Iodine sustained-release sterilizer and method for sterilizing water systems

Abstract

To provide an iodine sustained-releasing sterilizer for releasing or sustained-releasing iodine, wherein the sterilizer can be disposed of safely after use and the sterilizer is easy to handle.SOLUTION: An iodine sustained-releasing sterilizer 1 comprises a solution 12 comprising water, iodine and iodide object, the solution being covered with a film or a container 10 having gas permeability.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an iodine sustained-release sterilizing device that releases or sustainedly releases iodine, and a method for sterilizing a water system using the same. [Background technology]

[0002] Iodine has extremely high bactericidal power and relatively low effects on the human body, so it is widely used for sterilization purposes as Lugol's solution and povidone-iodine. Taking advantage of the high adsorption capacity of iodine, it is also used as a sustained-release sterilizer, which sterilizes objects by adsorbing iodine onto polymer compounds and then slowly releasing it.

[0003] Patent Document 1 describes an iodine gas release device in which a polymer compound having iodine adsorbed thereon is made to coexist with water and / or an organic solvent, and the polymer compound is covered with a gas-permeable non-porous film.

[0004] Iodine gas release devices such as those described in Patent Document 1 require the disposal of the polymer compound to which iodine has been adsorbed after use. In order to safely dispose of these devices, it is desirable to reduce the iodine adsorbed to the polymer compound with a reducing agent such as sodium thiosulfate before disposal. However, iodine adsorbed to the polymer compound cannot be reduced immediately, and disposal can require time and effort.

[0005] Furthermore, Patent Document 1 describes that the amount of iodine released changes depending on the coexisting water and / or organic solvent, but there are problems in that it is difficult to respond to changes in the conditions of the water system supplied outside the iodine gas release device, and that iodine continues to be released from the time of production to the time of use, requiring careful handling.

[0006] For the reasons mentioned above, it is difficult to say that iodine gas release devices in which iodine is adsorbed onto a polymer compound are easy to handle from use to disposal, and there is a demand for ease of handling. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-152404 Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide a sterilizing device that releases or sustainedly releases iodine, which can be safely disposed of after use and is easy to handle, and a method for sterilizing a water system using the same. [Means for solving the problem]

[0009] The present invention relates to a method for producing an iodine-containing solution containing water, iodine, and iodine- potassium A solution containing the compound is covered with a gas-permeable film or container. The total iodine content of the solution containing water, iodine, and potassium iodide is 5% by mass or more, the entire surface or a part of the gas-permeable film or container is covered with a gas-impermeable film or container, and the gas permeability of the gas-impermeable film or container is 3500 cm or more in terms of oxygen permeability. 3 / m 2 d atm or less, and the gas permeability of the gas-permeable film or container is 3500 cm as oxygen permeability. 3 / m 2 d ATM or higher It is an iodine-releasing sterilizing device.

[0012] In the iodine sustained-release sterilizing device, it is preferable that the exposed area of ​​the gas-permeable film or container can be increased or decreased by increasing or decreasing the covered area of ​​the gas-impermeable film or container.

[0014] In the iodine sustained-release sterilizer, the material of the gas-impermeable film or container is preferably at least one of polyvinyl chloride, high-density polyethylene, polyethylene terephthalate, polyvinylidene chloride, and polyvinyl alcohol.

[0016] In the iodine sustained-release sterilizer, the material of the gas-permeable film or container is preferably at least one of low-density polyethylene, polypropylene, and polystyrene.

[0017] The iodine sustained-release sterilizer is preferably an iodine sustained-release sterilizer for sterilizing a water system.

[0018] In the iodine sustained-release sterilizer, it is preferable to increase or decrease the exposed area of ​​the gas-permeable film or container based on at least one of the water residence time and contamination status of the water system to be sterilized.

[0019] In the iodine sustained-release sterilizer, the aqueous system is preferably an open aqueous system.

[0020] The present invention is a method for sterilizing a water system, which comprises placing the iodine sustained-release sterilizing device in the water system. [Effects of the Invention]

[0021] The present invention provides a sterilizing device that releases or sustainedly releases iodine, which can be safely disposed of after use and is easy to handle, and a method for sterilizing a water system using the same. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram showing an example of an iodine sustained-release sterilizer according to an embodiment of the present invention. FIG. [Figure 2] FIG. 10 is a schematic diagram showing another example of an iodine sustained-release sterilizing device according to an embodiment of the present invention. [Figure 3] 1 is a photograph showing the iodine sustained-release sterilizing device used in Example 2 (left: exposed area 1 cm 2 , center: exposed area 2 cm 2 , right: no film). DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present invention. The embodiment is an example of implementing the present invention, and the present invention is not limited to the embodiment.

[0024] An example of an iodine sustained-release sterilizing device according to an embodiment of the present invention is outlined in Figures 1 and 2, and its configuration will be described. The iodine sustained-release sterilizing device according to this embodiment is a sterilizing device that releases or sustained-releases iodine.

[0025] The iodine sustained-release sterilizing device 1 shown in FIG. 1 is a sterilizing device in which a solution 12 containing water, iodine, and iodide is covered with a gas-permeable film or container 10.

[0026] The iodine sustained-release sterilizing device 3 shown in Figure 2 is a sterilizing device in which a solution 12 containing water, iodine, and iodide is covered with a gas-permeable film or container 10, and the entire surface or a part of the gas-permeable film or container 10 is covered with a gas-impermeable film or container 14.

[0027] As a result of intensive research by the present inventors, it has become clear that by covering a solution containing water, iodine, and iodide with a gas-permeable film or container, the iodine can be easily released while the labor required for disposal is significantly reduced. In the iodine sustained-release sterilizing device according to this embodiment, the solution containing water, iodine, and iodide can be, for example, a liquid similar to the widely used Lugol's solution or povidone-iodine, and can be disposed of directly in the sewer, etc. To further safely dispose of such a solution, it can be reduced with a reducing agent such as sodium thiosulfate to convert it into more harmless iodide ions, making disposal extremely easy.

[0028] The "iodine" contained in the solution containing water, iodine, and iodide may be in any form as long as it has oxidizing power, and may be any one or combination of molecular iodine, polyiodide, iodic acid, hypoiodous acid, periodic acid, iodine coordinated to an organic solvent such as polyvinylpyrrolidone or cyclodextrin. Methods for obtaining any of these forms of iodine include dissolving solid iodine in a nonpolar solvent such as benzene or carbon tetrachloride or in an alcohol, dissolving it using an alkali and water, or dissolving it using iodide and water. Total iodine may also be obtained by adding an acid or an oxidizing agent to a solution containing at least one of iodide and iodide ions. Iodine coordinated to an organic solvent such as polyvinylpyrrolidone or cyclodextrin may also be obtained using povidone-iodine in which iodine is coordinated to polyvinylpyrrolidone, iodine-inclusion cyclodextrin in which iodine is included in cyclodextrin, or iodophor in which iodine is supported on an organic polymer or surfactant. In this embodiment, considering the wastewater quality and other factors, it is preferable to dissolve solid iodine in an iodide salt and water without using organic substances. Iodide refers to an iodine compound with an oxidation state of 1, such as potassium iodide, sodium iodide, hydrogen iodide, or silver iodide. Naturally, these iodides dissociate into iodide ions when dissolved in water. Examples of iodide salts include inorganic iodide salts such as sodium iodide and potassium iodide, with potassium iodide being preferred.

[0029] The solution containing water, iodine, and iodide preferably contains 2% by mass or more of total iodine, more preferably 5% by mass or more, from the viewpoint of good stability, etc. The good stability of the solution allows the iodine sustained-release sterilizing device to be used for a long period of time.

[0030] In this specification, the oxidizing power of iodine is expressed as total iodine measured by the DPD method. In this specification, "total iodine" refers to the concentration determined by the spectrophotometric method using N,N-diethyl-p-phenylenediammonium sulfate (DPD) as described in "JIS K 0120:2013, Section 33. Residual Chlorine." For example, 2.5 mL of 0.2 mol / L potassium dihydrogen phosphate solution is placed in a 50 mL colorimetric tube, to which 0.5 g of DPD diluted powder (1.0 g of N,N-diethyl-p-phenylenediammonium sulfate ground and mixed with 24 g of sodium sulfate) is added, 0.5 g of potassium iodide is added, and an appropriate amount of sample is added. Water is added up to the mark, dissolved, and allowed to stand for approximately 3 minutes. The resulting pink to pinkish-red color is quantified by measuring the absorbance at a wavelength of approximately 510 nm (or 555 nm). This test method involves quantifying all forms of iodine that can have oxidizing power (e.g., I2, IO3). - ,IO - , HI) are collectively measured as "total chlorine," so they are converted to "total iodine." Specifically, the conversion is based on the "molecular weight of chlorine" and the "molecular weight of iodine." In other words, "total chlorine" x (126.9 / 35.45) ≒ "total chlorine" x 3.58 = "total iodine."

[0031] In this embodiment, the gas-permeable film or container may be a film that is substantially impermeable to a solution but is permeable to a gas such as iodine gas, or a container that is substantially impermeable to a solution but is permeable to a gas such as iodine gas, as long as it is not significantly degraded by iodine. Examples of materials for such films or containers include low-density polyethylene, polypropylene, and polystyrene. Polyethylene is synthesized by a high-pressure method or a low-pressure method, with polyethylene synthesized by the high-pressure method being called low-density polyethylene (LDPE) and polyethylene synthesized by the low-pressure method being called high-density polyethylene (HDPE). The density of LDPE (low-density polyethylene) is 0.910 to 0.925 g / cm. 3 The density of HDPE (high density polyethylene) is 0.910-0.965g / cm 3 The specific gravity is approximately 0.94 to 0.97.

[0032] An index of substantially impermeable to a solution is, for example, a water vapor permeability of 600 g / m (measured in accordance with JIS K 7129-B, at 40°C and 90% RH, converted to a thickness of 25 μm). 2 ·d or less is sufficient, 100g / m 2 ·d or less is preferable, and 50 g / m 2 As an index of gas permeability such as iodine gas, for example, oxygen permeability (measured in accordance with JIS K 7126-B, under conditions of 25°C and 65% RH, converted into a value of 25 μm thickness) is 3500 cm 3 / m 2 d atm or higher is sufficient, and 5000 cm 3 / m 2 d atm or higher, and 7000 cm 3 / m 2 As the gas-permeable film or container, a single material may be used so as to satisfy such water vapor permeability and oxygen permeability, or a combination of multiple materials may be used so as to satisfy such water vapor permeability and oxygen permeability.

[0033] The size of the iodine sustained-release sterilizer is not particularly limited, but from the viewpoint of the amount of iodine released, a volume of 0.1 m is recommended. 3 Preferably, it is less than 0.05m 3 It is more preferable that the length of one side is not more than 1 / 2. The shape of the iodine sustained-release sterilizing device is not particularly limited, and may be any of a prismatic shape such as a cube or a rectangular parallelepiped, a polyhedron such as a triangular pyramid, a sphere, a cylinder, a cone, etc., but is preferably any of a cube, a rectangular parallelepiped, or a cylinder from the viewpoint of self-supporting ability and workability of the sterilizing device.

[0034] The gas-impermeable film or container may be a film that is substantially impermeable to solutions and gases such as iodine gas, or a container that is substantially impermeable to solutions and gases such as iodine gas. Examples of materials for such films or containers include polyvinyl chloride, high-density polyethylene, polyethylene terephthalate, polyvinylidene chloride, and polyvinyl alcohol. An index of substantially impermeable to solutions is, for example, a water vapor permeability of 600 g / m2 (measured in accordance with JIS K 7129-B, at 40°C and 90% RH, converted to a thickness of 25 μm). 2 ·d or less is sufficient, 100g / m 2 ·d or less is preferable, and 50 g / m 2 As an index of substantially preventing the permeation of gases such as iodine gas, for example, the gas permeability is, for example, oxygen permeability (measured in accordance with JIS K 7126-B, under conditions of 25°C and 65% RH, converted into a value of 25 μm thickness) of 3500 cm 3 / m 2 d atm or less is sufficient, and 3000 cm 3 / m 2 d atm or less, and 1000 cm 3 / m 2 As the gas-impermeable film or container, a single material may be used so as to satisfy the water vapor permeability and oxygen permeability requirements, or a combination of multiple materials may be used so as to satisfy the water vapor permeability and oxygen permeability requirements.

[0035] The gas-impermeable film or container covers the entire or part of the gas-permeable film or container, and by adjusting the exposed area of ​​the gas-permeable film or container, the amount of iodine released from the iodine sustained-release sterilizer can be freely adjusted. The exposed area of ​​the gas-permeable film or container can be increased or decreased by increasing or decreasing the covered area of ​​the gas-permeable film or container. The exposed area may be determined during the manufacture of the sterilizer, or the gas-permeable film may be peelably attached so that the exposed area can be adjusted after manufacture and immediately before use, or a portion of the gas-permeable film or container may be openable and closable. Because iodine has a unique sublimation property and becomes colored, it is preferable that the exposed area not be present until immediately before use from the standpoint of ease of handling, etc. By increasing or decreasing the covered area of ​​the gas-permeable film or container, the amount of iodine released from the iodine sustained-release sterilizer can be freely increased or decreased.

[0036] When the iodine slow-release sterilizing device does not have a gas-impermeable film or container, the amount of iodine released from the iodine slow-release sterilizing device may be adjusted by adjusting the gas permeability of the gas-permeable film or container.

[0037] By placing the iodine sustained-release sterilizer in a water system, it continuously releases a predetermined amount of iodine into the water system, thereby suppressing contamination of the water system. Because iodine has extremely high sterilizing power, a high sterilizing effect can be achieved with the amount of iodine released from a gas-permeable film or container.

[0038] By increasing or decreasing the covering area of ​​the gas-impermeable film or container and increasing or decreasing the exposed area of ​​the gas-permeable film or container based on the water residence time and contamination level of the water system, it is possible to effectively achieve a sterilization effect for water with any water residence time and contamination risk. For example, in a water system with a short water residence time, the covering area of ​​the gas-permeable film or container is increased and the exposed area of ​​the gas-permeable film or container is reduced, and in a water system with a long water residence time, the covering area of ​​the gas-permeable film or container is reduced and the exposed area of ​​the gas-permeable film or container is increased, thereby achieving a sterilization effect while suppressing the impact of released iodine on peripheral equipment. Furthermore, in a water system with severe contamination of the inflowing water, the covering area of ​​the gas-permeable film or container is reduced and the exposed area of ​​the gas-permeable film or container is increased, thereby effectively suppressing contamination of the water system.

[0039] The exposed area depending on the water residence time may be determined, for example, according to the following (Equation 1). 0<Exposed area (m 2 )<100 / water residence time (min) (Equation 1)

[0040] If the exposed area is 0, the bactericidal effect will not be achieved and contamination of the water system will not be suppressed. If the exposed area is greater than (Equation 1), contamination of the water system can be suppressed, but there is a possibility that it will have a negative impact on surrounding facilities and equipment.

[0041] The water system in which the iodine sustained-release sterilizing device is installed may be either a closed water system or an open water system, but considering the impact of released iodine on surrounding facilities and equipment, an open water system is preferable.

[0042] In this specification, a sealed water system refers to a water system that is substantially completely sealed and does not involve evaporation, such as a sealed circulating cooling water system, etc. An open water system refers to a water system in which water is constantly replaced, such as by small amounts due to evaporation or intentionally draining at a low flow rate, such as landscaped water areas such as fountains in facilities, circulating water systems such as pools and bathtubs, open cooling water systems, piping in water treatment systems, and water systems above drain pans in air conditioning equipment, etc.

[0043] The iodine sustained-release sterilizing device according to this embodiment can be suitably used as a sterilizing device for drain pans of air conditioners and the like. Drain pans, which are installed to collect water generated by condensation in air conditioners and the like, accumulate water generated by condensation in the air conditioners. Condensed water contains bacteria mixed in from the air, forming a biofilm called slime on the drain pan. While the condensed water is designed to be discharged outside the system through piping installed in the drain pan, significant biofilm formation can cause piping blockage. As the piping blockage progresses, the drain water cannot be discharged and water leaks from the drain pan. Water leakage from the drain pan not only deteriorates the appearance but also poses hygienic problems. Therefore, a sterilizing device capable of sterilizing water on the drain pan is needed, and the iodine sustained-release sterilizing device according to this embodiment can be suitably used.

[0044] <Method of disinfecting water systems using an iodine-releasing disinfectant> By placing the iodine sustained-release sterilizing device in a water system such as an open water system, the water system can be kept hygienic by the iodine released or sustained-released from the sterilizing device.

[0045] Furthermore, by placing an iodine sustained-release sterilizer on the drain pan of an air conditioner or the like, contamination on the drain pan can be effectively suppressed. [Example]

[0046] EXAMPLES The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0047] Example 1 Preparation of a solution containing water, iodine, and iodide A solution containing water, iodine, and iodide was prepared by mixing iodine, potassium iodide, and water according to the composition (mass%) shown in Table 1. The total iodine content (mass%) of the prepared solution was as shown in Table 1. The total chlorine concentration was measured using a HACH DR / 3900 multi-parameter water quality analyzer and converted to the total iodine concentration (total iodine amount).

[0048] Specifically, potassium iodide was dissolved in water while stirring, and when a substantially uniform solution was obtained, iodine was added and the mixture was stirred for about 30 minutes to prepare substantially uniform solutions (1) to (7).

[0049] (Storage stability of solutions containing water, iodine and iodide) The prepared solutions (1) to (7) were filled into glass bottles and stored at 25°C and 50°C for 90 days. The total iodine content was measured at the start of storage and after 90 days of storage, and the total iodine retention rate (%) was measured to evaluate storage stability.

[0050] [Table 1]

[0051] The total iodine content was measured after 90 days of storage at 25°C and 50°C, and the total iodine retention rate (%) was as follows: Solution (1): 25℃→98% 50℃→78% Solution (2): 25℃→100% 50℃→82% Solution (3): 25℃→92% 50℃→90% Solution (4): 25℃→100% 50℃→100% Solution (5): 25℃→97% 50℃→95% Solution (6): 25℃→100% 50℃→100% Solution (7): 25℃→100% 50℃→99%

[0052] All solutions are extremely stable, but it is clear that solutions with a total iodine content of 2% by mass or more have high stability at high temperatures, and that solutions with a total iodine content of 5% by mass or more have even higher stability at high temperatures.

[0053] <Example 2> (Disinfectant for water systems) The solution (5) prepared in Example 1 was used to prepare a container that is not permeable to water but is permeable to gas (internal volume: 6 mL, material: low-density polyethylene, water vapor permeability (value measured in accordance with JIS K 7129-B, under conditions of 40°C and 90% RH, equivalent value for a thickness of 25 μm): 20 g / m 2 d, oxygen permeability (measured in accordance with JIS K 7126-B, at 25°C and 65% RH, converted to a thickness of 25 μm): 7900 cm 3 / m 2 6 mL of the solution was filled into a container (2.5 d atm) and sealed with a lid as shown in Figure 2. The container was then covered with a film (material: polyvinyl chloride, water vapor permeability (same as above): 5 g / m) that is impermeable to water and gas. 2 ·d, oxygen permeability (same as above): 200cm 3 / m 2 The exposed area of ​​the container was adjusted by covering it with a film (·d·atm). 13 mL of pure water was placed in a 20 mL glass beaker, and the sterilizer with the film-covered container was placed in it. After leaving it at 25°C for a specified period (24 hours) after placement, the total amount of iodine in the pure water in the beaker was measured, and the amount of iodine released from the sterilizer was also measured. The results are shown in Table 2.

[0054] [Table 2]

[0055] As is clear from Table 2, the total amount of iodine in pure water increased by increasing the exposed area of ​​the gas-permeable container. By increasing or decreasing the covering area of ​​the non-gas-permeable film or container and increasing or decreasing the exposed area of ​​the gas-permeable film or container, the amount of iodine released from the iodine sustained-release sterilizing device could be freely adjusted.

[0056] Example 3 (Bactericidal effect of iodine-releasing disinfectant in water systems) The solution (5) prepared in Example 1 was used to prepare a container that is not permeable to water but is permeable to gas (internal volume: 6 mL, material: low-density polyethylene, water vapor permeability (value measured in accordance with JIS K 7129-B, under conditions of 40°C and 90% RH, equivalent value for a thickness of 25 μm): 20 g / m 2 d, Oxygen permeability (measured in accordance with JIS K 7126-B, at 25°C and 65% RH, converted to a thickness of 25 μm): 7900 cm 3 / m 2 6 mL of the solution was filled into a container (2.5 d atm) and sealed with a lid as shown in Figure 2. The container was then covered with a film (material: polyvinyl chloride, water vapor permeability (same as above): 5 g / m) that is impermeable to water and gas. 2 ·d, oxygen permeability (same as above): 200cm 3 / m 2 d atm), and the exposed area of ​​the container is 8 cm 2 100 mL of dechlorinated Sagamihara well water (bacterial count: 2 × 10) was placed in a 500 mL glass beaker. 3 ) was placed in the glass beaker and heated in a water bath at 35°C for one week. The amount of water lost due to evaporation was replenished daily with dechlorinated Sagamihara well water. The water retention time was 68 hours. After one week, the number of bacteria in the dechlorinated Sagamihara well water in the glass beaker was measured. The number of bacteria was measured using a Sheet Check R2A (manufactured by NIPRO). The results are shown in Table 3.

[0057] [Table 3]

[0058] Place the container in a glass beaker with an exposed area of ​​8cm 2 When the iodine-release disinfectant adjusted to 0.05% was placed in the glass beaker, the number of bacteria decreased to 2 (CFU / mL), and when the iodine-release disinfectant was not placed in the glass beaker, the number of bacteria decreased to 10 4(CFU / mL) or more. Water systems could be sterilized using an iodine-releasing sterilizer in which the exposed surface of a gas-permeable container was adjusted with a gas-impermeable film.

[0059] In this way, an iodine sustained-release sterilizing device that can be safely disposed of after use and is easy to handle, and that releases or sustains the release of iodine, was obtained. [Explanation of symbols]

[0060] 1. Iodine slow-release sterilizing device, 10. Gas-permeable film or container, 12. Solution, 14. Non-gas-permeable film or container.

Claims

1. a solution containing water, iodine, and potassium iodide, the solution being covered with a gas-permeable film or container; the total iodine content of the solution containing water, iodine, and potassium iodide is 5% by mass or more; the entire surface or a part of the gas-permeable film or container is covered with a gas-impermeable film or container, the gas permeability of the gas-impermeable film or container is less than 3500 cm 3 / m 2 ·d·atm in terms of oxygen permeability; An iodine sustained-release sterilizer characterized in that the gas permeability of the gas-permeable film or container is 3500 cm 3 / m 2 ·d·atm or more in terms of oxygen permeability.

2. The iodine sustained-release sterilizer according to claim 1, An iodine sustained-release sterilizer characterized in that the exposed area of ​​the gas-permeable film or container can be increased or decreased by increasing or decreasing the covering area of ​​the gas-impermeable film or container.

3. The iodine sustained-release sterilizer according to claim 1 or 2, The gas-impermeable film or container is made of at least one of polyvinyl chloride, high-density polyethylene, polyethylene terephthalate, polyvinylidene chloride, and polyvinyl alcohol.

4. The iodine sustained-release sterilizer according to any one of claims 1 to 3, The gas-permeable film or container is made of at least one of low-density polyethylene, polypropylene, and polystyrene.

5. The iodine sustained-release sterilizer according to any one of claims 1 to 4, An iodine sustained-release sterilizer characterized in that the exposed area of ​​the gas-permeable film or container is increased or decreased based on at least one of the water residence time and contamination status of the water system to be sterilized.

6. A method for sterilizing a water system, comprising placing the iodine sustained-release sterilizing device according to any one of claims 1 to 5 in the water system.

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