JP2023135597A - Plasma functional liquid production device and method and plant cultivation plant - Google Patents

Abstract

To provide a plasma functional liquid production device and a method, capable of achieving preferable washing effects and sterilization effects even when a plasma gas is introduced into liquid by bubbling, and a plant cultivation plant.SOLUTION: A plasma functional liquid production device 10 comprises: a plasma head 20 for generating a plasma gas including active species from a plasma generation gas; a plasma gas discharge part 30 for discharging the plasma gas in a bubble state; and a plasma function liquid generation tank 41 for storing a solvent S. The device further comprises: a plasma functional liquid generation part 40 for introducing the plasma gas in the bubble state to the solvent S for generating plasma functional liquid L, where oxygen density of the plasma generation gas is 90% or greater.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apparatus and method for producing a plasma functional liquid, and a plant cultivation plant.

BACKGROUND ART In recent years, various technologies for cleaning, sterilization (sterilization), etc. using plasma have been researched. In particular, consideration is being given to introducing plasma-treated gas (plasma gas) into a liquid (solvent) and using active species such as ozone, ions, or radicals generated during plasma treatment to clean or sterilize the liquid. has been done.

Patent Document 1 discloses that ozone, radicals, and the like generated by plasma are introduced into a liquid to be treated by bubbling to decompose organic substances and the like present in the liquid.

Japanese Patent Application Publication No. 2008-178870

By the way, methods for bubbling plasma gas include the Venturi method, which temporarily constricts the liquid flow path and generates fine bubbles due to pressure changes, and the Venturi method, which disperses gas into the liquid flow from fine bubbles and creates fine pores. A micropore method is known in which the bubbles generated in the process are separated by the shear force of the liquid flow.

However, ozone and radicals generated by plasma tend to lose their activity due to pressure changes and shear heat, and depending on the type of plasma gas, there is a risk that sufficient cleaning and sterilization effects may not be obtained. Ta.

Therefore, even when plasma gas is introduced into a liquid by bubbling, a technical problem arises that must be solved in order to achieve good cleaning and sterilization effects, and the present invention solves this problem. The purpose is to

As a result of intensive research in view of the above-mentioned situation, the present inventor found that good cleaning and sterilization effects can be obtained by introducing plasma gas derived from oxygen gas at a predetermined concentration into a solvent by bubbling, The present invention has now been completed.

In order to achieve the above object, a plasma functional liquid manufacturing apparatus according to the present invention includes a plasma gas generation section that generates a plasma gas containing active species from a plasma generation gas, and a plasma gas discharge unit that emits the plasma gas in the form of bubbles. and a plasma functional liquid generation section that includes a plasma functional liquid generation tank that stores a solvent and generates a plasma functional liquid by introducing the plasma gas in a bubble state into the solvent, The concentration was set to be 90% or more.

Further, the method for producing a plasma functional liquid according to the present invention includes a plasma gas generation section that generates a plasma gas containing active species from a plasma generation gas, a plasma gas discharge section that discharges the plasma gas in the form of bubbles, and a plasma gas discharge section that stores a solvent. A plasma functional liquid manufacturing apparatus using a plasma functional liquid manufacturing apparatus, comprising: a plasma functional liquid production tank that generates a plasma functional liquid; and a plasma functional liquid generation unit that generates a plasma functional liquid by introducing the plasma gas in a bubble state into the solvent. In the manufacturing method, the oxygen concentration of the plasma generating gas is 90% or more.

In the present invention, a plasma gas containing active species with excellent cleaning and sterilization effects is generated from a plasma-generated gas with an oxygen concentration of 90% or more, and this plasma gas passes through a plasma gas discharge part to generate excessive heat. By introducing the plasma functional liquid into the solvent in the plasma functional liquid generation tank in the form of bubbles without any pressure fluctuation, it is possible to obtain a plasma functional liquid that contains long-lived active species and has excellent cleaning and sterilizing effects.

1 is a schematic diagram showing the configuration of a plasma functional liquid manufacturing apparatus according to a first embodiment of the present invention. It is a schematic diagram showing the composition of the plant cultivation plant concerning the 2nd embodiment of the present invention. It is a schematic diagram which shows the structure of the plant cultivation plant based on the 1st modification of 2nd Embodiment. It is a schematic diagram which shows the structure of the plant cultivation plant based on the 2nd modification of 2nd Embodiment. It is a schematic diagram which shows the structure of the plant cultivation plant based on the 3rd modification of 2nd Embodiment. FIG. 2 is a schematic diagram showing an experimental procedure regarding an experimental example. 3 is a graph showing experimental results of Experimental Example 1. FIG. 2 is a schematic diagram showing an experimental procedure regarding Experimental Example 2. 7 is a graph showing the experimental results of Experimental Example 2. 7 is a graph showing the experimental results of Experimental Example 3. 7 is a graph showing experimental results of Experimental Example 4. 7 is a graph showing the experimental results of Experimental Example 5.

Various embodiments of the present invention will be described based on the drawings. In addition, in the following, when referring to the number, numerical value, amount, range, etc. of constituent elements, the term is limited to that specific number, unless it is specifically specified or it is clearly limited to a specific number in principle. It doesn't matter if it's more than or less than a certain number.

In addition, when referring to the shape or positional relationship of constituent elements, etc., unless it is specifically specified or it is clearly considered that it is not the case in principle, etc., we refer to things that are substantially similar to or similar to the shape, etc. include.

Further, in the drawings, characteristic parts may be enlarged or exaggerated in order to make the features easier to understand, and the dimensional ratios of the constituent elements are not necessarily the same as in reality. Further, in the cross-sectional views, hatching of some components may be omitted in order to make the cross-sectional structure of the components easier to understand.

<First embodiment>
First, a plasma functional liquid manufacturing apparatus 10 according to a first embodiment of the present invention will be described based on the drawings. FIG. 1 is a schematic diagram showing the configuration of a plasma functional liquid manufacturing apparatus 10. As shown in FIG. The plasma functional liquid manufacturing apparatus 10 produces a plasma functional liquid L having excellent cleaning and sterilizing effects.

The plasma functional liquid manufacturing apparatus 10 includes a plasma head 20 that is a plasma gas generating section. The plasma head 20 may have any configuration as long as it generates plasma, but an atmospheric pressure plasma device that generates plasma at a pressure near atmospheric pressure is preferable. Atmospheric pressure plasma devices are smaller in device size, superior in operability, and higher in safety than low pressure plasma devices such as vacuum plasma devices. Furthermore, atmospheric pressure plasma devices can generate a higher concentration of active species than low pressure plasma devices.

Inside the plasma head 20, a plate-shaped first electrode 21 and a second plate-shaped electrode 22 are provided facing each other with a gap between them. A high frequency voltage is applied to the first electrode 21 by a power source 23 . Further, the second electrode 22 is connected to ground 24 .

Plasma generation gas is sent to the space between the first electrode 21 and the second electrode 22 via a compressor 25. The plasma generating gas is a gas that generates plasma and contains at least oxygen gas. The oxygen concentration of the plasma-generating gas is preferably 90% or more, preferably 90% or more and 95% or less, which provides excellent cleaning and sterilization effects. The oxygen concentration of the plasma-generating gas may be adjusted in advance using an oxygen concentrator (not shown) as necessary. Note that when the oxygen concentration of the plasma-generating gas is less than 100%, the plasma-generating gas contains nitrogen components and the like. In particular, if a plasma-generating gas with an oxygen concentration of 95% is generated using an oxygen concentrator using the PSA method, which generates high-concentration oxygen by adsorbing nitrogen in the air onto zeolite, theoretically the oxygen concentration will be 0.5%. Contains a certain amount of nitrogen. The nitrogen component of the plasma generating gas is preferably 5% or less.

The plasma head 20 is connected to a plasma gas discharge section 30 via a gas transport path 31. Since the plasma head 20 and the plasma gas emitting section 30 are separated from each other, heat generated within the plasma head 20 is suppressed from being transmitted to the plasma gas emitting section 30.

The gas transport path 31 has one end connected to the plasma head 20 and the other end connected to the plasma gas discharge section 30 , and sends the plasma gas generated by the plasma head 20 to the plasma gas discharge section 30 . Note that the plasma gas is pressurized to such an extent that backflow from the plasma gas discharge section 30 to the plasma head 20 is suppressed.

The plasma gas discharge section 30 is immersed in a liquid in a plasma functional liquid generation tank 41, which will be described later. The plasma gas emitting section 30 is, for example, a porous member formed in a hollow, substantially cylindrical shape and having a large number of holes 32 formed on its outer peripheral surface. The plasma gas discharge unit 30 allows the plasma gas supplied therein to pass through the holes 32, thereby introducing bubbles B of the plasma gas into the solvent S in the plasma functional liquid generation tank 41.

The diameter of the hole 32 can be set to any size depending on the diameter of the bubbles B introduced into the solvent S in the plasma functional liquid generation tank 41. For example, depending on the diameter of the pores 32, microbubbles with a bubble diameter of about 1 μm to 100 μm or ultrafine bubbles with a bubble diameter of about several tens of nanometers to 1 μm can be generated.

The bubbles B contain active species such as ozone, hydrogen peroxide, hydroxide radicals, nitrogen oxides, and singlet oxygen, depending on the type of plasma-generating gas. In this specification, "active species" refers to radicals generated by activation of plasma-generating gas by plasma. The radicals contained in the plasma gas differ depending on the type of plasma-generating gas used to generate the plasma gas. For example, when the plasma-generating gas contains an oxygen component, oxygen radicals are generated, and nitrogen components are generated in the plasma-generating gas. is included, nitrogen oxide radicals are generated. In addition, nitrate nitrogen (nitrate radical) is useful for plant growth.

The plasma gas discharge part 30 is made of metal, ceramics, or plastic, preferably copper, silver, or an alloy thereof. Thereby, copper ions or silver ions can be introduced into the solvent S.

The plasma functional liquid manufacturing apparatus 10 includes a plasma functional liquid generating section 40 that generates a plasma functional liquid L. In this specification, "plasma functional liquid L" refers to a solution in which active species retained in plasma gas are retained in bubbles B in solvent S and then gradually dissolved in solvent S. That is, the plasma functional liquid L contains active species held in the bubbles B or active species dissolved in the solvent S. By dissolving the active species in the solvent S, the solvent S itself is cleaned and sterilized, and the plasma functional liquid L also cleans and sterilizes other objects.

The plasma functional liquid generation section 40 includes a plasma functional liquid generation tank 41 that stores a solvent S and immerses the plasma gas discharge section 30 in the solvent S. The plasma functional liquid generation tank 41 is not provided with stirring blades or the like for stirring the solvent S, and the generation of air current in the solvent S is suppressed. The solvent S is, but is not limited to, water such as ultrapure water, ion-exchanged water, purified water, or distilled water, a solution containing inorganic nutrients, or liquid fertilizer. Note that when a liquid fertilizer is used as the solvent S, the plasma functional liquid L can sterilize fungi contained in the liquid fertilizer, and the liquid fertilizer can contain active species suitable for plant growth.

The bubbles B are preferably microbubbles or ultrafine bubbles that are retained in the solvent S for a long time. In particular, when the bubbles B are ultra-fine bubbles, almost no buoyancy acts on the bubbles B, so that the bubble state is maintained for a long time.

In this way, the plasma functional liquid manufacturing apparatus 10 according to the present embodiment includes the plasma head 20 that generates plasma gas containing active species from plasma generation gas, and the plasma gas discharge section 30 that discharges plasma gas in the form of bubbles. , a plasma functional liquid generation unit 40 that includes a plasma functional liquid generation tank 41 that stores a solvent S, and a plasma functional liquid generation unit 40 that generates a plasma functional liquid L by introducing plasma gas in a bubble state into the solvent S, and The concentration was set to be 90% or more.

According to this configuration, a plasma gas holding active species having an excellent cleaning effect and sterilization effect is generated from the plasma generation gas having an oxygen concentration of 90% or more, and this plasma gas flows through the holes 32 of the plasma gas discharge part 30. The plasma functional liquid, which contains long-lived active species and has excellent cleaning and sterilizing effects, is passed through and introduced into the solvent S in the plasma functional liquid generation tank 41 in the form of bubbles without generating heat or pressure fluctuations. You can get L.

Furthermore, the plasma functional liquid manufacturing apparatus 10 according to the present embodiment has a configuration in which the plasma generating gas has an oxygen concentration of 90% or more and 95% or less.

According to this configuration, plasma generation gas can be easily obtained using a small oxygen concentrator, and the generation of ozone that is generated when the oxygen concentration is excessively high is suppressed, which improves workability and economy. A plasma functional liquid L having excellent properties can be obtained.

Further, the plasma functional liquid manufacturing apparatus 10 according to the present embodiment has a configuration in which the nitrogen concentration of the plasma generating gas is 0.5% or more.

According to this configuration, since nitrate ions derived from nitrogen gas contained in the plasma generation gas are dissolved in the plasma functional liquid L, it is possible to obtain a plasma functional liquid L suitable for plant growth.

Furthermore, in the plasma functional liquid manufacturing apparatus 10 according to the present embodiment, the plasma head 20 is disposed outside the plasma functional liquid generation tank 41, and the plasma gas discharge section 30 is configured to dispose of the solvent stored in the plasma functional liquid generation tank 41. The structure is such that it is a porous member that is immersed in S and releases plasma gas in the form of bubbles when the plasma gas passes through it.

According to this configuration, the plasma head 20 is arranged outside the plasma functional liquid generation tank 41, and the plasma gas is introduced into the solvent S from the plasma gas discharge part 30 immersed in the solvent S. It is possible to suppress the activity of the active species contained in the plasma functional liquid L from being lost due to the heat generated during generation, and the lifespan of the active species can be extended.

Further, in the plasma functional liquid manufacturing apparatus 10 according to the present embodiment, the plasma gas discharge section 30 is made of copper, silver, or an alloy thereof.

According to this configuration, the copper ions or silver ions eluted from the plasma gas discharge part 30 are introduced into the solvent S, so that the cleaning effect and the sterilization effect of the plasma functional liquid L can be enhanced.

Moreover, the plasma functional liquid manufacturing apparatus 10 according to the present embodiment has a configuration in which the plasma gas bubbles are microbubbles or ultrafine bubbles.

According to this configuration, since the bubbles B are retained for a long time, the active species contained in the plasma functional liquid L can be maintained for a long time.

<Second embodiment>
Next, a plant plant 1A according to a second embodiment of the present invention will be described based on the drawings. FIG. 2 is a schematic diagram showing the configuration of a plant plant 1A according to the second embodiment. The plant plant 1A includes a cultivation tank 2 for hydroponically cultivating plants P, and a plasma functional liquid manufacturing device 10.

The cultivation tank 2 includes a container 2a that stores a solution A containing liquid fertilizer, and a support part 2b that supports the plant P so that the underground part of the plant P reaches the solution A in the container 2a.

The plasma functional liquid generation section 40 includes a liquid supply path 42 as a discharge section that sends the plasma functional liquid L to the container 2a. The liquid supply path 42 has an upstream end connected to the plasma functional liquid generation tank 41, and a downstream end connected to the container 2a. The plasma functional liquid L sent through the liquid supply path 42 is pumped using a pump or the like (not shown) and mixed with the solution A. Note that solution A does not necessarily have to contain liquid fertilizer.

In this way, the plasma functional liquid L generated by the plasma functional liquid manufacturing device 10 is sent to the cultivation tank 2 via the liquid supply path 42, and the solution A in the cultivation tank 2 is sterilized or sterilized by the plasma functional liquid L. Therefore, the plants P can grow well.

<Modification 1>
Next, a modification of the plant 1A according to the second embodiment will be described based on the drawings. FIG. 3 is a schematic diagram showing the configuration of a plant plant 1B according to this modification. Note that the plant plant 1B according to this modification differs from the plant plant 1A according to the second embodiment described above in the following points, and the other configurations are common. Therefore, common configurations are given the same reference numerals and redundant explanations will be omitted.

The solution A in the container 2a and the solvent S in the plasma functional liquid generation tank 41 both contain liquid fertilizer. Furthermore, the plasma generation gas contains a nitrogen component, and the plasma functional liquid contains nitrate nitrogen (nitric acid radicals), which is a nutrient for plants.

The plasma functional liquid generation section 40 includes a liquid circulation path 43 that connects the container 2a and the plasma functional liquid generation tank 41. The liquid circulation path 43 has an upstream end connected to the container 2a, and a downstream end connected to the plasma functional liquid generation tank 41. The solution and plasma functional liquid L in the container 2a are returned from the container 2a to the plasma functional liquid generation tank 41 via a liquid circulation path 43 by a pump or the like (not shown). That is, the solution A circulates through the container 2a and the plasma functional liquid generation tank 41 via the liquid supply path 42 and the liquid circulation path 43.

The solution refluxed from the container 2a was mixed into the solvent S stored in the plasma functional liquid generation tank 41, and the plasma gas bubbles B released from the plasma gas discharge part 30 were stored in the plasma functional liquid generation tank 41. Introduced into solvent S. In this way, the plasma functional liquid L in which active species are dissolved circulates between the plasma functional liquid generating section 40 and the cultivation tank 2.

Furthermore, since the lifespan of the liquid fertilizer contained in the solvent S and solution A as a fertilizer is longer than the lifespan of the active species, the liquid fertilizer can be used repeatedly by continuing to supply the active species as described above. .

<Modification 2>
Next, another modification of the plant 1A according to the second embodiment will be described based on the drawings. FIG. 4 is a schematic diagram showing the configuration of a plant plant 1C according to this modification. Note that the plant plant 1C according to this modification differs from the plant plant 1A according to the second embodiment described above in the following points, and the other configurations are common. Therefore, common configurations are given the same reference numerals and redundant explanations will be omitted.

The plant plant 1C includes a cultivation container 3 for cultivating a plant P planted in culture soil or the like, and a plasma functional liquid manufacturing device 10.

The plasma functional liquid generation section 40 includes a liquid supply pipe 44 as a discharge section and a spray head 45. It is connected. The plasma functional liquid L sent through the liquid supply pipe 44 is pumped using a pump or the like (not shown). The liquid supply pipe 44 preferably has flexibility.

The spray head 45 sprays the plasma functional liquid L to the outside. The flowers, leaves, stems, fruits, etc. of the plants P sprayed with the plasma functional liquid L are sterilized or sterilized by the active species contained in the plasma functional liquid L.

By using an atmospheric pressure plasma device for the plasma head 20, the plasma functional liquid manufacturing device 10 can be configured to be lightweight and safe, and the plasma functional liquid manufacturing device 10 can be downsized to the extent that it is portable. Therefore, the user can carry the plasma functional liquid manufacturing device 10 close to the cultivation container 3 and spray the plasma functional liquid L toward any plant P. Note that the plasma functional liquid manufacturing apparatus 10 is not limited to one that sprays the plasma functional liquid L onto the plants P, and may be one that drips the plasma functional liquid L onto the plants P.

<Modification 3>
Next, another modification of the plant 1A according to the second embodiment will be described based on the drawings. FIG. 5 is a schematic diagram showing the configuration of a vegetable plant 1D according to this modification. Note that the plant plant 1D according to this modification differs from the plant plant 1A according to the second embodiment described above in the following points, and the other configurations are common. Therefore, common configurations are given the same reference numerals and redundant explanations will be omitted.

The plant plant 1D includes three cultivation containers 4 for cultivating plants P planted in culture soil or the like, and a plasma functional liquid manufacturing device 10.

The plasma functional liquid generation section 40 includes a liquid supply pipe 46 as a discharge section and three spray heads 47.

The liquid supply pipe 46 has a base end connected to the plasma functional liquid generation tank 41, branches into three parts in the middle, and has a distal end connected to each spray head 47, respectively. The plasma functional liquid L sent through the liquid supply pipe 46 is pumped using a pump or the like (not shown).

The spray head 47 is positioned above each cultivation container 4 and sprays the plasma functional liquid L toward the cultivation container 4, respectively. The flowers, leaves, stems, fruits, etc. of the plants P sprayed with the plasma functional liquid L are sterilized or sterilized by the active species contained in the plasma functional liquid L. Note that the number of spray heads 47 can be increased or decreased depending on the number of plants P and cultivation containers 4 and the range in which the spray heads 47 spray the plasma functional liquid L.

The operation of the spray head 47 is controlled by a controller 48 . The controller 48 controls the timing and amount at which the spray head 47 sprays the plasma functional liquid L, depending on the temperature acquired by a sensor (not shown) and the growth status of the plant P. Note that the plasma functional liquid manufacturing apparatus 10 is not limited to one that sprays the plasma functional liquid L onto the plants P, and may be one that drips the plasma functional liquid L onto the plants P.

(Experiment example 1)
A comparative experiment was conducted on the sterilizing effects of each plasma gas generated when oxygen, carbon dioxide, air, and nitrogen were used as plasma generation gases.

First, 248 ml of purified water and 2 ml of spore suspension were mixed to prepare 250 ml of spore suspension. Fusarium oxysporum f.sp. fragariae: NBRC 31982 was used for the spores in the spore solution. These spores are mainly responsible for strawberry yellowing disease, and by eradicating or sterilizing strawberries, the disease can be controlled and growth inhibition and death can be suppressed.

Next, as shown in FIG. 6, 50 ml of the spore suspension was placed in a beaker 101 and subjected to plasma treatment using plasma gas using a plasma bubbling device 100. Plasma gas generated by the multi-gas plasma jet 102, which is a plasma generation part, is sent via a cylindrical pipe 103 to a porous filter 104, which is a plasma gas discharge part, which is immersed in the spore suspension. The spores are introduced into the spore suspension through the quality filter 104 in the form of bubbles. The length of the cylindrical pipe 103 was set to about 90 mm, the length of the porous filter 104 was set to about 20 mm, and the flow rate of the plasma gas introduced was set to 3 SLPM.

Four types of plasma generation gases, oxygen, carbon dioxide, air, and nitrogen, are prepared as plasma generation gases used to generate plasma gas, and the plasma gases generated from each are introduced into the spore suspension in the form of bubbles. The time (processing time) was set to 0 seconds, 120 seconds, 300 seconds, and 600 seconds.

Then, 1 ml of the spore suspension into which bubbled plasma gas had been introduced was serially diluted and then dropped onto an agar medium placed in Petri dish 105, and the amount of germinated spores was counted after culturing at room temperature for 2 days. The results are shown in FIG.

According to FIG. 7, it took 120 seconds for the plasma gas when oxygen gas was used as the plasma generation gas, and for over 300 seconds for the plasma gas when carbon dioxide gas was used as the plasma generation gas, and for more than 300 seconds when air was used as the plasma generation gas. It can be seen that an excellent sterilizing effect can be obtained by introducing plasma gas by bubbling for 600 seconds or more. On the other hand, it can be seen that the sterilizing effect of plasma gas when nitrogen gas is used as the plasma generation gas is smaller than that of plasma gas generated from oxygen, carbon dioxide, or air. From these results, it can be seen that the use of oxygen gas as the plasma generating gas is most effective.

(Experiment example 2)
Next, an experiment was conducted to verify the relationship between the oxygen concentration of the oxygen gas contained in the plasma generation gas and the sterilizing effect of the plasma gas.

As shown in FIG. 8, 50 ml of purified water was placed in a beaker 101, and plasma gas was introduced into the purified water using a plasma bubbling device 100. Specifically, plasma gas generated by a multi-gas plasma jet 102 that is a plasma generation section is sent via a cylindrical pipe 103 to a porous filter 104 that is a plasma gas discharge section that is immersed in purified water. and introduced into purified water in the form of bubbles through the porous filter 104. The length of the cylindrical pipe 103 was set to about 90 mm, the length of the porous filter 104 was set to about 20 mm, and the flow rate of the plasma gas introduced was set to 3 SLPM.

The following five types of plasma generation gas were prepared, and the time (processing time) for introducing the plasma gas generated from each into purified water in the form of bubbles was set to 60 seconds and 300 seconds.
・Plasma generation gas 1: 100% air (21% oxygen, 78% nitrogen, 1% argon)
・Plasma generation gas 2: 40% oxygen, 58% nitrogen, 2% argon
・Plasma generation gas 3: 70% oxygen, 27% nitrogen, 3% argon
・Plasma generation gas 4: 90% oxygen, 6% nitrogen, 4% argon
・Plasma generation gas 5: 100% oxygen

Then, 10 μl of the spore liquid was mixed with 990 μl of purified water into which bubbled plasma gas had been introduced, and the mixture was allowed to stand for 10 minutes to prepare a spore suspension. Fusarium oxysporum f.sp. fragariae: NBRC 31982 was used for the spores in the spore solution. Then, 1 ml of the spore suspension was serially diluted and dropped onto an agar medium placed in Petri dish 105, and after culturing at room temperature for 2 days, the number of viable bacteria was counted. The results are shown in FIG.

According to Figure 9, when the oxygen concentration of the plasma-generating gas was set to 90% and 100%, the number of viable bacteria decreased significantly at bubbling times (processing times) of 60 seconds and 300 seconds, and a remarkable sterilization effect was observed. It was done. On the other hand, when the oxygen concentration of the plasma-generating gas is set to 21% oxygen, 40% oxygen, or 70% oxygen, the reduction in the number of viable bacteria, that is, the sterilization effect, is smaller than when the oxygen concentration is 90% or 100%.

(Experiment example 3)
Next, an experiment was conducted to verify in more detail the relationship between the oxygen concentration of the oxygen gas contained in the plasma-generating gas and the sterilizing effect of the plasma gas.

In the same manner as in Experimental Example 2, a spore suspension was prepared by mixing 990 μl of purified water into which bubbled plasma gas had been introduced with 10 μl of the spore liquid. As in Experimental Example 2, Fusarium oxysporum f.sp. fragariae: NBRC 31982 was used as the spores in the spore liquid.

The following three types of plasma generation gas were prepared, and the time (processing time) for introducing the plasma gas generated from each into purified water in the form of bubbles was set to 10 seconds, 20 seconds, 30 seconds, and 60 seconds. Then, in the same manner as in Example 2, 1 ml of the spore suspension was serially diluted and then dropped onto an agar medium placed in Petri dish 105, and the number of surviving bacteria was counted after culturing at room temperature for 2 days. The results are shown in FIG.
・Plasma generation gas 6: 80% oxygen, 17% nitrogen, 3% argon
・Plasma generation gas 7: 90% oxygen, 6% nitrogen, 4% argon
・Plasma generation gas 8: 100% oxygen

According to FIG. 10, when the oxygen concentration of the plasma generation gas is set to 90% or 100%, the number of viable bacteria decreases significantly and a remarkable sterilization effect can be obtained with bubbling time (processing time) of 10 seconds or more. I understand. On the other hand, when the oxygen concentration of the plasma generating gas is set to 80%, the reduction in the number of viable bacteria, that is, the sterilizing effect, is smaller than when the oxygen concentration is 90% or 100%.

Although the plasma generation gas 4 in Experimental Example 2 and the plasma generation gas 7 in Experimental Example 3 were tested with the same components, the number of spores per unit volume of the spore liquid used in the experiment varied in each experiment. Since the number of viable bacteria before culturing in a petri dish is different, the absolute values of the number of viable bacteria in FIGS. 9 and 10 are different. The same applies to the plasma generating gas 5 of Experimental Example 2 and the plasma generating gas 8 of Experimental Example 3.

(Experiment example 4)
Next, an experiment was conducted to verify in more detail the relationship between the oxygen concentration of the oxygen gas contained in the plasma generation gas and the sterilization effect of the plasma gas when the processing time was set to 60 seconds.

In the same manner as in Experimental Example 3, 990 μl of purified water into which bubbled plasma gas had been introduced was mixed with 10 μl of the spore liquid to prepare a spore suspension. As in Experimental Example 3, Fusarium oxysporum f.sp. fragariae: NBRC 31982 was used as the spores in the spore liquid.

The following seven types of plasma generating gases were prepared, and the plasma gases in the form of bubbles generated from each were introduced into purified water for 60 seconds. Then, in the same manner as in Example 2, 1 ml of the spore suspension was serially diluted and then dropped onto an agar medium placed in Petri dish 105, and the number of surviving bacteria was counted after culturing at room temperature for 2 days. The results are shown in FIG. In FIG. 11, the horizontal axis represents the following plasma-generating gases 9 to 15, and the vertical axis represents the number of viable bacteria. Note that the broken line in FIG. 11 indicates the number of bacteria at the start of this experiment (initial number of bacteria).
・Plasma generation gas 9: 80% oxygen, 17% nitrogen, 3% argon
・Plasma generation gas 10: 85% oxygen, 11% nitrogen, 4% argon
・Plasma generation gas 11: 90% oxygen, 6% nitrogen, 4% argon
・Plasma generation gas 12: 94% oxygen, 1% nitrogen, 5% argon
・Plasma generation gas 13: 95% oxygen, 0% nitrogen, 5% argon
・Plasma generation gas 14: 99% oxygen, 1% nitrogen, 0% argon
・Plasma generation gas 15: 100% oxygen, 0% nitrogen, 0% argon

According to FIG. 11, when plasma generation gas 9 to 10 is used, the reduced number of bacteria, which is the difference between the initial number of bacteria and the number of viable bacteria, is less than 1 in logarithmic representation, that is, less than 1/10 in linear representation. I understand. On the other hand, when plasma-generating gases 11 to 15 are used, it can be seen that the reduction in the number of bacteria is 1 or more in logarithmic representation, that is, 1/10 or more in linear representation.

(Experiment example 5)
In Examples 1 to 4, Fusarium oxysporum f.sp. fragariae: NBRC 31982 was used as the spores in the spore liquid, but in this example, the bactericidal effect on bacteria other than Fusarium oxysporum f.sp. fragariae: NBRC 31982 was evaluated. Verified. In this example, a bacterial solution containing the following three types of bacteria and one type of spore solution were used, and in the same manner as in Experimental Example 3, 990 μl of purified water into which bubbled plasma gas was introduced was used to collect the bacterial solution or spore solution. A bacterial suspension or a spore suspension was prepared by mixing with 10 μl of the solution.
・Bacterial liquid 1: S. aureus (Staphylococcus aureus)
・Bacterial liquid 2: E.coli (E. coli)
・Bacterial liquid 3: P. aeruginosa (Pseudomonas aeruginosa)
・Spore liquid 1: gray mold fungus

The following two types of plasma generating gases with different oxygen concentrations were prepared using a PSA type oxygen concentrator. Note that the nitrogen concentration and argon concentration in the plasma generation gases 16 to 17 are estimated values.
・Plasma generation gas 16: 90% oxygen, 5.7% nitrogen, 4.3% argon
・Plasma generation gas 17: 95% oxygen, 0.5% nitrogen, 4.5% argon

Then, plasma gas generated from the plasma generation gas was introduced into the purified water in the form of bubbles for 60 seconds. Then, in the same manner as in Example 2, 1 ml of the spore suspension was serially diluted and then dropped onto an agar medium placed in Petri dish 105, and the number of surviving bacteria was counted after culturing at room temperature for 2 days. The results are shown in FIG. In FIG. 12, the horizontal axis is the above-mentioned bacterial liquids 1 to 3 and spore liquid 1, and the vertical axis is the initial bacterial count and the plasma-generated gas 16 to 17 used in the bacterial liquids 1 to 3 and spore liquid 1. This is the number of viable bacteria in the case.

According to FIG. 12, by using plasma-generating gas with an oxygen concentration of 90% and 95% for both bacterial solutions 1 to 3 and spore solution 1, the difference between the initial number of bacteria and the number of surviving bacteria is It can be seen that the reduced number of bacteria is 1 or more in logarithmic representation, that is, 1/10 or more in linear representation.

As described above, according to Example 1, oxygen gas is very effective as a plasma generating gas, and in particular, when the oxygen concentration is at least 90% or more, a remarkable sterilizing effect can be obtained. This can be seen from 2 to 4. Furthermore, according to Experimental Example 5, by using oxygen gas as the plasma-generating gas, in addition to Fusarium oxysporum f.sp. It can be seen that it exhibits an effective bactericidal effect against Staphylococcus aureus), E. coli, P. aeruginosa, and gray mold.

However, when the oxygen concentration is set higher than 95%, a very expensive high-concentration oxygen generator is required and is not practical, whereas when the oxygen concentration is set below 95%, a small oxygen concentrator is required. It is possible to use a container. Furthermore, if the oxygen concentration is excessively high, the amount of ozone produced increases, which may have an impact on the human body, plants, etc. In particular, when the oxygen concentration is higher than 95%, ozone introduced into the liquid does not dissolve into the liquid and is released into the air, so separate ozone countermeasures are required. Therefore, in consideration of workability and cost, the oxygen concentration is preferably 90% or more and 95% or less.

When the oxygen concentration is 95% or less, the plasma generating gas also contains nitrogen gas. Therefore, nitrate ions, which function as nutrients for plant growth, are generated in the active species in the plasma functional liquid L.

Further, the present invention can be modified in various ways other than those described above without departing from the spirit of the invention, and it goes without saying that the present invention extends to such modifications.

1A, 1B, 1C, 1D: Plant plant 2: Cultivation tank 2a: Container 2b: Support part 3: Cultivation container 4: Cultivation container 10: Plasma functional liquid manufacturing device 20: Plasma head 21: First electrode 22: Second Electrode 23: Power supply 24: Earth 25: Compressor 30: Plasma gas discharge section 31: Gas transport path 32: Hole 40: Plasma functional liquid generation section 41: Plasma functional liquid generation tank 42: Liquid supply path 43: Liquid circulation path 44 , 46: Liquid supply pipe 45, 47: Spray head 48: Controller A: Solution B: Bubbles L: Plasma functional liquid P: Plant S: Solvent

Claims (14)

a plasma gas generation unit that generates plasma gas containing active species from plasma generation gas;
a plasma gas discharge unit that discharges the plasma gas in the form of bubbles;
a plasma functional liquid generation unit that includes a plasma functional liquid generation tank that stores a solvent and generates a plasma functional liquid by introducing the plasma gas in a bubble state into the solvent;
Equipped with
A plasma functional liquid manufacturing apparatus characterized in that the plasma generating gas has an oxygen concentration of 90% or more. 2. The plasma functional liquid manufacturing apparatus according to claim 1, wherein the plasma generating gas has an oxygen concentration of 90% or more and 95% or less. The plasma functional liquid manufacturing apparatus according to claim 1 or 2, wherein the nitrogen concentration of the plasma generating gas is 0.5% or more. The plasma gas generation section is arranged outside the plasma functional liquid generation tank,
4. The plasma gas discharge section is a porous member that is immersed in a solvent stored in the plasma functional liquid generation tank and discharges the plasma gas in the form of bubbles. The plasma functional liquid manufacturing device according to item 1. 5. The plasma functional liquid manufacturing apparatus according to claim 4, wherein the porous material member is made of copper, silver, or an alloy thereof. 6. The plasma functional liquid manufacturing apparatus according to claim 1, wherein the plasma gas bubbles are microbubbles or ultrafine bubbles. The plasma according to any one of claims 1 to 6, wherein the plasma functional liquid generation section includes a discharge section capable of discharging the plasma functional liquid to the outside of the plasma functional liquid generation tank. Functional fluid manufacturing equipment. The plasma functional liquid manufacturing apparatus according to claim 7,
A cultivation container for cultivating plants;
Equipped with
The plant cultivation plant is characterized in that the discharge section drips or sprays the plasma functional liquid onto the plant. The plasma functional liquid manufacturing apparatus according to claim 7,
A cultivation tank for cultivating plants hydroponically,
Equipped with
The plant cultivation plant, wherein the discharge section supplies the plasma functional liquid to the cultivation tank. the solvent is a liquid fertilizer;
The plasma generating gas contains at least nitrogen,
10. The plant according to claim 9, wherein the plasma functional liquid generation unit includes a reflux path for circulating the plasma functional liquid supplied to the cultivation tank from the cultivation tank to the plasma functional liquid generation tank. cultivation plant. a plasma gas generation unit that generates plasma gas containing active species from plasma generation gas;
a plasma gas discharge unit that discharges the plasma gas in the form of bubbles;
a plasma functional liquid generation unit that includes a plasma functional liquid generation tank that stores a solvent and generates a plasma functional liquid by introducing the plasma gas in a bubble state into the solvent;
A plasma functional liquid manufacturing method using a plasma functional liquid manufacturing apparatus comprising:
A method for producing a plasma functional liquid, wherein the plasma generating gas has an oxygen concentration of 90% or more. 12. The method for producing a plasma functional liquid according to claim 11, wherein the plasma generating gas has an oxygen concentration of 90% or more and 95% or less. The plasma functional liquid manufacturing method according to claim 11 or 12, wherein the nitrogen concentration of the plasma generating gas is 0.5% or more. The plasma gas generation section is arranged outside the plasma functional liquid generation tank,
A porous member of the plasma gas discharge section is immersed in a solvent stored in the plasma functional liquid generation tank, and discharges the plasma gas in the form of bubbles when the plasma gas passes through the porous member. The method for producing a plasma functional liquid according to any one of Items 11 to 13.

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