CN114149057A

CN114149057A - Preparation method of EAOPs porous electrode for electrochemical advanced oxidation of wastewater difficult to biochemically use and porous electrode plate

Info

Publication number: CN114149057A
Application number: CN202111535415.5A
Authority: CN
Inventors: 刘超; 丁玉梅; 陈会清
Original assignee: Xiamen Xiuche Environmental Protection Technology Co ltd
Current assignee: Ding Yumei; Xiamen Huache Environmental Protection Technology Co ltd
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2022-03-08
Anticipated expiration: 2041-12-15
Also published as: CN114149057B

Abstract

A preparation method of EAOPs porous electrode difficult to biochemically oxidize waste water electrochemically and a porous electrode plate solve the problem of how to prepare stable electrode with high specific surface area and high surface activity. The porous electrode plate prepared according to the method has a quaternary structure, the porous reticular structure on the electrode plate is a first-level structure, semi-molten particles are attached to the network to form a synapse second-level structure during 3D printing, the electrode plate is vibrated and sieved with a first heterogeneous catalyst to form a third-level structure, and the electrode plate is deposited to form a fourth-level structure.

Description

Preparation method of EAOPs porous electrode for electrochemical advanced oxidation of wastewater difficult to biochemically use and porous electrode plate

Technical Field

The invention belongs to the field of wastewater treatment, and particularly relates to a preparation method of EAOPs porous electrodes for electrochemical advanced oxidation of wastewater difficult to biochemically treat and an electrode plate prepared by the method.

Background

The electro-Fenton reaction is used as an Electrochemical Advanced Oxidation Process (EAOPs), a large amount of hydrogen peroxide is required to be rapidly generated on a cathode plate to generate hydroxyl radicals with strong oxidizing property with iron ions, and then the hydroxyl radicals are contacted with organic matters in a solution, so that the organic matters are oxidized and degraded, and particularly, the electro-Fenton reaction has incomparable advantages compared with other traditional treatment methods for difficultly-biochemical wastewater.

Based on the electro-Fenton reaction mechanism, the contact area between the electrode and the solution is closely related to the process efficiency. At present, the related technical innovation in the field is to increase the specific surface area of catalytic metal and increase the reactive sites as breakthrough points, and a loading method is often adopted.

Patent CN102887567B discloses a modification method of graphite felt material applied to electro-fenton system, which increases specific surface area and reactive sites by loading carbon nanoparticles in situ on the surface of the modified graphite felt material. However, the surface area of the graphite electrode plate is still not increased, and the graphite and the carbon nano tube are dissolved and fall off after the graphite is low in strength and used for a period of time, so that the catalytic effect is lost.

The patent CN108358282B discloses a modified gas diffusion electrode and a preparation method thereof, wherein a catalyst layer formed by carbon black, high-purity conductive graphite powder, nano zero-valent iron, silicotungstic acid, a pore-forming agent, a dispersing agent and polytetrafluoroethylene emulsion is coated on an electronic collection layer, electrochemical catalytic sites are added, a pore structure is improved, a gas-liquid-solid three-phase interface is formed, H is promoted₂O₂The yield of the catalyst is limited, but the strength of the whole catalyst is limited, and the desorption of carbon black and graphite is easy to occur after the catalyst is used for a period of time, so that the disintegration of the whole structure and the loss of the catalytic performance are caused.

Electrodes prepared with the supported technology are prone to structural collapse over time. Dongguan's institute of technology has disclosed patents CN113264574A, CN113149146A, utilizes 3D printing technique to print porous electrode, and compared in the mode of load, 3D printed electrode stability is strong, but 3D prints and influences based on the precision, and the electrode of printing still needs the clout to clear away and polish, and the precision of 3D printing can only obtain millimeter level's pitch-row structure simultaneously, and is limited to the increase of electrode specific surface area.

Therefore, how to obtain the electro-Fenton electrode with high catalytic activity and large reaction area has important significance for treating organic matters in the biochemical-difficult wastewater.

Disclosure of Invention

Based on the defects of the prior art, the invention provides a preparation method of EAOPs porous electrodes difficult to carry out electrochemical advanced oxidation on biochemical wastewater, solves the problem of how to prepare stable electrodes with high specific area and high surface activity, and provides a porous electrode plate with a quaternary structure prepared according to the provided method.

In order to achieve the above object, the invention provides a method for preparing EAOPs porous electrode for electrochemical advanced oxidation of wastewater difficult to be biochemically treated, comprising the following steps:

s1: printing the catalytic active metal into a polar plate with a porous net structure by a 3D printing technology;

s2: cleaning the polar plate, and removing free particles in the polar plate;

s3: taking the polar plate as a screen, introducing a first heterogeneous catalyst into the vibrating screen, and then carrying out compaction treatment on the polar plate;

s4: and (4) carrying out deposition treatment on the polar plate, introducing a second heterogeneous catalyst, and then carrying out high-temperature heat treatment to obtain a final finished product.

As a preferred scheme, the 3D printing technology is selective laser sintering or electron beam melting molding, the catalytic active metal is metal titanium, the aperture of the polar plate is 0.2-5mm, and the thickness of the polar plate is 5-50 mm.

Furthermore, the metallic titanium is titanium spherical particles, and the particle diameter is 40-100 μm.

As a preferred scheme, the cleaning pole plate is cleaned by ultrasonic oscillation and then is swept by high-pressure gas.

Furthermore, the ultrasonic oscillation cleaning frequency is 25-80KHz, the cleaning time is 10-30min, and the pressure of high-pressure gas purging is 0.1-0.6 MPa.

As a preferable mode, the first heterogeneous catalyst is irregular particles, the particle size of the particles is 18 to 1700 μm, and the vibration amplitude of the tap treatment is 0.5 to 3 mm.

Further, after the vibration compaction treatment, calculating the mass ratio of the first heterogeneous catalyst particles loaded on the polar plate to the polar plate, and controlling the mass ratio to be 0.1-5%.

Preferably, the deposition process is physical vapor deposition, chemical vapor deposition or electrochemical deposition.

As a preferable scheme, the treatment temperature of the high-temperature heat treatment is 800-1600 ℃.

In a second aspect, the invention provides an electro-Fenton electrode plate, which is manufactured according to any one of the above methods, the electrode plate has a quaternary structure, the porous reticular structure on the electrode plate is a first-stage structure, semi-molten particles are attached to the network during 3D printing to form a synaptic second-stage structure, the electrode plate is vibrated and sieved by a first heterogeneous catalyst to form a third-stage structure, and the electrode plate is deposited to form the fourth-stage structure.

Compared with the prior art, the method provided by the invention has the beneficial effects that:

1) by preparing the micro-nano composite electro-Fenton catalytic plate with macro-mesoscopic-microscopic four stages, the specific surface area of the material is obviously improved, the contact reaction area of the formed plate and the solution is increased, and the generation of the electro-Fenton catalytic reaction H2O2 is facilitated.

2) By adopting a specific process, the melting degree and the molten pool depth of the 3D printing spherical particles are reduced, more semi-molten particles are obtained to be adhered on the surface of the porous framework, and thus the proportion of the semi-molten particles is increased, and more micron-sized spherical synapse structures are formed.

3) Through the clearance and get rid of the free spherical granule in the polar plate perforating hole, release 3D and print the hollow structure of perforating hole in the polar plate skeleton, prevent that not fused spherical granule from blockking up perforating hole in the skeleton, handle through the sieve that shakes after that, increase the embedding of irregular granule, both guaranteed the whole of macroscopic hole and link up, also improved specific surface area.

4) Two different catalysts are introduced in sequence, so that the electrochemical catalytic activity of the surface of the polar plate is improved.

Drawings

FIG. 1 is a 100-fold scanning electron micrograph of a cut-out portion of a plate in example 1

FIG. 2 is a scanning electron micrograph of the nanostructure of the plate magnified 50000 times of example 1

Detailed Description

Example 1

The method comprises the steps of adopting selective laser melting 3D printing equipment, taking pure titanium spherical particles with the particle size of 40-100 mu m as a raw material, modeling and printing a planar polar plate with the length of 200mm, the width of 200mm and the thickness of 20mm, wherein the aperture is 0.2-1.2 mm. Before forming treatment, uniformly paving pure titanium spherical powder on a workbench of a forming chamber, setting 3D printing parameters, laser power of 100W, scanning speed of 120mm/s and scanning interval of 1.0mm, and processing a polar plate with a macroscopic through porous structure by additive manufacturing;

carrying out ultrasonic oscillation cleaning on the processed polar plate by adopting an ultrasonic cleaner with the frequency of 25KHz for 30min, and then blowing the porous polar plate by using high-pressure gas of 0.6MPa for removing free particles in the through holes of the polar plate;

placing the processed polar plate on a vibrating screen machine, taking the polar plate as a vibrating screen mesh plate, weighing the total weight of the polar plate before and after vibrating screen after the particle size of the vibrating screen particle is 270-800 meshes of irregular nickel powder, vibrating the polar plate for 4 hours, testing the load mass ratio of the polar plate loaded heterogeneous particles, vibrating the polar plate until the load ratio is 4.7%, and stopping vibrating the polar plate;

putting the polar plate into a vacuum magnetron sputtering machine for sputtering deposition. Magnetron sputtering power of 120w, vacuum degree pumping to 3.0 × 10-3Pa for sputtering platinizing treatment, deposition time of 120min, then placing the processed pole plate into a vacuum furnace for high-temperature heat treatment, heating up to 1470 ℃ for heat preservation for 30min, cooling along with the furnace, and then obtaining the final finished product.

Example 2

The method comprises the steps of uniformly paving pure titanium spherical particles with the particle size of 40-100 microns on a bottom plate of a forming chamber by adopting 3D printing equipment of an electron beam melting forming technology as a raw material, modeling and printing a planar pole plate with the length of 150mm, the width of 150mm and the thickness of 30mm, wherein the aperture is 4-5 mm. Setting 3D printing parameters, preheating titanium powder to 600 ℃ by adopting an electron beam with power of 3000W, melting the scanning current of the scanning electron beam to be 13mA, and processing a polar plate with a macroscopic through porous structure by additive manufacturing, wherein the scanning speed of the electron beam is 1000 mm/s;

carrying out ultrasonic oscillation cleaning on the processed polar plate by adopting an ultrasonic cleaner with the frequency of 40KHz for 10min, and then blowing the porous polar plate by using high-pressure gas of 0.1MPa for removing free particles in the through holes of the polar plate;

placing the processed polar plate on a vibrating screen machine, using the polar plate as a vibrating screen plate, wherein the particle size of the vibrating screen particle is irregular palladium particles with 10-16 meshes, the vibration amplitude of the vibrating compaction treatment is 0.5mm, after vibrating screen for 2 hours, vibrating and weighing the total weight of the polar plate before and after vibrating screen, testing the converted load mass ratio of the polar plate load heterogeneous particles, compacting until the load ratio is 0.5%, and stopping the compacting treatment;

putting the polar plate into a mixed solution containing dinitroso diammine platinum and other additives for electrochemical deposition, wherein the deposition current is 2.0A/dm2, the deposition temperature is 60 ℃, the deposition time is 10min, after the polar plate is deposited, cleaning and drying, putting the processed polar plate into a vacuum furnace for high-temperature heat treatment, the temperature rise time is 10 ℃/min, raising the temperature to 1400 ℃, preserving the temperature for 30min, and cooling along with the furnace to obtain a final product.

Claims

1. A preparation method of EAOPs porous electrode for electrochemical advanced oxidation of difficultly biochemical wastewater is characterized by comprising the following steps:

s2: cleaning the polar plate, and removing free particles in the polar plate;

2. The preparation method of the difficult biochemical wastewater electrochemical advanced oxidation EAOPs porous electrode as claimed in claim 1, wherein the step S1 specifically comprises: the 3D printing technology is selective laser melting or electron beam melting molding, the catalytic active metal is metal titanium, the aperture of the polar plate is 0.2-5mm, and the thickness of the polar plate is 5-50 mm.

3. The preparation method of the difficult biochemical waste water electrochemical advanced oxidation EAOPs porous electrode as claimed in claim 2, wherein the metal titanium is titanium spherical particles, and the particle diameter is 40-100 μm.

4. The preparation method of the difficult biochemical wastewater electrochemical advanced oxidation EAOPs porous electrode as claimed in claim 1, wherein the step S2 specifically comprises: cleaning the polar plate by ultrasonic oscillation, and then purging by high-pressure gas.

5. The preparation method of the EAOPs porous electrode for the electrochemical advanced oxidation of the biochemical-refractory wastewater according to claim 4, wherein the ultrasonic oscillation cleaning frequency is 25-80KHz, the cleaning time is 10-30min, and the pressure of the high-pressure gas purging is 0.1-0.6 MPa.

6. The preparation method of the difficult biochemical wastewater electrochemical advanced oxidation EAOPs porous electrode as claimed in claim 1, wherein the step S3 specifically comprises: the first heterogeneous catalyst is irregular particles with the particle size of 18-1700 μm and the vibration amplitude of the tap treatment of 0.5-3 mm.

7. The preparation method of the difficult biochemical waste water electrochemical advanced oxidation EAOPs porous electrode as claimed in claim 6, wherein the step 3 further comprises: and after the compaction treatment, calculating the mass ratio of the first heterogeneous catalyst particles loaded on the polar plate to the polar plate, and controlling the mass ratio to be 0.1-5%.

8. The preparation method of the difficult biochemical wastewater electrochemical advanced oxidation EAOPs porous electrode as claimed in claim 1, wherein the step 4 specifically comprises: the deposition treatment adopts physical vapor deposition, chemical vapor deposition or electrochemical deposition.

9. The preparation method of the difficult biochemical wastewater electrochemical advanced oxidation EAOPs porous electrode as claimed in claim 1, wherein the step 4 specifically comprises: the treatment temperature of the high-temperature heat treatment is 800-1600 ℃.

10. A porous electrode plate made by the method of any one of claims 1-9, wherein the electrode plate has a quaternary structure, the porous network structure on the electrode plate is a first-order structure, semi-molten particles are attached to the network during 3D printing to form a synaptic second-order structure, the electrode plate is vibrated to screen a first heterogeneous catalyst to form a third-order structure, and the electrode plate is deposited to form the quaternary structure.