Gas processing method and gas processing device

Abstract

Provided are a gas treatment method by which bromofluoroethylene can be efficiently removed and a gas treatment device. According to the present invention, bromofluoroethylene is separated from a bromofluoroethylene-containing gas by bringing the gas into contact with an adsorbent (7), which has pores with an average pore size of 0.4-4 nm inclusive, in a temperature environment of 0°C or higher and lower than 120°C and thus allowing the adsorbent (7) to adsorb bromofluoroethylene.

Description

[Technical field]

[0001] The present invention relates to a gas processing method and a gas processing device. [Background technology]

[0002] In the semiconductor manufacturing process, perfluorocarbons such as carbon tetrafluoride and ethane hexafluoride are used as etching gases in dry etching equipment and chamber cleaning gases in CVD equipment. These perfluorocarbons are very stable compounds and have a large impact on global warming, so there are concerns about the adverse effects on the environment when they are released into the atmosphere. Therefore, it is preferable to release the exhaust gas discharged from the semiconductor manufacturing process into the atmosphere after recovering or decomposing the perfluorocarbons contained therein.

[0003] Patent Document 1 discloses a plasma etching gas containing bromofluorocarbon (bromofluoroalkene) having a double bond as an alternative to the above-mentioned perfluorocarbon and having a small environmental load. Bromofluoroalkene has a smaller impact on global warming than perfluorocarbons without double bonds such as carbon tetrafluoride and ethane hexafluoride, but the impact is not so small that it can be ignored. In addition, bromofluoroalkene is highly toxic and will have a negative impact on the human body and the environment if released directly into the atmosphere, so the exhaust gas discharged from the semiconductor manufacturing process must be released into the atmosphere after the bromofluoroalkene contained therein is recovered or decomposed. As a method for treating bromofluoroalkene, for example, Patent Document 2 proposes a method in which a bromofluoroalkene having 3 or 4 carbon atoms is adsorbed on a zeolite. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 124726 [Patent Document 2] Japan Patent Publication No. 47338, 2017 Summary of the Invention [Problem to be solved by the invention]

[0005] However, a method for efficiently removing bromofluoroalkene having two carbon atoms (bromofluoroethylene) has not yet been found. An object of the present invention is to provide a gas treatment method and a gas treatment apparatus capable of efficiently removing bromofluoroethylene. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present invention is as follows [1] to [9]. [1] A gas treatment method for separating bromofluoroethylene from a gas containing bromofluoroethylene by contacting the gas with an adsorbent having pores with an average pore size of 0.4 nm or more and 4 nm or less in a temperature environment of 0°C or more and less than 120°C, and adsorbing the bromofluoroethylene onto the adsorbent.

[0007] [2] The gas processing method according to [1], wherein the bromofluoroethylene is at least one of bromotrifluoroethylene, 1-bromo-2,2-difluoroethylene, (E)-1-bromo-1,2-difluoroethylene, (Z)-1-bromo-1,2-difluoroethylene, 1-bromo-1-fluoroethylene, (E)-1-bromo-2-fluoroethylene, (Z)-1-bromo-2-fluoroethylene, 1,1-dibromo-2-fluoroethylene, (E)-1,2-dibromo-2-fluoroethylene, (Z)-1,2-dibromo-2-fluoroethylene, and tribromofluoroethylene.

[0008] [3] The gas treatment method according to [1] or [2], wherein the gas containing bromofluoroethylene is a mixed gas of the bromofluoroethylene and an inert gas. [4] The gas processing method according to [3], wherein the inert gas is at least one of nitrogen gas, helium, argon, neon, and krypton. [5] The gas treatment method according to any one of [1] to [4], wherein the content of the bromofluoroethylene in the gas containing the bromofluoroethylene is less than 25 volume %.

[0009] [6] The gas treatment method according to any one of [1] to [5], wherein the adsorbent is at least one of zeolite and activated carbon. [7] The gas processing method according to any one of [1] to [6], wherein the temperature environment is 0°C or higher and 100°C or lower. [8] The gas processing method according to any one of [1] to [6], wherein the temperature environment is 0°C or higher and 70°C or lower.

[0010] [9] An adsorption treatment vessel containing an adsorbent having pores with an average pore diameter of 0.4 nm to 4 nm; The adsorption treatment container has a supply port through which a gas containing bromofluoroethylene is supplied, and a discharge port through which treated gas obtained by subjecting the gas containing bromofluoroethylene to adsorption treatment with the adsorbent is discharged from within the adsorption treatment container to the outside. Effect of the Invention

[0011] According to the present invention, bromofluoroethylene can be efficiently removed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram illustrating a configuration of a gas treatment device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of the present invention will be described below. Note that this embodiment is merely an example of the present invention, and the present invention is not limited to this embodiment. In addition, various modifications and improvements can be made to this embodiment, and such modifications and improvements can also be included in the present invention.

[0014] The gas treatment device 1 of this embodiment includes an adsorption tower 6 (corresponding to an "adsorption treatment container" which is a constituent element of the present invention) containing an adsorbent 7 having pores with an average pore diameter of 0.4 nm or more and 4 nm or less. The adsorption tower 6 has a supply port 4 through which a gas containing bromofluoroethylene is supplied, and an exhaust port 5 through which a treated gas obtained by subjecting the gas containing bromofluoroethylene to an adsorption treatment with the adsorbent 7 is exhausted from the adsorption tower 6 to the outside.

[0015] Furthermore, the gas processing device 1 of this embodiment includes a bromofluoroethylene gas supply mechanism 2 that supplies bromofluoroethylene gas, an inert gas supply mechanism 3 that supplies an inert gas, and a Fourier transform infrared spectrophotometer 8 that performs Fourier transform infrared spectroscopic analysis. The bromofluoroethylene gas supply mechanism 2 and the supply port 4 of the adsorption tower 6 are connected by piping, and the bromofluoroethylene gas sent from the bromofluoroethylene gas supply mechanism 2 is supplied from the supply port 4 to the inside of the adsorption tower 6, where it is subjected to adsorption treatment by the adsorbent 7 in a temperature environment of not less than 0°C and not more than 120°C.

[0016] The gas supplied from the supply port 4 to the inside of the adsorption tower 6 may be bromofluoroethylene gas consisting of only bromofluoroethylene, or may be a mixed gas of bromofluoroethylene gas and other gases. The other gases are not particularly limited, but may be, for example, inert gas. That is, as shown in FIG. 1, a pipe extending from a bromofluoroethylene gas supply mechanism 2 and a pipe extending from an inert gas supply mechanism 3 may be joined together, and the joined pipe may be connected to the supply port 4 of the adsorption tower 6.

[0017] With this configuration, the bromofluoroethylene gas delivered from the bromofluoroethylene gas supply mechanism 2 and the inert gas delivered from the inert gas supply mechanism 3 are mixed in the joined piping to form a mixed gas, and the mixed gas is supplied from the supply port 4 to the inside of the adsorption tower 6. Hereinafter, bromofluoroethylene gas consisting only of bromofluoroethylene, and a mixed gas of bromofluoroethylene gas and other gases may also be referred to as a "bromofluoroethylene-containing gas."

[0018] The bromofluoroethylene-containing gas supplied to the inside of the adsorption tower 6 comes into contact with the adsorbent 7 in a temperature environment of 0° C. or higher and lower than 120° C., and is subjected to an adsorption treatment by the adsorbent 7. That is, since the bromofluoroethylene in the bromofluoroethylene-containing gas is adsorbed by the adsorbent 7, the bromofluoroethylene-containing gas is separated into bromofluoroethylene and other types of gases. The treated gas obtained by the adsorption treatment with the adsorbent 7, i.e., the separated other gases, is discharged from the adsorption tower 6 to the outside through the exhaust port 5. The exhaust port 5 and the Fourier transform infrared spectrophotometer 8 are connected by piping, so that the treated gas is supplied to the Fourier transform infrared spectrophotometer 8.

[0019] In the Fourier transform infrared spectrophotometer 8, Fourier transform infrared spectroscopic analysis of the treated gas is carried out, and quantitative or qualitative analysis of the bromofluoroethylene contained in the treated gas is carried out. A waste pipe 9 is connected to the Fourier transform infrared spectrophotometer 8, and the treated gas after Fourier transform infrared spectroscopic analysis is discharged to the outside of the system via the waste pipe 9. By using the gas treatment device 1 of this embodiment, bromofluoroethylene can be efficiently removed under mild conditions without the need for complicated operations.

[0020] The gas processing apparatus 1 of this embodiment and the gas processing method of this embodiment will be described in further detail below. [Bromofluoroethylene] Bromofluoroethylene refers to an unsaturated hydrocarbon with two carbon atoms that contains a fluorine atom and a bromine atom in the molecule. Specific examples of bromofluoroethylene include bromotrifluoroethylene, 1-bromo-2,2-difluoroethylene, (E)-1-bromo-1,2-difluoroethylene, (Z)-1-bromo-1,2-difluoroethylene, 1-bromo-1-fluoroethylene, (E)-1-bromo-2-fluoroethylene, (Z)-1-bromo-2-fluoroethylene, 1,1-dibromo-2-fluoroethylene, (E)-1,2-dibromo-2-fluoroethylene, (Z)-1,2-dibromo-2-fluoroethylene, tribromofluoroethylene, and the like.

[0021] Among these, from the viewpoint of easy vaporization at room temperature, bromotrifluoroethylene, 1-bromo-2,2-difluoroethylene, (E)-1-bromo-1,2-difluoroethylene, (Z)-1-bromo-1,2-difluoroethylene, 1-bromo-1-fluoroethylene, (E)-1-bromo-2-fluoroethylene, and (Z)-1-bromo-2-fluoroethylene are preferred. The bromofluoroethylenes may be used alone or in combination of two or more.

[0022] [Inert gas] Examples of the inert gas include nitrogen gas (N2), helium (He), argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe). Among these, nitrogen gas, helium, argon, neon, and krypton are preferred, and nitrogen gas and argon are more preferred. These inert gases may be used alone or in combination of two or more.

[0023] [Adsorbent] The type of adsorbent is not particularly limited as long as it has pores with an average pore diameter of 0.4 nm or more and 4 nm or less. From the viewpoints of economy and availability, however, activated carbon, zeolite, silica gel, and alumina are preferred, and zeolite and activated carbon are more preferred. Examples of the structure of zeolite include T type, erionite type, chabazite type, 4A type, 5A type, ZSM-5 type, LiLSX type, AlPO4-11 type, ferrierite type, offretite type, mordenite type, beta type, AlPO4-5 type, NaY type, NaX type, CaX type, AlPO4-8 type, UTD-1 type, VPI-5 type, cloverite type, MCM-41 type, and FSM-16 type. Among zeolites, from the viewpoint of easy availability, molecular sieve 4A (e.g., manufactured by Union Showa Co., Ltd.), molecular sieve 5A (e.g., manufactured by Union Showa Co., Ltd.), molecular sieve 13X (e.g., manufactured by Union Showa Co., Ltd.), and the like are particularly preferred. When the average pore size of the pores in the adsorbent is 0.4 nm or more and 4 nm or less, bromofluoroethylene is efficiently adsorbed and desorption of the adsorbed bromofluoroethylene is unlikely to occur. The shape of the adsorbent is not particularly limited, and may be, for example, fibrous, honeycomb, cylindrical, pellet, crushed, granular, or powdery.

[0024] [Adsorption treatment temperature] The adsorption process using the adsorbent 7 must be carried out in a temperature environment of 0°C or higher and lower than 120°C, preferably in a temperature environment of 0°C or higher and 100°C or lower, and more preferably in a temperature environment of 0°C or higher and 70°C or lower. If the adsorption treatment is carried out by contacting the bromofluoroethylene-containing gas with the adsorbent 7 under the above temperature environment, the adsorbed bromofluoroethylene is less likely to be desorbed from the adsorbent 7, so that the amount of bromofluoroethylene adsorbed increases. In addition, since no large-scale device for temperature control is required, the configuration of the gas treatment device 1 can be simplified. Furthermore, liquefaction of bromofluoroethylene is less likely to occur in the adsorption tower 6.

[0025] [Other adsorption conditions] Adsorption conditions such as the content (concentration) of bromofluoroethylene in the bromofluoroethylene-containing gas, the flow rate of the bromofluoroethylene-containing gas, the amount of the adsorbent 7, and the size of the adsorption tower 6 are not particularly limited and can be set appropriately depending on the type and amount of the bromofluoroethylene-containing gas. However, the content (concentration) of bromofluoroethylene in the bromofluoroethylene-containing gas can be 50% by volume or less, preferably 30% by volume or less, and more preferably 25% by volume or less. EXAMPLES

[0026] The present invention will be described in more detail below with reference to examples and comparative examples. Example 1 Adsorption treatment of a bromofluoroethylene-containing gas was carried out using a gas treatment device having a configuration similar to that of the gas treatment device 1 shown in Fig. 1. This gas treatment device was equipped with a stainless steel adsorption tower having an inner diameter of 1 inch and a length of 100 mm, and this adsorption tower was filled with 28.7 g of molecular sieve 13X (manufactured by Union Showa Co., Ltd.) as an adsorbent.

[0027] The average pore diameter of the pores of the molecular sieve 13X is 1.0 nm. The average pore diameter was measured by the BET adsorption method under the following measurement conditions. Measuring equipment: BELSORP-max manufactured by Nikkiso Co., Ltd. Adsorbate: Nitrogen gas Measurement temperature: -196℃ Pretreatment of the adsorbent: Heat-dried at 300℃ for 6 hours under vacuum conditions. Amount of adsorbent used: 0.10g

[0028] A mixed gas of bromotrifluoroethylene and dry nitrogen (the content of bromotrifluoroethylene in the mixed gas was 20% by volume) was supplied to the adsorption tower at a flow rate of 50 mL / min to perform the adsorption treatment. During the adsorption treatment, the temperature inside the adsorption tower (specifically, the surface temperature of the adsorbent) was maintained at 30.0 to 40.0°C.

[0029] The concentration of bromotrifluoroethylene in the treated gas discharged from the exhaust port of the adsorption tower was measured using a Fourier transform infrared spectrophotometer. As a result, the concentration of bromotrifluoroethylene for 30 minutes immediately after the start of the supply of the mixed gas was 206.35 to 273.81 ppm by volume (see Table 1 below). In other words, when molecular sieve 13X was used as the adsorbent, 99.86 to 99.90% of the bromotrifluoroethylene was adsorbed by the adsorbent.

[0030] [Table 1]

[0031] Example 2 Bromotrifluoroethylene adsorption treatment was carried out in the same manner as in Example 1, except that coconut shell activated carbon (manufactured by Osaka Gas Chemicals Co., Ltd.) was used as the adsorbent instead of molecular sieve 13X. The average pore size of the pores in the coconut shell activated carbon is 2.5 nm. As a result, the concentration of bromotrifluoroethylene for 30 minutes immediately after the start of the supply of the mixed gas was 27.78 to 436.51 ppm by volume (see Table 2 below). In other words, when coconut shell activated carbon was used as the adsorbent, 99.78 to 99.99% of bromotrifluoroethylene was adsorbed by the adsorbent.

[0032] [Table 2]

[0033] Example 3 Bromotrifluoroethylene adsorption treatment was carried out in the same manner as in Example 1, except that coal-based activated carbon (manufactured by Osaka Gas Chemicals Co., Ltd.) was used as the adsorbent instead of molecular sieve 13X. The average pore size of the pores in the coal-based activated carbon is 3.4 nm. As a result, the concentration of bromotrifluoroethylene for 30 minutes immediately after the start of the supply of the mixed gas was 23.81 to 369.05 ppm by volume (see Table 3 below). In other words, when coal-based activated carbon was used as the adsorbent, 99.82 to 99.99% of bromotrifluoroethylene was adsorbed by the adsorbent.

[0034] [Table 3]

[0035] Example 4 Adsorption treatment of bromotrifluoroethylene was carried out in the same manner as in Example 1, except that Molecular Sieve 5A (manufactured by Union Showa Co., Ltd.) was used as the adsorbent instead of Molecular Sieve 13X. The average pore diameter of the pores in Molecular Sieve 5A was 0.5 nm. As a result, the concentration of bromotrifluoroethylene immediately after the start of the mixed gas supply was 630.95 volume ppm, and the concentration of bromotrifluoroethylene 5 minutes after the start of the mixed gas supply was 5507.94 volume ppm (see Table 4 below). The reason for the decrease in adsorption efficiency is believed to be that the adsorbent broke through. That is, when molecular sieve 5A was used as the adsorbent, although the adsorption capacity was inferior to molecular sieve 13X and the above-mentioned activated carbon, more than 97% of bromotrifluoroethylene was adsorbed.

[0036] [Table 4]

[0037] Example 5 Adsorption treatment of bromotrifluoroethylene was carried out in the same manner as in Example 1, except that the temperature inside the adsorption tower was set to 60 to 70° C. As a result, the concentration of bromotrifluoroethylene was 503.97 ppm by volume 15 minutes after the start of supply of the mixed gas, and the concentration of bromotrifluoroethylene was 2222.22 ppm by volume 20 minutes after the start of supply of the mixed gas (see Table 5 below). The reason for the decrease in adsorption capacity compared to Example 1 is believed to be that the desorption of bromotrifluoroethylene was promoted by heating the adsorbent. However, even under these conditions, 98% or more of bromotrifluoroethylene was adsorbed.

[0038] [Table 5]

[0039] Example 6 Adsorption treatment of bromotrifluoroethylene was carried out in the same manner as in Example 1, except that the temperature inside the adsorption tower was set to 0 to 5°C. As a result, the concentration of bromotrifluoroethylene for 30 minutes immediately after the start of the supply of the mixed gas was 19.84 to 206.35 ppm by volume (see Table 6 below). The reason for the improvement in adsorption capacity compared to Example 1 is believed to be that desorption of bromotrifluoroethylene was suppressed by cooling the adsorbent.

[0040] [Table 6]

[0041] Example 7 Adsorption treatment of 1-bromo-1-fluoroethylene was carried out in the same manner as in Example 1, except that a mixed gas of 1-bromo-1-fluoroethylene and dry nitrogen (content of 1-bromo-1-fluoroethylene in the mixed gas was 20% by volume) was used as the bromofluoroethylene-containing gas. As a result, the concentration of 1-bromo-1-fluoroethylene for 30 minutes immediately after the start of supplying the mixed gas was 178.57 to 202.38 ppm by volume (see Table 7 below). That is, when molecular sieve 13X was used as the adsorbent, 99.90 to 99.91% of 1-bromo-1-fluoroethylene was adsorbed by the adsorbent.

[0042] [Table 7]

[0043] Example 8 Adsorption treatment of 1-bromo-1-fluoroethylene was carried out in the same manner as in Example 7, except that coal-based activated carbon (manufactured by Osaka Gas Chemicals Co., Ltd.) was used as the adsorbent instead of molecular sieve 13X. As a result, the concentration of 1-bromo-1-fluoroethylene for 30 minutes immediately after the start of supplying the mixed gas was 23.81 to 206.35 ppm by volume (see Table 8 below). In other words, when coal-based activated carbon was used as the adsorbent, 99.90 to 99.99% of 1-bromo-1-fluoroethylene was adsorbed by the adsorbent.

[0044] [Table 8]

[0045] Example 9 Adsorption treatment of 1-bromo-2-fluoroethylene was carried out in the same manner as in Example 1, except that a mixed gas of 1-bromo-2-fluoroethylene (a mixture of equimolar amounts of (E)-1-bromo-2-fluoroethylene and (Z)-1-bromo-2-fluoroethylene) and dry nitrogen (the content of 1-bromo-2-fluoroethylene in the mixed gas was 20% by volume) was used as the bromofluoroethylene-containing gas. As a result, the concentration of 1-bromo-2-fluoroethylene for 30 minutes immediately after the start of supplying the mixed gas was 162.70 to 285.71 ppm (see Table 9 below). That is, when molecular sieve 13X was used as the adsorbent, 99.86 to 99.92% of 1-bromo-2-fluoroethylene was adsorbed by the adsorbent.

[0046] [Table 9]

[0047] Example 10 Adsorption treatment of 1-bromo-2-fluoroethylene (a mixture of equimolar amounts of (E)-1-bromo-2-fluoroethylene and (Z)-1-bromo-2-fluoroethylene) was carried out in the same manner as in Example 9, except that coal-based activated carbon (manufactured by Osaka Gas Chemicals Co., Ltd.) was used instead of molecular sieve 13X as the adsorbent. As a result, the concentration of 1-bromo-2-fluoroethylene for 30 minutes immediately after the start of supplying the mixed gas was 19.84 to 166.67 ppm by volume (see Table 10 below). In other words, when coal-based activated carbon was used as the adsorbent, 99.92 to 99.99% of 1-bromo-2-fluoroethylene was adsorbed by the adsorbent.

[0048] [Table 10]

[0049] Example 11 Adsorption treatment of 1-bromo-2,2-difluoroethylene was carried out in the same manner as in Example 1, except that a mixed gas of 1-bromo-2,2-difluoroethylene and dry nitrogen (content of 1-bromo-2,2-difluoroethylene in the mixed gas was 20% by volume) was used as the bromofluoroethylene-containing gas. As a result, the concentration of 1-bromo-2,2-difluoroethylene for 30 minutes immediately after the start of supplying the mixed gas was 150.79 to 246.03 ppm by volume (see Table 11 below). That is, when molecular sieve 13X was used as the adsorbent, 99.88 to 99.92% of 1-bromo-2,2-difluoroethylene was adsorbed by the adsorbent.

[0050] [Table 11]

[0051] Example 12 Adsorption treatment of 1-bromo-2,2-difluoroethylene was carried out in the same manner as in Example 11, except that coal-based activated carbon (manufactured by Osaka Gas Chemicals Co., Ltd.) was used as the adsorbent instead of molecular sieve 13X. As a result, the concentration of 1-bromo-2,2-difluoroethylene for 30 minutes immediately after the start of supplying the mixed gas was 23.81 to 206.35 ppm by volume (see Table 12 below). In other words, when coal-based activated carbon was used as the adsorbent, 99.90 to 99.99% of 1-bromo-2,2-difluoroethylene was adsorbed by the adsorbent.

[0052] [Table 12]

[0053] Comparative Example 1 Adsorption treatment of bromotrifluoroethylene was carried out in the same manner as in Example 1, except that B-type silica gel (manufactured by Toyoda Chemical Industry Co., Ltd.) was used as the adsorbent instead of molecular sieve 13X. The average pore diameter of the pores of B-type silica gel is 6.0 nm. As a result, within 2 minutes from the start of the supply of the mixed gas, bromotrifluoroethylene was detected at a concentration exceeding the quantitative measurement limit (8000 ppm). In other words, when B-type silica gel was used as the adsorbent, bromotrifluoroethylene was not adsorbed.

[0054] Comparative Example 2 Bromotrifluoroethylene adsorption was carried out in the same manner as in Example 1, except that molecular sieve 3A (manufactured by Union Showa Co., Ltd.) was used as the adsorbent instead of molecular sieve 13X. The average pore size of the pores in molecular sieve 3A is 0.3 nm. As a result, immediately after the start of the supply of the mixed gas, bromotrifluoroethylene was detected at a concentration exceeding the quantitative measurement limit (8000 ppm). In other words, when molecular sieve 3A was used as the adsorbent, bromotrifluoroethylene was not adsorbed.

[0055] Comparative Example 3 Bromotrifluoroethylene adsorption treatment was carried out in the same manner as in Example 1, except that γ-alumina (manufactured by Kojundo Chemical Laboratory Co., Ltd.) was used as the adsorbent instead of molecular sieve 13X. The average pore size of the pores of γ-alumina is 8.5 nm. As a result, immediately after the start of the supply of the mixed gas, bromotrifluoroethylene was detected at a concentration exceeding the quantitative measurement limit (8000 ppm). In other words, when γ-alumina was used as the adsorbent, bromotrifluoroethylene was not adsorbed.

[0056] Comparative Example 4 The adsorption treatment of bromotrifluoroethylene was carried out in the same manner as in Example 1, except that the temperature in the adsorption tower was set to 120° C. As a result, immediately after the start of the supply of the mixed gas, bromotrifluoroethylene was detected at a concentration exceeding the quantitative measurement limit (8000 ppm). In other words, when the temperature in the adsorption tower was high, 120° C. or higher, bromotrifluoroethylene was not adsorbed.

[0057] Comparative Example 5 Adsorption treatment of 2-bromo-1,1,3,3,3-pentafluoropropene was carried out in the same manner as in Example 4, except that a mixed gas of 2-bromo-1,1,3,3,3-pentafluoropropene and dry nitrogen (content of 2-bromo-1,1,3,3,3-pentafluoropropene in the mixed gas was 20% by volume) was used as the treatment gas. As a result, immediately after the start of supplying the mixed gas, 2-bromo-1,1,3,3,3-pentafluoropropene was detected at a concentration exceeding the quantitative measurement limit (8000 ppm). In other words, when molecular sieve 5A was used as the adsorbent, 2-bromo-1,1,3,3,3-pentafluoropropene was not adsorbed.

[0058] Comparative Example 6 The adsorption treatment of 2-bromo-1,1,3,3,3-pentafluoropropene was carried out in the same manner as in Example 1, except that a mixed gas of 2-bromo-1,1,3,3,3-pentafluoropropene and dry nitrogen (content of 2-bromo-1,1,3,3,3-pentafluoropropene in the mixed gas was 20% by volume) was used as the treatment gas. As a result, 10 minutes after the start of the supply of the mixed gas, 2-bromo-1,1,3,3,3-pentafluoropropene was detected at a concentration exceeding the quantitative measurement limit (8000 ppm). That is, when molecular sieve 13X was used as the adsorbent, the result was obtained that the adsorption amount of 2-bromo-1,1,3,3,3-pentafluoropropene was inferior to the adsorption amount of bromotrifluoroethylene. [Explanation of symbols]

[0059] 1 Gas treatment equipment 2 Bromofluoroethylene gas supply mechanism 3. Inert gas supply mechanism 4 Supply inlet 5 Outlet 6 Adsorption tower 7. Adsorbents 8. Fourier transform infrared spectrophotometer 9 Disposal piping

Claims

1. A gas treatment method comprising the steps of: bringing a gas containing bromofluoroethylene into contact with an adsorbent having pores with an average pore size of 0.4 nm or more and 4 nm or less in a temperature environment of 0°C or more and 70°C or less, and adsorbing the bromofluoroethylene into the adsorbent, thereby separating the bromofluoroethylene from the gas, wherein the adsorbent is at least one of zeolite and activated carbon.

2. The gas processing method according to claim 1, wherein the bromofluoroethylene is at least one of bromotrifluoroethylene, 1-bromo-2,2-difluoroethylene, (E)-1-bromo-1,2-difluoroethylene, (Z)-1-bromo-1,2-difluoroethylene, 1-bromo-1-fluoroethylene, (E)-1-bromo-2-fluoroethylene, (Z)-1-bromo-2-fluoroethylene, 1,1-dibromo-2-fluoroethylene, (E)-1,2-dibromo-2-fluoroethylene, (Z)-1,2-dibromo-2-fluoroethylene, and tribromofluoroethylene.

3. 3. The gas treatment method according to claim 1, wherein the gas containing bromofluoroethylene is a mixed gas of the bromofluoroethylene and an inert gas.

4. 4. The gas processing method according to claim 3, wherein the inert gas is at least one of nitrogen gas, helium, argon, neon, and krypton.

5. 5. The gas processing method according to claim 1, wherein the content of said bromofluoroethylene in the gas containing said bromofluoroethylene is less than 25% by volume.

6. A gas treatment apparatus comprising an adsorption treatment vessel containing an adsorbent having pores with an average pore diameter of 0.4 nm to 4 nm, the apparatus subjecting a gas containing bromofluoroethylene to an adsorption treatment with the adsorbent in a temperature environment of 0° C. to 70° C., The adsorbent is at least one of zeolite and activated carbon, The adsorption treatment container has a supply port through which the gas containing bromofluoroethylene is supplied, and a discharge port through which treated gas obtained by subjecting the gas containing bromofluoroethylene to adsorption treatment with the adsorbent is discharged from within the adsorption treatment container to the outside.

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