JPH02160021A - Deodorizing method with photocatalyst - Google Patents

Abstract

PURPOSE:To effectively deodorize malodorous substances in gas with a photocatalyst and to maintain the performance of the photocatalyst over a long period of time by passing the gas through an aq. suspension of the photocatalyst and irradiating the photocatalyst with UV. CONSTITUTION:A reaction vessel 1 is filled with a uniform aq. suspension of a photocatalyst 4 such as titanium oxide or yttrium oxide. Gas contg. malodorous substances is sucked from an inlet 6 and brought into contact with the photocatalyst 4 irradiated with UV from light sources 2 during passing through the vessel 1. Oxidation decomposition is caused and the malodorous substances are deodorized. Even when high molecular substances such as nicotine and alkaloid coexist with the malodorous substances, the malodorous substances are effectively deodorized and the performance of the photocatalyst is maintained over a long period of time.

Description

[Detailed description of the invention] Industrial applications This invention prevents bad odors (cooking utensils) in homes and offices.

The present invention relates to a method for deodorizing food utensils, tobacco odor, body odor, pet odor, toilet odor, etc.).

Conventional technology The components of bad odors that occur in homes and offices (cooking utensils, food hanging utensils, tobacco odors, body odors, pet and toilet odors, etc.) are as follows:
Nitrogen compounds (ammonia, amines, indole, skatole, etc.), sulfur compounds (hydrogen sulfide, methyl mercaptan, methyl sulfide.

methyl disulfide, dimethyl disulfide, etc.), aldehydes (
There are a wide variety of substances, including formaldehyde, acetaldehyde, etc.), ketones (acetone, etc.), alcohols (methanol, ethanol, etc.), fatty acids, and aromatic compounds.

Conventionally, methods for deodorizing such bad odors include a method of causing a chemical reaction between the malodorous substance and a drug, a method of masking the malodorous substance with an aromatic agent, a method of adsorbing the malodorous substance with activated carbon or zeolite, etc. There were methods that used a combination of methods.

As mentioned above, various deodorizing methods are used, but it is almost impossible to regenerate both the chemicals that cause chemical reactions and the fragrances that mask bad odors after they react with the bad odors. Further, in the case of an adsorbent, when the adsorption capacity is saturated, the deodorizing performance decreases significantly. Therefore, in any case, it is necessary to periodically replace it with a new one.

As a deodorizing method that greatly reduces the frequency of such troublesome operations or eliminates the need for these operations, a photocatalytic method is used that irradiates a semiconductor such as titanium oxide with ultraviolet rays, and the excited semiconductor oxidizes and decomposes organic matter. Attempts are being made to use it.

One of the conventional examples is shown in FIGS. 3 and 4.

FIG. 3 is a perspective view of a conventional deodorizing device, and FIG. 4 is a perspective view of a main part of the reaction chamber shown in FIG. 3.

In the figure, 8 is a base, 9 is an electric lamp that can generate ultraviolet rays,
13 is a reaction chamber, 10a to 10e are guide fins, 11 is a blower, and 12 is a cover. Guide fin 1 of reaction chamber 13
0 is provided with a semiconductor layer. This semiconductor layer is made by supporting a semiconductor catalyst on ceramic paper, a metal plate, or the like.

Problems to be Solved by the Invention The deodorizing method using a photocatalyst as described above can: - effectively deodorize acetaldehydes and other malodorous substances that are difficult to deodorize with the commonly used activated carbon; It has become possible to maintain its performance for a long period of time.

However, bad odors generated in homes and offices are caused by gas components as well as polymeric substances contained in cigarette smoke, such as cochin, other alkaloids, phenols, etc.
Hydrocarbons, etc.) exist as a mixture of D6. Although many of these polymeric substances do not emit bad odors, they adhere to and cover the surface of the metal oxide that is the catalyst that causes the photocatalytic reaction, making it impossible to irradiate the catalyst with ultraviolet rays and causing the catalyst to deteriorate. It becomes difficult to receive energy and the pre-catalytic reaction is reduced, causing reaction deterioration.

The purpose of the present invention is to allow the photocatalytic reaction to continue without polymeric substances or dust adhering to the substance that causes the photocatalytic reaction, and to also decompose the polymeric substance by the photocatalytic reaction and convert it into a low-molecular substance. .

Means for Solving the Problems In order to achieve the above object, the deodorizing method using a photocatalyst of the present invention involves irradiating the photocatalyst with ultraviolet rays while passing a gas containing a malodorous substance through an aqueous solution in which a photocatalyst is uniformly suspended. It is something to do.

The inventors are currently researching the decomposition and deodorization of malodors through photocatalytic reactions; , hydrocarbons, etc.) and dust adhere to the catalyst surface, blocking ultraviolet irradiation, resulting in deterioration of the photocatalytic reaction. In the present invention, water-soluble substances among the above-mentioned polymeric substances are dissolved in water, and insoluble substances pass through the water while remaining in a gaseous state, so that the catalyst surface is not covered and is irradiated with ultraviolet rays. The photocatalytic reaction proceeds without being blocked. Furthermore, polymer substances dissolved in water remain in the water and spend more time contacting the catalyst, so they are more likely to be decomposed by photocatalytic reactions, and if they are reduced to lower molecular weight, gasified, and released to the outside. It can be estimated.

Therefore, the aqueous solution in which the photocatalyst is suspended can maintain a stable state for a long time.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In Figure 1, 1 is a reaction tank, 2 is a light source that emits ultraviolet rays, 3 is an aluminum reflector, 4 is an aqueous solution in which a photocatalyst is suspended, 5 is a pump that sucks out bad smells, and 6 is a gas containing bad smells. , and 7 is the outlet for the purified gas.

Reaction tank 1 is width 1Q0111 x depth 50m + 1 x height 2
Made of 00 aluminum, two light irradiation surfaces are 80H x 180 mm x thickness 2. It is fitted with Ojll's fused quartz plate 8.

Photocatalysts include semiconductor metal oxides such as titanium oxide, yttrium oxide, tin oxide, zinc oxide, and tungsten oxide, and those in which a conductive material such as platinum, palladium, or rhodium is supported on these metal oxides.

Here, titanium oxide, yttrium oxide, and tin oxide with particle diameters on the order of 0.1 micron were used.

The amount of catalyst used was 1 g, which was suspended in 900 ml of distilled water and stirred using a magnetic stirrer 9 and a stirrer 10 so as not to precipitate during the reaction.

The light source 2 may be anything that can emit ultraviolet rays, and the ultraviolet rays may be far ultraviolet rays or near ultraviolet rays. Examples of such light sources include low-pressure mercury lamps, high-pressure mercury lamps, and ultra-high-pressure mercury lamps.Here, we use a 10W germicidal lamp (manufactured by Sankyo Denki, main wavelength 254nm, GL-1O, ultraviolet output 1.9W), which is a low-pressure mercury lamp. 15111 from the side of the quartz plate 8
It was installed and used at a distance of

In the above configuration, the bad odor is sucked into the reaction tank 1 from the inlet 6 using the suction pump 5 at a speed of 1017 m2, and brought into contact with the catalyst 4 in the reaction tank excited by ultraviolet rays generated by the light source 2. , oxidatively decomposes on its surface. The deodorized gas is then released from the outlet lower.

First, place the parts other than the pump of the deodorizing device of the above example in a sealed 10 ol box, extend the outlet of the reaction tank 1 with a hose, connect it to the pump installed outside and operate it, and the hose coming out from the pump put it back into the box. Burn 1 cigarette (Seven Star) in the box for 60
After leaving it for a minute, sample the air inside the sealed box.

The air was sampled by six panelists and the odor concentration was measured using a three-point comparison odor detection method. This operation was repeated six times to observe changes in the deodorizing performance of the present invention.

Compare the above operations under the conditions shown in Table 1 and compare the results in the second table.
As shown in the figure. The catalysts used in Comparative Examples 1 and 2 were metal oxides supported at a ratio of 30,097 m2 on a ceramic paper with a diameter of 68.3 mm, which was placed in a 10Ol sealed box as in the example, and sterilized at 1oW. Light (manufactured by Sankyo Electric, main wavelength 254 m.

Cigarettes were burned while being irradiated with two GL-1o (UV output: 1.8 W), and the odor intensity was measured 60 minutes later.

In this case, a fan is installed in 1 ool of air to stir the gas in the space. Comparative Example 3 is a case in which ultraviolet rays are not irradiated in the same manner as in the example, and Comparative Example 4 is a case in which the metal oxide is not suspended.

The horizontal axis of FIG. 2 is the number of cigarettes burned, and the vertical axis is the odor concentration of the remaining cigarettes measured by the three-point comparative odor detection method.

Effects of the Invention The deodorizing method of the present invention prevents deterioration of the photocatalytic reaction caused by the polymeric substances conventionally contained together with malodorous substances such as cigarette smoke, and can withstand long-term use.

Further, the present invention is excellent not only in preventing deterioration of the catalyst but also in improving the efficiency of the photocatalytic reaction. In other words, water-soluble substances, lower amines, lower fatty acids, etc. in malodorous substances dissolve in water and become concentrated, increasing the residence time in the photocatalytic reaction system and making the photocatalytic reaction more efficient. be.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a deodorizing device using a photocatalyst according to the present embodiment, FIG. 2 is a diagram showing deterioration due to cigarette smoke, and FIG. 3 is a perspective view of a conventional deodorizing device using a photocatalyst. FIG. 4 is a perspective view of the main part of FIG. 3. 1...Reaction tank, 2...Light source, 4...
...Aqueous solution containing photocatalyst, 5...Suction pump. Name of agent: Patent attorney Shigetaka Awano and 1 other person 0
q 1・-Repulsion 1 5-411th shift. Figure <A) ``Ding ゛ grind 2 te 7'57'; + τ° Otofujo (α) Figure Figure

Claims (1)

[Claims] A deodorizing method using a photocatalyst, in which a gas containing a malodorous substance is passed through an aqueous solution in which a photocatalyst is uniformly suspended, and the photocatalyst is irradiated with ultraviolet rays.