CN106179396A - A kind of composite catalyst of ozone decomposition and preparation method thereof - Google Patents

Abstract

A method for preparing a composite catalyst for decomposing ozone, said method comprising the following steps: respectively dissolving permanganate, Mn ^II salt and Cu ^II salt to obtain three kinds of salt solutions; rapidly mixing and stirring the three kinds of salt solutions Carry out oxidation-reduction reaction, then filter and wash to obtain the filter residue of composite oxide; add the filter residue to water and mix to form a suspension of filter residue and water, carry out ultrafine grinding treatment on the suspension, and fully grind the obtained After the suspension is subjected to a freeze-drying process, the composite catalyst for decomposing ozone is obtained. The method of the invention has few synthesis steps, simple synthesis conditions, simple ultrafine grinding process, good dispersion effect, sufficient mixing and doping of various substances in the prepared composite catalyst, and significantly improved catalytic effect.

Description

A composite catalyst for decomposing ozone and its preparation method

technical field

The invention relates to a preparation method of an environmental protection and air purification material, in particular to a composite catalyst for catalyzing ozone decomposition and a preparation method thereof.

Background technique

Ozone (O ₃ ) is a light blue gas with a special odor. It mainly exists in the ozone layer 20-35 kilometers away from the earth's surface, and resists the direct irradiation of ultraviolet rays on the earth. Normally, inhalation of a small amount is beneficial to the human body, but excessive inhalation is harmful to human health. The national standard stipulates that the concentration of ozone in indoor air should not exceed 0.08mg/m ³ , and the maximum allowable concentration of ozone is 0.16mg/m ³ . Once this concentration is exceeded, it will cause harm to the human body. Excessively high concentrations of ozone can irritate the respiratory tract, causing damage to the throat, trachea, and lungs. In severe cases, it can cause vision loss, fetal malformation, and neurotoxicity.

Due to its strong oxidizing properties, ozone is usually used for disinfection in industries such as food, medical and sanitation, and water treatment. However, it is difficult to completely remove it after use and is directly discharged into our working and living areas; in addition, ozone from other equipment such as copiers and high-voltage discharges in nature inevitably enters the atmosphere. In addition, with the rapid popularization of air purification products, the application of electrostatic precipitator products is becoming more and more extensive. However, in the process of working with high-voltage electrostatic precipitator modules, the higher the voltage, the more ozone will be generated. If it is not treated, Excessive ozone will inevitably enter the air. Excessive ozone entering the air will not only produce unpleasant odors and affect the environment, but also seriously damage human health. The application of electrostatic precipitator air purifiers is also limited due to the difficulty in handling the generated ozone.

At present, there are many methods for removing ozone pollution, among which the representative ones are liquid absorption method, solid adsorption method, photocatalysis method and room temperature catalysis method. Among them, the liquid medicine adsorption method adopts liquid absorption, which is difficult to be widely applied to the removal of ozone in the air; the solid adsorption method usually uses inorganic porous materials for physical adsorption to achieve the purpose of ozone removal, but the adsorption capacity of the material is limited. After reaching saturation, it cannot be used continuously and there is a risk of releasing secondary pollutants, and it is not the best solution to the problem of ozone pollution; photocatalysis usually uses materials that can catalyze the decomposition of ozone, because it requires photocatalytic conditions, It is difficult to apply in indoor and other environments; the normal temperature catalytic method mainly uses catalysts to catalyze the decomposition of ozone at room temperature without any additional conditions to achieve the purpose of removal, and it is a long-term effective and practical method.

CN 103127942 A discloses an ozone decomposition catalyst and its preparation method. The iron-copper composite oxide is used as the main active component and gold is the co-active component. The iron-copper-gold composite catalyst is prepared by precipitation method. The catalyst has high catalytic activity and stability for the decomposition of ozone in indoor air. However, due to the high price of precious metals, it is difficult to be widely used. CN 102513106 B discloses a normal-temperature high-efficiency ozone decomposition catalyst and its preparation method, wherein a precipitation method is adopted, potassium carbonate and/or potassium bicarbonate are used as a precipitating agent, and potassium chlorate is used as an oxidant to precipitate to form an active component, and then Add N,N-diethylethylamine, crystallize in the reaction kettle at 180°C-220°C, and make it through high-temperature roasting process. The preparation process is complicated, and many dangerous reagents are used, which is not conducive to realizing safe production, so it is difficult to implement industrial production; and it is easy to cause agglomeration in the final high-temperature roasting process, which reduces the catalytic activity of the catalyst.

Contents of the invention

In view of the problems involved above, the object of the present invention is to provide a method for preparing a composite catalyst for catalytic ozonolysis, which is safe and simple, has high dispersibility, and can efficiently catalyze and decompose ozone. The material is a composite catalyst material of manganese dioxide and copper oxide, and various composite components have realized the composite at the lattice level, which has high catalytic activity; the composite catalyst has high dispersion and small enough particle size for The catalytic reaction of ozone provides enough space.

In order to achieve the above object, the present invention is a synthesis method of a composite catalyst that catalyzes the decomposition of ozone by adopting the following technical scheme, using manganese and copper for effective compounding to obtain copper-doped composite oxides, first obtained by oxidation-reduction method in solution The manganese dioxide and copper oxide composite material is processed through an ultra-fine grinding process to obtain a composite catalyst material with a high degree of dispersion.

The preparation process of the composite catalyst material for decomposing ozone mainly includes the preparation process of metal salt solution and oxide, the redox reaction in the solution and the ultrafine grinding dispersion process, specifically as follows: the catalytic ozone decomposition composite catalyst material of the present invention, which It is prepared by the following method: dissolving permanganate, Mn ^II salt and Cu ^II salt respectively to obtain a salt solution; these three solutions are quickly mixed and stirred for redox reaction to obtain a composite oxide precipitate, and then filtered and washed to obtain Filter residue; finally, add the filter residue to water and mix to form a suspension of filter residue and water, carry out ultrafine grinding on the suspension, fully grind the suspension and then go through the freeze-drying process to obtain molecular level mixing highly dispersed composite oxide catalysts.

As preferably, described permanganate can select potassium permanganate for use;

As a preference, the Mn ^II salt can be selected from any one or more of manganese sulfate, manganese nitrate, manganese carbonate, and manganese chloride;

As a preference, the Cu ^II salt can be selected from one or more of copper sulfate, copper nitrate and copper chloride.

As a preference, the preparation concentration of the permanganate solution is 10-30wt%, preferably 10-25wt%;

As a preference, the preparation concentration of the Mn ^II salt solution is 5-30wt%, preferably 10-20wt%;

As a preference, the preparation concentration of the Cu ^II salt solution is 3-30wt%, preferably 8-20wt%;

As a preference, the molar ratio of the Mn ^II salt, permanganate and Cu ^II salt is 1: (2.1-4): (0.05-1), wherein the preferred ratio is 1: (2.2-3.5) : (0.2-1).

As a preference, the temperature range of the redox reaction is -10-99°C, preferably 10-90°C;

As a preference, the time range of the redox reaction is 0.5-30h, preferably 0.5-20h;

As a preference, the particle size of the ball in the ultrafine grinding process is 0.2-0.5mm, and the rotation speed is 1000-2100r/min:

As a preference, the solid content in the suspension is 5wt%-50wt%;

Preferably, the sufficient time is 30-600min, preferably 60-480min;

As preferably, the freeze-drying temperature of the suspension does not exceed room temperature;

As preferably, the freeze-drying time of the suspension is 5-48h;

Compared with the prior art, it has the following advantages:

1. The synthesis steps of composite catalyst materials are few, and each raw material undergoes co-precipitation through oxidation-reduction reaction, realizing the composite at the molecular level;

2. The synthesis conditions of composite catalyst materials are simple;

3. The superfine grinding process is simple and the dispersion effect is good;

4. Various substances in the composite catalyst are fully mixed and doped, which significantly improves the catalytic effect.

Description of drawings

Figure 1 is a flow chart of the composite catalyst synthesis process for decomposing ozone.

Figure 2 is a transmission electron microscope image of the composite catalyst for decomposing ozone.

detailed description

Example 1

Fully dissolve 19.8g manganese chloride tetrahydrate in 100mL pure water, fully dissolve 34.76g potassium permanganate in 200mL pure water, then dissolve 0.25g copper sulfate pentahydrate in 50mL pure water, and mix the above three solutions Fully dissolved for use. The above-mentioned three solutions were quickly mixed and stirred, and the above-mentioned mixed solution was stirred and reacted at room temperature for 10 h, and then cleaned by suction filtration to obtain a composite oxide filter residue. Add the filter residue obtained above to the ultrafine grinding equipment, add 19g of water to obtain a suspension with a solid content of 50%, select 0.2mm zirconia balls, and set the speed of the ultrafine mill to 2100r/min for grinding for 10h. The ground suspension was freeze-dried at -50°C for 20 hours to obtain a highly dispersed composite catalyst powder.

Through SEM test (see Fig. 2), show that the composite catalyst of decomposing ozone synthesized is nanoscale material, and its particle size is in the scope of 20-80nm.

Take 1.00 g of the dispersed catalytic ozonolysis composite catalyst material prepared above and place it on a sand core in a glass tube with a diameter of 2 mm to evaluate its catalytic decomposition performance. The bottom of the glass tube is connected to the air pump (connected to the gas outlet of the ozone generator), and the top is connected to the online detector of the ultraviolet spectrophotometer. When the air with an ozone content of 100ppm is generated in the ozone generator, it is discharged from the air outlet, and the ozone-containing air is added at a rate of 800mL/min, and then transported by the air pump to the glass tube to react with the composite catalytic material, and finally from the top of the glass tube It overflows into the ultraviolet spectrophotometer connected with it, and the ozone content in the tail gas is measured by the detector. The test results show that the highly dispersed composite catalyst prepared in this example has a catalytic decomposition efficiency of 90% for 100 ppm ozone at room temperature.

Example 2

Fully dissolve 7.8g manganese sulfate tetrahydrate in 100mL pure water, fully dissolve 22.1g potassium permanganate in 100mL pure water, then dissolve 6.03g copper chloride dihydrate in 95mL pure water, and mix the above three solutions Fully dissolved for use. The above three solutions were quickly mixed and stirred, and the above mixed solution was stirred and reacted at 0° C. for 30 h, and then filtered and washed to obtain a composite oxide filter residue. Add the filter residue obtained above to the ultrafine milling equipment, add 36.4g of water to obtain a suspension with a solid content of 30%, select 0.3mm alumina balls, and set the speed of the ultrafine mill to 1500r/min for grinding for 6h. The ground suspension was freeze-dried at -20°C for 15 hours to obtain a composite catalyst powder for decomposing ozone.

The catalytic performance test is the same as in Example 1. The test results show that the highly dispersed composite catalyst prepared in this example has a catalytic decomposition efficiency of 92% for 100 ppm of ozone at room temperature.

Example 3

Fully dissolve 14.35g manganese nitrate hexahydrate in 130mL pure water, fully dissolve 22.1g potassium permanganate in 200mL pure water, fully dissolve 8.45g copper nitrate trihydrate in 85mL pure water, and fully dissolve the above three solutions Dissolve and set aside. The above three solutions were quickly mixed and stirred, and the above mixed solution was stirred and reacted at 40° C. for 5 hours, and then filtered and washed to obtain a composite oxide filter residue. Add the filter residue obtained above to the ultrafine grinding equipment, add 187.4g of water to obtain a suspension with a solid content of 10%, select 0.4mm alumina balls, and set the speed of the ultrafine mill to 1800r/min for grinding for 1h. The ground suspension was freeze-dried at 0° C. for 30 h to obtain a composite catalyst powder for decomposing ozone.

The catalytic performance test is the same as in Example 1, and the test results show that the highly dispersed composite catalyst prepared in this example has a catalytic decomposition efficiency of 93% for 100 ppm of ozone at room temperature.

Example 4

Fully dissolve 15g manganese sulfate tetrahydrate in 150mL pure water, fully dissolve 26.9g potassium permanganate in 200mL pure water, fully dissolve 5g copper sulfate pentahydrate in 50mL pure water, fully dissolve the above three solutions and wait for use. The above-mentioned three solutions were quickly mixed and stirred, and the above-mentioned mixed solution was stirred and reacted at 30° C. for 20 h, and then cleaned by suction filtration to obtain a composite oxide filter residue. Add the filter residue obtained above to the ultrafine grinding equipment, add 407g of water to obtain a suspension with a solid content of 5%, select 0.5mm zirconia balls, and set the speed of the ultrafine mill to 1200r/min for grinding for 1h. The ground suspension was freeze-dried at 2° C. for 5 hours to obtain a composite catalyst powder for decomposing ozone.

The catalytic performance test is the same as in Example 1. The test results show that the highly dispersed composite catalyst prepared in this example has a catalytic decomposition efficiency of 91% for 100 ppm of ozone at room temperature.

Example 5

Fully dissolve 14.35g manganese sulfate tetrahydrate in 150mL pure water, fully dissolve 23.7g potassium permanganate in 200mL pure water, fully dissolve 7.5g copper sulfate pentahydrate in 50mL pure water, and fully dissolve the above three solutions Dissolve and set aside. The above three solutions were quickly mixed and stirred, and the above mixed solution was stirred and reacted at 50° C. for 2 hours, and then filtered and washed to obtain a composite oxide filter residue. Add the filter residue obtained above to the ultrafine grinding equipment, add 69g of water to obtain a suspension with a solid content of 25%, select 0.2mm zirconia balls, and set the speed of the ultrafine mill to 1500r/min for grinding for 2h. The ground suspension was freeze-dried at 5° C. for 8 hours to obtain a composite catalyst powder for decomposing ozone.

The catalytic performance test is the same as in Example 1. The test results show that the highly dispersed composite catalyst prepared in this example has a catalytic decomposition efficiency of 94% for 100 ppm of ozone at room temperature.

Comparative example 1

Fully dissolve 19.8g manganese chloride tetrahydrate in 100mL pure water, fully dissolve 34.76g potassium permanganate in 200mL pure water, then dissolve 0.25g copper sulfate pentahydrate in 50mL pure water, and mix the above three solutions Fully dissolved for use. The above-mentioned three solutions were quickly mixed and stirred, and the above-mentioned mixed solution was stirred and reacted at room temperature for 10 h, and then cleaned by suction filtration to obtain a composite oxide filter residue. Add the filter residue obtained above to ordinary ball milling equipment, add 19g of water to obtain a suspension with a solid content of 50%, select 0.2mm zirconia balls, and use ordinary ball milling for 10 hours. The ground suspension was freeze-dried at -50°C for 20 hours to obtain catalytic ozonolysis composite material powder.

The catalytic performance test is the same as in Example 1. The test results show that the composite catalyst prepared in this comparative example has a catalytic decomposition efficiency of 45% for 100 ppm of ozone at room temperature.

From the above examples and comparative example 1, it can be seen that the catalytic decomposition ability of the composite catalyst treated with ultrafine grinding to ozone is significantly greater than that of the composite catalyst without ultrafine grinding treatment. This may be because during the ultra-fine grinding process, each oxide was fully dispersed and fused with each other in the high-speed, high-energy grinding process, thereby greatly enhancing the catalytic decomposition ability of the composite catalyst.

The above content is only a preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. limits.

Claims (10)

1. a preparation method for the composite catalyst of ozone decomposition, said method comprising the steps of: by permanganate, Mn^II Salt and Cu^IISalt the most each dissolves and obtains three kinds of saline solution；It is mixed and stirred for these three saline solution rapidly carrying out oxidoreduction Reaction, is then passed through filtering, cleaning the filtering residue obtaining composite oxides；Described filtering residue addition water is mixed, forms filtering residue With the suspension of water, described suspension is carried out Ultrafine Grinding process, be fully ground after described suspension again through lyophilization work Skill, i.e. obtains the composite catalyst of described ozone decomposition.

The preparation method of the composite catalyst of ozone decomposition the most according to claim 1, described permanganate selects height Potassium manganate.

The preparation method of the composite catalyst of ozone decomposition the most according to claim 1 and 2, described Mn^IISulfur selected by salt Any one or more in acid manganese, manganese nitrate, manganese carbonate, manganese chloride.

4. according to the preparation method of the composite catalyst of the ozone decomposition described in any one of claim 1-3, described Cu^IISalt can To select one or more in copper sulfate, copper nitrate and copper chloride.

5. according to the preparation method of the composite catalyst of the ozone decomposition described in any one of claim 1-4, described permanganic acid Saline solution compound concentration is 10-30wt%, preferably 10-25wt%.

6. according to the preparation method of the composite catalyst of the ozone decomposition described in any one of claim 1-5, described Mn^IISalt is molten Liquid compound concentration is 5-30wt%, preferably 10-20wt%.

7. according to the preparation method of the composite catalyst of the ozone decomposition described in any one of claim 1-6, described Cu^IISalt is molten Liquid compound concentration is 3-30wt%, preferably 8-20wt%.

8. according to the preparation method of the composite catalyst of the ozone decomposition described in any one of claim 1-7, described Mn^IISalt, Permanganate and Cu^IIThe mol ratio of salt is 1: (2.1-4): (0.05-1), and wherein optimum ratio is 1: (2.2-3.5): (0.2- 1)。

9., according to the preparation method of the composite catalyst of the ozone decomposition described in any one of claim 1-8, described oxidation is also The temperature range of former reaction is-10-99 DEG C, preferably 10-90 DEG C.

10., according to the preparation method of the composite catalyst of the ozone decomposition described in any one of claim 1-9, described oxidation is also The time range of former reaction is 0.5-30h, preferably 0.5-20h.