CN102138703A - Top modified transitional metal carbon hollow pipe material, and preparation method and application thereof - Google Patents

Abstract

The invention relates to a carbon hollow tube material with a top-modified transition metal and its preparation method and application. The polyhydroxy polymer and the organic compound of the transition metal are put into a stainless steel autoclave, sealed and placed in a high-temperature furnace for 30-55 minutes to be produced. Raise the room temperature to 320-500°C and keep at this temperature for 9-15 hours; after cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum dry to obtain transition metal iron and cobalt Or a material in which nickel gathers at one end of a carbon hollow tube. The material of the invention has good adsorption performance, simple preparation method, easy control of preparation conditions, and good preparation reproducibility of the top-modified transition metal carbon nanotubes.

Description

Carbon hollow tube material with top modified transition metal and its preparation method and application

technical field

The invention relates to a carbon hollow tube material and its application in cigarettes, belonging to the technical field of tobacco.

Background technique

Smoking and health are issues of general concern to people, and the impact of harmful components such as hydrocyanic acid in mainstream cigarette smoke on human health has attracted much attention. Therefore, reducing the harmful components in the smoke, reducing the harm of smoking, and improving the quality and safety of cigarette products are issues that the tobacco industry must solve. High-quality, safe and low-hazard cigarettes have become the development trend of international cigarettes. The previous research work shows that: due to the complex sources of harmful components in cigarette smoke, tar reduction can only partially suppress the harmful components in cigarette smoke, and the harmful components in smoke cannot be effectively removed only by reducing the amount of tar in cigarettes. Therefore, it is very necessary to carry out reduction work for a certain harmful component in the flue gas. As a newly developed material, carbon hollow tube has many different physical and chemical properties from traditional materials due to its special structure, and its wide application prospects. The material has the following characteristics: hollow pore structure, low density, high porosity, large specific surface and can allow liquid or gas to pass through selectively, and has excellent adsorption and catalytic performance, so carbon hollow tubes are widely used in various functional and structural materials.

Patent CN101618867A discloses a carbon hollow tube of transition metal ions is a carbon hollow material, which is fully mixed with a sulfur-containing growth promoter in a gaseous state through the rapid sublimation of an organometallic compound catalyst, and then enters the reaction zone under the entrainment of buffer gas reaction, the patent obtained is a carbon hollow material decorated with metal particles around carbon nanotubes. The preparation method of this material is complicated and the preparation conditions are harsh.

Contents of the invention

The object of the present invention is to provide a carbon hollow tube material whose top end is modified with a transition metal, as well as its preparation method and application.

The technical scheme that the present invention takes is:

A carbon hollow tube material modified with a transition metal at the top, and the transition metal iron, cobalt or nickel is gathered at one end of the carbon hollow tube.

The preparation method of the carbon hollow tube material with the transition metal modified at the top, the steps are as follows:

Put the transition metal organic compound and polyol in a stainless steel autoclave, seal it and place it in a high-temperature furnace to raise the temperature from room temperature to 320-500°C within 30-55 minutes, and keep it at this temperature for 9-15 hours; cool After reaching room temperature, rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum dry to obtain a carbon hollow tube with a top modified transition metal.

The mass ratio of the polyhydroxy polymer to the transition metal organic compound ranges from 2:1 to 6:1.

The organic compound of transition metal is oxalate or acetate of transition metal.

The polyhydroxy polymer is polyvinyl alcohol or polyethylene glycol.

The application of the carbon hollow tube material with the top end modified transition metal as filter material in cigarette filter tip.

A cigarette containing the carbon hollow tube material of the top-modified transition metal in the filter tip.

The advantages of the carbon hollow tube material with the top modified transition metal of the present invention: high porosity, large specific surface and can allow selective adsorption of liquid or gas, because one end of the carbon hollow tube material with the top modified transition metal is open, and one end is modified The transition metal is closed, and this structure makes it have special adsorption properties, and can also be used as a carrier for the transition metal. When the transition metal is modified to one end of the carbon hollow tube material, since the transition metal particles enter the nanoscale, the size confinement will cause quantum effect, leading to its excellent adsorption and catalytic properties, which can effectively reduce the harmful component of hydrocyanic acid in mainstream cigarette smoke.

The advantages of the method for preparing the carbon hollow tube material with a top-modified transition metal are that the preparation method is simple, the preparation conditions are easy to control, and the preparation of the carbon nanotube with a top-modified transition metal has good reproducibility.

The filter tip of the present invention contains the cigarette of the carbon hollow tube material with the top-modified transition metal, which can improve the adsorption effect of the mouthpiece on the harmful component hydrocyanic acid in the smoke, and reduce the content of the harmful component hydrogen cyanide in the cigarette smoke. The cigarette style remains unchanged, improving the safety of cigarette smoking. The experimental results show that the cigarette tip with the carbon hollow tubes modified with iron, cobalt and nickel at the top can significantly reduce the content of the harmful component hydrocyanic acid in the smoke, and the carbon hollow tube with the top modified iron has the effect of reducing hydrocyanic acid Preferably, as the addition amount of the carbon hollow tube modified with iron at the top increases, the amount of hydrocyanic acid in the flue gas decreases, and the content of hydrocyanic acid in the flue gas decreases by 14.6-43%.

Description of drawings

Figure 1 is the morphology analysis diagram of carbon hollow tubes with transition metals on top, (A) SEM photo of carbon hollow tubes with iron top modification, (B) SEM photo of carbon hollow tubes with cobalt top modification, (C) nickel top modification SEM photos of carbon hollow tubes;

Figure 2 is a thermogravimetric analysis diagram of a carbon hollow tube material with a top-modified transition metal;

Fig. 3 is a structural diagram of a composite cigarette filter containing the carbon hollow tube material with the transition metal modified at the top; wherein: 1 is tow, and 2 is an added layer of the carbon hollow tube material with the transition metal modified at the top.

Detailed ways

All reagents were of analytical grade and purchased from Shanghai Sinopharm Group. Automatic analyzer AA3 (BranLuebbe, Germany), H-7000 transmission electron microscope (Hitachi, Japan), high-resolution transmission electron microscope JEM-2100 (Electronics, Japan), smoking machine SM450 (Cerulean, UK).

Example 1

Synthesis of carbon hollow tubes modified with iron at the top: 25 grams of polyvinyl alcohol and 10 grams of ferric oxalate were uniformly mixed, placed in a stainless steel autoclave, sealed and placed in a high-temperature furnace. Keep at high temperature for 10 hours, after cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum dry at 40°C for 4 hours to obtain a carbon hollow tube with iron modified on the top, the morphology is shown in the figure 1(A).

Example 2

Synthesis of carbon hollow tubes modified with iron at the top: 50 grams of polyvinyl alcohol and 20 grams of ferric oxalate were uniformly mixed, placed in a stainless steel autoclave, sealed and placed in a high-temperature furnace. Keep at temperature for 15 hours, after cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum dry at 40°C for 4 hours to obtain a carbon hollow tube with iron modified on the top.

Example 3

Synthesis of carbon hollow tubes modified with iron at the top: 30 grams of polyethylene glycol and 12 grams of ferric oxalate were uniformly mixed, placed in a stainless steel autoclave, sealed and placed in a high-temperature furnace, heated from room temperature to 350 ° C within 30 minutes, and Keep at this temperature for 12 hours, after cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum dry at 40°C for 4 hours to obtain a carbon hollow tube with iron-top modification.

Example 4

Synthesis of carbon hollow tubes modified with nickel at the top: put 30 grams of polyvinyl alcohol and 6 grams of nickel oxalate precursor into a stainless steel autoclave, seal it and place it in a high-temperature furnace. Leave on for 12 hours. After cooling to room temperature, rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum-dry at 40°C for 4 hours to obtain a carbon hollow tube with a top-modified nickel. The morphology is shown in Figure 1(C).

Example 5

Synthesis of carbon hollow tubes modified with nickel at the top: Put 50 grams of polyvinyl alcohol and 8 grams of nickel oxalate precursor into a stainless steel autoclave, seal it and place it in a high-temperature furnace. Leave on for 10 hours. After cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum-dry at 40°C for 4 hours to obtain a carbon hollow tube with a top-modified nickel.

Example 6

Synthesis of carbon hollow tubes modified with nickel at the top: Put 40 grams of polyethylene glycol and 7 grams of nickel oxalate precursor into a stainless steel autoclave, seal it, place it in a high-temperature furnace, and raise the temperature from room temperature to 450 ° C within 50 minutes, and then The temperature was maintained for 10 hours. After cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum-dry at 40°C for 4 hours to obtain a carbon hollow tube with a top-modified nickel.

Example 7

Synthesis of cobalt-topped carbon hollow tubes: Put 25 grams of polyvinyl alcohol and 4 grams of cobalt oxalate precursor into a stainless steel autoclave, seal it and place it in a high-temperature furnace. Leaves on for 11 hours. After cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum-dry at 40°C for 4 hours to obtain a carbon hollow tube with a top-modified cobalt, as shown in Figure 1(B).

Example 8

Synthesis of cobalt-topped carbon hollow tubes: 35 grams of polyethylene glycol and 6 grams of cobalt oxalate precursor were placed in a stainless steel autoclave, sealed and placed in a high-temperature furnace. The temperature was raised from room temperature to 500 ° C within 55 minutes, and the The temperature was maintained for 9 hours. After cooling to room temperature, first rinse with absolute ethanol, then rinse with distilled water to remove impurities, and then vacuum-dry at 40°C for 4 hours to obtain a carbon hollow tube with a top-modified cobalt.

Performance Testing:

The morphology of the obtained top-modified carbon hollow tubes of iron, cobalt, and nickel was analyzed and characterized by a transmission electron microscope (SEM) (as shown in Figure 1).

In the air, the thermogravimetric analysis of carbon hollow tubes with iron, cobalt and nickel at the top was carried out, and it was found that the carbon hollow tubes with nickel at the top had the best thermal stability, and obvious weight loss was observed when the temperature reached 630 °C ( See Figure 2). The thermal stability of carbon hollow tubes modified with cobalt at the top is next, and the apparent weight loss temperature is 550 °C. The carbon hollow tubes modified with iron at the top have the worst thermal stability, and the apparent weight loss temperature is 430℃. The carbon hollow tubes decorated with iron, cobalt, and nickel at the top have a weight loss range of 430-630°C, and can exist stably in the air before 430°C, which shows that the carbon hollow tubes with iron, cobalt, and nickel modified at the top have good thermal stability.

Accurately weigh 0.005 gram, 0.010 gram, 0.015 gram and 0.020 gram of the top-modified carbon hollow tubes of iron, cobalt and nickel respectively, compound them in the filter tip of the finished cigarette, and make the composite filter tip of the novel cigarette (see Figure 3).

Analysis and detection of hydrocyanic acid in cigarette smoke: based on the chromogenic system of isonicotinic acid and 1,3-dimethylbarbituric acid, the 600nm photometric detection of hydrocyanic acid is performed on a continuous flow analyzer, and the mainstream of cigarettes is detected by a continuous flow method Hydrocyanic acid in flue gas, this method is safe and environmentally friendly, simple to operate, high in sensitivity and good in repeatability.

(1) Carbon hollow tubes modified by different metals have the effect of reducing hydrocyanic acid in flue gas

Accurately weigh 0.010 grams of top-modified iron, cobalt, and nickel three carbon hollow tubes as additives for cigarette tip rods to make composite filters, as shown in Figure 3. The content of hydrocyanic acid in the smoke of each cigarette added with the top-modified iron, cobalt and nickel three carbon hollow tube composite cigarette tip rods is shown in Table 1. From this table, it can be concluded that the top-modified iron, cobalt and nickel three carbon hollow The tubes have obvious effects on reducing the content of hydrocyanic acid in the flue gas, and the carbon hollow tube with the top modified iron has the best effect on reducing the content of hydrocyanic acid in the flue gas. It can be deduced that the carbon hollow tubes modified with iron at the top have a better ability to adsorb hydrogen cyanide in flue gas due to the stronger coordination ability between iron ions and CN-.

Table 1: Hydrocyanic acid content in flue gas of carbon hollow tubes with different metals added to the top of the filter

name Hydrocyanic acid (ug/branch) Original cigarette 139.3 Add 0.010 grams of top modified iron carbon hollow tube compound filter cigarettes 99.6 Add 0.010 grams of top-modified cobalt carbon hollow tube composite filter cigarettes 109.4 Add 0.010g top-modified nickel carbon hollow tube composite filter cigarettes 119.6

(2) Effect of carbon hollow tubes with different amounts of top-modified iron on the reduction of hydrocyanic acid in flue gas

Accurately weigh 0.005 gram, 0.010 gram, 0.015 gram and 0.020 gram of top-modified iron carbon hollow tubes respectively, compound them in the filter tip of finished cigarettes, and measure the content of hydrocyanic acid in Table 2. The content of hydrocyanic acid in the flue gas decreases sequentially with the addition of iron-modified carbon hollow tubes, which shows that with the increase of the number of iron-modified carbon hollow tubes at the top, the number of iron active sites that adsorb hydrocyanic acid in the flue gas increases , the hydrocyanic acid in the flue gas decreases with the increase of the amount of carbon hollow tubes modified with iron at the top, but when the amount of carbon hollow tubes with iron modified at the top exceeds 0.015 g, more amount of carbon hollow tubes with iron modified at the top is added , will lead to the increase of the resistance of the cigarette, which will affect the smoking and taste of the cigarette. Comprehensive consideration: the addition of 0.015 g of top-modified iron carbon hollow tube per cigarette is the best for reducing the content of hydrogen cyanide in smoke.

Table 2: Hydrocyanic acid content in carbon hollow tube flue gas with different amounts of top-modified iron added to the filter

name Hydrocyanic acid (ug/branch) Original cigarette 139.3 Add 0.005 grams of top modified iron carbon hollow tube composite filter cigarettes 110.8 Add 0.010 grams of top modified iron carbon hollow tube compound filter cigarettes 99.6 Add 0.015 grams of top modified iron carbon hollow tube composite filter cigarettes 90.5 Add 0.020 grams of top modified iron carbon hollow tube composite filter cigarettes 78.9

A comparative study of carbon hollow tubes with iron modified at the top, carbon hollow tubes with cobalt modified at the top, and carbon hollow tubes with nickel modified at the top. Three kinds of carbon hollow tubes used as additives for cigarette tip rods can significantly improve the hydrogen resistance of cigarette filters. The adsorption effect of harmful components of cyanic acid can effectively reduce the content of hydrogen cyanide in cigarette smoke. At the same time, it is found that the carbon hollow tube with iron modified on the top can reduce the harmful component hydrogen in smoke because iron ions have a stronger ability to coordinate with CN- The effect of cyanic acid is the best. With the increase of the carbon hollow tube with iron modified on the top, the content of the harmful component hydrocyanic acid in the smoke gradually decreases, with a minimum reduction of 43%. Therefore, the carbon hollow tube modified with iron at the top is added to the composite mouth of the cigarette The rod is used to selectively reduce the content of hydrocyanic acid, a harmful component in smoke, and has broad application prospects in reducing harm and tar in cigarette smoke.

Claims (7)

1. the carbon hollow pipe material of transition metal is modified on the top, it is characterized in that transition metal iron, cobalt or nickel accumulate in an end of carbon hollow pipe.

2. the carbon hollow tube preparation method for material of transition metal is modified on top according to claim 1, it is characterized in that step is as follows:

The organic compound and the polyhydroxylated polymer of transition metal are put into stainless steel autoclave, and sealing is placed in the high temperature furnace and is warmed up to 320-500 ℃ by room temperature in 30-55min, and keeps 9-15 hour in this temperature; After being cooled to room temperature, use absolute ethyl alcohol drip washing earlier, remove impurity with distilled water drip washing again, vacuum drying then promptly obtains the carbon hollow pipe material that transition metal is modified on the top.

3. the preparation method of the carbon hollow pipe material of transition metal is modified on top according to claim 2, it is characterized in that described polyhydroxylated polymer is 2: 1～6: 1 with the quality of the organic compound of transition metal than scope.

4. the preparation method of the carbon hollow pipe material of transition metal is modified on top according to claim 2, it is characterized in that the organic compound of described transition metal is the oxalates or the acetate of transition metal.

5. the preparation method of the carbon hollow pipe material of transition metal is modified on top according to claim 2, it is characterized in that described polyhydroxylated polymer is polyvinyl alcohol or polyethylene glycol.

The described top of claim 1 modify transition metal carbon hollow pipe material in cigaratte filter as the application of filtering material.

7. contain the cigarette that the carbon hollow pipe material of transition metal is modified on the described top of claim 1 in the filter tip.

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