JPH0530959A - Porous carbon hollow body and its production - Google Patents

Abstract

PURPOSE:To obtain the subject product, having plural holes formed in an outer shell constructing a hollow part by a specific method, in which microorganisms can readily penetrate from the aforementioned holes and proliferate in the hollow part and suitable as a substrate for culturing the microorganisms without any difference in concentration of culture solutions in the hollow part. CONSTITUTION:Pitch is initially mixed with a low-boiling organic solvent (preferably benzene, etc.) as a foaming agent and a substance (e.g. polypropylene or charcoal), capable of gasifying in carbonizing and burning the pitch and having 5-50mum grain size is simultaneously added. The resultant pitch is subsequently pulverized to 32-3360mum (425-6 mesh) particle size. The pulverized pitch is then instantaneously heated at a higher temperature than the boiling point of the above-mentioned solvent and a lower temperature than the softening temperature of the aforementioned pitch to provide pitch fine hollow bodies. The resultant hollow bodies, as necessary, are subsequently classified, then treated with an oxidizing gas or liquid and infusibilized. The infusibilized fine hollow bodies are finally carbonized and burned in an inert gas atmosphere to afford the objective hollow bodies having plural holes 5 obtained by disappearance of particles by infusibilization and carbonization in the outer shell 4 constructing a hollow part 6.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a microbial culture substrate, an enzyme reaction reactor, a substance production carrier, etc., porous, hollow,
TECHNICAL FIELD The present invention relates to a porous carbon hollow body used for applications that make use of its light weight and a method for producing the same.

[0002]

2. Description of the Related Art Regarding the method for producing a carbon micro hollow body,
For example, as described in Japanese Examined Patent Publication No. 31447/1989, although the hollow body obtained here has minute pores communicating with the hollow portion, the number thereof is very small and not controlled, and the pores It is not intended to form.

Although spheres having a high porosity made of a cellulosic material are commercially available and used as a substrate for culturing microorganisms, these are not hollow bodies.

[0004]

Among the micro hollow bodies disclosed so far, in the case of a hollow body having a hollow interior, there is no internal or external communicating hole (usually 1 μm or more), or even if there are any. Was small, at one to several, and was not intended to create a hole. In addition, even if there are a large number of voids inside, those having a large number of walls at the same time are not necessarily preferable for the growth of microorganisms and the flow of liquid inside the hollow body.

According to the present invention, the inside of the hollow body is substantially hollow, and only the outer shell has pores through which a large number of microorganisms can pass, and the inside of the hollow body can be 100% utilized as a growth space for the microorganisms.
Moreover, it is an object of the present invention to provide a porous carbon hollow body capable of smoothly holding a liquid and flowing through a hole and hardly causing a concentration difference in a cavity, and a method for producing the same.

[0006]

According to a first aspect of the present invention for achieving the above object, there is provided a carbon micro hollow body having a plurality of holes in an outer shell constituting a hollow portion, wherein Provides a porous carbon hollow body obtained by extinguishing particles by infusibilization and carbonization.

Here, it is preferable that the diameter of the hole is 1 μm or more.

According to the second aspect of the present invention, the pitch in which a low boiling point organic solvent is mixed as a foaming agent is 32 to
Crushed to a particle size of 3360 μm (425-6 mesh),
This is higher than the boiling point of the low boiling point organic solvent, and is instantaneously heated at a temperature lower than the softening point of the pitch to be foamed into a pitch micro hollow body, which is, as it is, or after classification, an oxidizing gas or When producing a hollow carbon body by treating with an oxidizing liquid to make it infusible and then carbonizing and firing in an inert gas atmosphere, in the pitch, 5 to 5
Provided is a method for producing a porous carbon hollow body, which has a particle size of 50 μm and is characterized by adding a substance which is substantially gasified during the carbonization and firing.

The present invention will be described in more detail below.

First, the first aspect of the present invention will be described. The porous carbon hollow body of the present invention has a plurality of holes in the outer shell forming the hollow portion, and the hollow portion is formed by a cavity having no wall.

FIG. 1 is a sectional view schematically showing an example of the porous carbon hollow body. Reference numeral 4 denotes an outer shell forming a hollow portion of the hollow carbon body, 5 denotes a plurality of holes provided in the outer shell, and 6 denotes a hollow portion.

The shell thickness 4a of the outer shell 4 is usually 3 to 5 μm, though it depends on the size and the number of the holes 5.

The holes 5 are obtained by eliminating particles by infusibilization and carbonization.

The diameter 5a of the hole 5 differs depending on the intended use of the hollow body, for example, when the microorganism is used as a substrate for culturing microorganisms.

That is, among the microorganisms, rod-shaped bacteria (Escherichia coli etc.) are rod-shaped with a diameter of 0.2 μm and length of several μm, and yeasts and molds are around 10 μm or larger. Therefore, it is necessary to design the size of the pore diameter 5a so that the microorganisms having a size larger than that of the bacillus can pass through the pores 5 of the hollow body, but it is preferable that the size is 1 μm or more.

When the carbon hollow body designed as described above is used, microorganisms can easily enter the hollow body and grow in the hollow portion (cavity portion) 6 in the hollow body. In this case, the hollow portion 6 is filled with a culture solution or the like and serves as a place for proliferation and a reaction for producing a target substance. Easily done through.

The size of the hollow carbon body is not particularly limited.

Next, the second aspect of the present invention will be described. The present invention is directed to solving the problems described above
In the method for producing a carbon micro-hollow body described in No. 31447, a pitch before heating and foaming is mixed by mixing a predetermined amount of particles of an organic compound that is mostly gasified in a carbonization and firing step, and then heat-foaming to obtain a pitch. A pitch foam body (hollow body) having a large number of the particles in the outer shell is obtained, and thereafter,
By infusibilizing and carbonizing to eliminate the particles, a porous carbon hollow body is obtained.

The method of the present invention uses coal-based or petroleum-based pitch as a raw material. The softening point of the pitch used is 60 to 2
50 ° C is preferred. A pitch having a softening point of 60 ° C. or lower is not preferable because mutual fusion is likely to occur in the foaming process, and infusibilization and carbonization are difficult. Also has a softening point of 250 ° C.
The pitches described above are extremely special and expensive. A pitch satisfying such conditions can be obtained, for example, by subjecting coal tars to an appropriate heat treatment and then removing low-molecular weight components.

In the present invention, the organic compound to be mixed with the pitch may be any compound that is mostly gasified at the time of carbonization and firing described later, and examples thereof include synthetic resins such as polypropylene and wood flour. Regarding the particle size of the organic compound, organic compound particles having a particle size not less than the shell thickness of the pitch hollow body after foaming described later are preferable as an additive for forming pores in the porous carbon hollow body (see FIG. 2).

The shell thickness of the pitch hollow body is usually 3-5.
.mu.m, and it is desirable to add particles having a particle size of 5 .mu.m or more for forming the holes. Specifically, for example, the particle size is selected depending on the target microorganism, but is in the range of 5 to 50 μm. Even if the particle size exceeds 50 μm, it can be used for the purpose of the present invention, but the shell of the pitch hollow body or the carbon hollow body tends to be easily broken.

The amount of the organic compound particles added is selected according to the diameter and the number of holes formed in the hollow portion of the carbon hollow body to be obtained.

The foaming agent used in the present invention is a low boiling organic solvent compatible with pitch, has a boiling point at a temperature lower than the softening point of pitch used as a raw material, and has a molecular weight of pitch and that of the organic solvent. The larger the difference, the better. These are aromatic hydrocarbons such as benzene, toluene, xylene and naphthalene.

The content of the solvent used as the foaming agent varies depending on the type of pitch used as a raw material, the desired density of the porous carbon hollow body, etc., but the viscosity is such that it can be crushed in the crushing step. It is extremely important to add a blowing agent so that

Next, the process for producing the porous carbon hollow body of the present invention will be described in detail.

First, it is extremely important that the raw material pitch, the organic compound particles and the low boiling point organic solvent which is the foaming agent are mixed sufficiently uniformly. If the mixing is not sufficient, it causes nonuniform foaming in the foaming process, and the intended hollow body cannot be obtained. The content of the low boiling point organic solvent necessary for foaming may be 0.5 wt% or more, but if the amount of the foaming agent is too large, it becomes difficult to grind the mixture in the grinding step. It is desirable to set it to 20 wt% or less. Mixing is achieved by stirring at 100-250 ° C. under pressure in an inert gas atmosphere for 20-150 minutes.

In the crushing step, the crushing can be carried out by an ordinary atomizer, and the crushed particles do not need to be spheroidized beforehand. The particle size is 32 to 3360 μm (4
(25 to 6 mesh). 33
For particles larger than 60 μm, it is extremely difficult to find conditions for making the particles into hollow spheres in the foaming process,
If the particles are smaller than m, it is extremely difficult to obtain a single sphere because the particles tend to be fused due to electrostatic attraction or the like.

In the foaming step, the solvent-containing pitch particles are instantaneously heated at a temperature higher than the boiling point of the solvent used to obtain a pitch hollow body. In this case, you may perform according to a particle size as needed. The porosity can be adjusted by appropriately selecting the foaming temperature condition, and the bulk density of 0.05 to
It can be produced in the range of 0.7 g / cm ³ . However, if the foaming temperature is too high, the produced spheres will burst or the spheres will fuse to each other and the desired product cannot be obtained.

FIG. 2 is a sectional view schematically showing an example of a pitch hollow body before carbonization treatment. Since the particles of the hole-forming additive 2 are present at a plurality of locations in the pitch shell (outer shell) 1 forming the hollow portion 3, the particles 2 disappear and the desired holes 5 are obtained at the next infusibilization and carbonization. . 1a is the pitch shell 1
Is the shell thickness of.

In the infusibilization process step, the pits produced in the previous step are
The hollow body can be classified as it is or if necessary.
If the temperature is below the softening point of the pitch, an oxidizing gas
In other words, it oxidizes the pitch component with an oxidizing liquid. Oxidation
Air, NO ₂, SO₂Etc., oxidizing liquid
As the body, potassium permanganate, nitric acid, etc. are typical
Of these, air is considered economically.
Most preferred

In the carbonization process, the infusibilized pitch hollow body is subjected to 600 to 20 in a non-oxidizing atmosphere.
It is carried out by treating at a temperature of 00 ° C. for 20 to 300 minutes.

The hollow carbon body obtained as described above is
Particle size 30-4000 μm, bulk density 0.05-0.7 g /
It is mainly composed of a porous hollow body having an external spherical shape having a property of cm ³ . The carbon hollow body can be used for the purpose of the present invention even if the carbon hollow body is further subjected to a high temperature heat treatment depending on the purpose.

[0033]

EXAMPLES Next, the present invention will be specifically described with reference to examples.

(Example 1) A pitch having a softening point of 176 ° C. and a benzene-insoluble portion of 51% was used as a raw material, and the pitch was 500 g.
To 50 g of benzene, 10 g of polypropylene resin adjusted to a particle size of 5 μm was added, and the internal volume with a stirring blade was 1 l
The autoclave was charged into the autoclave, the inside was replaced with nitrogen gas, the temperature was raised to 150 ° C., and the mixture was stirred at 500 rpm for 2 hours. The solvent-containing pitch obtained was finely pulverized using an atomizer to obtain 325 to 8 mesh particles. The solvent-containing pitch particles are placed in a ventilation oven maintained at 130 ° C. to foam,
A hollow pitch body was obtained.

This pitch hollow body is heated in an air bath from room temperature to 3
The temperature was raised to 00 ° C over 4 hours to obtain an infusible material.
Further, the infusibilized pitch hollow body was heated in an electric furnace from 300 ° C. to 1000 ° C. for 4 hours in an argon atmosphere and held at 1000 ° C. for 1 hour. Thus, a porous carbon hollow body was obtained.

Example 2 Example 1 was repeated except that 5 g of wood powder having a particle diameter of 30 μm was added instead of the polypropylene resin.
A porous carbon hollow body was obtained by the same method as described above. Examples 1, 2
Each of the porous carbon hollow bodies obtained in 1. had a plurality of pores (diameter of 1 μm or more), and was sufficiently usable as a microorganism culture substrate.

[0037]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the hollow carbon body of the present invention has a large number of pores in its outer shell, and this hollow portion is a cavity without walls, and microorganisms Since it can easily enter the hollow body and grow in the inner cavity, the cavity in the hollow body can be used as a bioreactor and can provide a reaction site for exchanging an organic compound substrate (raw material) with a target product. .

By immobilizing the enzyme on the outer wall of the hollow body, it can be used as an immobilized bioreactor.

Industrial applications include fermentation industry, wastewater,
It can be used as a carrier for bioreactors, such as waste gas treatment and substance production by biotechnology.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an example of a porous carbon hollow body of the present invention.

FIG. 2 is a cross-sectional view schematically showing an example of a pitch hollow body before carbonization treatment.

[Explanation of symbols]

1 pitch shell (outer shell) 1a Pitch shell thickness 2 Pore forming additive (organic compound particles) Hollow part (hollow part) of 3 pitch hollow body 4 Carbon shell (outer shell) 4a Carbon shell thickness 5 Carbon shell holes 5a hole diameter 6 Hollow part (hollow part) of carbon hollow body

Claims (3)

[Claims] 1. A carbon microhollow body having a plurality of holes in an outer shell forming a hollow portion, wherein the holes are obtained by extinguishing particles by infusibilization and carbonization. . 2. The diameter of the hole is 1 μm or more.
The porous carbon hollow body according to 1. 3. A pitch in which a low boiling point organic solvent is mixed as a foaming agent is pulverized to a particle size of 32 to 3360 μm (425 to 6 mesh), and the pulverization is performed at a boiling point of the low boiling point organic solvent or more and It is heated instantaneously at a temperature lower than the softening point to foam it into a pitch micro hollow body, which can be treated as it is or after classification with an oxidizing gas or an oxidizing liquid to make it infusible, and then an inert gas atmosphere. Porous carbon characterized in that, when carbon hollowing is carried out in order to produce a hollow carbon body, a substance having a particle size of 5 to 50 μm and being substantially gasified at the time of carbonizing burning is added to the pitch in advance. Hollow body manufacturing method.