CN104307473B - A kind of preparation method of the absorption visible light catalytic material for air pollution treatment - Google Patents

Abstract

The invention relates to a method for preparing an adsorption visible light catalytic composite functional material for air treatment. Specifically, coal gangue, asphalt powder and tourmaline are used as raw materials to prepare activated carbon-zeolite composites with permanent negative charges. As WO ₃ /TiO ₂ Catalyst Support Synthesis of Adsorption-Visible Light Catalytic Materials. In this composite material, tourmaline naturally has a permanent negative charge, which can continuously and efficiently absorb positively charged PM2.5 in the air. The activated carbon-zeolite composite produced by coal gangue has a large specific surface area and has the hydrophilicity of zeolite. And the hydrophobic characteristics of activated carbon, it has good specific adsorption for polar pollutants and hydrophobic VOCs in the air. Under sunlight, the above-mentioned adsorbed pollutants can be degraded and removed by WO ₃ /TiO ₂ catalyst. The product of the invention can be used in the technical field of exterior wall coatings, and can maintain self-cleaning after being washed by rainwater, so as to realize continuous and efficient purification of polluted air.

Description

A preparation method of adsorption visible light catalytic material for air pollution control

technical field

The invention belongs to the technical field of air pollution control, and in particular relates to a preparation method of an adsorption-visible light catalysis composite functional material used for air control.

Background technique

With the rapid development of my country's economy, the acceleration of urbanization and the expansion of industrial scale, regional air pollution is becoming more and more serious. In recent years, smog weather characterized by fine particulate matter has appeared successively in many regions of my country, posing a huge threat to visibility, public health and urban landscape.

Among the existing air pollution control technologies, photocatalytic materials have become one of the effective ways to solve urban air pollution because of their remarkable air purification efficiency. The principle of photocatalytic technology is to use photocatalytic materials to convert solar energy into chemical energy, oxidize and degrade toxic and harmful substances, and achieve harmless treatment. The photocatalytic reaction has a generally good degradation effect on volatile organic compounds (VOCs) in the air. At the same time, it can also oxidize and remove inorganic pollutants (NOx, CO, H ₂ S, etc.) Bacteria and viruses in the air also have a good killing effect. Among many photocatalytic/sensitizing semiconductor materials, titanium dioxide (TiO ₂ ) has attracted widespread attention due to its cleanliness, safety, and environmental friendliness.

In recent years, some achievements have been made in the research and industrial application of photocatalytic environmental purification coatings at home and abroad. For example, the patent CN101629031B discloses a preparation method of a photocatalytic functional coating capable of sterilizing and decomposing toxic substances, which can be used in technical fields such as interior wall coatings and textile fabrics. Patent CN102776993A discloses a photocatalyst building outer wall with anti-fouling and self-cleaning functions. By spraying _TiO2 photocatalyst on the substrate surface of the building, the outer wall has anti-fouling and self-cleaning functions. Practice has shown that coating photocatalyst materials on the surface of urban roads and building facades can effectively degrade pollutants such as _NOx , VOCs and sulfur oxides in the air through the catalytic degradation function of light, thereby indirectly eliminating PM2.5 , It has a good effect on purifying urban air pollutants and improving air quality, and at the same time does not affect the use function of the building, nor does it affect the appearance of the building.

Although the application of nano-TiO ₂ in environmental purification coatings has achieved remarkable and fruitful results, there are still some problems that are not conducive to practical promotion. (1) The use of nano-TiO ₂ has certain dependence and limitations on the environment, and its utilization rate of ultraviolet light source is extremely high, while the utilization of common visible light source (such as: sunlight) is insufficient, and the efficiency is very low, but in In sunlight, the proportion of ultraviolet light source is less than 6%, which greatly limits the scope of application of nano- _TiO2 environmental purification coatings. (2) In the gas phase reaction system, the pre-adsorption of pollutants on the surface of the catalyst is very important to improve the photocatalytic oxidation rate, while the existing TiO ₂ composite photocatalytic materials often only focus on the self-cleaning function, which is harmful to VOCs and PM2. The adsorption performance of pollutants such as 5 is poor, which directly affects its actual air purification effect.

Contents of the invention

The invention aims to overcome the disadvantages of the prior art, and provides a method for preparing an adsorbed visible light catalytic composite functional material for air treatment. Specifically, coal gangue, asphalt powder and tourmaline are used as raw materials to prepare high-quality activated carbon-zeolite composites, which are used as carriers to support WO ₃ /TiO ₂ to synthesize adsorption-visible light catalysts for PM2.5 and VOCs in the air. Efficient adsorption-photocatalytic removal of pollutants such as

The present invention proposes a method for preparing an adsorbed visible light catalytic material for air pollution control, wherein the adsorbed visible light catalytic material is an activated carbon _- zeolite material loaded with WO3/ _TiO2 , and the specific steps are as follows:

(1) Mix coal gangue, tourmaline and asphalt powder with a particle size below 200 meshes according to the weight ratio of coal gangue: tourmaline: asphalt powder (0.5~0.9): (0.05~0.15): (0.1~0.3) , and fully mixed to obtain material A;

(2) At room temperature, mix tetra-n-butyl titanate and absolute ethanol at a volume ratio of 1:1, and stir for 0.5~2 hours to obtain a uniform and transparent yellow solution B;

(3) Mix the material A obtained in step (1) and the yellow solution B obtained in step (2) according to the mass volume ratio of 1:1~5, age for 24~48h, in the carbon dioxide gas with a flow rate of 200mL/min Under the same conditions, the temperature was raised to 500~800°C for 6~12 hours of carbonization, and after cooling to room temperature, material C was obtained;

(4) Mix the material C obtained in step (3) and sodium tungstate aqueous solution according to the mass volume ratio (w/v) of 10%, ultrasonically oscillate for 4~8h, then wash and dry, and activate at 400~550°C in a nitrogen atmosphere for 2 ~4h, after cooling to room temperature, crush to below 150 mesh to obtain the finished product.

In the present invention, the weight ratio of the material C to sodium tungstate is (0.8~0.95): (0.05~0.2).

Principle: Coal gangue, asphalt powder and tourmaline are used as raw materials to prepare activated carbon-zeolite composites with permanent negative charges, which are used as the carrier of WO ₃ /TiO ₂ catalysts to synthesize adsorption visible light catalytic composite materials. In this composite material, tourmaline naturally has a permanent negative charge, which can continuously and efficiently absorb positively charged PM2.5 in the air. The activated carbon-zeolite composite produced by coal gangue has a large specific surface area and has the hydrophilicity of zeolite. And the hydrophobic characteristics of activated carbon, it has good specific adsorption for polar pollutants and hydrophobic VOCs in the air. Under sunlight, the above-mentioned adsorbed pollutants can be degraded and removed by WO ₃ /TiO ₂ catalyst. The product of the invention can be used in the technical field of exterior wall coatings, and can maintain self-cleaning after being washed by rainwater, so as to realize continuous and efficient purification of polluted air.

Compared with the prior art, the present invention has the following advantages:

1. In the preparation of adsorbed photocatalytic materials, the addition of asphalt powder can not only serve as a binder to improve the mechanical strength of the composite material, but also play a role in carbon supplementation, thereby adjusting the ratio of activated carbon/zeolite in the composite material. The prepared composite material has both the hydrophilicity of zeolite and the hydrophobicity of activated carbon, and has a large specific surface area and microporous adsorption channels, which can achieve efficient adsorption of pollutants in the air.

2. Adding tourmaline to the adsorption photocatalytic material, the natural permanent negative charge on its surface matches the positive charge of PM2.5, making it have the unique function of adsorbing PM2.5.

3. WO ₃ /TiO ₂ photocatalyst has good visible light catalytic performance, can make full use of sunlight energy, and realize the complete degradation and removal of adsorbed air pollutants.

4. The adsorption photocatalytic material uses cheap coal gangue as the main raw material, which is low in cost and economically feasible, and realizes self-purification through the action of rainwater in application without additional maintenance.

detailed description

The following examples will further illustrate the present invention.

Example 1

(1) Proportion coal gangue, tourmaline and asphalt powder with a particle size of 200 meshes according to the weight ratio of coal gangue: tourmaline: asphalt powder = 0.8:0.05:0.15, and fully mix them to obtain material A.

(2) At room temperature, mix tetra-n-butyl titanate and absolute ethanol at a volume ratio of 1:1, and stir for 0.5 h to obtain a uniform and transparent yellow solution B.

(3) Mix the material A and the yellow solution B at a mass volume ratio of 1:3, age for 24 hours, heat up to 650°C for carbonization for 6 hours under the condition of carbon dioxide gas with a flow rate of 200mL/min, and cool to room temperature to prepare Get material C.

(4) Mix material C and sodium tungstate aqueous solution according to the mass volume ratio (w/v) of 10% (the weight ratio of material C and sodium tungstate is 0.95:0.05), ultrasonically oscillate for 4 hours, then wash and dry, nitrogen atmosphere Activation at 400°C for 2 hours, cooling to room temperature and crushing to below 150 mesh to obtain the finished product.

The "GBT23761-2009 Photocatalytic Air Purification Material Performance Test Method" was used to test the air purification ability of the prepared material. In the experiment, 0.5g of the above-mentioned adsorbed visible light catalytic material prepared above was coated on a 200mm×100mm flake glass. The initial concentration of toluene was At 6mg/L, visible light irradiation for 8 hours, the removal rate reached 96%, and the treatment effect was good.

Example 2

(1) Proportion coal gangue, tourmaline and asphalt powder with a particle size of 200 meshes according to the weight ratio of gangue: tourmaline: asphalt powder = 0.85:0.03:0.12, and fully mix them to obtain material A.

(2) At room temperature, mix tetra-n-butyl titanate and absolute ethanol at a volume ratio of 1:1, and stir for 0.5 h to obtain a uniform and transparent yellow solution B.

(3) Mix material A and yellow solution B at a mass volume ratio of 1:3, age for 12 hours, raise the temperature to 550°C for carbonization for 6 hours under the condition of carbon dioxide gas with a flow rate of 200mL/min, and cool to room temperature to prepare Get material C.

(4) Fully mix material C and sodium tungstate aqueous solution according to the mass volume ratio (w/v) of 10% (the weight ratio of material C and sodium tungstate is 0.93:0.07), ultrasonically oscillate for 4 hours, then wash and dry, nitrogen atmosphere Activation at 500°C for 2 hours, cooling to room temperature and crushing to below 150 mesh to obtain the finished product.

The "GBT23761-2009 Photocatalytic Air Purification Material Performance Test Method" was used to test the air purification ability of the prepared material. In the experiment, 0.5g of the above-mentioned adsorbed visible light catalytic material was coated on a 200mm×100mm flake glass. The initial concentration of formaldehyde was When the concentration is 10mg/L, visible light is irradiated for 11 hours, and the removal rate reaches 94%, and the treatment effect is good.

Example 3

(1) Proportion coal gangue, tourmaline and asphalt powder with a particle size of 200 meshes according to the weight ratio of coal gangue: tourmaline: asphalt powder = 0.7:0.08:0.22, and fully mix them to obtain material A.

(2) At room temperature, mix tetra-n-butyl titanate and absolute ethanol at a volume ratio of 1:1, and stir for 0.5 h to obtain a uniform and transparent yellow solution B.

(3) Mix the material A and the yellow solution B at a mass volume ratio of 1:4, age for 24 hours, heat up to 600°C for carbonization for 8 hours under the condition of carbon dioxide gas with a flow rate of 200mL/min, and cool to room temperature to prepare Get material C.

(4) Fully mix material C and sodium tungstate aqueous solution according to the mass volume ratio (w/v) of 10% (the weight ratio of material C and sodium tungstate is 0.95:0.05), ultrasonically oscillate for 4 hours, then wash and dry, nitrogen atmosphere Activation at 500°C for 2 hours, cooling to room temperature and crushing to below 150 mesh to obtain the finished product.

Use the PM2.5 experimental cabin and PM2.5 detector to test the adsorption and photocatalytic removal performance of the product to be tested on PM2.5. In the experiment, 0.5g of the adsorption visible light catalytic material prepared above is coated on a 200mm×100mm flake glass. , when the PM2.5 concentration is 73ug/m ³ and the adsorption time is 30min, the adsorption rate of the product to PM2.5 is over 54%. Under the condition of visible light, the organic pollution in PM2.5 can be completely degraded and removed.

Claims (1)

1. A method for preparing an adsorption-visible light catalytic material for air pollution control, characterized in that said adsorption visible light catalytic material is loaded with WO ₃ /TiO ₂ activated carbon-zeolite material, the specific steps are as follows: (1) Mix coal gangue, tourmaline and asphalt powder with a particle size below 200 meshes according to the weight ratio of coal gangue: tourmaline: asphalt powder (0.5~0.9): (0.05~0.15): (0.1~0.3) , and fully mixed to obtain material A; (2) At room temperature, mix tetra-n-butyl titanate and absolute ethanol at a volume ratio of 1:1, and stir for 0.5~2 hours to obtain a uniform and transparent yellow solution B; (3) Mix the material A obtained in step (1) and the yellow solution B obtained in step (2) according to the mass volume ratio of 1:1~5, age for 24~48h, in the carbon dioxide gas with a flow rate of 200mL/min Under the same conditions, the temperature was raised to 500~800°C for 6~12 hours of carbonization, and after cooling to room temperature, material C was obtained; (4) Mix the material C obtained in step (3) and sodium tungstate aqueous solution according to the mass volume ratio (w/v) of 10%, ultrasonically oscillate for 4~8h, then wash and dry, and activate at 400~550°C in a nitrogen atmosphere for 2 ~4h, after cooling at room temperature, pulverize to below 150 mesh to obtain the finished product; the weight ratio of the material C to sodium tungstate is (0.8~0.95): (0.05~0.2).