time of 1 to 5 hours.

[0015] Furthermore, the inert gas in S3) is nitrogen or argon.

[0016] Furthermore, the porous fixed bed electrode has a microporous structure with a pore volume of 0.3-2 cm 3 / g, with an average pore size of 0.5-3nm; and a specific surface area greater than 500m 2 / g; conductivity is greater than 10S / m.

[0017] A porous fixed bed electrode prepared by the above method is used as an electrode and an electrolyte or concentrated / fresh water channel of an electric adsorption device.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The porous fixed bed electrode provided by the present invention has a complex microporous structure, which increases the specific surface area of ​​the electrode, and is beneficial to improving the adsorption capacity and charge storage capacity of the electrode; it has high conductivity, so that the electrode can work at a lower voltage, reducing energy consumption; it has high stability, which ensures the performance stability of the electrode during long-term operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flowchart of a method for preparing a porous fixed bed electrode of a non-metallic electrosorption device. DETAILED DESCRIPTION

[0021] The present invention is further described and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0022] like Figure 1 As shown, the present invention provides a method for preparing a porous fixed bed electrode of a non-metallic electrosorption device, and the specific steps are as follows:

[0023] -Mix the non-metallic granular or powdered material with coal tar or other polymer in a certain proportion;

[0024] -Put the mixture into a flat rectangular or other shaped mold and flatten it with a flat plate;

[0025] - Under the protection of oxygen deficiency or inert gas, the mold is placed in a high temperature environment for pyrolysis treatment, and the non-metallic porous fixed bed electrode is formed after cooling.

[0026] Preferably, the non-metallic particles or powder materials are one or more of activated carbon, carbon nanotubes, graphene, non-metallic element-doped carbon materials and the like.

[0027] Preferably, the non-metallic element doped carbon material is selected from one or more of nitrogen-doped carbon nanotubes, phosphorus-doped carbon nanofibers and the like.

[0028] Preferably, the mold is in the shape of a flat cuboid, a cylinder or other suitable shapes.

[0029] Preferably, the temperature of the pyrolysis treatment is 400 to 2500 degrees Celsius.

[0030] Preferably, the inert gas is selected from nitrogen and argon.

[0031] Preferably, the pyrolysis treatment time is 1-5 hours.

[0032] Preferably, the electrode has a complex microporous structure, high conductivity and high stability.

[0033] Preferably, the specific surface area of ​​the electrode is greater than 500 m 2 / g.

[0034] Preferably, the conductivity of the electrode is greater than 10 S / m.

[0035] The electrode is suitable for an electric adsorption device and can be used as an electrode and an electrolyte or concentrated / fresh water channel.

[0036] Example 1

[0037] The preparation materials used in this example include 20g of activated carbon particles, 8g of nitrogen-doped carbon nanotubes, 2g of graphene, and 10g of coal tar pitch. The specific preparation steps are as follows:

[0038] Step 1: Mix the above materials evenly according to the weight ratio;

[0039] Step 2: Place the mixture into a flat rectangular mold with a size of 10cm×10cm×2cm and flatten the material in the mold with a flat plate;

[0040] Step 3: Under nitrogen protection, place the mold in a tube furnace, set the temperature to 1000°C, the pyrolysis time to 2 hours, and the initial heating rate to 5°C / min.

[0041] Step 4: After the pyrolysis is completed, the mold is naturally cooled to room temperature and the formed non-metallic porous fixed bed electrode is taken out.

[0042] The final porous fixed bed electrode material prepared in this embodiment has a rich microporous structure and a specific surface area of ​​735m 2 / g. The conductivity of the electrode measured by the four-probe method was 15S / m, indicating that the electrode has good conductivity. The electrode was tested for adsorption capacity in an electric adsorption device. The results showed that the maximum adsorption capacity of the electrode when treating salt water was 20mg / g, and it could run stably and continuously for 100 hours. The results showed that the electrode has good stability.

[0043] Example 2

[0044] The materials used in this example include 15g of graphene, 5g of phosphorus-doped carbon nanofibers, and 10g of polypyrrole (PPy). The specific preparation steps are as follows:

[0045] Step 1: Mix the above materials evenly according to the weight ratio;

[0046] Step 2: Place the mixture into a flat rectangular mold with a size of 10cm×10cm×2cm and flatten the material in the mold with a flat plate;

[0047] Step 3: Under nitrogen protection, place the mold in a tube furnace, set the temperature to 1200°C, pyrolysis time to 3 hours, and the initial heating rate to 5°C / min;

[0048] Step 4: After the pyrolysis is completed, the mold is naturally cooled to room temperature and the formed non-metallic porous fixed bed electrode is taken out.

[0049] The final porous fixed bed electrode material prepared in this embodiment has a rich microporous structure and a specific surface area of ​​680 m 2 / g. The conductivity of the electrode measured by the four-probe method was 12S / m, indicating that the electrode has good conductivity. The electrode was tested for adsorption capacity in an electric adsorption device. The results showed that the maximum adsorption capacity of the electrode when treating salt water was 18mg / g, and it could run stably and continuously for 100 hours. The results showed that the electrode has good stability.

[0050] Example 3

[0051] The preparation materials used in this example include 20g of carbon nanotubes, 10g of activated carbon particles, and 10g of polythiophene (PT). The specific preparation steps are as follows:

[0052] Step 1: Mix the above materials evenly according to the weight ratio;

[0053] Step 2: Place the mixture into a flat rectangular mold with a size of 10cm×10cm×2cm and flatten the material in the mold with a flat plate;

[0054] Step 3: Under nitrogen protection, place the mold in a tube furnace, set the temperature to 800°C, pyrolysis time to 4 hours, and the initial heating rate to 5°C / min;

[0055] Step 4: After the pyrolysis is completed, the mold is naturally cooled to room temperature and the formed non-metallic porous fixed bed electrode is taken out.

[0056] The final porous fixed bed electrode material prepared in this embodiment has a rich microporous structure and a specific surface area of ​​650m 2 / g. The conductivity of the electrode measured by the four-probe method was 11S / m, indicating that the electrode has good conductivity. The electrode was tested for adsorption capacity in an electric adsorption device. The results showed that the maximum adsorption capacity of the electrode when treating salt water was 16mg / g, and it could run stably and continuously for 100 hours. The results showed that the electrode has good stability.

[0057] The above is a detailed introduction to a porous fixed bed electrode of a non-metallic electrosorption device and its preparation method provided in the embodiment of the present application. The description of the above embodiment is only used to help understand the method and its core idea of ​​the present application; at the same time, for a person skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0058] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0059] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0060] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0061] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A porous fixed bed electrode for a non-metallic electrosorption device, characterized in that: The mass percentages of the components of the porous fixed bed electrode are as follows: non-metallic material: 70-95wt% and polymer: 5-30wt%.

2. The porous fixed bed electrode according to claim 1, characterized in that: The non-metallic material is one or more of activated carbon, carbon nanotubes, graphene, and non-metallic element-doped carbon materials; The polymer is one or more of coal tar pitch, polypyrrole, polythiophene, polyaniline, polyvinyl carbazole, polyacetylene and polyparaphenylene.

3. The porous fixed bed electrode according to claim 2, characterized in that: The non-metallic element doped carbon material is one or more of nitrogen-doped carbon nanotubes and phosphorus-doped carbon nanofibers.

4. A method for preparing a porous fixed bed electrode as claimed in any one of claims 1 to 3, characterized in that: The method specifically comprises the following steps: S1) weighing the non-metallic material and the polymer according to the designed ratio, mixing them evenly to obtain a mixed material; S2) placing the mixed material obtained in S1) into a mold and flattening it with a flat plate; S3) placing the mold in a high temperature environment for pyrolysis treatment under the protection of oxygen deficiency or inert gas, and forming a porous fixed bed electrode after cooling.

5. The method according to claim 4, characterized in that The shape of the mold in S2) is a flat rectangular parallelepiped, a cylinder or other suitable shapes.

6. The method according to claim 4, characterized in that The parameters of the pyrolysis treatment in S3) are: a temperature of 400-2500° C. and a time of 1-5 hours.

7. The method according to claim 4, characterized in that The inert gas in S3) is nitrogen or argon.

8. The method according to claim 4, characterized in that The porous fixed bed electrode has a microporous structure with a pore volume of 0.3-2 cm 3 / g, with an average pore size of 0.5-3nm; and a specific surface area greater than 500m 2 / g; conductivity is greater than 10S / m.

9. A porous fixed bed electrode prepared by the method according to claims 4-8 as an electrode and electrolyte or concentrated / fresh water channel of an electric adsorption device.

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