Coating-modified conductive corrosion-resistant ceramic film and preparation method and application thereof

Abstract

The application discloses a coating modified conductive corrosion-resistant ceramic membrane and a preparation method and application thereof, and belongs to the technical field of novel functional materials and water resource recovery. The application solves the current pollution problem of ceramic membranes, the poor corrosion resistance of the membranes, the insufficient tightness of the existing electrodes and the ceramic membranes, and the poor corrosion resistance of the electrodes. The convex surface and the concave surface of the ceramic membrane are respectively coated with gadolinium oxide and isopropyl titanate. The gadolinium oxide can enhance the friction resistance of the membrane, does not affect the conductivity and water permeability, and is also helpful to enhance the corrosion resistance and the anti-pollution ability of the membrane. The isopropyl titanate is changed into titanium dioxide after annealing, and the ceramic membrane is provided with good conductivity, photocatalytic activity and corrosion resistance. The ceramic membrane can be used as an electrode to construct a detachable membrane group device, and is applied by using a modular assembly mode, so that the use efficiency is improved. The coating modified conductive corrosion-resistant ceramic membrane can be widely applied to the fields of electrochemistry, water treatment, environmental protection and material preparation, and has a wide application range.

Description

Technical Field

[0001] This invention belongs to the field of novel functional materials and water resource recycling technology, specifically relating to a coating-modified conductive and corrosion-resistant ceramic membrane, its preparation method, and its application. Background Technology

[0002] Ceramic membranes, as a novel functional material, have shown broad application prospects in electrochemistry, water treatment, environmental protection, and material preparation. However, in many applications, ceramic membranes suffer from fouling problems and insufficient corrosion resistance, significantly reducing their practical applicability. For example, in water treatment, membrane separation technology and electrochemical treatment processes are key means of water purification. However, both methods are facing challenges. Membrane fouling is a prominent issue in electrochemical water purification, with organic matter, inorganic matter, and microorganisms easily adhering to the membrane surface, leading to a decrease in membrane flux. Frequent cleaning and replacement of the membrane increase operating costs and maintenance workload. Furthermore, electrode materials in electrochemical water purification have poor corrosion resistance and are easily corroded by electrolyte solutions, affecting the efficiency and stability of electrochemical reactions and limiting the widespread application of electrochemical treatment technology. Existing electrodes are not tightly bonded to the ceramic membrane, affecting the synergistic effect of the electrochemical reaction and making it difficult to fully leverage the combined advantages of electrochemistry and membrane separation. Summary of the Invention

[0003] To address the problems of membrane fouling, poor corrosion resistance, and insufficient bonding between electrodes and ceramic membranes, as well as poor electrode corrosion resistance in current ceramic membrane applications, this invention provides a coating-modified conductive and corrosion-resistant ceramic membrane, its preparation method, and its application.

[0004] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0005] One objective of this invention is to provide a method for preparing a coating-modified conductive and corrosion-resistant ceramic film. The method involves: fabricating a mold using a mold-making process based on the size and surface shape of the ceramic film; coating a gadolinium oxide precursor on the concave side of the mold; placing the ceramic film in the mold after coating; removing the ceramic film and sintering it; then coating isopropyl titanate on the convex side of the mold; placing the sintered ceramic film in the mold after coating; and finally annealing it to obtain a conductive and corrosion-resistant ceramic film.

[0006] Further specifying the annealing process parameters: a total of 6 annealing cycles, with the first to fifth annealing cycles at a temperature of 300℃ and a time of 5 minutes, and the sixth annealing cycle at a temperature of 500℃ and a time of 2 hours.

[0007] Further specified, the mass ratio of isopropyl titanate to gadolinium oxide is 97:(0.01-0.015).

[0008] The second objective of this invention is to provide a coating-modified conductive and corrosion-resistant ceramic film obtained by the above preparation method.

[0009] The third objective of this invention is to provide an application of the above-mentioned coated conductive and corrosion-resistant ceramic membrane, specifically, the conductive and corrosion-resistant ceramic membrane is used as an electrode in a detachable membrane module.

[0010] Further specifying, the detachable membrane module includes: a slide rail buckle 1, a ceramic membrane electrode 2, a pollution control component 3, and a slide rail buckle 4. The pollution control component 3 is composed of multiple flexible brushes arranged in parallel. The ceramic membrane electrode 2 is disposed opposite to both sides of the pollution control component 3 and is arranged parallel to the pollution control component 3. The slide rail buckle 1 is disposed at the upper and lower ends of the ceramic membrane electrode 2, and the slide rail buckle 4 is disposed at the upper and lower ends of the pollution control component 3.

[0011] Furthermore, the width of slide rail buckle 4 is smaller than the width of slide rail buckle 1.

[0012] Furthermore, the flexible brush material is specified as polytetrafluoroethylene (PTFE).

[0013] The fourth objective of this invention is to provide a pollution control and maintenance device, which includes the aforementioned detachable membrane module 5, aeration pipe 6, outlet pipe 7, water collector 8, and vacuum pump 9, with the water collector 8 located on both sides of the detachable membrane module.

[0014] Further specifying, electrode points are located on the inner side of the water collector, and a sliding groove is located on the outer side.

[0015] Furthermore, the thickness of the water collector is the same as the thickness of the ceramic membrane electrode.

[0016] The beneficial effects of this invention are as follows:

[0017] (1) The conductive and corrosion-resistant ceramic membrane provided by the present invention has been modified by coating on the ceramic membrane, which solves the problems of poor corrosion resistance and easy contamination of existing ceramic membranes. Furthermore, the present invention uses the ceramic membrane directly as the electrode, which avoids the problem of poor bonding between the electrode and the ceramic membrane.

[0018] (2) Traditional ceramic membranes have a striped surface, which results in varying degrees of friction on the uneven surface during use, with higher friction on the convex side. This invention coats the concave side of the ceramic membrane with isopropyl titanate (TTIP) and the convex side with gadolinium oxide (Gd2O3). After annealing, TTIP transforms into TiO2, thus forming a TiO2 coating on the concave side and a Gd2O3 coating on the convex side. Coating the convex side of the ceramic membrane with Gd2O3 enhances its anti-friction properties without affecting its electrical conductivity and water permeability. Furthermore, trace amounts of Gd2O3 help optimize the crystal structure of the composite coating: trace amounts of Gd2O3 can refine the ceramic grain size, reduce grain boundary defects, and significantly reduce the wear rate; in addition, Gd2O3... 3+ TiO2, dissolved in grain boundaries, hinders grain migration, inhibits grain coarsening, and enhances the corrosion resistance of the coating. It also inhibits the adhesion of contaminants, improving the membrane's antifouling ability. TiO2 provides the ceramic membrane with good conductivity, photocatalytic activity, and corrosion resistance. The TiO2 at the concave surface of the ceramic membrane is conductive, allowing current to pass through the membrane. The positive electrode of the ceramic membrane carries a positive charge, repelling positively charged flocs and initiating an electrocoagulation reaction at the positive electrode. The negative electrode carries a negative charge, repelling negatively charged flocs, thus giving the ceramic membrane better antifouling performance. TiO2 and Gd2O3 work synergistically to improve the overall electrochemical performance, corrosion resistance, and antifouling ability of the ceramic membrane. Furthermore, the TiO2 at the concave surface of the ceramic membrane contacts the electrode points on the water collector during the electrochemical water purification process, achieving good conductivity and improving the electrochemical reaction efficiency of the electrochemical water purification system.

[0019] (3) The quality of the raw materials, isopropyl titanate and gadolinium oxide, is strictly controlled during the mixing process of this invention to ensure the uniformity and stability of the coating. The thickness of both the TiO2 coating and the Gd2O3 coating is 25-100 nm, and the resistance is 10-1000 Ω. By adjusting the parameters of the coating equipment, it is ensured that the composite modified coating can be uniformly filled into the depressions on the membrane surface to form a continuous and complete coating layer, so as to give full play to the role of the composite coating. In addition, after annealing, a strong adhesion layer is formed on the surface of the ceramic membrane, and finally a coating modified ceramic membrane is obtained. This membrane has excellent conductivity, corrosion resistance and anti-fouling properties, which can improve the reliability of the electrochemical water purification system and enable it to play a more efficient role in practical applications, meeting the needs of use under complex working conditions.

[0020] (4) The present invention also provides a detachable membrane module with good chemical stability, low friction and good flexibility, which simplifies the maintenance process of electrochemical water purification devices and reduces operation and maintenance costs. The fouling control component in the membrane module is composed of multiple polytetrafluoroethylene fibers arranged in a row. The polytetrafluoroethylene fibers have high chemical stability, low friction coefficient and good flexibility, and can adapt to the electrochemical environment. The fouling control component floats flexibly with the aeration airflow to scrape off pollutants on the surface of the ceramic membrane electrode, while minimizing damage to the ceramic membrane and ensuring membrane flux and stability. The regular and dense arrangement of multiple polytetrafluoroethylene fibers can form a uniform cleaning force distribution.

[0021] (5) This invention uses ceramic membranes as positive and negative electrode carriers respectively, reducing the membrane spacing and allowing for modular assembly. The ceramic membrane electrodes and the fouling control components can be combined and disassembled. Single ceramic membrane electrodes can be used on both sides of the fouling control component, or multiple electrodes can be used. This avoids the drawbacks of complex maintenance and high replacement costs associated with traditional integrated structures, enhancing the flexibility and durability of the equipment and adapting to the continuous optimization needs of fluid filtration efficiency under varying operating conditions. It can adapt to different application scenarios. Through conductivity-enhancing coatings and optimized nanoscale pore structures, the ceramic membrane electrodes achieve simultaneous regulation of membrane fouling control and pollutant degradation, improving the operational stability and reaction rate of the electrochemical water purification system.

[0022] (6) The present invention installs slide clips on both sides of the ceramic membrane electrode and on both sides of the pollution control component. However, the slide clips are different. The slide clips on both sides of the pollution control component do not have water collection function. They are solid slides with a thickness of 5mm.

[0023] In this invention, the water collector used in conjunction with the detachable membrane module adopts a sliding snap-fit ​​on the outside, which makes the connection of the water collector with other components convenient and quick, effectively improving the assembly efficiency and connection reliability of the water purification device, and also facilitating subsequent device disassembly and maintenance.

[0024] (7) This invention employs a gradient annealing method with multiple annealing cycles. During the gradient cooling process of annealing, the crystal phase of TiO2 changes, thereby introducing a continuous structural change at the interface of the coating material due to the crystal phase transformation. Continuous annealing for 6 cycles can effectively reduce stress concentration at the interface, thereby improving the fatigue resistance and thermal stability of the coating. In addition, this invention constructs a gradient composition coating on the concave TiO2 coating and the convex Gd2O3 coating of the ceramic membrane. By controlling the pore size distribution through the composition gradient transition, optimizing the mass transfer path through element diffusion kinetics, and suppressing stress failure through thermal expansion coefficient gradient matching, the above effects are synergistically optimized to keep the flux constant without affecting the pore size of the ceramic membrane, and to improve the rejection rate after energization, thus achieving a balance between high flux and high rejection rate of the ceramic membrane.

[0025] (8) The coating-modified conductive and corrosion-resistant ceramic film of the present invention can be widely used in electrochemistry, water treatment, environmental protection and material preparation, and has a wide range of applications. Attached Figure Description

[0026] Figure 1 These are schematic diagrams of mold preparation and mold design for Example 1;

[0027] Figure 2 This is a schematic diagram of the detachable membrane module in Application Example 1;

[0028] Figure 3 This is a schematic diagram of the structure after the ceramic film electrode and the slide rail snap-fit ​​are installed in Application Example 1;

[0029] Figure 4 This is a schematic diagram of the pollution control and operation and maintenance device in Application Example 1;

[0030] Figure 5 This is a schematic diagram of the electrode point distribution inside the water collector in Application Example 1;

[0031] In the diagram, 1-slide clip, 2-ceramic membrane electrode, 3-pollution control component, 4-slide clip, 5-detachable membrane module, 6-aeration pipe, 7-outlet pipe, 8-water collector, 9-vacuum pump, 10-polytetrafluoroethylene flexible brush. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0035] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0036] Example 1

[0037] Preparation of coating-modified ceramic films:

[0038] (1) Based on the size and surface shape of the alumina ceramic film, a mold is made using a mold-making process. The mold preparation process is as follows: Figure 1 As shown, the mold design fully considers the geometric characteristics of the ceramic film, such as its shape and size, to ensure precise positioning and fixation of the alumina ceramic film during the coating process, preventing displacement or deformation of the ceramic film. Gadolinium oxide precursor is coated onto the concave surface of the mold with a brush. After coating, the alumina ceramic film is placed in the mold, ensuring a tight fit without bubbles or wrinkles. The ceramic film is then removed and sintered at 1250℃ for 2 hours. After sintering, TTIP is coated onto the convex surface of the mold with a brush. The alumina ceramic film is then placed in the mold again, ensuring a tight fit without bubbles or wrinkles. Annealing is then performed to convert TTIP to TiO2, repeated six times. The first to fifth annealing temperatures are 300℃ for 5 minutes, and the sixth annealing temperature is 500℃ for 2 hours. Finally, a coating-modified conductive and corrosion-resistant alumina ceramic film with a coating thickness of 25-100 nm is obtained.

[0039] In this embodiment, during the preparation of the modified ceramic membrane, 4 mL of TTIP and 5 mL of gadolinium oxide precursor were used, with a mass ratio of 97:0.01 between TTIP and gadolinium oxide in the precursor. The gadolinium oxide precursor was prepared as follows: 0.1000 g of pre-calcined gadolinium oxide was weighed and placed in a 100 mL beaker. 10 mL of hydrochloric acid (6 mol / L) was added, and the mixture was heated and stirred at low temperature until completely dissolved (40°C). After cooling, the mixture was transferred to a 100 mL volumetric flask, diluted to the mark with deionized water, and mixed well.

[0040] The resistance of the coating-modified conductive corrosion-resistant alumina ceramic film prepared in this embodiment was tested. The test results showed that the coating resistance was 10-1000Ω. The corrosion resistance of the coating-modified conductive corrosion-resistant ceramic film was tested according to the standard GB / T 37595-2019 (Requirements for the whole life cycle of corrosion control engineering for corrosion-resistant coatings). The results showed that the corrosion depth was reduced by 15-25%.

[0041] Application Example 1

[0042] This application example utilizes the coating-modified conductive and corrosion-resistant alumina ceramic membrane from Example 1 to design and construct a detachable membrane module, such as... Figure 2As shown, the detachable membrane module includes a slide clip 1, a ceramic membrane electrode 2, a fouling control component 3, and a slide clip 4. The fouling control component 3 consists of multiple PTFE flexible brushes (bristles not shown) arranged side by side. First, the coated modified ceramic membrane is cleaned using a combination of professional cleaning agent and ultrasonic cleaning to ensure thorough removal of oil, particulate matter, and other impurities from the membrane surface. Then, it is placed in a dry environment to air dry naturally, ensuring the membrane surface is completely dry and free of any liquid residue. Next, the slide clip 1 is installed at the upper and lower ends of the ceramic membrane electrode 2, and the 5mm slide clip 4 is installed at the upper and lower ends of the fouling control component 3. The fouling control component 3 is then installed inside the ceramic membrane electrode 2 using the slide clips 1 and 4. The ceramic membrane electrodes 2 are arranged parallel to each other on both sides of the fouling control component 3. The ceramic membrane electrode 2 with the slide clip 1 installed is shown below. Figure 3 As shown,

[0043] In this application example, since the ceramic film electrodes used are of the same size, therefore Figure 2 Only one ceramic membrane electrode is drawn on each side of the pollution control component 3.

[0044] The detachable membrane module of the present invention is used in pollution control and maintenance equipment, such as... Figure 4 As shown, the system includes a detachable membrane module 5, an aeration pipe 6, an outlet pipe 7, a water collector 8, and a vacuum pump 9. The water collector 8 is located at both ends of the ceramic membrane electrode 2 in the detachable membrane module 5, and its thickness is the same as the ceramic membrane electrode 2, which is 15mm. A ring of electrode points is arranged inside each water collector, as shown... Figure 5 As shown, these electrode points can come into contact with TiO2 on the ceramic membrane electrode during device operation, thereby playing a conductive role and ensuring uniform current distribution and efficient conduction. The outer side of the water collector adopts a sliding groove design to facilitate the connection of the water collector with other components.

[0045] The aforementioned pollution control and maintenance device is used in the electrochemical water purification process. The water source to be purified is pressurized at a constant speed by the vacuum pump 9 and then continuously enters the constant speed reactor. During the operation of the electrochemical water purification process, the peristaltic pump rotates forward to generate negative pressure inside the ceramic membrane electrode 2, driving the water to filter through the membrane pores. The filtered purified water is collected by the water collector 8 and discharged into the filtered water tank through the outlet pipe 7. The peristaltic pump is connected to the outlet pipe 7 during this electrochemical water purification process. After the water purification process is completed, the vacuum pump 9 stops feeding water, and the peristaltic pump starts to reverse for backwashing. The aeration system starts aeration through the aeration pipe 6. The pollution control component 3 begins to float under the disturbance of the backwash water flow and aeration. Its surface flexible brush scrapes the filter cake layer formed on the surface of the ceramic membrane electrode 2, reducing membrane fouling.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a coating-modified conductive and corrosion-resistant ceramic film, characterized in that, The preparation method is as follows: according to the size and surface shape of the ceramic film, a mold is made by a mold-making process. Gadolinium oxide precursor is coated on the concave surface of the mold. After coating, the ceramic film is placed in the mold. Then, the ceramic film is taken out and sintered. Subsequently, isopropyl titanate is coated on the convex surface of the mold. After coating, the sintered ceramic film is placed in the mold and then annealed to obtain a conductive and corrosion-resistant ceramic film.

2. The preparation method according to claim 1, characterized in that, The annealing process parameters are as follows: annealing is performed 6 times in total. The first to fifth annealing temperatures are 300℃ and the time is 5 minutes. The sixth annealing temperature is 500℃ and the time is 2 hours.

3. The preparation method according to claim 1, characterized in that, The mass ratio of isopropyl titanate to gadolinium oxide is 97:(0.01-0.015).

4. A coating-modified conductive and corrosion-resistant ceramic film, characterized in that, Prepared by the method described in any one of claims 1-3.

5. The application of the coating-modified conductive and corrosion-resistant ceramic film according to claim 4, characterized in that, The conductive and corrosion-resistant ceramic membrane is used as an electrode in a detachable membrane module.

6. The application according to claim 5, characterized in that, The detachable membrane module includes a slide clip (1), a ceramic membrane electrode (2), a pollution control component (3), and a slide clip (4). The pollution control component (3) is composed of multiple flexible brushes arranged in parallel; The ceramic membrane electrode (2) is arranged opposite to each other on both sides of the pollution control component (3), and the ceramic membrane electrode (2) is arranged parallel to the pollution control component (3); The slide rail buckle (1) is set at the upper and lower ends of the ceramic membrane electrode (2), and the slide rail buckle (4) is set at the upper and lower ends of the pollution control component (3).

7. The application according to claim 6, characterized in that, The width of the slide rail buckle (4) is smaller than the width of the slide rail buckle (1).

8. The application according to claim 6, characterized in that, The flexible brush material is polytetrafluoroethylene.

9. A pollution control and maintenance device, characterized in that, The device includes: a detachable membrane module (5) comprising the conductive and corrosion-resistant ceramic membrane as described in claim 4, an aeration pipe (6), an outlet pipe (7), a water collector (8), and a vacuum pump (9).

10. The apparatus according to claim 9, characterized in that, Electrode points are provided on the inner side of the water collector (8), and a sliding groove is provided on the outer side.

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