JPH01302156A - Ozone scrubber - Google Patents

Abstract

PURPOSE:To enable accurate measurement of a concentration of ozone in a sample gas, by using an ion exchange resin into which is introduced an ion exchange group having an electron attracting property on the surface of a copolymer-based high polymer carrier of styrene and divinyl benzene. CONSTITUTION:A glass or metal tube 16 having an inlet tube 14 and an outlet tube 15 at both ends thereof is filled with an ozone treating agent 17 while filters 18 and 18 are arranged covering a path of the inlet tube 14 and the outlet tube 15. Here, an ion exchange resin into which is introduced an ion exchange group having an electron attracting property on the surface of a copolymer based high polymer carrier of styrene and divinyl benzene is used as ozone treating agent. This enables a sample gas to be brought into contact wit the ozone treating agent accurately thereby assuring an accurate measurement of concentration.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ozone scrubber that decomposes ozone in a gas, and more specifically, it is suitably used in an ultraviolet absorption type ozone concentration meter and This article relates to an ozone scrubber that enables accurate ozone concentration measurement.

[Conventional technology]

Measuring the ozone concentration in gas using the ultraviolet absorption method is based on the principle that ultraviolet rays of a specific wavelength are absorbed by ozone, and the absorption rate is proportional to the ozone concentration. However, there is an absorption band for ultraviolet rays in the atmosphere. In addition to ozone, the gas components include NOX and SOX.

There are many things such as hydrocarbons.

For this reason, when measuring only the ozone concentration in gas by the ultraviolet absorption method, it is common practice to configure the measuring device as shown in FIG. 2.

That is, in FIG. 2, 1 is a sample gas inlet 10. 2 is a sample gas distribution pipe connected to the sample gas inlet 1, 3 is a three-way switching valve installed in the sample gas distribution pipe 2, and 4 is a three-way valve with one end connected to the sample gas inlet 1. A bypass pipe 5 is connected to the passage port of the switching valve 3 and the other end is connected to the downstream side of the three-way switching valve 3 of the sample gas distribution pipe 2, and a bypass pipe 5 has an ozonating agent therein. An ozone scrubber, 6 is an ultraviolet absorption cell installed in the sample gas flow pipe 2, 7 is an ultraviolet lamp installed in the ultraviolet absorption cell 6, 8 is a detector attached to the ultraviolet absorption cell 6, and 9 is a detector a comparison calculation circuit connected to 8; 10.
Reference numerals 11 and 12 indicate a flow meter, a pump, and a pipe installed in the sample gas distribution tube 2, respectively, and 12 indicates a sample gas outlet to which the outflow end of the sample gas introduction tube 2 is connected.

When measuring the ozone concentration in a sample gas using the above device, first the sample gas is sucked at a constant flow rate into the flow pipe 2 from the inlet 1 by operating the pump 11, and then passed through the bypass pipe 4 by operating the three-way switching valve 3. The sample gas is introduced directly into the cell 6 without the need for a sample gas. When the sample gas is irradiated with ultraviolet rays of a specific wavelength in cell 6, the sample gas absorbs ultraviolet rays proportional to the concentration of ozone and other coexisting components that have absorption bands in the ultraviolet rays in the gas. is detected by the detector 8, converted into an electric signal corresponding to its intensity, and stored in the comparison calculation circuit 9. Note that the sample gas that has flowed out of the cell 6 is passed through the flowmeter 10, pump 11, and pipe 1.
2 and is discharged from the discharge port 13. Next, the three-way switching valve 3 is switched, the sample gas is introduced into the cell 6 through the bypass pipe 4, and measurement is performed in the same manner as above. In this case, since the ozone in the sample gas is decomposed by the ozone scrubber 5, ultraviolet light proportional to the concentration of coexisting components other than ozone is absorbed, and the intensity of this attenuated ultraviolet light is converted into an electrical signal by the detector 10. . Then, the former electric signal of ultraviolet intensity attenuated by ozone and other coexisting components and the latter electric signal of ultraviolet intensity attenuated only by coexisting components are compared and calculated in a comparison calculation circuit 9, and the difference corresponds to the ozone concentration. By repeating the above operation, the ozone concentration in the sample gas is intermittently measured.

Since the above measurement device uses a single ultraviolet absorption cell, it is independent of changes in device performance due to dirt on the cell or mirror, fluctuations in the power supply voltage of the ultraviolet lamp, changes in light intensity over time, changes in ambient temperature, etc. Measurements can always be performed under the same conditions, which is very advantageous, and high-sensitivity measurements are also possible.

However, in this case, in order to accurately measure ozone concentration using the ultraviolet absorption method, the performance of the ozone scrubber is extremely important. Ideally, coexisting components that have absorption should not be changed at all.

[Problem to be solved by the invention]

In ozone concentration measurement using the ultraviolet absorption method described above, a 254 nm ultraviolet light source is usually used.
The gas in the atmosphere that absorbs 254 nm ultraviolet light is S.
Hydrocarbons such as O□, NO□, and double bonds are present. In reality, SOx and hydrocarbons are problematic as interfering gases; for example, benzene is said to have an absorption coefficient of 4% of ozone at 254n+s.

On the other hand, as a means to decompose ozone, there is a method of adsorbing and decomposing spores with activated carbon (Japanese Patent Application Laid-Open No. 83910/1983).
JP-A-51-29176) and a method of catalytically decomposing ozone with a metal oxide such as manganese dioxide (see JP-A-51-29176) are conventionally known.

However, with the method of using activated carbon or metal oxides as the ozone treatment agent in an ozone scrubber, not only ozone but also hydrocarbons such as benzene that absorb at a wavelength of 254 nm are partially adsorbed or decomposed by the ozone treatment agent. Therefore, there is a problem in that these methods cannot accurately measure ozone concentration.

On the other hand, as a means to solve the above problems,
A thin layer of activated carbon or metal oxide such as manganese dioxide is applied as an ozone treatment agent to the surface of a honeycomb-shaped filter.
It has been proposed to incorporate the expanded product into an ozone scrubber and pass the sample gas through the filter mentioned above.This makes it possible to perform the necessary adsorption or decomposition treatment on ozone, and also to prevent the coexistence of other hydrocarbons, etc. It is said that the gas components can pass through the filter without being affected by the ozone treatment agent in any way.

However, this method requires multiple filter shapes and requires coating with an ozone treatment agent.
As a result, the measuring equipment becomes expensive.

Also, even when using such a special filter,
The current situation is that when measurements are performed at high humidity, the indicated value of ozone concentration decreases, which is considered to be caused by the ozone decomposition performance of the ozone scrubber and the degree of passage of coexisting components.

The present invention was developed in view of the above circumstances, and is capable of reliably decomposing ozone in a sample gas, allowing other coexisting components with ultraviolet absorption to pass through well, and having a simple structure and being manufactured at low cost. The purpose is to provide an ozone scrubber that can.

[Means and effects for solving the problem] The present inventors,
As a result of intensive research to achieve the above objectives, 1. We focused on the addition reaction of ozone to double bond sites in organic unsaturated compounds. That is, when ozone acts on an unsaturated organic compound having an ethylene bond, ozone is added to the double bond to form an osinide as shown in the following formula (1).

This reaction is known as a reaction between a liquid organic unsaturated compound and ozone, but the present inventors have demonstrated that a similar reaction can be performed for a solid polymer compound with a high surface area and a high density of double bond sites. For example, styrene, a copolymer of acrylic acid or methacrylic acid and divinylbenzene, or 2-6-
It has been found that this phenomenon also occurs on polymeric compounds such as porous polymers based on diphenyl-p-phenylene oxide, and that ozone is decomposed on the surfaces of these polymeric compounds.

However, the above copolymer of styrene, acrylic acid or methacrylic acid and divinylbenzene is a porous polymer containing many benzene rings, and therefore, at the same time selectively forms oscinides with ozone, the surface as a whole becomes electron-rich. Due to its attractive nature, it exhibits a weak affinity with electron-donating unsaturated hydrocarbons and tends to adsorb them to some extent. In addition, physical adsorption of SO2, No□, etc. into the micropores is also considered. In contrast, the present inventors replaced benzene rings with ion exchange groups that themselves have electron-withdrawing properties, such as -coon groups, -So, and II groups, on the surface of the carrier made of a porous polymer containing many benzene rings. By introducing it as a group and making it into an ion exchange resin, the electron-withdrawing groups on the entire surface of the polymer compound are reduced, and SO2, No□
In addition to improving the permeability of gases such as, it is possible to reduce the adsorption of hydrocarbons, and it was also found that a similar effect is obtained when a chelate group such as an iminodiacetic acid group is introduced into the carrier. did.

On the other hand, the reaction between the above-mentioned ion exchange resin having a high density of C=C unsaturated bonds and ozone is considered to be similar to the ocinide formation reaction, and is not ozone decomposition due to a catalytic reaction. The ozone treatment capacity of has a lifetime depending on the surface area. In contrast, the present inventors
By introducing an ozone-decomposing catalytic metal onto the ion-exchange resin surface using an ion-exchange group, the catalytic metal is deposited on the ion-exchange resin surface and covers the C═C bond, which allows osinide to be removed. The ozone decomposition layer due to the formation reaction is reduced, and ozone decomposition occurs due to the catalytic decomposition of the catalytic metal, so that ozone decomposition due to ocinide formation and catalytic decomposition due to the catalytic metal proceed simultaneously, extending the life of the ozone treatment agent. At the same time, it has been found that the adsorption of hydrocarbons can be further reduced by coating the C═C bond.

Therefore, the present invention provides the following (a), (b), fc
), (dl and fe) as an ozone treatment agent.

(a) An ion exchange resin obtained by introducing an ion exchange group having electron-withdrawing properties onto the surface of a copolymer carrier of styrene and divinylbenzene.

Yama) An ion exchange resin made by introducing ion exchange groups with electron-withdrawing properties onto the surface of a copolymer carrier of acrylic acid and divinylbenzene.

(c1,!' An ion exchange resin obtained by introducing an ion exchange group having electron-withdrawing properties onto the surface of a copolymer carrier of acrylic acid and divinylbenzene.

(d) A chelate resin obtained by introducing a chelate group onto the surface of a copolymer carrier of styrene and divinylbenzene.

(e) A metal-introduced resin obtained by introducing an ozone-decomposing catalytic metal into the ion-exchange group of the ion-exchange resin of (a), (b), or (c) above.

The present invention will be explained in more detail below.

The ozone scrubber of the present invention uses one or more of the resins (a) to Tel as an ozone treatment agent.

In this case, the copolymer carrier of styrene and divinylbenzene, which is the base material of the resin (al or (b)), preferably has a crosslinking degree of 8 to 20%. The resin in (a) was Amberlyst 15 manufactured by Rohm and Haas, the resin fb) was IRC-50 manufactured by Rohm and Haas, the resin in (c) was MWC-1 manufactured by Dow Chemical, and the resin in (d) was CR-20 manufactured by Mitsubishi Kasei Co., Ltd., etc. can be preferably used.

In addition, in the ozone treatment agents (a), (bl and (c)), as the ion exchange group introduced into the surface of the polymer carrier, one having electron-withdrawing properties is used, and in particular -C
It is preferable to introduce an OOH group, a -SO, H group, an amine group, etc., and an iminodiacetic acid group is preferable as the chelate group to be introduced into the polymer surface in the ozonating agent (d). This reliably reduces the electron-withdrawing property of the surface of the ion exchange resin, improves the permeability of Sol, Not, etc., and reduces the adsorption of hydrocarbons. Incidentally, the ion exchange group and chelate group can be introduced into the polymer carrier by a conventional method.

In addition, (a), (b) in the ozone treatment agent of (el)
or (there is no limitation on the type of catalytic metal introduced into the ion exchange group of the ion exchange resin of c1, but silver, cobalt, iron,
It is desirable to introduce one or more of copper, manganese, and oxides thereof, thereby making it possible to obtain a treatment agent that can reliably catalytically decompose a portion of ozone. Note that metals can be easily introduced into the ion exchange resin by, for example, adding a metal salt to the ion exchange resin, exchanging the functional group to the ionic form of the target ion, and then precipitating it as a metal using an appropriate reducing agent. can be done. Furthermore, this metal can be easily converted into an oxide by oxidizing it by an appropriate method. Specifically, metal-introduced resin into which copper oxide has been introduced can be prepared by, for example, injecting an ion exchange resin into a copper sulfate solution as a metal salt, stirring, washing the ion exchange resin, administering hydrazine, and heating air. can be obtained by exposing it to. Further, a metal-introduced resin into which silver has been introduced can be obtained, for example, by immersing an ion exchange resin in silver nitrate or the like as a metal salt, and then reducing the resin with hydrazine or the like.

The ozone scrubber of the present invention uses the resins (a) to (e) above as an ozone treatment agent, but in this case, there is no particular restriction on the structure of the ozone scrubber, and the ozone-containing gas is brought into contact with the ozone treatment agent. For example, as shown in FIG. 1, an ozone treatment agent 17 is filled in a glass or metal tube 16 having an inlet tube 14 and an outlet tube 15 at both ends. At the same time, it is preferable to have a structure in which a filter 18.18 is disposed to cover the passages of the inlet pipe 14 and the outlet pipe 15, so that the sample gas can be brought into reliable contact with the ozonating agent.

In this case, there are no particular restrictions on the size or amount of the ozone treatment agent of the present invention, but the particle size of the treatment agent is about 0.2 to 0.9 nm, and the amount used is, for example, the ozone scrubber of an atmospheric ozone concentration measuring device. When used as a glass or metal tube with an inner diameter of about 30 to 50 m, it is preferable to fill a glass or metal tube with an amount of about 10 to 20 III.

In addition, when using the scrubber of the present invention, the permeability of hydrocarbons may not be sufficient at room temperature.
By using it while heating it to 0 to 100°C, the passage rate of hydrocarbons can be sufficiently improved.

Next, the effects of the present invention will be specifically illustrated by experimental examples.

[Experiment Example 1] Decomposition of ozone by polymer compounds Part 3
The decomposition of ozone by various polymer compounds was investigated using the measurement system shown in the figure. In Fig. 3, 20 is a sample gas distribution pipe, 21 is an ultraviolet lamp type ozone generator, 22 is a branch pipe, 23 is a monitor chemiluminescent ozone meter, 24.24
25 is a three-way switching valve, 25 is a bypass pipe, 26 is an ozone scrubber filled with polymer compound particles, 27 is an oven for heating the scrubber, and 28 is an ultraviolet absorption type ozone meter. Note that the ozone scrubber 26 has an inner diameter of IQm.
2 polymer compound particles (ozone treatment agent) in a glass tube of m
The flow rate of the sample gas flowing into the flow tube 20 is 21/lll1n1, and the ozone concentration is approximately 400 ppb.
And so. Further, as the polymer compound particles filled in the scrubber 26, those shown in columns 1 to 7 below were used.

Problem 1: Copolymer-based macroporous strong acidic ion exchange resin of styrene and divinylbenzene (ion exchange group:
-5O3H group) (Ambarist 15, manufactured by Rohm and Haas) Floor 2: Copolymer system of methacrylic acid and divinylbenzene Macroporous weakly acidic ion exchange...fat (ion exchange group: -C
OOI+) (Manufactured by Dow Chemical Co., Ltd. C-1) Positive 3: Copolymer chelate resin of styrene and divinylbenzene (chelate group: iminodiacetic acid group) (Mitsubishi Kasei Corporation CR-20) Floor 4: Styrene and divinylbenzene copolymer-based synthetic adsorbent (manufactured by Mitsubishi Kasei Corporation + IP-20) tl&15; copolymer-based packing material for gas chromatography of styrene and divinylbenzene (Vorapack Q) -6; weak copolymer-based adsorbent of acrylic acid and divinylbenzene Acidic ion exchange resin (ion exchange group K00H) (IRC-50 manufactured by Rohm and Haas)! 1m7;
Silver is introduced into the surface of the ion exchange resin of l1kL6.The above-mentioned polymer compound particles are filled into the scrubber 26 as an ozone treatment agent, and the temperature of the ozone treatment agent is set to room temperature or 70°C.
The results of examining the ozone decomposition rate are shown in Table 1 below.

Note that the numerical values are those obtained at a time point of 2° to 30 minutes after the start of the measurement.

From the results in Table 1, we found that styrene, acrylic acid or methacrylic acid, and divinylbenzene copolymer carriers with a large surface area and porous C-C bonds, and ion exchange resins with ion exchange groups introduced onto the surface of these carriers. , a chelate resin into which a chelate group has been introduced, and a metal-introduced resin in which a catalytic metal is introduced onto the surface of the ion-exchange resin are both found to decompose ozone well at room temperature and 70°C. Furthermore, it is found that although the treatment agent 1lh6 has a low ozone decomposition rate, the ozone decomposition rate is improved by introducing silver (N(L7)).

[Experimental Example 2] Hydrocarbon passage rate of ozonating agent Copper oxide was added to the surface of the ozonating agent of 11hl, 2゜3.4.7 and the ion exchange resin of 1 using the measuring system shown in Figure 4. The hydrocarbon passage rate of the ozone treatment agent (NQ8) introduced with the above was investigated at room temperature and 70°C. In Fig. 4, 29 is a sample gas distribution pipe, 30 is a cylinder gas containing five types of hydrocarbons such as benzene, toluene, and ethylbenzene, and 31
is a zero gas introduction pipe, 32 is a mixer, 33.33 is a three-way switching valve, 34 is a bypass pipe, 35 is an ozone scrubber, 3
6 is an oven for heating the ozone scrubber, 37 is a branch pipe,
38 is a hydrocarbon measuring device. The ozone scrubber 35 is a glass tube with an inner diameter of 10 m filled with 2 ml of ozonating agent, the flow rate of the sample gas flowing into the flow tube 29 is 217 ml, and the total hydrocarbon concentration is 7.
71) l) R1 (carbon). For comparison, a similar experiment was conducted using an ozone treatment filter (11h9, described in Japanese Patent Application Laid-Open No. 51-29176) in which a metal oxide as an ozone treatment agent was coated on the surface of a honeycomb filter.

The results are shown in Figure 5.

From the results shown in Figure 5, it is clear that styrene has a strong surface electron-attracting property.
Synthetic adsorbents based on divinylbenzene copolymer (No. 4) are difficult to force through hydrocarbons, but ion exchange resins (Nllll, 2 ), the chelate resin (NQ 3 ) into which iminodiacetic acid groups have been introduced allows hydrocarbons to pass through well, and the metal-introduction resin (N17.8) in which a catalytic metal has been introduced on the ion exchange resin surface has an even higher hydrocarbon passing rate. It can be seen that the temperature has improved to almost 100% at both room temperature and 70°C.

In addition, when the ozone treatment agent is heated, the passage rate of hydrocarbons improves in both cases, and the ion exchange resin of Nal, I'h
Even with the chelate resin No. 3, almost 100% passage was observed. On the other hand, a honeycomb ozone treatment filter (positive 9
) had a poor hydrocarbon passage rate at both room temperature and 70°C.

[Experimental Example 3] Life of ozone treatment agent by oscinide formation reaction
The lifespan of the ion exchange resin (macroporous strongly acidic ion exchange resin based on a copolymer of styrene and divinylbenzene) as an ozone treatment agent was investigated. In this case, the ozone scrubber 5 is filled with the ozone treatment agent No. 1 in the amount shown in Table 2 below, and the ozone concentration in the sample gas is adjusted to 2 to 3 ppm, which is about 10 times the normal atmospheric ozone concentration.
Alternatively, experiments were conducted with the content set at 40 to 50 ppm. The results are shown in Table 2. Note that the life of the ozone treatment agent refers to the time from the start of measurement until the ozone decomposition rate of the treatment agent begins to gradually decrease.

From the results in Table 2, when the ozone concentration is 2 to 3 ppIrl, the filling amount is 2mj! It has a lifespan of 30 minutes or more for 6 tnl, 142 minutes or more for 10 ml, and 40 to 5 minutes.
7 with filling 110n+1 even for 0ppm concentrated ozone
It can be seen that it has a lifespan of 00 minutes or more. From this point of view, it is found that when used at atmospheric level (ozone concentration 10 ppb at high concentration), a lifespan of one year or more can be expected.

〔Effect of the invention〕

As explained above, the ozone scrubber of the present invention can reliably decompose only ozone in a sample gas, and also remove other coexisting components that absorb ultraviolet rays, such as hydrocarbons, SO, NO, etc. It allows gas components to pass through it well, and therefore can be suitably used for ozone decomposition in an ultraviolet absorption ozone meter, making it possible to accurately measure ozone concentration.

In addition, it has a simple structure, the necessary surface area of the processing agent can be easily adjusted by adjusting the amount of processing agent used, and it has various advantages such as easy replacement of deteriorated processing agent. . Furthermore, the production of the treatment agent is extremely simple compared to the case where metal particles or metal oxide particles are formed in a thin layer on a honeycomb-shaped filter or the like.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a schematic view showing an example of an ultraviolet absorption type ozone concentration measuring device, and FIG.
The figure is a schematic diagram showing the measurement system used to measure the ozone decomposition rate of a polymer compound in Experimental Example 1, and Figure 4 is a schematic diagram showing the measurement system used to measure the hydrocarbon passage rate of the ozonating agent in Experimental Example 2. FIG. 5 is a graph showing the hydrocarbon passage rate of various ozonating agents. 5... Ozone scrubber, 17... Ozone treatment agent. Applicant: Denki Kagaku Keiki Co., Ltd. Representative: Takashi Kojima, Patent Attorney Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] 1. The following (a), (b), (c), (d), and (e)
An ozone scrubber characterized by using one or more of the following as an ozone treatment agent. (a) An ion exchange resin obtained by introducing an ion exchange group having electron-withdrawing properties onto the surface of a copolymer carrier of styrene and divinylbenzene. (b) An ion exchange resin obtained by introducing an ion exchange group having electron-withdrawing properties onto the surface of a copolymer carrier of acrylic acid and divinylbenzene. (c) An ion exchange resin obtained by introducing an ion exchange group having electron-withdrawing properties onto the surface of a copolymer carrier of methacrylic acid and divinylbenzene. (d) A chelate resin obtained by introducing a chelate group onto the surface of a copolymer carrier of styrene and divinylbenzene. (e) A metal-introduced resin obtained by introducing an ozone-decomposing catalytic metal into the ion exchange group of the ion exchange resin of (a), (b) or (c) above.