KR20100114728A - Ceramic filter catalyst coating apparatus and catalyst coating method having the same - Google Patents

Abstract

PURPOSE: A ceramic filter catalyst-coating apparatus and a method thereof are provided to effectively attach a catalyst to a sheet-type ceramic filter, and to prevent the concentration gradient of a coating solution during a drying process when coating the ceramic filter. CONSTITUTION: A ceramic filter catalyst-coating apparatus comprises the following: a driving motor(10); a grip unit(20) connected to the driving motor to fix a ceramic filter; a catalyst solution tank(30) for storing a catalyst solution to dip the ceramic filter fixed to the grip unit; and a controller(C) varying the rotation amount of driving motor by the kind of the catalyst solution.

Description

Ceramic filter catalyst coating apparatus and catalyst coating method using the same {Ceramic filter catalyst coating apparatus and catalyst coating method having the same}

The present invention relates to a method for effectively producing a catalyst filter capable of simultaneously removing dust and nitrogen oxides, which are pollutants generated in ships, automobiles, incinerators, and various industrial processes. The present invention relates to an apparatus for coating an oxide reduction catalyst and a catalyst coating method using the same.

In general, the catalyst filter is attached to the filter that can be used at high temperatures of the ceramic or metal material having a dust collection function, it is configured to process the nitrogen oxide together with the dust at the same time.

Emissions are mainly classified into dust, sulfur oxides, nitrogen oxides, chlorine compounds, and heavy metal gases. Although technologies for treating these materials individually have already been commercialized, the need for complex treatment technology has been emphasized in order to increase the energy utilization of the gas to be treated and to develop a more environmentally friendly and economical treatment system.

Among them, Babcock & SO _x -NO _x -RO _x Box (SNRB) process that can efficiently process SO _x , dust and NO _x in exhaust gas by using catalyst filter that can perform dust and dust collection at the same time. Introduced by Wilcok. EP 0 268 353 A1; US 4,309,386. This step is the selective catalytic reduction (SCR) function is injected into the SO _x absorbent and ammonia as the reducing agent in the catalyst filter dust collector shear given after the SO _x absorbent and system for removing particulates and NO _x at the same time.

Catalysts applied to the SCR reaction include metal oxides V ₂ O ₅ , Fe ₂ O ₃ , CuO, Cr ₂ O ₃ , NiO, CeO ₂ , Pr ₆ O ₁₁ , Nd ₂ O ₃ , Gd ₂ O ₃ , Yb ₂ O ₃ and the like are known. These catalysts are coated on a honeycomb or monolith support such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , or the like. Among them, V ₂ O ₅ -WO ₃ -TiO ₂ catalyst is widely used in commercial processes. In particular, WO ₃ is known to have a large role in the regeneration of the Bronsted and Lewis acid sites of the catalyst and to increase the activity of the catalyst by minimizing the effect of deactivation by SO ₂ . Therefore, the V ₂ O ₅ -WO ₃ / TiO ₂ catalyst not only shows 90% or more of NO _x removal efficiency, but also has good durability against SO ₂ which affects the reaction. The V ₂ O ₅ -TiO ₂ catalyst is a high temperature catalyst and shows excellent nitrogen oxide removal at 300 to 400, but has a low efficiency at low temperatures. In order to overcome these disadvantages, MnOx, MoO ₂ , CeO ₂ , SnO ₂ , ZrO _2, etc. have been studied as catalysts having the same efficiency and activity even at low temperatures.

In addition, Pt, Pd, Ru and the like as a noble metal catalyst for low temperature SCR reaction. The precious metal fast catalyst shows excellent performance at low temperatures, but promotes oxidation of ammonia as a reducing agent at high temperatures, and has a disadvantage in that catalytic activity is lowered by sulfur oxides contained in exhaust gas. As zeolite-based catalysts, H-ZSM-5, mordenite, Y-Zeolite, silicatlite, and the like are utilized, and a catalyst is attached by attaching a catalyst to the zeolite itself or exchanging metal ions. As described above, about 1000 kinds of ammonia-based SCR catalysts have been reported in combination of catalysts such as metal and nonmetal oxides, various nonmetal oxides, and zeolites.

The catalysts are mainly attached to honeycomb or monolithic ceramic filters and used for treating nitrogen oxides in exhaust gas. However, the existing honeycomb or monolith has no dust collection function. Therefore, the dust is removed from the electric dust collector or filter bag dust collector which is operated at a medium and low temperature of about 150 ° C at the front end, and then heated to the SCR reaction temperature and then SCR at a high temperature of 300-400 ° C. The process of advancing the reaction is mainly followed. Therefore, it is highly desirable to use a catalyst filter that can simultaneously carry out dust collection and SCR reactions in order to reduce the processing cost, equipment operation cost, and energy loss associated with using a multi-stage device.

In order to develop a catalyst filter, a method of effectively attaching a previously developed high-performance catalyst to a dust collecting filter is important. US Patent No. 4,220,633 introduced a method for producing a catalyst filter by spray coating a noble metal or metal oxide catalyst on the bag filter (bag filter). Glass, metal and ceramic fibers were used as filter materials. U.S. Patent No. 4,732,879 prepared a catalyst filter using an immersing method to immerse a glass fiber cloth in a sol-gel solution containing various components of SCR catalyst. US Patent No. 5,051,391 prepared a catalyst filter for treating flue gas by dipping a glass fiber filter cloth in a slurry of a catalyst component. U.S. Patent Nos. 5,620,669 and 5,843,390 introduced a method for producing a porous catalyst filter by mixing SCR catalyst with expanded polytetrafluoroethylene (e-PTFE) composite fiber and then making it with felt like e-PTFE. Korean Patent No. 2002-0030991 proposed a method of coating a bag filter by spraying the SCR catalyst into a slurry.

The catalytic filter fixed to the bag filter type dust collection filter introduced above is limited to the use temperature of 250 ° C. or less, and the bag filter is difficult to meet the ultra-precision dust collection efficiency because the dust collection efficiency is low when the amount of processing gas is large. Therefore, in order to realize high temperature operation and ultra-precision dust collection, a catalyst filter manufactured by using a molded ceramic filter is required. Coating of catalysts on ceramic shaped bodies, especially honeycomb through-flow filters, has been developed in various ways for the production of catalytic filters for diesel vehicle exhaust gas purification or combustion. As a soot filter for a diesel vehicle, a honeycomb type filter is mainly used. In Patent No. 10-2005-0034983, in order to prepare a diesel particulate catalyst filter, a method of fixing a catalyst to a filter by preparing a slurry with particles of catalyst components and dipping the filter therein (immersion method) is proposed. Patent No. 10-2006-005630 discloses a method for producing a catalyst filter in which a catalyst component is prepared in a colloidal state and an organic solvent such as polyethylene glycol (PEG) and a polymer material are adjusted to adjust the size of particles to coat the catalyst well in the micropores of the filter. Presented. The method of immobilizing the catalyst on a honeycomb well-flow filter by dip coating has been introduced in WO 01l12320 A1 and US 2004l0258594 A1.

As described above, in the method of immobilizing the catalyst on the ceramic compact, a deep coating method in which a filter is immersed in a sol-gel colloidal state in order to disperse the catalyst particles to the micropores of the filter is commonly used. Has been. In this case, satisfactory dispersion is difficult due to the aggregation of catalyst particles during the treatment even when the polymer imprinting method is used using a dispersant or a polymer material. In addition, when the catalyst filter is manufactured by dipping the catalyst particles prepared in advance in a slurry state in order to increase the dispersion of the catalyst particles, it is difficult to disperse the catalyst particles in the fine pores of the filter.

In particular, in the case of a sheet-type ceramic filter having a thickness of the filter and the catalyst to be attached to the surface of the inner pores of the filter, it is difficult to play a role as a catalyst filter in a technique in which only the surface is coated, such as spray coating. Therefore, there is a need for an effective technique for dispersing the catalyst particles to the pores inside the filter.

The present invention has been made in view of the above problems, it is possible to uniformly disperse the catalyst particles, ceramic filter catalyst coating apparatus and catalyst coating method using the same that can disperse the catalyst particles to the inner pores of the sheet-type ceramic filter The purpose is to provide.

Ceramic filter catalyst coating apparatus according to the present invention for solving the above problems, the drive motor; A grip unit fixed to a ceramic filter and connected to the driving motor; A catalyst solution tank in which a catalyst solution is stored and the ceramic filter fixed to the grip unit is submerged; And a controller for varying the rotation speed of the driving motor according to the type of the catalyst solution.

The ceramic filter catalyst coating apparatus may further include a heating unit for applying heat to the ceramic filter coated with the catalyst solution.

The control unit, it is preferable to adjust the rotational speed of the drive motor to 80 ~ 120rpm in the coating step and the drying step of the ceramic filter.

The grip unit includes a cell cover supporting both ends of the ceramic filter; And fastening means for fastening the ceramic filter and the cell cover.

Ceramic filter catalyst coating apparatus according to the present invention may further include a lifting unit for adjusting the height of the catalyst solution tank.

Ceramic filter catalyst coating method according to the present invention comprises the steps of washing the ceramic filter to remove foreign matter; Removing the organic material using the washed ceramic filter using either acid or alkali; Ultrasonic cleaning the ceramic filter from which the organic material has been removed; Drying the washed ceramic filter; Fixing the dried ceramic filter to a ceramic filter catalyst coating apparatus; Injecting a first catalyst solution into the catalyst tank and performing a first catalyst coating on the surface while rotating the fixed ceramic filter; Removing the first catalyst solution and drying the coated ceramic filter while rotating; Injecting a second catalyst solution into the catalyst tank and performing a second catalyst coating on the surface while rotating the ceramic filter coated with the first catalyst; Removing the second catalyst solution and drying the coated ceramic filter while rotating; And firing the ceramic filter coated with the first and second catalysts at a predetermined temperature.

The first and second catalyst coating step and the drying step is preferably performed while rotating at 80 ~ 120rpm.

According to a first embodiment, the first catalyst coating step, using the first catalyst solution stirred to a concentration of 7wt% by adding TiO ₂ powder to 35% HCl aqueous solution of PH 1.4, the second catalyst In the coating step, it is preferable to use the second catalyst solution in which NH ₄ VO ₃ and (NH ₄ ) 6 H ₂ W ₁₂ O ₄₀ .xH ₂ O precursor are dissolved in an oxalic acid solution.

In the first catalyst solution drying step, the heater is heated and evaporated to dryness at a temperature of 60 to 80 ° C., and then dried at 110 to 130 ° C. for 2 hours or more.

The firing step is preferably baked for 5 hours at 400 ~ 500 ℃.

According to a second embodiment, the first catalyst coating step uses the first catalyst solution stirred by adding TiO ₂ powder to a 35% HCl aqueous solution of pH 1.4 to a concentration of 7wt%, and the second catalyst The coating step was performed by using a second catalyst solution in which NH ₄ VO ₃ and (NH ₄ ) 6 H ₂ W ₁₂ O ₄₀ .xH ₂ O precursor and (Mn (NO ₃ ) ₂ .xH ₂ O) were dissolved in aqueous oxalic acid solution. It is good.

According to a third embodiment, in the first catalyst coating step, the TiO ₂ powder is added to a 35% HCl aqueous solution having a pH of 1.4 and the first catalyst solution is stirred to have a concentration of 7 wt%, and the second catalyst In the coating step, it is preferable to use a second catalyst solution in which NH ₄ VO ₃ and (NH ₄ ) 6 H ₂ W ₁₂ O ₄₀ .xH ₂ O precursor and Cl ₄ H ₈ N ₂ P ₅ are dissolved in an oxalic acid solution.

According to the present invention as described above, after undercoating TiO ₂ , the main carrier of the sheet-shaped ceramic filter, the catalyst component is dissolved in an aqueous solution to support the undercoated filter, followed by drying and baking while rotating at a low speed. The catalyst can be effectively attached to the filter.

In addition, when TiO ₂ is coated on the ceramic filter by immersing or dip coating, the concentration gradient caused by the coating liquid flowing down in the axial direction can be overcome.

Hereinafter, a ceramic filter catalyst coating apparatus and a catalyst coating method using the same according to a preferred embodiment of the present invention will be described with the accompanying drawings.

In the ceramic filter catalyst coating apparatus according to the present invention, the catalyst is coated on the ceramic filter by gel dipping based on a process of supporting, molding and drying the nonwoven fabric of the ceramic mixture.

The ceramic filter can be manufactured in various forms, and can be manufactured in a structure having high porosity. The gel dipping method through non-woven fabric precipitation is inexpensive, and the filter can be manufactured in various shapes according to the desired shape. There is an advantage.

The nonwoven fabric has a supporting function of forming the basic shape of the ceramic mixture during the manufacturing process of the ceramic filter, and is used with a pore-forming agent such as activated carbon and wood powder to form micropores of the hetero-section tunnel structure of the ceramic filter. Here, the role of the pore-forming agent can open pores that connect all the pores with each other to maximize the air permeability of the ceramic filter. In addition, it is easy to synthesize, add, and mix various functional materials during the mixing process of raw materials.

The ceramic filter configured as described above may be used as a dust collecting filter of various dust collecting equipments, and by coating a catalyst and an adsorbent on the inside or outside of the ceramic filter, a catalyst carrier which is an air purifier of automobile exhaust gas, a volatile organic compound processing device in an air cleaner, and It can be used in combination in the exhaust gas treatment device. When the pollution gas including dust passes through the catalyst filter, dust is first removed from the outer wall of the catalyst filter, and nitrogen oxide is removed from the inner catalyst layer when passing through the filter.

1 schematically shows a ceramic filter catalyst coating apparatus according to the present invention.

The ceramic filter catalyst coating apparatus according to the present invention includes a drive motor 10, a grip unit 20, a catalyst solution tank 30, and a heating unit 40.

The driving motor 10 is connected to the grip unit 20, the rotating shaft 11, and the chuck 12 to rotate the grip unit 20 at a low speed between 80 and 120 rpm. It is preferable to rotate at a speed of about 100 rpm.

As shown in FIG. 2, the grip unit 20 fixes both ends of the ceramic filter 21, and one end thereof is connected to the driving motor 10 so as to interlock with the rotation of the driving motor 10. Rotate

The grip unit 20 may include a cell cover 22 and 23 for supporting both ends of the ceramic filter 21, and a fastening member for fastening the cell cover 22 and 23 to the ceramic filter 21. 24). The fastening means 24 may use a bolt / nut or the like.

The catalyst solution tank 30 has the catalyst solution 35 stored therein, and the level of the catalyst solution is adjusted so that the ceramic filter 21 fixed to the grip unit 20 can be submerged by about 50 to 60%. The catalyst solution tank 30 has a catalyst solution inlet tube 31 for injecting the catalyst solution 35 and a catalyst solution discharge tube 32 for discharging the catalyst solution 35 stored in the catalyst solution tank 30 to the outside. Prepared. By using the catalyst solution inlet pipe 31 and the discharge pipe 32, it is possible to inject and discharge different types of catalyst solution in stages.

The heating unit 40 is installed in the catalyst solution tank to heat / dry the ceramic filter 21 coated with the catalyst solution 35.

The control unit (C) is for controlling the rotational speed of the drive motor 10, so as to vary the rotational speed of the drive motor 10 according to the type of catalyst solution supplied to the catalyst solution tank (30). do.

On the other hand, the lifting unit 50 for adjusting the height of the catalyst solution tank 30 may be further provided, by using the lifting unit 50, the ceramic filter 21 to the grip unit 20 more easily Can be mounted and detached.

Hereinafter, a ceramic filter catalyst coating method according to the present invention will be described.

A method of manufacturing the catalyst filter by the rotary coating method will be described with the flowchart of FIG. 4.

First, the foreign matter on the surface of the ceramic filter 21 is removed using water or the like (S10).

The washed ceramic filter 21 is again, using a dilute caustic soda or dilute nitric acid aqueous solution, to remove the organic material attached to the ceramic filter 21 (S20), again washed with water and dried (S30) .

The dried ceramic filter 21 is fixed to the grip unit 20 and mounted in the catalyst coating apparatus according to the present invention (S40).

Then, the first catalyst solution in which the titania particles are dispersed is injected into the catalyst solution tank 30 so that the ceramic filter 21 can be submerged about half.

The first catalyst solution was prepared so that the concentration was 7 wt.% By adding TiO ₂ Degussa P25 powder to 35% HCl aqueous solution of PH 1.4, and stirred for about 30 minutes to form a TiO ₂ solution.

And, while rotating the drive motor 10 at a low speed of about 100rpm, the ceramic filter 21 is first coated. At this time, the TiO ₂ aqueous solution, which is the first coating solution, is continuously coated for about 30 minutes so as to completely fill the pores in the filter (S50).

The primary coated ceramic filter 21 is dried by using the heat of the heating unit 40. At this time, the drive motor 10 allows the ceramic filter 21 to be evenly dried while continuing the low speed rotation.

As such, when the ceramic filter 21 is rotated and dried, the phenomenon in which the catalyst is not uniformly coated due to the gravity of the solution in the drying of the conventional deep coating process can be effectively improved. Not only the catalyst particles are attached to the micropores of (21), but the catalyst is evenly attached to all the pores of the filter.

In this drying process, the first first catalyst solution-coated ceramic filter 21 is rotated at about 60 rpm, and the external heat of about 50 to 70 ° C. is applied to evaporate most of the water, followed by complete heating at a temperature of 150 to 250 ° C. Drying is to stabilize the coating surface (S60).

When the ceramic filter 21 coated with the first catalyst solution is dried by the above process, the second catalyst solution is secondly coated. The coating is coated while rotating at a low speed by using the driving motor 10, as described above, the second catalyst solution may be variously configured according to the conditions of use. For example, a high temperature catalyst at 300-350 ° C. typically has a composition in which V ₂ O ₅ —WO ₃ is attached to TiO ₂ . As the low-temperature catalyst around 200 ° C, the composition of the catalyst containing a promoter such as Pt and MnOx is effective (S70).

The ceramic filter 21 to which the second catalyst is attached performs the same drying process as the above drying process (S80), and calcinates for 5 hours at a temperature of about 450-500 ° C to finally complete the catalyst coating (S90). ).

On the other hand, in step S70, the second catalyst solution used may be configured in various ways depending on the conditions of use of the ceramic filter.

When a second catalyst solution is used as a catalyst for high temperature and a V ₂ O ₅ -WO ₃ / TiO ₂ / SiC catalyst filter is prepared, the second catalyst solution is an aqueous oxalic acid solution in which 60 g of oxalic acid is mixed with 3000 ml of distilled water (about Ammonium vanadate (V) (NH ₄ VO ₃ ) and Ammonium metatungstate hydrate ((NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ XH ₂ O) precursors were dissolved in pH = 1.2). V ₂ O ₅ is from about 1 wt% of TiO ₂ amount, WO ₃ is 8 wt% of TiO ₂ loading.

The prepared filter was subjected to a performance test at a filtration rate of 2 cm / s in a nitrogen atmosphere of 500 ppm NO, 500 ppm NH ₃ and O ₂ 7%. N ₂ selectivity above% was shown.

When the MnO ₂ -V ₂ O ₅ -WO ₃ / TiO ₂ / SiC catalyst filter was prepared using the second catalyst solution as a low temperature catalyst, Ammonium vanadate (V) (NH) was added to an aqueous solution of oxalic acid (about pH = 1.2). ₄ VO ₃ ) and Ammonium metatungstate hydrate ((NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ XH ₂ O) and Manganese (II) nitrate hydrate (Mn (NO ₃ ) ₂ XH ₂ O) precursors Coating the catalyst. The contents of V ₂ O ₅ and WO ₃ are the same as those of the V ₂ O ₅ -WO ₃ / TiO ₂ catalyst, and the content of MnO ₂ is 50% of the content of V ₂ O ₅ in order to find the optimal activity. adjusted to wt%.

The manufactured filter was tested at a rate of 2 cm / s at a nitrogen atmosphere of 500 ppm NO, 500 ppm NH ₃ , and O ₂ 7%. N2 selectivity greater than% was shown.

When a Pt-V ₂ O ₅ -WO ₃ / TiO ₂ / SiC catalyst filter was prepared using the second catalyst solution as a low temperature catalyst, the solution was added to Ammonium vanadate (V) (NH ₄ ) in an aqueous solution of oxalic acid (about pH = 1.2). VO ₃ ) and Ammonium metatungstate hydrate ((NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ XH ₂ O), and Ammonium tetrachloroplatinate (II) (Cl ₄ H ₈ N ₂ Pt) precursors were dissolved to coat the catalyst with the above process. do.

The prepared filter was subjected to a performance test at a filtration rate of 2 cm / s in a nitrogen atmosphere of 500 ppm NO, 500 ppm NH ₃ and O ₂ 7%. N ₂ selectivity above 95%.

According to the ceramic filter catalyst coating apparatus and catalyst coating method according to the present invention as described above, it is possible to maximize the effect of uniformly attaching the catalyst by fixing a variety of SCR catalyst to the ceramic filter by the rotation method. The filter manufactured in this way has better performance than the conventional Dipping method or Spray method and is economical because the manufacturing process is simple.

1 is a schematic view of a ceramic filter catalyst coating apparatus according to the present invention,

2 is a view illustrating a state in which the ceramic filter of FIG. 1 is coupled to a grip unit;

3 is a front view of Figure 1,

Figure 4 is a flow chart illustrating a ceramic filter catalyst coating method according to the present invention.

<Description of the symbols for the main parts of the drawings>

10; Drive motor 11; Axis of rotation

12; Chuck 20; Grip unit

30; Catalyst solution tank 40; Heater

50; Hoist

Claims (12)

Drive motor; A grip unit fixed to a ceramic filter and connected to the driving motor; A catalyst solution tank in which a catalyst solution is stored and the ceramic filter fixed to the grip unit is submerged; And And a controller for varying the rotation speed of the driving motor according to the type of the catalyst solution. The method of claim 1, The ceramic filter catalyst coating apparatus further comprises a heating unit for applying heat to the ceramic filter coated catalyst solution. The method of claim 2, wherein the control unit, Ceramic filter catalyst coating apparatus, characterized in that for controlling the rotational speed of the drive motor to 80 ~ 120rpm in the coating step and the drying step of the ceramic filter. The method of claim 1, wherein the grip unit, A cell cover supporting both ends of the ceramic filter; And Ceramic filter catalyst coating apparatus comprising a; fastening means for fastening the ceramic filter and the cell cover. The method of claim 1, Ceramic filter catalyst coating apparatus further comprises a lifting unit for adjusting the height of the catalyst solution tank. Washing the ceramic filter to remove foreign substances; Removing the organic material using the washed ceramic filter using either acid or alkali; Ultrasonic cleaning the ceramic filter from which the organic material has been removed; Drying the washed ceramic filter; Fixing the dried ceramic filter to a ceramic filter catalyst coating apparatus; Injecting a first catalyst solution into the catalyst tank and performing a first catalyst coating on the surface while rotating the fixed ceramic filter; Removing the first catalyst solution and drying the coated ceramic filter while rotating; Injecting a second catalyst solution into the catalyst tank and performing a second catalyst coating on the surface while rotating the ceramic filter coated with the first catalyst; Removing the second catalyst solution and drying the coated ceramic filter while rotating; And Calcining the ceramic filter coated with the first and second catalyst at a predetermined temperature; ceramic filter catalyst coating method comprising a. The method of claim 6, The first and second catalyst coating step and the drying step, the ceramic filter catalyst coating method, characterized in that proceeding while rotating at 80 ~ 120rpm. The method of claim 6, In the first catalyst coating step, the TiO ₂ powder was added to 35% HCl aqueous solution having a pH of 1.4, and the first catalyst solution was stirred to have a concentration of 7 wt%. The second catalyst coating step is a ceramic filter catalyst coating, characterized in that using the second catalyst solution dissolved in NH ₄ VO ₃ and (NH ₄ ) 6 H ₂ W ₁₂ O ₄₀ · xH ₂ O precursor in oxalic acid aqueous solution. Way. The method of claim 6, The first catalyst solution drying step is a ceramic filter catalyst coating method characterized in that the heater is heated to a temperature of 60 ~ 80 ℃ evaporated to dry, and then dried at 110 ~ 130 ℃ for 2 hours or more. The method of claim 6, wherein the firing step, Ceramic filter catalyst coating method, characterized in that baked for 5 hours at 400 ~ 500 ℃. The method of claim 6, In the first catalyst coating step, the TiO ₂ powder was added to 35% HCl aqueous solution having a pH of 1.4, and the first catalyst solution was stirred to have a concentration of 7 wt%. The second catalyst coating step is a second catalyst in which NH ₄ VO ₃ and (NH ₄ ) 6 H ₂ W ₁₂ O ₄₀ .xH ₂ O precursor and (Mn (NO ₃ ) ₂ .xH ₂ O) are dissolved in an oxalic acid solution. Ceramic filter catalyst coating method characterized in that the solution was used. The method of claim 6, In the first catalyst coating step, the TiO ₂ powder was added to 35% HCl aqueous solution having a pH of 1.4, and the first catalyst solution was stirred to have a concentration of 7 wt%. The second catalyst coating step, using a second catalyst solution in which NH ₄ VO ₃ and (NH ₄ ) 6H ₂ W ₁₂ O ₄₀ · xH ₂ O precursor and Cl ₄ H ₈ N ₂ P ₅ dissolved in aqueous oxalic acid solution. Ceramic filter catalyst coating method characterized in that.

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