JP6468639B2 - Autonomous material and method - Google Patents

Description

  The present invention relates to an autonomous floatation material and an autonomous floatation method. More specifically, the present invention relates to a material that can autonomously float and sink in an aqueous medium such as water, and a method for autonomously floating and sinking a granular material using the material in an aqueous medium such as water.

  Many types of pollutants are released into the environment by daily life, industrial activities, and accidents. Water and soil contamination from highly toxic organic matter, metals, and radioactive cesium emitted from petrochemical factories, mine refineries, and nuclear power plants are causing water pollution and public health problems. In particular, at the Fukushima Daiichi NPS, contaminated water due to inflow of groundwater into the reactor building has increased and is stored in large tanks. Developing effective means for reducing the burden of contaminated water treatment is an urgent issue for decommissioning work.

The pollutants have different specific gravity, and there are various types such as those that float on the water surface, those that sink to the bottom of the water, and those that exist uniformly in the water. For example, crude oil floats on the water surface because its specific gravity is less than water. On the other hand, nitrobenzene sinks to the bottom of the water because its specific gravity is greater than that of water. Many metal ions such as Pb ²⁺ , Cd ²⁺ , and Cs ⁺ are water-soluble and exist uniformly in water. Thus, in order to efficiently adsorb various pollutants with different specific gravity, it is necessary to ensure sufficient contact time between the adsorbent and the pollutant. Is required. Moreover, no matter how excellent the adsorption capacity is, it is meaningless if the adsorbent cannot be recovered after adsorbing the contaminants. When adapting an adsorbent at an actual contaminated site, it is important to control the specific gravity of the adsorbent, and at the same time, a device for easily recovering the adsorbent is required.

  So far, several studies on adsorbents aimed at ease of recovery have been reported. For example, research aimed at simplifying the handling of fine powdered adsorbents by encapsulating adsorbents such as carbon nanotubes and DNA in alginate gels (Sone et al., 2009 (non-patented) Literature 1)). In addition, magnetic separation of adsorbent using magnetite (Kuen and Mooney., 2012 (Non-patent Document 2)), drug delivery system (ICKwon et al., 1991 (Non-patent Document 3)) and nanobubbles (Takahashi et al. , 2007 (Non-patent Document 4)), there are also examples of research aimed at collecting contaminants by flotation separation. However, all reports are difficult to recover materials and to sustain the supply of chemicals and gases that serve as contaminant carriers.

  The inventors of the present invention have attempted to develop an adsorbing material that secures a contact time with a pollutant existing in the bottom of the water or water by controlling the specific gravity of the entire adsorbent and finally floats on the water surface. As a prototype, we introduced both “weight” and “float” into the alginate gel beads of the polysaccharide gel, and by adjusting these quantitative relationships, the adsorbent that stays at the bottom of the water for a certain period of time and then floats up. The development was reported (Mihara and Tanaka., 2013 (non-patent document 5)).

H. Sone, B. Fugetsu, S. Tanaka: "Selective elimination lead (II) ions by alginate / polyurethane composite foams" Journal of Hazardous Materials 162. 423-429 (2009). K. Y. Lee, D. J. Mooney: "Alginate: properties and biomedical applications" Progress in Polymer Science 37, 106-126 (2012). I.C. Kwon, Y.H. Bae, S.W. Kim: "Electrically erodible polymer gel for controlled release of drugs" Nature, 354, 291-293 (1991). M. Takahashi, K. Chiba, P. Li: "Formation of Hydroxyl Radicals by Collapsing Ozone Microbubbles under Strongly Acidic Conditions" J. Phys. Chem. B, 111-39, 11443-11446 (2007). Y. Mihara and S. Tanaka: "Development of a new type of adsorbent that can be collected easily on the surface of water after adsorption at the bottom of water" Journal of Environmental Chemistry, 23, 187-194 (2013).

The adsorbent described in Non-Patent Document 5 uses CaCO ₃ as a “weight”, encapsulates the powder in alginate gel beads, and dissolves the CaCO ₃ in water, so that the residence time of the gel beads at the bottom of the water and the surface rise to the water surface. We tried to control the time and the change of specific gravity over time. In this study, alginate gel beads with adsorption ability are transferred to the bottom of the water (the specific gravity is increased by CaCO ₃ introduced into the beads), and then adsorbed and floated on the water surface by the buoyancy of carbon dioxide bubbles contained in the beads. This makes it possible to remove pollutants deposited on the bottom of the water (lake bottom, sea bottom, etc.) and facilitate the recovery of the pollutants on the water surface.

  The adsorbent is a completely novel technology that is expected to be applied to on-site environmental purification. However, it has a weak point that it can be applied only under weakly acidic conditions where calcium carbonate can be dissolved. The adsorbent did not settle again once it floated from the bottom of the water, and could not continuously adsorb substances in the water while repeating ups and downs.

  Therefore, the present invention provides an autonomous floatation material that can be used in a wide range of water or aqueous solutions and aqueous media and does not need to be weakly acidic, and can float and sink repeatedly as well as once, and this material is used. It is an object (object) to be solved to provide a method for autonomously floating and sinking a granular material in an aqueous medium such as water. Furthermore, this invention makes it the subject (object) which should also be solved to provide the material and adsorption method which can adsorb | suck the substance in aqueous media, such as water, using the said material and method continuously.

In order to solve the above-described problems, the present inventors have come up with the idea that a new adsorbent can be developed based on the floating principle of CO ₂ generated by fermentation by introducing a fermentation process into the gel beads. When a gel bead that actually introduced a fermentation system was prepared and a floating experiment was conducted, the gel bead that had settled once floated on the water surface due to the carbon dioxide generated by the fermentation. In addition, a unique phenomenon (to be referred to as vertical migration), which has not been reported so far, was observed that the gel beads that floated settled again and repeated, and the present invention was completed.

The present invention is as follows.
[1]
In the matrix of the matrix forming material, microorganisms and / or micro-organisms that generate gas and / or aqueous medium-insoluble liquid by biological activity, and the microorganisms and / or micro-organisms assimilate to generate gas and / or aqueous medium-insoluble liquid. The composition used for the autonomous floatation in an aqueous medium containing the substance to do.
[2]
The composition according to [1], wherein the matrix forming material is (1) a low molecular (physical) gel, (2) a polymer chain (hydro) gel, or (3) a synthetic polymer compound.
[3]
The composition according to [1] or [2], wherein the microorganism and / or micro-organism generates carbon dioxide gas, oxygen gas, hydrogen gas, nitrogen gas, and / or methane gas as a gas by biological activity.
[4]
The composition according to any one of [1] to [3], wherein the microorganism and / or the micro-organism generates a hydrocarbon compound as an aqueous medium insoluble liquid by biological activity.
[5]
The microorganism and / or micro organism is at least one microorganism and / or micro organism selected from the group consisting of yeast, enterobacteria, lactic acid bacteria, aerobic spore bacteria, anaerobes, mold, algae, and plankton. The material according to [4].
[6]
The material according to any one of [1] to [5], wherein the microorganism is a yeast, and the substance that is assimilated by the microorganism to generate a gas is a sugar.
[7]
The material according to any one of [1] to [6], further comprising water in a matrix of the matrix forming material.
[8]
The material according to any one of [1] to [7], further comprising a weight substance in a matrix of the matrix-forming material, wherein the weight substance has a specific gravity greater than that of the material excluding the weight substance. .
[9]
1 part by weight of a matrix forming material contains 0.01 to 10 parts by weight of microorganisms, 0.1 to 1000 parts by weight of the microorganisms assimilated to produce gas, and 1 to 10,000 parts by weight of water. The material according to any one of [1] to [8].
[10]
The material according to any one of [1] to [9], further comprising an adsorbent, a feed, a pharmaceutical agent, an ion exchanger, a light emitter, a magnetic substance, a living organism, a cell, and / or a sensor.
[11]
[1] A molded article made of the material according to any one of [10].
[12]
The molded product according to [11], wherein the molded product is a granular product, a spherical product, a spherical product, a disk-shaped product, a sheet-shaped product, a columnar product, a tubular product, or a fibrous product.
[13]
[11] A method in which the molded product according to [12] is added to an aqueous medium so as to autonomously float and sink in the aqueous medium, provided that the specific gravity of the molded product is larger than that of the aqueous medium.
[14]
The method according to [13], wherein the specific gravity of the molded product is in a range of 1.05 to 1.8 times that of the aqueous medium.
[15]
The method according to any one of [13] to [14], wherein the molded product is stored refrigerated or frozen before being added to an aqueous medium.
[16]
The molded article is made of a material containing an adsorbent and / or an ion exchanger, and adsorbs and / or ion-exchanges a substance to be adsorbed in an aqueous medium during autonomous floatation in the aqueous medium. [15] The method according to any one of [15].
[17]
The molded product is separated and recovered from the aqueous medium after or after the autonomous floatation in the aqueous medium, and the adsorbent and / or ion exchanger adsorbing the substance to be adsorbed is recovered [16]. The method described in 1.
[18]
The molded article is made of a material containing feed and / or a pharmaceutical agent, and is preyed on by fish in the aqueous medium during the autonomous floatation in the aqueous medium to supply the fish and feed and / or pharmaceutical agent. [13] The method according to any one of [15].

  The vertical migration behavior of this gel bead is a new adsorbent material that can efficiently adsorb substances existing in the bottom of the water or in the water by repeated active vertical movement of the adsorbent material, and finally float and recover on the water surface. Leading to the development of For example, if there is a contaminant in a pond or large tank that is difficult to stir, if an adsorbent with a vertical migratory function is introduced, the adsorbent adsorbs the contaminant while moving back and forth between the bottom and the water surface, and finally on the water surface If it floats, the adsorbent material after adsorbing the pollutants can be recovered relatively easily.

The schematic explanatory drawing of the adsorption process of the contaminant in water by the adsorbent which has a vertical migratory function. The time course (glucose concentration dependence) of the sedimentation of one alginate gel bead in Example 2 is shown. From the top, glucose concentration is 5wt%, 10wt%, 30wt%. The time course (temperature (water temperature) dependence) of one alginate gel bead and the number of floats and sinks in Example 2 (the number of floats and sinks up to 12 hours after charging) is shown. Glucose concentration: 10 wt%, water temperature, 15 ° C, 20 ° C, 25 ° C and 30 ° C from the top. Observation (25 ° C) of vertical migration of alginate gel beads with fermentation system. The horizontal axis is time. The removal result of the cesium ion in the solution by the vertical migration of Prussian blue inclusion alginate gel beads in Example 4 is shown. (◆ Vertical migration (present invention), ■ Floating, ▲ Bottom settling) FIG. 5 shows photographs of floating (top) and bottom sediment (bottom) showing the results of the removal experiment.

<Composition>
The present invention relates to a composition used for autonomous floatation in an aqueous medium. This composition is generally referred to as a gas and / or an aqueous medium insoluble liquid (hereinafter referred to as a gas or the like) due to biological activity in the matrix of the matrix-forming material. Containing microorganisms and / or micro-organisms (hereinafter sometimes collectively referred to as microorganisms, etc.), and substances (hereinafter referred to as assimilation substances) that are produced by the microorganisms and that produce gases. To do.

  The matrix-forming material may be any material that can contain the microorganisms and the assimilating substance in the matrix of the matrix-forming material, and more specifically, the microorganisms and the assimilating substance are contained in the matrix for a certain period of time. Any material can be used as long as it can hold the gas and the gas generated by microorganisms or the like can be moved out of the matrix.

  As will be described further below, the matrix material can further contain water, so that the matrix material can hold microorganisms and assimilation substances present together with water in the matrix for a certain period of time, and through the water. Any material can be used as long as it can move gas generated by microorganisms or the like out of the matrix.

  From such a viewpoint, the matrix-forming material preferably forms a matrix and is a relatively hydrophilic material. For example, (1) low molecular (physical) gel, (2) high molecular chain (hydro) gel Or (3) a synthetic polymer compound, or a mixture thereof. However, the matrix forming material is not intended to be limited to these materials.

(1) Examples of low molecular (physical) gels include: fatty acid: natural fat fatty acid, 12-hydroxystearic acid, ionic liquid / polydimethylsiloxane (IL / PDMS): silicone gel, β-lactoglobulin gel, hyaluronic acid And at least one gel selected from the group consisting of chitosan, carboxymethylcellulose, polylactic acid, polyethylene glycol, and silica gel.
(2) Examples of polymer chain (hydro) gels include alginic acid, polymethacrylic acid, hydroxyethyl methacrylate, polyacrylamide: poly (N-isopropylacrylamide), polyvinyl methyl ether, polyrotaxane, hydroxyethyl methacrylate, gelatin There may be mentioned at least one gel selected from
(3) The synthetic polymer compound is, for example, a superabsorbent resin or an ion exchange resin,
Examples of the monomer (raw material) constituting the superabsorbent resin include N, N-dimethylacrylamide and N-vinylpyrrolidone, and examples of the monomer (raw material) constituting the ion exchange resin include styrene and divinylbenzene.

  There are no particular limitations on the biological activity of microorganisms that generate gas etc., such as metabolism, decomposition or photosynthesis of microorganisms, etc., and gas such as carbon dioxide gas (carbon dioxide gas), oxygen gas, hydrogen gas, nitrogen gas, methane gas and / or There is no particular limitation as long as it generates an aqueous medium-insoluble liquid (for example, a hydrocarbon compound). Microorganisms and / or micro-organisms that generate gas by biological activity are, for example, at least one selected from the group consisting of yeast, enteric bacteria, lactic acid bacteria, aerobic spore bacteria, anaerobes, molds, algae, and plankton. Mention may be made of microorganisms. Yeast, enterobacteria, and lactic acid bacteria produce carbon dioxide mainly as a gas by fermentation. Some aerobic spore bacteria and anaerobic bacteria produce carbon dioxide gas and hydrogen gas mainly as gases by fermentation. (Ii) Mold decomposes starch (which can be an assimilation substance or weight) by saccharification to produce carbon dioxide. Algae generates oxygen gas by photosynthesis. Cyanobacteria, a kind of algae, may produce hydrogen gas. Algae belonging to the genus Aurantiochytrium produce hydrocarbons (squalene = terpenoid oil) as an aqueous medium-insoluble liquid. The HD-1 strain (Oleomonas sagaranensis) also produces petroleum as an aqueous medium insoluble liquid under anaerobic conditions. Plankton produces carbon dioxide by breathing.

Microorganisms or the like that generate gas or the like by biological activity can be microorganisms belonging to the genus Saccharomyces shown below.
Saccharomyces bayanus
Saccharomyces boulardii
Saccharomyces bulderi
Saccharomyces cariocanus
Saccharomyces cariocus
Saccharomyces cerevisiae
Saccharomyces chevalieri
Saccharomyces dairenensis
Saccharomyces ellipsoideus
Saccharomyces florentinus
Saccharomyces kluyveri
Saccharomyces martiniae
Saccharomyces monacensis
Saccharomyces norbensis
Saccharomyces paradoxus
Saccharomyces pastorianus
Saccharomyces spencerorum
Saccharomyces turicensis
Saccharomyces unisporus
Saccharomyces uvarum
Saccharomyces zonatus

  It is preferable to use yeast (Saccharomyces cerevisiae) used in bread fermentation or alcohol fermentation, which is relatively easily available and has a high ability to generate carbon dioxide, as a microorganism.

Lactic acid bacteria mainly produce carbon dioxide (gas) by lactic acid fermentation at room temperature (15 ° C to 30 ° C) to produce lactic acid, acetic acid and the like. When a certain amount of lactic acid bacteria accumulates in the matrix, product accumulation is observed.
(Ii) Molds grow easily even at relatively low temperatures (5 ° C or higher). By the growth in the matrix, the starch (assimilable substance) is saccharified to produce carbon dioxide. For this reason, the matrix can float by decreasing specific gravity or volume expansion.
Algae can accumulate (carbon dioxide, oxygen gas, or hydrogen gas) or hydrocarbons in the matrix by photosynthesis or respiration at room temperature (15 ° C. to 30 ° C.).
Plankton (an example of a micro-organism) produces carbon dioxide in the matrix by photosynthesis or feeding. For this reason, the matrix sinks to the bottom of the water or floats in the water. Its behavior is likely to change depending on various factors such as temperature, water depth, hydrostatic pressure, light, oxygen, salinity, etc., but it can be used in large water areas such as ponds, brackish waters and oceans.

  A substance (an assimilation substance) that is assimilated by microorganisms or the like to generate gas can be appropriately selected according to the type of the microorganisms. When the microorganism is a yeast, the assimilating substance is a sugar such as glucose. Alternatively, starch as a raw material for saccharides such as glucose and an enzyme that decomposes starch and purifies saccharides can be used in combination as an assimilating substance. The assimilating substance for lactic acid bacteria includes, for example, glucose, starch, and organic matter taken into the matrix from the outside. (Ii) The assimilating substance for mold includes solid organic substances such as starch and cellulose, or organic substances taken from the outside. It is desirable that mold (inoculum) is supported on solid organic matter. The assimilating substances for algae obtain organic acids, alcohols, vitamins, and nutrients from the outside world in the environment necessary for photosynthesis. Utilization substances for plankton obtain phytoplankton and nutrients from the outside world, such as the bottom of the water or water.

  In the present invention, the minimum assimilating substance can be contained in the matrix, and other substances existing in the aqueous medium (outside) can be used as the assimilating substance.

  The matrix of the matrix forming material further contains water. Water is used for biological activities such as microorganisms, and also serves to dissolve gas generated by microorganisms and transfer it to the surface of the matrix-forming material. Furthermore, water can also serve to mediate transport of external materials (including assimilable substances) into the matrix while retaining the assimilable substances.

  A weight substance may be further contained in the matrix of the matrix forming material. However, the weight substance has a specific gravity greater than that of the material excluding the weight substance. The specific gravity of the weight substance is not particularly limited as long as it is larger than the specific gravity of the material excluding the weight substance, and can be appropriately selected in consideration of the type of the matrix forming material, the amount of the weight substance that can be added to the matrix forming material, and the like. Specifically, the weight substance can be calcium carbonate, magnesium carbonate, glucose, starch, glycerol, maltose and the like.

  The amount of assimilation substances and water contained in the matrix-forming material, such as microorganisms, is appropriately determined in consideration of the type of each material, the use of the molded product formed using the matrix-forming material of the present invention, and usage conditions. it can. Illustratively, 1 part by weight of the matrix-forming material contains 0.01 to 1000 parts by weight of an assimilating substance, such as 0.001 to 10 parts by weight of microorganisms, and 1 to 10,000 parts by weight of water. Can do. However, it is not intended to be limited to this range.

  The matrix-forming material of the present invention can contain various substances singly or in combination depending on the use of a molded product formed using the matrix-forming material of the present invention. Examples of substances that can be contained in the matrix-forming material of the present invention include, for example, adsorbents, feeds, pharmaceutical agents, ion exchangers, light emitters, magnetic bodies, organisms, cells, measurement elements (sensors), and the like. Can be mentioned. However, it is not intended to be limited to these substances.

<Molded product>
The present invention relates to a molded article comprising the matrix-forming material of the present invention. The shape, dimensions, etc. of the molded product can be appropriately determined according to the use of the molded product. The molded product of the present invention is, for example, a granular material, a spherical material, a disk-shaped material, a sheet-shaped material, a columnar material, a cylindrical material, a fibrous material (the cross section is circular, polygonal, hollow, etc.), etc. be able to. However, it is not intended to be limited to these shapes.

<Autonomous floating method>
The present invention relates to a method of adding a molded product made of the matrix-forming material of the present invention to an aqueous medium and allowing it to float and sink autonomously in the aqueous medium. However, the specific gravity of the molded product is larger than that of the aqueous medium in order to make it rise and fall autonomously in the aqueous medium. The specific gravity of the molded product is, for example, in the range of 1.05 to 1.8 times that of the aqueous medium, and the lower limit is preferably 1.06 times, more preferably 1.08 times, and even more preferably 1.1 times. is there. The upper limit is preferably 1.5 times, more preferably 1.3 times, and more preferably 1.2 times. However, it is not limited to this numerical range. It can be appropriately determined in consideration of the type and amount of microorganisms contained in the matrix-forming material, the period of autonomous floatation and the like.

  The type of the aqueous medium is not particularly limited. It may be water, an aqueous solution containing a solute, a dispersion containing a dispersoid, a dispersion aqueous solution containing a solute and a dispersoid, and the kind of solute and dispersoid is not particularly limited.

  The molded product is stored by refrigeration, freezing or lyophilization before addition to an aqueous medium. By being stored by refrigeration, freezing, or freeze-drying, it is possible to provide long-term storage and ease of carrying while suppressing metabolism of microorganisms and suppressing loss of gas generation ability.

  As an example of the autonomous flotation method of the present invention, the molded article is made of a material containing an adsorbent and / or an ion exchanger, and adsorbs a substance to be adsorbed in the aqueous medium during the autonomous flotation in the aqueous medium. And / or ion exchange methods.

  The molded article can be separated and recovered from the aqueous medium after completion of the autonomous floatation in the aqueous medium or during the autonomous floatation to recover the adsorbent and / or ion exchanger adsorbing the adsorbed substance.

  In the embodiment, as an adsorbing material having the above function, an adsorbing material having a vertical migratory property in which a fermentation system composed of yeast and glucose is introduced into alginate gel beads, and bubbles of carbon dioxide generated by fermentation are floated to repeatedly float and settle. showed that. The autonomous ups and downs of the alginate gel beads are schematically shown in FIG. Adsorbent materials that autonomously perform ups and downs can efficiently adsorb and recover pollutants such as water environments and large tanks that are difficult to stir, and the energy of the adsorbent itself by its active vertical migration. Almost no need. In addition, since it is not necessary to send contaminated water to the column filled with the adsorbent using a pump, there is no fear of water leakage from the pipe. Since it finally floats on the water surface, it has a feature that it can be recovered relatively easily on the water surface.

  As another example of the autonomous flotation method of the present invention, the molding is made of a material containing feed and / or a pharmaceutical agent, and is preyed on by fish in the aqueous medium during the autonomous flotation in the aqueous medium. And a method of supplying feed and / or pharmaceutical agents to fish.

  As another example of the autonomous floatation method of the present invention, the molded article is made of a material containing a light emitter and / or a magnetic material, and emits light or a specific portion by a chemical reaction or a stimulus from the outside during autonomous floatation in a water tank. Luminaires or toys that gather together.

  As another example of the autonomous floatation method of the present invention, the molding is made of a material including a sensor, and can record a physical or chemical change of an aqueous medium during autonomous floatation in a specific hydrosphere. Can be mentioned.

  Hereinafter, the present invention will be described in more detail based on examples. However, the examples are illustrative of the present invention, and the present invention is not intended to be limited to the examples.

Example 1
1) Manufacturing method A 1 wt% aqueous alginate solution was prepared by weighing 1.00 g of sodium alginate powder and adding 100 mL of distilled water. Weigh 0.75 g of sodium bicarbonate and 0.30 g of dry yeast, glucose in the range of 1.25 g, 2.50 g, or 7.50 g (5, 10, 30 w / w%), transfer them to a screw test tube, and stir and mix did. Next, a 1 wt% alginate aqueous solution was added to the screw-cap test tube in ice until the mass of the entire sample became 25 g, and then stirred so that the whole was well mixed. This solution was fed with a peristaltic pump and added dropwise to 100 mL of a 0.1 M aqueous calcium nitrate solution (pH 5.0, 5 ° C.) to produce alginate gel beads. When a nozzle having an inner diameter of 5.0 mm was used, about 125 alginate gel beads having a diameter of 5.0 ± 0.1 mm could be produced per 25 g of the sample. The specific gravity of the obtained alginate gel beads was 1.065, 1.092 and 1.162, respectively.

Example 2
The alginate gel beads prepared in Example 1 were tested for autonomous floatation.
Using a cylindrical container of 5-10 L (height 1-2 m), the change in the number of times the gel beads were floated and lowered with changes in glucose concentration and water temperature was measured.

  The result when the glucose concentration is changed is shown in FIG. When the glucose concentration was 5 (w / w%), the self-sustaining floatation time of the alginate gel beads depending on the glucose content was approximately 6 hours, whereas the glucose concentration was 10 (w / w%). 30 (w / w%), it was extended to about 12 hours and 48 hours.

The results when the water temperature is 15 ° C., 20 ° C., 25 ° C. or 30 ° C. are shown in FIG.
When the temperature condition was 20 ° C., the number of floats until 12 hours after dropping the alginate gel beads was 9 times. However, the number of ups and downs varied greatly depending on the water temperature. For example, the number of repetitions of ups and downs for 12 hours after dropping the gel beads at a water temperature of 15 ° C. was 4 times, which was less than at other water temperatures. The reason for this is that yeast ferments even at low temperatures. However, it is considered that the amount of carbon dioxide gas that changes the buoyancy of alginate gel beads is small. On the other hand, when the water temperature is 30 ° C, the activity of yeast increases, and the amount of carbon dioxide that changes the buoyancy of alginate gel beads increases, but the amount of carbon dioxide that accumulates in the gel also increases, so it floats on the surface of the water. The time that has been extended. For this reason, the activity of the yeast involved in glucose fermentation is optimized by temperature control in water, and also affects the number of floats and sinks of alginate gel beads.

  By changing the amount of glucose and yeast to be encapsulated and the water temperature, the amount of carbon dioxide generated in the gel and the generation time required for the floatation will also differ. By controlling these factors, the buoyancy of the gel beads is controlled. I was able to.

Example 3
Observation of morphology of gel beads with vertical migratory properties and analysis of fermentation rate constants In order to investigate whether gel beads repeatedly float and sink by introducing a fermentation system, the state of carbon dioxide accumulation inside alginate gel beads and on the water surface The state of the disappearance process of carbon dioxide on the gel surface was examined from observation with a microscope (FIG. 4).

  As a result of the above observation, it is considered that the mechanism of the vertical migration of the gel beads is as follows. The bubbles of carbon dioxide generated by the fermentation of glucose by yeasts initially remain inside the gel beads and act as floats, causing the gel beads to float. As the gel beads float, the water pressure is relaxed and the volume of carbon dioxide bubbles gradually increases, and some of the bubbles also emerge on the surface of the gel, but float while remaining attached to the gel beads. When the gel beads float on the water surface, the bubbles adhering to the surface of the gel beads are separated from the gel, so that the gel beads lose buoyancy and start to settle. While the fermentation continued, carbon dioxide bubbles were generated and the buoyancy caused the gel to rise again. By repeating this behavior, vertical migration is imparted to the gel beads. One gel bead floats and sinks as shown in FIGS. 1 and 2 shown in Example 2, and it can be observed that sedimentation and floating are repeated ten times or more. Finally, all the glucose was consumed, and the gel beads became light and floated on the water surface. The floated gel beads could be easily recovered on the water surface.

Example 4
Removal of cesium by Prussian Blue-encapsulated alginate gel beads In order to investigate the adsorption efficiency of cesium ions in vertical migration using Prussian blue-encapsulated alginate gel beads, alginate gel beads floating on the water surface (specific gravity <water) or in a submerged state ( The concentration change of the cesium ion in the solution was investigated as compared with the alginate gel beads having a specific gravity> water.

Preparation method of alginate gel beads containing Prussian blue:
(1) Method for producing Prussian blue-encapsulated alginate gel beads (specific gravity> water) (Comparative example): A 1 wt% aqueous alginate solution was prepared by weighing 1.00 g of sodium alginate powder and adding 100 mL of distilled water. 7.50 g (30 w / w%) of glucose and 125 mg of Prussian blue powder were weighed, transferred to a screw-cap test tube, and mixed with stirring. Next, a 1 wt% alginate aqueous solution was added to the screw-cap test tube in ice until the mass of the entire sample became 25 g, and then stirred so that the whole was well mixed. This solution was fed with a peristaltic pump and dropped into 100 mL of 0.1 M calcium nitrate aqueous solution (pH 5.0, 5 ° C.) to produce alginate gel beads (specific gravity 1.383) enclosing Prussian blue.

(2) Method for producing Prussian blue-encapsulated alginate gel beads (specific gravity <water) (Comparative Example): A 1 wt% aqueous alginate solution was prepared by weighing 1.00 g of sodium alginate powder and adding 100 mL of distilled water. 0.6 g of hollow glass beads (φ100 μm), 7.50 g (30 w / w%) of glucose and 125 mg of Prussian blue powder were weighed, transferred to a screw test tube, and mixed with stirring. Next, a 1 wt% alginate aqueous solution was added to the screw-cap test tube in ice until the mass of the entire sample became 25 g, and then stirred so that the whole was well mixed. This solution was fed with a peristaltic pump and dropped into 100 mL of a 0.1 M calcium nitrate aqueous solution (pH 5.0, 5 ° C.) to produce alginate gel beads (specific gravity 0.655) enclosing Prussian blue.

(3) Method for producing Prussian blue encapsulated alginate gel beads (having a vertical migration function) (the present invention):
The 1 wt% alginate aqueous solution was prepared by weighing 1.00 g of sodium alginate powder and adding 100 mL of distilled water. Sodium hydrogen carbonate 0.75 g, dry yeast 0.30 g, glucose 7.50 g (30 w / w%) and Prussian blue powder 125 mg were weighed and transferred to a screw test tube, followed by stirring and mixing. Next, a 1 wt% alginate aqueous solution was added to the screw-cap test tube in ice until the mass of the entire sample became 25 g, and then stirred so that the whole was well mixed. This solution was fed with a peristaltic pump and added dropwise to 100 mL of a 0.1 M calcium nitrate aqueous solution (pH 5.0, 5 ° C.) to produce alginate gel beads (specific gravity at the time of creation: 1.132).

  Cesium ion removal experiment in an aqueous dispersion: A sample was prepared by adding 100 grains of Prussian blue-encapsulated alginate gel beads to a cylindrical column containing 5 L of an aqueous solution prepared with a cesium ion concentration of 100 ppm. Water was collected from the middle and bottom of the column every time, and the change in the concentration of cesium ions was determined by atomic absorption spectrophotometry. The results are shown in FIG. A photograph in the case of floating (Floating (specific gravity <water)) is shown in FIG. 6, and a photograph in the case of bottom sedimentation (Bottom (specific gravity> water)) is shown in the lower part of FIG.

  In this example, alginate gel beads encapsulating Prussian blue, which has the ability to adsorb cesium, have a vertical migratory property, simply float on the surface, and simply stay on the bottom of the water. Alginate gel beads were placed in a water tank with about 1 meter, and the removal efficiency of cesium ions in water was compared (FIG. 4). As a result, it was found that the cesium ions can be removed sufficiently quickly with an adsorbent having a vertical migratory property as compared with an adsorbent that floats on the water surface and an adsorbent that only remains at the bottom of the water.

  Adsorbents with vertical migratory properties can be applied in various places in the hydrosphere. In particular, the power is exhibited in a place where it is difficult to use stirring or the column method. For example, in the removal of pollutants in water stored in a pond or a large tank, when the adsorbent developed by the present invention is introduced, the adsorbent actively adsorbs pollutants while moving around vertically in the water, and finally Since it floats on the surface of the water, it can be easily recovered using a net. Since neither a stirrer nor a pump is required, processing can be performed with almost no energy consumption.

  The present invention is useful for various applications that can float and sink autonomously in an aqueous medium.

Claims (20)

Microorganism and / or micro-organism that generates a hydrocarbon compound as an aqueous medium-insoluble liquid by biological activity in a matrix of a matrix-forming material that is (1) a low molecular (physical) gel or (2) a polymer chain (hydro) gel And a composition used for autonomous floatation in an aqueous medium, containing a substance that the microorganisms and / or micro-organisms assimilate to produce an aqueous medium-insoluble liquid. The composition of claim 1, further comprising a weight substance in a matrix of the matrix-forming material, wherein the weight substance has a specific gravity greater than the specific gravity of the material excluding the weight substance. The composition according to any one of claims 1 to 2, further comprising an adsorbent, a feed, a pharmaceutical agent, an ion exchanger, a light emitter, a magnetic substance, an organism, a cell, and / or a sensor. The molded article which consists of a composition of any one of Claims 1-3. The molded product according to claim 4, wherein the molded product is a granular product, a spherical product, a spherical product, a disk-shaped product, a sheet-shaped product, a columnar product, a cylindrical product, or a fibrous product. The polymer chain (hydro) gel contains microorganisms and / or micro-organisms that generate gas by biological activity and substances that are produced by the microorganisms and / or micro-organisms, and the generated gas is contained inside the gel beads. Gel beads used for autonomous floatation in an aqueous medium, which can be stored in a portion and a part of the accumulated gas can be discharged to the surface of the gel beads. The gel beads according to claim 6, wherein the polymer chain (hydro) gel is a gel prepared in the presence of water and sodium hydrogen carbonate. The gel beads according to claim 6 or 7, wherein the gel beads are used for repeated autonomous floatation in an aqueous medium, which repeats autonomous floatation at 15 ° C at least four times. The gel bead according to any one of claims 6 to 8, wherein the microorganism and / or micro-organism generates carbon dioxide gas as a gas by biological activity. The gel bead according to any one of claims 6 to 9, wherein the microorganism is a yeast, and the substance that is assimilated by the microorganism to generate a gas is a sugar. The gel beads according to any one of claims 6 to 10, further comprising a weight substance in the gel, wherein the weight substance has a specific gravity greater than a specific gravity of a material excluding the weight substance. 1 part by weight of gel-forming material contains 0.01 to 10 parts by weight of microorganisms, 0.1 to 1000 parts by weight of the microorganisms assimilated to produce gas, and 1 to 10000 parts by weight of water. The gel bead according to any one of claims 6 to 11. The gel beads according to any one of claims 6 to 12, further comprising an adsorbent, a feed, a pharmaceutical agent, an ion exchanger, a light emitter, a magnetic substance, a living organism, a cell, and / or a sensor. A method of adding the molded product according to claim 4 or 5 to an aqueous medium and allowing the molded product to float and sink autonomously in the aqueous medium, wherein the specific gravity of the molded product is larger than that of the aqueous medium. In a polymer chain (hydro) gel, gel beads containing microorganisms and / or micro-organisms that generate gas by biological activity and substances that are assimilated by the microorganisms and / or micro-organisms to generate gas are autonomous in an aqueous medium. A method for floating and sinking, wherein the autonomous floating and sinking comprises storing a gas generated by utilizing a substance in which the microbe and / or micro-organism in the gel bead generates a gas, and a part of the accumulated gas on the surface of the gel bead. In which the specific gravity of the gel beads is greater than that of the aqueous medium. The method according to claim 14 or 15, wherein the specific gravity of the molded product or gel beads is in the range of 1.05 to 1.8 times that of the aqueous medium. The method according to any one of claims 14 to 16, wherein the molded product or gel beads are stored refrigerated or frozen before being added to an aqueous medium. The molded article or gel bead includes an adsorbent and / or an ion exchanger, and adsorbs and / or ion-exchanges a substance to be adsorbed in an aqueous medium during an autonomous floatation in the aqueous medium. The method of any one of these. The molded product or gel beads are separated and recovered from the aqueous medium after or after the autonomous floatation in the aqueous medium, and the adsorbent and / or ion exchanger adsorbing the adsorbed substance is collected. Item 19. The method according to Item 18. The molded article or gel bead includes a feed and / or a pharmaceutical agent, and is preyed on by fish in the aqueous medium and supplies the fish and feed and / or pharmaceutical agent during the autonomous floatation in the aqueous medium. Item 20. The method according to any one of Items 14 to 19.