JP2014237090A - Treating device and treating method of waste gas containing ethylene oxide gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating device and a treating method excellent in the removal performance of ethylene oxide gas contained in a waste gas.SOLUTION: A treating device of a waste gas to remove ethylene oxide gas contained in the waste gas after sterilization treatment is provided with an adsorption cylinder to remove ethylene oxide from the waste gas where activated carbon whose raw material is petroleum or coal is filled and ethylene oxide is removed from the waste gas by adsorbing and decomposing the ethylene oxide gas due to the contact of the waste gas with the activated carbon. Moreover, the activated carbon is preferably spherical.

Description

  The present invention relates to a waste gas treatment apparatus for removing ethylene oxide gas contained in waste gas after sterilization treatment. The present invention also relates to a waste gas treatment method for removing ethylene oxide gas contained in waste gas after sterilization treatment. Furthermore, the present invention relates to a sterilization apparatus for removing ethylene oxide gas contained in waste gas after sterilization.

  An important item related to medical safety assurance is sterilization assurance. With the advancement of medical care, there has been a strong demand for guaranteeing sterilization of medical devices used in medical settings. Examples of the sterilization method include ethylene oxide gas sterilization method (hereinafter may be abbreviated as EOG sterilization method), drug sterilization method, high-pressure steam sterilization method, radiation sterilization method, etc., which are optimal depending on the material of the medical device. Sterilization is adopted. At present, disposable products made of polyethylene, polypropylene, silicone, polyvinyl chloride or the like are widely used as medical devices. The EOG sterilization method is the mainstream among the above sterilization methods because the material is very little damaged, easy to operate, and effective against a wide spectrum of bacteria.

  However, while ethylene oxide gas (hereinafter sometimes abbreviated as EOG) is effective against bacteria and microorganisms, it has no influence on the worker's body. In particular, EOG is feared to cause transient or long-term damage to the skin and mucous membranes (for example, Sesuke Takashima “Experimental Study on the Effect of Ethylene Oxide on the Tracheal Epithelium”, Otolaryngology, Supplement 11) : 1-25, 1987).

  In addition, local governments such as Tokyo, Osaka, and Saitama have enforced extremely strict zero regulations for EOG discharged into the atmosphere at medical facilities and medical device manufacturing facilities. It is inevitable that the regulations will be expanded.

  In large-scale medical facilities in Japan, EOG is decomposed by some method. A typical method for decomposing EOG includes a catalytic decomposition method in which EOG is decomposed into carbon dioxide gas and water. The most common catalytic cracking method is to fill a solid reactor such as vanadium pentoxide into a cylindrical reactor with both ends opened, made of metal or ceramic, and introduce EOG into the reactor. It is the method of heating to 250-350 degreeC. In the catalytic cracking method, it is known that the catalyst activity decreases with time, and it is necessary to replace the catalyst appropriately. However, since the catalyst used in the catalytic cracking method is expensive, it is practically difficult to replace it frequently.

  On the other hand, the present inventors have studied a decomposition method in which EOG is hydrolyzed to ethylene glycol (hereinafter sometimes abbreviated as EG) using sulfuric acid. EOG is a gas having a boiling point of 12.5 ° C., and its explosion limit is extremely wide from an extremely low concentration (0.1%) to almost 100%, and if there is a fire source, the risk of explosion is extremely high. When handling EOG, it is necessary to pay close attention to ignition and explosion, but the hydrolysis method using sulfuric acid is safe because it can be operated at normal temperature and pressure. Although the hydrolysis method depends on the volume of the sulfuric acid aqueous solution used, it has been confirmed that when the treatment is performed for a certain period of time, the pH of the sulfuric acid aqueous solution increases and the decomposition rate of EOG decreases. Therefore, the sulfuric acid aqueous solution that has been treated for a certain period of time needs to be replaced, and there is a problem that a large amount of the sulfuric acid aqueous solution has to be discarded every time it is replaced.

The method described in Patent Document 1 is a method of treating exhaust gas containing EOG discharged from an EOG sterilizer with a solid acid having a pore diameter of 0.5 to 1.0 nm and a surface area of 80 to 100 m ² / g. Patent Document 1 also describes that the solid acid adsorption / removal activity can be dramatically extended by passing the exhaust gas containing EOG through the water of a dilute sulfuric acid aqueous solution before it is treated with the solid acid. Has been. In addition, in the Example of patent document 1, the processing method using the zeolite 13X (pore diameter: 0.9 nm) as a solid acid is described, and the processing method using coconut shell activated carbon is described in the comparative example. Yes. However, the solid acid described in Patent Document 1 has insufficient EOG removal performance and has been required to be improved.

JP 2008-114210 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a processing apparatus and a processing method excellent in the performance of removing EOG contained in waste gas.

  The above-mentioned problem is a waste gas treatment apparatus that removes EOG contained in waste gas after sterilization treatment, and is filled with activated carbon made from petroleum or coal, and adsorbs EOG by bringing the waste gas into contact with the activated carbon. This is solved by providing a waste gas treatment apparatus comprising an adsorption cylinder for removing ethylene oxide from the waste gas by decomposition.

  At this time, the activated carbon is preferably spherical.

  The waste gas treatment apparatus preferably includes a dilute sulfuric acid bath or a catalytic cracking tank for further decomposing EOG at the front stage and / or the rear stage of the adsorption cylinder. Moreover, it is preferable that the said waste gas processing apparatus is equipped with the monitoring means which monitors the density | concentration of EOG contained in this waste gas in the waste gas exit of the said adsorption cylinder. At this time, the monitoring means is preferably a dye that reacts with EOG.

  The above-mentioned problem is a waste gas treatment method for removing EOG contained in waste gas after sterilization treatment, by contacting the waste gas with activated carbon made of petroleum or coal as a raw material, and adsorbing and decomposing EOG. It is also solved by providing a waste gas treatment method characterized by removing ethylene oxide from the waste gas.

  The above-described problem is a sterilization apparatus for sterilizing a medical device using EOG, a container for storing the medical device, means for supplying a gas containing ethylene oxide to the container, and petroleum or coal as a raw material. And an adsorption cylinder for removing ethylene oxide from the waste gas by bringing ethylene oxide contained in the waste gas discharged from the container into contact with the activated carbon to adsorb and decompose EOG. The problem can also be solved by providing a sterilization apparatus characterized by comprising the above.

  According to the present invention, it is possible to provide a processing apparatus and a processing method excellent in the removal efficiency of EOG contained in waste gas.

It is a figure which shows the processing apparatus 1 which concerns on the embodiment of this invention. It is a figure which shows the experimental apparatus 2 used in the Example. In Example 1 and Comparative Examples 1-2, it is the graph which made the elapsed time (min) after starting a processing test the horizontal axis, and made the EOG adsorption rate (%) calculated | required by Formula (2) the vertical axis | shaft. In Comparative Examples 3-6, it is the graph which made the elapsed time (min) after starting a processing test the horizontal axis, and made EOG adsorption | suction rate (%) calculated | required by Formula (2) on the vertical axis | shaft.

  The present invention is a waste gas treatment apparatus that removes EOG contained in waste gas after sterilization, and is filled with activated carbon made from petroleum or coal, and adsorbs EOG by bringing the waste gas into contact with the activated carbon. The waste gas treatment apparatus includes an adsorption cylinder for removing EOG from the waste gas by being decomposed. The greatest feature of the present invention is that the activated carbon filled in the adsorption cylinder is activated carbon made from petroleum or coal. So far, the present inventors have studied a method for removing ethylene oxide in waste gas using activated carbon made of zeolite or plants as raw material, but its adsorption performance has not always been sufficient. As a result of intensive studies by the present inventors, it has been surprisingly found that the removal performance of EOG is greatly improved by using activated carbon made from petroleum or coal.

  In addition, the present inventors have predicted that the adsorption mode of EOG on activated carbon will be physical adsorption from past knowledge. However, as a result of extracting the activated carbon after contacting EOG with acetone and analyzing the components contained in the acetone, most of the components were EG. It became clear for the first time by the present inventors that EOG is decomposed into EG by bringing EOG into contact with activated carbon made from petroleum or coal.

  In the present invention, activated carbon using petroleum or coal as a raw material is manufactured using materials derived from minerals such as peat, lignite, lignite, bituminous coal, anthracite, coke, coal tar, coal pitch, petroleum distillation residue, petroleum pitch and the like. It is activated carbon. Such activated carbon using petroleum or coal as a raw material has remarkably superior EOG adsorption performance compared to activated carbon derived from plants.

  Activated carbon is generally classified into powdered activated carbon, granular activated carbon, and fibrous activated carbon based on its shape. Further, granular activated carbon is classified into crushed charcoal and spherical or cylindrical shaped charcoal. In order to efficiently remove EOG from waste gas, the activated carbon is preferably spherical.

  The manufacturing method of the activated carbon used by this invention is not specifically limited. A suitable production method for producing spherical activated carbon includes a method of kneading and granulating using a mineral-derived material to form a desired particle size and shape, and then performing carbonization treatment and activation treatment. It is done. When producing spherical activated carbon in this way, a binder is required at the time of molding by using raw materials having fluidity such as coal tar, coal pitch, petroleum distillation residue, petroleum pitch among the above-mentioned raw materials. High performance spherical activated carbon can be obtained.

  The activated carbon used in the present invention preferably has an average particle diameter (number average sphere equivalent average diameter) of 10 mm or less, more preferably 5 mm or less, and even more preferably 1 mm or less. On the other hand, for convenience of handling, the average particle size is 0.1 mm or more.

In the present invention, the larger the specific surface area per unit weight of the activated carbon, the better the contact efficiency with the waste gas. The BET specific surface area of the activated carbon in the present invention is preferably 100 m ² / g or more, and more preferably 500 m ² / g or more. On the other hand, the BET specific surface area is usually 10000 m ² / g or less.

  Hereinafter, the processing apparatus 1 which concerns on the embodiment of this invention is demonstrated, referring drawings. This embodiment is merely a specific example, and does not limit the technical scope of the present invention.

  As shown in FIG. 1, the processing apparatus 1 includes a sterilizer 10, an adsorption cylinder 20, and a dilute sulfuric acid bath 30. The waste gas treatment apparatus of the present invention only needs to have at least the adsorption cylinder 20, and the sterilizer 10 and the dilute sulfuric acid bath 30 have arbitrary configurations.

  The sterilizer 10 is a highly airtight container in which an object to be processed such as a medical tool is placed. Then, a gas containing EOG (hereinafter sometimes simply referred to as gas) is introduced into the sterilizer 10 from the gas inlet 11. Next, the gas inlet 11 is closed and sterilization is performed in the sterilizer 10 for a predetermined time. At this time, the gas introduced into the sterilizer 10 may be only EOG or may contain other gas. As other gas, carbon dioxide gas, nitrogen gas, water vapor and the like can be used. From the viewpoint of sterilization efficiency, it is preferable to use a gas in which 10% by weight or more is EOG. Further, when introducing the gas into the sterilizer 10, it is preferable to depressurize the sterilizer 10 in advance by a decompression pump (not shown) or the like. After the sterilization process, the gas in the sterilizer 10 is discharged from the gas outlet 12 as waste gas and introduced into the adsorption cylinder 20. When exhausting the waste gas, it is preferable that the exhaust gas is evacuated by a decompression pump (not shown). Moreover, it is also preferable to repeat purging air in the sterilizer 10 and exhausting under reduced pressure thereafter. At that time, waste gas discharged after purging can also be introduced into the adsorption cylinder 20 as necessary.

  The adsorption cylinder 20 is filled with activated carbon made from petroleum or coal. The filling amount of the activated carbon in the adsorption cylinder 20 is appropriately set in consideration of the EOG adsorption rate, the introduced waste gas amount, the pressure loss during ventilation, and the like. The material of the adsorption cylinder 20 is not particularly limited as long as it does not deteriorate or corrode due to gas, and representative examples thereof include metal, glass, and plastic. The length and inner diameter of the adsorption cylinder 20 are not particularly limited, but are set as appropriate in consideration of the EOG adsorption rate, the amount of introduced waste gas, the pressure loss during ventilation, and the like.

  Moreover, it is preferable to provide a monitoring means for monitoring the EOG concentration in the adsorption cylinder 20 at the outlet of the adsorption cylinder 20. The monitoring means is preferably a dye that reacts with EOG from the viewpoint of simplicity. A sheet impregnated with an aqueous dye solution is installed at the outlet in the adsorption cylinder 20, and the EOG concentration in the adsorption cylinder 20 can be monitored by observing a change in the color of the sheet from the peeping glass 21. The dye is not particularly limited as long as it changes color by reacting with EOG at a specific EOG concentration, and examples thereof include alizarin red.

  Although FIG. 1 shows an example in which four adsorption cylinders 20 are installed in parallel, the number and the installation method of the adsorption cylinders 20 are not limited, and a plurality of adsorption cylinders 20 may be installed in series. The adsorption cylinder 20 is preferably a cartridge type that can be removed from the processing apparatus 1. For example, if a plurality of adsorption cylinders 20 are installed in parallel, the adsorption cylinders 20 can be exchanged while operating the processing apparatus 1 by valve operation. The removed adsorption cylinder 20 may be discarded as it is, or the activated carbon may be refilled and attached to the processing apparatus 1 again. When the adsorption cylinder 20 is formed of a plastic container that can be incinerated, the entire adsorption cylinder 20 can be incinerated, and EOG leakage to the work environment can be minimized. Even when the suction cylinder 20 is reused, most of the sucked EOG is converted to EG, so that leakage to the working environment during handling is greatly suppressed. In any case, the activated carbon after use can be easily incinerated. At that time, almost no incineration residue or harmful gas is generated. Is also excellent.

  Waste gas discharged from the adsorption cylinder 20 is introduced into the dilute sulfuric acid bath 30 through the gas inlet 31 and passes through the 10 wt% sulfuric acid aqueous solution 32 in the dilute sulfuric acid bath 30. As a result, EOG remaining in the waste gas is hydrolyzed into EG. Although not shown, the sulfuric acid bath 30 may be equipped with a pH meter for measuring the pH of the 10 wt% sulfuric acid aqueous solution 32.

  Moreover, it is preferable that the processing apparatus 1 is provided with the catalytic cracking tank filled with the solid catalyst which decomposes | disassembles EOG instead of the dilute sulfuric acid bath 30. FIG. The solid catalyst is not particularly limited as long as it can decompose and detoxify EOG, but vanadium pentoxide is typical.

  As described above, the waste gas discharged from the sterilizer 10 is processed by the adsorption cylinder 20 and the dilute sulfuric acid bath 30 and discharged from the gas discharge port 33 to the atmosphere.

  Conventionally, the catalytic cracking method and the hydrolysis method as described above have been used for the treatment of EOG. In the hydrolysis method, although it depends on the volume of the sulfuric acid aqueous solution to be used, it has been confirmed that when the treatment is performed for a certain period of time, the pH of the sulfuric acid aqueous solution increases and the decomposition rate of EOG also decreases.

  The inventors put a 10% by weight sulfuric acid aqueous solution into a reaction vessel (500 mL), and blown a mixed gas containing 20% by weight of EOG and 80% by weight of carbon dioxide into the aqueous sulfuric acid solution at a constant rate. And the change of pH value of sulfuric acid aqueous solution was analyzed. As a result, the pH value of the aqueous sulfuric acid solution was 0 within a fixed time after the start of the reaction, and when the gas that passed through the aqueous sulfuric acid solution was analyzed by gas chromatography, the EOG decomposition rate was 100%. However, when the test was continued for 2 weeks, the pH value of the sulfuric acid aqueous solution increased to 1.0, and the EOG degradation rate decreased to 99%. When the experiment was further continued, the pH value further increased to 2.0, and the EOG decomposition rate further decreased to 98%.

  In such a hydrolysis method, if the EOG concentration of the gas blown into the sulfuric acid aqueous solution is lowered in advance, the pH value of the sulfuric acid aqueous solution is kept low over a long period of time, and the EOG concentration released from the reaction tank to the atmosphere. Can be maintained at a low value. Therefore, by providing an adsorption cylinder filled with activated carbon made of petroleum or coal as a raw material, it is possible to significantly suppress the pH increase of the sulfuric acid aqueous solution.

  On the other hand, it is known that the catalytic activity of the catalytic cracking method decreases when the operation is continued for a long time. In addition, in order to decompose at a high temperature, it is necessary to pay attention to the corrosion of the metal member due to the high concentration EOG coming into contact with the high temperature portion in the apparatus. Therefore, by providing an adsorption cylinder filled with activated carbon made from petroleum or coal, it is possible to greatly extend the life of the catalyst, as well as to suppress the corrosion of piping, as in the hydrolysis method. Become possible

  As described above, it is preferable to further include a dilute sulfuric acid bath or a catalytic cracking tank for decomposing EOG at the subsequent stage of the adsorption cylinder, which is useful for extending the life of the catalyst and dilute sulfuric acid bath.

  In addition, in the case where a dilute sulfuric acid bath or catalytic cracking tank for further decomposing EOG is provided in the previous stage of the adsorption cylinder, EOG that could not be completely decomposed in the dilute sulfuric acid bath or the catalytic cracking tank due to malfunction of the apparatus is released into the atmosphere Can be prevented. For waste gas with low EOG concentration discharged after purging air into the sterilizer, an adsorption cylinder filled with activated carbon made from petroleum or coal without going through a dilute sulfuric acid bath or catalytic cracking tank It is also possible to release air into the atmosphere only through.

  The waste gas treatment apparatus of the present invention can effectively remove EOG contained in waste gas after sterilization by making use of excellent EOG removal performance. Among them, a sterilization apparatus including a container for storing a medical device, means for supplying a gas containing ethylene oxide to the container, and the adsorption cylinder is a preferred embodiment.

Example 1
Using the experimental apparatus 2 shown in FIG. 2, the EOG treatment was performed according to the following procedure.

(1) A glass tube 50 having an inner diameter of 10 mm and a length of 30 cm was prepared. The glass tube was filled with spherical activated carbon “A-BAC SP” (average particle diameter: 0.40 mm or less, BET specific surface area: 1100 to 1300 m ² / g) manufactured by Kureha Corporation and made from petroleum pitch as a raw material. According to the particle size distribution curve by sieving, the particle size of almost all particles falls within the range of 0.2 to 0.45 mm.
(2) The filter paper impregnated with alizarin red was allowed to stand at the glass tube outlet 90.
(3) A sample gas (composition: EOG 20 wt%, CO ₂ : 80 wt%) was filled in a 20 L Mylar bag 40.
(4) 1.0 mL of sample gas before being introduced into the glass tube 50 was sampled from a sample gas sampling port (inlet) 70 using a gas tight syringe.
(5) The sample gas filled in the Mylar bag 40 was introduced into the glass tube 50 at a flow rate of 50 mL / min using the pump 60.
(6) 1.0 mL of sample gas was sampled from the sample gas sampling port (exit) 80 every predetermined time using a gas tight syringe.
(7) The sample gas before the treatment collected in the procedure (4) and the sample gas after the treatment collected in the procedure (6) were analyzed by gas chromatography.

The gas chromatographic analysis was performed using the following apparatus.
・ Device: GC-2014 type, manufactured by Shimadzu Corporation ・ Detector: FID
Column: PORAPAK QS, 50-80 mesh
3mmφ x 2m (gas column)
-Temperature: Sample inlet 250 ° C, detector 140 ° C, column 250 ° C
Carrier gas: Nitrogen _PN2 200 MPa
-Combustion gas: Hydrogen P _H2 100 MPa
・ Air P _Air : 50 MPa
・ Gas amount for GC analysis: 1mL

  And from the result of the gas chromatography analysis, the EOG adsorption rate (%) of the activated carbon filled in the glass tube 50 was calculated based on the following formulas (1) and (2).

EOG residual rate (%) = (peak area derived from EOG (after treatment)) / (peak area derived from EOG (before treatment)) × 100 (1)
EOG adsorption rate (%) = 100-EOG residual rate (%) (2)

  FIG. 3 is a graph in which the horizontal axis represents the elapsed time (min) from the start of processing, and the vertical axis represents the EOG adsorption rate (%) obtained by the above equation (2). Each point shown in FIG. 3 is a point where the procedure (6) is performed. As shown in FIG. 3, it was found that most of the EOG contained in the sample gas was adsorbed on the activated carbon until approximately 2250 min after the start of the treatment. As shown in FIG. 3, EOG was hardly adsorbed in about 2550 minutes after the start of the treatment. The same experiment was conducted with the weight of activated carbon filled in the glass tube halved (5 g), but the time to reach the saturated adsorption rate was also halved.

  Further, the activated carbon filled in the glass tube 50 was taken out, extracted with acetone, the acetone was removed by evaporation, and the evaporation residue was dissolved again in a small amount of acetone for gas chromatography analysis. As a result, it was found that most of the components contained in acetone were EG. From this, it was found that EOG was chemisorbed on activated carbon and decomposed into EG.

  Furthermore, the color of the filter paper impregnated with alizarin red installed at the glass tube outlet 90 changed from red to yellow when the EOG adsorption rate (%) reached 40%.

Comparative Example 1
Instead of spherical activated carbon, Kuraray Chemical Co., Ltd. coconut shell powder activated carbon “GW 10/32” (specific surface area: 1000 m ² / g: particle size of about 2 mm) was filled in glass tube 50 instead of spherical activated carbon. The same treatment as in Example 1 was performed. The results are shown in FIG. It can be seen that the EOG adsorption rate is reduced in a short time of about 1/5 compared to Example 1.

Comparative Example 2
Eggplant shell activated carbon “GW 10/32” (specific surface area: 1000 m ² / g) manufactured by Kuraray Chemical Co., Ltd. was ground in a mortar. And the process similar to Example 1 was performed except having filled the glass tube 50 with the ground activated carbon (particle diameter of 1 mm or less) instead of the spherical activated carbon. The results are shown in FIG. It can be seen that the EOG adsorption rate is reduced in a shorter time than Comparative Example 1.

Comparative Example 3
Zeolite "Zeoram F-9" manufactured by Tosoh Corporation instead of spherical activated carbon (synthetic zeolite made of crystalline aluminosilicate of alkali metal or alkaline earth metal, spherical 4-8 mesh (2.4-4.7 mm) )) Was performed in the same manner as in Example 1 except that the glass tube 50 was filled. The results are shown in FIG. It can be seen that almost no EOG is adsorbed from the start of the test.

Comparative Example 4
A treatment similar to that in Example 1 was performed except that a zeolite “Zeoram F-9” manufactured by Tosoh Corporation instead of the spherical activated carbon was washed with an aqueous hydrochloric acid solution and dried, and the glass tube 50 was filled. The results are shown in FIG. It is considered that alkali metal ions or alkaline earth metal ions in the zeolite were removed by washing the zeolite with an acid, so that it functioned as a solid acid. Compared to Example 1, the initial EOG adsorption rate It can be seen that the EOG adsorption rate decreases in a short time of about 1/10.

Comparative Example 5
Example except that glass tube 50 was filled with cation exchange resin “DOWEX 50W × 8” (strong acid cation exchange resin (H form), 200-400 mesh) manufactured by Dow Chemical Co., Ltd. instead of spherical activated carbon. 1 was performed. The results are shown in FIG. Compared with Example 1, it can be seen that the initial EOG adsorption rate is low.

Comparative Example 6
The same treatment as in Example 1 was performed except that glass tube 50 was filled with γ-alumina (γ-Al ₂ O ₃ ) manufactured by STREM CHEMICALS instead of spherical activated carbon. The results are shown in FIG. It can be seen that almost no EOG is adsorbed from the start of the test.

DESCRIPTION OF SYMBOLS 1 Processing apparatus 10 Sterilizer 11 Gas inlet 12 Gas discharge path 20 Adsorption cylinder 21 Peeping glass 30 Dilute sulfuric acid bath 31 Gas inlet 32 10 wt% sulfuric acid aqueous solution 33 Gas outlet 2 Experimental apparatus 40 Mylar bag 50 Glass tube 60 Pump 70 Sample gas sampling port (inlet)
80 Sample gas sampling port (exit)
90 Glass tube outlet

Claims (7)

  A waste gas treatment device that removes ethylene oxide gas contained in waste gas after sterilization treatment, filled with activated carbon made from petroleum or coal, and adsorbs ethylene oxide gas by contacting the waste gas with the activated carbon A waste gas treatment apparatus comprising an adsorption cylinder for removing ethylene oxide from the waste gas by being decomposed.   The waste gas treatment apparatus according to claim 1, wherein the activated carbon is spherical.   The waste gas treatment apparatus according to claim 1 or 2, further comprising a dilute sulfuric acid bath or a catalytic cracking tank for decomposing ethylene oxide gas at a front stage and / or a rear stage of the adsorption cylinder.   The waste gas processing apparatus according to any one of claims 1 to 3, further comprising a monitoring unit that monitors the concentration of ethylene oxide gas contained in the waste gas at a waste gas outlet of the adsorption cylinder.   The waste gas treatment apparatus according to claim 4, wherein the monitoring means is a pigment that reacts with ethylene oxide gas.   A waste gas treatment method for removing ethylene oxide gas contained in waste gas after sterilization, wherein the waste gas is brought into contact with activated carbon made from petroleum or coal to adsorb and decompose ethylene oxide gas. A method for treating waste gas, comprising removing ethylene oxide from the waste gas. A sterilization apparatus for sterilizing medical devices using ethylene oxide gas,
A container for storing medical devices;
Means for supplying a gas containing ethylene oxide to the container;
Activated carbon made from petroleum or coal is filled, and ethylene oxide contained in the waste gas discharged from the container is brought into contact with the activated carbon to adsorb and decompose the ethylene oxide gas to thereby remove ethylene oxide from the waste gas. A sterilization apparatus comprising an adsorption cylinder for removal.

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