CN101757902A - Method for preparing composite photocatalyst containing activated carbon coating - Google Patents

Abstract

The invention discloses a preparation method of a composite photocatalyst containing activated carbon coating. The method is to attach activated carbon as a coating to a foam material substrate to form an activated carbon coating material, and use the activated carbon coating material as a carrier to load titanium dioxide , wherein the weight percentage of each component is as follows: the active component of titanium dioxide is 1-10%, the active carbon coating is 4-15%, and the rest is a foam material matrix. The method of the invention uses the activated carbon coating material as the photocatalyst carrier, which can effectively improve the dispersibility of the active components of titanium dioxide, overcome the shortcomings of existing activated carbon materials such as loose structure and low strength, and improve the transmission of light in the system and the transmission of pollutants to the catalyst The surface mass transfer process can greatly extend the service life of activated carbon.

Description

A kind of preparation method of composite photocatalyst containing active carbon coating

technical field

The invention relates to a preparation method of a photocatalyst with semiconductor titanium dioxide (TiO ₂ ) as an active component. The catalyst is especially suitable for purifying indoor air.

Background technique

In recent years, with the extensive use of indoor building decoration materials and household chemicals, indoor air pollution has attracted more and more attention. Surveys show that the concentration of organic matter in indoor air is higher than outdoor, even higher than in industrial areas. At present, hundreds of organic substances have been identified from indoor air, some of which are carcinogens. Coatings, adhesives, paints, plywood, floor leather, wallpaper, etc. used in living rooms and offices can release volatile organic compounds into the air, causing indoor pollution. The research results on the main indoor gas pollutants such as formaldehyde and toluene show that titanium dioxide (TiO ₂ ) photocatalytic oxidation technology has unique advantages in treating such refractory organic pollutants. However, the traditional TiO ₂ photocatalytic technology has problems such as large power consumption, difficulty in catalyst recovery, and low efficiency, which limit its industrial application. Therefore, the development and research of high-efficiency _TiO2 photocatalysts has become one of the most active research fields at home and abroad.

Catalyst loading is an effective way to solve the separation and recovery of suspension phase catalysts, which can overcome the characteristics of suspension phase catalysts such as poor stability and easy poisoning. In the process of loading _TiO2 , the structure of the carrier determines the light transfer process in the system and the mass transfer process of the material to the catalyst surface, which also determines the design of the photocatalytic reactor and the efficiency of the photocatalytic system. A large number of studies have found that activated carbon can enrich the target pollutants in the reaction system to the surface of the catalyst, and create a substrate-rich environment on the surface of _TiO2 , thereby increasing the degradation rate. ₂ surface migration, TiO ₂ degrades the organic matter on the surface of the activated carbon and enables the in-situ regeneration of the carrier. This synergistic effect further improves the photocatalytic activity of the composite catalyst. Therefore, immobilizing _TiO2 on activated carbon can not only improve the efficiency of the catalyst, but also solve the problem of catalyst separation and recovery. The Chinese patent application with the publication number CN101244383A "A preparation method of activated carbon-supported titanium dioxide photocatalyst" uses activated carbon with a particle size of 50-100 mesh as a carrier to support _TiO2 to prepare a photocatalyst for the degradation of organic pollutants. Because what this invention uses is the activated carbon after commercial activated carbon is crushed, the particle size is too small, the preparation process easily causes _TiO2 particle agglomeration, and the separation and recovery process is relatively complicated, and separation after use is also easy to cause material loss. The publication number is CN

The Chinese patent application of 1695797A "Preparation method of activated carbon-supported titanium dioxide photocatalyst" adopts chemical vapor deposition method to load _TiO2 on the activated carbon carrier with a particle size of 40-60 mesh for photocatalytic degradation of organic pollutants. The particle size of the activated carbon used in this invention is too small, so when it is used in a packed bed, there is a large bed pressure drop and uneven light distribution; when it is used in a suspended bed, it is easy to wear and pulverize, and it is difficult to apply it to the gas phase. The Chinese patent application with the publication number CN 1803291A "a titanium dioxide/activated carbon fiber photocatalyst and its preparation method and its application in air purification" uses activated carbon fiber as a carrier to load _TiO2 to make a supported photocatalyst. Since the fiber is a non-rigid material , is easy to deform and break in the system, and it is also easy to cause the loaded TiO ₂ to fall off, which affects its scale-up application to a certain extent.

Ceramic materials have the characteristics of high mechanical strength, shock resistance, high temperature resistance, and corrosion resistance. Combining ceramics and activated carbon can make this composite material have the comprehensive advantages of both. The U.S. Patent "Activated Carbon and Its Preparation Method" with the publication number US 4082661 uses shaped porous ceramics with a pore size distribution of 1,000 to 70,000 angstroms as a carrier to impregnate resin, and is used in the field of high-purity filtration after carbonization and activation. The macropore diameter of the formed porous ceramics used in this invention is too small, and the resin impregnated in the pores is activated by carbonization to obtain a smaller macropore diameter, which increases the adsorption resistance of the activated carbon inside the ceramic-activated carbon body and hinders the fluid medium from interacting with the ceramic-activated carbon body. The mass transfer process between the activated carbons inside the activated carbon body makes the activated carbons inside the material not fully utilized and is not suitable for photocatalyst carriers.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a preparation method for a composite photocatalyst containing activated carbon coating, which uses activated carbon coating material as a photocatalyst carrier, which can effectively improve the dispersion of titanium dioxide active components It overcomes the disadvantages of loose structure and low strength of existing activated carbon materials, and improves the mass transfer process of light in the system and pollutants to the surface of the catalyst.

In order to solve the above-mentioned technical problems, a kind of preparation method of the composite photocatalyst containing activated carbon coating of the present invention is that activated carbon is attached as a coating on the foam material substrate to form an activated carbon coating material, and the activated carbon coating material is used as a carrier load Titanium dioxide, wherein the weight percentage of each component is as follows: the active component of titanium dioxide is 1-10%, the active carbon coating is 4-15%, and the rest is a foam material matrix.

In the preparation method of the above-mentioned composite photocatalyst containing activated carbon coating, when the activated carbon coating material is used as the carrier to support titanium dioxide, the titanium dioxide sol is loaded on the activated carbon coating material carrier by the impregnation method, and then calcined at a high temperature to obtain , the preparation steps are as follows:

1) Dissolve titanium alkoxide in alcohol under vigorous stirring, add a certain amount of inhibitor and surfactant, slowly add a mixture of water, alcohol and acid, and continue stirring; titanium alkoxide and inhibitor, alcohol, water The volume ratio is 6～8: 1: 16～25: 0.75～1.5, the addition amount of surfactant is 1～3% of the total weight of titanium dioxide sol, stirs and mixes, obtains uniform, stable and transparent _TiO sol;

2) Immerse the active carbon coating material carrier in the titanium dioxide sol for 2-4 hours, take it out and place it in a closed container for gel aging for 12-24 hours, then put it in a drying oven and dry it at a temperature of 80-110°C for 2-2 hours. 4h; place the dried carrier in a resistance furnace in an oxygen-free environment from room temperature to 450-650°C, keep it warm for 40-90min; then cool down to room temperature with the furnace.

The above-mentioned preparation method of a composite photocatalyst containing activated carbon coating, the titanium alkoxide used when preparing the titanium dioxide sol is tetrabutyl titanate; the alcohol is ethanol, isopropanol, n-butanol One or a mixture of two or more; the acid is one or a mixture of two or more of nitric acid, sulfuric acid, and hydrochloric acid; the inhibitor is one of acetylacetone, glacial acetic acid, and diethanolamine; the surface The active agent is one or a mixture of two or more of polyethylene glycol, polyvinyl alcohol, and nonylphenol polyoxyethylene ether.

The preparation method of the above-mentioned composite photocatalyst containing activated carbon coating, the activated carbon coating attached to the foam material is prepared by thermosetting resin, and the thermosetting resin containing solvent is coated on the inner and outer surfaces of the foam material by dipping process, The thermosetting resin is treated as a carbon precursor through a curing process, a carbonization process, an activation process and a cleaning process to obtain an activated carbon coating attached to the foam ceramics, and the activated carbon coating is 5% of the total mass of the activated carbon coating material. ~20%, the coating thickness is 0.1 ~ 1mm, and the surface area of the activated carbon coating is 800 ~ 1400m ² /g, the preparation process is as follows:

1) Impregnation process: after ultrasonic cleaning, the foam material matrix is dried at 105±5°C for 4 to 8 hours, placed in a jacketed container filled with thermosetting resin, and immersed in the impregnation solution for 4 to 16 hours. Hours, there is warm water circulation in the jacket of the container used for impregnation, and the temperature of the warm water is 20-70°C; the foam material matrix impregnated with thermosetting resin is taken out from the container, and the excess thermosetting resin is removed by air blowing or centrifuge;

2) Curing process: put the foam material matrix impregnated with thermosetting resin at room temperature for 6-12 hours, then put it into an oven for curing, start at 70°C, increase the temperature by 1-4°C per minute, and keep it warm at 150°C 1 to 5 hours;

3) Carbonization process: raise the temperature of the foam material matrix treated by the curing process in an oxygen-free environment, start the temperature at 150°C, increase the temperature by 2-10°C per minute, and carry out carbonization treatment at 600-1000°C for 30-120 minutes. Cool to room temperature in an oxygen-free environment;

4) Physical activation process: heat up the foam-carbon material treated by the carbonization process in an oxygen-free environment, start at 150°C, and increase the temperature by 2-10°C per minute. Carbon dioxide is the activation medium, the activation treatment is 30-120 minutes, and cooled to room temperature in an oxygen-free environment;

5) Chemical activation process: immerse the foam-carbon material treated by the carbonization process in a saturated solution of potassium hydroxide (KOH) or sodium hydroxide (NaOH) for 4 to 24 hours, and dry it in an oven at 120°C for 2 ~12 hours, then heat up in an oxygen-free environment, start at 150°C, increase the temperature by 2-10°C per minute, treat at 600-1000°C for 10-120 minutes, and cool to room temperature in an oxygen-free environment;

6) Cleaning process: the activated carbon-coated composite material treated by the activation process is pickled with hydrochloric acid (HCl) solution with a mass concentration of 5-20% for 4-12 hours, and then washed with water until neutral.

In the preparation method of the above-mentioned composite photocatalyst containing activated carbon coating, the foam material matrix adopts one of foam ceramics or foam metal.

In the preparation method of the above-mentioned composite photocatalyst containing activated carbon coating, the foam material matrix is foam ceramics, its porosity is 50-90%, and its main pore diameter is composed of randomly distributed three-dimensional channels with a diameter of 1mm-10mm.

In the above method for preparing a composite photocatalyst containing activated carbon coating, the thermosetting resin is one of phenolic resin, epoxy resin, unsaturated polyester, and acrylic resin.

The above-mentioned preparation method of a composite photocatalyst containing activated carbon coating, the thermosetting resin is a phenolic resin, including unmodified phenolic resin and modified phenolic resin, and the modified phenolic resin is melamine modified One or more mixtures of phenolic resin, aniline modified phenolic resin, epoxy modified phenolic resin, cashew nut shell oil or cardanol modified phenolic resin, polyvinyl alcohol modified phenolic resin, pitch modified phenolic resin .

The above-mentioned preparation method of a composite photocatalyst containing activated carbon coating, the solvent used in the thermosetting resin containing the solvent is one or a mixture of two or more of methanol, ethanol, butanol, toluene, xylene, gasoline .

In the above method for preparing a composite photocatalyst containing activated carbon coating, the oxygen-free environment is formed by mixing one or more of inert gas, CO ₂ or N ₂ .

Compared with the prior art, the present invention has the following advantages and effects due to the adoption of the above-mentioned technical scheme:

1. The high specific surface area and rich pore structure of activated carbon can improve the dispersion of TiO ₂ on the carrier, and have a good synergistic catalytic effect with TiO ₂ , which improves the catalytic efficiency of TiO ₂ and can greatly reduce the TiO 2 ₂ usage. In addition, the average particle diameter of the _TiO2 prepared by the present invention is in the range of nanoscale, the average particle diameter ranges from 10 to 50 nm, and the size distribution of the particle diameter is uniform.

2. The porosity of foamed ceramics is 50-90%, and its main pore diameter is composed of randomly distributed three-dimensional channels with a diameter of 1mm-10mm. The pore structure of the activated carbon in the pores and on the surface is composed of macropores, mesopores and micropores. , so that the mass transfer requirements of substances transferred to the surface of the catalyst can be fully met, and the function of activated carbon materials can be effectively played. The inherent three-dimensional network skeleton of foam ceramics, the interpenetrating pore structure, and the direction of the pores in the prepared activated carbon coating composite material are also three-dimensional random distribution, which can improve the light transmission and gas-liquid phase mass transfer in the photocatalytic oxidation process. Reduce the time of photocatalytic oxidation reaction and improve the efficiency of photocatalytic oxidation treatment.

3. The foam ceramic skeleton greatly improves the strength of activated carbon, avoids the disadvantages of wear and easy breakage of activated carbon as a carrier, and greatly prolongs the service life of activated carbon.

4. Activated carbon coating material can be made into various shapes according to needs, without size limitation.

Detailed ways

Embodiment 1 The preparation method that contains active carbon coating composite type photocatalyst comprises the steps:

1. Preparation of activated carbon coating material: ultrasonically clean a porous foam ceramic plate with a porosity of 75% for 20 minutes, dry it at 110°C for 4 hours, put it into a jacket with a solid content of 70 % liquid phenolic resin (solvent is ethanol) container, the porous foam ceramic plate was immersed in the immersion solution for 12 hours; the temperature of the circulating water in the jacket of the container for immersion was 35°C. Take out the porous foam ceramic plate impregnated with phenolic resin from the container, centrifuge at a speed of 1500r/min to remove excess resin, place it at room temperature for 12 hours, put it into an oven for curing treatment, and start the temperature at 70°C to The temperature was raised to 150°C at a heating rate of 3°C/min and kept for 2 hours. The cured ceramic-resin material was heated at 150°C in a nitrogen atmosphere, raised to 850°C at a rate of 8°C/min for carbonization treatment for 80 minutes, and cooled to room temperature in a nitrogen atmosphere. The carbonized ceramic-resin-carbon composite material was heated at 150°C in a nitrogen environment, raised to 900°C at a rate of 10°C/min, and activated by passing in supersaturated water vapor for 60 minutes. The total amount of water vapor was Twice the amount of resin-based carbon, cooled to room temperature in a nitrogen atmosphere. The obtained material was pickled with HCl solution with a mass concentration of 10%, washed with water until neutral, and dried to obtain a ceramic-activated carbon composite material with an activated carbon content of 7.46%, wherein the specific surface area of activated carbon was ^1350m2 /g, and the iodine adsorption value was 1682.19 mg/g.

2. Preparation of TiO ₂ sol: 150ml of absolute ethanol and 9.5ml of acetylacetone were added to a three-neck flask, and 75ml of tetrabutyl titanate was added dropwise under vigorous stirring. After dropping, continue to stir for 30 minutes to obtain a uniform and transparent light yellow solution, which is recorded as solution A; weigh polyethylene glycol with a weight content of 1.5% of the total weight of the TiO ₂ sol and dissolve it in 9.9ml of distilled water, and measure 1ml of HNO ₃ at the same time , 75ml of absolute ethanol and stir to make it evenly mixed, and record it as B solution; under vigorous stirring, use a burette to drop B solution into A solution at a speed of 0.2ml/s, adjust the pH value of the system to 2.5, continue to stir for 2h, and finally A uniform and transparent light yellow TiO ₂ sol was obtained, which was left to stand for 24 hours for later use.

3. TiO ₂ sol is loaded on the carrier: immerse the finished ceramic-activated carbon coating composite material that has been cleaned and dried in TiO ₂ sol for 2 hours, then slowly pull it out, put it in a closed container for gel aging for 24 hours, Then put it into a drying oven and dry it at 80°C for 2 hours; put the dried carrier in a box-type resistance furnace under a nitrogen environment, raise the temperature from room temperature to 250°C at a rate of 10°C/min, and keep it warm for 30 minutes; Then raise the temperature to 500°C at the same heating rate and keep it warm for 60 minutes; then cool to room temperature with the furnace. The above impregnation-calcination process was repeated twice to obtain a composite photocatalyst with a _TiO2 loading of 3.16%.

Using this catalyst to photocatalytically oxidize indoor formaldehyde gas, the formaldehyde removal rate can reach 94.3% under the conditions of reaction temperature 25°C, reaction time 120min, relative humidity 70%, and initial concentration of formaldehyde 2mg/m ³ .

Embodiment 2 The preparation method that contains active carbon coating composite type photocatalyst comprises the steps:

1. Preparation of ceramic-activated carbon coating composite material: Ultrasonic cleaning of a porous foam ceramic plate with a porosity of 55% for 20 minutes, drying at 110°C for 4 hours, and then putting it into a jacketed container filled with excess thermosetting phenolic resin In the process, the porous foam ceramic plate was immersed in the immersion solution for 12 hours; the temperature of the circulating water in the jacket of the immersion vessel was 45°C. Take out the porous foam ceramic plate impregnated with phenolic resin from the container, centrifuge at a speed of 1500r/min to remove excess resin, place it at room temperature for 12 hours, put it into an oven for curing treatment, start at 70°C, and heat at 4 The heating rate of °C/min was increased to 150 °C, and the temperature was kept for 2 hours. The cured ceramic-resin material was heated at 150°C in a nitrogen atmosphere, raised to 850°C at a rate of 10°C/min for carbonization treatment for 80 minutes, and cooled to room temperature in a nitrogen atmosphere. The ceramic-resin-carbon composite material after carbonization was started at 150°C in a nitrogen environment, raised to 900°C at a rate of 10°C/min, and activated by supersaturated water vapor for 60 minutes. The total amount of water vapor was Twice the amount of resin-based carbon, cooled to room temperature in a nitrogen atmosphere. The obtained material was pickled with HCl solution with a mass concentration of 10%, washed with water until neutral, and dried to obtain a ceramic-activated carbon composite material with an activated carbon content of 4.56%, wherein the specific surface area of activated carbon was ^1100m2 /g, and the iodine adsorption value was 1432.24 mg/g.

2. Preparation of TiO _sol : Add 30ml of absolute ethanol, 6ml of HNO ₃ and 9ml of acetylacetone into a three-necked flask, add 60ml of tetrabutyl titanate dropwise under vigorous stirring, and continue stirring for 30min to obtain a uniform and transparent pale Yellow solution, denoted as liquid A; weigh _polyethylene glycol (molecular weight: 20000) with a weight content of 1% of the total weight of TiO sol and dissolve it in 12ml distilled water, measure 60ml cyclopentane and add a certain amount of nonyl Phenolic polyoxyethylene ether emulsifier, mix the above two solutions and add isopropanol to it until a clear and transparent microemulsion is obtained, which is recorded as liquid B; under vigorous stirring, use a burette to dissolve liquid B at a speed of 0.2ml/s Add it dropwise into liquid A, adjust the pH value of the system to 1.5, continue to stir for 2 hours, and finally obtain a uniform and transparent light yellow TiO ₂ sol, and let it stand for 24 hours for later use.

3. TiO2 sol is loaded on the carrier: soak the finished ceramic-activated carbon coating composite material that has been cleaned and dried in TiO2 sol for 4 hours, then slowly pull it out, put it in a closed container for gel aging for 12 hours, and then put it Dry in a drying oven at 90°C for 2 hours; place the dried carrier in a box-type resistance furnace under nitrogen atmosphere, raise the temperature from room temperature to 250°C at a rate of 2°C/min, and keep it warm for 30 minutes; The temperature was raised to 550°C at the same heating rate, and kept for 60 minutes; then cooled to room temperature with the furnace. The above impregnation-calcination process was repeated twice to obtain a composite photocatalyst with a TiO2 loading of 3.52%.

Using this catalyst to photocatalytically oxidize indoor formaldehyde gas, the removal rate of formaldehyde can reach 88.7% under the conditions of reaction temperature 25°C, reaction time 120min, relative humidity 70%, and initial concentration of formaldehyde 1mg/m ³ .

Example 3 The preparation method of the composite photocatalyst containing activated carbon coating comprises the following steps:

1. The preparation method of the ceramic-activated carbon coating composite material: ultrasonically clean the porous foam ceramic tube with a porosity of 90% for 20 minutes, dry it at 110°C for 4 hours, put it into a jacket with an excess thermosetting In the container of phenolic resin, the porous foamed ceramic tube was immersed in the immersion solution for 16 hours; the temperature of the circulating water in the jacket of the immersion container was 35°C. Take out the porous foam ceramic tube impregnated with phenolic resin from the container, blow off excess resin with air, place it at room temperature for 10 hours, put it into an oven for curing treatment, start at 70°C, and heat up at a rate of 1°C/min The rate was raised to a temperature of 150°C, and the temperature was maintained for 2 hours. The cured ceramic-resin material was heated at 150°C in an argon atmosphere, raised to 800°C at a rate of 4°C/min for carbonization treatment for 60 minutes, and cooled to room temperature in an argon atmosphere. The impregnation-curing-carbonization process was repeated, and the ceramic-resin-based carbon composite material after two carbonization treatments was immersed in KOH saturated solution for 24 hours, dried in an oven at 120°C for 8 hours, and then dried in an argon environment. Start at 150°C, raise the temperature to 800°C at a rate of 10°C/min, perform activation treatment for 20 minutes, and cool to room temperature in an argon atmosphere. The obtained material was pickled with HCl solution with a mass concentration of 10%, washed with water until neutral, and dried to obtain a ceramic-activated carbon composite material with an activated carbon content of 14.5%, wherein the specific surface area of activated carbon was ^850m2 /g, and the iodine adsorption value was 909.36 mg/g.

2. The preparation of TiO ₂ sol and the loading of TiO ₂ sol on the carrier are the same as in Example 1.

Using this catalyst to photocatalytically oxidize indoor formaldehyde gas, the formaldehyde removal rate can reach 90.2% under the conditions of reaction temperature 30°C, reaction time 120min, relative humidity 50%, and initial concentration of formaldehyde 2mg/m ³ .

Embodiment 4 The preparation method that contains active carbon coating composite type photocatalyst comprises the steps:

1, the preparation method of ceramic-activated carbon coating composite material is the same as embodiment 3.

2. The preparation of TiO ₂ sol and the loading of TiO ₂ sol on the carrier are the same as in Example 2.

Using this catalyst to photocatalytically oxidize indoor formaldehyde gas, the formaldehyde removal rate can reach 85.5% under the conditions of reaction temperature 30°C, reaction time 120min, relative humidity 50%, and initial concentration of formaldehyde 1mg/m ³ .

Example 5 The preparation method of the composite photocatalyst containing activated carbon coating comprises the following steps:

1, the preparation method of ceramic-activated carbon coating composite material is the same as embodiment 3.

2. Preparation of _TiO2 sol: Add 100ml of absolute ethanol and 12ml of acetylacetone into a three-necked flask, add 75ml of tetrabutyl titanate dropwise under vigorous stirring, and continue stirring for 30 minutes to obtain a uniform and transparent light yellow solution. It is liquid A; weigh the polyethylene glycol (molecular weight: 20000) whose weight content accounts for 2% of the total weight of the _TiO2 sol, dissolve it in 12ml distilled water, measure 2ml HCl, 75ml absolute ethanol and stir to make it mix evenly at the same time, record as Liquid B: under vigorous stirring, use a burette to add liquid B dropwise to liquid A at a speed of 0.2ml/s, adjust the pH value of the system to 2.5, continue stirring for 2 hours, and finally obtain a uniform and transparent light yellow TiO ₂ sol, and let it stand for 24 hours spare.

3. TiO ₂ sol is loaded on the carrier: soak the finished ceramic-activated carbon coating composite material that has been cleaned and dried in TiO ₂ sol for 2 hours, then slowly pull it out, put it in a closed container for gel aging for 12 hours, Then put it into a drying oven and dry it at 80°C for 4 hours; put the dried carrier in a box-type resistance furnace under nitrogen atmosphere, raise the temperature from room temperature to 250°C at a heating rate of 2°C/min, and keep it for 30 minutes; Then raise the temperature to 550°C at the same heating rate and keep it warm for 120 minutes; then cool to room temperature with the furnace. The above impregnation-calcination process was repeated twice to obtain a composite photocatalyst with a _TiO2 loading of 4.31%.

Using this catalyst to photocatalytically oxidize indoor formaldehyde gas, the formaldehyde removal rate can reach 84.7% under the conditions of reaction temperature 25°C, reaction time 120min, relative humidity 70%, and initial concentration of formaldehyde 2mg/m ³ .

Claims (10)

1. A preparation method containing activated carbon coating compound type photocatalyst, it is characterized in that, the method is that activated carbon is attached on the foam material matrix as coating, forms activated carbon coating material, and takes this activated carbon coating material as carrier Titanium dioxide is loaded, wherein the weight percentage of each component is: the active component of titanium dioxide is 1-10%, the active carbon coating is 4-15%, and the rest is a foam material matrix. 2. a kind of preparation method that contains activated carbon coating composite type photocatalyst as claimed in claim 1, is characterized in that, when using described activated carbon coating material as carrier loading titanium dioxide, adopt impregnation method to carry titanium dioxide sol on the The activated carbon coating material carrier is obtained through high-temperature calcination, and the preparation steps are as follows: 1) Dissolve titanium alkoxide in alcohol under vigorous stirring, add a certain amount of inhibitor and surfactant, slowly add a mixture of water, alcohol and acid, and continue stirring; titanium alkoxide and inhibitor, alcohol, water The volume ratio of the surfactant is 6-8: 1: 16-25: 0.75-1.5, the addition amount of the surfactant is 1-3% of the total weight of the titanium dioxide sol, stirring and mixing to obtain a uniform, stable and transparent titanium dioxide sol; 2) Immerse the active carbon coating material carrier in the titanium dioxide sol for 2-4 hours, take it out and place it in a closed container for gel aging for 12-24 hours, then put it in a drying oven and dry it at a temperature of 80-110°C for 2-2 hours. 4h; place the dried carrier in a resistance furnace in an oxygen-free environment from room temperature to 450-650°C, keep it warm for 40-90min; then cool down to room temperature with the furnace. 3. a kind of preparation method containing activated carbon coating composite photocatalyst as claimed in claim 2, is characterized in that, described titanium alkoxide is tetrabutyl titanate; Described alcohol is ethanol, Virahol, normal One or a mixture of two or more butanols; the acid is one or a mixture of two or more of nitric acid, sulfuric acid, and hydrochloric acid; the inhibitor is one of acetylacetone, glacial acetic acid, and diethanolamine ; The surfactant is one or a mixture of two or more of polyethylene glycol, polyvinyl alcohol, and nonylphenol polyoxyethylene ether. 4. a kind of preparation method that contains activated carbon coating composite photocatalyst as claimed in claim 1, is characterized in that, the described activated carbon coating that is attached on foam material is prepared by thermosetting resin, adopts impregnation process to contain solvent The thermosetting resin is coated on the inner and outer surfaces of the foam material, and the thermosetting resin is treated as a carbon precursor through a curing process, a carbonization process, an activation process and a cleaning process to obtain an activated carbon coating attached to the foam ceramics, and the activated carbon coating It is 5-20% of the total mass of the activated carbon coating material, the coating thickness is 0.1-1mm, and the surface area of the activated carbon coating is 800-1400m ² /g. The preparation process is as follows: 1) Impregnation process: after ultrasonic cleaning, the foam material matrix is dried at 105±5°C for 4 to 8 hours, placed in a jacketed container filled with thermosetting resin, and immersed in the impregnation solution for 4 to 16 hours. Hours, there is warm water circulation in the jacket of the container used for impregnation, and the temperature of the warm water is 20-70°C; the foam material matrix impregnated with thermosetting resin is taken out from the container, and the excess thermosetting resin is removed by air blowing or centrifuge; 2) Curing process: put the foam material matrix impregnated with thermosetting resin at room temperature for 6-12 hours, then put it into an oven for curing, start at 70°C, increase the temperature by 1-4°C per minute, and keep it warm at 150°C 1 to 5 hours; 3) Carbonization process: raise the temperature of the foam material matrix treated by the curing process in an oxygen-free environment, start the temperature at 150°C, increase the temperature by 2-10°C per minute, and carry out carbonization treatment at 600-1000°C for 30-120 minutes. Cool to room temperature in an oxygen-free environment; 4) Physical activation process: heat up the foam-carbon material treated by the carbonization process in an oxygen-free environment, start at 150°C, and increase the temperature by 2-10°C per minute. Carbon dioxide is the activation medium, the activation treatment is 30-120 minutes, and cooled to room temperature in an oxygen-free environment; 5) Chemical activation process: immerse the foam-carbon material treated by the carbonization process in a saturated solution of potassium hydroxide or sodium hydroxide for 4 to 24 hours, dry it in an oven at 120°C for 2 to 12 hours, and then Heating in an anaerobic environment, starting at 150°C, increasing the temperature by 2-10°C per minute, processing at a temperature of 600-1000°C for 10-120 minutes, and cooling to room temperature in an oxygen-free environment; 6) Cleaning process: the activated carbon-coated composite material treated by the activation process is pickled with hydrochloric acid solution with a mass concentration of 5-20% for 4-12 hours, and then washed with water until neutral. 5. the preparation method of a kind of active carbon coating composite photocatalyst as claimed in claim 1, is characterized in that, described foam material substrate adopts a kind of in foam ceramics or foam metal. 6. a kind of preparation method that contains activated carbon coating composite type photocatalyst as claimed in claim 5, is characterized in that, described foam material matrix is ceramic foam, and its porosity is 50～90%, and its main aperture is by diameter It is composed of three-dimensional channels randomly distributed from 1mm to 10mm. 7. a kind of preparation method that contains activated carbon coating composite photocatalyst as claimed in claim 4, is characterized in that, described thermosetting resin is a kind of of phenolic resin, epoxy resin, unsaturated polyester, acrylic resin . 8. a kind of preparation method that contains activated carbon coating composite photocatalyst as claimed in claim 7, is characterized in that, described thermosetting resin is phenolic resin, comprises unmodified phenolic resin and modified phenolic resin, so Described modified phenolic resin is melamine modified phenolic resin, aniline modified phenolic resin, epoxy modified phenolic resin, cashew nut shell oil or cardanol modified phenolic resin, polyvinyl alcohol modified phenolic resin, asphalt modified One or more mixtures of phenolic resins. 9. a kind of preparation method that contains activated carbon coating composite type photocatalyst as claimed in claim 4, is characterized in that, used solvent is methyl alcohol, ethanol, butanol, toluene, dimethylbenzene in the described thermosetting resin that contains solvent , gasoline or a mixture of two or more. 10. a kind of preparation method that contains active carbon coating composite type photocatalyst as claimed in claim 2, is characterized in that, described anaerobic environment is by inert gas, CO _in or N _In one or more mixing after composition.