JP3927694B2 - Catalyst for detoxification of pollutants - Google Patents

Description

【００３９】
【表２】

【００４０】
【表３】

【００４１】
【表４】

【００４２】
まず、比較例１と実施例１，２との比較を行うと、木炭粉末のみの比較例１の場合には反応管４２に入れた９５ｐｐｍのＮＯ濃度が反応管４２通過後の出口ガス濃度は３８〜３９ｐｐｍとなり、実施例１，２の出口ガス濃度４６〜４９ｐｐｍと比べかなり低くなった。これは、焼結前の木炭のみの比較例１の場合には吸着作用が強く、その吸着作用によりＮＯがより強く吸着されたものと考えられる。一方、比較例１の場合にはＮ_２濃度は６３０〜７５０ｐｐｍの範囲で時間経過と共に低くなり、Ｏ_２濃度はゼロであり、Ｎ_２Ｏ濃度は１．１〜１．３ｐｐｍであったのに対し、実施例１，２ではＮ_２濃度は１０８０〜１７００ｐｐｍの範囲で時間経過と共に増加傾向を示し、Ｏ_２濃度は１０〜７０ｐｐｍであり、ＮＯ濃度は４６〜４９ｐｐｍというように比較例１と比べ大幅に高い濃度となっている。つまり反応管４２に流したＮＯがＮ_２，Ｏ_２，Ｎ_２Ｏにそれぞれ還元分解されたものと考えられる。従って、実施例１，２は比較例１に比べＮＯの還元分解能力に優れていると考えられる。
【００４３】
次に、比較例２と実施例１，２との比較を行うと、木炭／酸化チタンの複合体の比較例２の場合には反応管４２に入れた９５ｐｐｍのＮＯ濃度が反応管４２通過後の出口ガス濃度は４１〜４２ｐｐｍとなり、実施例１，２の出口ガス濃度４６〜４９ｐｐｍと比べわずかに低くなった。一方、比較例２の場合にはＮ_２濃度は７５０〜１０３０ｐｐｍの範囲、Ｏ_２濃度は１０〜３０ｐｐｍ、Ｎ_２Ｏ濃度は２．１〜２．４ｐｐｍであったのに対し、実施例１，２ではＮ_２濃度は１０８０〜１７００ｐｐｍの範囲で時間経過と共に増加傾向を示し、Ｏ_２濃度は１０〜７０ｐｐｍであり、ＮＯ濃度は４６〜４９ｐｐｍというように比較例２と比べ同等か高い濃度となっている。従って、反応管４２に流したＮＯをＮ_２，Ｏ_２，Ｎ_２Ｏにそれぞれ還元分解する能力においては、光触媒である酸化チタンを混合した比較例２に対しも実施例１，２は少なくとも同等か優れていると考えられる。
【００４４】
【発明の効果】
以上説明したように、請求項１，２，６〜８のいずれかに記載の第１の発明における汚染物質の分解無害化用触媒、または、請求項３〜８のいずれかに記載の第２の発明における汚染物質の分解無害化用触媒によれば、バイオマスを含む物質を焼成して得られた焼成炭化物をさらに高温で焼結することにより還元作用を発揮するようになる一方、その還元作用が焼結用原料に含まれた金属により増幅されるため、本分解無害化用触媒を汚染物質が含まれた空気もしくは水と接触させることにより、その汚染物質が焼結炭の有する若干の吸着作用により吸着される一方、その吸着された汚染物質もしくは接触している汚染物質を還元作用により還元分解することができるようになる。この際、含有させる金属を第２の発明の如く焼成炭化物の粉末を金属塩溶液もしくは金属アルコキシド溶液に浸漬した後に乾燥させて原料としこれを通電焼結した場合には、焼結炭の有する還元作用がこの焼結炭の微細構造内にまで均一に分散した金属により均一に増幅されることになり、汚染物質の全体としての還元分解機能も第１の発明の場合よりも向上することになる。
【００４５】
そして、上記第１及び第２の各発明の場合、触媒による汚染物質の除去は、活性炭の如く吸着して蓄えることにより周囲の雰囲気から汚染物室を除去するものではなく、還元分解することにより汚染物質を除去するものであるため、半永久的に使用可能であり、交換もしくは処分の必要がなく交換・処分に伴う問題も生じない。しかも、本質的には焼結炭の有する還元作用を利用した汚染物質の還元分解であり、その還元作用を増幅するために金属を混合分散させるものであるため、本触媒を大量にしかも容易に供給することができるようになる。加えて、上記の原料の焼結を通電焼結により行っているため、焼結と成型とが同時に行われ、従来の電気炉を用いて高温度域の焼成を行なう場合と比べて成型のための特別な装置が不要になる上に、電気炉で昇温させる場合と比べ、大幅に短時間（数分間）で焼結を完了させることができ、より一層容易に分解無害化用触媒を提供することができるようになる。
【図面の簡単な説明】
【図１】本発明の通電焼結の原理を示す断面説明図である。
【図２】通電焼結のための装置を示す模式図である。
【図３】通電焼結のための型及び原料粉末を示す一部断面斜視図である。
【図４】第１実施形態の製造方法の手順を示すフローチャートである。
【図５】触媒の利用例としての空気清浄器の断面説明図である。
【図６】第２実施形態の製造方法の手順を示すフローチャートである。
【図７】試験装置を示す模式図である。
【符号の説明】
３，２０ 混合粉末（原料粉末）
３′，２０′ 原料粉末[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst used for detoxifying and detoxifying pollutants present in air or water such as nitrogen oxide (NOx), dioxin, formaldehyde, trihalomethane and the like.
[0002]
[Prior art]
Conventionally, activated carbon is known to purify contaminants present in the air or water. This is intended to remove the contaminants from the air or water by adsorbing the contaminants by the adsorption action of the activated carbon.
[0003]
On the other hand, the thing using the titanium dioxide as a photo-semiconductor catalyst which decomposes | disassembles the trihalomethane for the trihalomethane which exists in tap water is known (refer Unexamined-Japanese-Patent No. 9-239268). In this method, charcoal having an adsorption function and pores is selected as a carrier for supporting titanium dioxide, and a mixture of titanium dioxide and charcoal is molded and used as a catalyst.
[0004]
[Problems to be solved by the invention]
However, in the adsorption removal using activated carbon as described above, when the adsorption amount reaches saturation, no further adsorption function is exhibited, and it is necessary to regenerate or replace the activated carbon in the adsorption saturated state. In this case, it is problematic from the viewpoint of environmental pollution to dispose of the activated carbon that has adsorbed the pollutant to the saturated state as it is. In addition, even if the adsorbed contaminant is taken out by the regeneration process or the activated carbon in the adsorption saturated state is disposed as it is, a difficult problem occurs depending on the kind of the adsorbed contaminant.
[0005]
On the other hand, in the case of using titanium dioxide, which is a photocatalyst, charcoal as a carrier can be obtained at a low cost, but the photocatalyst itself (titanium dioxide) is expensive, and it is feasible to use as a catalyst for dealing with a large amount of pollutants. It will be poor.
[0006]
This invention is made | formed in view of such a situation, The place made into the objective is providing what can be supplied in large quantities as a catalyst which aims at detoxification of a pollutant by decomposition | disassembly rather than adsorption | suction. is there.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present inventor has found that sintered charcoal obtained by sintering fired charcoal at a higher temperature exhibits a reducing action, and reduction of contaminants by the reducing action of the sintered charcoal. In order to further amplify this reduction action based on decomposition, a catalyst for decomposition and detoxification of pollutants is obtained by combining a metal with the sintered charcoal. Specifically, according to a first aspect of the present invention, as described in claim 1, a raw material is a mixed powder obtained by mixing a metal powder or a metal oxide powder with a calcined carbide powder obtained by calcining a material containing biomass. The raw material is obtained by discharging and sintering between the powder particles while pressurizing the raw material in a mold. According to a second aspect of the present invention, as set forth in claim 3, the powder of the fired carbide obtained by firing the material containing biomass is dipped in either a metal salt solution or a metal alkoxide solution and then dried. It is obtained by using a material as a raw material and discharging and sintering between the powder particles while pressurizing the raw material in a mold.
[0008]
Here, as the “metal powder or metal oxide powder” in the first invention, Cu, Al, Ag, Ti, Ni, Li, Si, Fe, Pt, V, Cr, Mn, Co, Zr, It is preferable to use one or more metal powders selected from Mo, Pd, K, Sn, and Au, or a metal oxide powder of one or more metals described above. Among these, Cu, Fe or oxide powder thereof is more preferable. In addition, as the “metal salt solution” in the second invention, a solution of any one of Cu, Ni, Fe, Ag, and Ti is preferable, and as the “metal alkoxide solution”, Cu, Ni, Any 1-propanol solution of Fe, Ag, and Ti is preferable.
[0009]
Furthermore, in the first or second invention, “biomass” is a biological organic resource, and is made of plant residues such as wood, bamboo, grass, coffee bean shells, paper, or cellulose such as pulp. It contains substances. Moreover, such a substance containing biomass is, for example, a composite material of the above paper, virgin pulp, waste paper or the like and a phenol resin, olefin resin or starch biodegradable resin. From the viewpoint of effective use of resources, these biomasses include, for example, waste wood such as thinned wood, sawn timber, unused wood, and house demolition materials, cut grass, coconut shells, palm trees, beer lees, juice squeezes It is preferable to use waste materials such as plant residue such as shochu, coffee lees, okara, fir shell, millet shell, and bran. Moreover, as a baked carbide obtained by baking a material containing biomass 300 ° C to 800 ° C What was baked in the temperature range up to is preferable. Furthermore, it is preferable to use only the above-mentioned raw materials without using a binder to fill the mold by the electric current sintering method. In addition, it is preferable that the above-mentioned catalyst for detoxifying and decontaminating the pollutant is one obtained by subjecting the raw material to current sintering in a reduced pressure state.
[0010]
In the case of the first invention, the reduction effect is exhibited by further sintering the fired carbide obtained by firing the material containing biomass at a higher temperature. On the other hand, since the sintering is carried out using a mixture of the above-mentioned calcined carbide and metal powder or metal oxide powder as a raw material, metal composite sintering as a decomposition and detoxification catalyst formed by sintering The reduction action of charcoal is amplified by the mixed metal. For this reason, when the metal composite sintered coal is brought into contact with air or water containing contaminants, the contaminants are adsorbed by the slight adsorption action of the sintered coal, while the adsorbed contaminants are absorbed. Substances or contaminants in contact with them will be reduced and decomposed by the reducing action.
[0011]
In the case of the second aspect of the invention, the sintered carbide powder is obtained by immersing the sintered carbide powder in a metal salt solution or a metal alkoxide solution and drying it as a raw material. Based on the water absorption, each of the above solutions is taken into the fine structure of the baked carbide. As a result, the metal microcrystalline particles in each solution are uniformly dispersed and encased in a number of micropores of the baked carbide. Then, by drying, the metal fine particles become a raw material powder in a state of being uniformly dispersed in the fine structure of the calcined carbide, and the metal fine particles are uniformly dispersed by the current powder being subjected to current sintering. It becomes a metal composite sintered body as a homogeneous catalyst for detoxification. For this reason, the reducing action of the sintered charcoal is uniformly amplified by the metal uniformly dispersed into the fine structure of the sintered charcoal, and the reductive decomposition function as a whole of the pollutant is also the first invention. It will be better than the case.
[0012]
In the case of each of the first and second inventions, the removal of the pollutant by the catalyst as described above does not remove the pollutant chamber from the surrounding atmosphere by adsorbing and storing it like activated carbon, but reducing it. Since it removes pollutants by decomposing, it can be used semi-permanently, there is no need for replacement or disposal, and there is no problem with replacement or disposal. In addition, it is essentially a reductive decomposition of pollutants using the reducing action of sintered charcoal, and it mixes and disperses metals in order to amplify the reducing action. It becomes possible to supply.
[0013]
Such a catalyst of the first and second inventions may be used as it is in the air or in a state exposed to water, but it is filled as a filter layer in the middle of an exhaust duct of a factory, an incinerator or the like, and dioxin, NOx In order to reduce and decompose pollutants, etc., in order to reduce and decompose formaldehyde and ketones generated from residential building materials by filling a filter layer in the middle of the air flow passage of indoor air purifiers, or for large vehicles The exhaust gas is used as an exhaust gas catalyst in the middle of the exhaust pipe to reduce NOx. In addition, what is necessary is just to employ | adopt various forms, such as a desktop type, a wall hanging type, and a hanging type, as an indoor air cleaner. Furthermore, by installing the above catalyst in the middle of water pipes or in a tap water storage tank as it is or in a container that allows water to flow in and out, halogenated organic substances such as trihalomethane contained in water can be removed. It is possible to remove contaminants by reductive decomposition. When used for these applications, the above raw materials are sintered by electric current sintering, so that sintering and molding are performed at the same time, and firing is performed in a high temperature range using a conventional electric furnace. In comparison, a special device for molding becomes unnecessary. Moreover, the sintering can be completed in a significantly shorter time (several minutes) than when the temperature is raised in an electric furnace. In addition, by mixing only the raw material powder without mixing the binder into the mold to form a composite sintered body, a sintering aid such as a binder becomes unnecessary, and it is troublesome and uniform with the binder. Mixing or the like is not necessary, and the decomposition and detoxification catalyst can be obtained more easily.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
<First Embodiment>
FIG. 1 shows an apparatus for producing the decomposition and detoxification catalyst of the present invention by an electric sintering method, wherein 1 is a mold, 2 and 2 are electrode and press punches, and 3 is a mixed powder of raw materials.
[0016]
The mold 1 is formed with a cylindrical hole 1a that opens upward and downward, and the electrode and pressure punches 2 and 2 having an outer diameter substantially the same as the inner diameter of the hole 1a can be relatively moved in the vertical direction from the upper and lower sides. It is designed to be fitted inside. And in the state which filled the mixed powder 3 between the both electrode and press punches 2 and 2 in the said type | mold 1, both the electrode and press punches 2 and 2 are pressed in the arrow direction of FIG. At the same time, a power supply device (not shown) is energized between the electrodes and pressure punches 2 and 2 to form and sinter the mixed powder 3 between the electrodes 2 and 2.
[0017]
The mixed powder 3 is obtained by mixing a fired carbide powder obtained by firing biomass and a metal powder or a metal oxide powder. The above-mentioned calcined carbide powder is obtained by heating calcined charcoal (charcoal) obtained by heat treatment in a low temperature range of approximately 300 ° C. to approximately 800 ° C. in a carbonization furnace not shown in the figure using raw materials such as felled trees and thinned wood as biomass. The powder is adjusted to a predetermined diameter. The metal powder or metal oxide powder is Cu, Al, Ag, Ti, Ni, Li, Si, Fe, Pt, V, Cr, Mn, Co, Zr, Mo, Pd, K, Sn, Any one or two or more metal powders selected from Au, or a metal oxide powder of any one or more of the above metals is used. The mixing ratio of the calcined carbide powder and the metal powder or metal oxide powder is preferably set to 1 to 50 metal powder or metal oxide powder with respect to the calcined carbide powder 100 by weight ratio. Of course, the metal powder or metal oxide powder may be 50 or more by weight. On the other hand, it is preferable to reduce the mixing ratio from the viewpoint of saving / reducing metal powder or metal oxide powder, and the weight ratio is in the range of 1 to 25, 25 to 50, finely in the range of 1 to 10, 11 to 25. It is preferable to set the value of.
[0018]
Then, the mixed powder 3 is filled between the electrode / pressurizing punches 2 and 2 in the mold 1, and the mixed powder 3 is sandwiched between the electrode / pressurizing punches 2 and 2 and pressed. A predetermined current is applied for several minutes. By this energization, first, micro discharge is caused between the particles of the mixed powder 3 to generate plasma on the particle surface, thereby cleaning and activating the particle surface. Continuing on, Joule heat is generated between the particles of the mixed powder 3 by the energization, and the particles are thermally bonded together while firing. As a result, a metal composite sintered body is obtained as a decomposition and detoxification catalyst formed into a predetermined cylindrical shape by the inner peripheral surface of the mold 1 and the front end surfaces of both electrodes and pressure punches 2 and 2.
[0019]
The filling of the mold 1 is preferably performed using only the mixed powder 3 described above, but a sintering aid containing 50% or more of fixed carbon with respect to the mixed powder 3 is about 30% by weight or less. You may make it mix in the range of. Further, the above mixed powder 3 is mixed with other inorganic powders, ceramic powders, etc., and the composite sintered body made of charcoal powder, metal powder, metal oxide powder, inorganic powder, ceramics powder, etc. is decomposed and rendered harmless. You may make it obtain as. Also, in order to change the metal concentration distribution in the thickness direction so that the reductive decomposition function changes in the thickness direction, the mixing ratio of the charcoal powder and other metal powders is changed in the thickness direction. The mold 1 may be filled and subjected to current sintering while being pressed. Furthermore, the space in which the mold 1 for carrying out the above-mentioned current sintering method and the two electrode / pressure punches 2 and 2 are installed may be set to a predetermined negative pressure or vacuum state. Further, it may be performed in an inert gas such as Ar, N2, He, or in the air.
[0020]
FIG. 2 shows a specific apparatus for producing the metal composite sintered charcoal as the decomposition and detoxification catalyst by the electric current sintering method, wherein 11 is a frame, 12 is a die made of graphite, 13a, Reference numeral 13b denotes upper and lower punches inserted into the die 12, reference numerals 14a and 14b denote upper and lower electrodes sandwiching the upper and lower punches 13a and 13b, reference numeral 15 denotes a power source connected to the upper and lower electrodes 14a and 14b, and reference numeral 16 denotes an upper part. A hydraulic cylinder that presses the electrode 14b, 17 is a vacuum chamber in which the die 12, the upper and lower punches 13a and 13b and the upper and lower electrodes 14a and 14b are disposed, and 18 is a vacuum pump for evacuating the vacuum chamber 17 , 19 is a radiation thermometer for measuring the temperature in the die 12 sandwiched between both punches 13a, 13b.
[0021]
As shown in detail in FIG. 3, the die 12 has a cylindrical hole 12a that opens in the vertical direction, and punches 13a and 13b having an outer diameter substantially the same as the inner diameter of the hole 12a. Is fitted in such a manner that it can move in the vertical direction. Then, the vacuum chamber 17 is brought into a predetermined vacuum state by the operation of the vacuum pump 18, and the hydraulic cylinder 16 is operated to press the upper punch 13a through the upper electrode 14a, thereby sintering between the upper and lower punches 13a and 13b. The upper and lower electrodes 14a and 14b are energized from the power source 15 to be sintered while pressurizing the mixed powder 20 (same as the mixed powder 3 described above). The sintering temperature at this time is set to a predetermined temperature while being measured by the radiation thermometer 19.
[0022]
Next, a process for obtaining the above-described decomposition and detoxification catalyst will be described with reference to FIG. Basically, for example, low-temperature firing to obtain a fired carbide (charcoal) by heating and carbonizing a wood-based material such as cedar wood in a carbonization furnace (not shown) in a low temperature range of approximately 300 ° C. to 800 ° C .; Raw material adjustment to obtain a mixed powder 20 by mixing a predetermined amount of the same metal powder or metal oxide powder with the powder adjusted to a predetermined diameter (for example, 20 to 40 mesh) by pulverizing the charcoal, and current sintering ( High temperature firing is performed by sintering in a high temperature range of 800 ° C. to 3000 ° C. to obtain composite sintered charcoal. In the low-temperature firing, smoke generated by the heat treatment in the carbonization furnace is burned by an afterburner to make it pollution-free, and then exhausted. In the high-temperature firing, the charcoal is pulverized into powder of a predetermined diameter, the charcoal powder and the metal powder or metal oxide powder are weighed and uniformly mixed, and a predetermined amount of the mixed powder 20 is obtained. The mold is packed between the upper and lower punches 13a and 13b of the die 12, and then subjected to discharge sintering while applying a predetermined high pressure by the hydraulic cylinder 16 in the vacuum chamber 17 under a predetermined vacuum state. The catalyst for decomposition and detoxification molded into a disk shape or a cylindrical shape is obtained.
[0023]
FIG. 5 shows an example of an indoor air purifier 30 using the catalyst obtained as described above. The air purifier 30 includes a rectangular or cylindrical housing 32 erected on a pedestal 31, a catalyst layer 33 filled in an intermediate position in the vertical direction of the housing 32, and the catalyst layer 33. And a fan 34 for circulating air. .. Are formed in the lower peripheral surface of the housing 32 so as to suck indoor air inside and outside, and on the upper surface, air outlets after passing through the catalyst layer 33 are formed. The fan 34 that is opened facing the upper side and is driven by a motor 37 is disposed at the outlet 36. A support plate 38 having a large number of through holes 38 a is provided at an intermediate position of the housing 32, and the catalyst layer 33 is filled on the support plate 38.
[0024]
When the fan 34 is activated by the operation of the motor 37, indoor air is sucked from the lower suction ports 35, 35,..., And the air passes through the catalyst layer 33 and enters the original chamber from the blower port 36. Returned. When passing through the catalyst layer 33, pollutants in the air, for example, formaldehyde volatilized from the housing building materials are adsorbed and reduced and decomposed by the catalyst layer 33.
[0025]
In such an air purifier, a heating element such as a heater or a heat generation lamp is provided in place of the fan 34 as means for circulating air, and suction from the suction port 35 by air convection and the catalyst layer 33 are performed. You may make it perform the blowing-out from the blowing outlet 36 of the air which passed through.
[0026]
Second Embodiment
In the second embodiment, as a raw material for electric sintering, the powder of the fired carbide in the first embodiment is dipped in a metal salt solution or a metal alkoxide solution and then dried to remove moisture (raw material powders 3 ′, 20 ′) Is used. The second embodiment is different from the first embodiment only in the use of the raw material powders 3 ′ and 20 ′ as described above, and the current sintering apparatus and method are the same as those in the first embodiment. Omitted.
[0027]
The metal salt solution was selected from Cu, Al, Ag, Ti, Ni, Li, Si, Fe, Pt, V, Cr, Mn, Co, Zr, Mo, Pd, K, Sn, and Au. Any one or two or more metals added to nitric acid or nitrate to form a solution may be used. For example, Cu (NO _Three ) ₂ Or Ni (NO _Three ) ₂ And AgNO _Three Is mentioned. Moreover, as said metal alkoxide solution, what is necessary is just to use any 1 type, or 2 or more types of 1-propanol solutions of the metal shown above. For example, Ti (OC _Three H ₇ ) _Four And Fe (C _Five H ₇ O ₂ ) _Three Etc. The higher the concentration of these solutions, the better. However, from the viewpoint of saving and reducing the metal content, it is preferable to lower the concentration, for example, 0.05M (mol) or 0.10M or more. Thus, a metal composite sintered body having sufficiently high conductive performance can be obtained.
[0028]
Then, the raw material powder 3 'is filled between the electrodes and press punches 2 and 2 in the mold 1, and the filled raw material powder 3' is sandwiched between the electrodes and press punches 2 and 2 and added. A predetermined current is applied for several minutes (for example, 5 minutes) while pressing. By this energization, first, a micro discharge is caused between the particles of the raw material powder 3 'to generate plasma on the particle surface, thereby cleaning and activating the particle surface. Continuously, Joule heat is generated between the particles of the raw material powder 3 ′ by the above energization, and the particles are thermally bonded while firing with the heat. As a result, a metal composite sintered body is obtained as a decomposition and detoxification catalyst formed into a predetermined cylindrical shape by the inner peripheral surface of the mold 1 and the front end surfaces of both electrodes and pressure punches 2 and 2.
[0029]
Note that the current sintering method, such as preferably filling the mold 1 with only the raw material powder 3 ', is the same as in the first embodiment.
[0030]
Next, a process for obtaining a decomposition and detoxification catalyst using the above-described substance containing biomass as a starting material using the apparatus of FIG. 2 described in the first embodiment will be described with reference to FIG. Basically, for example, low-temperature firing to obtain a fired carbide (charcoal) by heating and carbonizing a wood-based material such as cedar wood in a carbonization furnace (not shown) in a low temperature range of approximately 300 ° C. to 800 ° C .; The powder adjusted to a predetermined diameter by pulverizing the charcoal is immersed in the above metal salt solution or metal alkoxide solution and then heated and dried to prepare a raw material powder, and by electric current sintering (discharge sintering), 800 ° C. to High temperature firing is performed to obtain a composite sintered body by sintering in a high temperature range of 3000 ° C. In the low-temperature firing, smoke generated by the heat treatment in the carbonization furnace is burned by an afterburner to make it pollution-free, and then exhausted. In the high-temperature firing, the raw material powder 20 ′ (see FIG. 2) is weighed, and a predetermined amount is filled between the upper and lower punches 13 a and 13 b of the die 12, and then the above-mentioned in a vacuum chamber 17 under a predetermined vacuum state. The electric cylinder 16 is subjected to discharge sintering while applying a predetermined high pressure, and is cooled to obtain a metal composite sintered body as a decomposition and detoxification catalyst.
[0031]
【Example】
The following comparative tests were conducted on the reductive decomposition performance for NO in NOx as a pollutant.
[0032]
(Sample used for testing)
As Example 1 according to the first embodiment, cedar wood is heat-treated at a temperature of about 700 ° C. to produce a calcined carbide, which is made into a powder of 20 to 40 mesh to make charcoal powder, while 100 g of this charcoal powder. As a metal oxide powder, Fe ₂ O _Three 25 g of (iron oxide) powder was uniformly mixed to prepare a charcoal / iron oxide mixed powder. Then, only the raw material of this mixed powder is filled in the mold 1, and in order to protect the mold 1, it is sintered for 5 minutes in a vacuum atmosphere of 1 to 0.1 Torr with a pressing force of 49 MPa and made of charcoal / iron oxide. A metal composite sintered body was produced. The sintering temperature at this time was 2500 ° C.
[0033]
As Example 2 according to the second embodiment, 2 g of the same charcoal powder as described above was added to Cu (NO) with a concentration of 0.1 M (mol). _Three ) ₂ After immersing in 50 ml of (copper nitrate) solution, it was dried for 24 hours with a dryer at 105 ° C. to produce a raw material powder. Then, only this raw material powder is filled into the mold 12 and sintered in a vacuum atmosphere of 1 to 0.1 Torr for 5 minutes with a pressure of 49 MPa to protect the mold 12, and the charcoal / copper nitrate metal composite sintering. The body was made. The sintering temperature at that time was 2500 ° C.
[0034]
As Comparative Example 1, cedar wood was heat-treated at a temperature of about 600 ° C. to produce a calcined carbide, which was made into a powder of 20 to 40 mesh to prepare charcoal powder.
[0035]
As Comparative Example 2, 5 g of Charcoal powder in Comparative Example 1 was replaced with Ti (OC _Three H ₇ ) _Four It was immersed in 100 ml of a (titanium alkoxide) solution and then dried at 105 ° C. to prepare a charcoal / titanium oxide composite.
[0036]
(Test method)
The test was performed using a test apparatus as shown in FIG. As a test method, first, a predetermined amount of each of the above four types of samples is individually filled in a reaction tube 42 having open / close valves 41 and 41 at the upstream and downstream ends, respectively. 95 ppm of NO gas is allowed to flow from the side cylinder 43 at a flow rate of 100 ml / min, and N in the outlet gas after passing through the reaction tube 42 in the downstream detection unit 44. ₂ , O ₂ , NO, N ₂ Each concentration of O was analyzed and measured by gas chromatography every predetermined elapsed time. The filling amount of the sample was 1 g in Example 1, 0.645 g in Example 2, 0.5 g in Comparative Example 1, and 1 g in Comparative Example 2.
[0037]
(Test results)
Table 1 shows the case of Example 1, Table 2 shows the case of Example 2, Table 3 shows the case of Comparative Example 1, and Table 4 shows the case of Comparative Example 2.
[0038]
[Table 1]

[0039]
[Table 2]

[0040]
[Table 3]

[0041]
[Table 4]

[0042]
First, when comparing Comparative Example 1 with Examples 1 and 2, in the case of Comparative Example 1 with only charcoal powder, the NO gas concentration of 95 ppm put in the reaction tube 42 is the outlet gas concentration after passing through the reaction tube 42. It was 38 to 39 ppm, which was considerably lower than the outlet gas concentration of Examples 1 and 2 of 46 to 49 ppm. This is considered to be due to the strong adsorption effect in the case of Comparative Example 1 with only charcoal before sintering, and NO being more strongly adsorbed by the adsorption action. On the other hand, in the case of Comparative Example 1, N ₂ The concentration decreases in the range of 630 to 750 ppm with time, and O ₂ Concentration is zero, N ₂ The O concentration was 1.1 to 1.3 ppm, whereas in Examples 1 and 2, N ₂ Concentration shows an increasing tendency with time in the range of 1080 to 1700 ppm. ₂ The concentration is 10-70 ppm, NO concentration The concentration is significantly higher than that of Comparative Example 1, such as 46 to 49 ppm. That is, NO flowing through the reaction tube 42 is N ₂ , O ₂ , N ₂ It is considered that each of them was reductively decomposed into O. Therefore, Examples 1 and 2 are considered to be superior in NO reductive decomposition ability as compared with Comparative Example 1.
[0043]
Next, a comparison between Comparative Example 2 and Examples 1 and 2 shows that in the case of Comparative Example 2 of the charcoal / titanium oxide composite, a 95 ppm NO concentration in the reaction tube 42 is passed through the reaction tube 42. The outlet gas concentration was 41 to 42 ppm, which was slightly lower than the outlet gas concentrations of Examples 1 and 2 of 46 to 49 ppm. On the other hand, in the case of Comparative Example 2, N ₂ Concentration ranges from 750 to 1030 ppm, O ₂ Concentration is 10-30ppm, N ₂ The O concentration was 2.1 to 2.4 ppm, whereas in Examples 1 and 2, N ₂ Concentration shows an increasing tendency with time in the range of 1080 to 1700 ppm. ₂ The concentration is 10-70 ppm, NO concentration The concentration is equal to or higher than that of Comparative Example 2, such as 46 to 49 ppm. Therefore, the NO flowing through the reaction tube 42 is changed to N ₂ , O ₂ , N ₂ Examples 1 and 2 are considered to be at least equivalent to or superior to Comparative Example 2 in which titanium oxide as a photocatalyst is mixed in the ability to reduce and decompose O into O.
[0044]
【The invention's effect】
As explained above, the catalyst for detoxification of pollutants in the first invention according to any one of claims 1, 2, 6 to 8, or the second according to any one of claims 3 to 8. According to the catalyst for detoxification of pollutants in the invention of the present invention, the reduction action is achieved by sintering the burned carbide obtained by baking the biomass-containing substance at a higher temperature. Is amplified by the metal contained in the raw material for sintering. By contacting the detoxification catalyst with air or water containing the pollutant, the pollutant is slightly adsorbed by the sintered charcoal. While adsorbed by the action, the adsorbed pollutant or the contacting pollutant can be reduced and decomposed by the reducing action. At this time, if the metal to be contained is dried as a raw material after immersing the sintered carbide powder in a metal salt solution or a metal alkoxide solution as in the second aspect of the invention, the reduction of the sintered charcoal The action is uniformly amplified by the metal uniformly dispersed in the fine structure of the sintered coal, and the reductive decomposition function as a whole of the pollutant is also improved as compared with the case of the first invention. .
[0045]
In each of the first and second inventions, the removal of the pollutant by the catalyst does not remove the pollutant chamber from the surrounding atmosphere by adsorbing and storing like activated carbon, but by reducing and decomposing. Since it removes pollutants, it can be used semi-permanently, and there is no need for replacement or disposal, and there are no problems associated with replacement or disposal. In addition, it is essentially a reductive decomposition of pollutants using the reducing action of sintered charcoal, and it mixes and disperses metals in order to amplify the reducing action. Will be able to supply. In addition, since the above raw materials are sintered by electric current sintering, the sintering and molding are performed at the same time, and the molding is performed compared with the case of firing at a high temperature range using a conventional electric furnace. In addition to eliminating the need for special equipment, sintering can be completed in a much shorter time (several minutes) than when raising the temperature in an electric furnace, making it easier to provide a catalyst for detoxification. Will be able to.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view showing the principle of electric current sintering of the present invention.
FIG. 2 is a schematic view showing an apparatus for current sintering.
FIG. 3 is a partial cross-sectional perspective view showing a mold and raw material powder for electric current sintering.
FIG. 4 is a flowchart showing a procedure of the manufacturing method according to the first embodiment.
FIG. 5 is a cross-sectional explanatory view of an air purifier as an example of use of a catalyst.
FIG. 6 is a flowchart showing a procedure of a manufacturing method according to the second embodiment.
FIG. 7 is a schematic diagram showing a test apparatus.
[Explanation of symbols]
3,20 Mixed powder (raw material powder)
3 ', 20' raw material powder

Claims (8)

Powdered particles using a powder mixture of metal powder or metal oxide powder mixed with a powder of fired carbide obtained by firing a material containing biomass as a raw material, and pressurizing the raw material in a mold A catalyst for detoxification of pollutants, characterized in that it is obtained by discharging and sintering between them. In claim 1,
Metal powder or metal oxide powder
Cu, Al, Ag, Ti, Ni, Li, Si, Fe, Pt, V, Cr, Mn,
It is a powder of one or more metals selected from Co, Zr, Mo, Pd, K, Sn, and Au, or a metal oxide powder of one or more metals described above. A catalyst for detoxification of pollutants. A state in which a fired carbide powder obtained by firing a material containing biomass is immersed in either a metal salt solution or a metal alkoxide solution and then dried, and this material is filled in a mold. A catalyst for decomposing and detoxifying pollutants, characterized in that the catalyst is obtained by discharging between powder particles while sintering and sintering. In claim 3,
A catalyst for detoxification of pollutants, wherein the metal salt solution is a solution of any one of nitrates or sulfates of Cu, Ni, Fe, Ag, and Ti. In claim 3,
The metal alkoxide solution is a 1-propanol solution of any one of Cu, Ni, Fe, Ag, and Ti. In claim 1 or claim 3,
A catalyst for degrading and detoxifying pollutants, wherein the substance containing biomass is a substance containing cellulose. In claim 1 or claim 3,
A calcined carbide is a calcined catalyst for decomposing and detoxifying pollutants, characterized by being calcined in a temperature range from 300 ° C to 800 ° C. In claim 1 or claim 3,
A catalyst for decomposing and detoxifying a pollutant, characterized in that pressurization and discharge are performed in a reduced pressure state on a powder raw material filled in a mold and sintered.

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