JPH09323037A - Treatment of carbon monoxide and carbon monoxide treating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix and recover gaseous carbon monoxide by making carbon monoxide adsorbed to an organometallic complex having an one- or three-dimensional channel structure as an adsorbing material and separating/removing the carbon monoxide from a subject material to be treated. SOLUTION: A gas treating device 1 is composed freely selectively of the first separation state in which the gas to be treated (gaseous hydrogen) is introduced to a adsorbing material housing chamber 3 whose pressure is set to make the carbon monoxide adsorbed to the adsorbing material, and also a residual gas is introduced to the first recovering passage 5 to be captured and the second separation state in which the carbon monoxide adsorbed to the adsorbing material 2 is desorbed and introduced to the second recovering passage 6 to be captured or to be released to atmosphere. the organometallic complex having the one- or three-dimensional channel structure is a asorbing material for the treatment which separates, removes, recovers, etc., the gaseous carbon monoxide from other gas, and when copper is incorporated into the organometallic complex as a metal, more strong separating capacity and recovering capacity are obtained since a copper carbonyl complex is formed between the carbon monoxide and the complex.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a carbon monoxide treatment method for separating and removing carbon monoxide from a treatment target containing carbon monoxide, and a carbon monoxide treatment material usable for such treatment.

[0002]

2. Description of the Related Art The following examples can be given as fields in which such carbon monoxide is separated and removed. The first example is a gas mask that is worn and used by a worker in a coal mine or the like, and activated carbon is used for such a mask to adsorb carbon monoxide. A second example is an application for removing carbon monoxide from a gas component after reforming for a natural gas fuel cell.
More specifically, in a reformer for a fuel cell, carbon monoxide and hydrogen are converted by a catalytic reaction between methane contained in natural gas and water. The carbon monoxide that is generated here becomes a catalyst poison to platinum that is a catalyst (electrode) in the fuel cell, and therefore must be removed. Conventionally, when removing such carbon monoxide, a selective oxidation catalyst such as a Cu—Zn-based catalyst is used to react carbon monoxide with oxygen and convert them into carbon dioxide. By such a treatment, the concentration of the monoxide gas in the gas obtained by the reformer is changed from 5000 ppm to 7000 pp.
It can be lowered to about m.

[0003]

SUMMARY OF THE INVENTION However,
Each technology has the following problems. When activated carbon is used in the mask, its removal efficiency is limited and there is room for improvement. On the other hand, when a Cu—Zn-based catalyst is used, for example, when the fuel cell is a phosphoric acid type, the above removal rate can be used to some extent, but it cannot be said to be sufficient. On the other hand, in the case of the polymer solid electrolyte type, the carbon monoxide concentration is 1
It must be 0 ppm or less, and cannot be used at present. Therefore, an object of the present invention is to obtain a carbon monoxide treatment method capable of removing carbon monoxide to a lower concentration with higher efficiency than ever before.

[0004]

[Means for Solving the Problems]

[Structure] To achieve this object, the characteristic means of the method for treating carbon monoxide according to claim 1 of the present invention for separating and removing the carbon monoxide from the treatment target containing carbon monoxide according to the present invention is: It is to adsorb carbon monoxide to an organometallic complex having a one-dimensional or three-dimensional channel structure as an adsorbent to remove carbon monoxide from the object to be treated. [Operation / Effect] The organometallic complex having a one-dimensional or three-dimensional channel structure used as an adsorbent in the present application has an adsorbing ability for carbon monoxide, and its structure has uniform void sizes. Therefore, carbon monoxide can be adsorbed and removed from the object to be treated with relatively good selectivity. Further, the higher the adsorptive capacity, the lower the carbon monoxide concentration can be made to be lower than ever.

In the present invention, the organometallic complex used as an adsorbent is: (1) a complex formed by a metal ion and a dicarboxylic acid having two carboxyl groups arranged at point symmetry positions in a molecule (terephthalic acid) Copper, copper fumarate, copper 1,4-trans-cyclohexanedicarboxylate, copper 4,4′-biphenyldicarboxylate, copper 2,6-naphthalenedicarboxylate, copper p-phenylene acetate, etc.),
(2) A complex formed by a bidentate organic ligand having atoms capable of coordinating to a metal ion at both ends of a rigid skeleton and a divalent metal ion (expressed by the following chemical formula: etc

[0006]

Embedded image M (bpy) _m (A ⁻ ) ₂ (M is a metal ion selected from Co, Cu, Ni and Zn, A is an anionic group, m is 1.5 or 2, bp
y represents 4,4'-bipyridyl))

Or (3) a bidentate organic ligand having atoms capable of coordinating metal ions at both ends of a rigid skeleton, formed by 2,3-pyrazinedicarboxylic acid and a divalent metal ion Complex (such as represented by the following chemical formula)

[0008]

[Image Omitted] Cu (bpy) (pyzdc) ₂ (bpy is 4,4′-bipyridyl, pyzdc is 2,3
-Represents pyrazine dicarboxylic acid))

At least one of them can be mentioned as a typical example. These complexes can be obtained by mixing and reacting a solution of an organic ligand and a solution of a metal salt as a raw material.

The dicarboxylic acids having two carboxyl groups arranged at point symmetry positions in the molecule, which are organic ligands constituting the complex of (1), include terephthalic acid, fumaric acid, 1,4- Examples are trans-cyclohexanedicarboxylic acid and 4,4′-biphenyldicarboxylic acid.
In addition, as metal ions, copper ions, chromium ions,
Examples thereof include molybdenum ion, rhodium ion, palladium ion and tungsten ion, and a complex is formed in combination with the dicarboxylic acid.

The organic ligand constituting the complex (2) includes pyrazine, 4,4'-bipyridyl, trans-1,
Those selected from 2-bis (4-pyridyl) ethylene, 1,4-dicyanobenzene, 4,4′-dicyanobiphenyl, 1,2-dicyanoethylene, and 1,4-bis (4-pyridyl) benzene are preferred. , Divalent metal ions are used as the metal ions, specifically, Co, Ni,
It is preferable to use one selected from Cu and Zn.

The organic ligand constituting the complex (3) is
One of the organic ligands used in (2) is used in combination with pyrazinedicarboxylic acid, and the same metal ion as in (2) is used.

The production of these organometallic complexes is carried out by preparing a solution of an organic ligand and a solution of a metal salt as a raw material, mixing these and reacting them. The solvent used is not particularly limited as long as it does not react with an organic ligand or a metal ion or form a complex. The counter ion of the metal ion is not particularly limited as long as it does not inhibit the solubility of the metal salt in the solvent and the formation of the one-dimensional channel structure of the resulting complex. In the production of the complex (1), it is preferable to adjust the pH by adding an organic acid to a solution of dicarboxylic acid, and formic acid, acetic acid, trifluoroacetic acid, propionic acid and the like can be used.

The analysis of the organometallic complexes (1) to (3) by X-ray diffraction analysis shows that they have a one-dimensional or three-dimensional channel structure. Taking copper terephthalate as an example of the complex of (1), copper is four-coordinate in a plane, and two copper ions are arranged so that four molecules of terephthalic acid surround every 90 °, and a carboxyl group is formed. Are coordinated to different copper ions, respectively. That is, terephthalic acid molecules are arranged in a lattice, and two copper ions exist at the lattice points. And the crystal | crystallization is comprised in the form in which the layer formed from a copper ion and a dicarboxylic acid was laminated | stacked. As a result, the lattices are stacked to form a one-dimensional channel. As the complex of (2),

Embedded image A complex having a composition of Ni (bpy) _1.5 (ClO ₄ ) ₂ (bpy represents 4,4′-bipyridyl) will be described. Around one Ni ion, every 90 ° on the plane, 4,4'-bipyridyl is 4
It is coordinated by the N atom of the molecule, and 4,4′-bipyridyl is coordinated by different N atoms to different Ni ions, forming a planar lattice, and this lattice makes the Ni ions line up in a straight line. To form a crystal, and the lattices continuously form a one-dimensional channel or a three-dimensional channel by stacking. Further, as the complex of (3),

## STR4 ## Cu (bpy) (pyzdc) ₂ (bpy is 4,4′-bipyridyl, pyzdc is 2,3
-Representing pyrazine dicarboxylic acid))), an example of a complex having the composition
Pyrazinedicarboxylic acid is coordinated with copper ions to form a planar structure, and this plane is coordinated with copper ions 4,4′-
The bipyridyl is bonded to form a layered structure to form a crystal, and a channel structure is formed in this layer. Therefore, also in this case, a one-dimensional channel or a three-dimensional channel is formed.

[Structure] Further, the characteristic means of the method for treating carbon monoxide according to claim 2 according to the present application is that carbon monoxide is adsorbed on an organometallic complex having a one-dimensional or three-dimensional channel structure as an adsorbent. It is to let it collect. [Operation / Effect] As described above, since the organometallic complex having a one-dimensional or three-dimensional channel structure has an adsorbing ability for carbon monoxide, it is possible to fix this gas by adsorbing carbon monoxide. It can be collected and converted.
Further, when adopting the method of the present application, since such a complex is harmless, it is possible to detoxify and immobilize harmful carbon monoxide and recover it.

Therefore, the organometallic complex having a one-dimensional or three-dimensional channel structure is a carbon monoxide treatment material which can be used for separation and removal of carbon monoxide gas from other gases, recovery, and the like. . Furthermore, when the organometallic complex used for such an application has copper as a metal, a copper carbonyl complex is formed between carbon monoxide and the complex, which results in a stronger separation. Ability and recovery ability can be obtained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A gas treatment apparatus 1 for removing carbon monoxide from a gas to be treated by using the method for treating carbon monoxide of the present application will be described below with reference to the drawings. In the example described below, the case where the carbon monoxide is removed from the processing target gas (hydrogen gas) in which carbon monoxide is mixed will be described. As shown in FIG. 1, a gas processing apparatus 1 includes an adsorbent storage chamber 3 for storing an adsorbent 2, and supplies a target gas to the adsorbent storage chamber 3, and the supply of the target gas can be stopped. The supply path 4 is provided with a first recovery path 5 and a second recovery path 6 that can selectively recover the gas discharged from the adsorbent storage chamber 3 between the paths. That is, the lower side of the processing target gas supply path 4 is connected to the absorbent material storage chamber 3, and in the middle of it,
A supply-side switching valve 7 is provided that can switch the path between the gas supply and the gas supply stop state. Further, the first recovery path 5 and the second recovery path 6 are each connected on their upper side to the absorbent storage chamber 3, and are provided with a first switching valve 8 and a second switching valve 9, respectively. In principle, the supply side switching valve 7 is open, the first switching valve 8 is open, and the second switching valve 9 is closed. Is closed, the first switching valve 8 can be set to the closed state and the second switching valve 9 can be set to the open state. Here, the former state corresponds to a first separation state, and the latter state corresponds to a second separation state. On the other hand, the aforementioned second recovery path 6 is provided with a pump 10 for suction, and this pump 10 operates to open the second switching valve 9 and close the first switching valve 8 (first (Corresponding to two separate states), the adsorbent storage chamber 3 can be maintained in a vacuum exhausted state (low pressure state). On the other hand, when the first switching valve 8 is open and the second switching valve 9 is closed (corresponding to the first separation state), the gas is supplied from the supply side at almost normal pressure in the adsorbent storage chamber. It will be in the state to be. Therefore, the pump 10 functions as a pressure setting mechanism that can maintain the pressure in the adsorbent storage chamber in two different pressure states depending on the operating state and the non-operating state (however, in cooperation with other valves).

By adopting the above configuration, the gas treatment device 1 of the present application guides the gas to be treated (hydrogen gas) to the adsorbent storage chamber 3 to adsorb carbon monoxide on the adsorbent, and the remaining gas. The first to collect the first to the first recovery path 5
The separated state and the carbon monoxide adsorbed on the adsorbent 2 are desorbed from the adsorbent 2, and the desorbed carbon monoxide is guided to the second recovery passage 6 to be collected or opened to the atmosphere. The state can be freely selected between the second separated state and the second separated state.

Further, copper fumarate as an example of the adsorbent 2 is accommodated in the adsorbent accommodating chamber. Further, the pressure setting mechanism desorbs the pressure in the adsorbent storage chamber to a predetermined pressure state (not a vacuum state) in the adsorption state (first separation state) in which the adsorbent 2 performs the adsorption operation. In the desorption state (second separation state) in which the operation is performed, the setting can be switched to vacuum.

An example of producing this copper fumarate will be explained. Methanol 100 cm ³ and formic acid 12
1.2 g of fumaric acid was dissolved in a mixed solvent of cm ³ . The solution was cooled to room temperature and stirred, while stirring for 3.38 g of copper formate.
Was added dropwise a solution prepared by dissolving Metanoru 100 cm ^3,
Let stand for one day. After that, the precipitate is suction filtered and the temperature is 120 ° C.
After drying for / 4 hours, the desired copper fumarate can be obtained.

The above is the configuration of the gas processing apparatus 1 of the present application. Hereinafter, the result of performing separation using this apparatus 1 will be described below. Separation Operation 1 As described above, copper fumarate was stored as the adsorbent 2 in the adsorbent storage chamber, and the gas to be treated containing carbon monoxide was circulated until adsorption saturation was reached. In this case, the processing target gas supply path 4
Also, the first recovery passage 5 was opened and the second recovery passage 6 was closed (first separated state). This operation was performed at normal temperature. This operation is called a first step. Explaining the obtained results, as shown in Table 1, only carbon monoxide could be separated from the gas to be treated.

[0022]

[Table 1] Gas composition to be treated Base gas Hydrogen-containing substance Carbon monoxide few% Component composition of gas recovered in the first recovery passage 5 Carbon monoxide was not detected in% order.

Further, after the above-mentioned first step, the gas supply passage 4 to be treated and the first recovery passage 5 were closed and the second recovery passage 6 was opened (second separated state). However, in this state, the pump 10 was operated to evacuate the adsorbent storage chamber, and the gas coming out of the adsorbent was guided to the second recovery path 6. This operation was also performed at normal temperature. This operation is called a second step. As a result, carbon monoxide could be recovered in the second recovery passage 6.

Another Embodiment Another embodiment of the present application will be described below. (A) In the above embodiment, an example in which copper fumarate is used as the adsorbent has been shown, but as described above, any organometallic complex having a one-dimensional or three-dimensional channel structure may be used. The object of the present application can be achieved. (B) In the above embodiment, the adsorbent storage chamber 3
Although a single gas is provided and a predetermined gas is alternately introduced into the first recovery passage 5 and the second recovery passage 6, the gas from which carbon monoxide is removed can be continuously recovered. It is also possible. Such a configuration is shown in FIG. In the apparatus 100 having the illustrated configuration, the pair of adsorbent storage chambers 3
And a switching valve 70 is provided in each of the processing target gas supply paths 4 connected to these adsorbent storage chambers 3.
Is provided. Further, a two-position switching valve 80 is provided which connects the discharge path 50 from each adsorbent storage chamber 3 to the first recovery path 5 and the second recovery path 6 alternatively. Also in this case, each adsorbent storage chamber 3 is provided with a pressure setting mechanism. By doing so, the exhaust gas from the adsorbent storage chamber 3 is guided to the first recovery path 5 while the gas to be treated is supplied to one of the adsorbent storage chambers 3, and the other is configured. While the supply of the gas to be treated to the adsorbent storage chamber 3 is shut off, the adsorbent 2 in the adsorbent storage chamber is maintained in a desorbed state (specifically, a reduced-pressure vacuum state). Is configured to guide the exhaust gas from the second recovery path 6. This state can be alternately switched between the adsorbent storage chambers. With this configuration,
Continuous processing becomes possible. (C) In the above embodiment, the adsorbent storage chamber 3
In contrast, a pressure setting mechanism that can set the internal pressure to two states is provided, but the switching between the adsorption state and the desorption state does not depend on the indoor pressure but the adsorption and desorption depending on the room temperature. It is good also as a structure which performs. In this case, in place of the pressure setting mechanism, a temperature setting mechanism 11 that can set the room temperature to an arbitrary temperature state (actually, two setting temperature states) may be provided. This configuration is shown in FIG. 3 corresponding to FIG. In the configuration of FIG.
Is not required, but may be provided.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a configuration of a gas processing apparatus of the present application.

FIG. 2 is a diagram showing another embodiment of the gas processing apparatus according to the present invention.

FIG. 3 is a diagram showing another embodiment of the gas processing apparatus of the present application.

[Explanation of symbols]

 2 adsorbent 3 adsorbent storage chamber 4 gas supply path to be treated 5 first recovery path 6 second recovery path

Claims (5)

[Claims] 1. A carbon monoxide treatment method for separating and removing carbon monoxide from a treatment target containing carbon monoxide, the organometallic complex having a one-dimensional or three-dimensional channel structure as an adsorbent. A method for treating carbon monoxide, which comprises adsorbing the carbon monoxide on a substrate and separating and removing the carbon monoxide from the treatment target. 2. A method for treating carbon monoxide in which carbon monoxide is adsorbed and recovered by an organometallic complex having a one-dimensional or three-dimensional channel structure as an adsorbent. 3. The method for treating carbon monoxide according to claim 1, wherein the organometallic complex has copper as a metal. 4. A carbon monoxide treatment material comprising an organometallic complex having a one-dimensional or three-dimensional channel structure. 5. The carbon monoxide treating material according to claim 4, wherein the organometallic complex has copper as a metal.