WO2020116841A1 - Decontamination agent for radioactive cesium and method of water depth-adjustable decontamination of radioactive cesium - Google Patents

Abstract

The present invention provides a decontamination agent for radioactive cesium, which is a composition comprising clay minerals and a foaming agent, and adsorbs or removes radioactive cesium, wherein the foaming speed of the decontamination agent can be adjusted depending on the depth of water by adjusting the clay minerals content and the foaming agent content. Consequently, the present invention includes a technical concept of maximizing the horizontal dispersion performance of a decontamination agent for radioactive cesium, such as zeolite, etc., through adjustment of the settling speed thereof, and thus proposes a new model in the field of underwater radioactive cesium decontamination.

Description

Radioactive cesium decontamination agent and depth-customized radioactive cesium decontamination method using the same

The present technology relates to a technology for decontamination of pollutants in water, and in particular, a technology for decontamination agents and decontamination methods capable of efficiently decontaminating radioactive cesium present in water for various water depths.

In March 2011, the Fukushima nuclear power plant accident in Japan caused serious environmental problems because soil, animals, plants, and waste were contaminated with radioactive materials. Radioactive iodine and radioactive cesium are the main radioactive materials generated in nuclear power plant accidents. Radioactive iodine has a relatively short half-life of about 8 days, whereas radioactive cesium has a very long half-life of 30 years, and cesium has similar chemical properties to potassium, so it is concentrated in the muscles when absorbed and lacks immunity and various cancers (infertility, bone marrow cancer, lung cancer, thyroid cancer) , Breast cancer, etc.).

In order to remove contaminants such as radioactive cesium, a mineral such as zeolite must directly contact the contaminants. If radioactive cesium is introduced into a fixed capacity, such as a water treatment plant, there will be no problem with contact between zeolite and cesium. However, where the capacity is not fixed, such as a lake, there will be a limit of contact by relying on spraying on the water surface. Can be. In addition, since the zeolite has a specific gravity of 2.0-2.4, the sedimentation rate in water may be high, so it may not have a sufficient residence time to react with radioactive cesium. In addition, in relatively large freshwater bodies such as the Paldang Lake, the depth is up to 23m and the depth is 6m on average. In this case, there is a possibility that the pollutants in the water are not homogeneously distributed by depth due to stratification due to changes in water temperature. .

The present invention has been devised to solve the problems of the prior art so that the decontamination agent has a sufficient residence time and the dispersion in the horizontal direction can be effectively performed in a situation where contaminants can be unevenly distributed according to depths according to the water system scale. It is an object of the present invention to provide a radioactive cesium decontamination agent capable of decontaminating radioactive cesium at a water depth.

In addition, an object of the present invention is to provide a method for decontaminating radioactive cesium that can efficiently decontaminate radioactive cesium in water by using the radioactive cesium decontamination agent.

Hereinafter, various embodiments described herein are described with reference to the drawings. In the following description, for the full understanding of the present invention, various specific details, such as specific forms, compositions and processes, have been described. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and forms. In other instances, well-known processes and manufacturing techniques are not described in specific details in order not to unnecessarily obscure the present invention. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, form, composition or characteristic described in connection with the embodiment is included in one or more embodiments of the invention. Thus, the context of “in one embodiment” or “an embodiment” expressed in various places throughout this specification does not necessarily represent the same embodiment of the invention. Additionally, special features, shapes, compositions, or properties can be combined in any suitable way in one or more embodiments.

Unless otherwise specified in the present invention, all scientific and technical terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains.

In the present invention, "radioactive material" is a major pollutant generated during a nuclear accident. Currently, in a widely used nuclear power plant, nuclear fission in a nuclear reactor involves the production of a significant amount of radioactive by-products. The radioactive materials mainly contain iodine 131, cesium 134, cesium 137, cerium 144, rhodium 106, cobalt 60, strontium 90, radium 226, uranium 234, uranium 235, uranium 238, and plutonium 239. It may be a nuclear fission product and an active element including a radioactive isotope, but is not limited thereto.

In the present invention, contaminated water may mean an aqueous solution in which radioactive materials are dissolved. When a nuclear accident occurs, a highly volatile radioactive material vaporizes and moves into the atmosphere at the beginning of a serious accident, and may enter the surface environment through radioactive fallout or rainfall. In the contaminated water, radioactive materials such as radioactive cesium are dissolved in ionic form. It may contain strong binding to clay and organic matter.

In the present invention, zeolite (zeolite) is a group of minerals belonging to the reticular silicate mineral, it is known to have a high removal efficiency for various contaminants because it has a very large number of nanometer pores inside. It can absorb and remove moisture and odors, and can be used as a material for ion exchangers because it can trap heavy metals. In particular, natural zeolite is mostly collected in the form of “zeolitic tuff” in which fine-grained tuff is denatured, and hydrous silicate containing a small amount of Na, K, Ca, Mg, Sr or Ba as cations in terms of chemical composition. As a mineral, the types are clinoptilolite, mordenite, heulandite, phillipsite, erionite, chabazite and ferririte ( ferrierite) and the like, but is not limited thereto.

In the present invention, sodium hydrogen carbonate generates voids or pores due to HCO3 gas generation in the decomposition process by heat during drying, and Na+ remains in the adsorbent even after firing and may help to form a structural force. In addition, in the process of forming the pores or pores, natural zeolite, citric acid, and corn starch may serve to adhere or adhere to the adsorbent of the present invention without coating.

The corn starch of the present invention may be amylose-containing starch extracted from corn, but is not limited thereto. Alternatively, a mixture of starch, such as a combination of high amylose corn starch and corn starch, can be used. The corn of the present invention may be obtained in a standard mating technique including intact or any other gene or chromosomal manipulation method including breeding breeding, translocation, inversion, transformation or variation thereof, but is not limited to this. .

The starch of the present invention is manufactured by a physical treatment process including extrusion molding, voltage axis, cooking of starch slurry, spray drying, and fluidized bed agglomeration, but is not limited thereto. In one embodiment, the process can be an extrusion process. The starch is treated to be partially pregelatinized, producing starch particles having gelatinized and non-enriched moieties. In one embodiment, the gelatinized starch essentially binds non-enriched particles (ie, granules) together. Corn starch in the present invention may serve to make the formulation of the decontamination agent constant.

According to an embodiment of the present invention, as a decontamination agent for removing radioactive substances contained in contaminated water, zeolite; Sodium hydrogen carbonate; And a decontamination agent for radioactive contaminants comprising citric acid.

In the present invention, the decontamination agent is 30 to 60% by weight of zeolite; Sodium hydrogen carbonate 20-40% by weight; And 10 to 40% by weight of citric acid, but is not limited thereto.

In the present invention, the decontamination agent is 40 to 60% by weight of zeolite; Sodium hydrogen carbonate 20-40% by weight; And it contains 10 to 20% by weight of citric acid, and may be intended to remove the radioactive material contained in the middle layer water system, but is not limited thereto.

In the present invention, the decontamination agent is 30 to 40% by weight of zeolite; Sodium hydrogen carbonate 30-40% by weight; And 20 to 40% by weight of citric acid, may be intended to remove the radioactive material contained in the deep water system, but is not limited thereto.

In the present invention, the decontamination agent may further include corn starch, preferably, the corn starch may be 5 to 20% by weight, but is not limited thereto.

In the present invention, the decontamination agent may include zeolite, sodium hydrogen carbonate, citric acid and corn starch in a weight ratio of 2: 1-2: 0.5-1: 0.25-1, but is not limited thereto.

In the present invention, the decontamination agent may include zeolite, sodium hydrogen carbonate, citric acid, and corn starch in a weight ratio of 2:1:0.5:0.5, and the decontamination agent is for removing radioactive substances contained in the middle layer aqueous system. However, it is not limited thereto.

In the present invention, the decontamination agent includes zeolite, sodium hydrogen carbonate, citric acid and corn starch in a weight ratio of 2:1:0.5:0.25, and the decontamination agent may be for removing radioactive substances contained in the deep water system. However, it is not limited thereto.

In the present invention, the zeolite may be one containing 50-60% by weight of heliumite and 40-50% by weight of mordenite, but is not limited thereto.

In the present invention, the zeolite may have a specific surface area of 50 to 70 m ² /g, an average pore volume of 0.1 to 0.15 ml/g, an average pore size of 5 to 15 nm, or a cation exchange capacity of 60 to 120 meq/100 g. However, it is not limited thereto.

The radioactive cesium decontamination agent according to an embodiment of the present invention includes clay minerals such as zeolite for adsorption of radioactive cesium, and at the same time contains a foaming component. The rate of foaming can be adjusted. Through this, it is possible to adjust the speed or point of expression of the decontamination effect according to various depths or water depths, so that it is possible to tailor decontamination corresponding to various depths of the water system. This means that radioactive cesium contaminants present in all depths can be decontaminated closely, thereby maximizing the decontamination efficiency of radioactive cesium in water.

Therefore, in the aqueous system contaminated with radioactive cesium, the decontamination agent can be applied to various horizontal areas, and at the same time, the decontamination agent of various compositions can exhibit a uniform decontamination effect in horizontal and vertical areas.

However, the unit weight and unit capacity of the decontamination agent may be variously modified in consideration of the capacity, area, and depth of the water system.

In the end, the present invention proposes a new model in the field of radioactive cesium decontamination in water by including a technical idea of maximizing the horizontal dispersion performance by controlling the sedimentation speed of zeolite, which is a radioactive cesium decontaminant.

Figure 1a is a graph showing the results of X-ray diffraction analysis for a zeolite (ZG) sample, Figure 1b is a graph showing the results of X-ray diffraction analysis for a Gyeongju zeolite (KGZ) sample, Figure 1c is Pohang zeolite (KPZ) It is a graph showing the results of X-ray diffraction analysis of the sample.

Figure 2 is a graph showing the results of low concentration cesium (Cw ≒50 µg/L) adsorption distribution coefficient for various clay minerals.

3 is a schematic view showing a large column tank.

4 is a graph showing the results of a 40L water tank preliminary experiment.

5A to 5F are graphs showing changes in turbidity concentration over time by a zeolite powder type decontamination agent. Figure 5a is a graph showing the change in turbidity concentration after 1 minute by the zeolite powder type decontamination agent, Figure 5b is a graph showing the change in turbidity concentration after 3 minutes by the zeolite powder type decontamination agent, Figure 5c is a zeolite powder type It is a graph showing the change in turbidity concentration after 10 minutes by the decontamination agent, and FIG. 5D is a graph showing the change in turbidity concentration after 60 minutes by the zeolite powder type decontamination agent, and FIG. 5D is 120 minutes by the zeolite powder type decontamination agent. It is a graph showing the change in turbidity concentration after, and FIG. 5F is a graph showing the change in turbidity concentration after 1440 minutes by the zeolite powder type decontamination agent.

6A to 6F are graphs showing changes in cesium concentration over time by a zeolite powder-type decontamination agent. Figure 6a is a graph showing the change in cesium concentration after 1 minute by the zeolite powder type decontamination agent, Figure 6b is a graph showing the change in cesium concentration after 3 minutes by the zeolite powder type decontamination agent, Figure 6c is a zeolite powder type A graph showing the change in cesium concentration after 10 minutes by the decontamination agent, and FIG. 6D is a graph showing the change in cesium concentration after 60 minutes by the zeolite powder type decontamination agent, and FIG. 6D is 120 minutes by the zeolite powder type decontamination agent. It is a graph showing a change in cesium concentration afterwards, and FIG. 6F is a graph showing a change in cesium concentration after 1440 minutes by a zeolite powder type decontamination agent.

7A to 7F are graphs showing changes in turbidity concentration over time by the decontamination agent of Example 1; Figure 7a is a graph showing the turbidity concentration change after 1 minute by the decontamination agent of Example 1, Figure 7b is a graph showing the turbidity concentration change after 3 minutes by the decontamination agent of Example 1, Figure 7c is an implementation Example 1 is a graph showing the turbidity concentration change after 10 minutes by the decontamination agent, Figure 7d is a graph showing the turbidity concentration change after 60 minutes by the decontamination agent of Example 1, Figure 7d is the decontamination of Example 1 It is a graph showing the change in turbidity concentration after 120 minutes by the agent, and FIG. 7F is a graph showing the change in turbidity concentration after 1440 minutes by the decontamination agent of Example 1.

8A to 8F are graphs showing changes in cesium concentration over time by the decontamination agent of Example 1; Figure 8a is a graph showing the change in cesium concentration after 1 minute by the decontamination agent of Example 1, Figure 8b is a graph showing the change in cesium concentration after 3 minutes by the decontamination agent of Example 1, Figure 8c is carried out Graph showing the change in cesium concentration after 10 minutes by the decontamination agent of Example 1, Figure 8d is a graph showing the change in cesium concentration after 60 minutes by the decontamination agent of Example 1, Figure 8d is the decontamination of Example 1 It is a graph showing the change in cesium concentration after 120 minutes by the agent, and FIG. 8F is a graph showing the change in cesium concentration after 1440 minutes by the decontamination agent of Example 1.

9A to 9F are graphs showing changes in turbidity concentration over time by the decontamination agent of Example 2; Figure 9a is a graph showing the change in turbidity concentration after 1 minute by the decontamination agent of Example 2, Figure 9b is a graph showing the change in turbidity concentration after 3 minutes by the decontamination agent of Example 2, Figure 9c is an implementation Graph showing the change in turbidity concentration after 10 minutes by the decontamination agent of Example 2, Figure 9d is a graph showing the change in turbidity concentration after 60 minutes by the decontamination agent of Example 2, Figure 9d is the decontamination of Example 2 It is a graph showing the change in turbidity concentration after 120 minutes by the agent, and FIG. 9F is a graph showing the change in turbidity concentration after 1440 minutes by the decontamination agent of Example 2.

10A to 10F are graphs showing changes in cesium concentration over time by the decontamination agent of Example 2; Figure 10a is a graph showing the change in cesium concentration after 1 minute by the decontamination agent of Example 2, Figure 10b is a graph showing the change in cesium concentration after 3 minutes by the decontamination agent of Example 2, Figure 10c is an implementation Graph showing the change in cesium concentration after 10 minutes by the decontamination agent of Example 2, Figure 10d is a graph showing the change in cesium concentration after 60 minutes by the decontamination agent of Example 2, Figure 10d is the decontamination of Example 2 It is a graph showing the change in cesium concentration after 120 minutes by the agent, and FIG. 10F is a graph showing the change in cesium concentration after 1440 minutes by the decontamination agent of Example 2.

Figure 11a shows an embodiment of the formulation of the decontamination agent of Example 1 and Example 2, Figure 11b shows an embodiment of the formulation of the decontamination agent of Example 3 and Example 4.

12A to 12D show the dispersion pattern over time for the decontamination agent of Example 3. FIG. 12A shows the dispersion pattern after 2 seconds after administration of the anti-inflammatory agent of Example 3, FIG. 12B shows the dispersion pattern after 8 seconds after administration of the anti-inflammatory agent of Example 3, and FIG. 12C shows 20 after administration of the anti-inflammatory agent. It shows the dispersion pattern after the lapse of seconds, and FIG. 12D shows the dispersion pattern after 40 seconds after the administration of the anti-inflammatory agent of Example 3.

13A to 13D show the dispersion pattern over time for the decontamination agent of Example 4. Figure 13a shows the dispersion pattern after 2 seconds after administration of the anti-inflammatory agent of Example 4, Figure 13b shows the dispersion pattern after 5 seconds after administration of the anti-inflammatory agent of Example 4, Figure 13c is the decontamination of Example 4 The dispersion pattern is shown after 20 seconds after the first administration, and FIG. 13D shows the dispersion pattern after 40 seconds after the administration of the anti-inflammatory agent of Example 4.

14A to 14C show the dispersion pattern over time for the decontamination agent of Comparative Example 11. 14A shows the dispersion pattern after 4 seconds after administration of the decontamination agent of Comparative Example 11, FIG. 14B shows the dispersion pattern after 20 seconds after administration of the decontamination agent of Comparative Example 11, and FIG. 14C shows the decontamination of Comparative Example 11 It shows the dispersion pattern after 60 seconds after the first administration.

15a to 15c show the dispersion pattern over time for the decontamination agent of Comparative Example 12. 15A shows the dispersion pattern after 2 seconds after administration of the decontamination agent of Comparative Example 12, FIG. 15B shows the dispersion pattern after 5 seconds after administration of the decontamination agent of Comparative Example 12, and FIG. 15C shows the decontamination of Comparative Example 12 It shows the dispersion pattern after 70 seconds after the first administration.

16A to 16D show the dispersion pattern over time for the decontamination agent of Comparative Example 13. Figure 16a shows the dispersion pattern after 4 seconds after administration of the anti-inflammatory agent, Figure 16b shows the dispersion pattern after 8 seconds after administration of the anti-inflammatory agent of Comparative Example 13, Figure 16c is dispersed after 20 seconds after the administration of the anti-inflammatory agent It shows the aspect.

Figure 17a has the same blending ratio as in Example 3, showing the appearance of 15 seconds after dropping the decontamination agent prepared in a formulation of 10g to 0 ℃ (left), 20 ℃ (right) in two different temperature tanks .

FIG. 17B shows the appearance of 15 seconds after dropping the decontamination agent produced at 12 g to 0° C. (left) and 20° C. (right) with the same mixing ratio as in Example 4 in two different water tanks.

18A is an embodiment of the present invention, and shows the desorption rate divided into low and high concentrations from 14 days to about 70 days to examine the desorption effect of illite according to temperature and concentration over time.

18B is an embodiment of the present invention, and shows the desorption rate divided into low and high concentrations from 14 to about 70 days to examine the desorption effect of zeolite according to temperature and concentration over time.

According to an embodiment of the present invention, as a decontamination agent for removing radioactive substances contained in contaminated water, zeolite; Sodium hydrogen carbonate; And a decontamination agent for radioactive contaminants comprising citric acid.

Hereinafter, the radioactive cesium decontamination agent of the present invention and the depth-customized radioactive cesium decontamination method using the same will be described in detail through the accompanying drawings and experimental data. However, the following descriptions are exemplary descriptions to help understanding of the present invention, and the technical idea of the present invention is not limited by the following descriptions. The technical spirit of the present invention may be interpreted or limited only by the claims below.

[Preparation example] Preparation of sample for decontamination agent

Natural zeolite samples (ZG) were selected as the base material for radioactive cesium decontaminants. 1A is a graph showing X-ray diffraction analysis results for a zeolite (ZG) sample. The origin of zeolite was selected as a sample produced in Gyeongju, Gyeongbuk. Among the commercially available Gyeongju Zeolite (KGZ) products, the most widely sold products with a particle diameter of 45 μm were purchased. In addition, Table 1 below is a table showing the composition ratio of the constituent components (minerals) identified according to the diffraction analysis results. Referring to FIG. 1A and Table 1, X-ray diffraction analysis confirmed that the minerals belonging to zeolite were composed of heliumite and mordenite, and the composition ratio was about 53% of heulandite and mordenite ( Mordenite) consisted of about 47%.

Pohang, preferably Pohang zeolite (KPZ), produced in Yeongil Bay, Pohang, is also composed of heliumite and mordenite, and has similar characteristics to Gyeongju zeolite (KGZ). Figure 1b is a graph showing the results of X-ray diffraction analysis of the Gyeongju zeolite sample, Figure 1c is a graph showing the results of X-ray diffraction analysis of the Pohang zeolite sample. The composition ratio of Gyeongju zeolite and Pohang zeolite is slightly different, as shown in Table 1, but the results of X-ray diffraction analysis show generally similar peak shapes (FIGS. 1B and 1C). The specific surface area of the zeolite was found to have a very small particle size of about 60 m ² /g, and the cation exchange capacity was about 72 to 100 meq/100 g, indicating a very high value compared to the comparative Youngdong Illite (Table 2). . In particular, the specific surface area and cation exchange capacity can act as factors affecting the difference in adsorption capacity.

sample	Heulandite content (%)	Mordenite content (%)
Gyeongju Zeolite (KGZ)	53	47
Pohang Zeolite (KPZ)	64	36

Mineralogy properties of zeolite (ZG) samples

Table 2 shows the results of evaluating the mineralogical properties of the prepared zeolite samples. FIG. 2 is a graph showing the result of adsorption distribution coefficient of low concentration cesium (Cw ≒50 µg/L) for various clay minerals. In addition, Table 3 is a table in which the absorption distribution coefficient of each mineral is quantified and displayed. Referring to Table 2, Table 3, and FIG. 2, the specific surface area of ZG was about 65 m ² per 1 g, and the cation exchange capacity was high at about 100 meq/100 g. As a result of the small-scale adsorption experiment performed using 50 mL vial, the partition coefficient (K _d ) for cesium was very high, about 600,000 L/kg, and this value was about 100 to 1000 times higher than other minerals. The main adsorption mechanism in the zeolite is a cation exchange reaction occurring in the pores, and it can be interpreted that the high specific surface area and the cation exchange capacity of the zeolite contributed to increasing the cesium removal rate of the zeolite.

sample	Specific surface area (m2/g)	Average pore volume (mL/g)	Average pore size (nm)	Cation exchange capacity (meq/100g)
Gyeongju Zeolite (KGZ)	64.6	0.13	7.9	100.6
Pohang Zeolite (KPZ)	59	0.13	9	72
Yeongdong Industrial Illite (KYI)	4	0.02	22	5

Mineral	Average K d
Gyeongju Zeolite (KGZ)	600,000
Pohang Zeolite (KPZ)	150,000
Sericite	600
Illite	4,000
Bentonite	7,000

18A is an embodiment of the present invention, and shows the desorption rate divided into low and high concentrations from 14 days to about 70 days to examine the desorption effect of illite according to temperature and concentration over time.

18B is an embodiment of the present invention, and shows the desorption rate divided into low and high concentrations from 14 to about 70 days to examine the desorption effect of zeolite according to temperature and concentration over time.

As a result of examining the desorption effect of illite and zeolite according to concentration over time, it was found that the desorption degree of both minerals did not change significantly with time, and most of the desorption occurred at the beginning of the reaction. Illite exhibited a desorption rate of about 20% at low concentrations and about 50% at high concentrations, and no difference in desorption characteristics with temperature was observed. What is remarkable was that the desorption rate increased with time at a high concentration. The zeolite showed a relatively low concentration of desorption, but in all cases, the desorption rate was less than 1%, showing very good adsorption stability.

In this preparation example, only zeolite is illustrated as a clay mineral used as a decontamination agent, but it is natural that the use of other minerals such as illite, bentonite and sericite is also within the scope of the technical idea of the present invention. In addition, the minerals may be used as a mixed mineral of a plurality of types depending on the applied water system.

Field simulation experiment

Existing indoor experiments confirming the adsorption efficiency of cesium using natural minerals such as zeolite were continuously stirred using a small volume of 50 mL vial so that zeolite and cesium in the vial reacted as homogeneously as possible. This method has the advantage that the theoretical maximum cesium adsorption performance (Qm, single plane maximum adsorption, Langmuir model) and adsorption efficiency can be obtained. However, in the actual site where a decontamination agent such as zeolite is sprayed, 100% contact is not possible as in the experimental environment. 3 is a schematic view showing a large column tank. Referring to Figure 3, in order to check the dispersion of the decontamination agent by distance and depth in the spray area in the water tank and cesium removal efficiency, a pipe for sampling with acrylic was manufactured and installed. The diameter of the pipe for sampling was 20 mm (inner diameter 14 mm), and the total extension length was 1.7 m. 5 cm apart from the floor so that water samples could be introduced in 30 cm increments, and then installed a total of 4 sections of a 5 cm long screen at 30 cm intervals. After filling 1 ton of water in the water tank, the main cations (Ca, Mg, Na and K) and the main anions (Cl, SO4, HCO3) are added to reflect the competitive ion effects that can occur in the actual site. It was adjusted to be similar to the water quality of Paldang Lake, and was homogeneously matched with low concentration of cesium (about 50 μg/L). Then, the turbidity and cesium removal efficiency was confirmed by adding a decontamination agent.

Before spraying the decontamination agent, a water quality sample was collected to confirm the initial water quality using a peristaltic pump, and then a decontamination agent was added and a sample was checked to confirm changes over time. At the time of sampling, about 25 mL was collected at a flow rate of 15 mL/min. The collected sample was first measured for turbidity, and then put into a centrifuge, centrifuged at 3500 rpm for 30 minutes, and the supernatant was collected. The supernatant was lowered to pH 2 or less using nitric acid and then stored at 4°C or lower, and cesium concentration was measured by ICP-MS.

The nuclides of cesium that can be used in this experiment are not limited. One factor in the movement of radionuclides in aquatic environments is the behavior of stable nuclides, so the stable behavior of cesium in aquatic environments may be used as a metaphor to predict the long-term effects of cesium 137 on the environment (Tiwari, Diwakar). & Lalhmunsiama, Lalhmunsiama & Choi, S. & Lee, Seung-Mok. (2014).Activated Sericite: An Efficient and Effective Natural Clay Material for Attenuation of Cesium from Aquatic Environment.Pedosphere. 24. 731-742.).

Powder type decontamination agent (powder type zeolite only)

A preliminary experiment was conducted in a 40L scale water tank to estimate the appropriate amount of zeolite required to remove radioactive cesium in water prior to the large scale 1 ton water tank experiment. As a result of preliminary experiments, considering both turbidity and cesium removal rate, it was found that when 2 g of zeolite was added at 40 L, cesium was most efficiently removed, which was selected as the basic design quantity. 4 is a graph showing the results of a 40L water tank preliminary experiment. Based on this, the amount of zeolite required for a 1-ton tank was 50 g.

Using the results of the preliminary experiments, 50 g of zeolite powder was added to a water tank containing 1 ton of cesium-contaminated water, and turbidity and cesium concentrations by time, location and depth were measured. 5A to 5F are graphs showing changes in turbidity concentration over time by a zeolite powder type decontamination agent. Figure 5a is a graph showing the change in turbidity concentration after 1 minute by the zeolite powder type decontamination agent, Figure 5b is a graph showing the change in turbidity concentration after 3 minutes by the zeolite powder type decontamination agent, Figure 5c is a zeolite powder type It is a graph showing the change in turbidity concentration after 10 minutes by the decontamination agent, and FIG. 5D is a graph showing the change in turbidity concentration after 60 minutes by the zeolite powder type decontamination agent, and FIG. 5D is 120 minutes by the zeolite powder type decontamination agent. It is a graph showing the change in turbidity concentration after, and FIG. 5F is a graph showing the change in turbidity concentration after 1440 minutes by the zeolite powder type decontamination agent.

5A to 5F, it was found that the zeolite powder reached the bottom of the water bath within 1 minute and tended to settle vertically rather than being horizontally dispersed.

6A to 6F are graphs showing changes in cesium concentration over time by a zeolite powder-type decontamination agent. Figure 6a is a graph showing the change in cesium concentration after 1 minute by the zeolite powder type decontamination agent, Figure 6b is a graph showing the change in cesium concentration after 3 minutes by the zeolite powder type decontamination agent, Figure 6c is a zeolite powder type A graph showing the change in cesium concentration after 10 minutes by the decontamination agent, and FIG. 6D is a graph showing the change in cesium concentration after 60 minutes by the zeolite powder type decontamination agent, and FIG. 6D is 120 minutes by the zeolite powder type decontamination agent. It is a graph showing a change in cesium concentration afterwards, and FIG. 6F is a graph showing a change in cesium concentration after 1440 minutes by a zeolite powder-type decontamination agent.

Referring to Figures 6a to 6f, the concentration of cesium in water also appears to decrease along the point of increasing turbidity, confirming that the decontamination effect is concentrated around the zeolite. This tendency was strongly observed between 1 and 3 minutes in the beginning of the experiment, and after 3 minutes, it was confirmed that the zeolite powder reached all the bottom, and after 10 minutes, the turbidity was first homogenized, and then gradually the homogenization of cesium concentration in water was achieved. . After 24 hours, the zeolite particles had settled on the floor to the extent that it was difficult to recover the water collecting channel through the metering pump. At this time, the final cesium removal rate was about 60%, similar at all points.

Depth-specific decontamination agent

When the above-described powder type zeolite was introduced into a water tank, it was confirmed that vertical dispersion was predominant and horizontal dispersion was hardly achieved due to the initial settling. When spraying a decontamination agent over a large area, if the horizontal dispersion of the decontamination agent is low, there is a disadvantage that more input points should be taken. As a component for foaming, sodium hydrogen carbonate (NaHCO3) and citric acid (C6H8O7) are components that can control the expression of zeolite, a decontamination component, by increasing the horizontal dispersion to control the foaming rate.

[Example 1] Preparation of radioactive cesium decontamination agent (for deep)

The foamed decontamination agent was mixed with a content of the main additives sodium hydrogen carbonate, citric acid and zeolite in an amount as shown in Table 4, and ethanol (C2H5OH) was used to mold them. The amount of zeolite injected based on 1 ton was applied equally to 50 g as the result of the previous preliminary experiment. Ethanol for mixing and molding the zeolite and other ancillary materials was injected at about 20% of the total decontamination agent mass, and put into a production mold to dry for 2 days or more in an oven set to 40°C to prepare a decontamination agent. As a result of comparing the weight of the finally produced decontamination agent, a mass loss of about 20% occurred during the production and drying process. The final formulation was in the form of pellets or tablets.

[Comparative Examples 1 to 5] Preparation of radioactive cesium decontamination agent (depth outside)

Decontamination agents were prepared in the same manner as in Example 1, respectively, and the decontamination agents of Comparative Examples 1 to 5 were prepared using the composition ratios shown in Table 4 below.

type	Sodium hydrogen carbonate	Citric acid	Zeolite
Example 1	40	20	40
Comparative Example 1	49	2	49
Comparative Example 2	48	5	48
Comparative Example 3	44	11	44
Comparative Example 4	6	31	63
Comparative Example 5	25	25	50

Analysis of dispersion and decontamination in water

In order to remove cesium in water, a decontamination agent (Examples 1 and Comparative Examples 1 to 5) prepared by different mixing ratios was placed in a water tank, and sedimentation and dispersion tendencies were observed, and among them, the dispersion tendency was most excellent. Turbidity and cesium concentrations by location and depth of decontamination agent of 1 were measured and illustrated.

7A to 7F are graphs showing changes in turbidity concentration over time by the decontamination agent of Example 1; Figure 7a is a graph showing the turbidity concentration change after 1 minute by the decontamination agent of Example 1, Figure 7b is a graph showing the turbidity concentration change after 3 minutes by the decontamination agent of Example 1, Figure 7c is an implementation Example 1 is a graph showing the turbidity concentration change after 10 minutes by the decontamination agent, Figure 7d is a graph showing the turbidity concentration change after 60 minutes by the decontamination agent of Example 1, Figure 7d is the decontamination of Example 1 It is a graph showing the change in turbidity concentration after 120 minutes by the agent, and FIG. 7F is a graph showing the change in turbidity concentration after 1440 minutes by the decontamination agent of Example 1.

7A to 7F, unlike the powder type decontamination agent, where the sedimentation occurred only vertically without dispersion in the horizontal direction, it was confirmed that the sedimentation occurred after the dispersion of the horizontal dispersion occurred largely and spread from about 60 cm below the water surface. Could. The sedimentation of the whole sedimentation occurs rapidly, similar to the powder type decontamination agent, but it appears that the dispersion occurs much wider than the powdery form in the horizontal direction. It was confirmed that the zeolite particles were suspended even at about 60 minutes after the decontamination agent was added.

8A to 8F are graphs showing changes in cesium concentration over time by the decontamination agent of Example 1; Figure 8a is a graph showing the change in cesium concentration after 1 minute by the decontamination agent of Example 1, Figure 8b is a graph showing the change in cesium concentration after 3 minutes by the decontamination agent of Example 1, Figure 8c is carried out Graph showing the change in cesium concentration after 10 minutes by the decontamination agent of Example 1, Figure 8d is a graph showing the change in cesium concentration after 60 minutes by the decontamination agent of Example 1, Figure 8d is the decontamination of Example 1 It is a graph showing the change in cesium concentration after 120 minutes by the agent, and FIG. 8F is a graph showing the change in cesium concentration after 1440 minutes by the decontamination agent of Example 1.

Referring to Figures 8a to 8f, in the case of cesium concentration in water, it can be confirmed that cesium is removed at a deeper depth than the decontamination agent in powder form, and the removal rate of cesium at the deepest depth after about 1 day is about 80%. Appeared to reach. However, relatively, cesium near the surface of the water showed properties that are hardly removed.

The decontamination agents of Comparative Examples 1 to 5, which were prepared by different mixing ratios with the decontamination agents of Example 1, did not cause retardation of sedimentation rate or dispersion in the horizontal direction. In some decontamination agents, dispersion did not occur at all until it reached the bottom of the tank, and in some decontamination agents, dispersion occurred, but the degree was weak.

As described above, after selecting the zeolite powder as the basic material for the cesium decontamination agent in water, chemicals such as sodium hydrogen carbonate and citric acid were added to improve the existing powder type decontamination agent. As a result of measuring the turbidity and cesium concentration by adding the improved decontamination agent to the water tank, it was found that sedimentation, horizontal dispersion, and spatial removal rate were different from those of the conventional zeolite powder. In the case of the zeolite decontamination agent added in powder form, the precipitation in the vertical direction was superior to the dispersion in the horizontal direction, and the concentration of cesium in water was also decreased only in the vertical direction in which the zeolite precipitated. Precipitation was predominant, so it was found that the powder reached the bottom 3 minutes after the decontamination agent was added, and was distributed parallel to the bottom after 10 minutes.

Among the improved decontamination agents of Example 1 and Comparative Example, the other types of decontamination agents, except for Example 1, did not cause retardation of sedimentation rate or dispersion in the horizontal direction. The decontamination agent of Example 1 settled similarly to the powder decontamination agent in the vertical direction, but the dispersion was much wider than that of the powder decontamination agent after being reprecipitated after being dispersed in the horizontal direction at about 60 cm below the water surface. Appeared to be. Although the concentration of cesium in water was slightly different depending on the measurement location, in contrast to the powdered decontamination agent, where the decrease in cesium concentration occurred near the water surface, the decontamination agent of Example 1 retained cesium near the water surface over time. Appeared to be.

In consideration of the sedimentation, dispersion, and cesium removal characteristics for each type of decontamination agent, it is considered to be appropriate to apply the decontamination agent of Example 1 among the improved decontamination agents by varying the mixing ratio for the purpose of removing cesium distributed in the water-based deep portion. .

Based on the experimental results, as a radioactive cesium decontamination agent, zeolite 30-40% by weight; Sodium hydrogen carbonate 30-40% by weight; And 20-40% by weight of citric acid was determined as a customized decontamination agent for deep-water radioactive cesium decontamination.

[Example 2] Preparation of radioactive cesium decontamination agent (for layering)

The foamed decontamination agent was mixed with the content of the main additives sodium hydrogen carbonate, citric acid and zeolite in an amount as shown in Table 5, and ethanol (C2H5OH) was used to mold them. The amount of zeolite injected on the basis of 1 ton was applied equally to 50 g as the result of the previous preliminary experiment. Ethanol for mixing and molding the zeolite and other ancillary materials was injected at about 20% of the total decontamination agent mass, and put into a production mold to dry for 2 days or more in an oven set to 40°C to prepare a decontamination agent. As a result of comparing the weight of the finally produced decontamination agent, a mass loss of about 20% occurred during the production and drying process. The final formulation was in the form of pellets or tablets.

[Comparative Examples 6 to 10] Preparation of radioactive cesium decontamination agent (outside the middle layer)

Decontamination agents were prepared in the same manner as in Example 2, respectively, and the decontamination agents of Comparative Examples 6 to 10 were prepared at the composition ratios shown in Table 5 below.

type	Sodium hydrogen carbonate	Citric acid	Zeolite
Example 2	29	14	57
Comparative Example 6	49	2	49
Comparative Example 7	48	5	48
Comparative Example 8	44	11	44
Comparative Example 9	6	31	63
Comparative Example 10	25	25	50

Dispersion and decontamination trend analysis in water

In order to remove cesium in water, a decontamination agent (Example 2, Comparative Examples 6 to 10) prepared by different mixing ratios was placed in a water tank, and sedimentation and dispersion tendencies were observed, and among them, the dispersion tendency was most excellent. Turbidity and cesium concentrations by location and depth of decontamination agent of 2 were measured and plotted.

9A to 9F are graphs showing changes in turbidity concentration over time by the decontamination agent of Example 2; Figure 9a is a graph showing the change in turbidity concentration after 1 minute by the decontamination agent of Example 2, Figure 9b is a graph showing the change in turbidity concentration after 3 minutes by the decontamination agent of Example 2, Figure 9c is an implementation Graph showing the change in turbidity concentration after 10 minutes by the decontamination agent of Example 2, Figure 9d is a graph showing the change in turbidity concentration after 60 minutes by the decontamination agent of Example 2, Figure 9d is the decontamination of Example 2 It is a graph showing the change in turbidity concentration after 120 minutes by the agent, and FIG. 9F is a graph showing the change in turbidity concentration after 1440 minutes by the decontamination agent of Example 2.

9A to 9F, unlike powder-type decontamination agents that only settle vertically without dispersing in the horizontal direction, homemade salts settle vertically and then rise back to the surface at about 30 cm below the surface and then spread downward. It showed the appearance, and it was confirmed that a small amount of decontaminant particles were suspended even after 2 hours, unlike the powdered decontamination agent, which had all settled to the floor before less than 1 hour, causing a delayed sedimentation effect. In addition, it was confirmed that the horizontal dispersion effect of particles also occurred in the process of sedimentation after re-injury to the water surface.

10A to 10F are graphs showing changes in cesium concentration over time by the decontamination agent of Example 2; Figure 10a is a graph showing the change in cesium concentration after 1 minute by the decontamination agent of Example 2, Figure 10b is a graph showing the change in cesium concentration after 3 minutes by the decontamination agent of Example 2, Figure 10c is an implementation Graph showing the change in cesium concentration after 10 minutes by the decontamination agent of Example 2, Figure 10d is a graph showing the change in cesium concentration after 60 minutes by the decontamination agent of Example 2, Figure 10d is the decontamination of Example 2 It is a graph showing the change in cesium concentration after 120 minutes by the agent, and FIG. 10F is a graph showing the change in cesium concentration after 1440 minutes by the decontamination agent of Example 2.

10A to 10F, as in the case where horizontal dispersion occurred largely, the concentration of cesium was rapidly decreased in a wide range, and the removal rate of cesium differed depending on the depth, but was confirmed up to 70%.

The decontamination agents of Comparative Examples 6 to 10, which were prepared by different mixing ratios with the decontamination agents of Example 2, did not cause retardation of sedimentation rate or dispersion in the horizontal direction. In some decontamination agents, dispersion did not occur at all until it reached the bottom of the tank, and in some decontamination agents, dispersion occurred, but the degree was weak.

As described above, after selecting the zeolite powder as the basic material for the cesium decontamination agent in water, chemicals such as sodium hydrogen carbonate and citric acid were added to improve the existing powder type decontamination agent. As a result of measuring the turbidity and cesium concentration by adding the improved decontamination agent to the water tank, it was found that sedimentation, horizontal dispersion, and spatial removal rate were different from those of the conventional zeolite powder. In the case of the zeolite decontamination agent added in powder form, the precipitation in the vertical direction was superior to the dispersion in the horizontal direction, and the concentration of cesium in water was also decreased only in the vertical direction in which the zeolite precipitated. Precipitation was predominant, so it was found that the powder reached the bottom 3 minutes after the decontamination agent was added, and was distributed parallel to the bottom after 10 minutes.

Among the improved decontamination agents of Example 2 and Comparative Example, the other types of decontamination agents, except for Example 2, did not exhibit a delay in sedimentation rate or dispersion in the horizontal direction. The decontamination agent of Example 2 settled similarly to the powdered decontamination agent in the vertical direction, but it was confirmed that the sedimentation was delayed while re-initiating to the water surface around 30 cm below the surface, and dispersion occurred in the horizontal direction in the process. Could. The concentration of cesium in water was slightly different depending on the measurement location, but it was found to decrease rapidly over a wide range, similar to the dispersed area of the particles.

In consideration of the sedimentation, dispersion, and cesium removal characteristics for each type of decontamination agent, it is considered appropriate to apply the decontamination agent of Example 2 among the improved decontamination agents with different compounding ratios for the purpose of removing cesium distributed in the aqueous middle layer. do.

Based on the experimental results, as radioactive cesium decontamination agent, zeolite 40 to 60% by weight; Sodium hydrogen carbonate 20 to 40% by weight; And 10 to 20% by weight of citric acid was determined as a custom decontamination agent for radioactive cesium decontamination in an aqueous medium layer.

[Example 3] Preparation of anti-inflammatory formulation added corn starch (for middle layer)

Corn starch (corn-starch) was further blended in the process of preparing the foamed decontamination agent of Example 3 to enhance the bonding strength. When the corn starch is additionally included in the decontamination agent, the dosage form of the adsorbent can be constantly controlled, and the intensity is also increased, making it easier to control the depth. When corn starch is not added, the form of the decontamination agent is shown in Fig. 11A, and the form of the decontamination agent obtained by adding corn starch is shown in Fig. 11B. Example 3 was made for a middle layer. The composition ratio of Example 3 is shown in Table 6.

[Example 4] Preparation of anti-inflammatory formulation added corn starch (outside the middle layer)

Example 4 is a decontamination agent for an extra-layer use produced by changing the composition ratio in the process of preparing the foamed decontamination agent of Example 3. Table 4 shows the composition ratio of Example 4.

[Comparative Examples 11 to 13] Preparation of anti-inflammatory formulation added corn starch

Comparative Examples 11 to 13 are decontamination agents prepared by changing the composition ratio in the process of manufacturing a foamed decontamination agent. Table 6 shows the composition ratios of Comparative Examples 11 to 13.

type	Zeolite	Sodium hydrogen carbonate	Citric acid	Corn starch
Example 3	4	2	One	One
Example 4	4	4	2	One
Comparative Example 11	4	2	One	0
Comparative Example 12	2	2	One	One
Comparative Example 13	8	4	2	One

Analysis of additional dispersion in water

40L (width 30cm, width 30cm, depth 50cm) of the decontamination agent (Example 3, Example 4, Comparative Examples 11 to 13) prepared by different mixing ratios to remove cesium in water as shown in FIGS. 12 to 17 After filling the water tank with water at a temperature of 20° C. to a depth of 45 cm, an adsorbent was dropped at 5 cm above the water surface to observe the tendency to sedimentation and dispersion. The adsorbent formulation was prepared in a cylindrical shape with a diameter of 3 cm, a height of 1 cm, and a mass of about 10 g, as shown in FIGS. 11A and 11B.

12A to 12D show the dispersion pattern over time for the decontamination agent of Example 3. Figure 12a shows the dispersion pattern after 2 seconds after administration of the anti-inflammatory agent of Example 3. Immediately after dropping the decontamination agent of Example 3, it settled down to 10 cm below the surface of the water and floated again to disperse on the surface for 3 seconds. Figure 12b shows the dispersion pattern after 8 seconds after administration of the anti-inflammatory agent of Example 3. The decontamination agent of Example 3 settles to the bottom of the water tank 8 seconds after administration. Figure 12c shows the dispersion pattern after 20 seconds after administration of the decontamination agent. The anti-inflammatory agent of Example 3, which was strongly dispersed only in the vertical direction, rose to the surface again 20 seconds after administration. Figure 12d shows the dispersion pattern after 40 seconds after administration of the anti-inflammatory agent of Example 3. The decontamination agent of Example 3 continues to disperse, and after 40 seconds, it is completely dispersed throughout the water bath.

13A to 13D show the dispersion pattern over time for the decontamination agent of Example 4. Figure 13a shows the dispersion pattern after 2 seconds after administration of the decontamination agent of Example 4. Immediately after dropping the decontamination agent of Example 4, it sinks to 5 cm below the surface of the water and then rises again, but immediately sinks. Figure 13b shows the dispersion pattern after 5 seconds after administration of the decontamination agent of Example 4. The decontamination agent of Example 4 reaches the bottom of the tank 5 seconds after administration. Figure 13c shows the dispersion pattern after 20 seconds after administration of the decontamination agent of Example 4. The anti-inflammatory agent of Example 4, which was strongly dispersed in the vertical direction and weakly dispersed in the horizontal direction, and exhibited the dispersion behavior in the form of I, rose to the surface again after 30 seconds after administration. Figure 13d shows the dispersion pattern after 40 seconds after administration of the anti-inflammatory agent of Example 4. The decontamination agent of Example 4 continued to disperse, and after 35 seconds, it was completely dispersed throughout the water bath.

14A to 14C show the dispersion pattern over time for the decontamination agent of Comparative Example 11. Figure 14a shows the dispersion pattern after 4 seconds after administration of the decontamination agent. The decontamination agent of Comparative Example 11 reaches the bottom of the tank after 4 seconds immediately after dropping. Figure 14b shows the dispersion pattern after 20 seconds after administration of the decontamination agent of Comparative Example 11. The decontamination agent of Comparative Example 11 is dispersed in the vertical direction as the decontamination agent is released after reaching the bottom of the water tank. Figure 14c shows the dispersion pattern after 60 seconds after administration of the decontamination agent of Comparative Example 11. The particles dispersed in the decontamination agent of Comparative Example 11 and raised near the water surface re-sedimented again, and after 60 seconds have elapsed, the particles are evenly dispersed.

15a to 15c show the dispersion pattern over time for the decontamination agent of Comparative Example 12. Figure 15a shows the dispersion pattern after 2 seconds after administration of the decontamination agent of Comparative Example 12. The decontamination agent of Comparative Example 12 settled to 10 cm below the surface of the water immediately after being dropped, and then re-emerged and dispersed for 1 second on the surface of the water. 15B shows the dispersion pattern after 5 seconds after administration of the decontamination agent of Comparative Example 12. The decontamination agent of Comparative Example 12 settles to the bottom of the water tank 5 seconds after administration. Figure 15c shows the dispersion pattern after 70 seconds after administration of the decontamination agent of Comparative Example 12. The decontamination agent of Comparative Example 12 was dispersed in the vertical direction and completely dispersed after 70 seconds.

16A to 16D show the dispersion pattern over time for the decontamination agent of Comparative Example 13. Figure 16a shows the dispersion pattern after 4 seconds after administration of the decontamination agent. Immediately after dropping the decontamination agent of Comparative Example 13, it settled down to 10 cm below the surface of the water and floated again to disperse on the surface for 3 seconds. Figure 16b shows the dispersion pattern after 8 seconds after administration of the decontamination agent of Comparative Example 13. The decontamination agent of Comparative Example 13 sinks to the bottom of the water tank 8 seconds after administration, and then is dispersed only in the vertical direction. Figure 16c shows the dispersion pattern after 20 seconds after administration of the decontamination agent. The anti-inflammatory agent of Comparative Example 13 floats on the surface again 20 seconds after administration. Figure 16d shows the dispersion pattern after 60 seconds after administration of the decontamination agent of Comparative Example 13. The decontamination agent of Comparative Example 13 continued to disperse, and after 60 seconds, it was completely dispersed throughout the water tank.

The dispersion behaviors of Examples 3 and 4 and Comparative Examples 11 to 13 are evaluated as shown in Table 7 below. Dispersion behavior was evaluated by dividing the tank depth by 45 cm into 3 sections of 15 cm from the top and dividing it into upper, middle, and lower regions, and describing the regions in the order in which the decontamination agents were horizontally dispersed.

	Dispersion behavior	Dispersion rate
Example 3	Top→Middle→Bottom	40 seconds
Example 4	Top→bottom→middle	35 seconds
Comparative Example 11	Top→bottom→middle	60 seconds
Comparative Example 12	Top→Middle→Bottom	70 seconds
Comparative Example 13	Top→Middle→Bottom	60 seconds

The dispersing rate was evaluated by recording the time when the adsorbent was completely spread over the entire water tank and dispersion was completed. As a result of the experiment, considering the dispersion behavior and dispersion speed, it was judged to be optimal to perform as in Example 3 as the decontamination agent for the middle layer and in Example 4 as the decontamination agent for the deep layer.

Additional analysis of dispersion in water according to temperature

Additional experiments were conducted to determine the dispersion performance according to the temperature and the formulation mass of the adsorbent. 17A and 17B show the dispersion pattern of the decontamination agent according to the temperature and the formulation mass of the adsorbent.

Figure 17a has the same blending ratio as in Example 3, showing the appearance of 15 seconds after dropping the decontamination agent prepared in a formulation of 10g to 0 ℃ (left), 20 ℃ (right) in two different temperature tanks . As a result of evaluating the dispersion performance of the decontamination agent at 0℃~3℃, which is a low-temperature environment, the decontamination agent made of 10g stays only at the surface of the water regardless of the mixing ratio, and is dispersed only in the vertical direction without dispersion in the horizontal direction. Significantly slower than the dispersion rate at room temperature.

FIG. 17B shows the appearance of 15 seconds after dropping the decontamination agent produced at 12 g to 0° C. (left) and 20° C. (right) with the same mixing ratio as in Example 4 in two different water tanks. As a result of evaluating the dispersion performance of the decontamination agent at 0° C. to 3° C. in a low temperature environment, the decontamination agent made of 12 g has an increased weight of the decontamination agent formulation, so that when the decontamination agent reaches the bottom in the water, the decontamination agent is dispersed in the low temperature environment. Degradation can be overcome. In other words, the dispersion rate of the decontamination agent is slightly slower than that at 20°C, but the decontamination agent made of the 10 g formulation shows a much better dispersion behavior at the same time compared to the dispersion on the water surface.

The present technology relates to a technology for decontamination of pollutants in water, and in particular, a technology for decontamination agents and decontamination methods capable of efficiently decontaminating radioactive cesium present in water for various water depths.

Claims (24)

1. Decontamination agent for removing radioactive substances contained in contaminated water,

   Zeolite; Sodium hydrogen carbonate; And a decontamination agent for radioactive contaminants comprising citric acid.
2. According to claim 1,

   The decontamination agent is 30 to 60% by weight of zeolite;

   Sodium hydrogen carbonate 20-40% by weight; And

   An anti-inflammatory agent which is 10 to 40% by weight of citric acid.
3. According to claim 1,

   The decontamination agent is 40 to 60% by weight of zeolite; Sodium hydrogen carbonate 20-40% by weight; And

   10 to 20% by weight of citric acid,

   The decontamination agent is to remove the radioactive material contained in the middle layer, the decontamination agent.
4. According to claim 1,

   The decontamination agent is 30 to 40% by weight of zeolite; Sodium hydrogen carbonate 30-40% by weight; And

   20 to 40% by weight of citric acid,

   The decontamination agent is to remove the radioactive material contained in the deep water system, decontamination agent.
5. According to claim 1,

   The decontamination agent further comprises corn starch, decontamination agent.
6. According to claim 2,

   The decontamination agent is 5 to 20% by weight of corn starch, decontamination agent.
7. The method of claim 6,

   The decontamination agent is a decontamination agent, wherein the weight ratio of zeolite, sodium hydrogen carbonate, citric acid and corn starch is 2: 1-2: 0.5-1: 0.25-1.
8. The method of claim 7,

   The decontamination agent is a weight ratio of zeolite, sodium hydrogen carbonate, citric acid and corn starch in a ratio of 2: 1: 0.5: 0.5, and the decontamination agent is for removing radioactive substances contained in the middle layer aqueous system.
9. The method of claim 7,

   The decontamination agent is a weight ratio of zeolite, sodium hydrogen carbonate, citric acid and corn starch in a ratio of 2: 1: 0.5: 0.25, and the decontamination agent is for removing radioactive substances contained in the deep water system.
10. According to claim 1,

    The zeolite is 50 to 60% by weight of heliumite and 40 to 50% by weight of mordenite.
11. According to claim 1,

    The zeolite has a specific surface area of 50 to 70 m ² /g, an average pore volume of 0.1 to 0.15 ml/g, an average pore size of 5 to 15 nm, or a cation exchange capacity of 60 to 120 meq/100 g.
12. According to claim 1,

    The radioactive material is selected from the group consisting of iodine, cesium, cerium, rhodium, cobalt, strontium, radium, uranium, and plutonium, decontamination agents.
13. To remove radioactive substances contained in contaminated water,

    Zeolite; Sodium hydrogen carbonate; And mixing citric acid to produce a decontamination agent for radioactive contaminants.
14. The method of claim 13,

    The decontamination agent is 30 to 60% by weight of zeolite;

    Sodium hydrogen carbonate 20-40% by weight; And

    10 to 40% by weight of citric acid, a method for producing a decontamination agent for radioactive contaminants.
15. The method of claim 13,

    The decontamination agent is 40 to 60% by weight of zeolite; Sodium hydrogen carbonate 20-40% by weight; And

    10 to 20% by weight of citric acid,

    The decontamination agent is to remove the radioactive material contained in the middle layer, a method of manufacturing a decontamination agent for radioactive contaminants.
16. The method of claim 13,

    The decontamination agent is 30 to 40% by weight of zeolite; Sodium hydrogen carbonate 30-40% by weight; And

    20 to 40% by weight of citric acid,

    The decontamination agent is to remove the radioactive material contained in the deep water system, a method of manufacturing a decontamination agent for radioactive contaminants.
17. The method of claim 13,

    The decontamination agent further comprises corn starch, a method for preparing a decontamination agent for radioactive contaminants.
18. The method of claim 14,

    The decontamination agent is 5 to 20% by weight of corn starch, a method for producing a decontamination agent for radioactive contaminants.
19. The method of claim 18,

    The decontamination agent is a method of preparing a decontamination agent for radioactive contaminants in a weight ratio of zeolite, sodium hydrogen carbonate, citric acid and corn starch in a ratio of 2: 1 to 2: 0.5 to 1: 0.25 to 1.
20. The method of claim 19,

    The decontamination agent is a weight ratio of zeolite, sodium hydrogen carbonate, citric acid and corn starch in a weight ratio of 2: 1: 0.5: 0.5, and the decontamination agent is for removing radioactive substances contained in the middle layer aqueous system. Method of preparing decontamination agents.
21. The method of claim 19,

    The decontamination agent is a weight ratio of zeolite, sodium hydrogen carbonate, citric acid and corn starch in a weight ratio of 2: 1: 0.5: 0.25, and the decontamination agent is for removing radioactive substances contained in the deep water system. Method of preparing decontamination agents.
22. The method of claim 13,

    The zeolite is 50 to 60% by weight of heliumite and 40 to 50% by weight of mordenite, a method for preparing a decontamination agent for radioactive contaminants.
23. The method of claim 13,

    The zeolite has a specific surface area of 50 to 70 m ² /g, an average pore volume of 0.1 to 0.15 ml/g, an average pore size of 5 to 15 nm, or a cation exchange capacity of 60 to 120 meq/100 g.
24. The method of claim 13,

    The radioactive material is selected from the group consisting of iodine, cesium, cerium, rhodium, cobalt, strontium, radium, uranium, and plutonium, decontamination agents.

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