JPH0368418A - Treatment of waste ozone in corona discharger - Google Patents

Abstract

PURPOSE:To increase the efficiency of treatment of ozone generated from a corona discharger by decomposing the ozone with a specified catalyst before diffusion or dilution. CONSTITUTION:A layer 4 of an ozone decomposition catalyst consisting of a catalytic component selected among Ti, Si, Al, Mg and Zr and a catalytic component selected among Mn, Fe, Co, Ni, Ag, Au, Pt, Pd and Rh is formed so that the layer 4 confronts the ozone generating part of a corona discharger 2 and ozone generated from the discharger 2 is decomposed with the ozone decomposition catalyst. An electric conductor selected among metal powder, metal fibers, graphite and activated carbon may be added to the catalyst so that the catalyst can be directly heated by supplying electric current. By this structure, the efficiency of treatment of ozone is further increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for treating waste ozone from a corona discharger, and more particularly, it relates to a method for treating waste ozone from a corona discharger, and more particularly, it relates to a method for treating waste ozone from a corona discharger, and more particularly, it relates to a method for treating waste ozone from a corona discharger. This invention relates to a method for catalytically decomposing ozone generated near a corona discharger using a catalyst.

[Prior Art] In recent years, various electrical products with built-in corona dischargers, such as copying machines, laser printers, facsimile machines, etc. that use electrophotographic processes, have become widespread, and their use tends to become more frequent. ing. However, in the vicinity of the corona discharger, oxygen in the air is converted to ozone by corona discharge, and it has been pointed out that this ozone cannot be ignored from the standpoint of environmental hygiene. In other words, ozone itself is a disinfectant.
Although it can be used for various purposes such as bleaching and oxidizing, ozone emitted from copying machines etc. not only has an unpleasant odor but also has a strong poisonous effect on the human body, and if it exceeds a certain concentration it can cause respiratory problems. It has been found that inhalation of even small amounts can be extremely harmful.

As a method to treat ozone generated from copying machines, etc.,
Until now, methods such as (1) a treatment method using activated carbon and (2) a treatment method using an ozone decomposition catalyst have been implemented. However, in the case of treatment with activated carbon, due to the reaction mechanism between the activated carbon and ozone, the activated carbon is quickly consumed by oxidation, resulting in a short life and the trouble of having to frequently replenish activated carbon. Furthermore, when using an ozone decomposition catalyst, there is a limit to the amount of catalyst that can be installed in the exhaust gas path due to cost and pressure drop considerations, and the reality is that waste ozone cannot be completely treated.

[Problem to be solved by the invention] The present invention was made under these circumstances, and
The purpose is to provide a waste ozone treatment method that can efficiently decompose and remove waste ozone generated from copying machines and the like over a long period of time.

[Means for Solving the Problems] The present invention, which has achieved the above objects, includes the following (a) and (
A corona discharger characterized in that an ozone decomposition catalyst layer comprising the component b) is provided facing an ozone generation part of the corona discharger, and the ozone generated in the corona discharger is decomposed by the ozone decomposition catalyst. This is a waste ozone treatment method.

(a) A catalyst component consisting of one or more elements selected from the group consisting of Ti, Si, AI, Mg, and Zr; (b) Mn, Fe, Co, Ni, Ag, and Au.

A catalyst component comprising one or more elements selected from the group consisting of Pt, Pd, and Rh.

Further, the ozone decomposition catalyst layer used in the present invention may be configured so that it can be directly heated with electricity by further adding the following component (c) to the components (a) and (b). The effect of the invention is further enhanced.

(c) 1 fffi or two or more types of conductors selected from the group consisting of metal powder, metal fiber, graphite, and activated carbon.

[Function] The present inventors conducted studies from various angles from the viewpoint of increasing the efficiency of waste ozone treatment, and first of all, the following findings were obtained.

Conventional waste ozone treatment generally decomposes ozone near the exhaust port of the copying machine, and in this configuration, the ozone generated from the corona discharger is diffused and diluted. It will be processed. However, when ozone is diluted and the amount of air to be treated increases, it is difficult to completely treat ozone even if an ozone decomposition catalyst is used.

In other words, in order to decompose diluted ozone, it is necessary to increase the decomposition ability of the catalyst, but it is necessary to increase the decomposition ability of the catalyst, but it is necessary to increase the decomposition ability of the catalyst, but it is necessary to increase the catalyst layer pressure drop (the larger the pressure drop, the lower the air volume and the worse the heat removal effect), the catalyst installation space, and the catalyst Due to cost issues, etc., there is a limit to increasing the amount of catalyst used, and therefore there is a limit to the ozone treatment ability. It was thought that these factors determined the limits of the ozone treatment ability of the prior art.

Therefore, the inventors of the present invention conducted further research based on the idea that ozone should be decomposed in an undiluted state, and as a result, the inventors discovered that the ozone-containing air was transferred to the catalyst layer before the ozone was diffused and diluted. We thought that it would be a good idea to lead to this, and we found a configuration in which the ozone decomposition catalyst was installed facing the ozone generation part of the corona discharger.

On the other hand, the present inventors are also conducting research from the viewpoint of improving the ozone decomposition ability of the catalyst itself. This is despite the currently proposed catalysts having excellent ozone decomposition ability.
This is because it is considered difficult to completely fill ozone over a long period of time.

However, according to research by the present inventors, if a catalyst consisting of the following components (a) and (b) is used, corona discharge J!
The present invention has been completed based on the discovery that a stable ozone treatment effect can be exhibited over a long period of time under the ambient conditions.

(a) 1 fffi or 2. selected from the group consisting of Ti, Si, Al, Mg and Zr; f! ! Catalyst component consisting of the above elements (b) Mn, Fe, Co, Ni, Ag, Au.

A catalyst component consisting of one or more elements selected from the group consisting of Pt, Pd, and Rh; and in addition to the components (a) and (b), the following (c)
By adding the components, the catalyst can be directly heated by electrical heating, and when corona discharge is not being performed (for example, when preheating a copying machine), the catalyst itself can be preheated by being heated with electricity, or the It has also been found that it is even more effective to regenerate the catalyst by heating it with electricity after discharge.

, (c) 1 fffi or two or more types of conductors selected from the group consisting of metal powder, metal fiber, graphite, and activated carbon.

A specific configuration in which the ozone decomposition layer is provided facing the ozone generation part of the corona discharger includes, for example, a configuration in which the ozone decomposition layer is formed on the inner surface side (on the ozone generation part side) of the metal shield of the corona discharger. There are no particular limitations on the method of forming the catalyst in such cases, but representative methods include: ■ Making an ozone decomposition catalyst material into a paste form and applying it to the inner surface of the metal shield; Examples include a method of attaching a ceramic sheet carrying a catalyst substance to the inner surface of a metal shield.

Hereinafter, the present invention will be explained in more detail with reference to examples, but the following examples are not intended to limit the present invention.
Any design changes for the purposes described below are included within the technical scope of the present invention.

[Example] Figure 1 is a schematic explanatory diagram showing an example of an apparatus for carrying out the method of the present invention, and Figure 2 is a diagram showing the main parts thereof, where 1 is a photoreceptor drum, 2 is a corona. Discharge device, 2a is corona discharge wire,
4 is an ozone decomposition catalyst layer.

6 is a metal shield.

In the above configuration, ozone generated in the corona discharger 2 is decomposed by the ozone decomposition catalyst layer 4 formed on the inner surface of the metal shield 6, and air not containing ozone is discharged to the outside of the system.

According to experiments conducted by the present inventors, when ozone decomposition was performed using an ozone decomposition catalyst described below, a stable ozone decomposition ability was maintained over a long period of time.

The catalyst used at this time was prepared as follows.

First, a composite oxide consisting of Ti and St was prepared according to the following procedure.

As a Ti source, a sulfuric acid aqueous solution of titanyl sulfate having the following composition was used.

Ti0Si4250g/J! (TiOz conversion) Total 82
S04 1100 g/fl 400 square meters of water and ammonia water (NH, 25%) 280℃
and Snowtex-NCS-30 (silica gel manufactured by Nissan Chemical, containing approximately 30% melon as 5in2)
A solution containing 24 kg of sulfuric acid was prepared separately, and a titanium-containing sulfuric acid aqueous solution diluted by adding 153 parts of the above sulfuric acid solution to 300 parts of water was gradually added dropwise under stirring to produce a coprecipitated gel. TiO2-5iO2 obtained in this way
The gel was filtered, washed with water, and then dried at 200°C for 10 hours. Then, it was fired at 550° C. in an air atmosphere for 6 hours. The composition of the obtained powder was TiO,:5iO2=4+1 (molar ratio), and the BET surface area was ts5m''/g.

Using the obtained powder (hereinafter referred to as TS-1), an ozone decomposition catalyst was prepared according to the procedure described below.

Add an appropriate amount of water to 9 kg of the above TS-1 powder, mix well with a kneader, thoroughly knead with a kneader, and use an extruder to form a uniform kneaded product into a flat plate (thickness 111101 mm).
and dried at 150°C for 5 hours. Subsequently, it was impregnated with an aqueous solution of manganese nitrate, dried and calcined to obtain a catalyst having a weight ratio of TS-1:Mn0z=90:10 as oxides.

The obtained catalyst was attached to the inner surface of the metal shield 6 to form a structure as shown in FIG. 2.

An appropriate amount of water was added to a mixed powder of 8 kg of TS-1 powder obtained in the Higashi Δriyu Example and 1 kg of graphite powder, and the mixture was thoroughly mixed in a kneader, and then sufficiently kneaded in a kneader to obtain a uniform mixture. The kneaded product was molded into a flat plate (thickness: 1 mm) using an extruder and dried at 150°C for 5 hours. Subsequently, it was impregnated with an aqueous solution of manganese nitrate, dried and fired, and the weight ratio as an oxide was TS-1:graphite:Mn02=80:10.
:10 catalyst was obtained.

The obtained catalyst was attached to the inner surface of the metal shield 6 to form a structure as shown in FIG. 2.

Using the above ozone decomposition catalyst, ozone decomposition was carried out by alternately performing corona discharge (continuous 30 minutes) and energization heating of the catalyst (continuous 30 minutes), maintaining the temperature during energization heating of the catalyst at about 60 ° C. However, stable ozone decomposition ability was maintained over a long period of time.

[Effects of the Invention] As described above, according to the present invention, since the ozone generated from the corona discharger is decomposed by a catalyst before being diffused and diluted, the ozone treatment efficiency can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing an example of a device configured to carry out the method of the present invention, and FIG. 2 is an enlarged view of the main parts near the metal shield 6. 1... Photoreceptor drum 2... Corona discharge section 2a.
... Corona discharge wire 4 ... Ozone decomposition catalyst layer 6 ... Metal shield Figure 1 Noah

Claims (2)

[Claims] (1) When treating ozone generated from a corona discharger, an ozone decomposition catalyst layer consisting of the following components (a) and (b) is provided facing the ozone generation part of the corona discharger, and A method for treating waste ozone from a corona discharger, characterized in that generated ozone is decomposed by the ozone decomposition catalyst. (a) A catalyst component consisting of one or more elements selected from the group consisting of Ti, Si, Al, Mg and Zr, (b) Mn, Fe, Co, Ni, Ag, Au, Pt, P
A catalyst component comprising one or more elements selected from the group consisting of d and Rh. (2) When treating ozone generated from a corona discharger, an ozone decomposition catalyst layer composed of the following components (a) to (c) so that it can be directly heated with electricity is used to treat ozone generated from the corona discharger. A method for treating waste ozone in a corona discharger, characterized in that the ozone generated in the corona discharger is decomposed by the ozone decomposition catalyst, the ozone being disposed facing the generation part. (a) A catalyst component consisting of one or more elements selected from the group consisting of Ti, Si, Al, Mg and Zr, (b) Mn, Fe, Co, Ni, Ag, Au, Pt, P
(c) a catalyst component consisting of one or more elements selected from the group consisting of d and Rh; (c) one or more conductive elements selected from the group consisting of metal powder, metal fiber, graphite, and activated carbon; body.