JPH0259018A - Air cleaner - Google Patents

Abstract

PURPOSE:To obtain a compact air cleaner able to remove any kinds of harmful gases and fine particles perfectly by composing an adsorption part of the cleaner of an active carbon fiber and an ion-exchange fiber. CONSTITUTION:An adsorption part of an air cleaner is composed of an active carbon fiber and an ion-exchange fiber. By this composition, low adsorption function of the active carbon fiber against a basic gas and an acidic gas is compensated by the ion-exchange fiber. Further, in the case of a cationic ion exchange fiber or an anionic ion exchange fiber, the surface of the ion-exchange fiber is changed in (-) and (+), respectively therefore fine particles bearing the opposite electric charge can be removed by electrostatic adsorption and the ion-exchange fiber lowers the work load of a fine particle removing filter or takes over the function of the filter. Or, when an ion-exchange group is introduced into a fine particle removing filter itself by application of radiation graft polymerization, the efficiency of fine particle removal is remarkably increased without enlarging the pressure difference.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention provides clean air, which is the most important requirement in maintaining a comfortable living environment in relatively small living spaces such as small businesses and general households. That is, it relates to an air purifier that produces air that is odor-free and free of suspended particles.

(Prior Art) Types of air pollution are broadly classified into odors originating from gas components and those due to suspended particles, and the methods for removing them are completely different.

Traditional methods of deodorization include neutralization,
These include chemical deodorization using oxidation, reduction, etc., physical deodorization using activated carbon or zeolite as an adsorbent, and biological deodorization using bacteria or enzymes.

For chemical deodorization, chemical cleaning methods are known that use acidic or alkaline aqueous solutions such as hydrochloric acid, sulfuric acid, or sodium hydroxide aqueous solutions, or chemical cleaning methods that use sodium hypochlorite aqueous solutions as oxidizing agents. The same can be said of biological deodorization, which not only requires large equipment but also uses dangerous chemicals, making it unsuitable for small businesses or households.

The most common method for physical deodorization is to use activated carbon as an adsorbent, but since the adsorption rate and utilization rate of granular activated carbon are not very high, it is difficult to use it in its original form. Rather, it is suitable for large-scale processing using a packed column method. In order to increase the adsorption rate, there is an idea to crush granular activated carbon into fine particles, but this makes handling more inconvenient. Activated carbon fibers, which have a surface area comparable to that of powdered activated carbon, have recently been commercially available in molded forms such as mats and non-woven fabrics, and are easy to process into pleated shapes, etc., making them suitable for small businesses and general households. In places where a compact device is required, such as in the United States, it has received a certain amount of praise because it has both the functions of filtering particles and adsorbing gas components. However, although activated carbon has excellent adsorption performance for neutral gases, it has poor adsorption ability for acidic gases and basic gases, and no matter which form of activated carbon is used, this limitation cannot be overcome. Ammonia and trimethylamine, which are the main causes of toilet odor and rotten fish odor, belong to basic gases, and the adsorption ability for them is extremely poor.

On the other hand, known methods for removing particulates include filtration using a fibrous or porous material as a filter, electrical adsorption using electrification of the particulates, or a combination of these methods. However, filtering is suitable for small volume processing.

When removing particulates by filtration, in order to increase the removal rate, it is necessary to increase the opening and filling rate, which increases the differential pressure at the filter section, resulting in insufficient air volume.

As described above, an air purifier that can efficiently remove all kinds of harmful gas components and particulates has not yet been found.

The object of the present invention is to provide a compact air purifier that can completely remove all kinds of harmful gas components and particulates.

(Means for Solving the Problems) The air cleaner according to the present invention has activated carbon fibers and ion exchange fibers as adsorption parts, and is characterized by the combined effects of both.

Any type of activated carbon fiber can be used here, but
Short fibers are difficult to handle and are preferably in the form of woven fabrics, non-woven fabrics, or molded products such as cloak-like shapes.

The shape of the ion-exchange fibers is preferably woven fabric, non-woven fabric, or matte, but only short fibers are commercially available, and it is impossible to obtain them in such shapes. Point ray graft polymerization can introduce functional groups while taking advantage of the characteristics of the base material, so it can be used not only for short fibers and long fibers, but also for their molded products such as woven fabrics, non-woven fabrics, and mat-like base materials. Then, the ion-exchange fiber will be created in that shape.

Note that the radiation used here includes gamma rays, alpha rays, beta rays, electron beams, etc., and any of them can be used, but gamma rays and electron beams are particularly suitable for the present invention. There are various methods for radiation graft polymerization, such as simultaneous irradiation method and pre-irradiation method depending on the irradiation method, and liquid phase graft polymerization and gas phase graft polymerization depending on the method of contact between the base material and the monomer. Pre-irradiation gas phase graft polymerization is preferred due to its low cost and functional group distribution.

When the activated carbon fibers and ion exchange fibers in the adsorption part are both made of woven fabric, nonwoven fabric, etc., they can be used as they are by being attached to a frame or the like. Further, other polymeric fibers may be used in combination as a support agent, which is effective in the case of short fibers.

(Function) In this way, if you use an air purifier that has activated carbon fibers and ion exchange fibers as adsorption parts, you can solve the problem of activated carbon fiber's low adsorption ability for basic gases and acidic gases, which has been a problem in the past. can be supplemented by ion exchange fibers. Furthermore, since the surface of the ion-exchange fiber is charged to e in the case of cation-exchange fiber and e in the case of anion-exchange fiber, it is possible to remove particles of the opposite sign by electrostatic adsorption, and the particle removal filter The load can be reduced or shouldered. Alternatively, if an ion exchange group is introduced into the particulate removal filter itself using radiation graft polymerization, the particulate removal rate can be significantly increased without increasing the differential pressure.

(Example) Hereinafter, the present invention will be explained by examples.

Example 1 Polypropylene nonwoven fabric with a diameter of 30 am (fabric weight 100
g/m”) Accelerated electron beam is applied to two sheets at 20M in nitrogen atmosphere.
After rad irradiation, styrene was graft-polymerized on one sheet,
Next, sulfonation is performed to increase the ion exchange capacity to 3 meg/
A nonwoven fabric made of strongly acidic cation exchange fibers was obtained. The other one was graft-polymerized with chloromethylstyrene, and then converted into quaternary ammonium, resulting in an ion exchange capacity of 2.
A nonwoven fabric made of strongly basic anion exchange fibers having a strength of 5 meg/H was obtained.

The above two nonwoven fabrics and a nonwoven fabric (weighing 40g/m") made of activated carbon fibers with a diameter of about 25μm are 5C11 in diameter.
The fibers were cut into circular shapes and packed into a glass column with the same inner diameter in the order of cation exchange fiber, anion exchange fiber, and activated carbon fiber from above. Air containing incense smoke is introduced into this column at 21/
When flowed at a flow rate of 1 inch, the removal rate was 88% by weight.
No decrease in removal rate was observed even after 1 hour.

Comparative Example 1 Example 1 except that a nonwoven fabric made of polypropylene fiber as a base material was used instead of the strong acid and strong basic ion exchange fiber.
When incense stick smoke was removed under similar conditions, the removal rate was low at 45% from the beginning, and dropped to 18% after about 15 minutes.

Example 2 Using a column under the same conditions as Example 1, ammonia 1
When air containing 0 ppm was flowed at 2 f/win, the ammonia concentration at the outlet was not detected even after 1 hour.

Comparative Example 2 When the same ammonia-containing air as in Example 2 was passed through a column similar to that in Comparative Example 1, the ammonia concentration at the outlet was found to be approximately app-− from the beginning.

(Effect of the invention) Conventional air purifiers for small businesses and general households can simultaneously remove gas components and particulates without sacrificing the requirements necessary for small air purifiers, such as compactness, quietness, and safety. It was difficult to do so.

The present invention not only dramatically increases the range of gas components to be removed and becomes effective against almost all gas components, but also improves the removal efficiency of particulates, making it easier to create a comfortable living environment. Now you can.

Claims (1)

[Claims] 1. An air purifier having an adsorption section containing activated carbon fibers and ion exchange fibers. 2. The air purifier according to claim 1, wherein the ion exchange fiber is produced by radiation graft polymerization.