JP7032729B2 - Nitrate ion and nitrite ion concentration detection method and concentration detection device and plant growth / life-prolonging agent manufacturing device - Google Patents

Description

It relates to a method and an apparatus for detecting the concentration of nitrate ion and nitrite ion contained in a liquid, and an apparatus for producing a plant growth / life-prolonging agent using the apparatus.

It is well known that nitrates are administered for the purpose of maintaining the freshness of flowers, especially cut flowers (see, for example, Patent Document 1). Further, a method of generating nitrate ion or nitrite ion by plasma discharge has been devised (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2008-239506 Japanese Unexamined Patent Publication No. 2016-214207 Japanese Unexamined Patent Publication No. 2004-07738

The technique disclosed in Patent Document 2 described above is to generate plasma in an atmosphere containing oxygen and nitrogen, and bring the plasma into contact with a liquid to generate plasma-treated water. Assuming that nitrite ion is contained and may contain nitrate ion, hydrogen ion and hydrogen peroxide, for example, when plasma is generated for 30 minutes with an input power of 30 W for 300 ml of tap water, nitrate is generated. It is said that plasma-treated water having an ion concentration of 100 ppm can be produced. Further, various sensors are provided to detect the concentration of nitrate ion and the concentration of contained ions such as nitrite ion.

However, regarding various sensors for detecting various ion concentrations, the above-mentioned Patent Document 2 does not show a specific configuration, and a general ion concentration sensor uses a substance sensitive to the ions as an electrode. It was a thing. For example, in a sensor for detecting a nitrate ion concentration, a nitrate ion sensitive film is used as an electrode as disclosed in Patent Document 3. However, when a sensitive film type ion concentration sensor is used, since the potential of the liquid containing nitrate ion is measured, the nitrate ion sensitive substance is used for the electrode, and when energized, the nitrate ion sensitive substance is contained in the nitrate ion sensitive substance. There was concern that the liquid used for plants such as cut flowers would be altered by the elution of a specific substance into the liquid.

In addition, when measuring the ion concentration with an ion sensor, and when measuring the transmitted light with an ultraviolet-visible spectrophotometer, sampling measurement is required and it is complicated because it is compared with the result of sampling measurement. I had no choice but to become.

Further, although it is shown in Patent Document 2 that nitrate ion or nitrate ion is contained in the liquid by irradiating the liquid (tap water, distilled water, etc.) with atmospheric pressure plasma, the above-mentioned ion Regardless of which one is contained, it was thought that it would be effective as a nutrient water for promoting the growth of plants such as flowers and prolonging the life of cut flowers. However, according to the research by the inventors of the present application, nitrate ion is nitrite. It turned out to be more effective than ion. In addition to being effective as a life-prolonging agent for cut flowers, liquids containing nitrate ions are also effective for rooting, germination, flowering, fruiting, fruit set, etc. in plants such as flowers. Is assumed. Therefore, a method and a detection device capable of immediately measuring the concentration of nitrate ions in the treated water subjected to plasma treatment have been eagerly desired.

Furthermore, nitrate ions are effective for liquids used for growing plants such as flowers and prolonging the life of cut flowers, but even if the liquid is irradiated with atmospheric pressure plasma, nitrate ions should be at the desired concentration. In order to do so, long-term plasma irradiation is required. However, when plasma is applied to the entire stored liquid, the treated water is measured after temporarily suspending plasma irradiation in order to confirm whether or not the nitrate ion has reached the desired concentration. A device that can measure the nitrate ion concentration while continuously irradiating plasma has also been eagerly awaited.

The present invention has been made in view of the above points, and an object thereof is to incorporate a method and an apparatus capable of measuring the concentrations of nitrate ion and nitrite ion by non-contact, and the apparatus. It is to provide a plant growth / life-prolonging agent manufacturing apparatus.

Therefore, the present invention relating to the method for detecting the concentration of nitrate ion and nitrite ion produces the absorbance characteristic only in the light of the first wavelength band which causes the absorbance characteristic in both the nitrate ion and the nitrite ion and in the nitrite ion alone. The liquid to be concentrated is irradiated with the light of the second wavelength band to be concentrated, the absorbance by the nitrite ion is calculated from the transmitted light intensity of the irradiation light of the second wavelength band, and the nitrite is calculated based on the absorbance. The ion concentration is calculated, the absorbance of both nitrate and nitrate ions is calculated from the transmitted light intensity of the irradiation light in the first wavelength band, and the second wavelength band based on the concentration of the nitrite ion is calculated. It is characterized in that the absorbance due to nitrate ion is calculated by subtracting the absorbance in the irradiation light, and the concentration of nitrate ion is calculated based on the absorbance.

According to the detection method having the above configuration, when light in the second wavelength band is irradiated to the liquid whose concentration is to be detected, it is absorbed only by the nitrite ion (NO _2- ⁾ , so that the wavelength in the liquid is concerned. It is possible to calculate the concentration of nitrite ion from the absorbance of. On the other hand, when the liquid whose concentration is to be detected is irradiated with light in the first wavelength band, it is absorbed by both nitrate ion (NO _3- ^{) and} nitrite ion (NO _2- ), so that the same liquid is used. By obtaining the absorbance in the two wavelength bands, the range obtained by subtracting the change in the absorbance based on the concentration of the nitrite ion from the absorbance when the light in the first wavelength band is irradiated is the absorbance by the nitrate ion. As a result, it becomes possible to convert the absorbance into a nitrate ion concentration.

For the conversion method as described above, first, light in the second wavelength band is irradiated, the absorbance due to nitrite ion is calculated from the transmitted light intensity at that time, and further, the absorbance at that time is used. The concentration per mole of nitrite ion (molar concentration) is calculated. The molar concentration can be calculated by Lambert-Beer's law. Simultaneously with the above or next to the above, light in the first wavelength band is irradiated, the absorbance by both nitrate ion and nitrite ion is calculated from the transmitted light intensity at that time, and further, the above-mentioned nitrite ion The absorbance due to nitrate ion is calculated after subtracting the absorbance in the irradiation light in the second wavelength band based on the molar concentration. As a result, the absorbance of the light in the second wavelength band due only to nitrate ion is calculated, and the molar concentration of nitrate ion is calculated based on this absorbance. Then, the total concentration can be calculated from the molar concentration of each of these nitrate ion and nitrite ion.

In the invention according to the concentration detection method having the above configuration, the light in the first wavelength band is light having an arbitrary wavelength in the range of 270 nm to 330 nm, and the light in the second wavelength band is the light. Light having an arbitrary wavelength in the wavelength range of 350 nm to 400 nm is preferable.

According to the above configuration, the absorbance in the liquid can be detected by the intensity of the light transmitted through the liquid to be detected by irradiating with so-called ultraviolet light, and changes according to the change in the concentration of nitrate ion or nitrite ion. The concentration of ions contained in the liquid can be detected from the absorbance of light having a specific wavelength. The reason why the light in the second wavelength band is in the range of the wavelength of 350 nm to 400 nm is that when the light having the wavelength in this band is irradiated, the absorption characteristic due to the nitrate ion does not occur. Further, the reason why the light in the first wavelength band is within the wavelength range of 270 nm to 330 nm is that the absorption characteristic by both nitrate ion and nitrite ion is greatly generated.

If the light in the second wavelength band is approximately 355 nm or approximately 370 nm, the absorption characteristic of the nitrite ion becomes large, so that it is preferable to irradiate the light in the wavelength band. Further, if the light in the first wavelength band is approximately 300 nm, the absorption characteristics due to both nitrate ion and nitrite ion become large, so that it is preferable to irradiate the light in this band. Further, when a light source using an LED is used, 355 nm (measured value 357.8 nm) can be used in the first wavelength band and 310 nm (measured value 309.4 nm) can be used in the second wavelength band.

In the present invention relating to a device for detecting the concentrations of nitrate ions and nitrite ions, voids at appropriate intervals are formed by wall surfaces capable of transmitting light having a wavelength of at least 200 nm to 400 nm by 1% or more, and the voids pass through the liquid whose concentration is to be detected. Alternatively, light emitted within a wavelength range of at least 270 nm to 330 nm and a wavelength of 350 nm to 400 nm is emitted so as to transmit the inspection region constituent portion to be storable and the inspection region constituent portion from the outside of the wall surface of the inspection region constituent portion. It is characterized by including a light source for detecting light intensity and a light detecting unit for detecting the intensity of light emitted from the light source and transmitted through the inspection area constituent unit.

According to the above configuration, by irradiating the concentration detection target liquid with so-called ultraviolet light, the absorbance in the liquid can be detected by the intensity of the light transmitted through the concentration detection target liquid. By detecting this absorbance, the concentration of ions contained in the liquid can be detected from the absorbance of light having a specific wavelength that changes according to the change in the concentration of nitrate ion or nitrite ion. The specific concentration of each ion can be easily calculated based on a calibration curve prepared in advance.

In the invention relating to the concentration detection device having the above configuration, further, a calculation unit for calculating the respective concentrations of nitrate ion and nitrate ion of the concentration detection target liquid from the transmitted light intensity at a specific wavelength is provided, and the inspection area configuration unit is provided. Concentration in the voids The concentration values of nitrate ion and nitrite ion may be calculated by measuring the transmitted light intensity of a specific wavelength transmitted through the liquid to be detected.

In the case of such a configuration, it can be converted into the concentration of nitrate ion and nitrite ion based on the transmitted light intensity of a specific wavelength, that is, the absorbance. That is, by measuring in advance the change in the absorbance at a specific wavelength with respect to each ion concentration in the liquid and creating a calibration curve, various ion concentrations can be obtained based on the detected absorbance at the specific wavelength.

Therefore, in the invention having the above configuration, the light source is a first light source in a wavelength region having absorption characteristics for both nitrate ion and nitrate ion, and a second light source in a wavelength region having absorption characteristics for only nitrate ion. The configuration can be divided into and.

As described above, by irradiating with the second light source, the absorbance when only the nitrite ion has the absorbance characteristic can be measured, so that the concentration of the nitrite ion can be detected from the absorbance. Further, by irradiating with the first light source, the absorbance when both nitrate ion and nitrite ion have absorbance characteristics can be measured, and the nitrite ion concentration is subtracted from the concentration contained in both. , Nitrate ion concentration can be detected. The reason why the concentration of nitrate ion is not directly converted from the absorbance is that there is no wavelength region in which only nitrate ion has an absorbance characteristic in the wavelength range of 200 nm to 400 nm.

In the invention relating to the concentration detection device having the above configuration, the photodetector may alternately detect the transmitted light from the first and second light sources. Further, the light detection unit includes a first detector that detects the intensity of light in a wavelength region having absorption characteristics for both nitrate ion and nitrate ion, and a wavelength region having absorption characteristics for both nitrate ion only. It may be configured to include a second detector for detecting the intensity of light.

Of the above configurations, in the configuration in which the first and second transmitted lights are detected alternately, two types of light sources are used, or a single light source is split into two types using a spectroscope or the like. Thereby, each transmitted light can be detected by a time difference. On the other hand, in the configuration including the first and second detectors, a single light source can be irradiated toward both detectors by a splitter, or irradiation light to different detectors sequentially by a rotation filter. May be released. In addition, two types of detectors may be provided for the two types of light sources, and the irradiation light from each light source may be individually received.

In the invention relating to the concentration detection device having each of the above configurations, the inspection area component portion is configured by a flow path having a side wall formed by the wall surface, and the concentration detection target liquid supplied to the flow path can be used at any time. It can be configured to be irradiated with light.

In the case of the above configuration, since the inspection area component functions as a flow path, continuous concentration detection is possible while flowing the liquid to be concentrated for concentration detection along the flow path. By being able to continuously detect the concentration in this way, it is possible to confirm that the desired concentration has been reached, for example, in the middle of the process of generating (increasing) nitrate ions. In particular, when increasing nitrate ions by irradiating discharge plasma generated by electrical discharge, repeated plasma irradiation is required, so nitrate ions in the liquid whose concentration is to be detected while continuing plasma irradiation. The concentration can be detected sequentially. That is, since sampling is not required, it is not necessary to repeat the sampling measurement many times, which can be saved, and the amount of the final processing liquid is reduced by gradually taking out the liquid for sampling. It will never happen.

The present invention relating to a plant growth / life-prolonging agent manufacturing apparatus uses a nitrate ion and nitrate ion concentration detecting apparatus having the above-mentioned configuration, and lifts a tank for storing liquid and a liquid stored in the tank. A lifting pump that causes a liquid to flow down along a predetermined circulation path, a nitrate ion generating unit that generates nitrate ions in the liquid that flows down along the circulation path, and a section that lifts the liquid from the tank on the upstream side of the circulation path. It is characterized in that it includes an ion concentration measuring unit for measuring the nitrate ion concentration in the liquid to be added, and the nitrate ion concentration measuring unit includes the concentration detecting device and a nitrate ion concentration converting unit. ..

According to the invention having the above configuration, the liquid stored in the tank (initially the undiluted solution before treatment) is pumped up and supplied to the circulation path, so that the liquid can flow down along the circulation path. can. Since the nitrate ion generating portion is provided in the circulation path, the nitrate ion is sequentially increased in the process of the liquid flowing down the circulation path. Since the liquid that has passed through the nitrate ion generating portion is returned to the tank again, the concentration of nitrate ions increases with respect to the entire liquid stored in the tank. Therefore, in order to detect the concentration of nitrate ions in the entire liquid stored in this tank, an ion concentration measuring unit is provided on the upstream side of the circulation path. Since this ion concentration measuring unit is provided with a concentration detecting unit having an inspection area component forming a flow path, the liquid lifted in the tank passes through the flow path of the inspection area component. When flowing down the inspection area component, the ion concentration is detected by the concentration detecting device. Therefore, the liquid can continuously increase the nitrate ion concentration via the nitrate ion generator, and the increased ion concentration is also continuously detected. Therefore, the tank is operated while operating the apparatus. Nitrate ion concentration detection in the entire liquid can be continued to the desired concentration.

In the present invention relating to the plant growth / life-prolonging agent manufacturing apparatus having the above configuration, the nitrate ion generating unit is composed of a plurality of discharge plasma irradiation means, and simultaneously or sequentially with respect to the liquid flowing down along the circulation path. Can be irradiated with discharge plasma.

It is also shown in the above-mentioned Patent Document 2 that nitrate ion or nitrite ion is contained in the liquid by irradiating the liquid with atmospheric pressure plasma, and nitrate ion in the liquid by irradiating the discharge plasma. The concentration can be increased. The liquid to be used is initially a stock solution, but since it is repeatedly irradiated with discharge plasma, the liquid gradually contains nitrate ions.

Here, as the undiluted solution, tap water passing through a water purifier or distilled water can be used, but the undiluted solution is not limited to this, and agricultural water containing other components can also be used. Furthermore, in order to promote the growth or prolong the life of the plant, the above-mentioned distilled water or the like containing sugar or other substances may be used.

According to the present invention relating to the method for detecting the concentration of nitrate ion and nitrate ion, the absorbance of the liquid can be calculated from the transmitted light intensity in the irradiation light in the first and second two wavelength bands, and these absorbances are one of the two. Is the absorbance for only nitrite ion, so the concentration of nitrite ion can be calculated first, and then the absorbance of the other can be used to calculate nitrate ion. Since such a method is based on irradiation of light and detection of transmitted light intensity, density detection can be performed by non-contact. Further, since the wavelength of the light in the first wavelength band is in the range of 270 nm to 330 nm and the wavelength of the light in the second wavelength band is in the range of 350 nm to 400 nm, the wavelength of the light in the second wavelength band is in the range of 350 nm to 400 nm. General-purpose LEDs can be used.

According to the present invention relating to the nitrate ion and nitrite ion concentration detection device, the inspection region component formed by the wall surface that transmits light having at least a predetermined range of wavelength is irradiated with light of a specific wavelength and transmitted. By measuring the light intensity, it is possible to detect the concentration by non-contact. Further, when the void formed in the inspection area constituent portion is used as a flow path, the concentration of each ion can be continuously measured with respect to the flowing liquid. Moreover, since it is non-contact, it can be measured without affecting the flow state of the liquid. Furthermore, it is also possible to measure the nitrate ion concentration in a liquid containing both nitrate ion and nitrite ion.

On the other hand, according to the present invention relating to the plant growth / life-prolonging agent manufacturing apparatus, it is possible to generate (increase) nitrate ions and measure the concentration of nitrate ions while circulating the undiluted solution before being processed into a preservation solution. As a result, the undiluted solution is supplied to the circulation path and circulated to gradually increase the nitrate ion concentration, and by reaching the desired nitrate ion concentration, it is effective in promoting the growth of plants such as flowers or prolonging the life of cut flowers. It is possible to produce a liquid having. Although nitrate ions are generated by irradiation with discharge plasma, the nitrate ion concentration does not increase sharply due to temporary discharge plasma irradiation. Therefore, the nitrate ion concentration is gradually increased while circulating the undiluted solution. Is to raise. In this case, the plasma discharge device is divided into a plurality of groups, and the nitrate ion generation unit is configured to sequentially operate the plasma discharge device of each group, whereby the nitrate ion concentration due to the discharge plasma can be efficiently increased. ..

It is explanatory drawing which shows the outline of embodiment which concerns on the concentration detection apparatus of nitrate ion and nitrite ion. (A) is a graph showing the relationship between the wavelength and the absorbance when irradiated with ultraviolet light, and (b) is a graph showing an example of a calibration curve. It is explanatory drawing which shows the manufacturing method of the calibration curve. It is explanatory drawing which shows the detection method of the density | concentration by the calibration curve. It is explanatory drawing which shows the outline of embodiment which concerns on the manufacturing apparatus of a plant growth | life prolonging agent. It is explanatory drawing which shows the outline of embodiment which concerns on the manufacturing apparatus of a plant growth | life prolonging agent. It is a graph which shows the duty ratio when the plasma irradiation apparatus is grouped.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience of explanation, an embodiment of the ion concentration detection device will be described, and then a method for detecting the ion concentration (nitrate ion concentration) will be described. Finally, an embodiment of the nutrient water production apparatus will be described.

<Nitrate ion concentration detector>
FIG. 1 is a schematic diagram showing an outline of an embodiment relating to a nitrate ion (NO _3- ⁾ and nitrite ion (NO _2- ⁾ concentration detection device. Note that FIG. 1A is a perspective view showing the periphery of the detection device, and FIG. 1B is a cross-sectional view taken along the line BB. As shown in this figure, the present embodiment is emitted from the inspection area constituent unit 1, the light sources 2 and 3 that radiate light to the inspection area constituent unit 1, and the light sources 2 and 3. It is composed of photodetectors 4 and 5 that detect the intensity of light.

The inspection area constituent unit 1 may be such that at least two wall surfaces 11 and 12 are arranged at appropriate intervals and a gap 13 is formed in the intermediate region thereof. In the present embodiment, the flow path is provided. A bottom surface portion 14 and a top surface portion 15 are provided for forming. By supplying the concentration detection target liquid X to the above void 13, the concentration detection target liquid X flows down in the flow path (void 13). The inspection area component 1 may be configured to store the liquid without being a flow path, but it is preferably a flow path when continuous concentration detection is performed. In this case, as shown in FIG. 1 (a), the liquid feeding unit 6 and the flow bottom 7 can be provided. The liquid feeding unit 6 has a structure in which the liquid lifted by a pump or the like is forcibly flowed (supplied) through the supply pipe 61, and the liquid supplied to the liquid feeding unit 6 has an inspection area configuration from the bottom thereof. It is sent to Part 1. Further, in the flow lower portion 7, the liquid that has passed through the inspection area constituent portion 1 is assumed to flow in by natural flow. The flow bottom 7 can be made to function as a nitrate ion generating means by providing a plasma discharge device described later, and further, a tank or the like is provided below the liquid feeding unit 6 and the flow bottom 7 to flow down. A circulation path can be configured by storing the liquid flowing down the portion 7 and providing a lifting pump in the tank.

Further, the wall surfaces 11 and 12 are made of a material capable of transmitting light having a specific wavelength. The light having a specific wavelength is light having a wavelength emitted from a light source 2 described later and having a wavelength to be transmitted through the liquid X to be detected for concentration, and in the present embodiment, light having a wavelength in the range of at least 200 nm to 400 nm. Therefore, for example, quartz, UV glass, or the like can be used.

The light sources 2 and 3 may emit light having a wide range of wavelengths (light including from ultraviolet light to infrared light), but the first light source 2 has a wavelength in the range of 270 nm to 330 nm. The light source 3 of 2 has a wavelength in the range of 350 nm to 400 nm. This means that both nitrate and nitrite ions in the liquid exhibit appropriate absorbance characteristics when irradiated with light from a light source in the wavelength range of 270 nm to 330 nm, while the wavelength range of 350 nm to 400 nm. This is because only the nitrite ion in the liquid exhibits an appropriate absorption characteristic by irradiating the light of the light source from the inside. The fact that only nitrite ions exhibit absorption characteristics means that when light of the wavelength is irradiated, the transmitted light intensity does not change regardless of the presence or absence of nitrate ions.

Although two types of light sources 2 and 3 are used to irradiate light in different wavelength bands, a single light source can be used and the splitter can irradiate both detectors. , Irradiation light to different detectors may be emitted sequentially depending on the rotation filter. As these light sources, a deuterium lamp (D2 lamp), a UV-LED (ultraviolet LED), a Deep UV-LED (deep ultraviolet LED) and the like can be used, but the light source is not limited thereto.

The light sources 2 and 3 that emit light of these various wavelengths are provided on the outside of one of the wall surfaces 11 constituting the inspection area constituent unit 1 and are installed so as to irradiate the light toward the wall surface 11. .. With such a configuration, the light emitted from the light source 2 passes through the wall surface 11 and is applied to the concentration detection target liquid X. When light is transmitted through the liquid X to be detected in concentration, it is transmitted through another wall surface 12 located on the opposite side and reaches the outside thereof.

Therefore, the photodetectors 4 and 5 are provided on the wall surface 12 on the opposite side. The light detection units 4 and 5 are provided with light receiving units 41 and 51, respectively, and a photodetector (photodetector) is used as these light receiving units 41 and 51 to electrically convert the intensity of the received light. can do. The light intensity data detected by these light receiving units 41 and 51 is transmitted to a control unit (not shown) via the transmission cables 42 and 52. As the photodetector, for example, there is a photodiode that uses a pn junction of a semiconductor.

In the present embodiment, the two photodetectors 4 and 5 are configured to detect the irradiation light (transmitted light) from different light sources, but the two photodetectors may be configured by a single photodetector. In this case, the two types of transmitted light are detected alternately. For example, two light sources 2 and 3 can be used, and the transmitted light of each can be detected by a time difference. Further, when there is a single light source, there may be a method in which the light source is separated into two types by a spectroscope or the like and these are detected alternately.

The control unit functions as a conversion unit for converting the absorbance into an ion concentration, and the absorbance of the liquid X whose concentration is to be detected from the light intensity (transmitted light intensity) measured by the light detection units 4 and 5 described above. Is calculated, and the concentrations of nitrate ion and nitrite ion are calculated by comparing the absorbances of each specific wavelength.

Since the embodiment of the present invention relating to the nitrate ion concentration detecting apparatus has the above-described configuration, it is possible to perform continuous measurement while continuously flowing the liquid X whose concentration is to be detected into the inspection region constituent unit 1. can. As a result, it is possible to detect the concentration of the nitrate ion-containing liquid that has already been prepared, and gradually add (generate) nitrate ion while detecting whether or not the desired concentration has been reached. It can be used to increase the concentration. This is particularly effective when producing a large amount of nitrate ion-containing liquid.

<Nitrate ion concentration detection method>
Next, a method for detecting the nitrate ion concentration will be described. It is well known that nitrate ion and nitrite ion exhibit different absorption characteristics depending on the wavelength of transmitted light. That is, as described above, for example, when light having a wavelength of 350 nm to 400 nm is transmitted, the absorption characteristic for nitrate ion (NO _3- ) is not shown, but the absorption characteristic for nitrite ion _{(NO 2-} ^{) is} exhibited. Further, when light having a wavelength of 270 nm to 330 nm is transmitted, some of them exhibit absorption characteristics for both ions (NO _3- ^, NO _2- ⁾ . As described above, the change in absorbance at different wavelengths is shown in FIG. 2 (a).

In such a configuration, by irradiating the light of the first light source 2, the transmitted light intensity in a state of being absorbed by both nitrate ion (NO _3- ^{) and} nitrite ion (NO _2- ) can be obtained. It can be measured, and by irradiating with the light of the second light source 3, the transmitted light intensity in a state of being absorbed only by nitrite ion (NO _2- ⁾ can be measured. At this time, since light of different wavelengths is irradiated, the absorbance of the liquid X to be detected for concentration is different, and it is not possible to simply compare the measured values of the two. Therefore, the absorbance of the nitrite ion (NO ^2- ) is calculated from the transmitted light intensity measured when the light of the _{second light source is irradiated, and further, the nitrite ion (NO 2- )} ^{corresponding} to the absorbance is calculated. Calculate the concentration. Next, the absorbance is calculated from the transmitted light intensity measured when the light of the first light source is irradiated, and the difference from the absorbance at the calculated concentration of the nitrite ion (NO _2- ⁾ is calculated. The difference is used to identify the concentration of nitrate ion (NO _3- ⁾ .

For example, as shown in FIG. 2A, a test solution containing only nitrate ion (NO _3- ) in pure water, and nitrate ion (NO _3- ⁾ and nitrite ion (NO ^{2- )} _were contained. For the test solution, an LED that irradiates light with a wavelength of 310 nm (measured value 309.4 nm) is used as the first light source 2, and light with a wavelength of 355 mm (measured value 357.8 nm) is radiated as the second light source 3. When an LED is used, both light sources 2 and 3 show different absorption characteristics. The concentration can be calculated from the absorbance by using Lambert-Beer's law, and by producing a calibration curve, it is possible to perform conversion based on the calibration curve.

Note that AT1 in FIG. 2A is the total absorbance at a wavelength of 310 nm, of which _{A1 indicates} the absorbance due to nitrate ion alone and _A2 indicates the absorbance due to _only nitrate ion. As a result, the following relational expression holds.

Further, AT2 in FIG. 2A is the _total absorbance at a wavelength of 355 nm _, and when _A3 is the absorbance by nitrate ion and A4 is the absorbance by nitrite ion _, A3 = 0. The relational expression is as follows.

Therefore, the preparation of the calibration curve will be described next. The calibration curve will be prepared based on Lambert-Beer's law. Lambert-Beer's law is that the absorption path of a solution is proportional to the concentration of the solution and the optical path length, as shown in the following equation.

Therefore, in order to calculate the molar concentration (c) from the above formula, the following formula can be used.

When converting from the above formula to the concentration of the liquid actually used, it can be calculated by liquid concentration (mg / L) = substance amount (g / mol) × molar concentration (mol / L) / 1000.

By the way, in order to prepare a calibration curve, it is necessary to measure the relationship between the absorbance and the concentration when the concentrations of nitrate ion (NO _3- ^{) and} nitrite ion (NO _2- ) are different. Therefore, the wavelengths of the two types of irradiation light were specified, and the absorbance of each concentration was measured for solutions having different ion concentrations. The two types of wavelengths are the same as described above. The relationship between the absorbance and the concentration of light of these wavelengths is shown in FIG. 2 (b). The diagram shown on the graph as _AT1 shows only the absorbance and the concentration of nitric acid in both ions mixed at a constant ratio. Note that FIG. 2 (b) diagram A ₁ shows the relationship of nitrate ion (A ₁ ) when irradiated with a light source of 310 nm, and diagram A ₄ shows the relationship of nitrate ion when irradiated with a light source of 355 nm. Shows the relationship. All of them are based on the results of measuring the absorbance of each liquid using a liquid whose concentration has been adjusted in advance.

The diagram of A ₂ in FIG. 2 (b) can be obtained as follows. That is, as shown in FIG. 3A, the diagram A1 shows the relationship between the liquids containing _only nitrate ions, and the diagram _AT1 contains nitrate ions and nitrite ions in a predetermined ratio. Since the relationship between the two liquids is shown, the difference H between the two absorbances is the increase in the absorbance with the nitrite ion content.

Therefore, as shown in FIG. 3 (b), the increase H of the absorbance is converted into the concentration obtained by the diagram A4 ₍ that is, the diagram of only the nitrite ion at the wavelength 355) (the absorbance having the same concentration is obtained). By plotting), the absorbance at a wavelength of 310 nm can change. Figure A ₂ can be obtained by determining the absorbance of liquids of the same concentration ratio for different concentrations. As a result, all the calibration curves of A ₁ , A ₂ , _{AT 1} and A ₄ can be obtained.

When using these calibration curves, the absorbances at two types of wavelengths (310 nm and 355 nm) are measured simultaneously or sequentially in advance, and first, the concentration of nitrite ion obtained by FIG. A4 ₍ wavelength 355 nm) is used. The absorbance L in the diagram A ₂ (wavelength 310 nm) is obtained. Since this absorbance is due to the same concentration of nitrite ion at a wavelength of 310 nm, this is subtracted from the absorbance at 310 nm (corrected value). _The concentration on the diagram A1 at this modified value is the nitrate ion concentration obtained by subtracting the nitrite ion concentration from the detected value.

Since the embodiment of the present invention relating to the method for detecting the nitrate ion concentration has the above-mentioned configuration, first, the nitrite ion concentration is calculated and the nitrite ion concentration is calculated by simultaneously or sequentially measuring the absorbances of the two types at predetermined wavelengths. The nitrate ion concentration can be obtained by reflecting the absorbance acting by the nitrite ion concentration on the other absorbance. As a result, the nitrate ion concentration in the liquid whose concentration is to be detected can be measured instantly. Further, by continuously detecting the concentration while changing the nitrate ion concentration, the tendency of the increase can be measured, and the measurement can be continued until the desired concentration is reached. These detection methods are processed by the control unit in the above-mentioned detection device, but when based on the calibration curve, the processing method is simple and the processing time is extremely high.

By the way, the relationship between the wavelength of the irradiation light and the absorbance as described above (see FIG. 2A) is when the pH of the liquid is less than 4, and when the pH of the liquid is 4 or more, the peak of the absorbance. May change. Therefore, in the above-described embodiment, it is assumed that the pH of the liquid is less than 4, but when the discharge plasma is irradiated to increase the nitrate ion concentration as described later, the liquid is irradiated by plasma. The pH of the blood drops. Therefore, when the liquid to be detected is produced by plasma irradiation, it can be treated as having a pH of less than 4 except for a short time from the start of irradiation.

In order to confirm this, an experiment was conducted in which 1 liter of raw water having an initial pH value of 7 was irradiated with discharge plasma (using NGK PFR6B, output set voltage = 10 kV, duty ratio 25%). As a result, the pH value became less than 4 about 30 minutes after the start of irradiation of the discharge plasma, and the pH value did not increase thereafter. Further, considering that it takes several hours or more to greatly increase the nitrate ion concentration, the absorption characteristics as shown in FIG. 2A are obtained after the initial irradiation time (about 30 minutes) of the discharge plasma. It can be utilized and the ion concentration can be measured by a method as exemplified in the above embodiment.

A pH sensor may be used when the nitrate ion concentration is to be increased without irradiating the discharge plasma, or when it is necessary to confirm the change in pH due to the irradiation of the discharge plasma described above. .. In this case, it is possible to detect the ion concentration by the method described in the above embodiment while confirming that the pH of the liquid is less than 4 based on the pH value detected by the pH sensor. ..

Further, although the above-mentioned example utilizes the absorption characteristic when the pH of the liquid is less than 4, it is also possible to utilize the absorption characteristic when the pH of the liquid is 4 or more. That is, when the pH of the liquid is 4 or more, for example, when light in the band having a wavelength of about 350 nm is transmitted, only nitrite ion (NO _2- ⁾ has a property of remarkably exhibiting absorption characteristics. Therefore, by preparing a calibration curve (A ₄ ) for nitrite ions in such a case, it is possible to detect the ion concentration even in a liquid having a pH of 4 or higher. In this case, since the wavelength band of light having absorption characteristics for both nitrate ion (NO _3- ^{) and} nitrite ion (NO _2- ) may change, the calibration curve (A ₁ , A) in the wavelength band may also change. _2. It may be necessary to separately prepare _AT1 ) according to the pH. When a pH sensor is used as in the above example, the ion concentration is detected even under different conditions by appropriately selecting an appropriate one from a plurality of calibration curves based on the value detected by the pH sensor. be able to.

<Plant growth / life-prolonging agent manufacturing equipment>
Next, an embodiment of the present invention relating to an apparatus for producing a plant growth / life-prolonging agent will be described. 5 and 6 show the plant growth / life-prolonging agent manufacturing apparatus of this embodiment. Note that FIG. 5 is a perspective view of a part, and FIG. 6 is a schematic view showing an outline of the whole. As shown in these figures, this embodiment uses the above-mentioned ion concentration detection device 100, and is provided with a plasma discharge device 8 at the flow bottom 7 of the detection device 100. be. By providing the plasma discharge device 8, the flow bottom 7 functions as a nitrate ion generating unit. Further, a tank 9 is provided below these devices 100, and the discharged liquid (nitrate ion generated) flows into the tank 9 on the downstream side of the flow bottom (nitrate ion generating portion) 7. There is. The tank 9 is provided with a lifting pump 91 so that the liquid can be supplied to the liquid feeding unit 6 again. A predetermined circulation path is formed by such a configuration.

In the present embodiment, since the plasma discharge device 8 is used to generate nitrate ions, the power supply 81 is supplied to the plasma discharge device 8 and the bottom surface portion of the flow bottom (nitrate ion generation portion) 7 is supplied. The submersible electrode (made of copper, platinum, platinum-lodium, etc.) 80 is arranged in the longitudinal direction. The power supply 81 transmits a predetermined voltage / current or power to the plasma discharge device 8 via the voltage / current and power output adjustment control unit 82.

With such a configuration, the plasma discharge device (discharge electrode) 8 to which a predetermined voltage is applied irradiates the plasma toward the submerged electrode 80, and the liquid irradiated with the plasma is nitrogen in the atmosphere. Can react with to generate nitrate ions in the liquid.

The plasma discharge device 8 may be a single device or a plurality of plasma discharge devices 8, but in the present embodiment, as shown in FIG. 6, a large number of plasma discharge devices (discharge electrodes) 8 may be arranged. Is divided into multiple groups, and the timing of each operation is adjusted. That is, several (three in the figure) from the side closest to the ion concentration detection device 100 are grouped into one group (A group) 8A, and the same number of next-order groups (B group) 8B and the next group (C group). Three groups are configured as 8C. By dividing into a plurality of groups and irradiating the plasma sequentially in this way, it is possible to concentrate the discharge plasma on the flowing liquid.

In this way, in order to sequentially operate the groups 8A, 8B, and 8C, a switching circuit 83 is interposed between the power supply and the plasma discharge device 8. By controlling the switching circuit 83, for example, by setting the duty ratio as shown in FIG. 7 to 1/4 (25%), heating of the discharge electrode is suppressed by intermittent discharge instead of continuous discharge. At the same time, that is, it is possible to continuously irradiate the flowing liquid with the discharge plasma without causing thermal damage to the parts around the electrodes.

The liquid level of the liquid flowing down the lower part (nitrate ion generation part) 7 can be made constant depending on the amount of the liquid supplied to the liquid feeding part 6 or the amount of the liquid passing through the ion concentration detecting device 100. In that case, the gap X between the tip of the plasma discharge device 8 and the liquid level can be kept constant. Further, in order to generate nitrate ions, the gap is preferably about 5 mm, for example.

Further, the ion concentration detection device 100 is provided with a control unit (not shown), and this control unit is a conversion unit for converting the absorbance into an ion concentration, and particularly functions as a nitrate ion concentration conversion unit. do. Therefore, the nitrate ion concentration measuring unit is composed of an ion concentration detection device 100 and a control unit, and in the case where the ion concentration detection device 100 has a control unit in advance, the nitrate ion concentration detection device 100 is used for nitrate. The ion concentration measuring unit is configured.

The embodiments of the present invention are as described above, but the present invention is not limited to these embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, regarding the light sources 2 and 3 in the ion concentration detection device, in the above embodiment, the first light source 2 and the second light source 3 are used, but a larger number of light sources may be used. There are regions in the above two regions that show remarkable absorption characteristics for both nitrate ion (NO _3- ^{) and} nitrite ion (NO _2- ), but by using the absorbance values in many regions, nitrate This is because the accuracy of ion (NO _3- ⁾ concentration detection is guaranteed.

Further, the bottom surface portion 14 (or the bottom portion of the flow path 4) of the inspection area constituent portion 1 in the above embodiment is integrally configured with the wall surfaces 11 and 12 (configured in the figure). This is because the light of the light source 1 irradiated to the void 13 of the inspection area constituent portion 1 is not reflected by the bottom surface portion 14. As described above, it is not necessary for the bottom surface portion 14 to be made of the same material as the wall surfaces 11 and 12, and it may be made of another material, but at least a material that does not allow reflected light to enter the inside of the void 13 is used. Is required. Further, the wall surfaces 11 and 12 of the inspection area constituent unit 1 show only a configuration in which they are separately installed side by side according to the name, but they are arranged in the vertical direction (substantially with the bottom surface portion 14). The case of installing as the upper surface portion 15) is also included in the present invention. This is because the inspection area constituent unit 1 can obtain the same effect as long as the predetermined void 13 is formed.

Further, in the above embodiment, the value detected by the light detection units 4 and 5 to be transmitted to the processing unit by the transmission cables 42 and 52 is limited to such wired data transmission. In some cases, data may be transmitted wirelessly or via a public line such as an Internet line.

1 Inspection area component 2, 3 Light source 4, 5 Light detection unit 6 Liquid supply unit 7 Flow bottom (nitrate ion generation unit)
8 Plasma generator (discharge electrode)
8A Group A
8B Group B
8C Group C
11, 12 Wall surface 13 Void 14 Bottom surface 15 Top surface 41, 51 Light receiving 42, 52 Transmission cable 80 Submersible electrode 81 Power supply 82 Output adjustment control 83 Switching circuit 100 Ion concentration detector

Claims (7)

A device for producing a liquid for promoting the growth of cut flowers by using a concentration detection device for detecting the concentration of ionized nitrate ion and nitrite ion in the liquid.
A tank for storing liquid and
A lifting pump that lifts the liquid stored in the tank and causes the liquid to flow down along a predetermined circulation path.
A nitrate ion generating part that generates nitrate ions in the liquid flowing down along the circulation path, and
It is provided with a nitrate ion concentration measuring unit for measuring the nitrate ion concentration in the liquid lifted from the tank on the upstream side of the circulation path.
The nitrate ion concentration measuring unit includes the concentration detecting device and a nitrate ion concentration converting unit.
The concentration detection device is
A wall surface capable of transmitting 1% or more of light having a wavelength of at least 200 nm to 400 nm forms voids at appropriate intervals, and the inspection region constituent portion that allows the liquid to be detected for concentration to pass through or be stored in the voids.
A light source that emits light having a wavelength in the range of at least 270 nm to 330 nm and a wavelength of 350 nm to 400 nm so as to transmit the inspection region component from the outside of the wall surface of the inspection region component.
It is provided with a photodetector that detects the intensity of light emitted from the light source and transmitted through the inspection area component.
A plant growth / life-prolonging agent manufacturing device characterized by this. The concentration detection device is
Furthermore, it is equipped with a calculation unit that calculates the concentration of nitrate ion and nitrite ion of the liquid to be detected from the intensity of transmitted light at a specific wavelength.
Claim 1 is characterized in that the values of the concentrations of nitrate ion and nitrite ion are calculated by measuring the transmitted light intensity of a specific wavelength transmitted through the liquid whose concentration is to be detected in the void of the inspection region component. The plant growth / life-prolonging agent manufacturing apparatus described in 1. The light source is divided into a first light source in a wavelength region having absorption characteristics for both nitrate ion and nitrite ion and a second light source in a wavelength region having absorption characteristics only for nitrite ion. The plant growth / life-prolonging agent manufacturing apparatus according to claim 1 or 2. The plant growth / life-prolonging agent manufacturing apparatus according to claim 3, wherein the photodetector alternately detects transmitted light from the first and second light sources. The light detection unit includes a first detector that detects the intensity of light in a wavelength region having absorption characteristics for both nitrate ion and nitrate ion, and light in a wavelength region having absorption characteristics for both nitrate ion only. The plant growth / life-prolonging agent manufacturing apparatus according to claim 3, further comprising a second detector for detecting intensity. The inspection area component portion is composed of a flow path having a side wall formed by the wall surface, and is characterized in that the liquid to be detected for concentration supplied to the flow path is irradiated with light at any time. The plant growth / life-prolonging agent manufacturing apparatus according to claim 1 to 5. Any of claims 1 to 6, wherein the nitrate ion generating unit is composed of a plurality of discharge plasma irradiating means, and simultaneously or sequentially irradiates the liquid flowing along the circulation path with the discharge plasma. Plant growth / life-prolonging agent manufacturing equipment described in Crab.

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