JPH03234891A - Activated carbon fiber sheet and filter - Google Patents

Abstract

PURPOSE:To provide the subject sheet containing activated carbon fiber and mycelia produced by mold, exhibiting sufficiently high strength by the use of a small amount of binder, free from the trouble of clogging the fine pore of activated carbon fiber, exhibiting high adsorptivity and air transmissible property and usable without causing the falling off of activated carbon fiber. CONSTITUTION:The objective sheet contains activated carbon fiber and preferably 1-30wt.% of mycelia produced by mold. The sheet is suitable as a filter having a honeycomb structure.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an activated carbon fiber sheet with excellent strength and workability, which is obtained by mixing activated carbon fibers and mycelium produced by filamentous fungi, and is obtained by ordinary wet papermaking. .

[Prior art]

In recent years, foul odors and toxic gases such as organic solvents have been increasingly discussed as pollution problems. Adsorptive substances are used as a means to prevent these problems, and active carbon fibers are being rapidly developed because of their extremely high gas adsorption speed.

When activated carbon fibers are used in the form of a sheet, a binder is required to form the sheet because the activated carbon fibers themselves do not have self-adhesive properties. As the binder, various solution-type and emulsion-type liquid binders and fibrous binders are generally used.

The use of a liquid binder is not preferred because it blocks the pores of the activated carbon fibers and reduces the adsorption capacity.

The use of a fibrous binder requires a large amount of fibrous binder to prevent the activated carbon fibers from falling off and to obtain a sheet with sufficient strength, which reduces the content of activated carbon fibers in the sheet. Commonly used fibrous binders include cellulose fibers such as wood pulp, hemp pulp, and cotton pulp, but if the content of cellulose fibers in the sheet increases to increase sheet strength, the sheet becomes flammable. , its uses are limited.

Also, Special Publication No. 59-35341 and Special Publication No. 59-51
As shown in Publication No. 432, when processing into a honeycomb shape, corrugation workability is required, and the sheet needs to have a bulk density above a certain level, and in order to increase the density, more binder is required. In such a case, not only will the amount of activated carbon fibers decrease, but the air permeability of the sheet may also deteriorate.

As described above, it is difficult to achieve both improvement in sheet strength and workability and adsorption properties of the sheet.

JP-A-64-13789 exemplifies an activated carbon fiber sheet using bacterial cellulose produced by microorganisms. Bacterial cellulose can be used to form sheets, but the disadvantages of bacterial cellulose are that it has low freeness and has strong cohesiveness, resulting in poor formation.

Bacterial cellulose is produced by culturing bacterial cells and using substances produced outside the bacterial cells, whereas examples of using the bacterial cells themselves for paper production include Japanese Patent Publication No. 5710240 and British Publication Patent No. 2165865. is raised.

The former only describes mixing filamentous fungi with pulp and synthetic pulp and using the pulp as an extender, but does not mention anything about binders for functional sheets.

The latter method actively washes filamentous fungi with alkali to remove substances other than chitin that cover the surface of mycelia, exposing chitin and chitosan, and making use of the characteristics of chitin and chitosan themselves to create non-woven fabrics for injuries and illnesses, and ionized fabrics. It describes its use as an exchange body. This article describes how to take advantage of the characteristics of chitin and chitosan, but there is no mention of how a small amount of filamentous fungi can be used as a binder without being washed with alkaline to exert a binder effect.

As described above, there are limited examples of using filamentous fungi as a binder for other fibers, and there are no examples of using filamentous fungi as a binder for activated carbon fibers.

[Problem to be solved by the invention]

The present invention solves the above-mentioned conventional problems, and provides a sheet that has high strength and maintains the high adsorption capacity of activated carbon fibers by simply blending a small amount of a specific fibrous binder with activated carbon fibers. The object of the present invention is to provide a sheet with good processability and a filter manufactured using the sheet.

[Means to solve the problem]

The present inventors conducted extensive research to solve the above problems. As a result, by using mycelium produced by filamentous fungi as a binder for activated carbon fibers, a high-strength sheet can be obtained without impairing the adsorption ability of activated carbon fibers.
The present invention was completed by discovering that it is possible to impart workability to a honeycomb structure suitable for filters.

That is, the present invention is an activated carbon fiber sheet containing activated carbon fibers and mycelium.

The activated carbon fiber sheet described above can be used as a filter, and can be processed into a honeycomb structure and used as a filter.

The present invention will be explained in detail below.

The activated carbon fiber used in the present invention differs from ordinary carbon fiber in that it has micropores on the fiber surface, and has a specific surface area of
Adsorption capacity etc. can be selected depending on the purpose, but specific surface area 500
r+f/g or more and benzene adsorption capacity of 200 mg/g or more are preferable. The activated carbon fibers may be those that can be dispersed in water, and if they are difficult to disperse, a sticky agent or a dispersant may be appropriately added and stirred. Average fiber length is 0.05mm to 1.5I
l+m, preferably 0.5 mm to 10 mm.

If it is shorter than 0.05 mm, the breathability of the sheet will decrease, and 15
If the length is longer than mm, dispersion in water will be poor.

Bacterial cellulose uses cellulosic substances produced outside the bacterial cells by culturing bacteria, whereas the mycelium produced by the filamentous fungi used in the present invention is produced by the bacterial cells themselves growing into a fibrous form. It is different from bacterial cellulose because it uses what has become, that is, the bacterial cells themselves. This bacterial cellulose can also be used to form sheets of activated carbon fiber, but those using the mycelium of the present invention have a better texture than those using bacterial cellulose, and the sheets are flexible, so they can be rolled up. superior in that which is good in nature.

The mycelium produced by filamentous fungi used in the present invention refers to molds (Aspergillus sp., Rhizopus sp., Fusarium sp., Subrolegnia sp., Mucor sp., Diplobuia sp., Cercospora sp., Trichothecium sp., Penicillium sp., Trichoderma sp., Neurospora sp. (Botrytis sp., Trichutium sp., Chaetomium sp., Endosia sp., etc.)
, yeasts (genus Candida, etc.), actinobacteria (genus Streptomyces, etc.), bacteria (genus Mycobacterium, etc.).

Refers to all mycelial organisms such as Basidiomycetes (Heterobacision, Laetiporus, Tyromyces, etc.) and algae (Photolibuium, Sperulina).

A medium suitable for each mycelium containing organic and inorganic nutrients (for example, YM medium in the case of mold) is used. At this time, the concentration of organic nutrients in the medium should be 1/10 to 1/1 of the normal concentration.
/100 is also possible and is economically superior. The stirring is
The mycelium may harden into balls, so gentle agitation or standing conditions are preferable, but if there is no risk of the mycelium forming into balls, you can shake it to promote growth. good. Temperature: 5-95℃, period: 1 day ~
This will be done for a period of 90 days.

The mycelium obtained by culturing can be used as is, but mycelium contains various components such as proteins, nucleic acids, lipids, and inorganic salts in addition to polysaccharides such as cellulose and chitin. They can also be removed by appropriate treatment. For example, in the case of protein, an alkaline solution,
Lipids can be removed by immersion in an organic solvent, and inorganic salts can be removed by immersion in an acid solution. In addition, the mycelium may be colored, but this can be decolored by the above-mentioned treatment or bleaching, depending on the purpose. Normally, the mycelium of the present invention can be treated using ordinary pulp purification processes, such as alkaline treatment and bleaching treatment.

The mycelium obtained in this way is well entangled with activated carbon fibers, and the wet paper formed on the wire of the paper machine is strong, so it is easy to transfer to the next process, and it can be used in normal paper making. Can be manufactured efficiently using equipment. Another feature is that mixing mycelium improves the dispersion of the slurry, so a uniform sheet can be easily obtained.

The sheet can be obtained by uniformly dispersing and mixing the mycelium and activated carbon fibers in water, making an aqueous slurry using a conventional paper machine, and drying.

The amount of mycelium is 1% to 30% by weight based on the weight of the sheet.
The amount is preferably 5% to 20% by weight. If the mycelium is less than 1% by weight, the strength of the sheet will be weak;
If the amount is larger than this, the freeness of the slurry will deteriorate, which is not preferable in terms of the papermaking process.

In addition, the activated carbon fibers and mycelium can be mixed not only after the mycelium has been prepared, but also by adding activated carbon fibers to the medium and preparing a composite of activated carbon fibers and mycelia during cultivation, if necessary. It's okay.

If necessary, the activated carbon fiber sheet described above may be subjected to a submersion process by spraying, coating, impregnating with a submergence agent, and drying the sheet. Alternatively, paper may be made by mixing a sizing agent with the slurry.

Activated carbon fiber sheet can be made with other wood pulp, if necessary
Natural fibers such as hemp pulp and cotton pulp, recycled fibers such as rayon fibers and cupra fibers, synthetic fibers such as polyester fibers, polyamide fibers, polyvinyl alcohol fibers, polyolefin fibers, and polyacrylonitrile fibers, ceramic fibers, rock wool fibers, and sepiolite. It is also possible to mix inorganic fibers such as glass fibers and make paper. In addition, zeolite, activated alumina, acid clay, silica gel,
It is also possible to mix adsorbent substances such as diatomaceous earth and granular activated carbon to make paper. Furthermore, it is also possible to mix an inorganic filler and make paper. Furthermore, it is also possible to contain chemical deodorants and natural/synthetic fragrances. However, it goes without saying that these contents must not be within a range that impairs the performance of the sheet of the present invention.

0 The activated carbon fiber sheet can be easily cut with a cutter, slitter, etc., and can be incorporated into a unit and used as a filter. In addition, even if corrugated, it will not be damaged, and one-sided or double-sided corrugated cardboard can be made and laminated so that the ridge lines of the corrugations are parallel or perpendicular, or wrapped in a cylindrical shape to form a honeycomb structure. It is particularly effective to use it as a filter.

[For production]

The activated carbon fiber sheet of the present invention uses mycelium as a binder for activated carbon fibers, and is a high-strength sheet that does not block the pores of activated carbon fibers with an unprecedentedly small amount of binder. It acts effectively as a filter with a large amount of adsorption. Additionally, a honeycomb structure is created by applying corrugated processing, which effectively acts as a filter.

〔Example〕

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples.

In the examples, all parts and percentages are by weight.

For Examples 1-4, mycelium was prepared as follows.

The following two types of culture media were used.

(Medium ■) Yeast extract rough I-0.3 g.

Malt extract 0.3g, polypeptone 0.5g
, glucose 1-, Og, tap water 1.0g, pH 7.
Adjusted to 0.

(Medium 11) Yeast extract 3g 1 polypeptone 5g, glucose 1
0g, agar 20g, tap water 1. OB and pH were adjusted to 7.0.

A mold (Aspergillus oryzae ATCC 1 5240) was precultured on medium ■ at 30°C for 3 days.

The precultured mold was suspended in physiological saline. The absorbance is 2.
53 (600 nm), and this was inoculated into medium I at a rate of 2%. The cells were cultured at 30° C. for 2 days with gentle rotation at 30 rpm using a magnetic starter.

After culturing, the mycelium produced from the culture solution was washed with a sufficient amount of water while being suction-filtered. This mycelium was used in the following examples.

(Examples 1 to 3) Activated carbon fiber (manufactured by Nippon Kynol Co., Ltd., specific surface area: 15
00 m2/g, benzene adsorption capacity 530 mg/g) was added to water to adjust the concentration to 0.3%, and after dispersing with an SV type reciprocating stirrer (manufactured by Takasaki Seisakusho, Agitator), the previously prepared mycelium was added. were added and mixed while stirring in an agitator.

At this time, the ratio of activated carbon fiber to mycelium during drying was 9575.
, 90/10, and 80/20. Next, water was added to the slurry to dilute each to 0.1%, and a sheet with a dry weight of 70 g/rrr was made using a square hand paper machine (wire mesh 80 mesh, wire mesh size 2 5 cm x 2 5 cm).
After paper making in step m), it was pressed and dried to obtain an activated carbon fiber sheet.

(Example 4) The mycelia prepared above were collected in an amount equivalent to 10 g on an absolute dry basis, and steam sterilized with 2% NaOH at 120° C. for 20 minutes. After treatment, it was washed and the absolute dry weight was measured, which was 2.5g.
Met. Using mycelium subjected to the same treatment, Examples 1-
Using the same method as in 3, the blending ratio of activated carbon fiber and mycelium is 9.
An activated carbon fiber sheet with a ratio of 0/10 was obtained.

(Comparative Examples 1 to 4) Bleached softwood pulp (NBKP,
(freeness CSF 185ml), Seviolite (manufactured by Sangatsu Mining Co., Ltd.), polyester binder fiber (manufactured by Unitika Co., Ltd., core-sheath type Merchii #4080SD, fiber diameter 4 denier, fiber length 5mm), hot water soluble PVA fiber (manufactured by Kuraray Co., Ltd., Vinylon) VPB-105, fiber diameter 2 denier, fiber length 3
mm) were added and mixed. The mixing ratio is 90 for PVA fiber.
/10 and 70/30 for the rest, and a sheet was obtained by the above method.

Above, the measurement results of physical properties of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1. ]. Item 1] is basis weight, thickness, tensile strength, breaking length, benzene adsorption capacity (J I SK14 3 4 17), smooth star air permeability (manufactured by Toei Electronics Co., Ltd., smooth star, type 5M-6A). use).

In addition, the presence or absence of shedding of activated carbon fibers during cutting with scissors and corrugation processing, and the combustibility of the sheet were investigated.

The above results are shown in Table 1.

As is clear from Table 1, mycelium exhibits an excellent binder effect even in small amounts. Although PVAI fibers also exhibit the same strength as mycelium, there is a significant decrease in the amount of benzene adsorbed, which is thought to be due to clogging of the pores on the surface of the activated carbon fibers. Further, even during cutting and corrugation processing, the activated carbon fibers did not fall off as was the case with other binders. In addition, mycelium exerts a binder effect in small amounts, so NB
While the sheet using KP was flammable, the sheet I of the present invention exhibited self-extinguishing properties.

Furthermore, even when the mycelium was treated with NaOH, the effect as a binder did not change.

(Example 5) Mycelium was prepared as follows.

The following two types of culture media were used.

(Medium ■) Tap water was added to 39 g of potato dextrose agar medium (manufactured by Eiken Kagaku Co., Ltd.) and 5 g of agar, and the pH was adjusted to 5.6 (using hydrochloric acid and caustic soda).The total volume was filled up to 1 g. 150 mI each was dispensed into a roof flask and sterilized by autoclaving at 120°C for 20 minutes.

(Medium ■) Yeast extract 3g, malt extract 3g (manufactured by Difco), polypeptone 5g
(manufactured by Daigo Nutrition Co., Ltd.), add tap water to 20g of glucose,
(To adjust the pH to 7.0, hydrochloric acid and caustic soda were used) The entire solution was filled up to 19. 1.5 g of the culture medium was dispensed into a 3 g capacity Kolben, and sterilized by autoclaving at 120° C. for 20 minutes.

Mold (Fusarium socini) was cultured on medium ■ at 28°C for 3 days. After culturing, 30 ml of physiological saline was added to each roux to thoroughly suspend the grown mold cells. The suspension was permeated through sterile cotton, and the resulting spore suspension was 1. The solution was dispensed into ml portions, stored at -80°C, and melted and used as needed. The spore suspension was inoculated into medium ■ at a rate of 1 ml per 1 g, and incubated at 28°C for 2 days.
Culture was performed at 80 strokes/min. The culture solution was filtered using a 200-mesh sieve and washed repeatedly with pure water. This mycelium was treated in the same manner as in Example 3, and the ratio of activated carbon fiber to mycelium upon drying was adjusted to 80/20 to obtain an activated carbon fiber sheet.

(Example 6) Mycelium was prepared as follows.

Two types of media were used: medium (■) and medium (■).

A fungus (Deipropuia natalensis) was cultured on medium ■ at 28°C for 3 days. After culturing, physiological saline was added to thoroughly suspend the grown fungal hyphae, and the resulting suspension was inoculated into medium (2) and cultured at 28° C. for 2 days at 80 strokes/min. The inoculation rate is 1 slant per 1 g.
It was my duty.

The culture solution was filtered using a 200-mesh sieve and washed repeatedly with pure water. This mycelium was prepared in the same manner as in Example 3, and the ratio of activated carbon fiber to mycelium when dried was 80/
20 to obtain an activated carbon fiber sheet.

(Examples 7 to 16) In the same manner as in Example 6, mold (Cercospora:A-
+)-f! -'IC Example 7), mold (Trichothecium roserum) (Example 8), mold (Mucor leuxianus, IF05773) (, Example 9), mold (Penicillium fistulinum, ATCC9849) (Example 1)
0), mold (Trichoderma reesei, ATCC117
109) (Example 11), Mold (Neurospora φ Crassa, ATCC 36373) (Example 12), Mold (Botrytis Cinelli CB5241.62) (Example 1)
3), mold (Trichophyton mentagrophytes, IFO7522) (Example 14), mold (Chaetumium anahericinum NHL2390) (Example 15)
, Mold (Endosia Varasitya, CB5114.
13) (Example 16), mycelium was prepared according to Example 6, and an activated carbon fiber sheet was obtained. Table 2 shows the measurement results of the physical properties of the obtained sheet. The items are the same as in Examples 1-4.

one 0 (Example 17) Mycelium was prepared as follows.

As the culture medium, two types of compositions, medium H and the following medium V, were used.

(Medium V) Yeast extract 3g 1 malt extract 1-3g, polypeptone 5g 1 glucose 20
g1 activated carbon fiber (manufactured by Nippon Kynol Co., Ltd., specific surface area 15
00m2/g, benzene adsorption capacity 530mg/g)
12 g, tap water 1.04), and the pH was adjusted to 7.0. Dispense 1.5 g of the medium into a 3 g capacity container and heat at 120°C.
, sterilization was performed by autoclaving for 20 minutes.

Mold (Aspergillus spp.
oryzae, ATCC 15240) was precultured. The precultured mold was suspended in physiological saline.

The absorbance is 2. 53 (600 nm), and this was inoculated into medium V at a rate of 2%. The mixture was cultured at 30° C. for 2 days with gentle rotation at 30 rpm using a magnetic cooler to obtain an activated carbon fiber-mycelium composite in which mycelium was attached to the activated carbon fiber. Activated carbon fiber-mycelium was washed with water on a 200 mesh sieve.

Then, the composite was coated with 1000 times (weight M) of activated carbon fiber.
of water and the sheet with a dry weight of 70 g/rrF was made using a winter type hand paper machine (wire mesh 80 mesh, wire mesh size 25 x 25 cm).
) After paper making, press drying was performed to obtain an activated carbon fiber sheet.

Even if activated carbon fiber is added from the beginning, mold cultivation,
There was no hindrance to the treatment process, and the fungal mycelium showed the same excellent binder effect.

(Example 18) A 0.18% concentration of fluorine-based water repellent (
A water-repellent treatment was performed by impregnating Sumilettes FP-210 (manufactured by Sumitomo Chemical Industries, Ltd.), squeezing out water, and drying. The amount of water repellent applied was 0.46% based on the weight of the sheet. When I dropped water on it with a pipette, it repelled the water and showed a water-repellent effect.

Compared to the sheet of Example 2, almost no decrease in strength or adsorption capacity was observed.

2 3 [Effects of the Invention] The activated carbon fiber sheet of the present invention consists of activated carbon fibers and mycelium. Compared to activated carbon fiber sheets that use conventional binders, it has sufficient strength with a small amount of binder, does not block the pores of activated carbon fibers, has high adsorption properties, does not cause activated carbon fibers to fall off, and is breathable. I was able to get a good sheet.

This sheet can be used as a filter. It also has high strength and good workability, so it can be processed into a honeycomb structure and used as a filter. Furthermore, the genus of the mycelium used in making this sheet is not limited, and the present invention applies to all organisms that form a mycelium.

Claims (4)

[Claims] (1) An activated carbon fiber sheet containing activated carbon fibers and mycelium produced by filamentous fungi. (2) The activated carbon fiber sheet according to claim (1), which contains mycelium in a range of 1% to 30% by weight. (3) A filter comprising the activated carbon fiber sheet according to claim (1) or (2). (4) The filter according to claim (3), which is formed into a honeycomb-like structure.