Ozone scrubber, ozone removal method, aldehyde collection device, aldehyde collection method

Abstract

The objective is to eliminate the deliquescence of the ozone adsorbent ozone removal agent in ozone scrubbers, ozone removal methods, aldehyde collection devices, and aldehyde collection methods, thereby suppressing clogging of ozone scrubbers and the appearance of ghost peaks in aldehyde measurement results. [Solution] The ozone adsorbent (8) of the ozone scrubber (2) is made by supporting 3,3',5,5'-tetramethylbenzidine on a diatomaceous earth carrier to create an ozone remover that does not deliquesce even at high temperature and high humidity. The ozone scrubber (2) is connected to an aldehyde collector (3), the aldehyde collector (3) is connected to a suction pump (6), and the suction pump (6) is operated to adsorb ozone in the ozone scrubber (2) and adsorb aldehydes in the aldehyde collector (3).

Description

Technical Field

[0001] The present invention relates to an ozone scrubber and an aldehyde collection device equipped with an ozone scrubber, and further relates to an ozone removal method and an aldehyde collection method which are inventions of methods.

Background Art

[0002] As a method for measuring lower aldehydes (formaldehyde, acetaldehyde, etc.) in an indoor environment or an atmospheric environment, there is a solid collection-HPLC (high performance liquid chromatography) method. That is, aldehydes in the atmosphere are collected by an aldehyde collector having an aldehyde adsorbent and analyzed by HPLC. The analysis results are processed from an electrical signal sent from an analysis instrument or the like and shown in a chromatogram. For the solid collection of aldehydes, an aldehyde collector filled with DNPH (2,4-dinitrophenylhydrazine) impregnated silica gel is generally used.

[0003] In sampling in an atmospheric environment, it has been reported that coexisting ozone has effects such as detection of ghost peaks, reduction of the peak area value of formaldehyde, etc.

[0004] In order to reduce the influence of such ozone, in atmospheric environment measurement, an ozone scrubber having an ozone removing agent is connected to the inlet of an aldehyde collector filled with DNPH impregnated silica gel, and a process for removing ozone is performed. In a conventional ozone scrubber, potassium iodide is widely used as a reaction reagent with ozone. Patent Document 1 discloses an aldehyde collection device in which an ozone scrubber filled with potassium iodide as an ozone removing agent is connected to the inlet of an aldehyde collector.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] The potassium iodide used in conventional ozone scrubbers is hygroscopic. Therefore, when used in rainy weather or in environments with high humidity, the potassium iodide may deliquesce, and the resulting solution may leach out and flow into the aldehyde collector located downstream of the intake air.

[0007] Figure 2(a) shows a chromatogram of measurement results when using an aldehyde collection device equipped with an ozone scrubber filled with potassium iodide. The horizontal axis shows the retention time (min), and the vertical axis shows the response from the detector, i.e., the electrical signal intensity (mAU). A peak P1 of formaldehyde occurs between retention times of 4.5 minutes and 5.0 minutes, and a peak P2 of acetaldehyde occurs between retention times of 6.0 minutes and 6.5 minutes. In addition to these, a ghost peak P3 appears between retention times of 5.5 minutes and 6.0 minutes. The appearance of such a ghost peak P3 is a concern as it may affect the aldehyde analysis results.

[0008] Furthermore, the deliquescent properties of potassium iodide can cause clogging in the ozone scrubber, making suction difficult with the suction pump.

[0009] The object of the present invention is to provide an ozone scrubber and an ozone removal method that can prevent the leaching of ozone removal agents within the ozone scrubber, prevent clogging, and maintain ozone removal performance even in rainy weather or high humidity environments. Furthermore, the object is to provide an aldehyde collection device and collection method that can suppress the appearance of ghost peaks on chromatograms and the reduction of formaldehyde peak area when measuring aldehydes in the atmosphere, even in rainy weather or high humidity environments. [Means for solving the problem]

[0010] To solve the aforementioned problems, the ozone scrubber according to the present invention houses an ozone adsorbent, which consists of 3,3',5,5'-tetramethylbenzidine supported on a diatomaceous earth carrier, within a scrubber case. This eliminates the leaching of the ozone removal agent during rainy weather or in high-humidity environments, preventing clogging of the ozone scrubber and a decrease in its ozone removal performance.

[0011] In one embodiment of an ozone scrubber, the scrubber case is formed from a light-shielding material. This prevents the performance degradation of the ozone adsorbent due to exposure to sunlight.

[0012] The ozone removal method according to the present invention removes ozone from the atmosphere by passing air through an ozone adsorbent, which consists of 3,3',5,5'-tetramethylbenzidine supported on a diatomaceous earth carrier. This provides an effect similar to that obtained when using the aforementioned ozone scrubber.

[0013] In one embodiment of the ozone removal method, the ozone adsorbent is shielded from external light by a light-shielding material. This provides an effect similar to that obtained by constructing the scrubber case with the aforementioned light-shielding material.

[0014] The aldehyde collection device according to the present invention comprises a suction pump for drawing in air, an aldehyde collector directly or indirectly connected to the suction pump, and an ozone scrubber directly or indirectly connected to the suction port of the aldehyde collector. The ozone scrubber is constructed by housing an ozone adsorbent, which consists of 3,3',5,5'-tetramethylbenzidine supported on a diatomaceous earth carrier, within a scrubber case.

[0015] This configuration provides similar effects to those achieved when using the aforementioned ozone scrubber, while also suppressing problems such as the appearance of ghost peaks and a reduction in peak area caused by the ozone removal agent from the ozone scrubber flowing into the aldehyde collector.

[0016] In one embodiment of an aldehyde collection device, silica gel impregnated with DNPH (2,4-dinitrophenylhydrazine) is packed into the aldehyde collector.

[0017] In one embodiment of the aldehyde collection device, the scrubber case is formed from a light-shielding material. This prevents the performance degradation of the ozone adsorbent due to exposure to sunlight.

[0018] The aldehyde collection method according to the present invention comprises the steps of removing ozone from the atmosphere by passing the atmosphere through an ozone adsorbent comprising 3,3',5,5'-tetramethylbenzidine supported on a diatomaceous earth carrier, and drawing the ozone-removed atmosphere into an aldehyde collector to collect the aldehyde.

[0019] This configuration provides the same effects as when using the ozone scrubber described above, while also suppressing problems such as the appearance of ghost peaks and a reduction in peak area caused by the ozone removal agent from the ozone scrubber flowing into the aldehyde collector.

[0020] In one embodiment of the aldehyde collection method, DNPH (2,4-dinitrophenylhydrazine) impregnated silica gel is used in the aldehyde collection step.

[0021] In one embodiment of the aldehyde capture method, the ozone adsorbent is shielded from external light during the ozone removal process. This prevents the performance degradation of the ozone adsorbent due to exposure to sunlight. [Effects of the Invention]

[0022] According to the ozone scrubber and ozone removal method of the present invention, even in rainy weather or in atmospheric environments with high humidity, the ozone removal agent does not deliquesce or dissolve, thereby preventing clogging of the ozone scrubber and maintaining its ozone removal performance.

[0023] Further, according to the aldehyde collection device and the aldehyde collection method of the present invention, similar to the invention of an ozone scrubber or the like, it is possible to prevent clogging of the ozone scrubber, maintain ozone removal performance, and eliminate the influence on the aldehyde collector by the eluting ozone remover as in the prior art. For example, it is possible to suppress a decrease in the peak area of formaldehyde or the generation of ghost peaks.

Brief Description of the Drawings

[0024] [Figure 1] It is an overall view of an aldehyde collection device provided with an ozone scrubber according to an embodiment of the present invention. [Figure 2] It is a chromatogram showing the measurement results of aldehydes collected by the aldehyde collection device. (a) is a chromatogram when an ozone adsorbent loaded with potassium iodide in the prior art is used as an ozone remover, and (b) is a chromatogram when an ozone adsorbent loaded with 3,3',5,5'-tetramethylbenzidine according to the present invention is used as an ozone remover.

Embodiments for Carrying Out the Invention

[0025] [Embodiments of Ozone Scrubber and Aldehyde Collection Device] Embodiments of the ozone scrubber and the aldehyde collection device according to the present invention will be described based on FIGS. 1 and 2.

[0026] FIG. 1 is an overall view of the aldehyde collection device 1. In FIG. 1, the aldehyde collection device 1 includes an ozone scrubber 2, an aldehyde collector 3, and a suction pump 6. A pump connection port 32 of the aldehyde collector 3 is connected to a suction hose 5 connected to the suction pump 6. A pump connection port 22 of the ozone scrubber 2 is connected to an inlet 31 of the aldehyde collector 3.

[0027] The ozone scrubber 2 has an ozone adsorbent 8 housed (filled) inside a cylindrical scrubber case 20, and the case can be replaced in a cartridge-like manner. The direction of arrow A1 is the direction of atmospheric flow, and a lid 23 is attached to the upstream end of the scrubber case 20 in the direction of atmospheric flow A1. The lid 23 has an integrally formed intake cylinder portion 24 through which the atmospheric intake port 21 opens. The pump connection port 22 is formed at the downstream end of the scrubber case 20 in the direction of atmospheric flow A1. Inside the scrubber case 20, the air taken in from the intake port 21 passes through the ozone adsorbent 8 and is discharged from the pump connection port 22, forming a suction path.

[0028] The ozone adsorbent 8 is an important component of the present invention and is constructed by supporting 3,3',5,5'-tetramethylbenzidine on a diatomaceous earth carrier. The scrubber case 20 is made of an opaque material that blocks light, for example, an opaque black resin. This prevents sunlight or other light from reaching the ozone adsorbent 8 from the outside.

[0029] The aldehyde collector 3, like the ozone scrubber 2, is a cartridge type and can be replaced case by case, with an aldehyde adsorbent 38 housed (filled) inside a cylindrical collection case 30. The direction of arrow A2 is the direction of atmospheric flow, and a lid 33 is attached to the upstream end of the aldehyde collector 3 in the direction of atmospheric flow A2. The lid 33 has an intake cylinder portion 34 having the aforementioned intake port 31. The aforementioned pump connection port 32 is formed at the downstream end of the collection case 30 in the direction of atmospheric flow A2. Inside the collection case 30, an intake path is formed in which air taken in from the intake port 31 passes through the aldehyde adsorbent 38 and is discharged from the pump connection port 32.

[0030] The aldehyde adsorbent 38 placed inside the collection case 30 has DNPH (2,4-dinitrophenylhydrazine) supported on a porous carrier such as silica gel.

[0031] In the aldehyde collector 3 (not shown in the diagram), DNPH is desorbed using an organic solvent such as acetonitrile, and this desorbed solution is analyzed using analytical instruments such as HPLC.

[0032] [Ozone removal method and aldehyde collection method] In Figure 1, the aldehyde collection device 1 will be installed at the location where lower aldehydes are to be measured in an indoor or atmospheric environment. However, as a test condition in the laboratory, a mist-like sample gas will be sampled under high temperature and high humidity conditions, for example, at a temperature of 40°C.

[0033] By driving the suction pump 6, air (sample gas) is drawn into the scrubber case 20 from the suction port 21 of the ozone scrubber 2.

[0034] Inside the scrubber case 20, the air passes through the ozone adsorbent 8 in the direction of airflow A1, causing ozone in the intake air to be adsorbed onto the ozone adsorbent 8.

[0035] The inhaled air, from which ozone has been removed, flows from the pump connection port 22 of the ozone scrubber 2 through the suction port 31 of the aldehyde collector 3 into the collection case 30.

[0036] Inside the collection case 30, the aldehyde is adsorbed as the inhaled air passes through the aldehyde adsorbent 38 in the direction of atmospheric flow A2.

[0037] The collected aldehydes are derivatized with DNPH. DNPH is desorbed using an organic solvent such as acetonitrile, and this desorbed solution is analyzed using analytical instruments such as HPLC. The analytical results are displayed as a chromatogram by processing the electrical output signal of the analytical instrument.

[0038] Figure 2(b) is a chromatogram obtained by operating the aldehyde collection device 1 according to the present invention shown in Figure 1 under the same conditions (environment) as in the conventional example shown in Figure 2(a), and analyzing the collected aldehyde with the same detector as in Figure 2(a). In other words, it is a chromatogram showing the results of sampling performed at a temperature of 40°C using a mist-like sample gas. The horizontal axis shows the retention time (min), and the vertical axis shows the response from the detector, i.e., the electrical signal intensity (mAU).

[0039] In Figure 2(b), a peak P1 for formaldehyde occurs between retention times of 4.5 minutes and 5.0 minutes, and a peak P2 for acetaldehyde occurs between retention times of 6.0 minutes and 6.5 minutes, similar to Figure 2(a). However, a ghost peak P3 like that in Figure 2(a) does not appear.

[0040] In other words, even when sampling is performed under the same high temperature and high humidity conditions as in conventional examples, if 3,3',5,5'-tetramethylbenzidine is used as an ozone remover, deliquescence does not occur, and ghost peaks P3 caused by deliquescence, as shown in Figure 2(a), do not appear. This allows for accurate measurement of aldehydes.

[0041] Furthermore, regarding the formaldehyde peak P1, the peak height (peak area) is maintained higher in this embodiment shown in Figure 2(b) than in the conventional example shown in Figure 2(a). This indicates that the decrease in the formaldehyde peak area is suppressed more efficiently than in the conventional method.

[0042] In Figures 2(a) and 2(b), a large peak P0 preceding the formaldehyde peak P1 appears between retention times of 2.5 and 3.5 minutes. This peak P0 is the peak where DNPH (2,4-dinitrophenylhydrazine), used in the aldehyde adsorbent 38 in the aldehyde collector 3 shown in Figure 1, was detected.

[0043] Thus, according to the ozone scrubber 2 and ozone removal method of this embodiment, even in rainy weather or in atmospheric environments with high humidity, the ozone removal agent 3,3',5,5'-tetramethylbenzidine does not deliquesce or dissolve, thereby preventing clogging of the ozone scrubber 2 and maintaining its ozone removal performance.

[0044] Furthermore, according to the aldehyde collection device 1 and aldehyde collection method of this embodiment, clogging of the ozone scrubber can be prevented, similar to the case of the ozone scrubber 2, and the ozone removal performance can be maintained, while eliminating the effect of eluting ozone removal agents on the aldehyde collector 3, as in the conventional method. In other words, it is possible to reduce the peak area of ​​formaldehyde or suppress the occurrence of ghost peaks.

[0045] [Other embodiments] (1) In Figure 1, the aldehyde collection device 1 directly connects the ozone scrubber 2 and the aldehyde collector 3, but it is also possible to have a structure that connects them indirectly via an atmospheric circulation pipe or the like.

[0046] (2) In the aldehyde collection device 1 shown in Figure 1, the aldehyde collector 3 is connected to the suction pump 6 via the suction hose 5, but it is also possible to connect them directly.

[0047] (3) The ozone scrubber 2 according to the present invention is not limited to the configuration in which it is connected to the aldehyde collector 3 shown in Figure 1, but can also be connected to collectors for other gases and used to measure gases other than aldehydes.

[0048] Each embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications are permitted without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0049] 1. Aldehyde collection device 2 Ozone Scrubber 3. Aldehyde collector 6. Suction pump 8. Ozone adsorbent 38. Aldehyde Adsorbent P1: Peak of formaldehyde P2: Peak of acetaldehyde P3 Ghost Peak

Claims

1. An ozone scrubber in which an ozone adsorbent, consisting of 3,3',5,5'-tetramethylbenzidine supported on a diatomaceous earth carrier, is housed in a scrubber case.

2. The ozone scrubber according to claim 1, wherein the scrubber case is formed of a light-shielding material.

3. An ozone removal method comprising passing an ozone adsorbent, which has 3,3',5,5'-tetramethylbenzidine supported on a diatomaceous earth carrier, through an ozone adsorbent to remove ozone from the atmosphere.

4. The ozone removal method according to claim 3, wherein the ozone adsorbent is shielded from light from the outside by a light-shielding member.

5. A suction pump for drawing in air, and an aldehyde collector connected directly or indirectly to the suction pump, The aldehyde collector comprises an ozone scrubber connected directly or indirectly to the suction port, The ozone scrubber is an aldehyde collection device comprising an ozone adsorbent, which consists of 3,3',5,5'-tetramethylbenzidine supported on a diatomaceous earth carrier, housed in a scrubber case.

6. The aldehyde collection device according to claim 5, wherein the aldehyde collector is filled with DNPH (2,4-dinitrophenylhydrazine) impregnated silica gel in a collection case.

7. The aldehyde collection apparatus according to claim 5 or 6, wherein the scrubber case is formed of a light-shielding material.

8. A process of drawing in air containing ozone, A step of removing ozone from the atmosphere by passing the atmosphere through an ozone adsorbent, which is made by supporting 3,3',5,5'-tetramethylbenzidine on a diatomaceous earth carrier. A method for collecting aldehydes, comprising the step of drawing the air after ozone removal into an aldehyde collector and collecting the aldehydes.

9. The aldehyde collection method according to claim 8, wherein the step of collecting the aldehyde is performed using silica gel impregnated with DNPH (2,4-dinitrophenylhydrazine).

10. The aldehyde collection method according to claim 8 or 9, wherein the ozone adsorbent is shielded from light from the outside in the step of removing the ozone.

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