A high-temperature resistant filter material, its preparation method and application

Abstract

The present invention belongs to the technical field of filter materials, and provides a high-temperature resistant filter material, a preparation method thereof and an application. The method of the present invention includes: adding TiO2 / activated carbon powder into ammonium metavanadate, cerium nitrate hexahydrate and water, performing calcination and then acidification treatment to obtain an acidified composite catalyst; spinning an organic matter and the acidified composite catalyst, followed by pre-needling and main needling; impregnating the needle-punched felt in a catalyst suspension and then drying it, scraping a polytetrafluoroethylene foam coating on the upper and lower surfaces of the dried needle-punched felt, and then hot-pressing a polytetrafluoroethylene microporous membrane on the upper surface. By adding activated carbon subjected to high-temperature heat treatment, the present invention increases the adsorption capacity of activated carbon for dioxins, and at the same time, in cooperation with the composite catalyst, while ensuring the dust removal and filtration efficiency, improves the removal rate of dioxins. The acidification treatment of the composite catalyst protects the active components in the filter material and improves its catalytic activity and the ability to resist alkali metal poisoning.

Description

Technical Field

[0001] The present invention relates to the technical field of filter materials, and in particular to a high-temperature resistant filter material, a preparation method thereof, and an application thereof. Background Art

[0002] Dioxin is a general term for chlorinated polynuclear aromatic compounds, including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Dioxin is a pollutant that can cause serious harm to organisms. It can exist in the environment for a long time. Once it enters an organism, it will accumulate in the organism and is difficult to be excreted from the body. With the continuous acceleration of the industrialization process, environmental pollution problems caused by high-temperature waste gas emissions and waste combustion are becoming more and more serious. Dioxin is mainly generated during the process of waste incineration and can enter the surrounding environment through flue gas, fly ash, etc., thus causing serious air pollution and threatening national health.

[0003] In the initial stage, dioxin was mainly removed by adsorbing it on the surface and pores of activated carbon. For example, Chinese Patent CN118320794A discloses that dioxin can be adsorbed by activated carbon, but this method cannot degrade dioxin, and the regeneration efficiency is low, and secondary pollution is easily caused during the regeneration process. Currently, dioxin is mainly eliminated by catalytic degradation using noble metal and transition metal catalysts. The dioxin catalytic technology can degrade dioxin through redox reactions to generate carbon dioxide, hydrogen chloride, water, etc. It has the characteristics of low energy consumption, high efficiency, and few secondary pollutants, and can directly decompose harmful substances into harmless substances. For example, Chinese Patent CN115845873A provides a catalyst composed of noble metal Pt and transition metal Ni that can degrade dioxin at low temperatures, but the cost is high and the degradation efficiency is low.

[0004] Therefore, it is of great significance to propose a high-temperature resistant filter material for efficiently eliminating harmful gases based on catalytic degradation technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-temperature resistant filter material, a preparation method thereof, and an application thereof in order to overcome the deficiencies of the prior art.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of a high-temperature resistant filter material, comprising the following steps:

[0008] 1) Mix tetrabutyl titanate, acetic acid, absolute ethanol, and activated carbon to obtain a mud material; calcine the mud material to obtain TiO2 / activated carbon powder;

[0009] 2) Mix ammonium metavanadate, cerium nitrate hexahydrate and water to obtain a mixed solution; add the TiO2 / activated carbon powder into the mixed solution to obtain a mud; calcine the mud to obtain a V2O5-CeO2-TiO2 / activated carbon multi-component composite catalyst;

[0010] 3) Acidify, wash and dry the multi-component composite catalyst in sequence to obtain an acidified composite catalyst;

[0011] 4) Spin the organic matter and the acidified composite catalyst, and then perform pre-needling and main needling in sequence to obtain a needled felt;

[0012] 5) Ultrasonically oscillate the acidified composite catalyst and water to obtain a catalyst suspension; impregnate the needled felt in the catalyst suspension and then dry it to obtain a needled felt loaded with the catalyst;

[0013] 6) Mix polytetrafluoroethylene dispersion, stabilizer, foaming agent and water and then foam them to obtain a foam coating;

[0014] 7) Knife-coat the foam coating on the upper and lower surfaces of the needled felt loaded with the catalyst, and then hot-press a polytetrafluoroethylene microporous membrane on the upper surface of the needled felt to obtain a high-temperature resistant filter material.

[0015] Preferably, the volume ratio of tetrabutyl titanate, acetic acid and absolute ethanol in step 1) is 1:1.2 - 2:4.4 - 5.5, and the total volume ratio of tetrabutyl titanate, acetic acid and absolute ethanol to the volume of activated carbon is 1:0.8 - 1.2;

[0016] The calcination temperature is 900 - 950 °C, the calcination time is 2 - 4 h, and the calcination atmosphere is a nitrogen atmosphere.

[0017] Preferably, the mass ratio of ammonium metavanadate to cerium nitrate hexahydrate in step 2) is 1:0.6 - 0.8, and the mass concentration of the mixed solution is 2 - 10%;

[0018] The mixing temperature is 60 - 80 °C, the mixing time is 3 - 4 h, the calcination temperature is 400 - 500 °C, the calcination time is 2 - 4 h, and the calcination atmosphere is a nitrogen atmosphere.

[0019] Preferably, the reagent for acidification treatment in step 3) is sulfuric acid, the concentration of sulfuric acid is 0.08 - 0.12 mol / L, the acidification treatment time is 4 - 6 h, the reagent for washing is water, and wash until the pH value of the multi-component composite catalyst no longer changes; the drying temperature is 90 - 105 °C, and the drying time is 12 - 18 h.

[0020] Preferably, the mass ratio of the organic matter to the acidified composite catalyst in step 4) is 10-30:70-90, and the organic matter includes one or more of polyether ether ketone, polytetrafluoroethylene, and polyphenylene sulfide;

[0021] The depth of the pre-needling is 10-14 mm, and the density is 70-140 needles / cm 2 , the depth of the main needling is 6-12 mm, and the density is 1000-1500 needles / cm 2 .

[0022] Preferably, the mass concentration of the catalyst suspension in step 5) is 1-8%, the impregnation time is 6-8 h, and the drying temperature is 80-100 °C.

[0023] The catalyst loading of the needle-punched felt is 80-120 g / m 2 ; the total gram weight of the needle-punched felt is 200-600 g / m 2 .

[0024] Preferably, the solid content of the polytetrafluoroethylene dispersion in step 6) is 57-63%; the mass ratio of the polytetrafluoroethylene dispersion, the stabilizer, the foaming agent, and water is 1.5-2:0.05-0.1:0.6-1:97-98;

[0025] The foaming time is 10-15 min, stirring is carried out during the foaming process, and the stirring rate is 3000-5000 r / min; the foaming ratio of the foam coating is 4-6:1;

[0026] The foaming agent is sodium cocoyl amphoacetate or alkyl glycoside, and the stabilizer is Tween 80 or sodium dodecyl sulfate.

[0027] Preferably, the thickness of the scraping in step 7) is 0.4-0.6 cm; the temperature of the hot pressing is 200-300 °C, the hot pressing time is 8-10 s, and the hot pressing pressure is 1-3 MPa;

[0028] The gram weight of the polytetrafluoroethylene microporous membrane is 3-4 g / m 2 , the thickness is 10-15 μm, the pore diameter is 0.6-0.8 μm, and the air permeability is 70-100 L / m 2 ·s.

[0029] The present invention also provides a high-temperature resistant filter material prepared by the preparation method described above.

[0030] The present invention also provides the application of the high-temperature resistant filter material in removing dioxins.

[0031] The beneficial effects of the present invention include the following points:

[0032] 1) The high-temperature resistant filter material of the present invention reduces the content of oxygen-containing functional groups on the surface of activated carbon by adding heat-treated activated carbon at high temperature, increases the adsorption capacity of activated carbon for dioxins, and simultaneously synergistically acts with the composite catalyst to improve the removal rate of dioxins by the material while ensuring the dust removal and filtration efficiency.

[0033] 2) The present invention protects the active components in the filter material and improves its catalytic activity and the ability to resist alkali metal poisoning by acid-treating the composite catalyst.

[0034] 3) The filter material of the present invention can be used for a long time at a temperature of 230 - 260 °C, and the instantaneous maximum use temperature even reaches 280 °C. The high-temperature resistant filter material of the present invention can be prepared into filter bags or filter cartridges and used as a dust removal device in multiple fields such as coal combustion, thermal power generation, asphalt, steel, and waste incineration. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a process flow chart for the preparation of the high-temperature resistant filter material of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present invention provides a method for preparing a high-temperature resistant filter material, which comprises the following steps:

[0037] 1) Mix tetrabutyl titanate, acetic acid, absolute ethanol, and activated carbon to obtain a mud-like material; calcine the mud-like material to obtain TiO₂ / activated carbon powder;

[0038] 2) Mix ammonium metavanadate, cerium nitrate hexahydrate, and water to obtain a mixed solution; add the TiO₂ / activated carbon powder to the mixed solution to obtain a mud-like material; calcine the mud-like material to obtain a V₂O₅-CeO₂-TiO₂ / activated carbon multi-component composite catalyst;

[0039] 3) Sequentially perform acidification treatment, washing, and drying on the multi-component composite catalyst to obtain an acidified composite catalyst;

[0040] 4) Spin the organic matter and the acidified composite catalyst and then sequentially perform pre-needling and main needling to obtain a needle-punched felt;

[0041] 5) Ultrasonically oscillate the acidified composite catalyst and water to obtain a catalyst suspension; impregnate the needle-punched felt in the catalyst suspension and then dry it to obtain a needle-punched felt loaded with the catalyst;

[0042] 6) Mix polytetrafluoroethylene dispersion, stabilizer, foaming agent, and water and then foam them to obtain a foam coating;

[0043] 7) Scrape the foam coating on the upper and lower surfaces of the needle-punched felt loaded with the catalyst, and then hot-press a polytetrafluoroethylene microporous membrane on the upper surface of the needle-punched felt to obtain the high-temperature resistant filter material.

[0044] In the present invention, the volume ratio of tetrabutyl titanate, acetic acid and absolute ethanol in step 1) is preferably 1:1.2 - 2:4.4 - 5.5, more preferably 1:1.4 - 1.8:4.6 - 5.2, and still more preferably 1:1.6:4.8 - 5.0; the volume ratio of the total volume of tetrabutyl titanate, acetic acid and absolute ethanol to the volume of activated carbon is preferably 1:0.8 - 1.2, more preferably 1:0.9 - 1.1, and still more preferably 1:1;

[0045] The calcination temperature is preferably 900 - 950 °C, more preferably 910 - 940 °C, and still more preferably 920 - 930 °C. The calcination time is preferably 2 - 4 h, more preferably 2.5 - 3.5 h, and still more preferably 3 h. The calcination atmosphere is preferably a nitrogen atmosphere.

[0046] In the present invention, the concentration of acetic acid is preferably 0.8 - 1 mol / L, more preferably 0.9 mol / L.

[0047] In the present invention, the mixing in step 1) is preferably the first mixing of tetrabutyl titanate, acetic acid and absolute ethanol, and the second mixing of the first mixed solution and activated carbon; the first mixing time is preferably 15 - 25 min, more preferably 18 - 22 min, and still more preferably 20 min. Magnetic stirring is carried out during the first mixing process.

[0048] In the present invention, after the calcination in step 1) is completed, the calcination product is preferably pulverized and sieved to obtain TiO2 / activated carbon powder; the mesh number of sieving is preferably 60 mesh.

[0049] In the present invention, the mass ratio of ammonium metavanadate and cerium nitrate hexahydrate in step 2) is preferably 1:0.6 - 0.8, more preferably 1:0.65 - 0.75, and still more preferably 1:0.7. The mass concentration of the mixed solution is preferably 2 - 10%, more preferably 3 - 8%, and still more preferably 5 - 6%.

[0050] In the present invention, the mass ratio of TiO2 / activated carbon powder to the mixed solution is preferably 0.6 - 0.8:1, more preferably 0.65 - 0.75:1, and still more preferably 0.7:1.

[0051] In the present invention, the mixing temperature in step 2) is preferably 60 - 80 °C, more preferably 65 - 75 °C, and still more preferably 70 °C. The mixing time is preferably 3 - 4 h, more preferably 3.5 h. The calcination temperature is preferably 400 - 500 °C, more preferably 420 - 480 °C, and still more preferably 440 - 450 °C. The calcination time is preferably 2 - 4 h, more preferably 2.5 - 3.5 h, and still more preferably 3 h. The calcination atmosphere is preferably a nitrogen atmosphere.

[0052] In the present invention, after the calcination in step 2) is completed, the calcination product is preferably pulverized and sieved to obtain a V2O5-CeO2-TiO2 / activated carbon composite catalyst; the mesh number of sieving is preferably 60 mesh.

[0053] In the present invention, the reagent for the acidification treatment in step 3) is preferably sulfuric acid, the concentration of sulfuric acid is preferably 0.08 - 0.12 mol / L, more preferably 0.09 - 0.11 mol / L, and even more preferably 0.1 mol / L; the time for the acidification treatment is preferably 4 - 6 h, more preferably 4.5 - 5.5 h, and even more preferably 5 h; the reagent for washing is preferably water, and the washing is carried out until the pH value of the composite catalyst no longer changes; the drying temperature is preferably 90 - 105 °C, more preferably 95 - 100 °C, and the drying time is preferably 12 - 18 h, more preferably 13 - 17 h, and even more preferably 15 - 16 h.

[0054] In the present invention, the mass ratio of the organic matter to the acidified composite catalyst in step 4) is preferably 10 - 30:70 - 90, more preferably 15 - 25:75 - 85, and even more preferably 20:80; the organic matter preferably comprises one or more of polyether ether ketone, polytetrafluoroethylene, and polyphenylene sulfide.

[0055] In the present invention, the specific process of spinning is preferably as follows: the acidified composite catalyst is placed in absolute ethanol and ultrasonically oscillated at 100 Hz for 2 h to prepare a dispersion with a mass concentration of 10 - 20%. The organic matter pellets are ground into powder form, and the organic matter powder is added to the dispersion (the mass ratio of the organic matter powder to the acidified composite catalyst is 10 - 30:70 - 90), and stirred in a mechanical mixer rotating at 200 r / min for 24 h until the mixture is semi-dry. The mixture is dried in an oven at 60 °C for 48 h, and after removing the solvent, it is melt-spun. The spinning temperature is 415 °C, the temperature of the hot runner is 300 °C, the draw ratio is 3 times, the draw temperature is 200 °C, the draw rate is 200 cm / min, and the linear density of the fiber filaments obtained by spinning is 21.13 dtex, the breaking strength can reach 3.94 cN / dtex, and the breaking elongation is 14.73%.

[0056] In the present invention, the depth of the pre-needling in step 4) is preferably 10 - 14 mm, more preferably 11 - 13 mm, and even more preferably 12 mm, and the density is preferably 70 - 140 needles / cm 2 , more preferably 80 - 120 needles / cm 2 , even more preferably 100 - 110 needles / cm 2 ; the depth of the main needling is preferably 6 - 12 mm, more preferably 8 - 10 mm, and even more preferably 9 mm, and the density is preferably 1000 - 1500 needles / cm 2, further preferably 1100 - 1400 needles / cm 2 , more preferably 1200 - 1300 needles / cm 2 .

[0057] In the present invention, the mass concentration of the catalyst suspension described in step 5) is preferably 1 - 8%, further preferably 3 - 6%, and more preferably 4 - 5%; the impregnation time is preferably 6 - 8 h, further preferably 6.5 - 7.5 h, and more preferably 7 h; the drying temperature is preferably 80 - 100 °C, further preferably 85 - 95 °C, and more preferably 90 °C;

[0058] The catalyst loading of the needle-punched felt is preferably 80 - 120 g / m 2 , further preferably 90 - 110 g / m 2 ; the total gram weight of the needle-punched felt is preferably 200 - 600 g / m 2 , further preferably 300 - 500 g / m 2 .

[0059] In the present invention, the solid content of the polytetrafluoroethylene dispersion liquid described in step 6) is preferably 57 - 63%, further preferably 58 - 62%, and more preferably 60 - 61%; the mass ratio of the polytetrafluoroethylene dispersion liquid, stabilizer, foaming agent, and water is preferably 1.5 - 2:0.05 - 0.1:0.6 - 1:97 - 98, further preferably 1.6 - 1.9:0.06 - 0.09:0.7 - 0.9:97.2 - 97.8, and more preferably 1.7 - 1.8:0.07 - 0.08:0.8:97.5 - 97.6.

[0060] In the present invention, the foaming time described in step 6) is preferably 10 - 15 min, further preferably 11 - 14 min, and more preferably 12 - 13 min; stirring is carried out during the foaming process, and the stirring rate is preferably 3000 - 5000 r / min, further preferably 3500 - 4500 r / min, and more preferably 4000 r / min; the foaming ratio of the foam coating is preferably 4 - 6:1, further preferably 4.5 - 5.5:1, and more preferably 5:1;

[0061] The foaming agent is preferably sodium cocoyl amphoacetate or alkyl glycoside, and the stabilizer is preferably Tween 80 or sodium dodecyl sulfate.

[0062] In the present invention, the polytetrafluoroethylene foam coating not only fixes the catalyst particles on the needle-punched felt but also increases the bonding strength between the needle-punched felt and the PTFE microporous membrane.

[0063] In the present invention, the thickness of the scraping coating in step 7) is preferably 0.4 - 0.6 cm, more preferably 0.45 - 0.55 cm, and most preferably 0.5 cm; the temperature of the hot pressing is preferably 200 - 300 °C, more preferably 220 - 280 °C, and most preferably 240 - 250 °C; the time of the hot pressing is preferably 8 - 10 s, more preferably 9 s; the pressure of the hot pressing is preferably 1 - 3 MPa, more preferably 1.5 - 2.5 MPa, and most preferably 2 MPa.

[0064] In the present invention, the grammage of the polytetrafluoroethylene microporous membrane in step 7) is preferably 3 - 4 g / m 2 , more preferably 3.5 g / m 2 , the thickness is preferably 10 - 15 μm, more preferably 11 - 14 μm, and most preferably 12 - 13 μm, the pore diameter is preferably 0.6 - 0.8 μm, more preferably 0.7 μm, and the air permeability is preferably 70 - 100 L / m 2 ·s, more preferably 80 - 90 L / m 2 ·s.

[0065] In the present invention, the polytetrafluoroethylene (PTFE) microporous membrane mainly functions as dust removal in the filter material, so that the filtration efficiency of the filter material is not less than 99.75%; in the present invention, one or more of polyether ether ketone, polytetrafluoroethylene and polyphenylene sulfide fibers are mixed with a catalyst for spinning, and the needled felt is obtained through mixing, opening, carding, web forming, needling and edge cutting and winding, and the needled felt is used as the matrix of the composite catalytic filter bag.

[0066] The present invention also provides a high-temperature resistant filter material prepared by the preparation method described above.

[0067] The present invention also provides the application of the high-temperature resistant filter material in removing dioxins.

[0068] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0069] In the embodiment, the specific process of mixing and spinning polyetheretherketone with the acidified composite catalyst is as follows: The acidified composite catalyst is placed in absolute ethanol and ultrasonically oscillated at 100 Hz for 2 h to obtain a dispersion with a mass concentration of 15%. The polyetheretherketone pellets are ground into powder form. The polyetheretherketone powder is added to the dispersion (the mass ratio of the polyetheretherketone powder to the acidified composite catalyst is 20:80), and stirred in a mechanical mixer rotating at 200 r / min for 24 h until the mixture is semi-dry. The mixture is dried in an oven at 60 °C for 48 h, and after removing the solvent, it is melt-spun. The spinning temperature is 415 °C, the temperature of the hot runner is 300 °C, the draw ratio is 3 times, the draw temperature is 200 °C, the draw rate is 200 cm / min, and the linear density of the fiber filaments obtained by spinning is 21.13 dtex, the breaking strength can reach 3.94 cN / dtex, and the elongation at break is 14.73%.

[0070] Example 1

[0071] Tetrabutyl titanate, acetic acid (concentration 0.8 mol / L) and absolute ethanol with a volume ratio of 1:1.2:4.4 are mixed and magnetically stirred (rotation speed 500 r / min) for 20 min to obtain a mixed solution; the mixed solution and activated carbon are mixed evenly according to a volume ratio of 1:0.8 to obtain a mud-like material, and the mud-like material is calcined in a nitrogen atmosphere at 950 °C for 4 h. The calcined product is pulverized and passed through a 60-mesh sieve to obtain TiO2 / activated carbon powder.

[0072] Ammonium metavanadate and cerium nitrate hexahydrate with a mass ratio of 1:0.6 are added to deionized water at 60 °C and stirred for 4 h to obtain a mixed solution with a mass concentration of 6%; the TiO2 / activated carbon powder is added to the mixed solution (the mass ratio of the TiO2 / activated carbon powder to the mixed solution is 0.6:1) and mixed evenly to obtain a mud-like material. The mud-like material is calcined in a nitrogen atmosphere at 400 °C for 2 h. The calcined product is pulverized and passed through a 60-mesh sieve to obtain a V2O5-CeO2-TiO2 / activated carbon multi-component composite catalyst.

[0073] The multi-component composite catalyst is acidified by soaking in 0.1 mol / L sulfuric acid for 4 h, then washed with deionized water until the pH value no longer changes, and then the composite catalyst is dried in an oven at 90 °C for 12 h to obtain the acidified composite catalyst.

[0074] The polyetheretherketone and the acidified composite catalyst are mixed and spun. The fiber filaments are subjected to mixed opening, carding, web laying, needling, and edge trimming and winding to obtain a needle-punched felt. After the fiber filaments are web-laid, pre-needling is carried out to form a preliminary embryo felt. The pre-needling depth is 10 mm, and the pre-needling density is 80 needles / cm 2 , and after pre-needling, it is further subjected to main needling by an upper and lower needle punching main needling machine to reinforce and form a needle-punched felt. The main needling depth is 6 mm, and the main needling density is 1100 needles / cm2 ; The needled felt serves as the substrate of the composite catalytic filter bag, with a total gram weight of 350 g / m 2 .

[0075] The prepared acidified composite catalyst is placed in deionized water and ultrasonicated (frequency of 100 Hz) for 2 h to obtain a catalyst suspension with a mass concentration of 2%. The needled felt is immersed in the catalyst suspension for 6 h and then dried at 80 °C to obtain a needled felt loaded with the catalyst. The catalyst loading of the needled felt is 85 g / m 2 .

[0076] The PTFE concentrated dispersion (the solid content of the PTFE concentrated dispersion is 60%), the stabilizer sodium dodecyl sulfate, the foaming agent alkyl polyglycoside (APG), and deionized water are mixed (the mass ratio of the PTFE concentrated dispersion, the stabilizer, the foaming agent, and deionized water is 1.5:0.05:0.6:97). The mixed solution is foamed in a stirrer, and the stirrer stirs at a high speed of 3500 r / min for 10 min to obtain a stable foam coating with a foaming ratio of 4:1. The foam coating is respectively scraped onto the upper and lower surfaces of the needled felt loaded with the catalyst (the scraping thickness of the upper and lower surfaces is 0.5 cm). Then, a PTFE microporous membrane is hot-pressed on the upper surface. The gram weight of the PTFE microporous membrane is 3 g / m 2 , with a thickness of 12 μm, a pore diameter of 0.6 μm, and an air permeability of 80 L / m 2 ·s; The hot-pressing temperature is 250 °C, the time is 9 s, and the pressure is 2 MPa to obtain a high-temperature resistant filter material.

[0077] Example 2

[0078] Tetrabutyl titanate, acetic acid (concentration of 0.9 mol / L), and absolute ethanol with a volume ratio of 1:1.6:4.8 are mixed and magnetically stirred (rotation speed of 500 r / min) for 20 min to obtain a mixed solution; The mixed solution is mixed evenly with activated carbon according to a volume ratio of 1:0.8 to obtain a mud material. The mud material is calcined at 950 °C for 4 h in a nitrogen atmosphere. The calcined product is pulverized and passed through a 60-mesh sieve to obtain TiO2 / activated carbon powder.

[0079] Ammonium metavanadate and cerium nitrate hexahydrate with a mass ratio of 1:0.6 are added to deionized water at 60 °C and stirred for 4 h to obtain a mixed solution with a mass concentration of 6%; The TiO2 / activated carbon powder is added to the mixed solution (the mass ratio of the TiO2 / activated carbon powder to the mixed solution is 0.6:1) and mixed evenly to obtain a mud material. The mud material is calcined at 400 °C for 2 h in a nitrogen atmosphere. The calcined product is pulverized and passed through a 60-mesh sieve to obtain a V2O5-CeO2-TiO2 / activated carbon multi-component composite catalyst.

[0080] The multi-component composite catalyst was acidified by soaking it in 0.1 mol / L sulfuric acid for 4 h, and then the composite catalyst was washed with deionized water until the pH value no longer changed. Then the composite catalyst was dried in an oven at 100 °C for 12 h to obtain the acidified composite catalyst.

[0081] Polyetheretherketone and the acidified composite catalyst were mixed and spun. The fiber filaments were subjected to mixed opening, carding, web laying, needling, and edge trimming and winding to obtain a needle-punched felt. After the fiber filaments were web-laid, pre-needling was carried out to form a preliminary embryo felt. The pre-needling depth was 10 mm, and the pre-needling density was 80 needles / cm 2 , and after pre-needling, main needling was carried out through upper and lower main needling machines to reinforce and form a needle-punched felt. The main needling depth was 6 mm, and the main needling density was 1100 needles / cm 2 ; The needle-punched felt was used as the substrate of the composite catalytic filter bag, and the total gram weight was 350 g / m 2 .

[0082] The prepared acidified composite catalyst was placed in deionized water and ultrasonically oscillated (frequency 100 Hz) for 2 h to prepare a catalyst suspension with a mass concentration of 2%. The needle-punched felt was soaked in the catalyst suspension for 6 h and then dried at 80 °C to obtain a needle-punched felt loaded with the catalyst. The catalyst loading amount of the needle-punched felt was 85 g / m 2 .

[0083] A PTFE concentrated dispersion liquid (the solid content of the PTFE concentrated dispersion liquid was 60%), a stabilizer sodium dodecyl sulfate, a foaming agent alkyl polyglycoside (APG), and deionized water were mixed (the mass ratio of the PTFE concentrated dispersion liquid, the stabilizer, the foaming agent, and deionized water was 1.5:0.05:0.6:97). The mixed liquid was foamed in a stirrer, and the stirrer was stirred at a high speed of 3500 r / min for 10 min to obtain a stable foam coating with a foaming ratio of 4:1. The foam coating was respectively scraped on the upper and lower surfaces of the needle-punched felt loaded with the catalyst (the scraping thickness of the upper and lower surfaces was 0.5 cm). Then a PTFE microporous membrane was hot-pressed on the upper surface. The gram weight of the PTFE microporous membrane was 3 g / m 2 , the thickness was 12 μm, the pore diameter was 0.6 μm, and the air permeability was 80 L / m 2 ·s; The hot-pressing temperature was 250 °C, the time was 9 s, and the pressure was 2 MPa to obtain a high-temperature resistant filtering material.

[0084] Example 3

[0085] Mix tetrabutyl titanate, acetic acid (concentration: 1 mol / L), and absolute ethanol in a volume ratio of 1:1.2:4.4, and stir magnetically (rotation speed: 500 r / min) for 20 min to obtain a mixed solution; mix the mixed solution with activated carbon in a volume ratio of 1:0.8 evenly to obtain a mud material. The mud material is calcined at 950 °C for 4 h in a nitrogen atmosphere. The calcined product is crushed and passed through a 60-mesh sieve to obtain TiO₂ / activated carbon powder.

[0086] Add ammonium metavanadate and cerium nitrate hexahydrate in a mass ratio of 1:0.7 to deionized water at 70 °C, and stir for 4 h to obtain a mixed solution with a mass concentration of 8%; add TiO₂ / activated carbon powder to the mixed solution (the mass ratio of TiO₂ / activated carbon powder to the mixed solution is 0.6:1) and mix evenly to obtain a mud material. The mud material is calcined at 450 °C for 2 h in a nitrogen atmosphere. The calcined product is crushed and passed through a 60-mesh sieve to obtain a V₂O₅-CeO₂-TiO₂ / activated carbon multi-component composite catalyst.

[0087] Soak the multi-component composite catalyst in 0.1 mol / L sulfuric acid for 4 h for acidification treatment, then wash the composite catalyst with deionized water until the pH value no longer changes, and then dry the composite catalyst in an oven at 90 °C for 12 h to obtain an acidified composite catalyst.

[0088] Mix polyetheretherketone with the acidified composite catalyst for melt spinning. The fiber filaments are subjected to mixed opening, carding, web laying, needling, and edge cutting and winding to obtain a needle-punched felt. After the fiber filaments are web laid, pre-needling is carried out to form a preliminary embryo felt. The pre-needling depth is 10 mm, and the pre-needling density is 80 needles / cm 2 , and after pre-needling, main needling is carried out through upper and lower main needling machines to reinforce and form a needle-punched felt. The main needling depth is 6 mm, and the main needling density is 1100 needles / cm 2 ; The needle-punched felt is used as the substrate of the composite catalytic filter bag, and the total gram weight is 350 g / m 2 .

[0089] Place the prepared acidified composite catalyst in deionized water, and ultrasonically oscillate (frequency: 100 Hz) for 2 h to prepare a catalyst suspension with a mass concentration of 2%. Immerse the needle-punched felt in the catalyst suspension for 6 h, and then dry it at 80 °C to obtain a needle-punched felt loaded with the catalyst. The catalyst loading amount of the needle-punched felt is 85 g / m 2 .

[0090] Mix PTFE concentrated dispersion (the solid content of the PTFE concentrated dispersion is 60%), the stabilizer sodium dodecyl sulfate, the foaming agent alkyl polyglycoside (APG), and deionized water (the mass ratio of the PTFE concentrated dispersion, the stabilizer, the foaming agent, and deionized water is 1.5:0.05:0.6:97). The mixture is foamed in a stirrer, and the stirrer stirs at a high speed of 3500 r / min for 10 min to obtain a stable foam coating with a foaming ratio of 4:1. Coat the foam coating on the upper and lower surfaces of the needle-punched felt loaded with the catalyst respectively with a scraper (the thickness of the coating on the upper and lower surfaces is 0.5 cm), and then hot-press a PTFE microporous membrane on the upper surface. The gram weight of the PTFE microporous membrane is 3 g / m 2 , the thickness is 12 μm, the pore size is 0.6 μm, and the air permeability is 80 L / m 2 ·s; the hot-pressing temperature is 250 °C, the time is 9 s, and the pressure is 2 MPa to obtain a high-temperature resistant filter material.

[0091] Example 4

[0092] Mix tetrabutyl titanate, acetic acid (concentration 0.9 mol / L), and absolute ethanol with a volume ratio of 1:1.6:4.8, and stir magnetically (rotation speed 500 r / min) for 20 min to obtain a mixed solution. Mix the mixed solution and activated carbon evenly according to a volume ratio of 1:0.8 to obtain a mud material. The mud material is calcined at 950 °C for 4 h in a nitrogen atmosphere, and the calcined product is crushed and passed through a 60-mesh sieve to obtain TiO2 / activated carbon powder.

[0093] Add ammonium metavanadate and cerium nitrate hexahydrate with a mass ratio of 1:0.7 to deionized water at 70 °C, and stir for 4 h to obtain a mixed solution with a mass concentration of 8%. Add the TiO2 / activated carbon powder to the mixed solution (the mass ratio of the TiO2 / activated carbon powder and the mixed solution is 0.6:1) and mix evenly to obtain a mud material. The mud material is calcined at 450 °C for 2 h in a nitrogen atmosphere, and the calcined product is crushed and passed through a 60-mesh sieve to obtain a V2O5-CeO2-TiO2 / activated carbon multi-component composite catalyst.

[0094] Soak the multi-component composite catalyst in 0.1 mol / L sulfuric acid for 4 h for acidification treatment, then wash the composite catalyst with deionized water until the pH value no longer changes, and then dry the composite catalyst in an oven at 100 °C for 12 h to obtain an acidified composite catalyst.

[0095] Mix polyether ether ketone and the acidified composite catalyst for melt spinning. The fiber filaments are subjected to mixed opening, carding, web laying, needling, and edge cutting and winding to obtain a needle-punched felt. After the fiber filaments are web-laid, pre-needling is carried out to form a preliminary embryo felt. The pre-needling depth is 10 mm, and the pre-needling density is 80 needles / cm 2, after pre-needling, it is further subjected to main needling by upper and lower main needling machines to form a needled felt by consolidation. The main needling depth is 6 mm, and the main needling density is 1100 needles / cm 2 ; The needled felt serves as the substrate of the composite catalytic filter bag, with a total grammage of 350 g / m 2 .

[0096] The prepared acidified composite catalyst is placed in deionized water and ultrasonicated (frequency of 100 Hz) for 2 h to obtain a catalyst suspension with a mass concentration of 2%. The needled felt is immersed in the catalyst suspension for 6 h, and then dried at 80 °C to obtain a needled felt loaded with the catalyst. The catalyst loading of the needled felt is 85 g / m 2 .

[0097] The PTFE concentrated dispersion (the solid content of the PTFE concentrated dispersion is 60%), the stabilizer sodium dodecyl sulfate, the foaming agent alkyl polyglycoside (APG), and deionized water are mixed (the mass ratio of the PTFE concentrated dispersion, the stabilizer, the foaming agent, and deionized water is 1.5:0.05:0.6:97). The mixture is foamed in a stirrer, and the stirrer stirs at a high speed of 3500 r / min for 10 min to obtain a stable foam coating with a foaming ratio of 4:1. The foam coating is respectively scraped onto the upper and lower surfaces of the needled felt loaded with the catalyst (the scraping thickness of both the upper and lower surfaces is 0.5 cm), and then a PTFE microporous membrane is hot-pressed on the upper surface. The grammage of the PTFE microporous membrane is 3 g / m 2 , with a thickness of 12 μm, a pore diameter of 0.6 μm, and an air permeability of 80 L / m 2 ·s; The hot-pressing temperature is 250 °C, the time is 9 s, and the pressure is 2 MPa to obtain a high-temperature resistant filter material.

[0098] Example 5

[0099] This example is the same as Example 4, except that: the composite catalyst is acidified by soaking in 0.1 mol / L sulfuric acid for 5 h.

[0100] Example 6

[0101] This example is the same as Example 4, except that: the composite catalyst is acidified by soaking in 0.1 mol / L sulfuric acid for 6 h.

[0102] Comparative Example 1

[0103] This comparative example is the same as Example 4, except that: the mixed solution and activated carbon are mixed evenly at a volume ratio of 1:0.8 and then directly dried at 100 °C, and after drying, it is pulverized and passed through a 60-mesh sieve, omitting the step of high-temperature calcination under a nitrogen atmosphere.

[0104] Comparative Example 2

[0105] This comparative example is the same as Example 4, except that: the mixed solution and activated carbon are mixed evenly at a volume ratio of 1:0.8 and then directly dried at 100 °C, and after drying, it is pulverized and sieved through a 60-mesh sieve, omitting the step of high-temperature calcination in a nitrogen atmosphere; at the same time, the acidification treatment step of the V2O5-CeO2-TiO2 / activated carbon multi-component composite catalyst is omitted.

[0106] The properties of the high-temperature resistant filter materials of the examples and comparative examples were tested.

[0107] The catalytic degradation performance of the high-temperature resistant filter materials prepared in Examples 1 to 6 and Comparative Examples 1 to 2 was tested. The test method was as follows: o-dichlorobenzene with a molecular structure similar to that of dioxin was selected as a substitute for dioxin. A micro-injection pump and a constant-temperature oil bath were connected to the catalytic evaluation device, and the simulated gas mixture composition (volume ratio) was 11% O2 + 89% N2. 20 mL of o-dichlorobenzene was taken with a disposable medical syringe and placed on the micro-injection pump. The needle was connected to the inlet pipe, and a constant-temperature oil bath was placed under the inlet pipe. The temperature was set to 200 °C to convert the liquid o-dichlorobenzene into a gas, so that it could be tested through the catalyst. The test started at 200 °C, and the heating rate was 5 °C / min. After heating at 200 °C, 240 °C, and 280 °C for 20 min each, the gas was collected with an aluminum foil gas collection bag. Then, two syringe needles of gas were extracted from the gas collection bag with a 50 μL micro-syringe and injected into a gas chromatograph for analysis. At the same time, the reference peak areas of o-dichlorobenzene without a catalyst at 200 °C, 240 °C, and 280 °C were tested respectively, and the dioxin removal rate was calculated according to formula (1).

[0108]

[0109] In formula (1), A 基 and A 催 are the reference peak area and the detected peak area after using the catalyst, respectively.

[0110] The removal rates of dioxin by the filter materials of the examples and comparative examples at different temperatures are shown in Table 1.

[0111] Table 1 Removal rates of dioxin by the filter materials of the examples and comparative examples at different temperatures

[0112] Group Removal Rate (200°C) Removal Rate (240°C) Removal Rate (280°C) Example 1 83.5％ 82.7％ 81.8％ Example 2 86.2％ 88.5％ 86.7％ Example 3 87.1％ 88.1％ 87.1％ Example 4 88.1％ 89.6％ 88.8％ Example 5 90.3％ 89.7％ 90.5％ Example 6 92.1％ 91.6％ 90.8％ Comparative Example 1 78.8％ 77.6％ 77.9％ Comparative Example 2 66.7％ 67.8％ 66.3％

[0113] According to the results of Examples 1-6 and Comparative Examples 1-2, it can be seen that the catalytic degradation performance of the high-temperature resistant filter material of the present invention is less affected by temperature. According to the results of Examples 4-6, it can be seen that the catalytic degradation performance of the high-temperature resistant filter material is affected by the acidification time, and the increase of the acidification time can improve the removal rate of dioxin by the material. According to the results of Examples 4-6 and Comparative Examples 1-2, it can be seen that the time of heat treatment and acidification treatment in the preparation process of the high-temperature resistant filter material has a great influence on the catalytic degradation effect of dioxin.

[0114] The filtration performance of the high-temperature resistant filter materials of Examples 1-4 was tested. The test method was as follows: The filtration performance of the samples was tested using an LZC-K1 filter material comprehensive performance test system. The test conditions were based on European Standard EN1822-3. The test flow rate range was 10-100 L / min, the measurement resistance range was 0-1000 Pa, and the test area was 100 cm 2 , and the test dust source was NaCl aerosol. It was found through testing that the highest filtration efficiency of the high-temperature resistant filter material of Example 1 could reach 99.88%, the highest filtration efficiency of the high-temperature resistant filter material of Example 2 could reach 99.78%, the highest filtration efficiency of the high-temperature resistant filter material of Example 3 could reach 99.86%, and the highest filtration efficiency of the high-temperature resistant filter material of Example 4 could reach 99.92%.

[0115] The high-temperature mechanical properties of the high-temperature resistant filter materials of Examples 1-4 were tested. The tensile test at high temperature was carried out according to the standard of normal temperature tensile test. The experimental samples were placed in a testing machine with a high-temperature oven. When the high-temperature oven reached 250 °C, after maintaining the temperature for 10 min, the tensile test was carried out to obtain the high-temperature tensile data.

[0116] It was found through testing that after continuous high-temperature aging at 250 °C, the strength retention rate of the high-temperature resistant filter materials of Examples 1-4 was greater than 90%.

[0117] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a high temperature resistant filter material, characterized in that: The following steps are included: 1) Tetrabutyl titanate, acetic acid, anhydrous ethanol and activated carbon are mixed to obtain a slurry; the slurry is calcined to obtain TiO2 / activated carbon powder; 2) ammonium metavanadate, cerium nitrate hexahydrate and water are mixed to obtain a mixed solution; TiO2 / activated carbon powder is added to the mixed solution to obtain a mud material; the mud material is calcined to obtain a V2O5-CeO2-TiO2 / activated carbon multi-component composite catalyst; 3) acidifying, washing and drying the multi-component composite catalyst in sequence to obtain an acidified composite catalyst; 4) After spinning the organic matter and the acidified composite catalyst, pre-needling and main needling are performed in sequence to obtain a needle-punched felt; 5) subjecting the acidified composite catalyst and water to ultrasonic vibration to obtain a catalyst suspension; immersing the needle-punched felt in the catalyst suspension and drying it to obtain a catalyst-loaded needle-punched felt; 6) Mixing the polytetrafluoroethylene dispersion, the stabilizer, the foaming agent and water and foaming them to obtain a foam coating; 7) Scraping the foam coating on the upper and lower surfaces of the catalyst-loaded needle felt, and then hot-pressing a polytetrafluoroethylene microporous membrane on the upper surface of the needle felt to obtain a high temperature resistant filter material; Step 2) The calcination temperature is 400-450° C. and the calcination time is 2-4 hours.

2. The preparation method according to claim 1, characterized in that: Step 1) the volume ratio of tetrabutyl titanate, acetic acid and anhydrous ethanol is 1:1.2-2:4.4-5.5, and the volume ratio of the total volume of tetrabutyl titanate, acetic acid and anhydrous ethanol to the volume ratio of activated carbon is 1:0.8-1.2; The calcination temperature is 900-950° C., the calcination time is 2-4 hours, and the calcination atmosphere is a nitrogen atmosphere.

3. The preparation method according to claim 1 or 2, characterized in that: Step 2) the mass ratio of the ammonium metavanadate to the cerium nitrate hexahydrate is 1:0.6-0.8, and the mass concentration of the mixed solution is 2-10%; The mixing temperature is 60-80° C., the mixing time is 3-4 hours, and the calcination atmosphere is a nitrogen atmosphere.

4. The preparation method according to claim 3, characterized in that: Step 3) The acidification reagent is sulfuric acid, the concentration of sulfuric acid is 0.08-0.12 mol / L, the acidification time is 4-6 hours, the washing reagent is water, and the pH value of the multi-component composite catalyst no longer changes; the drying temperature is 90-105°C, and the drying time is 12-18 hours.

5. The preparation method according to claim 4, characterized in that: Step 4) the mass ratio of the organic matter to the acidified composite catalyst is 10-30:70-90, and the organic matter comprises one or more of polyetheretherketone, polytetrafluoroethylene and polyphenylene sulfide; The depth of the pre-needling is 10-14 mm, and the density is 70-140 needles / cm 2 The main acupuncture depth is 6~12mm, and the density is 1000~1500 needles / cm 2 .

6. The preparation method according to claim 4 or 5, characterized in that: Step 5) The mass concentration of the catalyst suspension is 1-8%, the immersion time is 6-8 hours, and the drying temperature is 80-100°C; The catalyst loading of the needle felt is 80-120 g / m 2 ; The total weight of needle felt is 200~600g / m 2 .

7. The preparation method according to claim 6, characterized in that: Step 6) The solid content of the polytetrafluoroethylene dispersion is 57-63%; the mass ratio of the polytetrafluoroethylene dispersion, the stabilizer, the foaming agent and water is 1.5-2: 0.05-0.1: 0.6-1: 97-98; The foaming time is 10-15 minutes, and stirring is performed during the foaming process at a stirring rate of 3000-5000 r / min; the foaming ratio of the foam coating is 4-6:1; The foaming agent is sodium cocoylamphoacetate or alkyl glucoside, and the stabilizer is Tween 80 or sodium lauryl sulfate.

8. The preparation method according to claim 7, characterized in that: Step 7) the coating thickness is 0.4-0.6 cm; the hot pressing temperature is 200-300° C., the hot pressing time is 8-10 s, and the hot pressing pressure is 1-3 MPa; The weight of the polytetrafluoroethylene microporous membrane is 3-4 g / m 2 , thickness is 10~15μm, pore size is 0.6~0.8μm, air permeability is 70~100L / m 2 ·s.

9. The high temperature resistant filter material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the high temperature resistant filter material according to claim 9 in removing dioxins.

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