JPH0429718A - Ozone treatment method - Google Patents

Abstract

PURPOSE:To stabilize the generation efficiency of ozone and to perform long- term treatment by preliminarily bringing gas to be treated and/or the atmosphere into contact with an acid supported adsorbent before passing the same through an ozone generating electrode. CONSTITUTION:Gas 1 to be treated is divided into two gaseous streams and one of them is sucked by an air pump 2 to be brought into contact with an acid supported adsorbent 3. The acid supported adsorbent 3 is formed by supporting inorg. acid such as sulfuric acid or org. acid such as oxalic acid on active carbon or clay mineral. Next, the gaseous stream enters an ozone generator 4 to become ozonized gas 5 which is, in turn, added to the remaining gas stream to be treated and both gases are sucked by a fan 7 to be mixed at high speed in an impeller part, and brought into contact with an inorg. catalyst 8 such as active carbon or titania to be discharged as treated gas 9. As the gas sucked by the air pump 2, the atmosphere may be used. By this method, efficient deodorizing or sterilization can be carried out for a long period of time and, further, even unreacted ozone is decomposed to oxygen on the surface of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an ozone treatment method. More specifically, the ozone oxidizing power can be used to efficiently deodorize, sterilize, and preserve freshness in the atmosphere of food factories, food storage facilities, pharmaceutical factories, animal breeding rooms, hospitals, homes, vehicle interiors, clean rooms, etc. It's about how to do it.

(b) Conventional technology Methods for deodorizing and sterilizing using ozone have been known for a long time, and various specific methods and devices have been proposed (for example, JP-A-54-119371, 62 -5
7557, 63-59961).

However, with these methods, ozone has an effect on the human body and animals, the operation is complicated, the equipment is large, the processing takes time, and the deodorization and
Due to various problems such as poor sterilization efficiency.

Second, a silent discharge type ozone generating electrode is used as an ozone generator, and a part of air or the gas to be treated is introduced into this to generate ozonized gas, and this ozonized gas is mixed with the waste to be treated. In this treatment method, the ozone-generating ability of the ozone-generating electrode decreases over time, and as a result, the deodorizing and sterilizing effects do not last long.

(c) Problems to be solved by the invention The present invention efficiently performs processes such as deodorization, sterilization, and freshness preservation over a long period of time, and efficiently decomposes ozone that is harmful to the human body, animals, food, etc. This is an attempt to provide a processing method that can do the same.

It is well known that when mixing ozonized gas with the gas to be treated, the gas to be added must be passed through an activated carbon filter, acid-impregnated carbon, solid acid adsorbent layer, etc. 56-130209, 57207593
, 5g-1, 21955, etc.).

However, it is not known that the raw material gas (air or part of the gas to be treated) itself, which is passed through an ozone generating electrode to generate ozonized gas, is subjected to pretreatment.

(d) First means for solving the problem According to the present invention, a part of the gas to be treated and/or the atmosphere is brought into contact with an acid-carrying adsorbent and then passed through an ozone generating electrode of a silent discharge type. An ozone treatment method characterized by generating ozone, mixing the ozonized gas with the remaining gas to be treated, and subsequently treating the gas by bringing it into contact with an inorganic catalyst capable of promoting ozone treatment. provided.

In the present invention, a raw material gas for generating ozone with an ozone generating electrode, that is, a part of the gas to be treated and/or air,
This is based on the discovery that by contacting the product with an acid-supported adsorbent in advance, the decline in ozone generation efficiency over time is significantly suppressed, and as a result, deodorization, sterilization, or freshness preservation treatment can be performed for a long period of time. .

According to the present invention, ozone generation efficiency is stabilized by bringing a part of the gas to be treated and/or air into contact with an acid-supported adsorbent and allowing the gas to flow through the ozone generation electrode. In addition, the ozonized gas obtained in this way is mixed with the gas to be treated, so that the ozone molecules, the components to be ozonated in the gas to be treated, bacteria, etc. are uniformly mixed, and the gas phase This allows the rain sound to respond more efficiently. Furthermore, by continuously bringing this mixed gas into contact with a specific inorganic catalyst, ozone molecules, components to be treated, bacteria, etc. react efficiently on the catalyst surface, and at the same time, unreacted residual ozone can be completely decomposed. .

In the present invention, as the raw material gas for obtaining the ozonized gas, in addition to the gas to be treated, the atmosphere or fresh air may be used as described above. Atmospheric air or fresh air generally contains a smaller amount of impurities than the gas to be treated, and is a more preferable gas for stabilizing the ozone generation efficiency. It is one of the features of the present invention that good results can be obtained even when the method is used.

Examples of the acid-supported adsorbent used in the present invention include inorganic acids such as sulfuric acid and phosphoric acid;
Organic acids such as malic acid are combined with activated carbon (BET specific surface area 2
00 to 2500 m 2/9), or supported on clay minerals (including fired clay) such as allophane, diatomaceous earth, shale, zeolite, sepiolite, activated clay, and a mixture of activated carbon and these clay minerals.

Examples of the shape of the acid-supported adsorbent include pellets, granules, porous plates, plates, macaroni shapes, honeycomb shapes, and fibrous shapes, with granules, honeycomb shapes, and fibrous shapes being particularly preferred.

A suitable amount of acid supported on the adsorbent is 2 to 50 wt%.
5-40vt% is preferable.

In particular, sulfuric acid, phosphoric acid or citric acid with a specific surface area of 500~
2001) m'/9 pellet-shaped, honeycomb-shaped, or fibrous activated carbon (containing a mixture of activated carbon and clay minerals) is most preferably supported in an amount of 5 to 40 wt%.

Methods for carrying acid include a method of spraying an acid aqueous solution onto the adsorbent, a method of impregnating the adsorbent by soaking it in an acid aqueous solution,
When activated carbon and clay minerals are used as adsorbents, examples include a method of kneading an aqueous acid solution and supporting the adsorbent before molding. After supporting, dry as necessary.

The temperature at which a part of the gas to be treated is brought into contact with the acid-supported adsorbent is 0 to 1009C1, preferably 5 to 80C, and the space velocity of the gas to be treated relative to the acid-supported adsorbent is 100 to 500C.
0OOhr”, preferably 500-100,000
hr”.

Various trace components of the gas to be treated are removed by contacting a portion of the gas and/or the atmosphere with an acid-supported adsorbent. In particular, ammonia, amines, etc. that exhibit basicity are selectively removed, suppressing the production of nitrate as a by-product on the surface of the ozone generating electrode, and it is thought that the ozone generation efficiency can be stabilized.

Prior to bringing a part of the gas to be treated and/or the atmosphere into contact with the acid-supported adsorbent, activated carbon (specific surface area: 500~
3000m'/I? ) to previously remove trace amounts of multiple components such as hydrocarbons, aldehydes, carboxylic acids, and sulfur compounds in the gas to be treated is important in further improving ozone generation efficiency.

According to the present invention, when the ozonized gas obtained as described above is mixed with the gas to be treated, it is preferable to use a high-speed rotation means using an impeller such as a blowing fan, and this method is simple and economical. Here, high speed rotation means the rotation speed of the impeller part of the fan of 200 times/minute or more, especially 200 to 15,000 times/minute.
0 times/min is suitable, 500-10,000 times/min is preferred, and 1,000-7,000 times/min is most preferred. The gas space velocity at the impeller rotating part (passing gas amount/inner volume of the impeller rotating part) is 2,00
It is suitable to set it as 0-3,000,000h r-', 5.000-L500,0OOh r-' is preferable, and 10',000-l,000,000h r-
' is most preferable. It is suitable to select the gas temperature during this mixing process in the range of 0 to 150°C.
The temperature is preferably 2 to 100°C, most preferably 5 to 80°C.

Furthermore, according to the present invention, in one preferred embodiment, when the mono-ozonized gas obtained as described above is mixed with the gas to be treated, the treatment is carried out through water or hydrogen peroxide solution. be. According to this aspect, components in the gas to be treated that are difficult to be oxidized by ozone can be efficiently removed, and the oxidizing effect of ozone can also be synergistically improved, which is preferable in terms of improving the treatment effect of ozone. In addition, at this time, the hydrogen peroxide solution used is H, OJ 1 degree of 10
ppm or more is suitable, preferably 50 to 50,
OOOppm.

More preferably, it is 100 to 10,000 ppm.

Another feature of this invention is that after the ozonized gas and the gas to be treated are mixed as described above, they are subsequently brought into contact with an inorganic catalyst.

The inorganic catalyst is not particularly limited as long as it promotes ozone treatment such as deodorization, sterilization, and freshness preservation in the presence of ozone on its surface.

Specific examples include activated carbon, alumina, glue, cordierite, sepiolite, zeolite, other clay minerals, titania, zirconia, magnenoir, iron oxide, copper oxide, manganese oxide, cobalt oxide, etc. and mixtures thereof. Further, an alkali metal compound, an alkaline earth metal compound, a platinum group compound, etc. may be added or supported on these alone or in a mixture.

Note that this gas contact treatment with the inorganic catalyst may be applied to a packed bed of the inorganic catalyst in the form of granules, or to objects in the shape of filters such as fibrous, nicum-like, perforated plate-like, plate-like, etc. This can be done by passing a gas through it. At this time, only one type of packed bed or filter may be used, but in some cases, two or more types may be appropriately combined to improve the deodorizing effect, sterilizing effect, freshness keeping effect, and ozone decomposition effect.

The temperature at which the gas to be treated is brought into contact with the catalyst is 0-1.
It is suitable to select in the range of 50°C, 2-100°C.
℃ is preferred, and 5 to 80℃ is most preferred. However, the space velocity of the gas to be treated relative to the catalyst is l0cI-1,000
,000h r-', preferably 50 (1-500,000h r-', 1
,00 (1-250,000br r-' is most preferred).

According to the ozone treatment method of the present invention, various components and airborne bacteria in the gas to be treated are efficiently (ozonated). More preferably, hydrogen sulfide, mercaptans, sulfides, and disulfides in the gas to be treated are sulfur compounds such as
Odor components such as nitrogen compounds such as ammonia and amines, organic compounds such as hydrocarbons, aldehydes, ketones, and carboxylic acids can be efficiently removed, and deodorization treatment is possible.

Further, according to the ozone treatment method of the present invention, ethylene, esters, etc. in the gas to be treated can also be removed, making it possible to maintain the freshness of fruits and vegetables.

Furthermore, according to the ozone treatment method of the present invention, airborne bacteria in the gas to be treated can be sterilized.

(e) Function Ozone generally has strong oxidizing power and exhibits a wide range of functions such as deodorization, sterilization, and freshness preservation. In this invention, ozone is efficiently generated for a long period of time, and the generated ozone acts efficiently under the gas phase, under the liquid phase, or on the surface of the inorganic catalyst.

As a result, efficient deodorization, sterilization, and freshness preservation are possible for a long period of time, and unreacted ozone is also decomposed into oxygen on the catalyst surface.

(F) Embodiment FIG. 1 is an explanatory diagram showing an embodiment of an apparatus for carrying out the ozone treatment method of the present invention. As shown in the figure, the gas to be treated 1 is divided into two parts, a part of which is sucked by an air pump 2, brought into contact with an acid-carrying adsorbent 3, and then introduced into an ozone generator 4, where it is ozonated. Gas 5 is obtained. This ozonized gas 5 is added to the remaining gas to be treated, sucked by a fan 7 and mixed at high speed in an impeller section, and then brought into contact with an inorganic catalyst 8 and subjected to ozone treatment.

Furthermore, the gas sucked into the air pump 2 may be atmospheric air. In general, the atmosphere contains fewer impurities (especially ammonia and amines) than the gas to be treated.
Often suitable for ozone generation.

Example 1 Using the ozone treatment apparatus shown in FIG. 1, H2S 0, 15
ppm, CH3SH0, 10ppm, NHs 2.
A part of the atmosphere (gas to be treated) containing lppm (CH3)5N O, 05ppm is
The gas is separated at a rate of Ozonized gas 5 was obtained by passing the gas through a 25xxφ tube in which a silent discharge type plate-shaped ozone generating electrode 4 was housed.

This ozonized gas 5 is added to the above-mentioned gas to be treated, and the total amount of this mixed gas 6 (ozone concentration 4 ppm) is 125 Q/
1 trin is suctioned by the trickle fan 7, and mixed at high speed by the impeller (rotation speed 3100 times/+in, space velocity 190
,0OOhr"), then activated carbon honeycomb 8 (specific surface area 800 m'/IF, number of cells 300 cells/in' thickness 40
(2) at a linear flow rate of 20 cm/sec.

As a result of continuing this test for 20 days, the treated gas 9 discharged from the activated carbon honeycomb layer had no odor at all.

Comparative example! In Example 1, a test was conducted in the same manner as in Example 1 without using the activated carbon honeycomb supporting 10 wt% phosphoric acid.
After 15 hours, a strong odor became noticeable. When the test was stopped and the ozone generation plate was observed, white crystals were observed, and the amount of ozone generated had decreased significantly.

Example 2 Ht S-0,15p using the ozone treatment apparatus shown in FIG.
pm, CH3SH-0.05ppm, (CHt)>
S-0.03ppm, (CH3)! 52-0.0
1ppmNHZI, 3ppm, CH3CHOO
,03ppm.

CH3CHO-0.23ppm, 1so-C4HeC○
Atmosphere containing 0H-0,004ppm (gas to be treated)
3.5~1612/w with air pump 12 for a part of 11
This gas was added to 15 tvt% of citric acid.
Supported activated carbon (particle size 16-24 mesh, specific surface area 100
0 m'/9) filled layer 13 (diameter 100zzφ thickness 1
50xx), and this gas is passed through a silent discharge type air-cooled finned tubular ozone generating electrode tube 14 (inner diameter 8mm,
6 xxφ, length + 60Rx), ozone gas 1
Got 5. This ozonized gas 15 is added to the above-mentioned gas to be treated, and the entire amount of this gas 16 is sucked by a 710mm fan 17 at 710mm (1/min), and mixed at high speed in the impeller section (
Number of rotations 1800/win space velocity 2g, 000hr”
) After that, 5vt%Mn0t-supported cordierite honeycomb (300 cells/in', thickness 10+x) 19 and 5vt%, Kffi CO3-supported activated carbon honeycomb 20 (BET specific surface area 800m''/9.cells 300/ In'', thickness 30zx) at a linear flow rate of 40cm/sea.

Note that the linear flow velocity of the gas flowing to the ozone generating electrode etc. 14,
Ozone concentration and K v at sirocco fan outlet 18
Table 1 shows the results of investigating the deodorizing situation at the COs-supported activated carbon honeycomb outlet 21.

Comparative Example 2 Table 1 summarizes the results of testing in the same manner as in Example 2, without using the activated carbon honeycomb carrying 15 wt% citric acid.

From the results of Example 2 and Comparative Example 2 (Table 1), it is clear that when an acid-supported adsorbent is used as a pretreatment for the gas used to obtain ozonated gas, the ozone generation efficiency is stably high and deodorization ( However, if an acid-supported adsorbent is not used, the amount of ozone generated decreases rapidly and a good ozone treatment effect cannot be obtained.

(Margins below) Table 1 Example 3 In Example 1, an atmosphere containing tH- 2 ppm, (CH+)zN-0, O 5 ppm was used as the gas to be treated, and a test was conducted for 20 days in the same manner as in Example 1. To.

The average removal rates of CtH and (CH3)3N were both 99.95%.

Comparative Example 3 In Comparative Example 1, C, H, -2pp
m, (CH3) sN - When tested in the same manner as in Comparative Example 1 using an atmosphere containing 0.05 ppm, 15
The removal rate of C, H, after hours is 1083% (CH3)3N
The removal rate was 6.8%.

(G) Effects of the Invention According to the ozone treatment method of the present invention, it is possible to efficiently process the gas to be treated using ozonized gas, especially deodorization, sterilization, freshness preservation, etc. over a long period of time. This will solve the problem of residual ozone.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are configuration explanatory diagrams each illustrating an apparatus for carrying out the ozone treatment method of the present invention. ll... Gas to be treated, 12... Air pump, 13... Acid-carrying adsorbent, 14... Ozone generating electrode, 15... Ozone 16...Mixed gas, 17...Fan, 19.20...Inorganic catalyst, 21...Processing gas.

Claims (5)

[Claims] 1. After a part of the gas to be treated and/or the atmosphere is brought into contact with the acid-supported adsorbent, it is passed through a silent discharge type ozone generating electrode to generate ozone, and this ozonized gas and the remaining gas to be treated are combined. An ozone treatment method characterized in that the gas to be treated is treated by mixing and subsequently contacting with an inorganic catalyst capable of promoting ozone treatment. 2. Claim 1: Part of the gas to be treated and/or the atmosphere is first brought into contact with activated carbon and then brought into contact with an acid-supported adsorbent.
Ozonation method described. 3. 2. The ozone treatment method according to claim 1, wherein the ozonized gas and the gas to be treated are mixed by high-speed rotation means. 4. 2. The ozone treatment method according to claim 1, wherein the ozonized gas and the gas to be treated are mixed in water or hydrogen peroxide. 5. The ozone treatment method according to claim 1, wherein the flow rate of a portion of the gas to be treated and/or the air to the ozone generating electrode is about 250 cm/sec.