KR20200095353A - Nano-Composite media for hydroponics, and method for manufacturing same - Google Patents

Abstract

The present invention relates to a nanocomposite medium for hydroponic cultivation characterized in that a hydrogen-treated photocatalyst is coated on a porous medium. The present invention also relates to a manufacturing method thereof.

Description

Nano-composite media for hydroponics, and method for manufacturing same}

The present invention relates to a nanocomposite medium for hydroponic cultivation and a method for preparing the same, and more particularly, to a nanocomposite medium for hydroponic cultivation coated with a photocatalyst that absorbs light in the visible light region, and a method for preparing the same.

Hydroponic cultivation is a method of growing plants with water and culture, and is a crop method that is not affected by the geological environment. Vegetables and crops can be produced in large quantities using hydroponics, and small amounts of crops can be grown at home.

In a general hydroponic cultivation method, seeds or hair growth are cultivated using a synthetic material such as polyurethane on a predetermined cultivation plate, or a medium made of natural vegetable materials such as coco peat made by separating only the meat quality of palm fiber or coconut. However, among the existing medium materials, polyurethane is separated into industrial waste, which causes environmental pollution, and natural vegetable medium such as coco peat does not grow smoothly compared to synthetic medium due to water permeability and ventilation. There is.

In order to promote the growth of the natural plant medium, various types of catalysts have been studied, and among them, a method of converting light energy into a plant growth catalyst through a photocatalyst is being actively studied. As one of them, research on a medium using titanium dioxide (TiO ₂ ) as a photocatalyst is being conducted, but if only titanium dioxide (TiO ₂ ) is used as a photocatalyst, it cannot absorb visible light and only ultraviolet rays, resulting in low energy conversion efficiency. Has a drawback. On the other hand, research on a medium that improves energy conversion efficiency by doping a transition metal in titanium dioxide (TiO ₂ ) is being conducted, but the transition metal may generate harmful substances in the process of adding the metal and reduce adverse effects on the environment. There is a problem that it can be.

Accordingly, there is a need to develop a photocatalyst capable of increasing energy conversion efficiency to titanium dioxide (TiO ₂ ) without affecting the environment and a medium using the same.

Korean Patent Publication No. 10-0840750 (2008.06.16)

In order to solve the above problems, in the present invention, titanium dioxide (TiO ₂ ) can absorb light energy in the visible light region through heat treatment in a hydrogen atmosphere, and the hydrogenated titanium dioxide (TiO ₂ ) is nano An object of the present invention is to provide a nanocomposite medium for hydroponic cultivation and a method for producing the same, which is made into powder and coated on a porous medium to increase energy conversion efficiency.

One aspect of the present invention for achieving the above object relates to a nanocomposite medium for hydroponic cultivation, characterized in that a hydrotreated photocatalyst is coated on a porous medium.

More specifically, in the above aspect, the photocatalyst may be made of titanium dioxide (Ti0 ₂ ), and the hydrogenated photocatalyst may have a hydrophilic surface, or the hydrogen treatment is performed at 300°C in a hydrogen atmosphere. Can be heat-treated at a temperature of 700 ℃, or the porous medium is polyethylene terephthalate (PET), polyethylene (PE), polystyrene (PS), cellulose acetate, cellulose triacetate (cellulose triacetate), rice husk, futan , Rice husk extraction may include any one or more of cellulose and coconut husk, and the porous medium may be prepared by a phase change process.

In the above aspect, the structure of the hydrotreated photocatalyst may have a structure of any one of nanotubes, nanorods, and sol-gel nanoparticles.

In addition, another aspect of the present invention is to prepare a porous medium; Hydrotreating the photocatalytic nanopowder; And it relates to a method for producing a nanocomposite medium for hydroponic cultivation comprising the step of coating the hydrotreated photocatalyst on the porous medium.

In the other aspect, the method of preparing the porous medium may include preparing a mixed solution by dissolving a polymer in an organic solvent, and injecting the mixed solution into a nasal solution to undergo phase transition, and the photocatalytic nanopowder The manufacturing method may be hydrotreated at a temperature of 300°C to 700°C in a hydrogen atmosphere.

The nanocomposite medium for hydroponic cultivation according to the present invention has the advantage of being able to absorb light energy in the visible light region as the porous medium is coated with a hydrogenated photocatalyst, thereby increasing the energy conversion efficiency of the medium. .

1 is a flow chart illustrating a method of manufacturing a nanocomposite medium for hydroponic cultivation according to an embodiment of the present invention.
FIG. 2 is a flow chart illustrating detailed steps of coating a hydrotreated photocatalyst on a siege medium according to an embodiment of the present invention.
3 is a photograph for explaining a process of coating a photocatalyst according to an embodiment of the present invention.
4 is a photograph for explaining a process of manufacturing a porous medium according to an embodiment of the present invention.
5 is a photograph of an experiment using a TiO ₂ (P25) sample according to an embodiment of the present invention as a photocatalyst.
6 is a photograph of an experiment using a TiO ₂ sample according to an embodiment of the present invention as a photocatalyst.
7 is a photograph for explaining the microstructure of a nanocomposite medium coated with a photocatalytic nanopowder.
8 is a graph for comparing the average growth length of stems for water parsley grown by applying a nanocomposite medium prepared according to an embodiment of the present invention and water parsley grown without application.
9 is a graph for comparing the average number of buttercup roots for buttercups grown with and without applying a nanocomposite medium prepared according to an embodiment.
10 is a photograph for comparing the degree of growth of the stem and root of parsley.
11 is a graph for explaining a growing environment of water parsley grown by applying a nanocomposite medium prepared according to an embodiment.

Hereinafter, a nanocomposite medium for hydroponic cultivation according to the present invention and a method for preparing the same will be described in detail. The drawings introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below, but may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. In this case, unless there are other definitions in the technical terms and scientific terms used, they have the meanings commonly understood by those of ordinary skill in the technical field to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of known functions and configurations that may unnecessarily obscure are omitted.

One aspect of the present invention relates to a nanocomposite medium, in detail, to an organic-inorganic nanocomposite medium having pores of a predetermined size, and to a nanocomposite coated with a photocatalyst subjected to a hydrogen treatment in the pores. In the hydrotreated photocatalyst, the photocatalyst may be titanium dioxide (TiO ₂ ).

In an example of the present invention, the photocatalytic nanopowder may be provided as titanium dioxide (TiO ₂ ). In addition, the titanium dioxide (TiO ₂ ) form is one or more forms such as anodization nanotubes, hydrolysis nanotubes, hydrothermal nanorods, and sol-gel nanoparticles. It can be provided as, but is not limited to the form.

The titanium dioxide (TiO ₂ ) is a compound of titanium (Ti) and oxygen (O ₂ ), and the titanium (Ti) is very rich in resources and has an advantage in economy and marketability. In addition, it has excellent structural stability at high temperatures and is thus widely used as a photocatalyst. However, the titanium dioxide (TiO ₂ ) exhibits photocatalytic activity only in the ultraviolet region due to the wide band gap of 3.2 eV. In other words, in order for the titanium dioxide (TiO ₂ ) to absorb visible light, and furthermore, the LED illumination light emitting three colors of red, blue, and white visible light, the band gap of the titanium dioxide (TiO ₂ ) is formed through a process such as doping. The lowering process is absolutely necessary and can be done.

According to the Prior Art, but a way to make the titanium dioxide (TiO ₂₎ composite powder mixture in order to lower the band gap transition a titanium dioxide doped with a metal such as a metal (TiO ₂₎ started, the transition metal is toxic in the process of adding a metal Substances may be generated and may adversely affect the environment.

In order to improve this, the present invention applies a method of lowering the band gap of titanium dioxide (TiO ₂ ) through a heat treatment process in a hydrogen atmosphere. It is preferable that the heat treatment process is heat treated at a temperature of 300 to 700°C. As an example of the heat treatment process, a TiO ₂ (P25) photocatalyst sample is heated at a rate of 3 to 10° C. per minute for about 1 hour or more in a state where the flow rate of hydrogen is 10 to 100 sccm to be about 350 to 400° C. Lasts for a while. Thereafter, a process of annealing the sample was performed while slowly lowering the temperature until the atmosphere became less than 30°C. Hereinafter, the above-described heat treatment process will be referred to as a hydrotreating process. In addition, through this, a hydrophilic surface can be created on the photocatalyst, and the aqueous culture solution can be adsorbed/absorbed. Detailed conditions of the above-described hydrotreating process will be described later.

The photocatalytic nanopowder is coated on a porous medium. The porous medium may contain one or more organic substances or inorganic substances, and preferably contains a polymer. The polymer is from the group consisting of polyethylene terephthalate (PET), polyethylene (PE), polystyrene (PS), cellulose acetate, cellulose triacetate, rice husk, futan, rice husk extracted cellulose, and coconut shell. Can be chosen. In addition, of course, it may be provided as a mixture of any one or more of the above groups. In addition, the medium may generally have a large number of pores having a size of 1 to 100 μm, and preferably, it is appropriate to have a size of 5 μm or less.

According to an embodiment, the porous medium may be prepared through a phase inversion method. Specifically, in the porous medium, a mixed solution is prepared by dissolving the polymer in an organic solvent, and the mixed solution is injected into a non-solvent to undergo a phase inversion process.

As the organic solvent, an organic solvent generally used in the field may be applied, and preferably, polyaniline, hexane, cyclohexane, benzene, toluene, and dimethylsulfoxide An organic solvent of any one of side (DMSO), methyl pyrrolidone and methyl pentanedione may be applied.

Water, alcohols, ketones, and aromatic hydrocarbons may be used as the non-water solution. Specifically, as the cost solution, any one of aromatic hydrocarbons such as ultrapure distilled water, ion-exchanged water, methanol, ethanol, 2-propanol, methyl ethyl ketone, benzene, toluene, and xylene may be selected. It can be mixed and used.

In an example of the present invention, a conventionally known coating method may be applied as a method of coating the hydrotreated photocatalyst on the porous medium. For example, a method of coating a porous medium by immersing it in a photocatalyst solution can be applied, and the photocatalyst in the solution can be coated on the medium by immersing the porous medium in the photocatalyst dispersion liquid dispersed in water using a vacuum filtration device. I can. In addition, a stirring method or an electroplating method may be applied at a temperature of 50 to 80°C. In the present invention, a method of loading a medium is applied, but the method is not limited thereto, and a person skilled in the art can modify and apply any number of modifications based on the contents of the present invention.

As described above, the nanocomposite medium according to an aspect of the present invention is a medium coated with hydrogenated titanium dioxide (TiO ₂ ) on a porous medium, and the coated titanium dioxide (TiO ₂ ) is visible light, and furthermore, red , Blue and white It can act as a photocatalyst by absorbing LED illumination light emitting visible light in three colors.

For this, it is very important to lower the band gap through a hydrotreating process so that titanium dioxide (TiO ₂ ) can exhibit activity in the visible light region.

Referring to Figure 1, a method of manufacturing a nanocomposite medium according to an embodiment of the present invention a) preparing a porous medium; b) hydrotreating the photocatalytic nanopowder; And c) coating a hydrogenated photocatalyst on a porous medium, wherein the porous medium is coated with a nanopowder of titanium dioxide (TiO ₂ ) hydrotreated on one surface of the porous medium consisting of organic-inorganic It is a nanocomposite medium that can absorb visible light and promote the growth of crops.

First, a) preparing a porous medium may be performed, and in this case, the composition and content of each component are the same as described in the nanocomposite medium, and thus redundant descriptions are omitted.

When each component is prepared, as disclosed in FIG. 2, i) preparing a mixed solution by dissolving a polymer in an organic solvent; And ii) injecting the mixed solution into the nasal solution to perform phase transition; thereby preparing a porous medium.

Ⅰ) In the step of preparing a mixed solution by dissolving a polymer in an organic solvent, the concentration of the polymer solution in which the polymer is dissolved in the organic solvent may be 1 to 20% by weight, preferably 3 to 10% by weight. have. If a solute less than the above-described concentration range is dissolved, there is a possibility that the formation of the porous medium may be difficult, and if it is dissolved beyond the concentration range, the viscosity of the mixed solution becomes too high and the walls of the pores become thick, resulting in a decrease in porosity. This is because it can lead to. In addition, mixing of the polymer and the organic solvent is recommended to be performed at 30 to 180°C, but is not limited thereto. According to an embodiment, the mixed solution may be stirred at a rate of 200 to 600 RPM within 1 hour, and preferably at a rate of 300 to 500 RPM for 10 to 30 minutes.

Ii) In the step of injecting the mixed solution into the non-dissolving solution to phase transition, if the amount of the mixed solution increases, the dispersibility may decrease during the phase transition process, so it is important to mix the mixed solution at an appropriate ratio according to the experimental conditions and environment. . In this case, the appropriate mixing ratio may vary according to the judgment of a person skilled in the art, but it is preferable to mix in a line not exceeding 30% by weight.

According to an embodiment, it is preferable to keep the cost solution below 100°C, and specifically, it may have a temperature range of 10 to 60°C.

When the porous medium is prepared as described above, b) a step of hydrotreating the photocatalyst nanopowder may be performed, through which titanium dioxide (TiO ₂ ) of the photocatalyst may exhibit activity in the visible region.

Next, c) coating a hydrotreated photocatalyst on the porous medium may be performed. As described above, the coating method is not limited to a specific method, but a coating method commonly used in the art may be used, but in the present invention, a method of coating by supporting a porous medium in a photocatalyst solution is applied.

In an example of the present invention, a dispersion may be used by mixing the hydrogenated titanium dioxide (TiO ₂ ) in a predetermined amount of a solvent for uniform coating of the hydrotreated photocatalyst. In this case, the solvent may include water, and may further include any one or more of ethyl alcohol, methyl alcohol, and acetone. When using the dispersion, the concentration of the hydrogenated titanium dioxide (TiO ₂ ) may be 1 to 10% by weight, preferably 3 to 5% by weight.

According to an embodiment, an ultrasonic generator may be used to prepare a photocatalyst solution in which the photocatalyst is dispersed. In addition, the particle size of the photocatalyst particles can be determined by changing the ultrasonic conditions. Preferably, photocatalyst particles with a size of 10 to 20 nm can be obtained by ultrasonic treatment for about 20 minutes, and photocatalyst particles with a size of 20 to 30 nm by ultrasonic treatment for about 10 minutes, and a photocatalyst of 30 nm or more by ultrasonic treatment for about 5 minutes Particles can be obtained.

Hereinafter, an organic-inorganic nanocomposite medium for hydroponic cultivation according to the present invention and a manufacturing method according to the present invention will be described in more detail through examples. However, the following examples are only one reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

In addition, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the description herein are for the purpose of effectively describing specific embodiments and are not intended to limit the present invention. In addition, the unit of the additive not specifically described in the specification may be weight%.

1) TiO ₂ (P25) Application of photocatalyst hydrotreatment

Referring to FIG. 5, Preparation Example 1, Preparation Example 2, Preparation Example 3, and Comparative Preparation Example 1 may be defined as follows according to the heat treatment conditions of the TiO ₂ (P25) photocatalyst sample.

[Production Example 1]

The TiO ₂ (P25) photocatalyst sample was heated at 5° C. per minute for about 1 hour and 12 minutes at a flow rate of 50 sccm to reach 360° C., and this was continued for 2 hours. Thereafter, the temperature in the oven was lowered at 5° C. per minute for 1 hour and 12 minutes to reach 25° C. was performed.

[Production Example 2]

In the same photocatalyst and hydrogen flow conditions as in Preparation Example 1, heating was performed at 5°C per minute for about 2 hours and 20 minutes to reach 700°C, and this was continued for 2 hours. Thereafter, after lowering the temperature to 25° C., the mixture is heated again at 5° C. per minute for about 1 hour and 12 minutes to reach 360° C., which is maintained for 2 hours. Thereafter, a process of lowering the oven at 5°C per minute for 1 hour and 12 minutes was performed until the temperature in the oven reached 25°C.

[Production Example 3]

In the same photocatalyst and hydrogen flow conditions as in Preparation Examples 1 and 2, heating was performed at 5°C per minute for about 2 hours and 20 minutes to reach 700°C, and this was continued for 2 hours. Thereafter, a process of lowering the oven at 5°C per minute for 2 hours and 20 minutes was performed until the temperature in the oven reached 25°C.

[Comparative Preparation Example 1]

The same photocatalyst as in Preparation Examples 1 to 3 was used, but no heat treatment was performed on the photocatalyst.

2) TiO ₂ Hydrotreating application of nanotube type photocatalyst

6, Preparation Example 4, Preparation Example 5, and Comparative Preparation Example 2 may be defined as follows according to the heat treatment conditions of the TiO ₂ (P25) photocatalyst sample.

[Production Example 4]

The TiO ₂ photocatalyst sample was heated at 5° C. per minute for about 1 hour and 12 minutes at a flow rate of 50 sccm to reach 360° C., and this was continued for 2 hours. After that, the temperature in the oven was lowered at 25°C per minute for 15 minutes to reach 25°C.

[Production Example 5]

Under the same photocatalyst and hydrogen flow conditions as in Preparation Example 4, in a state where the flow rate of hydrogen is 50 sccm, heating at 5° C. per minute for about 2 hours and 20 minutes to reach 700° C., and this is maintained for 2 hours. Thereafter, a process of lowering the oven at 25°C per minute for 30 minutes was performed until the temperature in the oven reached 25°C.

[Comparative Preparation Example 2]

The same photocatalyst as in Preparation Examples 4 and 5 was used, but no heat treatment was performed on the photocatalyst.

In other words, the hydrotreating process conditions of Preparation Examples 1 to 5 and Comparative Preparation Examples 1 to 2 are shown in Table 1 below.

[Example]

Polyethylene terephthalate (PET) 22 g and polyaniline 400 mL were mixed, and the mixture was stirred at 200° C. at 400 RPM for 15 minutes to prepare a mixed solution. Thereafter, the mixed solution was dropped into ultrapure distilled water at 20° C. and heat-treated in an oven at 50° C. for 24 hours to prepare a porous medium.

Next, hydrotreating was performed through the processes of Preparation Examples 1 to 5 and Comparative Preparation Examples 1 to 2 described above, and 3 g of the hydrotreated photocatalyst was mixed with 250 mL of distilled water and ultrasonic waves of 4 MHz were injected to prepare a photocatalyst dispersion. Thereafter, the previously prepared porous medium was supported in the photocatalyst dispersion for 1 hour and heat-treated in an oven at 50° C. for 24 hours to prepare a nanocomposite medium.

[Analysis and performance evaluation]

1) SEM analysis:

Using a scanning electron microscope (SEM), the shape of the nanocomposite medium coated with the photocatalyst hydrotreated according to the conditions disclosed in Preparation Examples 1 to 5 and Comparative Preparation Examples 1 and 2 was confirmed. As a result, as shown in FIGS. 7 (c) to (d), it can be seen that the photocatalyst subjected to the hydrotreating process through the heat treatment process of Preparation Examples 1 to 5 was coated with nanopowder on the porous medium.

2) Growth rate promotion analysis:

In order to compare the difference in growth rate according to the presence or absence of hydrotreating, the experiment was conducted by dividing the parsley of the same species and size into experimental group A and experimental group B. In Experimental Group A, a medium of cocopeat material, which is commonly used as a medium for hydroponic cultivation, and a nanocomposite medium heat-treated in the process of Preparation Example 1 were mixed and used, and in Experimental Group B, the medium of cocopeat material and The nanocomposite medium prepared by the process of Comparative Preparation Example 1 without hydrogen heat treatment was mixed and used. The above-described experimental group A and experimental group B were subjected to a hydroponic cultivation experiment for 35 days. In addition, the average length of the stem and the average length of the root were measured and compared at intervals of 5 days.

Referring to FIGS. 8 to 10, it can be seen that the stems and roots of the water parsley in the experimental group A were more grown than the water parsley in the experimental group B. The above results show that hydrotreatment contributed to the acceleration of the growth rate of crops. In other words, through the hydrotreating process, the nanocomposite medium can absorb external LED illumination light, and the absorbed illumination light can be converted into an energy source and provided to crops. Through this, the crop may mean that growth is promoted by absorbing the provided energy source.

3) Growth condition analysis:

Changes in culture medium pH and electrical conductivity (EC) that affect the growth environment of crops were analyzed. Referring to FIG. 11, water parsley grown by applying the nanocomposite medium maintained a constant pH of 5.8 to 6.5 pH during growth, and the EC of the culture medium also maintained a constant level of 1400 to 1650 μS/cm. This may mean that, while the crop is grown through the nanocomposite medium, the environment in which the crop absorbs nitrogen and inorganic matter and the ion concentration of the culture medium are stably maintained within a predetermined range. Through this, it was confirmed that the nanocomposite medium can provide a cultivation environment in which crops can be stably grown.

Although the present invention has been described through the above-specified matters and limited manufacturing examples, this is only provided to help a more general understanding of the present invention, and the present invention is not limited to the above manufacturing examples, to which the present invention pertains. Those of ordinary skill in the art can make various modifications and variations from these descriptions.

Accordingly, the spirit of the present invention is limited to the described embodiments and should not be defined, and all things having equivalent or equivalent modifications to the claims as well as the claims to be described later fall within the scope of the spirit of the present invention. .

Claims (10)

Hydroponic cultivation nanocomposite medium, characterized in that the photocatalyst is coated on the porous medium. According to claim 1,
The photocatalyst is a nanocomposite medium for hydroponic cultivation, characterized in that titanium dioxide (Ti0 ₂ ). According to claim 2,
Hydroponic cultivation nanocomposite medium, characterized in that the hydrogenated photocatalyst has a hydrophilic surface. According to claim 1,
The hydrogen treatment is a nanocomposite medium for hydroponic cultivation, characterized in that the heat treatment at a temperature of 300 to 700 ℃ in a hydrogen atmosphere. According to claim 1,
The porous medium is any one or more of polyethylene terephthalate (PET), polyethylene (PE), polystyrene (PS), cellulose acetate, cellulose triacetate, rice husk, futan, rice husk extracted cellulose, and coconut shell Hydroponic cultivation nanocomposite medium comprising a. The method of claim 5,
The porous medium is a nanocomposite medium for hydroponic cultivation, characterized in that prepared by a phase change process. The method according to any one of claims 1 to 6,
The structure of the hydrogenated photocatalyst is a nanocomposite medium for hydroponic cultivation, characterized in that it has a structure of any one of nanotubes, nanorods, and sol-gel nanoparticles. Preparing a porous medium;
Hydrotreating the photocatalytic nanopowder; And
A method for producing a nanocomposite medium for hydroponic cultivation comprising the step of coating the hydrogenated photocatalyst on the porous medium. The method of claim 8,
The method of preparing the porous medium comprises dissolving a polymer in an organic solvent to prepare a mixed solution, and injecting the mixed solution into a non-solvent for phase transition. The method of claim 8,
The method for producing the photocatalytic nanopowder is a method of producing a nanocomposite medium for hydroponic cultivation, characterized in that the hydrogen treatment is performed at a temperature of 300°C to 700°C in a hydrogen atmosphere.

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