A filter material made of a porous metal having an open framework

Abstract

The application discloses a kind of filter materials made of porous metal with open skeleton, belong to filter field.The filter material uses porous metal with open skeleton as base material, and sets filter function layer on the surface of porous metal.The porous metal is mainly or entirely composed of open metal skeleton, compared with the porous metal with hollow skeleton structure, it has higher effective specific surface area and higher effective porosity, and shows higher tensile strength, greater elongation rate and the like in mechanical properties, and has higher thermal conductivity, filtration transmittance, high loading capacity and the like.Setting filter function layer on the porous metal with open skeleton can increase the filtration area by more than 30% than ordinary porous metal, and greatly improve the filtration performance.Under similar mechanical strength, the porous metal with open skeleton can save about 15% metal compared with ordinary porous metal, which is an effective means of energy saving and environmental protection, and is an excellent filter material in the field of filtration.

Description

[0001] This application claims priority to Chinese invention application No. 2022114904608, filed on November 25, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of filter material technology and relates to a filter material made of porous metal with an open skeleton. Background Technology

[0003] Porous metals are materials composed of a metal framework and pores. Due to the large number of pores inside the material, compared with solid metal materials, they have characteristics such as low density, large specific surface area, high specific strength, excellent permeability and high temperature resistance. They are often used as substrate materials in the field of filtration.

[0004] A monograph titled *Introduction to Porous Materials* (Liu Peisheng, *Introduction to Porous Materials* [M]. Tsinghua University Press, 2004), on page 193, in section 3.3.4, discloses a method for preparing porous metals by electrodeposition. The process includes substrate pretreatment, conductivity treatment, electroplating, and reduction sintering. Furthermore, on page 196 of the same section, it is pointed out that the porous body obtained after reduction sintering is a three-dimensional network composed of hollow metal prisms.

[0005] However, existing filter materials made of porous metals have a large amount of unusable surface area and voids in their skeletons, and about 25% of the metal material is wasted. Further improvement of the performance of porous metals is urgently needed. Summary of the Invention

[0006] The purpose of this invention is to provide a filter material made of porous metal with an open framework. This invention provides a filter material made of porous metal with an open framework, which, by setting the filter functional layer on the surface of the porous metal with the open framework, opens up most or all of the closed spaces within the hollow framework of the porous metal, increasing the surface area, reducing density, and improving the effective porosity, thereby further improving the performance of the filter material. The effective porosity refers to the proportion of functional pores to all pores. The purpose of this invention is achieved through the following technical solution.

[0007] A filter material is made of porous metal with an open framework, wherein the filter material has a filter layer disposed on the surface of the porous metal with the open framework. The porous metal consists of a metal framework and pores. The metal framework is obtained by depositing metal on the surface of an organic polymer porous material and then removing the organic polymer porous material. The metal framework is entirely open or a mixture of open and hollow frameworks. The open framework includes the space left after the metal deposition layer and the organic polymer porous material are removed, and the remaining space is not completely surrounded by the metal deposition layer but can directly communicate with the external space. The hollow framework includes the space left after the metal deposition layer and the organic polymer porous material are removed, and the remaining space is completely surrounded by the metal deposition layer but cannot directly communicate with the external space.

[0008] For the preparation method of porous metal with an open framework and the morphology of the open framework and the hollow framework involved in this invention, please refer to Chinese Invention Application No. 2023100140947 entitled "Porous Metal with Open Framework and Manufacturing Method Thereof".

[0009] In some specific embodiments, the filter functional layer is a surface layer with mixed wettability. This surface layer is formed on a porous metal surface with a superhydrophilic surface, and then a superhydrophobic film is locally covered on the superhydrophilic surface. The superhydrophilic surface is obtained by chemical oxidation, and the superhydrophilic film is obtained by coating an ethanol solution of a polymer compound with hydrophobic groups onto the superhydrophilic surface.

[0010] In some specific implementations, the filter functional layer is made of a material with hydrophobic and oleophilic properties, including ethylene and propylene materials.

[0011] In some specific embodiments, the filter functional layer is an antibacterial and / or antifungal functional coating formed on the surface of the porous metal; after further increasing the surface area and adhesion of the porous metal through pickling, alkali washing and activation processes, the porous metal is immersed in an antibacterial plating solution and / or an antifungal plating solution to form a functional coating.

[0012] Furthermore, the open frame accounts for 20% to 100% of the total metal frame, preferably 60% to 100%.

[0013] The proportion of open skeletons to all metal skeletons described in this invention can be measured by the following method: Take a piece of porous metal, encapsulate it in resin (e.g., epoxy resin), and then polish the test surface. The test surface can be any one of the four surfaces parallel to the direction of directional metal deposition. After polishing the test surface, select a test area on the test surface with a width equal to the thickness of the porous metal and a length equal to twice the thickness of the porous metal. Calculate the number of open skeletons in the test area and the total number of metal skeletons. If a part of an open skeleton or hollow skeleton is included in the test area, it is considered as one open skeleton or hollow skeleton and accumulated.

[0014] The proportion of open frames to all metal frames = total number of open frames in the test area ÷ total number of all metal frames in the test area × 100%.

[0015] In some specific embodiments, the porous metal is a two-dimensional porous metal, whose metal skeleton is a continuous solid arranged in a polygonal two-dimensional pattern; correspondingly, the pores are columnar and separated between the metal skeleton.

[0016] In some specific embodiments, the porous metal is a three-dimensional porous metal, whose metal skeleton is a continuous solid with a three-dimensional network structure, and the pores between the metal skeletons are interconnected.

[0017] In some specific embodiments, the average pore diameter is 0.05~5mm.

[0018] In some specific embodiments, the thickness of the metal layer of the metal skeleton is 1~1000μm.

[0019] In some specific embodiments, the thickness of the porous metal is 0.005~65mm.

[0020] In some specific embodiments, the metal deposition layer is a dual-mode metal deposition layer composed of two different sizes of grains or a multi-mode metal deposition layer composed of multiple different sizes of grains.

[0021] In some specific embodiments, the metal deposition layer is a single metal material formed from any one of iron, nickel, copper, iron, aluminum, chromium, cadmium, germanium, tin, lead, zinc, gold, silver, titanium, cobalt, vanadium, niobium, hafnium, tantalum, bismuth, molybdenum, tungsten, manganese, platinum, palladium, ruthenium, rhodium, iridium, and osmium, or a multilayer metal material or alloy material formed from two or more of the above metals.

[0022] In some specific implementations, the porous metal is subjected to at least one of the following processes: spraying, coating, electrodeposition, chemical precipitation, and sintering, to form a rough layer on the surface of the porous metal.

[0023] Hollow-framed structures, where the organic polymer porous material is removed, leave a space enclosed by a metal layer, rendering their internal space and the area on the inner wall of the hollow cavity unusable. Open-framed structures, on the other hand, allow the space left after the organic polymer porous material is removed to communicate with the external environment. This space can be used for filling with active materials, and their effective porosity and surface area are greater than those of hollow-framed structures. Porous metals with open-framed structures have a larger specific surface area and superior permeability. Placing the filter layer in a porous metal with an open-framed structure provides over 30% more filtration area than ordinary porous metals, significantly improving filtration performance. Under similar mechanical strength, porous metals with open-framed structures use approximately 15% less metal than ordinary porous metals, making them an effective energy-saving and environmentally friendly method. Furthermore, by roughening the surface of porous metals with open-framed structures, their surface area can be increased by more than three times, making them excellent filter materials in the filtration field.

[0024] The present invention has the following beneficial technical effects:

[0025] (1) The porous metal filter material with an open skeleton provided by the present invention has superior filtration performance and low flow resistance compared with the porous metal filter material made by ordinary template method, and also has a lower bulk density, saving the amount of metal used.

[0026] (2) The porous metal filter material with an open skeleton provided by the present invention is made of metal as a base and has the characteristics of high temperature resistance, high mechanical strength, oxidation resistance, corrosion resistance and long service life. Attached Figure Description

[0027] Figure 1 This is an SEM image of the filter material in Example 2. Implementation

[0028] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention. Example 1

[0029] A filter material of porous metal with an open skeleton is disclosed, wherein a filter functional layer is disposed on the surface of the porous metal with an open skeleton. The filter functional layer is further increased by acid washing, alkali washing and activation processes to increase the surface area and adhesion of the porous metal, and then the functional coating is deposited by immersion in an antibacterial plating solution and an antifungal agent. The porous metal is composed of an open skeleton and a hollow skeleton, with the open skeleton accounting for 80% of the total metal skeleton. The overall thickness of the porous metal is 65 mm, the average pore size is 5 mm, the metal layer thickness of the metal skeleton is 1000 μm, and the metal type is pure nickel.

[0030] Comparative Example 1

[0031] A filter material with porous metal has a filter functional layer disposed on the surface of the porous metal. The filter functional layer is formed by further increasing the surface area and adhesion of the porous metal through acid washing, alkali washing and activation processes, and then by immersion plating with antibacterial plating solution and antifungal agent to form a functional coating. The porous metal is completely composed of a hollow skeleton. The overall thickness of the porous metal is 65 mm, the average pore size is 5 mm, the metal layer thickness of the metal skeleton is 1000 μm, and the metal type is pure nickel.

[0032] The filter material prepared in Example 1 is 27% lighter and has an increased surface area of ​​approximately 35% compared to the filter material prepared in Comparative Example 1. Tests conducted according to the "Emission Standard for Fume from Catering Industry" (GB18483-2001) showed that the fume removal efficiency using the filter material prepared in Example 1 was approximately 7% higher than that using the filter material prepared in Comparative Example 1. Example 2

[0033] A porous metal filter material with an open framework is disclosed. Nickel powder is bonded to the surface of the porous metal through sintering to roughen it. A filter layer, made of polytetrafluoroethylene (PTFE), is disposed on the roughened surface of the porous metal with an open framework. The porous metal is composed of an open framework, which constitutes 100% of the entire metal framework. The overall thickness of the porous metal is 300 mm, with an average pore size of 0.3 mm. The metal layer of the metal framework has a thickness of 500 μm, and the metal is pure nickel. SEM images are shown below. Figure 1 As shown.

[0034] Comparative Example 2

[0035] A porous metal filter material has a filter layer disposed on the surface of the porous metal, the filter layer being polytetrafluoroethylene; the porous metal is entirely composed of a hollow skeleton, the overall thickness of the porous metal is 300 mm, the average pore size is 0.3 mm, the metal layer thickness of the metal skeleton is 500 μm, and the metal type is pure nickel.

[0036] The filter material prepared in Example 2 was 30% heavier and had a surface area increased by approximately 400% compared to the filter material prepared in Comparative Example 2. Tests conducted according to the "Emission Standard for Fume from Catering Industry" (GB18483-2001) showed that the fume removal efficiency of the filter material prepared in Example 2 was approximately 20% higher than that of the filter material prepared in Comparative Example 2.

[0037] Although embodiments of the present invention have been shown and described above, it is understood that these embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and alterations to the above embodiments within the scope of the present invention without departing from its principles and spirit. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A filter material made of porous metal with an open framework, characterized in that, The filter material is a filter layer disposed on the surface of a porous metal with an open framework. The porous metal is composed of a metal framework and pores. The metal framework is obtained by depositing metal on the surface of an organic polymer porous material and then removing the organic polymer porous material. The characteristic feature is that the metal framework is a mixture of an open framework and a hollow framework. The open framework includes the space left after the metal deposition layer and the organic polymer porous material are removed. The space left is not completely surrounded by the metal deposition layer and can be directly connected to the external space. The hollow framework includes the space left after the metal deposition layer and the organic polymer porous material are removed. The space left is completely surrounded by the metal deposition layer and cannot be directly connected to the external space. The filter functional layer is a surface layer with mixed wettability. This surface layer is formed on a porous metal surface with a superhydrophilic surface, and then a superhydrophobic film is locally covered on the superhydrophilic surface. The superhydrophilic surface is obtained by chemical oxidation, and the superhydrophilic film is obtained by coating an ethanol solution of a polymer compound with hydrophobic groups onto the superhydrophilic surface.

2. The filter material according to claim 1, characterized in that, The filter layer is made of a material with hydrophobic and oleophilic properties, such as ethylene or propylene.

3. The filter material according to claim 1, characterized in that, The average pore diameter of the pores is 0.05~5mm.

4. The filter material according to claim 1, characterized in that, The metal deposition layer is either a dual-mode metal deposition layer composed of two different sizes of grains or a multi-mode metal deposition layer composed of multiple different sizes of grains.

5. The filter material according to claim 1, characterized in that, The metal deposition layer is a single metal material formed from any one of iron, nickel, copper, iron, aluminum, chromium, cadmium, germanium, tin, lead, zinc, gold, silver, titanium, cobalt, vanadium, niobium, hafnium, tantalum, bismuth, molybdenum, tungsten, manganese, platinum, palladium, ruthenium, rhodium, iridium, and osmium, or a multilayer metal material or alloy material formed from two or more of the above metals.

6. The filter material according to claim 1, characterized in that, The porous metal is a three-dimensional porous metal.

7. The filter material according to claim 1, characterized in that, The porous metal is a two-dimensional porous metal.

8. The filter material according to claim 1, characterized in that, A rough layer is formed on a porous metal surface by at least one of the following processes: coating, electrodeposition, chemical precipitation, and sintering.

Images