KR20190092373A - Radioactive Material Removal Filter, Radioactive Material Removal Filter Unit Using The Method And Removal Method Of Radioactive Material - Google Patents

Abstract

Radioactive material removal filter, radioactive material removal filter unit and radioactive material removal using the radioactive material removal filter, which can suppress the deterioration of radioactive material removal even if the gas contains organic solvents, especially high boiling point compounds having a boiling point of 120 degrees or more. Provide a method. The activated carbon fiber layer 2 is provided on the downstream side and the activated carbon particle layer 3 on the upstream side, and the activated carbon fiber layer 2 has fibrous activated carbon with an amine compound attached thereto, and the amount of the amine compound attached to the activated carbon particle layer 3 The ratio of the adhesion amount of the amine compound of the activated carbon fiber layer 2 (the adhesion amount of the amine compound of the activated carbon particle layer 3 / the amine compound adhesion amount of the activated carbon fiber layer 2) is 0.1 or less (including 0).

Description

Radioactive Material Removal Filter, Radioactive Material Removal Filter Unit Using The Method And Removal Method Of Radioactive Material

The present invention relates to a radioactive material removal filter, and more particularly, to a radioactive material removal filter for removing radioactive material, particularly radioactive iodine and organic iodine compounds contained in a gas.

In facilities that handle radioactive materials such as medical facilities and nuclear facilities, it is necessary to remove generated gaseous radioactive materials from the air, and radioactive material removal filters are used. As a radioactive substance removal filter for removing gaseous iodine, a processing method for collecting and removing gaseous iodine by passing air through an activated carbonized sheet-like charcoal filter is known (see Patent Document 1, for example).

As a radioactive substance removal filter for removing organic iodine compounds in addition to gaseous iodine, activated carbon having a pore volume of pore diameter of 3 to 30 nm is 0.15 cc / g or less and a pore volume of pore diameter of 3 nm or less is 0.50 cc / g or more. The radioactive substance removal filter which has the filter medium formed by the sheet | seat containing impregnating an amine and laminating | stacking a protective sheet on at least one of the sheet | seat containing this activated carbon is known (for example, refer patent document 2).

Japanese Patent Laid-Open No. 2003-66191 Japanese Patent Laid-Open No. 2004-205490

However, in facilities handling such radioactive materials, liquid scintillation counters are used to measure radiation. As a liquid scintillation cocktail used for a liquid scintillation counter, the organic solvent which is a high boiling point compound with a boiling point of 120 degree or more, such as 1,2, 4- trimethylbenzene and a linear dodecylbenzene, is used. Therefore, in addition to gaseous radioactive substances, these organic solvents (VOC) in gaseous state are contained in trace amounts in the exhaust gas of the facility. The organic solvent of a high boiling point compound adheres to the radioactive material removal filters like patent document 1 and patent document 2, and has become a deterioration factor of the removal performance of the radioactive material using these radioactive material removal filters.

The present invention has been made in view of the above circumstances, and an object thereof is to provide for a radioactive substance such as a radioactive iodine and an organic iodine compound even if the gas contains an organic solvent in a gas state, particularly a high boiling point compound having a boiling point of 120 degrees or more. A radioactive material removal filter capable of suppressing a deterioration in removal performance, a radioactive material removal filter unit using the radioactive material removal filter, and a method for removing radioactive material are provided.

The radioactive material removal filter of the present invention, which has solved the above problems, has an activated carbon fiber layer on the downstream side and an activated carbon particle layer on the upstream side, and the activated carbon fiber layer has fibrous activated carbon with an amine compound attached thereto, and an activated carbon particle layer The ratio of the amine compound adhesion amount and the amine compound adhesion amount of the activated carbon fiber layer (the amine compound adhesion amount of the activated carbon particle layer / the amine compound adhesion amount of the activated carbon fiber layer) is 0.1 or less (including 0).

Since the radioactive substance removal filter of this invention adsorbs the organic solvent in gas in an upstream activated carbon particle layer, the downstream activated carbon fiber layer prevents the fall of the removal performance of the radioactive iodine and organic iodine compound by an organic solvent. It becomes possible.

In the radioactive substance removal filter of the present invention, the amine compound is preferably water-soluble, more preferably triethylenediamine.

In the radioactive substance removal filter of this invention, it is preferable that the adhesion amount of the amine compound of an activated carbon fiber layer is 5 mass% or more and 20 mass% or less of fibrous activated carbon.

In the radioactive material removal filter of the present invention, the weight per unit area of the fibrous activated carbon of the activated carbon fiber layer is preferably 150 g / m 2 or more and 900 g / m 2 or less.

In the radioactive material removal filter of the present invention, the weight per unit area of the granular activated carbon of the activated carbon particle layer is preferably 150 g / m 2 or more and 900 g / m 2 or less.

In the radioactive material removal filter of the present invention, the BET specific surface area of the fibrous activated carbon is preferably 800 m 2 / g or more.

In the radioactive material removal filter of the present invention, the BET specific surface area of the granular activated carbon is preferably 800 m 2 / g or more.

In the radioactive material removal filter of the present invention, the total pore volume of the fibrous activated carbon is preferably 0.3 cc / g or more.

In the radioactive material removal filter of the present invention, the total pore volume of the granular activated carbon is preferably 0.3 cc / g or more.

In the radioactive material removal filter of the present invention, the average fiber diameter of the fibrous activated carbon is preferably 10 µm or more and 40 µm or less.

In the radioactive material removal filter of the present invention, the average particle diameter of the granular activated carbon is preferably 200 µm or more and 700 µm or less.

In the radioactive material removal filter of the present invention, it is preferable that the activated carbon fiber layer and the activated carbon particle layer are laminated and have a pleated shape.

The present invention also includes a radioactive material removing filter unit and a method of removing the radioactive material, including the radioactive material removing filter.

The radioactive substance removal filter of this invention is equipped with the activated carbon fiber layer which has a fibrous activated carbon with an amine compound in a downstream side, and is equipped with the activated carbon particle layer which has granular activated carbon in an upstream side. By having an activated carbon fiber layer on the downstream side and an activated carbon particle layer on the upstream side, even if the organic solvent is contained in the gas, the removal performance for radioactive substances such as radioactive iodine and organic iodine compounds of the radioactive substance removal filter is deteriorated. It becomes possible to suppress, and can exhibit the radioactive substance removal effect of a radioactive substance removal filter for a long time.

1 shows a schematic diagram of a radioactive material removal filter in an embodiment of the present invention.
Fig. 2 shows a schematic cross-sectional view after pleating the radioactive substance removing filter in the embodiment of the present invention.
3 shows a perspective view of the radioactive material removing filter unit in the embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although the radioactive material removal filter which concerns on this invention is demonstrated concretely, referring drawings, this invention is not limited to the example of course, but the change suitably in the range which may be suitable for the meaning mentioned before and after. It is also possible to add and implement, and they are all included in the technical scope of this invention.

The radioactive material removing filter according to the present invention has an activated carbon fiber layer on the downstream side and an activated carbon particle layer on the upstream side, and the activated carbon fiber layer has fibrous activated carbon to which an amine compound is attached, and the amount and activity of the amine compound attached to the activated carbon particle layer The ratio of the adhesion amount of the amine compound of the carbon fiber layer is 0.1 or less (including 0). Hereinafter, the downstream side, the upstream side, the activated carbon fiber layer, and the activated carbon particle layer in this invention are demonstrated, respectively.

In the present invention, the downstream side is the side after the gas has passed through the filter, and means the gas outlet side. The upstream side is a side before the gas passes through the filter opposite to the downstream side, and means the gas inflow side. The arrow of FIG. 1 and FIG. 2 shows the flow of gas, The upper side of FIG. 1 and FIG. 2 is an upstream side, and the lower side is a downstream side.

The activated carbon fiber layer 2 is a layer having fibrous activated carbon to which an amine compound is attached. Fibrous activated carbon is fibrous activated carbon obtained by carbonizing a natural fiber, a regenerated fiber, or a synthetic fiber, and performing an activation reaction by gas activation.

The activated carbon fiber layer 2 is obtained by laminating a nonwoven fabric on both sides of sheet-like fibrous activated carbon and performing an integration treatment.

The BET specific surface area of the fibrous activated carbon is preferably 800 m 2 / g or more, more preferably 1000 m 2 / g or more, and even more preferably 1200 m 2 / g or more. By the lower limit of the BET specific surface area of the fibrous activated carbon being this value, the radioactive substance removal effect of the activated carbon fiber layer 2 can be enhanced.

The total pore volume of the fibrous activated carbon is preferably 0.3 cc / g or more, more preferably 0.4 cc / g or more, and still more preferably 0.5 cc / g or more. When the lower limit of the total pore volume of the fibrous activated carbon becomes this value, the effect of removing the radioactive substance in the activated carbon fiber layer 2 becomes high.

10 micrometers or more are preferable and, as for the average fiber diameter of fibrous activated carbon, 12 micrometers or more are more preferable. The lower limit of the average fiber diameter of fibrous activated carbon becomes such a value, and the air permeability of the activated carbon fiber layer 2 can be improved. Moreover, 40 micrometers or less are preferable, 35 micrometers or less are more preferable, and, as for the average fiber diameter of fibrous activated carbon, 30 micrometers or less are more preferable. By the upper limit of the average fiber diameter of fibrous activated carbon being such a value, the surface area of the activated carbon fiber layer 2 becomes large, and the removal efficiency of a radioactive substance improves.

Fibrous activated carbon is observed at 500 times magnification using an electron microscope, and the fiber diameter is measured. Arbitrary 100 fiber diameters are averaged, and this average value is made into the average fiber diameter of fibrous activated carbon.

Specific examples of the amine compound include 1,4-diazabicyclo [2,2,2] octane (triethylenediamine), N, N'-bis (3-aminopropyl) piperazine, and N, N-dimethylaminoethyl meta Acrylate, N, N-dimethylaminopropylamine, 3-aminopropyltrimethoxysilane, 1,5-diazabicyclo undecene, polyethyleneimine, 1,5-diazabicyclo [4.3.0] nonene, 1, 8-diazabicyclo [5.4.0] -7-undecene, 2-methyl-1,4-diazabicyclo [2.2.2] octane, phenylhydrazine, 2-cyanopyridine, diisopropylamine, N, N ', N'-trimethylaminoethyl piperazine, hexamethylenetetramine, a polyalkyl polyamine, etc. are mentioned. Especially, it is preferable that it is water-soluble, and, as for the amine compound to be used, it is more preferable that it is 1, 4- diazabicyclo [2, 2, 2] octane (triethylenediamine). By using a water-soluble amine compound, manufacture of the activated carbon fiber layer 2 becomes easy, and a high radioactive material removal effect can be acquired by using triethylenediamine.

5 mass% or more of fibrous activated carbon is preferable, as for the adhesion amount of the amine compound of the activated carbon fiber layer 2, 7 mass% or more is more preferable, and its 10 mass% or more is more preferable. When the lower limit of the adhesion amount of the amine compound of the activated carbon fiber layer 2 is this value, the radioactive organic iodine compound can be sufficiently adsorbed. Moreover, it is preferable that the adhesion amount of the amine compound of the activated carbon fiber layer 2 is 20 mass% or less of fibrous activated carbon, It is more preferable that it is 17 mass% or less, It is further more preferable that it is 15 mass% or less. By the upper limit of the adhesion amount of the amine compound of the activated carbon fiber layer 2 being this value, cost can be held down while maintaining a sufficient radioactive substance removal effect.

The method of adhering an amine compound to the activated carbon fiber layer 2 includes a method of immersing and drying a sheet-like fibrous activated carbon in a solution of an amine compound, a method of spraying a solution of the amine compound onto a sheet-like fibrous activated carbon and drying the fibrous activated carbon. The method of forming in a sheet form after being immersed in the solution of an amine compound and drying is mentioned. Especially, it is preferable to attach an amine compound to the activated carbon fiber layer 2 by the method of immersing and drying a sheet-like fibrous activated carbon in the solution of an amine compound. By attaching an amine compound to the activated carbon fiber layer 2 in this way, an amine compound can be made to adhere uniformly to fibrous activated carbon, and the radioactive substance removal effect of the activated carbon fiber layer 2 becomes high.

The weight per unit area of the fibrous activated carbon in the activated carbon fiber layer 2 is preferably 150 g / m 2 or more, more preferably 200 g / m 2 or more, and even more preferably 400 g / m 2 or more. When the lower limit of the weight per unit area of the fibrous activated carbon in the activated carbon fiber layer 2 is this value, the radioactive substance removing effect of the activated carbon fiber layer 2 is sufficient. In addition, the weight per unit area of the fibrous activated carbon in the activated carbon fiber layer 2 is preferably 900 g / m 2 or less, more preferably 800 g / m 2 or less, and even more preferably 700 g / m 2 or less. By the upper limit of the weight per unit area of the fibrous activated carbon in the activated carbon fiber layer 2 being this value, the weight of the activated carbon fiber layer 2 can be reduced and the pressure loss can be reduced.

The activated carbon particle layer 3 is a layer having granular activated carbon. Granular activated carbon is granular activated carbon obtained by carbonizing coconut shell, sawdust, bamboo, etc., coal, pitch, etc., by performing activation reaction by gas activation or chemical activation. Examples of the granular activated carbon include crushed coal, granulated coal, coal briquettes, and the like, and any kind of granular activated carbon can be suitably used. In addition to the granular activated carbon, it is also possible to use powdered activated carbon which is powdered activated carbon, but in order to reduce the pressure loss, it is preferable to use granular activated carbon.

The activated carbon particle layer 3 is obtained by mixing granular activated carbon and a thermoplastic resin, sandwiching the mixture between nonwoven fabrics, and performing a heat treatment.

The BET specific surface area of the granular activated carbon is preferably 800 m 2 / g or more, more preferably 900 m 2 / g or more, and even more preferably 1000 m 2 / g or more. By the lower limit of the BET specific surface area of the granular activated carbon being this value, the effect that the activated carbon particle layer 3 removes the organic solvent can be improved.

It is preferable that the total pore volume of granular activated carbon is 0.3 cc / g or more, It is more preferable that it is 0.4 cc / g or more, It is further more preferable that it is 0.5 cc / g or more. When the lower limit of the total pore volume of the granular activated carbon becomes this value, the effect of the organic solvent removal of the activated carbon particle layer 3 improves.

200 micrometers or more are preferable and, as for the average particle diameter of granular activated carbon, 250 micrometers or more are more preferable. By the lower limit of the average particle diameter of the granular activated carbon being such a value, the air permeability of the activated carbon particle layer 3 can be improved. Moreover, 700 micrometers or less are preferable, as for the average particle diameter of granular activated carbon, 625 micrometers or less are more preferable, 550 micrometers or less are more preferable. By the upper limit of the average particle diameter of granular activated carbon being such a value, the surface area of the activated carbon particle layer 3 becomes large, and the efficiency which removes an organic solvent improves.

Granular activated carbon is observed at 35 times magnification using an optical microscope, and the particle diameter is measured. Arbitrary 100 particle diameters are averaged, and this average value is made into the average particle diameter of granular activated carbon.

It is preferable that the weight per unit area of the granular activated carbon in the activated carbon particle layer 3 is 150 g / m <2> or more, It is more preferable that it is 200 g / m <2> or more, It is more preferable that it is 250 g / m <2> or more. Since the lower limit of the weight per unit area of the granular activated carbon in the activated carbon particle layer 3 becomes this value, it becomes possible to give the activated carbon particle layer 3 sufficient organic solvent removal effect. In addition, the weight per unit area of the granular activated carbon in the activated carbon particle layer 3 is preferably 900 g / m 2 or less, more preferably 800 g / m 2 or less, and even more preferably 700 g / m 2 or less. By the upper limit of the weight per unit area of the granular activated carbon in the activated carbon particle layer 3 being this value, the activated carbon particle layer 3 can be made lightweight and the pressure loss can be reduced.

The ratio of the amine compound adhesion amount of the activated carbon particle layer 3 and the amine compound adhesion amount of the activated carbon fiber layer 2 (the amine compound adhesion amount of the activated carbon particle layer 3 / the amine compound adhesion amount of the activated carbon fiber layer 2) is 0.1 or less. It is preferable that it is 0.08 or less, and it is more preferable that it is 0.06 or less. In addition, the ratio of the adhesion amount of the amine compound of the activated carbon particle layer 3 and the adhesion amount of the amine compound of the activated carbon fiber layer 2 includes zero. By the ratio of the adhesion amount of the amine compound of the activated carbon particle layer 3 and the adhesion amount of the amine compound of the activated carbon fiber layer 2 to this value, the organic solvent in the gas is removed from the active carbon particle layer 3, and the organic solvent is activated. It is prevented from adhering to the carbon fiber layer 2. Therefore, the fall of the radioactive substance removal performance of the radioactive substance removal filter 1 can be suppressed, and it becomes possible to lengthen a radioactive substance removal filter.

It is preferable that the activated carbon fiber layer 2 and the activated carbon particle layer 3 are laminated repeatedly in the thickness direction, and have a pleated shape in which bending and folding of the acid fold and the valley fold are alternately repeated. By stacking the activated carbon fiber layer 2 and the activated carbon particle layer 3, it becomes possible to miniaturize the radioactive substance removal filter 1. In addition, when the activated carbon fiber layer 2 and the activated carbon particle layer 3 have a pleat shape, the area in contact with the base becomes large, and the radioactive substance in the base can be efficiently removed.

The radioactive substance removal filter 1 according to the present invention can be used for the radioactive substance removal filter unit 11. As an example of embodiment, the radioactive substance removal filter unit 11 can be manufactured by accommodating the radioactive substance removal filter 1 in the frame 12 as shown in FIG. The material of the frame 12 is not specifically limited, For example, a metal, synthetic resin, a wood, etc. are mentioned. Especially, it is preferable that it is a metal. When the frame 12 is made of metal, the strength of the radioactive substance removal filter unit 11 can be increased.

In the radioactive material removal method according to the present invention, a gas containing radioactive material such as gaseous iodine or organic iodine compound is passed through the radioactive material removal filter 1 of the present invention. Thereby, it becomes possible to remove a radioactive substance from the said gas. Even if the organic solvent is contained in the gas, since the organic solvent is removed from the gas by the activated carbon particle layer 3 of the radioactive material removal filter 1, the organic solvent becomes difficult to adhere to the activated carbon fiber layer 2, It is possible to prevent the radioactive material removal performance of the activated carbon fiber layer 2 from being lowered.

This application claims the benefit of priority based on Japanese Patent Application No. 2016-243467 for which it applied on December 15, 2016. The entire contents of the specification of Japanese Patent Application No. 2016-243467, filed December 15, 2016, are incorporated herein by reference.

Example

Hereinafter, the effect of this invention is shown further more concretely by an Example. The following examples are not of the nature of limiting the present invention, and all of the design changes are included in the technical scope of the present invention according to the purpose of the foregoing and the following.

(Manufacturing Method of Activated Carbon Fiber Layer)

Although one sheet-like fibrous activated carbon or a plurality of sheets were laminated, an activated carbon fiber layer was produced by laminating polypropylene spunlace (weight 35 g / m 2 per unit area) on both sides and integrating by needle punching.

(Method for Producing an Activated Carbon Particle Layer)

The mixed powder was prepared such that the granular activated carbon and the thermoplastic powder resin SK-PE20L (Seincin Co., Ltd.) were granular activated carbon: powder resin = 10: 1 in a mass ratio. The prepared mixed powder was sprayed onto a thermal bond nonwoven fabric (weight 27 g / m 2 per unit area), and the same thermal bond nonwoven fabric was superimposed thereon, followed by heat treatment to prepare an activated carbon particle layer.

(Measurement method of BET specific surface area and total pore volume)

About 100 mg of sample was taken with each of granular activated carbon and fibrous activated carbon, vacuum-dried at 120 degreeC for 24 hours, and weighed. Measurement of 40 points using the automatic specific surface area measuring device Gemini 2375 (manufactured by Micromeritics Co., Ltd.) while gradually increasing the adsorption amount of nitrogen gas at the boiling point (-195.8 ° C) of liquid nitrogen in the range of 0.02 to 0.95. And the adsorption isotherm of the said sample was created. With the analysis software (GEMINI-PCW version 1.01) attached to the automatic specific surface area measuring apparatus Gemini 2375, the surface area analysis range was set to 0.01 to 0.15 under BET conditions, and the BET specific surface area [m 2 / g] was obtained. Moreover, the total pore volume [cc / g] was calculated | required from the data of relative pressure 0.95.

(Measurement method of amine compound adhesion amount)

About 300 mg of samples were collected with granular activated carbon or fibrous activated carbon, and the amine compound content was measured using GC / MS (7890A / 5975C, Agilent Technologies) about the liquid extracted from 10 mL of chloroform. The amine compound adhesion amount [mass%] was computed by dividing it by the weight of a sample.

(Organic Solvent Load Test)

The sample was set in the glass tube of 44 mm of internal diameters, and air of 25 degreeC and 0% RH of humidity containing 100 ppm of 1,2,4-trimethylbenzene (boiling point of 169 degreeC) was circulated continuously for 6 hours at 6 L / min.

(Measurement Method of Methyl Iodide Removal Rate)

The sample was set in the glass tube of 25 mm of internal diameters, and air of 25 degreeC and 0% RH of humidity containing 10 ppm of methyl iodide was continuously distributed at 5 L / min. Five minutes after the start of distribution, the gas on the inlet side and the outlet side of the sample was collected, and the methyl iodide concentration was measured in a gas chromatograph (GC-2014, manufactured by Shimadzu Corporation) with ECD, and the methyl iodide removal rate was determined from the ratio. [%] Was calculated.

(Example 1)

625 mg of triethylenediamine (Tokyo Kasei Kogyo Co., Ltd.) was dissolved in 250 g of ion-exchanged water to prepare an aqueous solution of triethylenediamine. 6 g of sheet-like fibrous activated carbon (BET specific surface area: 1460 m 2 / g, total pore volume: 0.63 cc / g, weight per unit area: 200 g / m 2, average fiber diameter: 13 μm) were added to the prepared aqueous solution, followed by room temperature. Stir at 12 h. Then, the fibrous activated carbon with sheet-like amine compound of 10.3 mass% of amine compound adhesion amounts was obtained when the fibrous activated carbon of sheet form was filtered and dried for 2 hours at 80 degreeC conditions. Three obtained fibrous activated carbons with a sheet-like amine compound were laminated | stacked, and the activated carbon fiber layer was produced.

Palm-shell granular activated carbon (BET specific surface area: 1350 m 2 / g, total pore volume: 0.62cc / g, particle diameter: 250 to 500 µm, average particle diameter: 320 µm) having an amount of amine compound deposition of 0% by mass (below the detection limit) ), An activated carbon particle layer was prepared such that the weight per unit area of granular activated carbon was 600 g / m 2.

The produced activated carbon particle layer was arrange | positioned upstream, the activated carbon fiber layer was arrange | positioned downstream, and the organic solvent load test was done. Then, the methyl iodide removal rate was measured using the sample after the organic solvent load test.

(Example 2)

An activated carbon fiber layer was produced in the same manner as in Example 1 except that the amount of triethylenediamine used was 1.88 g.

45 mg of triethylenediamine (Tokyo Kasei Kogyo Co., Ltd.) was dissolved in 8 g of ion-exchanged water to prepare an aqueous solution of triethylenediamine. Further, 6 g of coconut shell granular activated carbon (BET specific surface area: 1350 m 2 / g, total pore volume: 0.62 cc / g, particle diameter: 250 to 500 µm, average particle diameter: 320 µm) were mixed with an aqueous solution prepared earlier. Then, it dried at 80 degreeC conditions for 2 hours. The granular activated carbon with an amine compound of 0.7 mass% of amine compound adhesion amounts was obtained. Using the obtained granular activated carbon with an amine compound, the activated carbon particle layer was produced so that the weight per granular activated carbon unit area might be 600 g / m <2>.

The produced activated carbon particle layer was arrange | positioned upstream, the activated carbon fiber layer was arrange | positioned downstream, and the organic solvent load test was done. Then, the methyl iodide removal rate was measured using the sample after the organic solvent load test.

(Example 3)

It carried out similarly to Example 1 except having used the amount of triethylenediamine of 4.38g. In addition, the amine compound adhesion amount was 14.8 mass%.

(Example 4)

It carried out similarly to Example 1 except having the weight per granular activated carbon unit area of an activated carbon particle layer being 300 g / m <2>.

(Example 5)

It carried out similarly to Example 3 except having the weight per granular activated carbon unit area of an activated carbon particle layer being 300 g / m <2>.

(Comparative Example 1)

An activated carbon fiber layer was prepared in the same manner as in Example 3.

780 mg of triethylenediamine (Tokyo Kasei Kogyo Co., Ltd.) was dissolved in 8 g of ion-exchanged water to prepare an aqueous solution of triethylenediamine. Further, 6 g of coconut shell granular activated carbon (BET specific surface area: 1350 m 2 / g, total pore volume: 0.62 cc / g, particle diameter: 250 to 500 µm, average particle diameter: 320 µm) were mixed with an aqueous solution prepared earlier. Then, it dried at 80 degreeC conditions for 2 hours. The granular activated carbon with an amine compound of 12.1 mass% of amine compound adhesion amounts was obtained. Using the obtained granular activated carbon with an amine compound, the activated carbon particle layer was produced so that the weight per granular activated carbon unit area might be 300 g / m <2>.

The produced activated carbon particle layer was arrange | positioned upstream, the activated carbon fiber layer was arrange | positioned downstream, and the organic solvent load test was done. Then, the methyl iodide removal rate was measured using the sample after the organic solvent load test.

(Comparative Example 2)

The activated carbon particle layer and the activated carbon fiber layer were produced like Example 5, the activated carbon fiber layer was arrange | positioned upstream, the activated carbon particle layer was arrange | positioned downstream, and the organic solvent load test was done. Then, the methyl iodide removal rate was measured using the sample after the organic solvent load test.

(Comparative Example 3)

The activated carbon particle layer similar to Example 4 was arrange | positioned upstream and the activated carbon particle layer was arrange | positioned downstream and it carried out similarly to the comparative example 1 except having the weight per granular activated carbon unit area being 600 g / m <2>, and the organic solvent load test was done. . Then, the methyl iodide removal rate was measured using the sample after the organic solvent load test.

As apparent from Table 1, it is understood that in Examples 1 to 5, the methyl iodide removal rate is high and the durability to the high boiling point compound is high. In contrast, when the ratio of the adhesion amount of the amine compound of the activated carbon particle layer and the adhesion amount of the amine compound of the activated carbon fiber layer is larger than 0.1 (Comparative Example 1), when the activated carbon fiber layer is disposed upstream (Comparative Example 2), the activated carbon is downstream In the case where the fiber layer is not disposed (Comparative Example 3), the methyl iodide removal rate is all low, and it is understood that the durability to the high boiling point compound is low.

When the amine compound is attached not only to the downstream activated carbon fiber layer, which is the sample of Comparative Example 1, but also to the upstream activated carbon particle layer, the organic solvent in the gas cannot be removed by the active carbon particle layer alone, and the organic solvent is active. It reaches even a carbon fiber layer, and an organic solvent adheres to an active carbon fiber layer. Therefore, the thing of the comparative example 1 does not adhere an amine compound to the activated carbon particle layer of an upstream, but removes the radioactive substance, and the removal effect of a radioactive substance falls compared with the thing of Example 5 which stuck an amine compound only to the activated carbon fiber layer of a downstream side. It is. Therefore, it is preferable to attach an amine compound only to a downstream layer, without sticking an amine compound to an upstream layer.

When the activated carbon fiber layer is disposed on the upstream side and the activated carbon particle layer is disposed on the downstream side, which is the sample of Comparative Example 2, the organic solvent in the gas adheres to the activated carbon fiber layer which is superior in radioactive material removal performance than the activated carbon particle layer. As a result, the radioactive material removal performance of the activated carbon fiber layer is lowered. Therefore, in the comparative example 2, the removal effect of a radioactive substance falls compared with the thing of Example 5 in which the activated carbon particle layer is arrange | positioned upstream and the activated carbon fiber layer is arrange | positioned downstream. Therefore, it is preferable that the activated carbon particle layer is arranged on the upstream side, and the activated carbon fiber layer is disposed on the downstream side.

When the activated carbon fiber layer is not disposed on the downstream side, which is the sample of Comparative Example 3, and the activated carbon particle layer is disposed on both the upstream side and the downstream side, an activated carbon fiber layer having better radioactive material removal performance than the activated carbon particle layer is used. Since it does not exist, the removal effect of a radioactive substance falls. Therefore, it is preferable not only to use an activated carbon particle layer but to use both an activated carbon particle layer and an activated carbon fiber layer.

Moreover, in the comparative example 3, although the amine compound is affixed to the downstream activated carbon particle layer, the removal effect of a radioactive substance falls compared with Examples 4 and 5 which adhere the amine compound to the downstream activated carbon fiber layer. It is. Therefore, it is preferable not to attach an amine compound to an activated carbon particle layer, but to attach an amine compound to an activated carbon fiber layer.

In addition, when the activated carbon fiber layer is disposed on both the upstream side and the downstream side, it is necessary to increase the weight per unit area of the activated carbon fiber layer in order to have sufficient radioactive material removal performance. When the weight per unit area of the activated carbon fiber layer is increased, the thickness increases, and the thickness of the radioactive material removing filter also increases. As a result, there is a problem that the radioactive material removing filter is enlarged, making pleating of the radioactive material removing filter difficult. Therefore, it is preferable not only to use an activated carbon fiber layer but to use both an activated carbon particle layer and an activated carbon fiber layer.

As described above, the radioactive material removing filter of the present invention includes an activated carbon fiber layer on the downstream side and an activated carbon particle layer on the upstream side, and the activated carbon fiber layer has fibrous activated carbon with an amine compound attached thereto, and the amine compound of the activated carbon particle layer. The ratio of the adhesion amount and the amine compound adhesion amount of the activated carbon fiber layer (the amine compound adhesion amount of the activated carbon particle layer / the amine compound adhesion amount of the activated carbon fiber layer) is 0.1 or less (including 0). By such a structure, even if the organic solvent, especially a high boiling point compound with a boiling point of 120 degree or more is contained in gas, the fall of the removal performance of radioactive substances, such as radioactive iodine and an organic iodine compound, can be suppressed.

1: Radioactive Material Removal Filter
2: activated carbon fiber layer
3: activated carbon particle layer
11: Radioactive Material Removal Filter Unit
12: frame

Claims (15)

An activated carbon fiber layer on the downstream side and an activated carbon particle layer on the upstream side;
The activated carbon fiber layer has fibrous activated carbon to which an amine compound is attached,
The ratio of the amine compound adhesion amount of the activated carbon particle layer and the amine compound adhesion amount of the activated carbon fiber layer (the amine compound adhesion amount of the activated carbon particle layer / the amine compound adhesion amount of the activated carbon fiber layer) is 0.1 or less (including 0). Radioactive material removal filter. The radioactive material removing filter of claim 1, wherein the amine compound is water soluble. The radioactive material removing filter according to claim 1 or 2, wherein the amine compound is triethylenediamine. The radioactive material removal filter of any one of Claims 1-3 whose adhesion amount of the said amine compound of the said activated carbon fiber layer is 5 mass% or more and 20 mass% or less of the said fibrous activated carbon. The radioactive material removal filter of any one of Claims 1-4 whose weight per unit area of the said fibrous activated carbon in the said activated carbon fiber layer is 150 g / m <2> or more and 900 g / m <2> or less. The radioactive material removal filter of any one of Claims 1-5 whose weight per unit area of the granular activated carbon in the said activated carbon particle layer is 150 g / m <2> or more and 900 g / m <2> or less. The radioactive material removing filter according to any one of claims 1 to 6, wherein the BET specific surface area of the fibrous activated carbon is 800 m 2 / g or more. The radioactive material removal filter in any one of Claims 1-7 whose BET specific surface area of the said granular activated carbon is 800 m <2> / g or more. The radioactive material removing filter according to any one of claims 1 to 8, wherein the total pore volume of the fibrous activated carbon is 0.3 cc / g or more. The radioactive material removing filter according to any one of claims 1 to 9, wherein the total pore volume of the granular activated carbon is 0.3 cc / g or more. The radioactive material removal filter in any one of Claims 1-10 whose average fiber diameter of the said fibrous activated carbon is 10 micrometers or more and 40 micrometers or less. The radioactive material removal filter of any one of Claims 1-11 whose average particle diameter of the said granular activated carbon is 200 micrometers or more and 700 micrometers or less. The radioactive substance removing filter according to any one of claims 1 to 12, wherein the activated carbon fiber layer and the activated carbon particle layer are laminated and pleated. The radioactive substance removal filter unit which has a radioactive substance removal filter as described in any one of Claims 1-13. A radioactive material removal method according to any one of claims 1 to 13, wherein a gas containing radioactive material is passed through to remove the radioactive material from the gas.

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