JP4224169B2 - Gas adsorption element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an adsorbing element used for adsorbing organic solvent vapor and other organic gases, for example.
[0002]
[Prior art]
Painting factories and the like consume a large amount of organic solvent, and if the organic solvent vapor evaporated from the organic solvent is released into the atmosphere, the atmosphere may be polluted. Therefore, it is necessary to recover and remove the organic solvent vapor. For this reason, conventionally, means for adsorbing and recovering organic solvent vapor on an adsorbent has been used.
[0003]
Activated carbon or hydrophobic zeolite has been used as an adsorbent for the organic solvent vapor. In the case of using zeolite as an adsorbent, when trying to adsorb organic solvent vapor contained in the air using hydrophilic zeolite, moisture in the air is adsorbed on the zeolite, and adsorption of organic solvent vapor. It is necessary to use a hydrophobic zeolite because the efficiency is remarkably deteriorated.
[0004]
Zeolite is generally hydrophilic, and a method of removing alumina contained in zeolite is known as a method of hydrophobizing. An adsorbing element that adsorbs and removes organic solvent vapor using hydrophobized zeolite is known as disclosed in, for example, Japanese Patent No. 2645251.
[0005]
In designing the organic solvent vapor concentration and removal apparatus, the designer selects whether to use activated carbon or hydrophobic zeolite according to the type of gas to be adsorbed.
[0006]
[Problems to be solved by the invention]
The adsorbent used in the conventional organic solvent vapor adsorbing element as described above needs to be hydrophobized as described above. When using zeolite as an adsorbent, aluminum in the zeolite is used as a hydrophobizing method. The method of removing is generally performed.
[0007]
Although it is possible to absorb and remove most organic solvent vapors that need to be removed with conventional hydrophobized zeolites, when using various organic solvents to clean semiconductor wafers as in recent semiconductor factories Conventional hydrophobized zeolites are not sufficiently hydrophobic, and there is a problem that adsorption may be difficult depending on the type of vapor of the organic solvent.
[0008]
In addition, organic solvent vapors such as methanol and ethanol, which have strong polarities, have zeolite adsorption characteristics that are very close to that of water vapor, so that it is difficult to selectively remove organic solvent vapors when mixed with water vapor. Had.
[0009]
The tetrafluoride carbon plasma gas to the adsorbent such as zeolite is allowed to act for a technology to provide a very high hydrophobicity was developed. Although the adsorbent thus obtained has extremely high adsorption performance, it has a problem that it is difficult to handle due to its high hydrophobicity.
[0010]
In other words, when an adsorbent is manufactured by fixing a powdery adsorbent to a honeycomb body, the adsorbent is dispersed in a binder such as silica sol, and the honeycomb body is immersed in the binder in which the adsorbent is dispersed and dried. Many methods have been adopted.
[0011]
However, if the hydrophobicity of the adsorbent becomes high, the adsorbent does not become compatible with the binder when the adsorbent is put into the binder, and floats on the binder, making dispersion difficult.
[0012]
Even if the hydrophobicity of the adsorbent is increased, if the hydrophobicity of the sheets constituting the honeycomb body is low, the hydrophobicity of the entire adsorbing element will be low, and the selective adsorption of vapor and water vapor of a highly polar organic solvent will remain. There was a problem that it was difficult to remove.
[0013]
The present invention pays attention to the above-mentioned problems, and an object of the present invention is to provide an adsorption element that can be manufactured more easily and has high hydrophobicity.
[0014]
[Means for Solving the Problems]
A gas adsorbing element was constituted by a honeycomb body in which an adsorbent was fixed in advance and a tetrafluoride plasma gas was allowed to act.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention to fix the adsorbing agent having a hydroxyl group in the honeycomb body, at least a portion of the hydroxyl groups fluorine adsorbing agent which is fixed to the honeycomb body by the action of tetrafluoride carbon plasma gas Since the raw material adsorbent is fixed to the honeycomb body before being hydrophobized, the production is easy and the entire honeycomb body is hydrophobized. Has the effect of high properties.
[0016]
【Example】
Embodiments of the gas adsorption element of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing an example of the gas adsorption element of the present invention. In FIG. 1, reference numeral 1 denotes a honeycomb body which is a material for a gas adsorption element. In the honeycomb body 1, a planar sheet 2 and a corrugated sheet 3 are overlapped and wound. As the flat sheet 2 and the corrugated sheet 3, for example, paper made of ceramic fiber or glass fiber is used.
[0017]
The honeycomb body 1 made in this way is fired to remove organic substances such as a binder incorporated during paper making. For example, Y-type zeolite having a silica to alumina ratio of 10: 2 is dispersed in silica sol, and the honeycomb body is immersed in the dispersion.
[0018]
After the dispersion has sufficiently penetrated into the honeycomb body 1, the honeycomb body 1 is pulled up from the dispersion and dried with hot air at 120 ° C. for 0.5 to 1 hour to obtain the honeycomb body 1 on which the adsorbent is fixed.
[0019]
FIG. 2 is a cross-sectional view of a plasma processing apparatus used for carrying out the present invention. In FIG. 2, reference numeral 4 denotes a chamber, which is made of a conductive material such as metal, and has a strength that can withstand atmospheric pressure when the inside is evacuated. The chamber 4 is grounded.
[0020]
An upper electrode 5 is provided in the upper portion of the chamber 4. The upper electrode 5 is supported on the upper portion of the chamber 4 by a conductor 6. Further, the conductor 6 is insulated from the chamber 4 by the insulator 7, and as a result, the upper electrode 5 is supported in a state insulated from the chamber 4.
[0021]
A pipe 8 supplies carbon tetrafluoride gas to the lower surface of the upper electrode 5 and penetrates the upper surface of the chamber 4 and the upper electrode 5.
[0022]
Reference numeral 9 denotes a high-frequency power source, and a high-frequency current generated by the high-frequency power source 9 is supplied to the conductor 6 via the matching box 10. That is, the high frequency current generated by the high frequency power supply 9 is supplied to the upper electrode 5.
[0023]
Reference numeral 11 denotes a heater block, which is supported on the lower part of the chamber 4 by a support means 12 so as to be movable up and down. The heater block 11 is grounded. A holder 13 is provided on the heater block 11, and a mesh plate 14 made of stainless steel is further provided on the holder 13.
[0024]
Small holes having a diameter of about 1 μm are uniformly formed in the mesh plate 14, whereby the mesh plate 14 can be loaded with the honeycomb body 1 and can pass a plasma gas. Further, a gap 15 is formed between the mesh plate 14 and the holder 13, and plasma gas penetrating the mesh plate 14 is discharged through the gap 15.
[0025]
Reference numeral 16 denotes an exhaust port, which is provided on the side surface of the chamber 4 and communicates with the suction port of the vacuum pump 17, from which plasma gas is exhausted.
[0026]
The plasma processing apparatus used for carrying out the present invention has the above-described configuration, and the operation thereof will be described below.
[0027]
First, the honeycomb body 1 is placed on the mesh plate 14. Subsequently, the vacuum pump 17 is operated to depressurize the chamber 4 and energize the heater block 11. Then, the heat generated by the heater block 11 is transmitted to the honeycomb body 1 through the holder 13 and the entire honeycomb body 1 is heated. In this way, the honeycomb body 1 is heated to 400 ° C., and thereafter the temperature is maintained.
[0028]
Subsequently, the high frequency power supply 9 is activated to supply a high frequency current of 13.56 MHz to the upper electrode 5. Then, an alternating electric field is generated between the upper electrode 5 and the mesh plate 14. In this state, carbon tetrafluoride is supplied to the lower surface of the upper electrode 5 through the pipe 8. Then, the carbon tetrafluoride gas enters a plasma state between the upper electrode 5 and the mesh plate 14.
[0029]
This plasma carbon tetrafluoride gas acts on the Y-type zeolite fixed on the honeycomb body 1, one of the fluorine atoms of the carbon tetrafluoride is detached, and the hydrogen atom of the hydroxyl group bonded to the aluminum atom in the Y-type zeolite. Is replaced with carbon trifluoride and the hydrogen atom bonded to the silicon atom is replaced with fluorine. This reaction is shown in FIG.
[0030]
As can be seen, the Y-type zeolite has a hydroxyl group bonded to an aluminum atom, so it is not completely hydrophobic but somewhat hydrophilic. However, because this hydroxyl group is substituted with carbon trifluoride, It becomes strongly hydrophobic.
[0031]
The process of replacing the hydrogen atom of the hydroxyl group bonded to the aluminum atom with carbon trifluoride will be described in more detail. When the raw material zeolite is heated and heated to 400 ° C., hydrogen and hydroxyl groups associated with the aluminum atoms of the zeolite are removed. When carbon tetrafluoride gas in a plasma state is allowed to act for 30 minutes in this state under a pressure of 35 Pa, one fluorine of the carbon tetrafluoride gas is removed to form carbon trifluoride and fluorine, respectively, and aluminum atoms and Combines with silicon atoms.
[0032]
As described above, the hydroxyl group bonded to the aluminum atom of the Y-type zeolite has been replaced with carbon trifluoride. However, the ceramic fiber of the ceramic paper constituting the honeycomb body 1 also has a hydroxyl group bonded to the aluminum atom. Is also substituted with carbon trifluoride to be hydrophobized.
[0033]
In this way, the honeycomb body 1 on which the adsorbent is fixed is hydrophobized by the plasma reforming treatment, and even a highly polar organic solvent vapor can be preferentially adsorbed to water vapor.
[0034]
Further, as Example 2 of the present invention, an adsorbing element can be configured by laminating a plurality of honeycomb bodies 1, which will be described below. First, a plurality of honeycomb bodies 1 are prepared, and the plasma reforming process of the honeycomb body 1 is performed in the same manner as described above by changing the output of the high-frequency power source 9.
[0035]
Then, a plurality of honeycomb bodies having different degrees of modification can be obtained. That is, the plurality of honeycomb bodies have different degrees of hydrophobicity. The three honeycomb bodies 17, 18, and 19 having different degrees of hydrophobicity are stacked to obtain the adsorption element shown in FIG.
[0036]
The hydrophobicity of the three honeycomb bodies 17, 18, and 19 is set so that the hydrophobicity is low, medium, and high in order from the end, and when adsorbing an organic gas containing a lot of water vapor, the honeycomb body 17 having a low hydrophobicity is used. The adsorbed gas is allowed to flow from the side.
[0037]
Then, a large amount of water vapor and a small amount of organic gas are adsorbed on the honeycomb body 17 having a low hydrophobicity, and then a small amount of water vapor and an organic gas are adsorbed on the honeycomb body 18 having a medium hydrophobicity. For this reason, the organic gas enters the honeycomb body 19 having a high degree of hydrophobicity in a state where water vapor is almost removed.
[0038]
For this reason, in the honeycomb body 19 having a high hydrophobicity, water vapor does not interfere with the adsorption of the organic gas, and the adsorption rate is increased.
[0039]
In the above embodiment, an example in which three honeycomb bodies are stacked is shown, but the number is not limited to three, and the number can be adjusted as appropriate. That is, a large number of honeycomb bodies having specific thicknesses having different hydrophobicities are prepared in advance, and the number of stacked honeycomb bodies can be adjusted, for example, from 4 to 10 according to the target adsorption amount.
[0040]
By doing so, a specific product can be produced in a large amount and a mass production effect can be exhibited.
[0041]
【The invention's effect】
Since the gas adsorbing element of the present invention is configured as described above, the adsorbent can be fixed to the honeycomb body before being hydrophobized, and can be easily produced.
[0042]
Further, the plasma treatment can be performed in a state where the adsorbent is fixed to the honeycomb body, and the honeycomb body can be hydrophobized together with the adsorbent, so that a gas adsorption element having high hydrophobicity as a whole can be obtained.
[0043]
Furthermore, since the gas adsorbing element of the present invention has a plurality of honeycomb bodies laminated, if a large number of honeycomb bodies having specific thicknesses having different hydrophobicities are prepared in advance, the number of laminations can be adjusted as required. A thick adsorption element can be obtained. Therefore, by producing a large number of honeycomb bodies having specific thicknesses, gas adsorption elements having various thicknesses having various adsorption characteristics can be produced, and mass production effects can be exhibited.
[0044]
Moreover, since the gas adsorbing element of the present invention has a structure in which honeycomb bodies having different hydrophobicity levels are laminated, organic gas containing a large amount of water vapor can be adsorbed effectively.
[Brief description of the drawings]
FIG. 1 is a perspective view showing Example 1 of a gas adsorption element of the present invention.
FIG. 2 is a cross-sectional view showing an example of a plasma processing apparatus used in the present invention.
FIG. 3 is a view showing a chemical change in the manufacturing process of the gas adsorption element of the present invention.
FIG. 4 is a perspective view showing Example 2 of the gas adsorption element of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Honeycomb body 2 Plane sheet 3 Corrugated sheet 4 Chamber 5 Upper electrode 6 Conductor 7 Insulator 8 Pipe 9 High frequency power supply 10 Matching box 11 Heater block 12 Support means 13 Holder 14 Mesh board 15 Gap 16 Exhaust port

Claims (2)

Y-type zeolite fixed on a honeycomb body made of paper made of paper made of ceramic fibers containing hydroxyl groups bonded to aluminum atoms with a binder, and carbon tetrafluoride plasma gas acting on the Y-type zeolite An organic solvent vapor adsorption element having a honeycomb body in which at least some of the hydroxyl groups are substituted with fluorine. 2. The organic solvent vapor adsorption element according to claim 1, wherein a plurality of honeycomb bodies are laminated, and the substitution rate of the hydroxyl group to fluorine is different for each layer of the honeycomb bodies.

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