JPH09274031A - Ozone removing agent and nitrogen dioxide detection pipe using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ozone removing agent for selectively removing only ozone from mixed gas containing ozone and nitrogen dioxide without exerting effect on nitrogen dioxide and a nitrogen dioxide detection pipe for accurately and simply measuring the concn. of nitrogen dioxide in the mixed gas. SOLUTION: An ozone removing agent selectively removes only ozone from mixed gas containing ozone and nitrogen dioxide without exerting effect on itrogen dioxide. Therefore, tetraethylrhodamine is supported on a porous carrier in an amt. of 0.01% or more by wt. of the porous carrier. A nitrogen dioxide detection pipe is obtained by filling a glass pipe with the ozone removing agent and a nitrogen dioxide detection agent colored by nitrogen dioxide and both ends thereof are heat-sealed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ozone remover for selectively removing ozone from a mixed gas containing nitrogen dioxide and ozone, and a nitrogen dioxide detector tube using the same. More specifically, the present invention relates to an ozone removing agent in which tetraethylrhodamine (rhodamine B) is supported on a porous carrier, and a nitrogen dioxide detecting tube filled with the ozone removing agent and the nitrogen dioxide detecting agent.

[0002]

2. Description of the Related Art Recently, indoor environmental pollution and atmospheric environmental pollution due to nitrogen dioxide have become a problem. The cause of indoor environmental pollution is the gas containing nitrogen dioxide discharged from heating appliances or gas cooking appliances except electric stoves, and the nitrogen dioxide concentration reaches a maximum of 0.3 to 0.4 ppm, which is an environmental standard value. It is well above 0.06 ppm.
Air pollution is caused by gases containing nitrogen dioxide such as automobile exhaust gas and factory exhaust gas. These contaminant gases are usually present as a gas mixture containing nitrogen dioxide and ozone together. Nitrogen dioxide and ozone are both oxidizing substances and show similar chemical properties. Therefore, the usual nitrogen dioxide detection agent is not only nitrogen dioxide,
Since it also reacts with ozone and a detector tube using such a detector displays higher than the actual nitrogen dioxide concentration, accurate measurement cannot be performed. Ozone must be removed to eliminate ozone interference in the analysis of nitrogen dioxide. Examples of methods for effectively removing ozone from such a mixed gas to measure the nitrogen dioxide concentration include Salzman absorption spectrometry and ion chromatography, but these are complicated and expensive, and further, in Requires analysis. Therefore, it is desirable that the nitrogen dioxide concentration of such a mixed gas can be accurately measured in the field by a simple measuring method.
As substances capable of removing ozone by reaction, potassium iodide, indigo, and the like have been conventionally known. However, all the drugs obtained by supporting these on a porous carrier also react with nitrogen dioxide. Therefore, these drugs cannot be used for nitrogen dioxide detector tubes.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ozone removing agent which selectively removes only ozone from a mixed gas containing nitrogen dioxide and ozone without affecting the nitrogen dioxide. . A further object of the present invention is to provide a nitrogen dioxide detector tube for detecting and measuring the nitrogen dioxide concentration of such a mixed gas in an accurate and simple manner.

[0004]

According to the present invention, the ozone removing agent is an ozone removing agent prepared by supporting tetraethylrhodamine on the porous carrier in an amount of 0.01% or more based on the weight of the porous carrier. Can be provided.
Further, the nitrogen dioxide detector tube of the present invention for measuring the concentration of nitrogen dioxide in a mixed gas containing ozone and nitrogen dioxide is obtained by filling a glass tube with the ozone remover and the nitrogen dioxide detector agent which is colored with nitrogen dioxide. Provided by. Here, this detector tube selectively removes only ozone in the mixed gas with an ozone remover,
It is characterized in that the interference due to the reaction between the nitrogen dioxide detection agent and ozone is eliminated to improve the measurement accuracy.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The reagent for the ozone remover of the present invention is tetraethylrhodamine. Unlike conventional reagents such as potassium iodide and indigo, tetraethylrhodamine reacts only with ozone without reacting with nitrogen dioxide.

In order to bring tetraethylrhodamine into the form of a scavenger, a carrier carrying tetraethylrhodamine is necessary. As the carrier, silica gel, John-Manvill
diatomaceous earth, such as Celite ™, available from Company e
Also, porous materials such as molecular sieves are used, and silica gel is particularly suitable. Silica gel is classified into A type, B type and ID type according to the difference in surface area, pore volume and the like. If the surface area of the silica gel is too small and the pore volume is too large, ozone will pass without reacting with tetraethylrhodamine. Conversely, if the silica gel surface area is too large and the pore volume is too small, nitrogen dioxide will be adsorbed on the silica gel. Accurate measurement is difficult. The surface area of silica gel includes, but is not limited to, 450-5
It is preferably 80 m ² / g, i.e. type B falling within this range is particularly preferred. The amount of tetraethylrhodamine supported on the porous carrier is 0.0 based on the weight of the carrier.
It is 1% or more.

The reagents for the nitrogen dioxide detecting agent of the present invention include orthotolidine, diphenylbenzidine, and 3,3 ′.
-Dimethylnaphthidine may be used. Since 3'3-dimethylnaphthidine has several times higher sensitivity than orthotolidine, 3,3'-dimethylnaphthidine is particularly preferable for applications requiring high sensitivity such as atmospheric environment measurement. The amount of the nitrogen dioxide detecting agent is not particularly limited, but is usually 0.0003 to 0.0006% based on the weight of the carrier. If it is less than 0.0003%, the sensitivity is improved, but the coloring becomes thin, and if it exceeds 0.0006%, the sensitivity is deteriorated.

FIG. 1 shows an embodiment of the nitrogen dioxide detector tube of the present invention. One end of the glass tube is fusion-sealed, and then, as shown in the figure, 1) polypropylene stopper, 2) nitrogen dioxide detecting agent, 3) blue sand for detecting agent protection, 4) ozone removing agent and 5) cotton stopper. The detector tube can be manufactured by filling in a glass tube in this order and finally fusing the other end. In addition, the area of the nitrogen dioxide sensing agent on the glass tube 2)
It is possible to display the nitrogen dioxide concentration by marking a scale and transmitting a predetermined amount of mixed gas. When using, destroy both ends of the glass tube to open it,
The nitrogen dioxide concentration can be easily measured by passing a predetermined amount of mixed gas at a predetermined rate.

[0009]

Next, examples illustrating the present invention will be shown. Example 1 0.1 g of tetraethylrhodamine was added and dissolved in 300 ml of an ethanol solvent. This was added to 300 g of 30-mesh silica gel type B, and the solvent was completely removed under vacuum in a 100 ° C. water bath to produce an ozone remover. The fluorescent red particles were enclosed in a glass tube having an inner diameter of 3.5 to 3.6 mm. When 100 ml of a mixed gas containing 0.6 ppm of nitrogen dioxide and 0.6 ppm of ozone was bubbled through a glass tube containing the scavenger, ozone was selectively removed, and the concentration of nitrogen dioxide did not change (FIG. 2). And FIG. 4).

Comparative Example A The same test as in Example 1 was carried out using Indigo, which is a conventional ozone remover. 0.5 g of indigo was added and dissolved in 300 ml of an ethanol solvent. This was added to 200 g of 30-mesh silica gel type B, and the solvent was completely removed under vacuum in a 100 ° C. water bath to produce an ozone remover. This was enclosed in a glass tube having an inner diameter of 3.5 to 3.6 mm. In a glass tube containing this remover, nitrogen dioxide 0.6 p
mixed gas containing pm and 0.6 ppm ozone 10
When 0 ml was aerated, nitrogen dioxide was removed together with ozone (see FIG. 3).

Comparing FIG. 2 and FIG. 3, it can be seen that tetraethylrhodamine is excellent as a reagent for the ozone removing agent used in the nitrogen dioxide detector tube of the present invention.

Example 2 0.05 g of 3,3'-dimethylnaphthidine was dissolved in 100 ml of an ethanol solvent. 40 ml of this solution 1 ml
It was added to 100 g of 60-mesh silica sand and vacuum dried in a water bath at 80 ° C. to produce a nitrogen dioxide detection agent. In a glass tube having one end sealed by fusion, a polypropylene stopper, the nitrogen dioxide detecting agent obtained as described above, blue silica sand for protecting the detecting agent, and an ozone removing agent obtained by the same method as in Example 1 Then, a nitrogen dioxide detector tube was manufactured by filling in the order of and a cotton plug and sealing the other end. The nitrogen dioxide concentration was measured by bubbling 100 ml of a mixed gas containing 0.25 ppm of nitrogen dioxide and 0.1-1.0 ppm of ozone.

Comparative Example B In the same manner as in Example 2, a nitrogen dioxide detector tube was manufactured without adding an ozone remover and measured.

As shown in FIG. 5, it can be seen that the nitrogen dioxide detector tube of the present invention containing the ozone removing agent shows accurate measurement results.

[Brief description of drawings]

FIG. 1 is a schematic view showing one embodiment of a nitrogen dioxide detecting tube of the present invention.

FIG. 2 is a graph showing the nitrogen dioxide concentration after passing through an ozone removing agent containing tetraethylrhodamine of the present invention.

FIG. 3 is a graph showing the nitrogen dioxide concentration after passing through the ozone removing agent containing indigo of the present invention.

FIG. 4 is a graph showing the nitrogen dioxide concentration after passing through an ozone removing agent containing tetraethylrhodamine of the present invention.

FIG. 5 is a graph showing a comparison of readings of a nitrogen dioxide detector tube containing the ozone removing agent of the present invention and a detector tube not containing the same.

[Explanation of symbols]

 1 ... Polypropylene stopper 2 ... Nitrogen dioxide 3 ... Blue silica sand for protecting detection agent 4 ... Ozone detection agent 5 ... Cotton plug

Claims (3)

[Claims] 1. An ozone removing agent for selectively removing only ozone from a mixed gas containing ozone and nitrogen dioxide without affecting the nitrogen dioxide, which is 0.01 based on the weight of the porous carrier. %, An ozone removing agent in which tetraethylrhodamine is supported on the porous carrier in an amount of at least%. 2. An ozone removing tube in which the ozone removing agent according to claim 1 is filled in a glass tube or a resin tube and both ends are sealed. 3. A nitrogen dioxide detector tube for measuring the concentration of nitrogen dioxide in a mixed gas containing ozone and nitrogen dioxide, wherein the detector tube is colored with the ozone remover and nitrogen dioxide according to claim 1. Nitrogen dioxide detection tube in which a nitrogen dioxide detection agent is filled in a glass tube and both ends thereof are sealed.