JP6540990B2 - Aldehyde removal material using Ru (fcc) support - Google Patents

Description

  The present invention relates to an aldehydes removing material using a Ru (fcc) support.

  Conventionally, various adsorbents have been studied for the purpose of removing acetaldehyde, which is the main component of tobacco odor in the interior of buildings and in cars and the like, or formaldehyde, which is known as a causative agent of sick house syndrome. ing.

  Among them, activated carbon is known as a material that adsorbs VOC (volatile organic compounds) and the like, but it is considered difficult to remove low molecular weight and highly polar organic matter (for example, acetaldehyde, formaldehyde and the like). Then, when using for the said use, it is known to make an activated carbon carry | support amines and to improve adsorption performance (patent document 1).

  However, since the above-described amine-supporting technology is unstable in the state of the supported amines, it is likely to be deactivated by thermal and time-dependent chemical changes, and maintain high removal performance in the long run. There is a problem that is difficult.

  On the other hand, a method using an oxidation catalyst has attracted attention in recent years for the purpose of removing VOCs. Examples of the oxidation catalyst include activated carbon and alumina supporting platinum (Patent Document 2, Non-Patent Document 1). Such platinum-supported oxidation catalysts are highly active and show high performance for removal of aldehydes. However, precious metals such as platinum are expensive, and the use of less expensive catalysts or metals is now required.

  Ruthenium (Ru) has come to be used as a platinum substitute. Ru is less expensive than platinum etc. and is known to be active as an oxidation catalyst, but usually it needs to be used at high temperature to get the activity of ruthenium having a hexagonal close-packed structure (hcp) It will come.

Japanese Patent Application Laid-Open No. 56-53744 JP, 2006-68591, A

Applied Catalysis B: Environmental, 1996, 8, pp. 405-415

  The object of the present invention is to provide an aldehydes removing material using a Ru carrier capable of efficiently removing aldehydes at a temperature lower than a ruthenium particle carrier having a hexagonal close-packed structure (hcp).

As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention is as follows.
1. A material for removing aldehydes, characterized in that a Ru (fcc) support composed of Ru (fcc) particles having a face-centered cubic lattice structure and a carrier is used.
2. The aldehydes-removing material according to the above 1, wherein the support is a support selected from the group consisting of activated carbon, activated carbon fibers, alumina, silica, zeolite, composite oxides and porous metal complexes.

  The aldehyde removing material according to the present invention usually takes a hexagonal close-packed structure (hcp) because it uses a Ru (fcc) support composed of Ru (fcc) particles having a face-centered cubic lattice structure and a carrier. Aldehydes can be efficiently removed at a temperature lower than that of the Ru (hcp) support.

3 is a TEM image of Ru (fcc) particles of Example 1. 5 is a powder X-ray diffraction chart of Ru (fcc) particles of Example 1. FIG. 7 is a TEM image of Ru (hcp) particles of Comparative Example 1; 5 is a powder X-ray diffraction chart of Ru (hcp) particles of Comparative Example 1;

Hereinafter, the present invention will be described in detail.
The aldehyde removal material of the present invention is characterized by using a Ru (fcc) support composed of Ru (fcc) particles having a face-centered cubic lattice structure and a carrier.

  Ruthenium particles usually take a hexagonal close-packed structure (hcp). Although the temperature for achieving activity is high in this Ru (hcp) particle, the Ru (fcc) particle having a face-centered cubic lattice structure of the present invention exhibits a good aldehyde removal rate even at 80 ° C. The Ru (fcc) particles can be synthesized by using tris (acetylacetonato) ruthenium (III) as a raw material. When a ruthenium salt such as ruthenium (III) chloride is used as a raw material, Ru (hcp) particles having a hexagonal close-packed structure are obtained, and Ru (fcc) particles having a face-centered cubic lattice structure are not obtained. The hexagonal close-packed structure (hcp) or face-centered cubic lattice structure (fcc) can be analyzed by powder X-ray diffraction.

  Carriers used in the present invention include activated carbon, activated carbon fibers (ACF), alumina, silica, zeolites, composite oxides, porous metal complexes (also referred to as Porous Coordination Polymers or Metal Organic Frameworks), etc. Be The composite oxide is preferably a composite oxide containing cerium, and examples thereof include ceria-zirconia composite oxide and the like.

  The method for supporting Ru (fcc) particles on a carrier is not particularly limited as long as the desired properties can be obtained. For example, Ru (fcc) is coated with a protective agent such as polyvinyl pyrrolidone (PVP) while the particles are coated. Ru (fcc) nanoparticles are synthesized first by reduction treatment of Ru ions in tris (acetylacetonato) ruthenium (III), which is a precursor of nanoparticles, in a reducing solvent, and Ru (fcc) is post-processed. The carrier is added to a solvent in which particles are dispersed, and the solvent is evaporated to dryness. Also, Ru ions in tris (acetylacetonato) ruthenium (III), which is a precursor of Ru (fcc) nanoparticles, and a carrier supporting the same coexist in a reducing solvent, and the Ru ions are also subjected to reduction treatment. is there. As a reducing solvent, triethylene glycol is preferable, and reduction by heating at 150 to 250 ° C. for several hours is preferable. The former evaporation to dryness method can be used for all carriers except when the carrier has weak affinity with the protective agent. For supports with small pore size (for example, activated carbon fiber, porous metal complex, etc.), it is conceivable that the pore size is smaller than the Ru particle size, so the latter method of reducing Ru ions in the presence of the carrier is preferable . The resulting Ru (fcc) nanoparticles will be approximately 3 to 5 nm.

  As the amount of Ru supported on the carrier, it is preferable to adjust the amount of Ru particles and the concentration of Ru ions so that the Ru particles are supported at 0.1 to 10% by mass with respect to the carrier. More preferably, it is 1 to 5% by mass. If the amount is more than 10% by mass, the metal concentration with respect to the carrier is too high, so the carrier is supported, but it is difficult to be supported in a highly dispersed state, which is not preferable.

  Hereinafter, the present invention will be more specifically described by way of examples. The present invention is not limited by the following examples, and it is of course possible to implement with appropriate modifications as long as it can conform to the above-mentioned and the following effects, and all of them can be technical of the present invention. It is included in the scope. In addition, the evaluation in an Example and a comparative example was performed as follows.

<Powder X-ray diffraction measurement>
The obtained particles were measured by a symmetrical reflection method using a powder X-ray diffractometer ("NEW D8 ADVANCE" manufactured by Bruker AXS Co., Ltd.) The measurement conditions are shown below.
1) X-ray source: CuKα (λ = 1.5418 Å) 40 kV 200 mA
2) Goniometer: Vertical goniometer 3) Detector: Scintillation counter 4) Diffraction angle (2θ) range: 3 to 90 °
5) Scanning step: 0.05 °
6) Integration time: 0.5 sec / step 7) Slit: divergence slit = 0.5 °, light receiving slit = 0.15 mm, scattering slit = 0.5 °

<Transmission electron microscope (TEM) observation>
The obtained Ru particles were observed using a transmission electron microscope (“HT7700” manufactured by Hitachi, Ltd. or “JEM-2200FS” manufactured by JEOL Ltd.).

<Aldehyde gas flow system adsorption test>
0.229 cc of Ru carrier was packed into the column, and the test gas was circulated at 0.2 L / min. The gas concentration at the inlet / outlet of the sample was measured using a Form Aldemeter htV (JMS Co., Ltd.), and the removal rate was calculated from the ratio. Specifically, first, measurement was started under an atmosphere of 25 ° C., and after one hour, the gas concentration at the inlet / outlet was measured to calculate the removal rate. Subsequently, the gas was placed under an atmosphere of 80 ° C., and after one hour, the gas concentration at the inlet and outlet was measured to calculate the removal rate. A total of 2 hours of measurement was performed. Details of the evaluation conditions are shown below.
1) Measurement atmosphere: 25 ° C. or 80 ° C. 2) Pressure: normal pressure 3) Test gas composition: Formaldehyde concentration 3 ppm (25 ° C., 50% RH air dilution)
4) Space velocity: 570,000 hr ^-1
5) Average particle size (particle size of measurement sample): 355 to 500 μm

Example 1
1.63 g (4.2 mmol) of tris (acetylacetonato) ruthenium (III) and 0.222 g (2.0 mmol) of polyvinylpyrrolidone as a protecting agent are placed in 50 ml of triethylene glycol as a reducing solvent, and 200 After heating at 3 ° C. for 3 hours, Ru (fcc) particles having a face-centered cubic lattice structure were synthesized. The TEM image is shown in FIG. 1, and the powder X-ray diffraction chart is shown in FIG. It was confirmed from the TEM image of FIG. 1 that particles of about 4.1 nm to 4.6 nm were formed. Further, it was confirmed from the powder X-ray diffraction chart that Ru (fcc) particles having a face-centered cubic lattice structure were synthesized.
Next, 15 mg of Ru (fcc) particles synthesized above were dispersed in 30 ml of distilled water, and 1 g of γ-alumina which had been heat treated in air at 700 ° C. for 5 hours was added thereto beforehand and stirred at room temperature for 1 day. The suspension was concentrated to dryness under vacuum at 60 ° C. to obtain 1 mass% Ru (fcc) -supported γ-alumina. The particle diameter was adjusted to 355 to 500 μm by pressing with a press and classification with a sieve. Thereafter, an aldehyde-based gas flow system adsorption test was conducted. The results are shown in Table 1.

Comparative Example 1
Put 1.098 g (4.2 mmol) of ruthenium chloride and 0.222 g (2.0 mmol) of polyvinylpyrrolidone as a protecting agent into 50 ml of triethylene glycol as a reducing solvent, and heat at 200 ° C. for 3 hours while stirring, Ru (hcp) particles with close packed structure were synthesized. The TEM image is shown in FIG. 3, and the powder X-ray diffraction chart is shown in FIG. It was confirmed from the TEM image of FIG. 3 that particles of about 3.5 nm to 4.5 nm were formed. In addition, it was confirmed from the powder X-ray diffraction chart that Ru (hcp) particles having a hexagonal close-packed structure were synthesized.
Next, 15 mg of Ru (hcp) particles synthesized above were dispersed in 30 ml of distilled water, and 1 g of γ-alumina which had been heat-treated in air at 700 ° C. for 5 hours was added thereto beforehand and stirred at room temperature for 1 day. The suspension was concentrated to dryness under vacuum at 60 ° C. to obtain 1 mass% Ru (hcp) -supported γ-alumina. The particle size was adjusted to 355-500 μm by pressing with a press and classification with a sieve. Thereafter, an aldehyde-based gas flow system adsorption test was conducted. The results are shown in Table 1.

  As is clear from Table 1, in Example 1 using a support on which Ru (fcc) particles are supported, the formaldehyde removal rate at 80 ° C. is as high as 44%. The utility of the present invention is evident from Comparative Example 1 because a removal rate of 40% or more can not be achieved unless the temperature is raised.

  Since the aldehydes removal material of the present invention is excellent in the effect of removing aldehydes indoors and in the car, it can provide a more comfortable space and reduce diseases such as sick house syndrome. In addition, since a Ru (fcc) support having a face-centered cubic lattice structure is used, it is cheaper than a Pt-based catalyst, and it can be greatly contributed to the industrial world.

Claims (2)

  A material for removing aldehydes characterized by using a Ru (fcc) support composed of Ru (fcc) particles of a face-centered cubic lattice structure and a carrier.   The material for removing aldehydes according to claim 1, wherein the support is a support selected from the group consisting of activated carbon, activated carbon fibers, alumina, silica, zeolite, composite oxides and porous metal complexes.