CN-122025441-A - Iron-doped sludge-based biochar supported electrode material and preparation method thereof

Abstract

The invention provides an iron-doped sludge-based biochar supported electrode material and a preparation method thereof, and belongs to the technical field of electrode material preparation. According to the invention, foam nickel is used as a substrate, the mixture of modified sludge-based biochar and modified Fe 3 O 4 powder, a conductive agent, a binder and a solvent are mixed to prepare electrode slurry, the electrode slurry is coated on the foam nickel substrate, and after high-temperature heat treatment, the firm loading of the sludge peat on the surface of the foam nickel is realized, so that the conductivity and the structural stability of the composite electrode material are obviously improved. The electrode material prepared by the invention has the characteristics of strong electricity storage capacity, high charge transfer efficiency, high energy density, obvious extension of the service life of the electrode and the like. The invention can also improve the resource utilization rate of the sludge solid waste, and has the advantages of environmental protection, low cost and good economic benefit.

Inventors

• WEN PENGLI
• CUI YOUWEI
• GE ZHENG

Assignees

• 北京工业大学

Dates

Publication Date

20260512

Application Date

20260328

Claims (9)

1. 1. The preparation method of the iron-doped sludge-based biochar supported electrode material is characterized by comprising the following steps of: (1) Sequentially dehydrating, drying and pyrolyzing the collected sludge, collecting sludge-based biochar, and crushing and sieving the sludge-based biochar to obtain sludge-based biochar powder; (2) Placing the sludge-based biochar powder into yttrium trichloride solution, and stirring for a certain time to obtain a dispersion liquid containing sludge-based biochar; (3) Adding urea into the dispersion liquid containing the sludge-based biochar to obtain a mixed liquid, wherein the concentration of the urea in the mixed liquid is 0.5 mol/L, transferring the mixed liquid into a high-pressure reaction kettle, carrying out hydrothermal reaction for 6-12 hours at 120-180 ℃, centrifugally separating, collecting solids, and drying the solids to obtain modified sludge-based biochar powder for later use; (4) Placing Fe 3 O 4 powder in absolute ethyl alcohol, carrying out ultrasonic treatment until the Fe 3 O 4 powder is uniformly dispersed, then adding bis [3- (triethoxysilyl) propyl ] amine into a system, carrying out heating reaction, and washing, drying and grinding after the reaction is finished to obtain modified Fe 3 O 4 powder; (5) Mixing the modified sludge-based biochar powder with the modified Fe 3 O 4 powder to obtain a mixture, adding a certain proportion of polyvinyl alcohol and deionized water into the mixture, uniformly stirring, placing into a mould, pressing into blocks, and carbonizing to obtain carbonized products; (6) Uniformly mixing the carbonized product with a conductive agent, an electrode binder and an organic solvent to obtain slurry; (7) And coating the slurry on the surface of foam nickel, and drying to obtain the electrode material.
2. 2. The method for preparing the iron-doped sludge-based biochar supported electrode material according to claim 1, wherein the water content of the sludge is 60-70% in the step (1), the drying temperature is 80-100 ℃ in the step (1), the drying time is 20-36h, the pyrolysis temperature is 400-800 ℃ in the step (1), and the crushed sludge is sieved by a 80-150-mesh sieve.
3. 3. The method for preparing the iron-doped sludge-based biochar supported electrode material according to claim 1, wherein the concentration of the yttrium trichloride solution in the step (2) is 0.002mol/L-0.01mol/L, and the solid-liquid ratio of the sludge-based biochar powder to the yttrium trichloride solution in the step (2) is 1-2:10.
4. 4. The method for preparing an iron-doped sludge-based biochar supported electrode material according to claim 1, wherein the drying temperature in the step (3) is 100-120 ℃.
5. 5. The preparation method of the iron-doped sludge-based biochar supported electrode material, which is characterized in that the mass-volume ratio of Fe 3 O 4 powder to absolute ethyl alcohol in the step (4) is 1-3:100, the addition amount of bis [3- (triethoxysilyl) propyl ] amine in the step (4) is 0.5-1.0% of the mass of absolute ethyl alcohol, the reaction temperature in the step (4) is 60-85 ℃, and the reaction time is 10-20h.
6. 6. The method for preparing the iron-doped sludge-based biochar supported electrode material according to claim 1, wherein the mass ratio of the modified sludge-based biochar powder to the modified Fe 3 O 4 powder in the step (5) is 100:0.1-0.5, the carbonization temperature in the step (5) is 1100-1550 ℃ and the carbonization time is 0.5-1.5h.
7. 7. The method for preparing the iron-doped sludge-based biochar supported electrode material according to claim 1, wherein the mass ratio of the carbonized product, the conductive agent and the electrode binder in the step (6) is 8-10:1-3:2-5.
8. 8. The method for preparing an iron-doped sludge-based biochar supported electrode material according to claim 1, wherein the drying treatment of step (7) comprises drying at 70-80 ℃ for 8-15 hours, followed by heat treatment at 450-600 ℃ for 3-5 hours.
9. 9. The iron-doped sludge-based biochar supported electrode material prepared by the method according to any one of claims 1-8.

Description

Iron-doped sludge-based biochar supported electrode material and preparation method thereof Technical Field The invention relates to the technical field of electrode material preparation, in particular to an iron-doped sludge-based biochar-supported electrode material and a preparation method thereof. Background With the development of urban production in China, the domestic sludge yield is increased sharply, the total sludge yield in China reaches 6500 ten thousand tons at present, and the sludge contains various pathogenic bacteria and various pollutants, and if the sludge is improperly treated, secondary pollution such as air pollution, water pollution, soil pollution and the like is very easy to cause. The sludge can be divided into municipal sludge and industrial sludge according to sources, wherein the municipal sludge is a byproduct generated in the sewage treatment process and mainly comprises organic matters and inorganic components, and is rich in a large amount of heavy metals, carcinogens, P, S, N and other elements. Wherein the organic is mainly from organic components such as protein, fat, carbohydrate and the like in the wastewater, and the inorganic is mainly from chemical synthesis products or from soil. Industrial sludge mainly refers to sludge produced in the process of treating industrial wastewater such as petrochemical industry, electroplating, steel and the like. The industrial sludge contains a large amount of organic matters, heavy metals, trace elements, pathogenic bacteria and the like containing N and P. At present, methods for treating sludge mainly comprise modes of incineration, landfill, ocean dumping and the like, however, the methods have the problems of excessive occupation of soil, serious pollution and the like, so that a method for recycling the sludge is needed to be provided. Based on the method, the invention aims to provide a method for preparing the high-efficiency energy storage composite electrode material by using the sludge, and provides technical references for low-cost electrode materials and resource utilization of the sludge. Disclosure of Invention In view of the above, the invention provides an iron-doped sludge-based biochar-supported electrode material and a preparation method thereof. The invention takes iron element as main electroactive material, realizes iron doping by introducing Fe 3O4, and enhances the pseudocapacitance behavior of the electrode. The yttrium element is used as an auxiliary modifier, so that the conductivity and interface compatibility of the biochar are improved, and the comprehensive electrochemical performance of the electrode material is improved together under the synergistic effect of the yttrium element and the biochar. In order to achieve the above purpose, the present invention adopts the following technical scheme: the invention provides a preparation method of an iron-doped sludge-based biochar supported electrode material, which comprises the following steps: (1) Sequentially dehydrating, drying and pyrolyzing the collected sludge, collecting sludge-based biochar, and crushing and sieving the sludge-based biochar to obtain sludge-based biochar powder; (2) Placing the sludge-based biochar powder into yttrium trichloride solution, and stirring for a certain time to obtain a dispersion liquid containing sludge-based biochar; (3) Adding urea into the dispersion liquid containing the sludge-based biochar to obtain a mixed liquid, wherein the concentration of the urea in the mixed liquid is 0.5 mol/L, transferring the mixed liquid into a high-pressure reaction kettle, carrying out hydrothermal reaction for 6-12 hours at 120-180 ℃, centrifugally separating, collecting solids, and drying the solids to obtain modified sludge-based biochar powder for later use; (4) Placing Fe 3O4 powder in absolute ethyl alcohol, carrying out ultrasonic treatment until the Fe 3O4 powder is uniformly dispersed, then adding bis [3- (triethoxysilyl) propyl ] amine into a system, carrying out heating reaction, and washing, drying and grinding after the reaction is finished to obtain modified Fe 3O4 powder; (5) Mixing the modified sludge-based biochar powder with the modified Fe 3O4 powder to obtain a mixture, adding a certain proportion of polyvinyl alcohol and deionized water into the mixture, uniformly stirring, placing into a mould, pressing into blocks, and carbonizing to obtain carbonized products; (6) Uniformly mixing the carbonized product with a conductive agent, an electrode binder and an organic solvent to obtain slurry; (7) And coating the slurry on the surface of foam nickel, and drying to obtain the electrode material. According to the invention, the Fe 3O4 powder is modified, so that the binding force between the iron element and the modified sludge-based biochar powder is improved, and the active substances are prevented from falling off. According to the invention, the modified sludge-based biochar powder, the modified Fe 3O4, the po