JPH0265782A - Production of microorganism-immobilized granular gel - Google Patents

Abstract

PURPOSE:To obtain the subject gel useful for purification of waste water by dropping suspended aqueous solution comprising mixture of polymerizable compound, polymerization agent, gelling agent, colloidal silica and microorganism into specific mixed aqueous solution and polymerizing. CONSTITUTION:A water-soluble polymerizable compound is mixed with either one of polymerization accelerator such as calcium persulfate- dimethylaminopropionitrile or polymerization initiator, microorganism such as bacteria, gelling agent composed of salt of at least divalent metal such as calcium chloride and colloidal silica to form suspended aqueous solution. Next, said suspended aqueous solution is dropped into mixed aqueous solution containing sodium alginate and remained one of polymerization accelerator and polymerization initiator of said polymerizable compound to form strong liquid drop, then said polymerizable compound is polymerized within the liquid drop to afford the aimed spherical gel with simple process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a microorganism-immobilized granular gel useful for purifying wastewater.

[Conventional technology]

Entrapping methods are often used to immobilize microorganisms, and examples of entrapping immobilization materials include hydrophilic gels made from natural polymers and synthetic polymers. When looking at the durability of the carrier, synthetic polymers are considered to be advantageous because natural polymers are insufficient. Examples of past applications include many carriers such as polyacrylamide gel, polyvinyl alcohol gel, urethane prepolymer gel, photocrosslinked resin gel, and polyethylene glycol methacrylate gel.

When immobilizing microorganisms on these hydrophilic gels and using them as microorganism immobilization carriers, various shapes can be considered, such as spheres, etc.
There are particle shapes such as cylinders and prisms, and relatively large plate shapes such as films and sheets. When treating wastewater by filling a reactor with these carriers, considering the reaction efficiency, it is generally advantageous for the shape of the carrier to have a larger specific surface area (cmz/cI113/gel). Particulate carriers are preferred.

Molding a hydrophilic synthetic polymer gel into granules is quite elegant, but JP-A-59-11182 discloses a method for granulating a photocurable resin, and JP-A-63-2/1886 describes a method for granulating a photocurable resin. Method for granulating acrylamide gel, JP-A-60-
1537! ] - Publication No. 1 proposes a method for granulating a mixture of acrylamide and alginate.

The method described in JP-A No. 59-11182 is a method for gelling a suspended aqueous solution containing a photocurable resin prepolymer, a photosensitizer, a natural polysaccharide such as sodium alginate, and oxygen. Since resin prepolymers alone cannot gel into particles, they rely on natural polysaccharides that easily gel with metal salts.

That is, by utilizing the property that when sodium alginate is dropped into an aqueous calcium chloride solution from a nozzle, sodium and calcium ions are substituted and a spherical gel body is easily formed. Dropped into an aqueous solution, sodium alginate gels to form spherical primary particles, and the spherical particles are irradiated with ultraviolet rays, which are actinic rays, and the photocurable resin prepolymer is polymerized by excitation of the photosensitizer. , forming secondary particles.

The method described in JP-A No. 63-24886 is to obtain a granular carrier in which microorganisms are immobilized on a polyacrylamide gel. The liquid is dropped into an organic solvent from a nozzle in the form of droplets and gelled in the organic solvent.

That is, a hydrophobic organic solvent is used to make the suspended aqueous solution into droplets, and the organic solvent and the droplets are moved during continuous production, and when gelatinized, the granular gel is transferred to the organic solution Wc layer. It is taken from.

The method described in JP-A-60-153794 is to obtain a granular carrier in which microorganisms are immobilized on a polyacrylamide gel. A turbid water solution is dropped into an aqueous solution of calcium salt or aluminum salt in the form of droplets, the primary particles formed are transferred into an organic solvent, and acrylamide is polymerized to obtain a spherical gel.

[Problem to be solved by the invention]

The method described in JP-A-59-11182 requires the addition of a special substance, that is, a natural polysaccharide, to make the photocurable resin prepolymer spherical and gelatinous.

In addition, in this method, particle formation and polymerization are separate steps,
The process is complicated.

The method described in JP-A-63-24886 is as follows:
It is necessary to use an organic solvent that is harmful to microorganisms. In order to reduce this drawback, it may be possible to use edible oil in place of some or all of the organic solvent, but in this case, the oil will adhere to the surface of the resulting carrier particles and must be completely removed. It is difficult to do so.

The method described in JP-A-60-153794 is different from JP-A-63-24886 in that sodium alginate is added to form 1-inch particles. That is, by replacing sodium alginate with calcium or aluminum, there is an alginine-11 skin pancreas. Thus, it is necessary to use organic solvents that are harmful to microorganisms. Further, in this method, particle formation and polymerization are separate steps, and the steps are multiple zF.

In addition, as a method for granulating natural polymer gel, JP-A No. 62-1
No. 95284 discloses a method for granulating alginate,
It describes a method that is different from conventional methods. That is, this is a granulation method in which a microbial suspension containing calcium ions is dropped into an aqueous sodium alginate solution to form a film of calcium alginate.

According to this, granulation is easy, but when used for wastewater treatment, there is a problem that calcium ions are released by the phosphate ions contained and the gel collapses.

As described above, conventional methods for obtaining microorganism-immobilized carriers in particulate form have problems such as the need for organic solvents that are unfavorable for microorganism-immobilized carriers, complicated processes, and poor durability. there were.

The present invention is free from such drawbacks and provides a method for producing a granular gel carrier in which microorganisms are immobilized on eight arches.

[Means to solve the problem]

The present invention provides a suspension aqueous solution containing a water-soluble polymerizable compound, one of a polymerization accelerator and a polymerization initiator thereof, colloidal silica, a gelling agent consisting of a salt of a divalent or higher metal, and a microorganism. was added dropwise to a mixed aqueous solution containing sodium alginate and the remaining one of the polymerization accelerator and polymerization initiator of the above polymerizable compound.

The present invention relates to a method for producing a microorganism-immobilized granular gel, characterized in that the polymerizable compound is polymerized within the formed droplets.

The resulting microorganism-immobilized granular gel entraps microorganisms.

The above-mentioned polymerizable compound may be one that undergoes radical polymerization with a redox polymerization agent to form a hydrophilic gel, and includes monofunctional monomers, polyfunctional monomers, unsaturated prepolymers, and the like. Examples of monofunctional seven-mers include acrylamide, methacrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, polyethylene glycol monomethacrylate, methoxypolyethylene glycol methacrylate, methoxypolyethylene glycol acrylate, glycerol monomethacrylate, etc. Examples of polyfunctional monomers include ethylene glycol dimethacrylate, ethylene glycol diacrylate, butanediol dimethacrylate, butanediol diacrylate, glycerol dimethacrylate, N,N'-methylenebisacrylamide, N,N'-diallyl-L-
There are tartaric acid diamide, triacrylic formal, etc., and unsaturated prepolymers include polyethylene glycol dimethacrylate, polyethylene glycol diacrylate,
Examples include those obtained by subjecting polypropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polyvalent esters of acrylic acid or methacrylic acid of polyvinyl alcohol, xylylene diisocyanate, polyethylene glycol and 2-hydroxyethyl methacrylate to a urethane reaction.

Among the water-soluble polymerizable compounds having an unsaturated group as described above, monofunctional heptamers do not have three-dimensional bridge formation even if only they are made into polymers, resulting in gels with poor shape retention. Monofunctional monomers are therefore used together with polyfunctional monomers. The polyfunctional monomers and prepolymers may be used alone or in combination.

The polymerization agent is a redox polymerization agent consisting of a polymerization initiator and a polymerization accelerator. Redox polymerization agents include calcium persulfate-dimethylaminopropionitrile, potassium persulfate-sodium hydrogen sulfite, ammonium persulfate-sodium hydrogen sulfite, ammonium persulfate-sodium thiosulfate, hydrogen peroxide-ferrous chloride, and peroxide. There are combinations such as ascorbic acid and potassium persulfate and hydrazine.

The microorganisms include Bacteria, Fungi + Protozoa.
, metazoa], blue-green algae, and activated sludge consisting of a mixture of these, and may be aerobic or anaerobic bacteria.

Examples of the gelling agent made of a salt of a divalent or higher-valent metal include calcium chloride, calcium nitrate, aluminum chloride, aluminum sulfate, and aluminum nitrate, and these may be used in the form of hydrates.

These serve as gelling agents for colloidal silica and sodium alginate. Calcium chloride is preferred as the gelling agent in view of its low inhibitory effect on microorganisms.

Sodium chloride is added to the above divalent or higher metal salt.

A monovalent metal salt such as potassium chloride may be used in combination. However, the -valent metal salt only functions as a gelling agent for colloidal silica.

The colloidal silica is added for the purpose of solidifying the droplets so that they do not disperse and break when the suspended aqueous solution is dropped into the mixed aqueous solution containing sodium alginate, and gelling them into particles (particularly spherical shapes). It is something. That is, colloidal silica instantly gels with a divalent or higher valent metal salt to form a viscous precipitated gel. Therefore, the entire liquid in the above-mentioned G turbid aqueous solution becomes a viscous suspension.

When the suspension aqueous solution is dropped into a mixed aqueous solution containing sodium alginate and the remaining one of the polymerization agents of the polymerizable compound, it forms droplets that are strong enough not to disperse or become irregularly shaped, and to form droplets on the surface of the droplets. At the same time that an insoluble gel film of alginate is formed, one of the polymerizing agents in the mixed aqueous solution diffuses and permeates, and the polymerizable compound is polymerized inside the droplet together with the other polymerizing agent. be. Colloidal silica can also be expected to have the following effects:

When forming a hydrophilic synthetic polymer gel, if the concentration of the polymerizable compound in the suspended aqueous solution is too low, the mechanical strength of the gel will be low, and conversely, if the concentration is too high, the gel will have a dense matrix. It tends to decrease due to substance permeability. For this purpose, the degree of polymerizable monomer needs to be determined to adjust the mechanical strength and substance permeability of the gel, but by having a precipitated gel from colloidal silica in the gel, this can be achieved. Adjustment can be made easier.

When a polymerization accelerator and a polymerization initiator are simultaneously present in the W15 aqueous solution (the redox polymerization agent contains microorganisms), radical polymerization is immediately initiated and gelation progresses. Therefore, it gels during the step of dropping it into a sodium alginate aqueous solution, making it difficult to form droplets.

As a measure against this pot life, j? This problem can be solved by adding either a polymerization accelerator or a polymerization initiator to the turbid water solution, and adding the remaining one to the aqueous solution containing sodium alginate.

Next, the composition ratio of the aqueous suspension will be explained.

When using a monofunctional hexamer as a polymerizable compound,
It is generally used in an amount of 5 to 30% by weight based on the aqueous suspension, and in this case, the polyfunctional monomer used as a crosslinking agent is generally used in an amount of 0.5 to 5% by weight. If both of these are too small, the gel strength tends to decrease, making it difficult to maintain the shape as a carrier. Moreover, if these amounts are too large, the gel strength increases, but the permeability of substances within the gel decreases, so that reaction efficiency (processing) tends to decrease. If no monofunctional monomer is used, the polyfunctional monomer is generally 5 to 30% by weight of the aqueous suspension.
Similarly to the above, too little amount tends to weaken the gel strength, while too much amount tends to reduce substance permeability. Unsaturated prepolymers are also often used in similar composition proportions as polyfunctional heptamers.

The amount of the redox polymerization agent is appropriately determined in consideration of the type of 7-mer, gel initiation time, etc. The aqueous suspension solution contains one of a polymerization initiator and a polymerization accelerator, which are components of the redox polymerization agent, and the amount of the polymerization initiator is 0.1 to 0.4% by weight relative to the aqueous suspension solution. %5 The polymerization accelerator is preferably contained in an amount of 0.2 to 0.8% by weight based on the aqueous suspension.

In contrast to the component of the redox polymerization agent contained in the aqueous suspension solution, the other component is contained in the mixed aqueous solution containing sodium alginate, and the polymerization initiator is added in an amount of 0.1 to 5 times higher relative to the mixed aqueous solution. %, and the polymerization accelerator is preferably contained in an amount of 0.2 to 5% by weight based on the mixed aqueous solution.

The microorganisms are used in an appropriate amount, but preferably in an amount of 0.5 to 3% by weight (in the case of activated sludge, expressed as MLSS) based on the suspended aqueous solution.

Colloidal silica is used at a silicon dioxide content of 1 to 20% by weight based on the suspended aqueous solution; if this is too small, droplets may be dispersed in the mixed aqueous solution containing sodium alginate, or even if they are not dispersed, the droplets may remain. The shape of the gel becomes amorphous and the shape of the gel is similarly amorphous and difficult to form into clean particles. As for the shape, a spherical shape can be said to be the best shape considering wear resistance.

If there is too much colloidal silica, the polymerization reaction of the polymerizable compound may be suppressed, and the strength of the resulting gel may decrease. If this amount is too small, the droplet will drop into a mixed aqueous solution containing sodium alginate, and the alginate gel film will not be formed on the surface of the droplet, causing the droplet to disperse and gel in an irregular shape. Alternatively, a granular gel may not be obtained.

Sodium alginate is commercially available with seed properties ranging from low viscosity to high viscosity, but it is preferably used in an amount of 0.2 to 2% by weight. If the amount is too small, the formation of a gel film of alginate on the surface of the droplets of the suspended aqueous solution will be weak.
The gel shape of the formed microorganism-immobilized gel becomes amorphous, or the droplets become dispersed. If the amount is too high, the viscosity of the mixed aqueous solution will increase, causing droplets to stick to each other, the alginate gel film will become thicker, and when the microorganism-immobilized gel is taken out, a large amount of alginic acid will be taken out, resulting in wasted amount. is large.

The gelling agent of the present invention has a metal content of 0.3 to 6% by weight in the case of a divalent metal salt, and a trivalent metal content of 0.3 to 6% by weight based on the total amount of silicon dioxide in the colloidal silica and metal content in the gelling agent. In the case of metal salts, the metal content is preferably 0.1 to 3% by weight. The gelling agent of the present invention is added in an amount sufficient to gel the colloidal silica in the wIi aqueous solution to produce a precipitated gel;
In this case, when the S cloudy aqueous solution is dropped into a mixed aqueous solution containing sodium alginate, a gel film of the algine m salt is effectively formed on the surface of the droplet. The gelling agent of the present invention may be used in combination with a monovalent metal salt, but the gelling agent of the present invention is used in an amount sufficient to form the above-mentioned alginate gel film, and in some cases, the gelling agent of the present invention may be used in combination with a monovalent metal salt. The amount of gelling agent can be reduced compared to when only one gelling agent is used.

Next, the steps of the manufacturing method of the present invention will be explained.

The aqueous suspension solution may be prepared by mixing the components in any order, but first dissolve the monopolymerizable compound in water, add colloidal silica, and stir well. Colloidal silica is alkaline, so it is preferable for microorganisms. If not, a pH1ffi agent may be added in advance to adjust the pH to around neutrality), then a polymerization accelerator for one of the polymerization agents (
microorganisms (it is preferable to use their concentrated solution for activated sludge), suspend them well, add roughly divalent or higher metal salts, and if necessary further monovalent metals. It is preferable to add the salt (which may be used in the form of an aqueous solution) and stir well.

At this time, the colloidal silica immediately gels, and the entire liquid becomes a viscous suspended aqueous solution containing microorganisms.

Separately, a mixed aqueous solution of sodium alginate and the remaining polymerization initiator (or polymerization accelerator) is prepared.

The above mixed aqueous solution is stirred using a magnetic stirrer or the like, and the above suspended aqueous solution is added dropwise thereto. Dropping can be carried out using a nozzle, perforated plate, etc. having holes of a suitable diameter according to the size of the granular gel.

The dropped aqueous suspension instantly turns into fine granular droplets surrounded by an alginate gel film.

At the same time, one of the polymerization agents in the aqueous solution containing sodium alginate diffuses into the droplet, and polymerization of one polymerizable compound begins. Stirring is preferably performed while the polymerizable compound is sufficiently polymerized. If one granular gel is then taken out, a microorganism-immobilized granular gel can be obtained.

Note that this granular gel is covered with a gel film of alginate, so when using it for wastewater treatment, it is recommended to remove this film with a phosphate buffer before use. This is because the wastewater contains a large amount of phosphate ions, which causes the alginate gel film to dissolve and separate into the wastewater. By the above operations, it is possible to easily produce a granular gel in which microorganisms are entrapped and immobilized in a composite gel consisting of a synthetic polymer gel and a precipitated gel of colloidal silica.

〔Example〕

Example 1 A granular carrier in which activated sludge was immobilized on polyacrylamide gel was prepared. The activated sludge concentrate was added to an aqueous solution in which the acrylamide monomer and N,N'-methylenebisacrylamide were dissolved and mixed well. Dimethylaminopropionitrile (hereinafter abbreviated as DMAPN), a 5% by weight aqueous solution, as a polymerization accelerator was added to this. Colloidal silica [Snowtex-40 (Nissan Chemical Industry Co., Ltd.) was added to this suspended aqueous solution.
Two types were prepared, one with and without the addition of Calcium chloride dihydrate, and mixed well. If colloidal silica is present, a silica precipitate gel is immediately generated.

The entire liquid became a viscous suspension. In the case where colloidal silica was not present, the viscosity was low due to only the viscosity of activated sludge. Separately, sodium alginate (manufactured by SIGMA, N
A mixed aqueous solution consisting of potassium persulfate (hereinafter referred to as KzSzOg) as a polymerization initiator was prepared. However, with respect to the obtained suspension aqueous solution, 18% by weight of acrylamide monomer, 1% by weight of N,N'-methylenebisacrylamide, 2% by weight of activated sludge, DM
AP No., 5% by weight. Colloidal silica was added in an amount of 7.6% by weight based on silicon dioxide, and calcium chloride dihydrate was added so that the calcium content was 5% by weight based on the total amount of silicon dioxide and calcium.

Also, the amount of sodium alginate in the mixed aqueous solution obtained was 0.
．． 8% by weight and 42% by weight of KzSzOa.

The suspended aqueous solution was poured into a glass dropper (diameter I ohm).
The above-mentioned mixed aqueous solution was dropped drop by drop using a magnetic starter.

In the case where colloidal silica was present, the droplets instantly became spherical with a calcium alginate gel film, and were left under stirring for 10 minutes. Thereafter, the spherical gel taken out was a whitish-brown gel covered with a transparent layer of calcium alginate gel film. This was added to an aqueous phosphate buffer solution and stirred for 10 minutes to dissolve the calcium alginate gel film.

When we cut this whitish brown spherical gel and observed the inside, we found that
An activated sludge-fixed spherical gel was obtained which was sufficiently gelled and was comprehensively fixed in a composite gel consisting of polyacrylamide gel and colloidal silica precipitation gel. The diameter of the spherical gel was approximately 3.5ml.

On the other hand, for those who do not have colloidal silica.

Some of the droplets were dispersed into the mixed aqueous solution, and the liquid became cloudy. The remaining droplets gelled, but did not become spherical, but instead became irregularly shaped particles.

A granular carrier with activated sludge fixed thereon was prepared. Polyethylene glycol dimethacrylate [23G Shin Nakamura Chemical Industry (
Activated sludge concentrate was added to an aqueous solution in which the product was dissolved, and the activated sludge concentrate was mixed well. This is added to the polymerization accelerator DMAPN (5
wt% aqueous solution) was added. Two types were prepared with and without colloidal silica (Snowtex 40) added to this suspended aqueous solution, and calcium chloride dihydrate was added to both and mixed well. A silica precipitate gel was immediately formed, and the entire liquid became a viscous suspension. In the case where colloidal silica was not present, the viscosity was only that of activated sludge and was less viscous. Separately, sodium alginate and polymerization initiator KzS
A mixed aqueous solution consisting of 206 was prepared.

However, with respect to the suspension aqueous solution obtained above, 10% by weight of polyethylene glycol dimethacrylate and 2% of activated sludge were added.
DMAPN0.5% by weight. Colloidal silica was added in an amount of 7.6% by weight based on silicon dioxide, and calcium chloride dihydrate was added so that the calcium content was 5% by weight based on the total amount of silicon dioxide and calcium. In addition, 0.8% by weight of sodium alginate and 2% by weight of KzSZ○6 bed were added to the mixed aqueous solution obtained above.

The suspended aqueous solution was dropped drop by drop using a glass dropper (diameter 1 mm) onto the mixed aqueous solution being stirred with a magnetic starter.

The following procedure was carried out in the same manner as in Example 1. As a result, the gel containing colloidal silica became a spherical gel, and after removing the calcium alginate gel film with a phosphate buffer, the inside was observed, and it was found that the gel had sufficiently gelled. An activated sludge-fixed spherical gel was obtained which was comprehensively fixed in a composite gel consisting of a white-brown polyethylene glycol dimethacrylate gel and a precipitated gel, and the diameter of the spherical gel was about 2.8 mra.

On the other hand, for those who do not have colloidal silica.

Some of the droplets were dispersed into the mixed aqueous solution, and the liquid became cloudy. The remaining droplets gelled, but became irregularly shaped particles with a spherical shape.

Example 3 Activated sludge r fixation gel was produced in the same manner as in Example 1 or Example 2. However, as for the suspended aqueous solutions of each composition containing activated sludge, only those in which colloidal silica was present were tested. In addition, 2S20δ (using 2.5% by weight aqueous solution) was used as a polymerization initiator instead of the polymerization accelerator D M A P N.
was added to the aqueous suspension. Therefore, the polymerization accelerator DMAPN was added to the mixed aqueous solution instead of the polymerization initiator KzSzOs. The amount of 2S20♂ in the pre-suspension aqueous solution was 0.25% by weight, and the other compositions were the same as in Example 1 or Example 2.

The alginic acid concentration in the mixed aqueous solution is 0.8% by weight,
D MA P N was added in an amount of 2% by weight.

A glass dropper (diameter 1mm
) was used to drop the mixed aqueous solution drop by drop onto the area being stirred with a magnetic stirrer. Example 1 below
I did the same thing.

As a result, good spherical gels in which activated sludge was entrapped and fixed were obtained in both cases of using acrylamide monomer and polyethylene glycol dimethacrylate monomer. The diameter of the spherical gel after removing the calcium alginate gel film with the phosphate buffer solution was about 31 mi+ when using the aliclamide monomer, and about 2.7 mi+ when using the polyethylene glycol dimethacrylate monomer.

Test Example 1 Activated sludge fixed spherical gel obtained in Example 1 and Example 2
5.3 g each of the activated sludge-fixed spherical gel obtained in
h) was measured according to the sewerage test method. The spherical gel was used for measurement after being acclimated with synthetic sewage for 3 days.

As a result of measuring the same number of spherical gels (230 pieces), the oxygen utilization rate obtained in Example 1 was 28a+
g-02/Q-h, Example 2 is 3Qmg-0
2/Qh.

Test Example 2 5% by weight of DMA was added to a mixture of colloidal silica (Snowtex 40) and polyethylene glycol dimethacrylate with water added to an appropriate concentration.
After adding a PN aqueous solution and mixing well, a calcium chloride aqueous solution (calcium chloride 1 degree 10 w/v%) was added and well stirred. When the 6 colloidal silica gelled, it became a viscous precipitated gel. A 2.5% by weight potassium peroxide aqueous solution was added to this to prepare a final mixed solution, which was thoroughly stirred and then immediately placed in a cylindrical tube and allowed to stand still. After the polyethylene glycol dimethacrylate polymerizes into a polymer aggregate gel, it is extruded from a tube with a diameter of 13 mm.
It was made into a pellet with a length of 15 mg+.

Using this pellet, the compressive fracture strength by Tensilon was measured. The results are shown in FIG.

The amount of colloidal silica used was 0% by weight and 4% by weight based on silicon dioxide based on the final mixed liquid.

In each case, the amount of polyethylene glycol dimethacrylate (monomer) used was 5% by weight, 10% by weight, and 15% by weight based on the T4 mixture. and 20% by weight. In these cases, calcium chloride has a ratio of 7.6 to silicon dioxide in colloidal silica.
% by weight (the ratio of calcium to the total amount of silicon dioxide and calcium in calcium chloride dihydrate was 2% by weight). Further, DMAPN and peramic potassium were used in amounts of 0.4% by weight and 0.2% by weight, respectively, based on the final mixed solution.

In FIG. 1, graphs 1, 2, 3 and 4 are.

Colloidal silica was added to silicon dioxide at 0% by weight, 4% by weight, 8% by weight, and 16% by weight, respectively.
The amount of polyethylene glycol dimethacrylate-1 (seven tsum) used (weight % relative to the final mixed solution) and compressive fracture strength (kg/am
2) is a graph showing the relationship with 2).

In Figure 1, the strength is clearly increased when silicon dioxide is added, compared to the homopolymer gel of polyethylene glycol dimethacrylate (graph 1), which has 0% silicon dioxide, and this effect is due to the addition of 1% silicon dioxide by weight.
As seen above (not shown). Furthermore, when silicon dioxide reaches the 16th economic downturn (graph 4), the effect is large where the amount of resin is small, but the effect is not significant when the amount of resin is large. This is because when the amount of silicon dioxide increases,
This is thought to be due to the suppression of multiple coatings of polyethylene glycol dimethacrylate.

〔Effect of the invention〕

According to the present invention, a spherical microorganism-immobilized granular gel can be obtained without using an organic solvent that is highly inhibiting to microorganisms, and with simple operations. Moreover, the obtained microorganism-immobilized granular gel has good strength.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the results of Test Example 2. Graph when 1...5iOzO%, 2...5iO
The graph when z・1%, the graph when 3...5iOz8%

Claims (1)

[Claims] 1. A water-soluble polymerizable compound, either one of its polymerization accelerator and polymerization initiator, colloidal silica, a gelling agent consisting of a salt of a divalent or higher metal, and a microorganism are mixed. The suspension aqueous solution made of the above is dropped into a mixed aqueous solution containing sodium alginate and the remaining one of the polymerization accelerator and the polymerization initiator of the above polymerizable compound, and the above polymerizable compound is polymerized within the formed droplets. A method for producing a microorganism-immobilized granular gel, characterized by: 2. The method for producing a microorganism-immobilized granular gel according to claim 1, wherein the content of silicon dioxide in the aqueous suspension is 1 to 20% by weight.