JPH0257976B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for treating waste ozone. [Prior Art] and [Problems to be Solved by the Invention] Ozone (O ₃ ) is used in a wide range of fields because of its strong sterilizing and oxidizing power. For example, it is used for water treatment such as high-level treatment of wastewater, for deodorization in residential areas and production processes, and for food storage and medical fields. Table 1 shows the uses and fields of use of O ₃ .

【table】

[Means for solving problems]

In order to solve the above problems, the present invention collects and removes ozone using a scavenger such as the ion exchange fiber, and irradiates the scavenger with ultraviolet rays to decompose the captured ozone and remove it. This is designed to maintain or restore the ozone capturing ability of the scavenger. That is, the present invention brings an ozone-containing gas into contact with an ozone-containing gas and an ozone-containing gas made of at least one of ion-exchange fibers and activated carbon in which an ion-exchanger is supported on natural fibers or artificial fibers, and also exposes the ozone-containing agent to ultraviolet rays. This is a waste ozone treatment method characterized by performing irradiation and decomposing the collected ozone. In addition, the present invention applies ozone-containing gas to at least one of the following treatments: catalytic decomposition treatment using an ozone decomposition catalyst, adsorption decomposition treatment using activated carbon, thermal decomposition treatment by heating, and absorption treatment using a chemical solution. An ozone-containing gas is brought into contact with an ozone-containing gas that is made of at least one of ion-exchange fibers and activated carbon in which an ion exchanger is supported by the fibers, and the ozone-containing agent is irradiated with ultraviolet rays to collect ozone. This is a waste ozone treatment method characterized by decomposing ozone. The present invention will be explained in detail below. First, to explain ion exchange fibers, they are natural fibers, man-made fibers (chemical fibers or synthetic fibers), or blended yarns or mixed yarns of these fibers that support cation exchangers and/or anion exchangers. This can be done by directly supporting it on a fibrous support.
After making it into a woven, knitted or flocked form,
This can also be supported. In any case, it is sufficient that the fiber ultimately supports an ion exchanger. The natural fibers include wool, silk, etc., the chemical fibers include rayon and acetate, and the synthetic fibers include those made from hydrocarbon polymers and fluorine-containing polymers. Alternatively, polyvinyl alcohol, polyamide, polyester, polyacrylonitrile, cellulose, cellulose acetate, etc. can be used. Examples of the hydrocarbon polymer include polyethylene, polypropylene, polybutylene, polybutene, polystyrene, polyα-methylstyrene, polyvinylcyclohexane, polyvinyl alcohol, polyamide, cellulose, cellulose acetate,
Aliphatic, aromatic, or alicyclic polymers such as polyester, acrylic, polyurethane, or copolymers thereof are used. In addition, examples of the fluorine-containing polymer include polytetrafluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and vinylidene-tetrafluoride-hexafluoride copolymer. A fluorinated propylene copolymer or the like is used. Furthermore, fibers made from natural materials such as wool, silk, cotton, and linen can also be used. A mixture of the above raw materials may also be used. These materials, that is, the support body is used as a porous material, and the support body can be easily grafted, has good O ₃ resistance,
A material with high mechanical strength and low cost is preferable, and can be appropriately selected in consideration of the shape of the device, economic efficiency, effectiveness, etc. When incorporating the ion exchange fiber into the O ₃ removal device, for example, a non-woven fabric, a woven fabric, a knitted fabric, a fibrous form, etc. are used as appropriate, and can be determined as appropriate in consideration of the O ₃ removal effect, economy, etc. . Note that the term "fibrous" refers to the state of ion-exchange fibers as they are, and can be applied in the form of filaments (long fibers) or fabrics. In addition, in the case of textiles, it can be constructed from multiple types of ion-exchanged fibers with different supports; for example, it can be constructed by using a blended yarn of multiple types of ion-exchanged fibers or by interweaving them. It is possible. Regarding ion exchange fibers, anion exchange fibers are more effective in O ₃ treatment than cation exchange fibers, but
In practice, since O ₃ is often accompanied by other odorous components and other pollutants, both anion exchange fibers and cation exchange fibers can be used for deodorizing purposes. For example, the former is an acidic gas (e.g.
H ₂ S, SO ₂ ), the latter being an alkaline gas (e.g.
Both are effective in collecting and removing NH ₂ ). Next, as the ion exchanger, various cation exchangers or anion exchangers can be used without particular limitation. For example, bodies containing cation exchange groups such as carboxyl groups, sulfonic acid groups, phosphoric acid groups, and phenolic hydroxyl groups, anion exchangers such as primary to tertiary amino groups, quaternary ammonium groups, sulfonium groups, and phosphonium groups. Examples include group-containing bodies, or polymerized or condensed type ion exchangers containing both the positive and negative ion exchange groups, and homogeneous or heterogeneous types. Typical examples of these include condensation polymers of sodium phenolsulfonate and aldehydes or ketones; condensation polymers of aromatic amines and aldehydes or ketones; acrylic acid, methacrylic acid, vinylbenzenesulfonic acid, styrene, and ar-halomethyl. Styrene, acyloxystyrene, hydroxystyrene, aminostyrene, vinylpyridine, 2
-Methyl-5-vinylpyridine, 2-methyl-5
- There are polymers of monomers having cationic or anionic exchange groups or groups convertible thereto, such as vinylimidazole, acrylonitrile, sulfuric acid, chlorosulfonic acid, and sulfonic acid. Copolymers of the above monomers with monomers having two or more double bonds such as divinylbenzene, trivinylbenzene, butadiene, ethylene glycol, divinyl ether, and ethylene glycol dimethacrylate, or polyethylene, polyvinyl fluorocarbon ether, and polytetra Ion exchangers include polymers obtained by graft polymerizing styrene onto fluoroethylene, into which cationic and/or anionic ion exchange groups are introduced or converted into ion exchange groups as required. Next, as a method for supporting the ion exchanger on the support, for example, the support may be exposed to ultraviolet rays or α rays, β rays, etc.
Irradiating with ionizing radiation such as beams, electron beams, and gamma rays,
Alternatively, there is a method of treating with an oxidizing agent such as oxygen, ozone, chlorosulfonic acid, hydrogen peroxide, benzoyl peroxide, peracetic acid, etc. to graft a monomer that forms an ion exchanger to support this. Specifically, for example, ion exchange fibers can be obtained by irradiating polyethylene with radiation, immersing it in a solution containing hydroxystyrene monomer and isoprene, performing graft polymerization, and after the reaction, performing quaternary amination. [Example] An example of the present invention will be described based on the drawings.
The drawing is a flow sheet when a primary treatment using a conventional ozone decomposition catalyst and a secondary treatment using a packing body filled with ion exchange fibers according to the present invention (hereinafter referred to as an ion exchange filter) are used together. . That is, 1 is waste O ₃ released from an O ₃ reactor (not shown) in sewage treatment, and relatively high concentration waste O ₃ 1 is a catalyst which is a reactor formed by filling an ozone decomposition catalyst. It is decomposed to a relatively low concentration in the filling section 2, and then processed in an ion exchange filter 3 to become a treated gas 4 with an extremely low concentration (0.1 ppm or less) and discharged. The decomposition catalyst is usually a metal oxide catalyst such as MnO ₂ , Co oxide-added MnO ₂ , FeO, NiO, etc.
Catalysts in which noble metals such as Ag, Pt, and Pd are supported on SiO ₂ or γ-alumina, or Ag, Pd, etc. in semiconductor materials, etc.
A photocatalyst is used that adds noble metals such as Pt and Pd and irradiates with light. The catalyst in this example was Co
It is _MnO2 with oxide addition. The catalyst filling section 2 is used so that the O ₃ decomposition rate here is usually about 90 to 99%. That is, in the catalyst filling part 2, the O ₃ concentration is several ppm to several thousand ppm, usually several tens of ppm to
Several hundred ppm of waste O ₃ is treated until the concentration is about 1 to several tens of ppm. Next, the waste O ₃ 1 is treated by an ion exchange filter 3 to a concentration of about 1 to several tens of ppm to 0.1 ppm or less, usually 0.05 ppm or less. The ion exchange filter 3 is exposed to ultraviolet light such as an ultraviolet lamp (not shown) at appropriate times, that is, continuously during the treatment of waste O ₃ or intermittently when the filter is almost saturated with O ₃ . Ultraviolet light is irradiated from the source, and the O ₃ captured by the ion exchange filter 3 is decomposed. Any source of ultraviolet light may be used as long as it emits ultraviolet light that can decompose O ₃ captured by the ion exchange filter 3. Further, as the normal ultraviolet rays, those having a wavelength of 150 nm to 300 nm, for example, ultraviolet rays around 254 nm are preferable. Note that among wavelengths shorter than 300 nm, it is preferable not to use ultraviolet light having a wavelength that produces O ₃ , for example, around 185 nm. _O3 to UV light
If a wavelength that generates is included, unnecessary wavelengths can be removed and used by a well-known method. For example, it may be removed by passing it through a filter for removing ultraviolet rays. Further, as the ultraviolet lamp, a low pressure mercury lamp, a medium to high pressure mercury lamp, or a deuterium lamp can be used. The filling amount and filling ratio of ion exchange fibers in the ion exchange filter 3, the form of ion exchange fibers, etc. are determined by the concentration and concentration ratio of the substance to be removed (O ₃ alone or O ₃ and odorous components), and the size of the filling container. It may be determined as appropriate by considering the shape, structure, use, effect, etc. In this embodiment, the ion exchange filter 3 is filled with anion exchange fibers and cation exchange fibers at a volume ratio of 4:1, since the filter also serves to remove malodorous substances at a sewage treatment plant. This example is a case where a catalyst method is used as the primary treatment method for waste O ₃ , and this primary treatment method is as follows:
Any method that can process a relatively high concentration of O ₃ to a relatively low concentration may be used, but a catalyst method or an activated carbon method is preferred from the viewpoint of treatment efficiency, cost, operability, equipment scale, etc. When the waste O ₃ has a relatively high to medium concentration, the preferred O ₃ treatment method is to perform a primary treatment using a conventional method, remove the waste O ₃ using ion exchange fibers and/or activated carbon, and remove this O ₃ by exposing it to ultraviolet rays. It is reasonable to use secondary treatment using a method of decomposition treatment by irradiation, and if the concentration is relatively low, to use the secondary treatment method alone, but depending on the type and scale of the source of waste O ₃ . , can be determined appropriately by considering coexisting components, economic efficiency, effects, etc. Note that the activated carbon for O ₃ collection may be of any type as long as it can capture O ₃ , and in addition to normal shapes such as granules, fibrous or band-like ones, and even those manufactured and processed using well-known methods can also be used. It is possible. Experimental example 1 (1) Experimental conditions Ozone-containing gas from an ozone generator (O ₃ concentration
10 ppm) was passed through the filter at a rate of 1/min, and the ozone concentration at the outlet was measured by long-term operation with and without irradiation of ultraviolet rays to the ion exchange filter or activated carbon. Ultraviolet source: Low pressure mercury lamp, 10W Ozone generator: Discharge method Type of ion exchange filter: Anion exchange filter Size of ion exchange filter: 100 mm x 100 mm
×30mm activated carbon; commercially available activated carbon for reagents, 100mm×100mm×
Filled to 30mm and used (2) Experimental results

[Table] Experimental Example 2 (1) Experimental Conditions As in Experimental Example 1, ozone-containing gas (O ₃ concentration 350 ppm) was generated from an ozone generator and passed through the waste ozone treatment equipment shown in the drawing at a rate of 2/min. The ion exchange filter was operated continuously for a long time with and without ultraviolet irradiation, and the outlet ozone concentration was measured. Ultraviolet source: Low pressure mercury lamp, 10W Ozone generator: Discharge method Type of ion exchange filter: Anion exchange filter Catalyst: Co oxide added MnO ₂ (150℃) Equipment size (mm): 200 length x 200 width x 250 High(2) Experimental results

〔Effect of the invention〕

1. When treating waste O ₃ , by using a specified O ₃ scavenger and irradiating it with ultraviolet rays, waste O ₃ can be treated with high efficiency and stably for a long period of time, and the concentration of discharged O ₃ can be effectively reduced. Contaminants other than O ₃ (such as odorous substances, e.g.
So ₂ , H ₂ S, NOx, HCl, NHO ₃ , NH ₃ , various solvents, solvents, malodorous substances (mercaptan,
It can simultaneously collect and remove sulfides, thiophenes), tar-like substances, or fine particles, and eliminates the need to replace the O ₃ collector. 2. Waste O ₃ from a wide variety of sources can be treated by combining a method of irradiating a specified O 3 scavenger with ultraviolet rays and a conventional O ₃ treatment method using _an ozone decomposition catalyst. In other words, this is a practically effective processing method that takes advantage of the strengths of each. Specifically, since the conventional O ₃ treatment method is based on a decomposition reaction, the higher the O ₃ concentration, the more
Effective. On the other hand, since the method using the O ₃ scavenger is thought to be mainly based on adsorption, the lower the concentration, the more effective it is. Not only continuous operation and intermittent operation but also highly practical treatment is possible even when the waste O ₃ concentration fluctuates considerably.

[Brief explanation of drawings]

The drawing is a flow sheet illustrating an embodiment of the invention. 1... Waste O ₃ , 2... Catalyst filling section, 3... Ion exchange filter, 4... Processing gas.

Claims (1)

[Claims] 1. Bringing an ozone-containing gas into contact with an ozone-containing gas comprising at least one of ion-exchange fibers and activated carbon in which an ion-exchanger is supported by natural fibers or artificial fibers, and the ozone-containing agent A method for treating waste ozone, which comprises irradiating the ozone with ultraviolet rays and decomposing the collected ozone. 2 The ultraviolet irradiation has a wavelength of 150 nm to 300 nm.
The treatment method according to claim 1, which is carried out using ultraviolet rays. 3. The treatment method according to claim 1 or 2, wherein ozone-containing gas is brought into contact with a fabric, knitted fabric, or nonwoven fabric made of the ion exchange fiber. 4. The treatment method according to claim 1 or 2, wherein the filling body formed by filling the filament or cloth of the ion exchange fiber is brought into contact with an ozone-containing gas. 5 Claim 1 in which the ion exchange fiber is one that supports an anion exchanger.
The processing method described in any one of Items 1 to 4. 6. The treatment method according to claim 5, wherein the ion exchange fiber is a natural fiber or an artificial fiber graft-polymerized with an ion exchanger. 7 After the ozone-containing gas is subjected to at least one of the following treatments: catalytic decomposition treatment using an ozone decomposition catalyst, adsorption decomposition treatment using activated carbon, thermal decomposition treatment by heating, and absorption treatment using a chemical solution, ions are added to natural or artificial fibers. Ozone-containing gas is brought into contact with an ozone scavenger made of at least one of ion exchange fibers and activated carbon supporting an exchanger, and the ozone scavenger is irradiated with ultraviolet rays to decompose the captured ozone. A method for treating waste ozone, characterized by: