JP7302864B2 - CLEANING COMPOSITIONS AND METHODS OF USING CLEANING COMPOSITIONS - Google Patents

Description

The present invention relates to cleaning compositions and methods of using the cleaning compositions.

After the edible portion is removed from the shellfish, the shells are disposed of as industrial waste, and the amount is said to amount to more than several hundred thousand tons per year. The present inventor has continued various studies based on the idea that shells, which are to be discarded, should be effectively used as resources. Focusing on the sterilization and antibacterial action, a device for spraying such a solution and a device capable of preparing a large amount of such a solution have been proposed (see Patent Documents 1 to 3).

By spraying the solution containing the components eluted from the baked shell powder, the environment can be sterilized and the growth of bacteria can be suppressed. Moreover, by preparing a large amount of the solution containing the components eluted from the baked shell powder, it can be used as a liquid for washing a large amount of vegetables, tableware, and the like.

Since then, the present inventor has continued to search for applications in which seashells can be effectively used as a resource, and in the process, has developed a new cleaning composition.

Utility Model Registration No. 3172527 Utility Model Registration No. 3199107 Utility Model Registration No. 3199108

As described above, an object of the present invention is to provide a new cleaning composition that can effectively utilize seashells as a resource, and a method for using the cleaning composition.

In order to solve the above problems, the cleaning composition according to the present invention is
"Baked shell powder with an average particle size of 5 μm to 10 μm,
malfan stone powder and
a surfactant;
citric acid;
sodium salt and”.

The type of shellfish used as the "baked shell powder" is not particularly limited, and scallops, oysters, surf clams, clams, short-necked clams, etc. can be used. In Japan, it is said that scallop shells account for more than 60% of all the shells that are discarded as industrial waste. . The temperature at which the shell is "baked" can be between 1000°C and 1200°C. When the crystal phase of the shell is identified by X-ray diffraction, the main component of the unfired shell is calcium carbonate. Almost becomes a single phase of calcium oxide.

The "average particle size" of the calcined shell powder is the volume-based median size in the particle size distribution determined by the laser diffraction/scattering method.

"Maifanseki" belongs to quartz porphyry or granite porphyry, and is a mineral composed mainly of alkali feldspar and quartz. The chemical composition contains 65% to 70% by mass of silicic anhydride, 12% to 16% by mass of aluminum oxide, and 2% to 4% by mass of potassium oxide, sodium oxide, calcium oxide, and magnesium oxide, respectively. %.

The cleaning composition of this configuration can be used for cleaning various objects to be treated, as will be described later in detail. This cleaning composition was invented mainly by paying attention to the ion-exchange ability of maifanseki, and is therefore suitable for applications in which the ion-exchange ability can be sufficiently exhibited.

The method of using the cleaning composition according to the present invention (hereinafter sometimes simply referred to as "method of use") is as follows:
"To the water to which the cleaning composition described above has been added,
The solid object to be treated is immersed, or the solid object to be treated is stirred while being immersed.

If only a solution is used as in the techniques of Patent Documents 1 to 3, the ion exchange capacity of maifanseki in the cleaning composition cannot be effectively exhibited. Therefore, the cleaning composition having the above structure is used by immersing a solid object to be treated in water to which it is added. If necessary, the solid object to be treated is stirred while being immersed.

The method of using the cleaning composition according to the present invention includes, in addition to the above configuration,
"The object to be treated is at least one of soil contaminated with radioactive cesium and soil contaminated with heavy metals."

Any of the cases where the material to be treated is soil contaminated with radioactive cesium, soil contaminated with heavy metals, or soil contaminated with both radioactive cesium and heavy metals, the above uses By applying the method, the concentration of contaminants in the object to be treated can be effectively reduced, as will be described later in detail.

The method of using the cleaning composition according to the present invention, instead of the above configuration,
"The cleaning composition described above is added to a liquid object to be treated and stirred,
The object to be treated is at least one of water contaminated with radioactive cesium and water contaminated with heavy metals."

The above use, regardless of whether the material to be treated is water contaminated with radioactive cesium, water contaminated with heavy metals, or water contaminated with both radioactive cesium and heavy metals. By applying the method, the concentration of contaminants in the object to be treated can be effectively reduced, as will be described later in detail.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to provide a novel cleaning composition that can effectively utilize seashells as a resource, and a method for using the cleaning composition.

Hereinafter, a cleaning composition that is one embodiment of the present invention and a method for using this cleaning composition will be specifically described.

First, the composition of the cleaning composition will be described. The cleaning composition of the present embodiment contains calcined shell powder, malfanseki powder, surfactant, citric acid, and sodium salt.

The calcined shell powder is powder obtained by calcining scallop shells at a temperature of 1130° C. and pulverizing the scallop shells. When the particle size of the calcined shell powder was measured using a laser diffraction/scattering particle size distribution measuring device Microtrac MT3000II manufactured by Microtrac Bell, the volume-based median diameter was 6 μm to 9 μm. The cleaning composition of the present embodiment contains 3.0% by mass to 10.0% by mass of such calcined shell powder.

As the maifan stone, No. 1 was used among powders obtained by pulverizing Nobi rhyolite (Shirakawa stone) collected in the Shirakawa district of Gifu prefecture. 400 mesh and no. A fine powder with a particle size of 37 μm to 44 μm that does not pass through a 325 mesh was used. The cleaning composition of the present embodiment contains 0.5% by mass to 5.0% by mass of such maifanseki powder.

An alkyl ether type nonionic surfactant was used as the surfactant. Since nonionic surfactants have low foaming properties, there is an advantage that the rinsing process can be completed early when the rinsing process is performed after the washing process. In addition, nonionic surfactants have the advantage of being able to use well water or the like as the "water" used as the water medium for purification, since the action as a surfactant is less likely to be affected by the hardness of water. The cleaning composition of the present embodiment contains 5.0% by mass to 10.0% by mass of the nonionic surfactant. Considering that common cleaning agents contain 20% to 40% by weight of surfactant, the proportion of surfactant in the present cleaning composition is small.

As sodium salts, this embodiment contains sodium bicarbonate, anhydrous sodium carbonate, and sodium chloride.

Next, a method of using the cleaning composition described above will be described. First, how to use the first embodiment will be described. The method of use of the first embodiment is to perform an immersion/stirring step of immersing and stirring a solid object to be treated in water to which a cleaning composition has been added.

Specifically, a case where the object to be treated is soil contaminated with radioactive cesium will be exemplified. Due to the accident at the Fukushima nuclear power plant that occurred during the Great East Japan Earthquake in 2011, radioactive substances were released into the environment, and a large amount of soil was contaminated with radioactive substances. In general, radioactive waste discharged from nuclear power plants, etc., is stored for a long period of time in a sealed container or structure that shields radiation until the concentration of radioactive materials falls below the standard value. . However, when the amount of contaminated soil is large, it is extremely difficult to seal it in a container or structure that shields radiation and to store it for a long period of time. Therefore, there is a strong demand for a technique for treating soil contaminated with radioactive substances to reduce the concentration of radioactive substances to a level that can be discharged into nature.

It is said that most of the radionuclides in soil contaminated with radioactive substances are cesium 134 or cesium 137. In particular, cesium 137 has a long half-life of about 30 years, so it affects the environment and the human body over a long period of time. . Therefore, it is urgent to establish a method to reduce the concentration of radioactive cesium in contaminated soil.

In the method of use of the first embodiment in which the object to be treated is soil contaminated with radioactive cesium, a purification aqueous medium, which is water to which a purification composition has been added, is contaminated with radioactive cesium, which is the object to be treated. In addition to the soaking/stirring step of soaking and stirring the soil, the separation step and the filtering step are further provided.

In the immersion/stirring step, the purification composition is added to water to form an aqueous medium for purification, which is introduced into a stirring tank together with soil contaminated with radioactive cesium, and stirred at room temperature. The stirring tank is provided with stirring blades driven by a motor. As the "water" to which the cleaning composition is added, tap water, well water, rain water, and river water can be used.

The pH of the purification aqueous medium, which is water to which the purification composition has been added, is adjusted to 9.0 to 10.5. The aqueous solution of sodium bicarbonate and sodium carbonate contained in the cleaning composition exhibits weak alkalinity. In addition, an aqueous solution containing components eluted from baked scallop shell powder, which is baked shell powder, exhibits strong alkalinity. In this embodiment, the citric acid contained in the purification composition adjusts the pH of the purification aqueous medium.

It is considered that the following phenomenon occurs in such a stirring process. Radioactive cesium is believed to be firmly held in the clay contained in the soil. Clay minerals consist of a tetrahedral unit layer in which silicon and oxygen tetrahedra are bonded two-dimensionally, and an octahedral unit layer in which octahedrons in which oxygen ions or hydroxide ions are hexacoordinated to aluminum are two-dimensionally bonded. The combination of these unit layers varies depending on the type of clay mineral such as kaolinite, pyrophyllite, muscovite, montmorillonite, and chlorite. By substituting aluminum for part of the silicon in the tetrahedral unit layer and by substituting silicon for aluminum in the octahedral unit layer, the unit layer is negatively charged, so that the charge is neutralized. Cations such as potassium, sodium and calcium ions are held between the unit layers. In contaminated soil, it is thought that radioactive cesium ions are retained between unit layers in place of these cations.

When contaminated soil is agitated in water containing a purification composition (aqueous purification medium), the action of the surfactant contained in the purification composition causes the clay particles to be incorporated into the micelles, resulting in an aqueous purification medium. disperse to A large number of sodium ions are present in the aqueous cleaning medium due to the dissolution of sodium salts contained in the cleaning composition. Therefore, the cations held between the unit layers in the clay particles for charge neutralization are easily ion-exchanged with the sodium ions dissolved in the purification aqueous medium. Cesium, like sodium, is an alkali metal and has the same valence. Therefore, the radioactive cesium ions retained in the clay particles are ion-exchanged with sodium ions in the purification aqueous medium and are eluted into the purification aqueous medium.

On the other hand, the maifan stone contained in the purification composition has the property of ion-exchanging cations as described above, but since a large number of sodium ions supplied from the sodium salt already exist in the purification aqueous medium, Potassium ions and calcium ions, which are other ion species, are preferentially eluted from maifanseki. Potassium, like cesium, is an alkali metal and has the same valence, so the eluted potassium ions undergo ion exchange with the radioactive cesium ions held in the dispersed clay particles, and the radioactive cesium ions enter the water purification medium. Elute.

Due to ion exchange with sodium ions and potassium ions, the cesium ions eluted in the purification aqueous medium are retained in the maifanseki eluted with potassium ions and calcium ions for charge compensation.

As described above, the method of use of the present embodiment focuses on the ion-exchange capacity of maifanseki, and one of its features is to "stir powder of maifanseki together with contaminated soil in water". Conventionally, maifanseki has been used to treat polluted soil, but it was used as a filtering material focusing on the porosity of maifanseki. In this embodiment, maifanseki is used as one of the components of the cleaning composition that is stirred in water together with the contaminated soil, rather than as a filter medium.

The radioactive cesium ions eluted in the aqueous medium for purification are considered to be adsorbed not only by the maifanseki but also by the porous calcined shell powder. In addition, the cesium ions eluted into the purification aqueous medium form a chelate with citric acid contained in the purification composition. Since the chelate is bulky in volume, it is not ion-exchanged again with the cation held between the unit layers in the clay particles. On the other hand, on the surface of the maifanseki powder, since there is no spatial restriction, even cesium ions forming chelates are retained for charge compensation. Therefore, the radioactive cesium contained in the soil migrates to the maifanseki powder and the fired shell powder through the soaking and stirring processes. As described above, in the present embodiment, the citric acid contained in the purification composition exerts the effect of adjusting the pH of the purification aqueous medium and the effect of generating cesium ions and chelates.

In the separation step, the rotation of the stirring blade is stopped and left to stand still. As a result, the soil slightly containing the water medium for purification settles on the bottom of the agitation tank. On the other hand, the maifanseki powder and the calcined shell powder carrying radioactive cesium can be suspended in the purification aqueous medium due to their fineness and the action of the surfactant contained in the purification composition. is separated from the soil. Therefore, only the water medium for purification in which the calcined shell powder and the malfanseki powder are suspended is discharged from the stirring tank and subjected to the filtration process.

In the filtration step, the purification aqueous medium that has undergone the separation step is passed through a filtration layer filled with a filtration material. As a result, the maifanseki powder and the calcined shell powder carrying radioactive cesium are collected by the filtering material. A plurality of filter layers with different types of filter media can be provided, and by passing through the plurality of filter layers, the maifan stone powder and the calcined shell powder that carry radioactive cesium can be collected more reliably. can. As a result, the material containing radioactive cesium is changed from soil to filtering material, and the volume is greatly reduced. In addition, the radioactive cesium ions that remain unsupported by the powdered maifanseki and the powdered calcined seashells as they are eluted from the contaminated soil into the water purification medium are also absorbed by the filter media through the filtration process using multiple filtration layers. is considered to be Examples of filtering materials include nonwoven fabrics, porous ceramics such as zeolite, and activated carbon.

Since the concentration of radioactive cesium in the water that has passed through the filtering material (hereinafter referred to as "treated water") is below the detection limit as described later, the treated water can be discharged into nature.

Here, calcium oxide, which is the main component of the calcined shell powder, becomes calcium hydroxide by hydration and partly dissolves in water (the solubility of calcium hydroxide in water is about 0.16 at 20 ° C.). It is thought that there is also a component that dissolves into water from the calcined shell powder. As will be described later, components eluted from the baked shell powder into water have sterilizing and antibacterial effects. Therefore, even if the water used for the purification aqueous medium is, for example, river water and contains some kind of bacteria, the water after treatment is treated by the action of the components eluted from the baked shell powder. It can be discharged into the natural world in a state in which bacteria are sterilized and the growth of bacteria is suppressed. In addition, due to the sterilization and antibacterial action of the components eluted from the baked shell powder, the soil subjected to the treatment is also sterilized and the growth of bacteria is suppressed, so the generation of odor can be suppressed.

The soil remediation process, which is performed in the order of agitation, separation, and filtration, can be performed multiple times on contaminated soil, thereby further reducing the concentration of radioactive cesium in the sludge after treatment. can. When the soil remediation process is performed multiple times, the water that has passed through the filtration layer in the previous filtration process (water after treatment) is used as the "water" to which the remediation composition is added in the agitation process in the next treatment process. can be used. By doing so, it is possible to reduce the amount of treated water that is finally discharged into nature. As described above, since the calcined shell powder is contained in the purification composition, the aqueous medium for purification is sterilized, so even if it is circulated and used in multiple soil purification steps, bacteria will grow. Fear is reduced.

The soil in which the concentration of radioactive cesium has been reduced through the soil remediation process as described above is separated from the suspension in the separation process, and then solidified by mixing with a hardening agent. The solidified soil can be used as a roadbed material or the like.

Actually, the above soil remediation process was carried out at a rate of 11 liters of water and 2 grams of the remediation composition per 1 kg of soil (collected in Fukushima Prefecture) contaminated with radioactive cesium. Concentrations of cesium-134 and cesium-137 were measured in the soil before treatment and in the soil after one treatment. For the measurement, a gamma ray spectrometer NaI (TI) scintillation spectrometer (FNF-401, manufactured by OYO Koken Kogyo Co., Ltd.) was used. The results are shown in Table 1.

As shown in Table 1, one soil remediation process significantly reduced the concentration of radioactive cesium in the contaminated soil, approximately one-half. By performing the soil remediation process twice or more, the concentration of radioactive cesium in the soil can be further reduced.

In addition, when the concentrations of cesium 134 and cesium 137 were measured in the same manner for water after one soil remediation step, both were below the detection limit.

Next, how to use the second embodiment will be described. The method of use of the second embodiment is to add the cleaning composition to a liquid object to be treated and stir it. In practice, water contaminated with radioactive cesium was used as an object to be treated, and 2 grams of the cleaning composition was added to 12 liters of the contaminated water for purification. Concentrations of cesium-134 and cesium-137 were measured in the water before treatment and in the water after treatment from which the malfanseki powder and the calcined shell powder were removed by passing through the above filter layer. For the measurement, a germanium semiconductor detector (GEM25-70-XLB-C manufactured by ORTEC) was used, and the measurement was performed for 70000 seconds or longer. The results are shown in Table 2.

As can be seen from Table 2, the concentration of radioactive cesium contained in the contaminated water was reduced to below the detection limit after the purification treatment using the purification composition. This is considered to be the result of ion exchange in which potassium ions are eluted from maifanseki as cations other than sodium ions, and radioactive cesium ions in the water are retained in maifanseki instead of potassium ions. Radioactive cesium ions in water were also considered to be removed from the system by being adsorbed by porous calcined shell powder.

In addition, the concentration of heavy metals was measured for the same water before purification treatment and water after purification treatment. The results are shown in Table 3 together with the measurement method.

As is clear from Table 3, the concentrations of heavy metals in polluted water were also greatly reduced to levels below the detection limit through purification treatment using the cleaning composition. This is also considered to be the result of ion exchange in which cations other than sodium ions are eluted from maifanseki, and heavy metal cations in water are retained in maifanseki in place of the ions. Since maifanseki can exchange cations with different valences such as potassium ions, calcium ions, and magnesium ions, even if multiple types of heavy metal cations with different valences exist in the water to be treated, , was thought to be retained in Maifanseki for charge compensation. In addition, it was considered that heavy metal cations in water, which is the material to be treated, were also removed from the system by being adsorbed by the porous calcined shell powder.

Based on these results, even if the material to be treated is soil contaminated with heavy metals, it is possible to remove radioactive cesium-contaminated soil by carrying out purification treatment in the order of the immersion/agitation process, separation process, and filtration process. It was thought that the concentration of heavy metals in soil could be reduced by the same mechanism as in the case.

Next, it will be shown that water in which the cleaning composition of the present embodiment is dispersed has sterilization and antibacterial effects. A test sample in which water in which a cleaning composition was dispersed was added to a medium in which a plurality of types of viable bacterial solutions were ingested, and a control sample without addition were stored and cultured at a temperature of 25°C. Viable cell counts were measured over time. Table 4 shows the results. In the control sample, the liquid added instead of the water in which the cleaning composition was dispersed was physiological saline for Staphylococcus aureus, 3% sodium chloride solution for Vibrio parahaemolyticus, and other bacteria. Purified water was used.

As shown in Table 4, for all bacteria, the number of viable bacteria in the control sample was about the same as at the start even after 30 minutes, whereas water in which the cleaning composition was dispersed was applied. Specimens had depleted viable counts to below detection limits by at least 30 minutes. From this, it can be seen that the cleaning composition of the present embodiment has sterilization and antibacterial effects.

As described above, according to the present embodiment, a new cleaning composition that can effectively utilize seashells as a resource is capable of purification treatment to remove contaminants from the object to be treated, and has a sterilization and antibacterial effect. It is possible to provide a cleaning composition having In addition, it is possible to provide a method of using a cleaning composition that can effectively perform purification treatment depending on the type of object to be treated.

As described above, the present invention has been described with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and as shown below, various improvements can be made without departing from the scope of the present invention. and design changes are possible.

For example, in the above-described embodiments, the case where the object to be treated is contaminated soil or contaminated water has been exemplified, but there are various other applications, such as machine parts to which metal scraps are adhered, and clothing to which rust stains are adhered. can be used as the object to be processed. In addition, when the object to be treated is a machine part, clothes, or the like, a rinsing step of washing the object to be treated with fresh water can be performed after the purification treatment. By performing the rinsing step, it is possible to reduce the possibility that the powder of the malt stone or the powder of the fired shell remains on the surface of the object after washing.

Claims (4)

Baked shell powder with an average particle size of 5 μm to 10 μm,
malfan stone powder and
a surfactant;
citric acid;
A cleansing composition comprising: a sodium salt; To the water to which the cleaning composition according to claim 1 is added,
A method for using a cleaning composition, characterized by immersing a solid object to be treated, or stirring the solid object to be treated while immersing it. 3. The method of using a cleaning composition according to claim 2, wherein the object to be treated is at least one of soil contaminated with radioactive cesium and soil contaminated with heavy metals. The cleaning composition according to claim 1 is added to a liquid object and stirred,
A method of using a cleaning composition, wherein the object to be treated is at least one of water contaminated with radioactive cesium and water contaminated with heavy metals.