JP2577709B2 - Concrete structure with slow release of iron ions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a good growth of fish and shellfish by slowly releasing iron ions, thereby allowing aquatic plants such as seaweeds and diatoms to grow, survive and proliferate in a short period of time. The present invention relates to a concrete structure for constructing a seaweed bed.

[0002]

2. Description of the Related Art In recent years, there has been an increasing interest in improving the environment of the aquatic environment, and methods and techniques for maintaining a good ecological balance of aquatic plants and animals have been developed. The sea area where the reefs are submerged and the water area where the wave-dissipating blocks are installed are used as a seaweed bed where aquatic plants such as seaweeds prosper, and a method of making living places where fish and other aquatic animals can easily live is being implemented. A method to promote the growth of seaweeds, etc. by applying paint containing iron compounds such as iron sulfate on the surface of fishing reefs and wave breaking blocks to create good seaweed beds and supplying iron, a trace element of aquatic plants Has been taken.

Further, a technique has been developed in which iron is mixed with a concrete block to promote the growth environment of seaweed. For example, Japanese Unexamined Patent Publication (Kokai) No. 5-192048 discloses a concrete block for seaweed cultivation in which an iron material is mixed with cement and molded. Also, Japanese Patent Application Laid-Open No. 5-268854 describes a technique for efficiently propagating seaweed by attaching iron-containing waste to the surface of a concrete block.
Furthermore, Japanese Patent Application Laid-Open No. 6-9453 describes a fishing reef that uses a metal surface to improve the adhesion of seaweed as compared with a concrete block.

[0004]

As described above, a fishing reef or a wave-dissipating block coated with an iron compound, a fishing reef containing iron, or a fishing reef having iron on the surface has a high speed at which excess iron is removed from the surface. And a sufficient amount of nutrients is supplied in a small amount to aquatic plants, and the growth of seaweed often deteriorates. Excessive release of iron compounds
It can also cause water pollution. Further, in order to manufacture this type of fishing reef or wave-dissipating block, a process of forming a material such as concrete and then applying a paint is required, which complicates the process and increases the manufacturing cost. The development of technologies and methods for manufacturing a seaweed bed reef and a water-dissipating block with abundant aquatic vegetation that has a simple manufacturing process and does not cause water pollution are awaited.

The present invention has been developed with the aim of realizing this. An important object of the present invention is to gradually release iron ions as a trace element, thereby enabling aquatic plants such as seaweeds and diatoms to be released. It is an object of the present invention to provide an iron ion sustained-release concrete structure capable of supplying iron necessary for the growth of the iron and preventing the excessive elution of iron. Another important object of the present invention is to provide a concrete structure having a slow release of iron ions, which can be easily and efficiently produced at a low cost.

[0006]

SUMMARY OF THE INVENTION The concrete structure of the present invention has an iron structure in which iron ions or a chelate compound of iron ions are supported on concrete in order to suppress and control the release of iron to an optimum amount for the growth of aquatic plants. Adsorption carrier is mixed. The concrete structure of the present invention does not simply contain iron physically in concrete. Iron is chemically bonded and supported on an adsorption carrier such as zeolite in a state of being ionically bonded.

[0007] The iron-adsorbing carrier for supporting iron may be any of zeolite such as artificial zeolite, synthetic zeolite and natural zeolite, diatomaceous earth, activated carbon, silica, bentonite, kaolinite, cation exchange resin, corrosive acid and peat. What carried iron on the carrier can be used. The adsorption carrier carrying iron has, for example, a cation exchange capacity of 50 to 600 meq per 100 g, preferably 80 meq.
q to 600 meq or more, more preferably 100 meq
~ 600meq, optimally 200meq ~ 600meq
Is used. Since the adsorption carrier having a large cation exchange capacity can adsorb more iron, the mixing amount of the iron adsorption carrier can be reduced, and an excellent effect can be obtained.

In order to carry iron on an adsorption carrier having excellent cation adsorption ability, the adsorption carrier is immersed in an aqueous solution containing iron ions. The immersion time is, for example, several hours or more. In the adsorption carrier immersed in the aqueous solution containing iron ions, positive ions are bound to the negatively charged portions. As the aqueous solution containing iron ions, for example, aqueous solutions of iron chloride, iron sulfate, and iron nitrate can be used.

Further, the adsorption carrier can carry a chelate compound of iron ions. This iron adsorption carrier,
The adsorption carrier is immersed in an aqueous solution containing a chelate compound of iron ions. In the aqueous solution containing the chelate compound of iron ions,
For example, an aqueous solution of iron citrate can be used.

[0010] The concrete structure of the present invention can be manufactured by mixing an iron-adsorbing carrier into a ready-mixed concrete in which aggregate and cement are kneaded, and forming a ready-mixed concrete mixed with the iron-adsorbing carrier in a mold.

[0011] The amount of the iron-adsorbed carrier mixed varies depending on the cation exchange capacity of the iron-adsorbed carrier. 2 cation exchange capacity
This is because the iron adsorption carrier which is twice as large contains half the same amount of iron. When an iron adsorbent having a cation exchange capacity of 200 meq / 100 g is used, the amount of the iron adsorbent added is, for example, 3 to 50 parts by weight, preferably 3 to 40 parts by weight, based on 100 parts by weight of cement added to concrete. Parts by weight, more preferably 4 to 30 parts by weight, optimally 10 to 10 parts by weight.
Set to 20 parts by weight. When the cation exchange capacity of the adsorption carrier is doubled, the addition amount of the iron adsorption carrier is halved, and when the cation exchange capacity is halved, the addition amount of the iron adsorption carrier is doubled. Therefore, the optimal amount of the iron adsorbent increases or decreases in inverse proportion to the cation exchange capacity.

[0012] If the mixing amount of the iron-adsorbing carrier is too large or too small, the environment is not optimal for the growth of aquatic plants. If it is too low, it will not be possible to supply the optimal amount of iron for the growth of aquatic plants. On the other hand, if the mixing amount is too large, excess iron is replenished, and the environment is not optimal for the growth of aquatic plants.

[0013]

[Function] A concrete structure mixed with an iron-adsorbing carrier carrying iron ions is used to remove iron from the iron-adsorbing carrier over time.
Releases very slowly over long periods. Preferably, when the nutrient adsorption site of aquatic plants such as seaweeds and diatoms comes into contact with the iron ions carried by the iron adsorption carrier, the ions are exchanged with the hydrogen ions secreted from this portion and are efficiently released, and the aquatic plants are released. Supplies to plants. Since iron adsorption carriers do not almost release iron ions unless iron is absorbed by plants,
Excess iron is released into seawater, and iron does not pollute the water quality. Since the iron contained in the iron-adsorbing carrier is efficiently replenished to the roots of the aquatic plant, it can be efficiently replenished to the aquatic plant for an extremely long period of time, and the aquatic plant can prosper effectively. Unlike conventional fishing reefs coated with iron sulfate, iron does not dissolve in seawater and elute in a short period of time.

[0014]

Next, examples of the present invention will be described. Manufacture concrete structures such as fishing reefs and wave-dissipating blocks as follows.

Process for Producing an Adsorbent Support As described below, fly ash, which is a large amount of coal ash generated at power plants and the like, is used as an adsorbent support having excellent cation adsorption power. Manufacture artificial zeolite. To make fly ash an artificial zeolite,
The fly ash is immersed in a 1N aqueous solution of sodium hydroxide for several hours and stirred. However, the concentration of the aqueous caustic soda solution is 1
N to 3N. Then, it is washed with water and dried to obtain a powdery artificial zeolite. The fly ash immersed in the aqueous solution of caustic soda combines Si and Al via O to form an artificial zeolite of Na type. In the artificial zeolite thus manufactured, four Os are bonded to Si and Al. Since Si has a positive tetravalent value and Al has a positive trivalent value, one extra electron in the Al portion serves as an adsorption carrier that is charged negatively. In the artificial zeolite of the Na type, iron ions, which are positive ions, are bonded to the negatively charged portions of Al. The artificial zeolite thus produced has a cation exchange capacity of about 200 meq / 100 g.

Step of Adsorbing Iron Ions on Artificial Zeolite as Adsorption Carrier Artificial zeolite as an adsorption carrier obtained from fly ash is immersed in an aqueous solution containing iron ions to adsorb iron ions on the artificial zeolite. In aqueous solutions containing iron ions,
An aqueous solution of iron chloride having a concentration of 1N is used. The immersion time of the artificial zeolite, which is the adsorption carrier, is 3 hours. When the adsorption carrier is immersed in an aqueous solution of iron chloride, iron ions are bonded to the negatively charged portion, resulting in an iron-type artificial zeolite as an iron adsorption carrier. After adsorbing iron ions to make an iron-adsorbing carrier, it is washed with water and dried to obtain a powdery iron-adsorbing carrier.

Step of Manufacturing Concrete Structure Using Iron-Adsorbing Carrier An iron-type artificial zeolite, which is an iron-adsorbing carrier, is mixed with cement. The mixing amount of the iron-type artificial zeolite is five stages of 10, 20, 30, 40, and 50% with respect to the cement to be mixed. That is, iron adsorbent, 10 parts by weight, 20 parts by weight, 30 parts by weight with respect to 100 parts by weight of cement,
40 parts by weight and 50 parts by weight are mixed. The iron-type artificial zeolite and cement are mixed with the aggregate, water is further added thereto, and the mixture is kneaded to obtain ready-mixed concrete. Sand and gravel are used for aggregate. The mixing ratio of cement, sand, gravel and water is
With respect to 100 parts by weight of cement, 150 parts by weight of sand, 300 parts by weight of gravel, and 50 parts by weight of water are used.

[0018] Using a ready-mixed concrete in which iron-type artificial zeolite is mixed with this cement, the height is 25 cm and the width is 40 c.
m, rectangular block with a height of 5 cm (projected plane area:
0.1 square meter, volume: 0.005 cubic meter,
(Weight: 11.5 kg) to form an example block of the present invention.

A rectangular parallelepiped block was prepared in the same manner as described above, except that iron-type artificial zeolite, which is an iron-adsorbing carrier, was not mixed with the iron, and a block of Comparative Example 1 was prepared. Further, a rectangular parallelepiped block was produced in the same manner as described above, except that a coating containing iron sulfate was applied to the surface without mixing the iron-adsorbing carrier, thereby producing a comparative example 2 block. Example blocks and Comparative Examples 1 and 2 were submerged in the sea at an average water depth of about 2 m on the coast of Matsushige-cho, Tokushima Prefecture, and the state of implantation and growth of seaweed was observed. Furthermore, the Example block and the Comparative Examples 1 and 2 blocks produced in the same manner were immersed in the Yoshino River at a depth of 2 meters in Anabuki-cho, Tokushima Prefecture, and the state of implantation growth of diatoms was observed.

One week after submerging in the sea, the formation of seaweed (red algae) was observed in the example block. There was no change between the comparative example block and the conventional example block, and no seaweed formation was observed. Two weeks later, seaweeds (green algae) had formed on the example blocks, but in Comparative Examples 1 and 2, there was no change and no seaweeds (green algae) were formed. When four weeks had elapsed, the green algae had grown to cover more than half of the surface of the example block. On the other hand, in Comparative Examples 1 and 2, the formation of seaweed was still not recognized.

After three weeks, diatoms settled on the Example block and the Comparative Example 2 block, and no diatom formed on the Comparative Example 1 block. Three months after sinking in the river, the diatoms flourished to cover almost the entire surface of the example block. The diatoms that had settled disappeared after three months in the Comparative Example 2 block where diatoms had settled after three weeks. Comparative Example 1 block
Diatoms did not grow even after 3 months.

FIG. 1 shows a state in which an example block manufactured by adding 20 parts by weight of artificial zeolite to cement is immersed in the sea for 4 weeks. Example block 1 which is a concrete structure of the present invention shown in FIG.
Means that seaweed 2 (mostly green algae) is active over almost two-thirds of the block surface, and about 5 cm in height for large ones
It grows to reach even more. In the vicinity of the seaweed 2, a snail 3 also lives, forming one small ecosystem. On the other hand, seaweed formation was hardly observed in the conventional comparative example block to which the iron adsorption carrier was not added.

FIG. 2 shows a state in which three months have passed since the embodiment block manufactured by adding 20 parts by weight of artificial zeolite to cement was submerged in a river. Example block 1 which is a concrete structure of the present invention shown in FIG.
The diatom 4 was activated over almost the entire surface of the block.

From the above results, it was clarified that the example block to which the iron-type artificial zeolite was added exhibited the effects of attraction, epiphytic growth and vigorous growth of aquatic plants such as seaweeds and diatoms. Excessive mixing of artificial zeolite may reduce the effect of aquatic plants to settle. Therefore, the most effective effect is obtained when the amount of the iron adsorbent added is about 20% with respect to 100 parts by weight of cement. With such a degree of mixing, the strength of the block hardly decreases, and the block can sufficiently withstand destruction.

The amounts of iron-type artificial zeolite mixed and the degree of epiphyte of aquatic plants such as seaweeds and diatoms in the example blocks were as follows. In the example block of the present invention, the largest amount of aquatic plants flourished when 20 parts by weight of the iron-type artificial zeolite was added to 100 parts by weight of cement. With the addition of 10 parts by weight of the iron-type artificial zeolite, the example block slightly reduced the aquatic plant growth. When the addition amount of the iron-type artificial zeolite was more than 20 parts by weight, the amount of aquatic plants that flourished gradually decreased. Therefore, the cation exchange capacity is 200 meq / 1
The optimal mixing amount of the iron-type artificial zeolite in which iron ions are bonded to the artificial zeolite of 00 g is 10 to 20 parts by weight based on 100 parts by weight of cement.

As the iron-adsorbing carrier, a carrier carrying a chelate compound of iron ion instead of iron ion can be used. The iron adsorption carrier supporting the chelate compound of iron ions is manufactured as follows. The artificial zeolite is immersed in an aqueous solution containing a chelate compound of iron ions to adsorb the chelate compound of iron ions on the artificial zeolite. As the aqueous solution containing the iron ion chelate compound, an aqueous solution of iron citrate having a concentration of 1N is used. The immersion time of the artificial zeolite, which is the adsorption carrier, is 3 hours. When the adsorption carrier is immersed in an aqueous solution of iron citrate, a chelate compound of iron ions is bonded to the adsorption site, and an artificial zeolite as an iron adsorption carrier is obtained. After adsorbing a chelate compound of iron ions to obtain an iron-adsorbing carrier, it is washed with water and dried to obtain a powdery iron-adsorbing carrier.

An example block was experimentally produced in the same manner as described above, except that the iron adsorption carrier supporting the iron ion chelate compound produced as described above was used. In this embodiment block, the same prosperous effect as the above-mentioned embodiment block using the iron adsorption carrier supporting iron ions is obtained by using the same amount of the iron adsorption carrier.

Example blocks were experimentally produced in the same manner as described above, except that the adsorption carrier was a natural zeolite having a cation exchange capacity of 100 meq / 100 g from an artificial zeolite. This example block uses a natural zeolite, whose cation exchange capacity is half that of an artificial zeolite, as an adsorption carrier. In this example block, when the addition amount of the iron adsorption carrier is doubled, the same aquatic plant growth effect can be obtained as compared with the example block in which artificial zeolite is used as the iron adsorption carrier.

Further, an example block was experimentally produced in the same manner as described above, except that a synthetic zeolite having a cation exchange capacity of 500 meq / 100 g was used instead of the artificial zeolite. This example block uses a synthetic zeolite having a cation exchange capacity 2.5 times that of an artificial zeolite as an adsorption carrier. In this example block, the amount of the iron adsorption carrier added was reduced to 1 / 2.5 compared to the example block using artificial zeolite as the iron adsorption carrier.
An equivalent aquatic plant growth effect is obtained.

Further, the concrete structure of the present invention comprises:
100% instead of zeolite
The cation exchange capacity per g is 50meq-600me
q, preferably 80 meq to 600 meq or more, more preferably 100 meq to 600 meq, and most preferably 20 meq to 600 meq.
0 to 600 meq, diatomaceous earth, activated carbon, silica, bentonite, kaolinite, cation exchange resin,
What carried iron on the adsorption carrier, such as corrosive acid and peat, can also be used. As the adsorption carrier to be added as an iron adsorption carrier to the concrete structure of the present invention, those having a cation exchange capacity per 100 g, preferably within the following range, can be used. Artificial zeolite 150-400 meq Natural zeolite 50-200 meq Synthetic zeolite 350-600 meq Bentonite 100-120 meq Cation exchange resin 200 ~ 1000meq Corrosive acid ... 300 ~ 800meq Peat ... 200 ~ 300meq

These adsorption carriers can be immersed in an aqueous solution containing iron ions or iron chelate compounds to form iron adsorption carriers that carry iron ions or iron ion chelate compounds. The amount of the iron adsorption carrier using a large cation exchange capacity as the adsorption carrier is reduced, and the amount of the iron adsorption carrier of the adsorption carrier having a small cation exchange capacity is increased.

An adsorbent having a large cation exchange capacity generally has a high cost. The artificial zeolite produced using fly ash as a raw material is ideal as an adsorption carrier to be added to the concrete structure of the present invention. This is because enormous waste generated in power plants and the like using coal as fuel can be effectively used, and aquatic plants can prosper effectively due to excellent cation adsorption capacity.

[0033]

Industrial Applicability The iron ion sustained release concrete structure according to the present invention can supply a minimum amount of iron as a trace element and improve the aquatic plant settlement. Fish reefs, wave-dissipating blocks and seawalls, which are overgrown with aquatic plants, provide an environment where various types of fish can easily survive, and thus have the effect of keeping the aquatic ecosystem favorable. The production of concrete structures such as fishing reefs, wave-dissipating blocks, seawalls and the like is economically and economically inexpensive because the conventional process of applying a paint containing iron is unnecessary. In addition, since an excessive elution of iron does not occur, an environment-friendly fishing reef or a concrete structure such as a wave-dissipating block or a seawall block which does not pollute the hydrosphere may be a great effect.

[Brief description of the drawings]

FIG. 1 is a plan view showing a seaweed formation state of an example block.

FIG. 2 is a plan view showing a diatom epiphytic state of an example block.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Example block 2 ... Seaweed 3 ... Conch 4 ... Diatom

 ────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-284836 (JP, A)

Claims (2)

(57) [Claims] 1. A concrete structure having a slow release of iron ions formed by concrete mixed with an iron adsorption carrier supporting iron ions or a chelate compound of iron ions. 2. The iron-adsorbing carrier according to claim 1, wherein the iron-adsorbing carrier comprises zeolite, diatomaceous earth, activated carbon, silica, bentonite, kaolinite, a cation-exchange resin, a corrosive acid, or peat, and iron is supported thereon. 2. The concrete structure with slow release of iron ions according to 1.