JP7588922B1 - Carbon dioxide fixation system, carbon dioxide fixation method, and carbon dioxide fixation program - Google Patents

Abstract

[Problem] To provide a carbon dioxide fixation system that promotes fixation of carbon dioxide in marine products during the biomineralization process for calcium carbonate production in marine products. [Solution] The carbon dioxide fixation system includes a proton removal device that removes protons from water in which marine products that produce calcium carbonate as part of themselves are present. [Selected Figure] Figure 1

Description

The present invention relates to a carbon dioxide fixation system, a carbon dioxide fixation method, and a carbon dioxide fixation program.

Among marine products, there are organisms that form their shells using carbon dioxide and calcium carbonate (hereinafter also referred to as _CaCO3 ) in the water. Among them, shellfish feed on phytoplankton that absorbs carbon dioxide through photosynthesis, and grow by absorbing elements such as carbon, hydrogen, and oxygen. Shells grow as shellfish grow, and are formed when calcium carbonate crystallizes carbon dioxide in the water using organic matter secreted by the shellfish as a substrate. In this way, shellfish are known to absorb carbon dioxide by forming shells using carbon dioxide and other substances in the water (see Non-Patent Documents 1 and 2).

WO2009/119846 Abstracts of the 55th Symposium on Natural Organic Compounds, published on March 19, 2018, p. Oral9, Takeshi Yasumoto et al. Tsuyoshi Yasumoto Journal of the Japanese Society of Fisheries Science, Vol. 88, No. 6, published November 15, 2022, p. 542 Ware, J R. et al., “Coral reefs: sources or sinks of atomospheric CO2?” Coral Reefs (1991) 11, p127-130 Marine Biological Research Institute News No. 99, July 2008, p2-4

On the other hand, there is a view that biomineralization by shellfish and other organisms does not lead to the fixation of carbon dioxide (Non-Patent Document 2).

To explain the reason for this view, if calcium ions (Ca2 ⁺ ) and bicarbonate ions ( _HCO3- ⁾ are present in water as the raw materials for calcium carbonate, the production of calcium carbonate ( _CaCO3 ) (calcification reaction, → direction in formula (1) below) produces hydrogen ions (H ⁺ , protons), lowering the pH. Then, as shown in formulas (1) and (2), the calcium carbonate that is formed becomes hydrogen carbonate ions (← direction in formula (1) below), and these hydrogen carbonate ions ( _HCO3- ⁾ react with hydrogen ions to form carbonic acid ( _H2CO3 ), which ultimately releases carbon dioxide ( _{CO2 )} into the water (→ direction in formula (2) below).

Ca ²⁺ + HCO ₃ ^- ⇔CaCO ₃ + H ⁺ ...Formula (1)
HCO ₃ ^- + H ⁺ ⇔H ₂ CO ₃ ⇔CO ₂ + H ₂ O...Formula (2)

In other words, as protons are produced, the carbon dioxide fixed in the shells is released back into the water, so carbon dioxide is not fixed in the shells.

In addition, it is said that the acidification of seawater, which has become a problem in recent years, inhibits the production of calcium carbonate (← direction in the following formula (3)) and promotes its dissolution (→ direction in the following formula (3)) (Non-Patent Document 3).
CaCO ₃ + CO ₂ + H ₂ O ⇔Ca ²⁺ +2HCO ₃ ^- …Formula (3)

Another issue is that even if carbon dioxide is fixed in algae, it is not possible to efficiently feed the algae to the seafood that feeds on it. As a result, biomineralization using carbon dioxide fixed by algae as a raw material has not been carried out efficiently.

The present invention has been made in consideration of the above points. Its purpose is to provide a carbon dioxide fixation system, a carbon dioxide fixation method, and a carbon dioxide fixation program that promote the fixation of carbon dioxide in marine products during the biomineralization process in the production of calcium carbonate in marine products.

The carbon dioxide fixation system according to the first aspect of the present invention includes a proton removal device that removes protons from water containing marine products that produce calcium carbonate as part of themselves.

The carbon dioxide fixation system according to the first aspect can promote fixation of carbon dioxide in marine products during the biomineralization process in the production of calcium carbonate in marine products.

In the carbon dioxide fixation system according to the first aspect, the marine product may be a shellfish, crustacean, or cnidaria.

This carbon dioxide fixation system can promote carbon dioxide fixation in seafood that produces shells and skeletons.

In addition, in the dioxide fixation system according to the first aspect, the proton removal device may be an electron generating device having an anode and a cathode.

This carbon dioxide fixation system recovers protons in the water, promoting the fixation of carbon dioxide in marine products. In the process, the bottom mud, which is a reductant, is converted into an oxidant, and the bottom mud is purified, which also purifies the mud at the bottom. Furthermore, with this carbon dioxide fixation system, the organic matter in the bottom mud is decomposed by the power-generating bacteria, and nutrients such as nitrogen are dissolved into the water, allowing microalgae to grow. The proliferated microalgae can also purify the water.

In addition, in the dioxide fixation system according to the first aspect, the proton removal device may be a deionization device.

This carbon dioxide fixation system can promote carbon dioxide fixation using commercially available ion exchange devices, membranes, and resins. In addition, this configuration can be installed while utilizing existing equipment. This makes installation easy. Replacement is also easy because commercially available items can be used.

In addition, in the dioxide fixation system according to the first aspect, the proton removal device may be installed in an aquaculture facility in which the marine products are present.

With this carbon dioxide fixation system, the proton removal device is installed within existing facilities, so there is no need to secure new installation space. Another advantage is that the proton removal device can be installed closer to the seafood.

In addition, in the dioxide fixation system according to the first aspect, the proton removal device may be connected to an aquaculture facility in which the marine product is present.

With this carbon dioxide fixation system, a proton removal device can be installed as a retrofit without changing the configuration of existing equipment. In this way, it is easy to introduce into existing equipment.

The dioxide fixation system according to the first aspect may further include a first water flow generating device that generates a water flow toward the proton removal device.

According to this carbon dioxide fixation system, by generating the desired water flow, protons can be removed and food can be delivered to the marine products more efficiently. This promotes carbon dioxide fixation in the marine products. Specifically, by having the water flow generating device generate a water flow toward the proton removal device, protons can be removed efficiently.

The dioxide fixation system according to the first aspect may further include a second water flow generating device that generates a water flow toward the marine product.

This carbon dioxide fixation system allows the seafood to efficiently ingest algae that exists in the same water and serve as food for the seafood, and the seafood can more efficiently fix the carbon dioxide absorbed by the algae. Furthermore, by making it easier for the seafood to ingest the algae that they feed on, the growth of the seafood is promoted, making it possible to cultivate high-quality seafood. Furthermore, this carbon dioxide fixation system allows the seafood to more efficiently fix carbon dioxide in the water.

The carbon dioxide fixation method according to the second aspect of the present invention includes the steps of placing a marine product that produces calcium carbonate as part of itself in water, and removing protons from the water.

The carbon dioxide fixation method according to the second aspect can promote fixation of carbon dioxide in marine products during the biomineralization process in the production of calcium carbonate in marine products.

The carbon dioxide fixation program according to the third aspect of the present invention includes a step of removing protons from water in which aquatic products that produce calcium carbonate as part of themselves are present.

The carbon dioxide fixation program according to the third feature can promote fixation of carbon dioxide in seafood during the biomineralization process in the production of calcium carbonate in seafood.

The fourth aspect of the present invention is an environmental purification system that includes a proton removal device that removes protons from water containing marine products that produce calcium carbonate as part of themselves.

The environmental purification system according to the fourth aspect can promote the fixation of carbon dioxide into marine products during the biomineralization process in the production of calcium carbonate in marine products.

In addition, in the environmental purification system according to the fourth aspect, the marine products may be shellfish, crustaceans, or cnidarians.

This environmental purification system can promote the fixation of carbon dioxide in seafood that produces shells and skeletons.

In addition, in the environmental purification system according to the fourth feature, the proton removal device may be an electron generating device having an anode and a cathode.

This environmental purification system recovers protons in the water and promotes the fixation of carbon dioxide in marine products. In the process, the bottom mud, which is a reductant, is converted into an oxidant, and the bottom mud is purified, so the mud at the bottom can also be purified. Furthermore, this environmental purification system decomposes organic matter in the bottom mud by the power-generating bacteria, and nutrients such as nitrogen are dissolved into the water, which allows microalgae to grow. The proliferated microalgae can also purify the water. In this way, this system is a comprehensive environmental purification system that not only promotes the fixation of carbon dioxide in marine products, but also simultaneously purifies the bottom mud and water.

The fifth aspect of the present invention relates to an environmental purification method that includes the steps of placing a marine product that produces calcium carbonate as part of itself in water, and removing protons from the water.

The fifth feature of the environmental purification method is that it is possible to promote the fixation of carbon dioxide into marine products during the biomineralization process in which calcium carbonate is produced in marine products.

According to this environmental purification method, protons in the water are collected and the fixation of carbon dioxide in marine products is promoted. In this process, the bottom mud, which is a reductant, is converted into an oxidant and the bottom mud is purified, so the mud at the bottom can also be purified. Furthermore, according to this environmental purification method, organic matter in the bottom mud is decomposed by the power-generating bacteria and nutrients such as nitrogen are dissolved into the water, which allows microalgae to grow. The proliferated microalgae can also purify the water. In this way, this method is a comprehensive environmental purification method that not only promotes the fixation of carbon dioxide in marine products, but also purifies the bottom mud and water at the same time.

The sixth aspect of the present invention relates to an environmental purification program that includes a step of removing protons from water containing marine products that produce calcium carbonate as part of themselves.

According to the environmental purification program relating to the sixth feature, the fixation of carbon dioxide into marine products can be promoted during the biomineralization process in the production of calcium carbonate in marine products.

According to this environmental purification program, protons in the water are collected and the fixation of carbon dioxide in marine products is promoted. In the process, the bottom mud, which is a reductant, is converted into an oxidant and the bottom mud is purified, so the mud at the bottom can also be purified. Furthermore, according to this environmental purification program, the organic matter in the bottom mud is decomposed by the power-generating bacteria and nutrients such as nitrogen are dissolved into the water, which allows microalgae to grow. The proliferated microalgae can also purify the water. In this way, this program not only promotes the fixation of carbon dioxide in marine products, but also allows the environmental purification system to carry out a comprehensive environmental purification method that simultaneously purifies the bottom mud and water.

The present invention provides a carbon dioxide fixation system, a carbon dioxide fixation method, and a carbon dioxide fixation program that promote the fixation of carbon dioxide in marine products during the biomineralization process in the production of calcium carbonate in marine products.

The present invention also provides an environmental purification system, method, and program that promote the fixation of carbon dioxide in marine products during the biomineralization process in which calcium carbonate is produced in marine products, and that purifies bottom mud and water.

FIG. 1 is a block diagram showing a carbon dioxide fixation system according to a first embodiment. FIG. 2 is a diagram showing an electron generating device used as a proton removing device according to the first embodiment. FIG. 1 is a diagram showing a case in which a deionization device is used as a proton removing device according to a first embodiment. 1 is a flowchart showing a carbon dioxide fixation method according to a first embodiment. FIG. 11 is a block diagram showing a carbon dioxide fixation system according to a second embodiment. 10 is a flowchart showing a carbon dioxide fixation method according to a second embodiment. FIG. 1 is a diagram showing a schematic diagram illustrating that the removal of protons has a proliferation effect on microalgae. FIG. 1 shows another embodiment 1 of proton removal. FIG. 13 is a diagram showing an example of use of a proton removing device equipped with a tetrapod-type electron generating device. FIG. 13 shows another embodiment 2 of proton removal. FIG. 1 is a diagram showing a carbon dioxide fixation technology using steel slag and marine products. FIG. 1 is a graph showing the promotion of microalgae growth by steel slag. FIG. 1 is a diagram showing an example of a carbon dioxide fixation system using steel slag. FIG. 3 shows another embodiment 3 of proton removal. FIG. 4 shows another embodiment 4 of proton removal. FIG. 13 is a diagram showing another example of use of the aquaculture cage. FIG. 5 shows another embodiment 5 of proton removal. 13A is a diagram showing another embodiment 6 relating to proton removal, FIG. 13B is a perspective view showing a negative electrode anchor, and FIG. 13C is a perspective view showing another form of the negative electrode anchor. FIG. 7 shows another embodiment 7 of proton removal. FIG. 8 shows another embodiment of proton removal.

<<<<First embodiment>>>>
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a block diagram showing a carbon dioxide fixation system 10 according to the first embodiment.

<<<Carbon Dioxide Fixation System 10>>>
The carbon dioxide fixation system 10 mainly comprises a proton removal device 200 that removes protons (H ⁺ ) from water containing aquatic products 100 that produce calcium carbonate (CaCO ₃ ) as part of themselves, and an aquaculture facility 300 .

<<100 Seafood Products>>
The marine product 100 according to this embodiment may be any product that produces a part of itself, such as its shell, by utilizing a calcification reaction that produces calcium carbonate (CaCO ₃ ) from carbon dioxide and calcium.

For example, calcium carbonate ( _CaCO3 ) produced by seafood includes the shells of mollusks, the exoskeletons of crustaceans, the skeletons of cnidarians (corals), the shells of invertebrates such as the protozoan foraminifera, and coccoliths produced by single-celled algae called coccolithophorids.

The marine products in this embodiment include shellfish, crustaceans, echinoderms (sea urchins), and cnidarians (corals), and more preferably shellfish.

Among shellfish, bivalve mollusks are particularly preferred.

Among bivalve mollusks, oysters, scallops, mussels, corbiculas, clams, and pearl oysters are particularly preferred.

The main types of oysters include Ostrea denselamellosa, Ostrea edulis (European flat oyster), Crassostrea gigas (Japanese oyster/Pacific oyster/Rock oyster), Crassostrea sikamea, Crassostrea ariakensis, Crassostrea nippona, Crassostrea angulata, Crassostrea virginica, Tiny Pacific oyster (Ostrea lurida), and Bluff oyster (Ostrea chilenesis).

<<Water>>
The water in which the seafood exists may be any water in which the seafood can survive. Examples include seawater, freshwater, brackish water, etc. The type of water depends on the type of seafood. It is preferable that the water contains carbon dioxide, as the seafood will fix the carbon dioxide in the water. The origin of this carbon dioxide is not important. For example, carbon dioxide from the atmosphere may be transferred to the water, or carbon dioxide generated or produced elsewhere may be introduced into the water.

<<Proton Removal Device 200>>
The proton removing device 200 removes protons (H ⁺ ) from water containing a marine product 100 that produces calcium carbonate (CaCO ₃ ) as part of itself.

The proton removal device 200 may be installed in an aquaculture facility 300 in which the marine product 100 is present (FIG. 1(a)), or may be connected to the aquaculture facility 300 (FIGS. 1(b) and (c)).

An aquaculture facility is a place in which marine products are cultivated. Examples of aquaculture facilities include, but are not limited to, tanks and aquaculture ponds installed on land, and underwater farms in rivers, lakes, and oceans. Such tanks, aquaculture ponds, and aquaculture farms may be newly installed or existing ones may be used. Note that aquaculture facilities are not limited to facilities for producing marine products for consumption, and include any facility, device, etc. that is intended to maintain, preserve, and grow marine products.

The proton removal device may be installed in any location where it can remove protons generated from marine products or protons generated by the acidification of seawater, etc. In other words, the proton removal device can be installed in any location where it can remove protons generated from marine products or protons generated by the acidification of seawater, etc. For example, it can be installed inside an aquaculture facility or in a location connected to an aquaculture facility. It may also be installed inside an existing aquaculture facility in freshwater, brackish water, or marine water (Figure 3 (b)), or in a location connected to an aquaculture facility (Figures 3 (a) and (c)). The proton removal device may be installed all the time, or may be installed to remove protons at a desired time.

When connecting the proton removal device to an aquaculture facility, proton-containing water can be flowed from the aquaculture facility into the proton removal device using a pipe or the like as shown in Figure 3(a), or equipment including the proton removal device can be installed directly near the aquaculture facility as shown in Figure 3(c), allowing proton-containing water from within the aquaculture facility to move to the equipment including the proton removal device.

When calcium ions (Ca ²⁺ ) and bicarbonate ions (HCO ₃ ^- ) are present in water, protons (H ⁺ ) are produced by the formation of calcium carbonate (CaCO ₃ ) (calcification reaction, → direction in formula (1) below).
Ca ²⁺ + HCO ₃ ^- ⇔CaCO ₃ + H ⁺ ...Formula (1)

When protons are removed by the proton removing device 200, the reaction proceeds in the → direction in formula (1), promoting the production of calcium carbonate (CaCO ₃ ).

Since the protons are removed, the reaction in the → direction in the following formula (2) is suppressed, and the release of carbon dioxide (CO ₂ ) into water is suppressed.
HCO ₃ ^- + H ⁺ ⇔H ₂ CO ₃ ⇔CO ₂ + H ₂ O...Formula (2)
As a result, carbon dioxide is fixed in the seafood.

It is also said that as seawater becomes more acidic, the production of calcium carbonate (← direction in the following formula (3)) is inhibited and its dissolution (→ direction in the following formula (3)) is promoted. However, by removing protons, acidification is suppressed and the production of calcium carbonate is promoted.
CaCO ₃ + CO ₂ + H ₂ O ⇔Ca ²⁺ +2HCO ₃ ^- …Formula (3)

Specific examples of proton removal devices that can be used include electron generators with an anode and a cathode, deionization devices, dialysis (dialysis devices), and distillation (distillation devices).

Furthermore, the proton removing device can be appropriately installed at a location where protons flow out by utilizing the current of water or the current of the tide. In this case, the installation location of the proton removing device can be changed depending on the current of water or the current of the tide.
The proton removal device may have a mechanism for controlling proton removal. This control mechanism makes it possible to adjust the on-off of the proton removal device and the amount of proton removal depending on the state of fixation of _CO2 in the marine products, the state of the algae, and/or the state of the water in the aquaculture facility.

<Electron Generator>
As the proton removing device 200, an electron generating device may be used as shown in FIG.

An electron generating device has at least an anode (also called a positive electrode or cathode) and a cathode (also called a negative electrode or anode), and the anode and cathode are connected to an external circuit, etc., so that electrons generated from the cathode can move to the anode. For example, the anode and cathode may be connected within a single device so that electrons can move, or the anode and cathode may be configured as separate devices, which are connected by an external circuit, etc., so that electrons generated from the cathode can move to the anode.

As an electron generating device, at least the anode needs to be in contact with water containing protons. If the electrons generated at the cathode can be transferred to the anode via an external circuit, etc., the cathode may or may not be in contact with water containing protons.

As shown in FIG. 2, a microbial battery may be used as an electron generator. When a microbial battery is used, a cathode (anode) can be inserted into a layer containing biomass (hereinafter, also referred to as bottom sludge or mud) or sludge (including activated sludge, the same below) such as mud accumulated at the bottom, or organic matter such as domestic wastewater, to form a microbial battery. Note that, as the place or layer in which the cathode is inserted, biomass or organic matter other than bottom sludge or sludge can be used as long as the power-generating bacteria can grow therein. The microbial battery in this embodiment is a device (microbial electron generator) that converts chemical energy of organic matter such as bottom sludge into electrical energy by utilizing the metabolic ability of microorganisms. The microbial battery uses electrons generated in the process of decomposing organic matter by microorganisms. The cathode (anode) collects electrons generated when microorganisms decompose organic matter, and the electrons move to the anode (cathode) through an external circuit. In this process, not only can electricity be generated using the power of microorganisms, but also organic matter contained in biomass such as bottom mud and domestic wastewater can be used as fuel, so microbial cells are attracting attention as a means of wastewater treatment and environmental purification while generating electricity (Patent Document 1). However, there have been no reports of using microbial cells to remove protons and promote calcium carbonate formation in marine products and carbon dioxide fixation in marine products.

In this embodiment, protons (hydrogen ions) released when marine products form calcium carbonate, protons generated by acidification of seawater, and oxygen in the water undergo a reduction reaction using electrons at the anode to generate water ( _H2O ). This reaction allows the protons in the water to be collected, promoting the fixation of carbon dioxide in the marine products.

In addition, during this process, the bottom mud, which is a reductant, changes into an oxidant, and the bottom mud is purified. This means that the mud at the bottom can also be purified. Furthermore, during this process, the organic matter in the bottom mud is decomposed by the power-generating bacteria, and nutrients such as nitrogen are dissolved into the water, which allows microalgae to grow. The proliferated microalgae can also purify the water.

<Deionization device>
A deionization device may be used as the proton removing device 200. In this case, for example, the proton removing devices shown in (a) to (c) of FIG.

A deionization device can be any device that can adsorb or remove protons. Examples include ion exchange devices and ion adsorption devices.

Examples of ion exchange devices include ion exchange membranes and ion exchange resins, and particularly preferred are cation exchange membranes and cation exchange resins.

The ion adsorption device may be any device capable of adsorbing or removing protons, such as zeolite, smectite (also called montmorillonite), charcoal, carbon nanotubes, metal complexes, etc., and may be a combination of these devices as long as they are capable of adsorbing or removing protons. Zeolite is preferred.

By using a deionization device, carbon dioxide fixation can be promoted using commercially available ion exchange devices, membranes, and resins. In addition, this configuration can be installed while utilizing existing equipment. This makes installation easy. Replacement is also easy because commercially available parts can be used.

<Dialysis equipment>
The proton removal device 200 may be a dialysis device.

The dialysis device can be any device capable of removing protons from the water surrounding the seafood. For example, a dialysis membrane can be used to remove protons from the water surrounding the seafood.

Electrodialysis can also be used. Electrodialysis is a technology that uses electrical force to separate and remove protons. For example, the device is made by stacking many pairs of alternating cation exchange membranes and anion exchange membranes with two types of spacers (demineralization compartment, concentration compartment) between them, and placing a pair of electrodes on both ends. When the raw liquid is supplied to the demineralization compartment, cations such as protons pass through the cation exchange membrane toward the cathode (negative electrode) and move to the concentration compartment on the right, but because the cathode side of the concentration compartment is separated by an anion exchange membrane, they cannot move further to the demineralization compartment on the right. As a result, cations such as protons are concentrated in the concentration compartment. Protons can be removed by removing this concentrated liquid.

By using a dialysis device, carbon dioxide fixation can be promoted using commercially available dialysis membranes. In addition, this configuration can be installed while using existing equipment as is, making installation easy. Replacement is also easy because commercially available parts can be used.

The device may be installed anywhere as long as it can remove protons generated from marine products and protons generated by the acidification of seawater, etc. For example, it may be installed inside or connected to an aquaculture facility. The dialysis device may be installed permanently, or may be installed to remove protons at the desired timing.

When connecting the dialysis device to the aquaculture facility, in the same way as the proton removal device, it is possible to use a pipe or the like as shown in Figure 3(a) to allow water containing protons to flow from the aquaculture facility into the proton removal device, or it is possible to install equipment including the dialysis device directly near the aquaculture facility as shown in Figure 3(c).

<Distillation Apparatus>
The proton removing device 200 may be a distillation device.

Distillation is a method of removing ions and impurities by boiling water to turn it into steam, then cooling it back into a liquid. Protons and hydrogen ions are also removed during this process. By using a device capable of performing distillation (hereafter referred to as a distillation device), this configuration can be installed while utilizing existing facilities as is, making installation easy. Distillation makes it possible to use sterilized water, making it hygienic and safe.

The device may be installed anywhere as long as it can remove protons generated from marine products and protons generated by the acidification of seawater, etc. For example, it may be installed inside or connected to an aquaculture facility. The dialysis device may be installed permanently, or may be installed to remove protons at the desired timing.

<<Aquaculture facility 300>>
The aquaculture facility 300 may be any place in which aquatic products exist in order to cultivate the aquatic products. For example, the aquaculture facility may be, but is not limited to, a water tank or aquaculture pond installed on land, or an aquaculture site in a river, lake, or seawater. Such a water tank, aquaculture pond, or aquaculture site may be newly installed or an existing one may be used. Note that the aquaculture facility is not limited to a facility for consuming aquatic products, and may include any facility, device, etc. that is intended to maintain, preserve, or grow aquatic products.

<<<<Carbon dioxide fixation method and program>>>
The carbon dioxide fixation method and carbon dioxide fixation program according to the first embodiment will be described with reference to FIG.

First, in step S101, a marine product that produces calcium as part of itself is placed in water.

Next, in step S102, protons are removed from the water.

The proton removal device may also act as a control server that removes protons from water.

The control server can be various types of personal computers or workstations equipped with a processor (such as a CPU (Central Processing Unit)), ROM (Read Only Memory), RAM (Random Access Memory), auxiliary storage devices (such as a HDD (Hard Disk Drive), SSD (Solid State Drive), or various memory cards), I/F (Communication Interface Device), input operation devices (such as a keyboard, mouse, or touch panel), and display devices (such as a liquid crystal display or touch panel). The control server can also perform various types of processing, such as various types of arithmetic processing and data processing, and communication processing with other servers.

The control server may be formed as a single device such as a personal computer as described above, or each function of the control server may be formed on a cloud that is accessible via the Internet.

The storage device accessible to the control server stores various programs (such as the carbon dioxide fixation program shown in Figure 4) and databases.

The storage device may be directly connected to the control server or may be located in the cloud via the internet.

<<<<Effects>>>
According to the carbon dioxide fixation system, carbon dioxide fixation method, and carbon dioxide fixation program of the first embodiment, it is possible to promote fixation of carbon dioxide in marine products during the biomineralization process in the production of calcium carbonate in marine products.

Specifically, by removing the protons that are generated during the production of calcium carbonate, it is possible to promote the fixation of carbon dioxide in seafood such as shellfish.

It can also promote calcium carbonate formation and growth in organisms such as coral reefs and shellfish, whose calcium carbonate formation is inhibited by ocean acidification.

Furthermore, it is preferable that the marine product 100 is a shellfish, crustacean, or cnidaria. This carbon dioxide fixation system can promote carbon dioxide fixation in the marine product that produces a shell or skeleton.

The proton removal device 200 may also be an electron generating device having an anode and a cathode. This carbon dioxide fixation system recovers protons in the water, promoting fixation of carbon dioxide in marine products. In this process, the bottom mud, which is a reductant, is converted into an oxidant, and the bottom mud is purified, so the bottom mud can also be purified. Furthermore, in this process, organic matter in the bottom mud is decomposed by the power-generating bacteria, and nutrients such as nitrogen are dissolved into the water, which allows microalgae to grow. The grown microalgae can also purify the water. This is because the microalgae absorb nutrients such as ammonia, nitrogen such as nitrate nitrogen or nitrite nitrogen, and phosphate in the water.

The proton removal device 200 may also be a deionization device. With this carbon dioxide fixation system, carbon dioxide fixation can be promoted using commercially available ion exchange devices, membranes, and resins. Furthermore, this configuration can be installed while utilizing existing equipment as is, making installation easy. Replacement is also easy because commercially available items can be used.

The proton removal device 200 may also be installed in the aquaculture facility 300 where the marine product 100 is present. With this carbon dioxide fixation system, the proton removal device 200 is installed in the existing equipment, so there is no need to secure a new installation site. Another advantage is that the proton removal device 200 can be installed closer to the marine product 100.

The proton removal device 200 may also be connected to the aquaculture facility 300 in which the marine products 100 are present. With this carbon dioxide fixation system, the proton removal device 200 can be installed as a retrofit without changing the configuration of the existing equipment. In this way, it is easy to introduce it into existing equipment.

<<<<Second embodiment>>>>
A second embodiment of the present invention will be described below with reference to the drawings. Fig. 5 is a block diagram showing a carbon dioxide fixation system 10 according to the second embodiment.

<<<Carbon Dioxide Fixation System 10>>>
As shown in FIG. 5 , the carbon dioxide fixation system 10 mainly comprises a proton removal device 200 that removes protons from water containing a marine product 100 that produces calcium carbonate as part of itself, and a water current generating device 500 that generates a water current toward the proton removal device 200.

The marine product 100, proton removal device 200, and aquaculture facility 300 are the same as those in the first embodiment.

<<Water flow generating device 500>>
The water flow generating device 500 generates a water flow toward the proton removing device 200 and/or toward the marine product 100 .

The water current generating device 500 generates the desired water current. Any device capable of generating a water current may be used, including a screw and a pump. Power sources that can be used include electricity, gas, wind power, tidal power, water currents, and solar power generation. These power sources can be used to rotate a screw or operate a pump to generate a water current. There are no particular limitations on the type of water current, but examples include a current from the deep layer to the surface, such as an upwelling current, a current in the opposite direction, and even a horizontal current.

The water flow generating device 500 may generate a water flow toward the proton removal device 200. This allows the protons to be removed efficiently.

The water flow generating device 500 may also generate a water flow toward the marine product 100. This allows the marine product to more efficiently fix the carbon dioxide absorbed by the algae. Furthermore, by making it easier for the marine product to ingest the algae that it feeds on, the growth of the marine product is promoted, and high-quality marine product can be cultivated. The direction of the water flow may be any one of the above or a combination of them.

The water flow generating device that generates a water flow toward the proton removal device 200 and the water flow generating device that generates a water flow toward the seafood 100 may be the same device or different devices.

<Algae>
Algae that serve as food for the marine product 100 may be present in the water in which the marine product 100 exists.
Algae will be described below.

Algae absorb carbon dioxide through photosynthesis, synthesize sugars, and release oxygen. They are classified according to culture conditions, species, culture water, and purification function. Algae are classified according to culture conditions, such as seawater-adapted species, freshwater-adapted species, brackish water-adapted species, species adapted to temperatures above 24 degrees, 21-24 degrees, 18-21 degrees, 15-18 degrees, 12-15 degrees, and 12 degrees or less. Algae are classified according to species, such as diatoms, blue-green algae, brown algae, green algae, euglena, dinoflagellates, and haptophytes (coccolithophorids, isochrysis, pavlova, etc.). Algae are classified according to culture water, such as acid-adapted species, neutral-adapted species, and alkaline-adapted species. Algae are classified according to purification function, such as heavy metal recovery and harmful substance recovery. These algae can be introduced into the aquaculture facility 300.

Algae that can be used as food for marine products and have a high ability to fix carbon dioxide can also be used. Specific examples include diatoms, blue-green algae, brown algae, green algae, euglena, dinoflagellates, and haptophytes (coccolithophorids, Isochrysis, Pavlova, etc.).

Different algae can be used depending on the season, culture conditions, and type of culture water used.

The water flow generating device 500 efficiently delivers algae as food to the marine product 100.

<<<<Carbon dioxide fixation method and program>>>
A carbon dioxide fixation method and a carbon dioxide fixation program according to the second embodiment will be described with reference to FIG.

First, in step S201, a marine product 100 that produces calcium as part of itself is placed in water.

Next, in step S202, a water flow is generated toward the proton removal device 200.

Next, in parallel with step S202, protons are removed from the water in step S203.

Furthermore, in parallel with steps S202 and S203, in step S204, a water flow is generated toward the seafood 100.

The order of steps S202 to 204 is not particularly limited. As long as protons can be removed and/or microalgae can be efficiently delivered to marine products as food, the order is not limited.

<<<<Effects>>>
According to the carbon dioxide fixation system, the carbon dioxide fixation method, and the carbon dioxide fixation program of the second embodiment, a desired water flow can be generated, thereby removing protons and allowing bait to reach the marine products more efficiently, thereby promoting carbon dioxide fixation in the marine products.

Specifically, the water flow generating device 500 generates a water flow toward the proton removal device 200, thereby enabling efficient removal of protons.

In addition, by generating a water flow toward the marine product 100 using the water flow generating device 500, the marine product 100 can efficiently ingest algae that exists in the same water and serve as food for the marine product 100, and the marine product can more efficiently fix the carbon dioxide absorbed by the algae. Furthermore, by making it easier for the marine product to ingest the algae that serves as food, the growth of the marine product is promoted, and high-quality marine product can be cultivated.

<<<<<Effect of proton removal device on microalgae proliferation>>>>
Fig. 7 shows a schematic diagram of the microalgae proliferation effect obtained by removing protons. In the example of Fig. 7, a microbial battery is used as an electron generating device, as in the example of Fig. 2, but various proton removing devices can be used as long as they can achieve the proliferation effect of microalgae.

In the example of FIG. 2, the bottom mud, which is a reductant, is converted into an oxidant, and the bottom mud is purified. In addition, in the example of FIG. 7, for example, it is possible to grow microalgae in an aquaculture facility or a symbiotic bioreactor by removing protons (FIG. 7). A symbiotic bioreactor is, for example, a device, facility, system, etc. that cultivates algae in a single aquaculture facility (such as aquaculture facility 300) and grows marine products that feed on the algae. A symbiotic bioreactor is disclosed in the specification of Japanese Patent Application No. 2023-122860 by the present applicant, etc.

Fig. 7 shows that in a configuration similar to that of the example of Fig. 2, in addition to purifying the bottom mud, the effect of growing microalgae can be obtained. As shown in Fig. 7, organic matter in the bottom mud is decomposed by the power-generating bacteria. Furthermore, nutrients such as nitrogen are dissolved in the water, and the nutrients cause the microalgae to grow. The growth of the microalgae then provides feed for marine products such as oysters.
Furthermore, the proliferation of microalgae allows water purification by the microalgae, since the microalgae absorb nutrients such as ammonia, nitrogen such as nitrate nitrogen or nitrite nitrogen, and phosphoric acid in the water.

In the example of FIG. 7, as shown on the left side of the figure, monitoring of the environmental modification dynamics is performed. Electrons generated by the electron generating device are detected by an ammeter 1202 included in the potential measuring unit. Furthermore, environmental power generation is performed in the environmental power generating unit 1204, and the environment is detected by various environmental sensors. The potential measuring unit is used for environmental monitoring, etc., and the measurement results of the potential measuring unit can be used to make decisions such as whether or not to further increase the number of proton removal devices.

According to the findings of the inventors, by thus growing microalgae using a proton removal device, it has become possible to fatten aquatic products in a shorter time. In other words, by using the symbiotic bioreactor disclosed in the above-mentioned Japanese Patent Application No. 2023-122860, it has become possible to fatten aquatic products such as oysters in a shorter time than before, but by further combining proton removal, it has become possible to fatten even shorter. In addition, by performing proton removal, it is possible to suppress the elution of carbon dioxide (CO ₂ ) from shells in aquatic products such as shellfish. As a result, as described above, the growth of the shell can be further promoted, and the size of the aquatic products can be increased.
Furthermore, the proton removal device can purify bottom mud, which makes it possible to improve the aquaculture environment. Also, the proton removal device can grow microalgae, which makes it possible to purify water and improve water quality. Furthermore, since microalgae can absorb nutrients such as ammonia, nitrogen such as nitrate nitrogen or nitrite nitrogen, and phosphate in the water, the proton removal device can grow microalgae, which makes it possible to purify the water.

<<<<<Various embodiments related to proton removal>>>>
<<<Other embodiment 1 relating to proton removal>>>
Regarding proton removal, various forms are possible in addition to the examples described above. For example, in the example of FIG. 8, the electron generator 1210 is formed in an inverted T-shape (with the horizontal part located at the bottom), and the anode (positive electrode) 1212 and the cathode (negative electrode) 1214 are integrally formed. The cathode 1214 side is buried in the bottom mud and extends, for example, horizontally in the bottom mud. The anode 1212 side protrudes into the water and extends, for example, directly upward. In other words, a microbial battery is formed using the electron generator 1210.

As shown on the right side of Figure 8, part of the carbon dioxide ( _CO2 ) dissolved in the ocean is fixed in the shells of marine products (bivalves in this case). During the biomineralization process in the production of calcium carbonate in marine products, protons are released and are absorbed and collected by the anode 1212. In this way, the protons released during shell formation are attracted to the anode side and combined with oxygen, thereby removing the released protons.

By forming the electron generating device 1210 in a T-shape as described above, the part on the side of the cathode 1214 is efficiently caught (engaged) in the bottom mud. This makes it possible to more reliably fix and position the electron generating device 1210 in the bottom mud. As a result, the installation of the electron generating device 1210 becomes easier. In addition, the electron generating device 1210 can be made in a simple shape, which makes it easier to mass-produce the electron generating device 1210. In addition, because the shape of the electron generating device 1210 is an inverted T-shape, the center of gravity is low and the posture of the conductive structure 1241 is easily stabilized.

The shape of the electron generator 1210 provided in the proton removal device may be any shape as long as the electric power generating bacteria can adhere to the negative electrode 1214 and the protons can be removed by the positive electrode 1212. A shape that stabilizes the proton removal device when installed is preferable. From another perspective, a shape that facilitates the attachment of the electric power generating bacteria and the removal of protons, or a shape that allows a large surface area for this purpose is preferable.

For example, the portion on the negative electrode 1214 side may be formed into a disk shape (or a rectangular disk shape or a polygonal disk shape, etc.), with a protruding portion for electron movement. Such a shape may be called, for example, a thumbtack shape. In this way, the disk-shaped portion on the negative electrode 1214 side can be hooked onto bottom mud. Furthermore, the negative electrode 1214 side may be a straight rod shape, and the positive electrode side may be disk-shaped, etc. In these cases, it is sufficient that at least a portion (including the cross section) of the shape of the electron generating device 1210 is T-shaped.

It is also possible to form the part on the negative electrode 1214 side radially, so that the negative electrode 1214 extends in multiple directions. In this case, for example, the electron generator 1210 can be shaped similarly to a tetrapod (wave dissipating block). In these cases, it is sufficient that at least a portion of the shape of the electron generator 1210 (including the cross section) is T-shaped.

In this way, more parts of the electron generator 1210 are fixed to the bottom mud. The electron generator 1210 can be more firmly fixed in the bottom mud. Furthermore, the surface area of the electron generator 1210 can be increased. In addition, by conforming to the shape of a commonly used object such as a tetrapod, a mold for a known object (such as a concrete mold) can be used, and since there is no need to create a new mold for molding, mass production at low cost is possible. In addition, as an example of the tetrapod shape is shown in FIG. 21 described later, the negative electrode 1214 extends in multiple directions (two or more directions), and the cross-sectional shape at multiple positions is T-shaped, so that at least a part of the shape (including the cross section) can be said to be T-shaped.

Figure 9 shows an example of the use of a proton removal device equipped with a tetrapod-type electron generator 1210. In the example of Figure 9, a large number of electron generators 1210 are installed in a matrix in the bottom mud of an aquaculture farm (aquaculture farm bottom mud). In the example of Figure 9, the negative electrode 1214 side protrudes outside the bottom mud. The negative electrode 1214 side may be entirely outside the bottom mud, or may be partially buried in the bottom mud. This is the same in the various embodiments described so far.

In the example of FIG. 9, the status of proton removal is monitored in real time. The monitoring is performed using a potential measurement unit 1216, and information on the potential detected by the potential measurement unit 1216 is wirelessly (or wired) communicated to a monitoring device 1218. "AVS" in FIG. 21 stands for "amount of acid-volatile sulfide." By providing such a potential measurement unit 1216 and monitoring the potential, environmental observation becomes possible. It is then possible to grasp the status of proton removal in water in real time.

<<<<Another embodiment 2 relating to proton removal>>>
Fig. 10 shows another embodiment of the proton removal. In the example of Fig. 10, the electron generator 1220 of the proton removal device is configured using a plurality (a large number) of steel slags 1228. The steel slags 1228 are by-products generated in the steel manufacturing process, and are spread on the bottom mud as shown from the upper left to the center of Fig. 10.

The steel slag 1228 is spread on the bottom mud and piled up in a state where it is in contact with other steel slag 1228. The underwater side of the piled steel slag 1228 becomes the positive electrode 1222, and the bottom mud side becomes the negative electrode 1224. In other words, a microbial battery is formed using the steel slag 1228.

In the example of Figure 10, as shown on the right side of the figure, carbon dioxide ( _CO2 ) in the atmosphere is taken up into the ocean and becomes marine dissolved _CO2 . Some of the marine dissolved _CO2 is fixed in the shells of marine products (bivalves in this case), for example, during shell formation.

In marine products, protons are released during the biomineralization process. The released protons are absorbed and collected by the steel slag 1228. In this way, the protons released during shell formation are attracted to the anode side and combined with oxygen, thereby removing the released protons.

The example in Fig. 10 provides a carbon dioxide fixation technology using steel slag 1228 and marine products (bivalves in this case). In this carbon dioxide fixation technology using steel slag 1228 and marine products (bivalves in this case), another part of the marine dissolved _CO2 is fixed in microalgae by photosynthesis, as shown in Fig. 11.

Here, the steel slag 1228 contains a large amount of iron, which is necessary for the growth of algae, phytoplankton, and the like. In general, steel slag is roughly divided into blast furnace slag, which is generated when iron ore is melted and reduced in a blast furnace, and steelmaking slag, which is generated in the steelmaking stage where iron is refined. Since steelmaking slag contains more iron, it is preferable to use steelmaking slag as the steel slag 1228 in the embodiment, or to contain as much steelmaking slag as possible.

<<Promotion of Microalgae Growth by Steel Slag 1228>>
Fig. 12 shows, step by step from left to right, the promotion of microalgae growth by steel slag 1228. First, in a bioreactor (bioreactor system) shown on the left side of Fig. 12, carbon dioxide ( _CO2 ) from the atmosphere is taken into the ocean and becomes marine dissolved _CO2 . Furthermore, the marine dissolved _CO2 is fixed by photosynthesis in microalgae, diatoms, photosynthetic bacteria, etc.

In the bioreactor, steel slag 1228 is spread on the bottom mud. The steel slag 1228 may be spread as in the example of FIG. 10. Iron (Fe), an element necessary for photosynthesis, and other substances are eluted from the steel slag 1228. Other substances include phosphorus (P), magnesium (Mg), calcium (Ca), and manganese (Mn). The iron elution effect of the steel slag 1228 lasts longer than inorganic iron salts. Then, photosynthesis is carried out using the iron from the steel slag 1228, resulting in the proliferation of microalgae.

Biomass such as microalgae grown in a bioreactor is introduced into a symbiotic bioreactor/carbon dioxide fixation system (hereinafter referred to as a "combined system") shown on the right side of Figure 12. In the combined system, the microalgae provide feed, and marine products such as shellfish are cultivated, promoting the fixation of _CO2 in the marine products. _CO2 is also fixed by photosynthesis in the microalgae.

In the combined system, protons are removed by the steel slag 1228, as in the examples of Figures 10 and 11. As a result, the growth of the marine products can be promoted, and the size of the marine products can be increased.

<<Example of carbon dioxide fixation system using steel slag 1228>>
Fig. 13 shows an example of a carbon dioxide fixation system using steel slag 1228 as a proton removal device. In the example of Fig. 13, a potential measurement unit 1236, an observation camera 1238, and an AI management system 1240 are added to the system similar to the example of Fig. 12.

The "microbial symbiotic bioreactor" in the upper left of Figure 13 corresponds to the "bioreactor" in the example of Figure 12. The "carbon dioxide fixation bioreactor" in Figure 13 corresponds to the "symbiotic bioreactor/carbon dioxide fixation system" (combined system) in the example of Figure 12.

The potential measurement unit 1236 may be the same as the potential measurement unit 1216 in the example of FIG. 9. The observation camera 1238 may be any camera capable of photographing marine products in water and transmitting the obtained image data (data of a direct observation image) to the AI management system 1240.

The AI management system 1240 is capable of managing the cultivation of marine products using AI (artificial intelligence). The AI management system 1240 mainly performs processes such as controlling the bioreactor, monitoring the microbial symbiotic flora, adjusting the biomass supply, monitoring the carbon dioxide fixation bioreactor, monitoring the bivalve growth effect, and acquiring electric potential data.

The AI management system 1240 handles physicochemical data, biological data, and bivalve cultivation status data. The physicochemical data includes various data such as temperature, pH, COD (chemical oxygen demand), BOD (biological oxygen demand), ammonia nitrogen, nitrate nitrogen, water-soluble phosphate, heavy metals, and potential data.

The biological data includes various data such as the type of microalgae, cell size, cell density, amount of chlorophyll a, and turbidity. The bivalve growth status data includes direct observation image data.

According to the example system of Figure 13, the carbon dioxide fixation system using steel slag 1228 can be made more automated.

<<<Other embodiment 3 relating to proton removal>>>
Fig. 14 shows yet another embodiment of proton removal. In this example, a steel slag 1228 is used in the electron generator of the proton removal device, and in this respect, the example of Fig. 14 is similar to the examples of Figs. 9 to 13. However, in the example of Fig. 14, the steel slag 1228 is mixed (embedded) in a conductive structure 1241 made of, for example, conductive concrete.

The conductive structure 1241 in the example of FIG. 14 is formed in a columnar shape (quadratic pyramid shape) with a trapezoidal cross section. The lower end of the conductive structure 1241 is buried in the bottom mud, and the upper end protrudes into the water. The lower end of the conductive structure 1241 becomes the negative electrode 1244, and the upper end becomes the positive electrode 1242. In other words, a microbial battery is formed using the conductive structure 1241.

According to the proton removal device of the example of FIG. 14, a large number of steel slags 1228 can be combined into one conductive structure 1241. This makes it easier to handle a large number of steel slags 1228. Furthermore, a longer (taller) electron generating device can be formed from a small amount of steel slag 1228. It is also possible to adjust the steel slag 1228 inside the conductive structure 1241 and mass-produce conductive structures 1241 with different characteristics. Furthermore, since the conductive structure 1241 has a trapezoidal shape, the center of gravity is low and the posture of the conductive structure 1241 is easily stabilized.

<<<Other embodiment 4 relating to proton removal>>>
Fig. 15 shows yet another embodiment of the proton removal. In the example of Fig. 15, an oyster (oyster) culture cage (hereinafter referred to as "culture cage") 1250 with a microbial battery system is suspended in water by a support wire 1251. The culture cage 1250 is a cage-like structure, inside which multiple aquatic products are cultured (here, single-seed oyster culture). The culture cage 1250 may be, for example, a farming cage.

A microbial battery (microbial battery system) is combined with the aquaculture cage 1250. The microbial battery system includes a positive electrode (anode) 1252 provided within the aquaculture cage 1250, and a negative electrode (cathode) 1254 installed in the bottom mud. The positive electrode 1252 is formed in an elongated shape and extends over almost the entire length of the interior of the aquaculture cage 1250. The mechanism of electron generation in the microbial battery system is similar to that of the various electron generating devices described above. The positive electrode 1252 may be divided into multiple parts as long as they can be used to form a microbial battery.

In the example of FIG. 15, carbon dioxide (CO ₂ ) in the atmosphere is taken into the ocean and becomes marine dissolved CO ₂ . Furthermore, a part of the marine dissolved CO ₂ is fixed in the shells of the marine products (here, oysters) in the aquaculture cage 1250. In the aquaculture cage 1250, protons are released during the biomineralization process in the production of calcium carbonate in the marine products. The released protons are absorbed and collected by the positive electrode 1252. In this way, the protons released during shell formation are attracted to the positive electrode 1252 side, and are removed by combining with oxygen, thereby suppressing the elution of CO ₂ from the shells.

Aquaculture cages 1250 like the example in Figure 15 can also be used in multiple rows, for example as shown in Figure 16. In this case, it is possible to scale up the proton removal system.

In the example of FIG. 16, a set of multiple aquaculture cages 1250 (four in this example) are arranged in a straight line in the water. Each aquaculture cage 1250 is combined with a negative electrode 1254 that constitutes a microbial battery. A positive electrode 1252 that constitutes a microbial battery is passed through each set of aquaculture cages 1250. The negative electrode 1254 is placed in the bottom mud and is electrically connected to the positive electrode 1252.

Inside each aquaculture cage 1250, proton removal is carried out in the same manner as in the example of FIG. 15. The status of proton removal is monitored in real time using a potential measuring unit 1216, etc.

This type of proton removal system makes it possible to remove protons on a large scale over a wide area. The arrangement of the aquaculture cages 1250 is not limited to the series arrangement shown in FIG. 16, but can be in various forms such as parallel, matrix, staggered, or combinations of these.

<<<Other embodiment 5 relating to proton removal>>>
Fig. 17 shows yet another embodiment of the proton removal. The example of Fig. 17 is similar to the example of Fig. 15 in that an oyster culture cage (hereinafter referred to as "culture cage") 1260 with a proton removal device (microbial battery system) is used. However, it differs from the example of Fig. 15 in that a negative electrode 1264 is installed inside the culture cage 1260.

In the example of FIG. 15, an environment in which the power-generating bacteria can grow is formed around the negative electrode 1264 inside the aquaculture cage 1260. In order to form an environment in which the power-generating bacteria can grow, it is possible to accommodate bottom mud at the bottom of the aquaculture cage 1260 and place the negative electrode 1264 in the bottom mud. In this way, it is possible to place the positive electrode 1262 and the negative electrode 1264 inside the aquaculture cage 1260. Then, it is possible to make the oyster aquaculture cage to which the microbial battery system is added compact in that the necessary components are integrated inside the aquaculture cage 1260. Note that biomass or organic matter other than bottom mud or sludge may be placed inside the aquaculture cage as long as it is capable of growing the power-generating bacteria.

<<<<Another embodiment 6 relating to proton removal>>>
Fig. 18(a) shows yet another embodiment of the proton removal. In the example of Fig. 18(a), a culture cage 1250 is used as in the examples of Fig. 15 and Fig. 16. A plurality of (four in this example) culture cages 1250 are suspended between supports 1274 via anode lines 1272. The supports 1274 are erected in the bottom mud and protrude into the water. The anode lines 1272 are stretched between the supports 1274.

Multiple (three in this example) negative electrode anchors 1276 are installed in the bottom mud, and the negative electrode anchors 1276 are electrically connected to the anode line 1272 via stainless steel wires 1278 and wire fixing hooks 1280. As shown in Figures 18(a) and 18(b), the negative electrode anchors 1276 have sharpened portions 1282 with sharp tips (lower ends in Figure 18(a)) and are stuck into the bottom mud. The anode line 1272 and the negative electrode anchors 1276 form a microbial battery system, and electrons move from the negative electrode anchors 1276 to the anode line 1272.

In the example of FIG. 18(a), the wire fixing hook 1280 is formed in a ring shape, and the anode line 1272 is passed inside the wire fixing hook 1280. The wire fixing hook 1280 can move along the anode line 1272, and the stainless steel wire 1278 and the negative electrode anchor 1276 can also move together with the wire fixing hook 1280.

Even with this embodiment, it is possible to remove protons in the same way as in the examples of Figures 15 and 16. It is then possible to remove protons on a large scale over a wide area. Note that the arrangement of the culture cages 1250 is not limited to the series arrangement shown in Figure 18(a), and various arrangements can be adopted, such as parallel, matrix, staggered, or combinations of these.

The negative electrode anchor 1276 is not limited to a configuration having multiple sharp tips 1282 as shown in FIG. 18(b), but may have a configuration having one sharp tip 1284, such as the negative electrode anchor 1286 shown in FIG. 18(c). In the example of FIG. 18(c), the sharp tip 1284 is formed in a cone shape.

The sharpened portion 1282 shown in FIG. 18(b) and the sharpened portion 1284 shown in FIG. 18(c) may be, for example, a conductive structure formed from conductive concrete. Furthermore, the negative electrode anchors 1276, 1286 may be entirely formed from conductive concrete. By doing so, it becomes possible to easily mass-produce the sharpened portions 1282, 1284 and the negative electrode anchors 1276, 1286.

<<<Other embodiment 7 relating to proton removal>>>
FIG. 19 shows yet another embodiment of the proton removal. In this embodiment, the proton removal device 200 is submerged in water such as seawater. The proton removal device 200 does not have to be completely submerged in water, and the proton removal device 200 may be installed at any location where water containing protons flows into the proton removal device 200. For example, the proton removal device 200 may float in water, or a part of the proton removal device 200 may be submerged in water. In the proton removal device 200 of this embodiment, bismuth oxide chloride (BiOCl) is used as the positive electrode (anode), and metals such as Ag, Cu, Au, and Pt are used as the negative electrode (cathode). In addition, materials other than metals can be used as the positive electrode (anode) as long as they have the same function. When water containing protons is supplied to the proton removal device 200 and the water is introduced between the positive electrode (anode) and the negative electrode (cathode), protons are removed from the water.
Specifically, protons are removed at the positive electrode (anode) as the following reaction takes place:
BiOCl+2H ⁺ +3e ^- →Bi+Cl ^- +H ₂ O
Electrons move from the positive electrode (anode) to the negative electrode (cathode), and negative ions (Cl- ^ions ) in the water are induced to the negative electrode (cathode), where the following reaction occurs:
3×(X+Cl ⁻ →XCl+e ⁻ ) X: Ag, etc. By this mechanism, protons in water are removed.
According to this embodiment, even when no organic matter such as bottom mud is present, the effect of being able to remove protons can be obtained in the same way as in the embodiments 1 to 6. The proton removal device 200 may be installed anywhere as long as the water from which protons are to be removed can be introduced into the proton removal device 200.

<<<<Another embodiment 8 relating to proton removal>>>
20 shows yet another embodiment relating to proton removal. In this embodiment, a proton removal device 200 having a configuration similar to that of the seventh embodiment is installed outside a water system such as seawater containing protons. The mechanism for removing protons is the same as that of the seventh embodiment.
In this embodiment, water containing protons is passed through a water supply path 3000 by a pump (not shown) or gravity, and is supplied to the proton removal device 200. The water from which protons have been removed in the proton supply device 200 passes through a water discharge path 3010 and is returned to water such as seawater.
According to this embodiment, the same effects as those of the seventh embodiment can be obtained. Furthermore, the proton removing device 200 can be installed outside the water from which protons are to be removed. This provides the effect of facilitating maintenance of the proton removing device 200.

Each embodiment of the carbon dioxide fixation system, carbon dioxide fixation method, and carbon dioxide fixation program described so far can also be applied to an environmental purification system, an environmental purification method, and an environmental purification program, respectively. Note that environmental purification refers to removing, reducing, removing, fixing, etc., pollutants from polluted air, water, soil, etc., and includes, but is not limited to, removing or fixing carbon dioxide on the earth, purifying mud that has accumulated at the bottom, purifying water, etc.

<<<<<Scope of the embodiment>>>>
As described above, the present embodiment has been described. However, the description and drawings forming a part of this disclosure should not be understood as being limiting. Various embodiments not described here are included.

10 Carbon dioxide fixation system 100 Aquatic product 200 Proton removal device 300 Aquaculture facility 400 Equipment including proton removal device 500 Water flow generator 1210 Electron generator 1220 Electron generator 1228 Steel slag 1241 Conductive structure 1250 Aquaculture cage 1260 Aquaculture cage 1272 Anode line 1276 Negative anchor

Claims (14)

a proton removing device for removing protons from water in which a marine product that produces calcium carbonate as a part of itself is present;
and a potential measuring unit that monitors the state of the removal of protons ;
the proton removing device is an electron generating device having an anode and a cathode,
A carbon dioxide fixation system , wherein the marine product is a shellfish, a crustacean, an echinoderm, a cnidaria, or an algae that produces calcium carbonate as part of itself by utilizing a calcification reaction that produces calcium carbonate from carbon dioxide and calcium . The carbon dioxide fixation system according to claim 1 , further comprising a mechanism for controlling the removal of the protons. The carbon dioxide fixation system according to claim 1 or 2, wherein the proton removal device removes protons directly or indirectly from water in which the marine product is present. 2. The carbon dioxide fixation system of claim 1, wherein in the electron generating device, the anode comprises bismuth oxide chloride (BiOCl) and the cathode comprises a metal selected from Ag, Cu, Au, and Pt. The carbon dioxide fixation system according to claim 1 , wherein in the electron generating device, the cathode is installed in a layer containing biomass or organic matter containing electricity-generating bacteria. The carbon dioxide fixation system according to claim 1, characterized in that the proton removal device is installed in an aquaculture facility in which the marine products are present. The carbon dioxide fixation system according to claim 1, characterized in that the proton removal device is connected to an aquaculture facility where the marine products are present. The carbon dioxide fixation system of claim 1, further comprising a first water flow generating device that generates a water flow toward the proton removal device. The carbon dioxide fixation system according to claim 8 , further comprising a second water flow generating device that generates a water flow toward the seafood. The carbon dioxide fixation system according to claim 1, characterized in that at least a portion of the proton removal device is T-shaped. The carbon dioxide fixation system according to claim 1, characterized in that the removal of protons is carried out using steel slag. 2. The carbon dioxide fixation system according to claim 1, wherein the removal of protons is performed using an aquaculture cage. A step of placing a seafood product that produces calcium carbonate as a part of itself in water;
removing protons from the water using a proton removal device ;
and monitoring the status of the removal of protons.
The method for fixing carbon dioxide, wherein the marine product is a shellfish, a crustacean, an echinoderm, a cnidaria, or an algae that produces part of itself as calcium carbonate by utilizing a calcification reaction that produces calcium carbonate from carbon dioxide and calcium . The carbon dioxide fixation method according to claim 13, further comprising a step of controlling the removal of the protons.