KR102120642B1 - Three-dimensional porous membrane for seawater desalination, method for manufacturing the same, seawater desalination apparatus comprising the same and seawater desalination method using the same - Google Patents

Abstract

The present invention relates to a three-dimensional porous membrane for seawater desalination, a method for manufacturing the same, a seawater desalination device including the same, and a seawater desalination method using the same, wherein the three-dimensional porous membrane according to an embodiment of the present invention includes: a porous polymer layer; And a carbon layer comprising a carbon material formed on the porous polymer layer.

Description

THREE-DIMENSIONAL POROUS MEMBRANE FOR SEAWATER DESALINATION, METHOD FOR MANUFACTURING THE SAME, SEAWATER DESALINATION APPARATUS COMPRISING THE SAME AND SEAWATER DESALIN USING THE SAME}

The present invention relates to a three-dimensional porous membrane for seawater desalination, a method for manufacturing the same, a seawater desalination device comprising the same, and a seawater desalination method using the same.

Water is one of the most important factors in human survival. However, due to population growth and environmental pollution, the problem of water shortages in the global village has deteriorated, so securing fresh water is becoming important. In particular, countries near the equator and high-altitude regions have low water supply rates, so there are social problems due to the lack of fresh water, such as the occurrence of diseases caused by the use of contaminated wells. In order to solve these problems, it is necessary to develop a technology for desalination of sea water and salt water. However, the existing reverse osmosis membrane-based desalination technology is difficult to desalinate high concentration of brine. As a result, the cost of drinking water produced is high due to the high operating cost as it goes through several stages of water treatment. This is difficult to apply to poor areas where low-priced drinking water is needed, so it does not substantially solve the problem of drinking water shortage. Therefore, it is necessary to develop a new concept of technology that can desalination of seawater and brine in a single power-free process. This desalination technology can be a practical solution because it can produce low-cost drinking water from seawater and brine in poor areas where drinking water is needed.

Countries near the equator and high-altitude regions with severe drinking water shortages have sufficient annual seawater and saltwater for freshwater with constant high insolation. Solar-based evaporative desalination technology is a technology that can take advantage of this climatic geographical advantage, and it is possible to produce drinking water at a low cost using a single power-free water treatment process. Metal plasmons, semiconductors, carbon, and natural materials have been introduced as light absorbers for evaporation membranes. In particular, carbon-based materials are actively studied as light absorbers due to their recyclability, high light absorption, and excellent heat conversion properties, and carbon nanotubes, graphene, carbon nanoparticles, and graphene-based metal composites have been developed.

There is a need for a technique capable of maintaining an evaporation performance for a long time by reducing the ions deposited on the surface of the membrane when desalination is desalination, and the evaporation rate is high compared to the existing membrane technology.

The present invention is to solve the above problems, the object of the present invention is to provide a three-dimensional porous membrane for seawater desalination that can increase the removal rate of various ions contained in seawater.

In addition, another object of the present invention is to provide a method for producing a three-dimensional porous membrane for seawater desalination.

In addition, another object of the present invention is to provide a seawater desalination device including a three-dimensional porous membrane capable of continuously and smoothly desalination from seawater.

In addition, another object of the present invention is to provide a method for desalination of seawater using a three-dimensional porous membrane capable of desalination of seawater in a non-powered, environmentally friendly and economical manner.

However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

One aspect of the present invention, a porous polymer layer; It provides a three-dimensional porous membrane for seawater desalination, including; and a carbon layer comprising a carbon material formed on the porous polymer layer.

According to one embodiment, the porous polymer layer is polydimethylsiloxane (Polydimethylsiloxane; PDMS), polycarbonate (PC), polyethylene naphthalate (PEN), polynorbornene (Polynorbornene; PN), polyacrylic Polyacrylate, Polyvinyl alcohol (PVA), Polyimide (PI), Polyethylene terephthalate (PET), Polyethersulfone (PES), Polystyrene (PS), Polypropylene (PP), Polyethylene (PE), Polyvinylchloride (PVC), Polyamide (PA), Polybutyleneterephthalate (PBT) and Polymethacrylate (Polymethyl methacrylate) ; PMMA) may include at least one selected from the group consisting of.

According to one embodiment, the carbon layer may be a sugar-derived carbon material coated on the pore network of the porous polymer layer.

According to one embodiment, the pores of the porous polymer layer may be 100 μm to 500 μm.

According to one embodiment, the lower surface of the porous polymer layer may be a hydrophilic surface.

According to one embodiment, the hydrophilic surface may be plasma-treated.

According to one embodiment, the plasma treatment may be oxygen plasma treatment.

Another aspect of the present invention, forming a structure using sugar; Adsorbing a polymer to the structure; Forming a porous membrane by dissolving the sugar contained in the structure; Carbonizing the top of the porous membrane; And Plasma treatment of the lower carbonized porous membrane; provides a method for producing a three-dimensional porous membrane for seawater desalination.

Another aspect of the present invention, the three-dimensional porous membrane for desalination of the seawater is disposed on the seawater, the polymer layer is facing; A top plate through which the water vapor evaporated and discharged through the carbon layer of the membrane condenses through the membrane; And a fresh water storage unit in which water vapor condensed on the upper panel is collected. The upper panel is formed to be inclined in the direction of the fresh water storage unit.

According to one embodiment, the top plate may be light transmissive.

According to one embodiment, the seawater desalination device may be non-powered.

According to one embodiment, the seawater desalination device may be that the precipitation ions in seawater are desorbed due to gravity below the porous polymer layer.

Another aspect of the present invention, as a seawater desalination method using the above seawater desalination device, in a matte condition, the deposition ions formed on the top of the membrane are desorbed and discharged into the seawater through the pores of the three-dimensional porous membrane for seawater desalination. It provides a method for desalination of seawater.

According to one embodiment, the size of the pores may be controlled to control desorption and discharge of precipitated ions.

According to one embodiment, it may be to include recovering the precipitated ions.

The 3D porous membrane for seawater desalination according to an embodiment of the present invention has a very high evaporation performance compared to a conventional evaporation membrane method. In addition, it is possible to maintain high evaporation performance over a long period of time by reducing or removing ion precipitation generated on the evaporation surface during desalination of seawater. In addition, it is possible to reduce the cost of replacing and managing the membrane due to reduced membrane performance.

The method for manufacturing a three-dimensional porous membrane according to an embodiment of the present invention can manufacture a membrane having high evaporation performance, which is made of a simple process and a low-cost material through a very simple process. Accordingly, it is possible to manufacture a three-dimensional porous membrane for evaporation on an industrial scale, and continuously and smoothly desalination from seawater and brine to produce low-cost drinking water.

The seawater desalination device according to an embodiment of the present invention can utilize climate and geographic advantages by using solar-based evaporative desalination technology, and uses solar energy to evaporate seawater and brine to make the environment-friendly, non-powered desalination process Can be economically desalination. In addition, it is possible to reduce or remove ion precipitation occurring on the evaporation surface during fresh water of seawater or brine to maintain high evaporation performance for a long period of time, thereby reducing the cost of membrane replacement and management due to reduced membrane performance.

The seawater desalination method using the seawater desalination device according to an embodiment of the present invention can minimize the possibility of membrane degradation caused by the phenomenon of membrane pore clogging or membrane pore size reduction. In addition, since excellent desalination treatment flow rate can be secured, continuous and smooth desalination from seawater and salt water is possible to produce low-cost drinking water.

1 is a perspective view of a three-dimensional porous membrane for seawater desalination according to one embodiment of the present invention.
Figure 2 is a flow chart illustrating a method of manufacturing a three-dimensional porous membrane for seawater desalination according to an embodiment of the present invention.
Figure 4 (a) is a photograph showing a three-dimensional porous membrane manufacturing process for seawater desalination according to an embodiment of the present invention, Figure 4 (b) is the chemical structure of sugar.
FIG. 5(A) is a photograph of a carbonized 3D PDMS sponge membrane prepared according to an embodiment of the present invention, and the left of FIG. 5(B) is a PDMS sponge photo coated with a carbonized carbon layer, The right side of FIG. 5B is a photograph of a PDMS sponge without a carbonized layer.
FIG. 6(A) is a photograph when light is irradiated after the carbonized PDMS sponge membrane according to an embodiment of the present invention is floated on water.
6(B) is a graph showing the rate of mass change according to light irradiation when the membrane according to the embodiment of the present invention is used and not used.
6(C) is a graph showing the rate of change in temperature, humidity, and relative humidity according to light irradiation when the membrane according to the embodiment of the present invention is used.
6D is a picture taken with the infrared thermal imaging camera of FIG. 6A.
6(E) is a graph showing the surface temperature according to the light absorption time of the membrane according to the embodiment of the present invention.
7A is a photo of a solar simulator of the present invention.
7B is a graph showing the mass change of carbonized PDMS membrane after irradiating artificial sunlight according to an embodiment of the present invention.
7(C) is a graph showing the evaporation rate of carbonized PDMS membranes when irradiated with sunlight of various intensities according to an embodiment of the present invention.
7(D) is a view showing a change in ion conductivity after evaporation of brine according to an embodiment of the present invention.
The left side of Figure 8 (A) is a carbonized PDMS membrane photograph of a microporous structure coated with polyvinyl alcohol (PVA) according to an embodiment of the present invention, and the right side is an oxygen plasma treated macroporous ( This is a macroporous structure of carbonized PDMS membrane.
According to an embodiment of the present invention of FIG. 8(B), the left is a photograph showing the amount of ion precipitation of a carbonized PDMS membrane having a microporous structure coated with PVA, and the right is a macroporous treated with oxygen plasma. This is a photograph showing the amount of ion precipitation of a carbonized PDMS membrane with a (macroporous) structure.
Figure 8 (C) is a macroporous carbonized PDMS membrane surface treated with oxygen plasma in accordance with an embodiment of the present invention in the brine and irradiated with light to encompass the generation and behavior of the ion depositing layer and the surface of the membrane This is an X-ray image of the accelerator 6c biomedical imaging beamline.
9A is an X-ray photograph of the ion precipitation layer of the membrane with or without light irradiation according to an embodiment of the present invention.
FIG. 9(B) is an X-ray photograph showing changes in microbubbles with time inside the membrane in FIG. 9(A).
9(C) is an X-ray photograph of the ion precipitation layer of the membrane made of carbonized wood of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, various changes may be made to the embodiments, and the scope of the patent application right is not limited or limited by these embodiments. It should be understood that all modifications, equivalents, or substitutes for the embodiments are included in the scope of rights.

The terms used in the examples are used for illustrative purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "include" or "have" are intended to indicate the presence of features, numbers, steps, actions, components, parts or combinations thereof described herein, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the embodiment belongs. Terms, such as those defined in a commonly used dictionary, should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are assigned to the same components regardless of reference numerals, and redundant descriptions thereof will be omitted. In describing the embodiments, when it is determined that detailed descriptions of related known technologies may unnecessarily obscure the subject matter of the embodiments, detailed descriptions thereof will be omitted.

Hereinafter, a three-dimensional porous membrane for desalination of the present invention, a method for manufacturing the same, a seawater desalination device including the same, and a seawater desalination method using the same will be described in detail with reference to examples and drawings. However, the present invention is not limited to these examples and drawings.

One aspect of the present invention, a porous polymer layer; It provides a three-dimensional porous membrane for seawater desalination, including; and a carbon layer comprising a carbon material formed on the porous polymer layer.

The 3D porous membrane for seawater desalination according to an embodiment of the present invention has a very high evaporation performance compared to a conventional evaporation membrane method. In addition, it is possible to maintain high evaporation performance over a long period of time by reducing or removing ion precipitation generated on the evaporation surface during desalination of seawater. In addition, it is possible to reduce the cost of replacing and managing the membrane due to reduced membrane performance.

1 is a perspective view of a three-dimensional porous membrane for seawater desalination according to one embodiment of the present invention. Referring to FIG. 1, a three-dimensional porous membrane 100 for seawater desalination according to an embodiment of the present invention includes a porous polymer layer 110 and a carbon layer 120.

According to one embodiment, the porous polymer layer 110, polydimethylsiloxane (Polydimethylsiloxane; PDMS), polycarbonate (Polycarbonate; PC), polyethylene naphthalate (Polyethylene naphthalate; PEN), polynorbornene (Polynorbornene; PN) , Polyacrylate, Polyvinyl alcohol (PVA), Polyimide (PI), Polyethylene terephthalate (PET), Polyethersulfone (PES), Polystyrene; PS), Polypropylene (PP), Polyethylene (PE), Polyvinylchloride (PVC), Polyamide (PA), Polybutyleneterephthalate (PBT) and Polymethacrylate It may include at least one selected from the group consisting of (Polymethyl methacrylate; PMMA).

According to one embodiment, the carbon layer 120 may be a sugar-derived carbon material coated on the pore network of the porous polymer layer 110. The porous polymer layer 110 is formed of a plurality of pores, and may be a structure that is connected to each other up, down, left, and right through a point contact, line contact, or surface contact between the pores to form a network. The network structure can enhance the ability to absorb liquid as an absorbent and maximize space. The carbon layer 120 may be coated with sugar-derived carbon materials on the pore networks of the porous polymer layers 110 connected to each other up, down, left, and right.

According to one embodiment, the pores of the porous polymer layer 110 may be 100 μm to 500 μm. The pore size should be such that the ionic crystal layers deposited on the evaporation surface when the water passes and the brine evaporates can easily pass down to the bottom of the membrane after being detached from the surface. When the pores of the porous polymer layer 110 are less than 100 μm, even if the ion crystals deposited on the evaporation surface are detached from the membrane surface, the detached ion precipitation layers do not pass through the pores and are not discharged to the bottom of the membrane and remain on the evaporation surface. There is a problem that it is difficult to reduce or remove precipitated ions, and if it is more than 500 μm, precipitated ions are easily discharged through the membrane after desorption, but there is a problem that water transport inside the membrane is weakened due to weak capillary force.

According to one embodiment, the lower surface of the porous polymer layer 110 may be a hydrophilic surface. The lower surface of the porous polymer layer 110 means all surfaces under the porous polymer layer 110. The lower surface of the porous polymer layer 110 is made of a hydrophilic surface, and a large amount of seawater can be impregnated into the pores of the lower portion of the porous polymer layer 110. Accordingly, the hydrophilic surface can smoothly transport water to the surface of the porous polymer layer 110 by increasing the water permeability of seawater.

According to one embodiment, the hydrophilic surface may be plasma-treated. The plasma treatment method is a method of modifying the surface by exposing the surface of the lower surface of the porous polymer layer 110 to a partially ionized gas in a plasma state. It also has the advantage of being able to treat the membrane itself without damage and large changes in its physical properties, and that it has fewer contaminants.

According to one embodiment, the plasma treatment may be oxygen plasma treatment. By using oxygen plasma treatment, structural properties of the superhydrophilic surface and microporosity of the three-dimensional porous membrane can be used to reduce the precipitation of ions that continuously accumulate on the evaporation surface, thereby enhancing durability. When the bottom surface of the porous polymer layer 110 is submerged in sea water and sucks up sea water, ions may be filtered while the sea water passes through the three-dimensional porous membrane.

Another aspect of the present invention, forming a structure using sugar; Adsorbing a polymer to the structure; Forming a porous membrane by dissolving the sugar contained in the structure; Carbonizing the top of the porous membrane; And Plasma treatment of the lower carbonized porous membrane; provides a method for producing a three-dimensional porous membrane for seawater desalination.

The method for manufacturing a three-dimensional porous membrane according to an embodiment of the present invention can manufacture a membrane having high evaporation performance, which is made of a simple process and a low-cost material through a very simple process. Accordingly, it is possible to manufacture a three-dimensional porous membrane for evaporation on an industrial scale, and continuously and smoothly desalination from seawater and brine to produce low-cost drinking water.

Figure 2 is a flow chart illustrating a method of manufacturing a three-dimensional porous membrane for seawater desalination according to an embodiment of the present invention. Referring to Figure 2, the method of manufacturing an electrode active material according to an embodiment of the present invention, the structure forming step 210, the polymer adsorption step 220, the porous membrane forming step 230, the membrane upper carbonization step ( 240) and a plasma treatment step 250 under the membrane.

According to one embodiment, the structure forming step 210 may be to form a structure using sugar. The porous structure is formed in advance using sugar.

According to one embodiment, the polymer adsorption step 220 to the structure may be to adsorb the polymer to the structure. Pour the polymer solution into the sugar template, which is the previously prepared structure. For example, air bubbles inside the sugar template may be removed from the vacuum chamber and the inside of the sugar template may be filled with a polymer. When the polymer is adsorbed on the sugar structure corresponding to the formwork, a porous sponge-like polymer may be formed according to the structure of sugar. Then, the polymer inside the sugar template may be hardened.

According to one embodiment, the forming of the porous membrane 230 may be to form a porous membrane by melting sugar contained in the structure. For example, by dissolving sugar with water at 60 ° C. it is possible to prepare a polymer sponge without sugar. At this time, a sponge-shaped porous membrane corresponding to the reverse phase of sugar may be formed.

According to one embodiment, the membrane upper carbonization step 240 may be to carbonize the upper portion of the porous membrane. When the upper portion of the sponge polymer is heated together with sugar, for example, at 200°C to 400°C, the sugar is decomposed into carbon, and the top of the polymer sponge is carbonized.

According to one embodiment, the plasma processing step 250 under the membrane may be plasma processing the carbonized porous membrane underneath. The plasma may be surface treated with, for example, oxygen plasma to produce a three-dimensional porous membrane.

Another aspect of the present invention, the three-dimensional porous membrane for desalination of the seawater is disposed on the seawater, the polymer layer is facing; A top plate through which the water vapor evaporated and discharged through the carbon layer of the membrane condenses through the membrane; And a fresh water storage unit in which water vapor condensed on the upper panel is collected. The upper panel is formed to be inclined in the direction of the fresh water storage unit.

3 is a conceptual diagram of evaporation and desalination technology of seawater and brine using a seawater desalination device according to an embodiment of the present invention. Referring to FIG. 3, the porous seawater desalination includes a three-dimensional porous membrane 100, a top plate 310, and a freshwater storage unit 320.

According to one embodiment, the porous seawater desalination 3D porous membrane 100 may be disposed on the seawater, the porous polymer layer 110 is facing. The carbonized three-dimensional porous membrane 100 is floated on sea water and brine, and the surface of the membrane is exposed to sunlight to evaporate water that has risen to the surface through a porous structure such as a sponge of the membrane.

According to one embodiment, the top plate 310 may be that water vapor that is evaporated and discharged through the carbon layer 120 of the membrane through the membrane 100 is condensed. The top plate 310 is inclined.

According to an embodiment, the top plate 310 may be light transmissive. Accordingly, seawater may be rapidly evaporated by sunlight.

According to one embodiment, the fresh water storage unit 320 may be that water vapor condensed on the top plate 310 is collected. The water vapor evaporated by the inclined top plate 310 is condensed to collect fresh water (purified water) to the fresh water storage unit 320 using gravity.

According to one embodiment, the seawater desalination device may be non-powered. Solar-based evaporative desalination technology can utilize climatic and geographic advantages, and it can be economically desalination by using eco-friendly non-powered desalination process by evaporating seawater and salt water using sunlight. In addition, it is possible to reduce or remove ion precipitation occurring on the evaporation surface during fresh water of seawater or brine to maintain high evaporation performance for a long period of time, thereby reducing the cost of membrane replacement and management due to reduced membrane performance.

According to one embodiment, the seawater desalination device may be that the precipitation ions in seawater are desorbed due to gravity below the porous polymer layer. Therefore, it is possible to minimize the phenomenon of clogging of pores in the membrane or a reduction in the size of the pores.

Another aspect of the present invention, as a seawater desalination method using the above seawater desalination device, in a matte condition, the deposition ions formed on the top of the membrane are desorbed and discharged into the seawater through the pores of the three-dimensional porous membrane for seawater desalination. It provides a method for desalination of seawater.

The seawater desalination method using the seawater desalination device according to an embodiment of the present invention can minimize the possibility of membrane degradation caused by the phenomenon of membrane pore clogging or membrane pore size reduction. In addition, since excellent desalination treatment flow rate can be secured, continuous and smooth desalination from seawater and salt water is possible to produce low-cost drinking water.

According to one embodiment, the size of the pores may be controlled to control desorption and discharge of precipitated ions. By controlling the size of the pores of the three-dimensional porous membrane, precipitation ions may be attached or detached.

According to one embodiment, it may be to include recovering the precipitated ions. Under matte conditions (when there is no sunlight), precipitated ions can be desorbed and discharged into seawater through the pores of the three-dimensional porous membrane. Therefore, the seawater desalination method according to an embodiment of the present invention is environmentally friendly and economically capable of desalination of seawater and brine.

Hereinafter, the present invention will be described in detail with reference to the following examples and comparative examples. However, the technical spirit of the present invention is not limited or limited thereby.

Manufacturing process of carbonized 3D polydimethylsiloxane (PDMS) sponge membrane

The three-dimensional porous membrane for seawater desalination using carbonized three-dimensional polydimethylsiloxane (PDMS) can be easily manufactured with inexpensive materials.

Figure 4 (a) is a photograph showing a three-dimensional porous membrane manufacturing process for seawater desalination according to an embodiment of the present invention. Fig. 4(b) is the chemical structure of sugar.

As shown in the left side of Figure 4 (a), a cube sugar template was prepared. The PDMS solution was then poured into the cube sugar template. Bubbles inside the sugar template were removed from the vacuum chamber, and the inside of the sugar template was filled with PDMS. Subsequently, the PDMS inside the sugar template was solidified, and the sugar was dissolved with water at 60°C. As shown in the middle photo of FIG. 4(A), a PDMS sponge with missing sugar portion was made. Subsequently, when the upper surface of the PDMS sponge is heated with sugar to a heating plate at 300° C., sugar having the chemical structure of FIG. 4B is decomposed into carbon, and the upper portion of the PDMS sponge is carbonized. Finally, the prepared membrane was surface treated with oxygen plasma to prepare a carbonized 3D PDMS sponge membrane. The manufactured 3D PDMS sponge membrane is as shown in the right picture of FIG. 4(A).

Internal structure of carbonized 3D PDMS sponge membrane

5A is a photograph of a carbonized 3D PDMS sponge membrane prepared according to an embodiment of the present invention. The upper part of this membrane is a PDMS sponge coated with a carbonized carbon layer, as shown on the left side of Fig. 5B, and the lower part of the membrane is a carbonized layer, as shown on the right side of Fig. 5B. It consists of a PDMS sponge without. The upper portion of the PDMS sponge coated with the carbonized layer is a portion that absorbs sunlight and converts it into thermal energy to evaporate. PDMS sponge at the bottom of the membrane, as shown in Figure 5 (C), has a hydrophilic surface characteristic with a porous structure to effectively water in a non-powered manner from the bottom of the membrane contained in sea water or brine to the upper carbonized layer Pull up.

Evaporation performance and temperature and humidity change of carbonized 3D PDMS sponge membrane

Figure 6 (A) is a photo when the carbonized PDMS sponge membrane according to an embodiment of the present invention is floated on water and then irradiated with light. As shown in FIG. 6(A), after the carbonized PDMS sponge membrane is floated on water, water is evaporated at a high evaporation rate upon irradiation with light.

6(B) is a graph showing the rate of mass change according to light irradiation when the membrane according to the embodiment of the present invention is used and not used. As shown in FIG. 6(B), it can be seen that when the laser having a wavelength of 532 nm having a 300 mW intensity is irradiated, the evaporation rate is 3.4 times higher than when the membrane is not used.

6(C) is a graph showing the rate of change in temperature, humidity, and relative humidity according to light irradiation when the membrane according to the embodiment of the present invention is used. Referring to FIG. 6(C), the high evaporation rate by the PDMS membrane for evaporation increased to 90% relative humidity inside the container (15 cm horizontal, 20 cm vertical, 25 cm high).

This high evaporation rate is due to the strong light absorption of the membrane carbide layer and the low thermal conductivity (0.15 W/mK) of the PDMS [Fig. 6(D), Fig. 6(E)].

6 (D) is a picture taken with the infrared thermal imaging camera of FIG. 6 (A), FIG. 6 (E) is a graph showing the surface temperature according to the light absorption time of the membrane according to an embodiment of the present invention to be. Before light irradiation (t=0s), the temperature of both the membrane and the water floating on the water show an initial temperature of about 25°C. However, upon irradiation with light (t=1s), the surface temperature at the top of the membrane rapidly rose to about 75°C, and the temperature is maintained even after 30 seconds have passed. In particular, after 30 seconds, it can be seen that the irradiated light is absorbed and the converted thermal energy is concentrated locally only on the membrane surface, because the converted thermal energy is minimized to the outside due to the low thermal conductivity of the membrane. to be. The minimization of heat loss due to the low thermal conductivity can be seen in FIG. 6(E) that the water temperature under the membrane hardly changes after 1 hour and 30 minutes of light irradiation. This is because the thermal conductivity of PDMS is very low to insulate the thermal energy absorbed and converted by the carbon layer. Consequently, minimization of heat loss allows the absorbed heat energy to be used solely for evaporation.

Accordingly, FIG. 6(D) shows that the carbonized layer of the membrane has a very high light absorption and the PDMS sponge of the membrane has a very low thermal conductivity, and these properties indicate the surface temperature of the membrane as in FIG. 6(E). It is kept high so that evaporation occurs well.

Solar-based evaporation and freshwater performance of carbonized PDMS sponge membranes

Figure 7 (A) is a photovoltaic simulation equipment (solar simulator) of the present invention, Figure 7 (B) shows the mass change of the carbonized PDMS membrane after irradiating artificial sunlight according to an embodiment of the present invention It is a graph. Referring to (B) of FIG. 7, when the carbonized PDMS membrane is floated in water and irradiated with artificial sunlight of 2 kW/m ² intensity with a solar simulator, the carbonized PDMS membrane has no membrane. The evaporation rate was 4.9 times higher than the case.

7(C) is a graph showing the evaporation rate of carbonized PDMS membranes when irradiated with sunlight of various intensities according to an embodiment of the present invention. Referring to FIG. 7(C), when irradiated with sunlight of various intensities, the carbonized PDMS membrane showed a higher evaporation rate compared to other evaporative freshwater membranes.

As a result of desalination of 3 moles of brine using a carbonized PDMS membrane, it was confirmed that the ion conductivity fell below the value of the drinking water region, so that drinking water production was possible.

7(D) is a view showing a change in ion conductivity after evaporation of brine according to an embodiment of the present invention. In the case of evaporated water, ion conductivity below the drinking water region was shown. This shows that the evaporated fresh water technology using carbonized PDMS sponge membrane can produce drinking water in a single process. However, the existing membrane-based reverse osmosis technology (hatched part) shows that the ion conductivity after fresh water does not fall below the drinking water area. This means that the reverse osmosis technology in use in the existing industry is difficult to desalination in brine in a single process and requires various pre/post treatment processes. Existing membrane-based freshwater technology (hatched part in FIG. 7(D)) does not make brine into drinking water as a single freshwater process, but several multi-step processes are included, but evaporation using a carbonized PDMS membrane according to an embodiment of the present invention The desalination technology is a single solar-based process, and was able to produce drinking water with a high ion filtering performance of 99.97% (Fig. 7(D)).

Desorption and removal of ions deposited on the membrane surface using the morphological structure of the carbonized PDMS sponge membrane and hydrophilic surface properties

When brine with a high salt concentration is evaporated from the membrane, ions in the brine of ion supersaturation precipitate on the evaporation surface of the membrane, which clogs the evaporation surface and degrades the evaporation performance, which is called fouling. The carbonized PDMS membrane has a high hydrophilicity and macroporous structure, and thus, when desalination of seawater/salt water, it showed a performance of reducing ion precipitation on the evaporation surface of the membrane. This was compared with the ion precipitation performance of a carbonized PDMS membrane having a microporous structure coated with polyvinyl alcohol (PVA).

The left side of FIG. 8(A) is a photograph of a carbonized PDMS membrane having a microporous structure coated with polyvinyl alcohol (PVA) according to an embodiment of the present invention, and the right side is an oxygen plasma treated macroporous ( This is a photo of a carbonized PDMS membrane with a macroporous structure. The left side of FIG. 8(B) is a photograph showing the ion precipitation of the carbonized PDMS membrane having a microporous structure coated with PVA according to an embodiment of the present invention, and the right side is an oxygen plasma treated macroporous This is a photograph showing the amount of ion precipitation of a carbonized PDMS membrane with a (macroporous) structure. 8(A) and 8(B), it can be seen that the amount of ion precipitation at the evaporation surface was reduced to 75% compared to the microporous membrane coated with PVA.

Figure 8 (C) is a macroporous carbonized PDMS membrane surface treated with oxygen plasma in accordance with an embodiment of the present invention in the brine and irradiated with light to encompass the generation and behavior of the ion depositing layer and the surface of the membrane This is an X-ray image of the accelerator 6c biomedical imaging beamline. Referring to (C) of FIG. 8, before light irradiation (t=0s), it shows that there is no ion precipitation due to low evaporation rate on the membrane surface. However, when light is irradiated to the top surface of the membrane, evaporation occurs rapidly on the surface of the membrane and ions in the brine are deposited on the surface of the membrane. After 10 minutes, it can be seen that a lot of ion precipitation layers (salt crystal layer, darkest black) were formed on the surface of the membrane and accumulated on the evaporation surface. However, after 50 minutes of light irradiation, it was confirmed that the ion precipitation layer (salt, yellow area) on the evaporation surface was detached from the top of the membrane and settled down by gravity. The desorbed ion precipitation layer passes through the pores of the membrane by gravity, descends to the bottom, and eventually sinks to the bottom of the container containing the water. Therefore, the carbonized PDMS membrane has a higher hydrophilicity than the PVA coating layer, and the pore size of the membrane is large, so that during the evaporation process according to light irradiation, the ion-precipitation layers are detached from the evaporation surface and can escape to the bottom of the membrane to remove precipitated ions. Show.

Desorption and removal performance of ion-precipitated layer on the evaporation surface of carbonized PDMS sponge membrane with and without light irradiation

9A is an X-ray photograph of the ion precipitation layer of the membrane with or without light irradiation according to an embodiment of the present invention. Referring to FIG. 9(A), when floating the membrane over brine and irradiating light, it can be confirmed that an ion precipitation layer was formed on the evaporation surface of the carbonized PDMS membrane. However, when the light irradiating the membrane is turned off, the ion precipitation layer on the surface of the membrane is detached and descends through the porous structure of the membrane to sink to the bottom of the container containing salt water, and it can be seen that most of the surface ion precipitation layer is removed.

FIG. 9(B) is an X-ray photograph showing changes in microbubbles over time in the membrane in FIG. 9(A). 60 minutes after turning on the light, the size of the air bubble inside the membrane increased. This means that the bubble expands due to the negative pressure inside the membrane, which increases the size. That is, when light is irradiated, the evaporation rate is high on the surface of the membrane, and a large negative pressure is generated inside the membrane due to the evaporating force pulling from the top of the membrane, and the ion-precipitating layer is attached to the evaporation surface. However, when the irradiated light is turned off, it can be confirmed that the size of the air bubble after 76 minutes is small. This indicates that the negative pressure inside the membrane that was pulling the air bubbles was reduced. This means that when the light irradiated to the membrane is turned off, evaporation decreases rapidly, and the evaporation force pulling upward from the top of the membrane decreases rapidly, and the negative pressure inside the membrane decreases rapidly. After irradiating the light again, after 94 minutes, you can see that the size of the air bubble increased due to the large negative pressure inside the membrane due to the evaporation power. Therefore, the photo of FIG. 9B shows the change in the internal sound pressure through a change in the size of the air bubble inside the membrane. When blocking the light being irradiated, a sudden decrease in the negative pressure inside the membrane occurs, which eventually desorbs the ionic precipitation layers on the evaporation surface as shown in FIG. 9(A) and sinks it down.

9(C) is an SEM photograph of the ion precipitation layer of the membrane made of carbonized wood of the present invention. Referring to (C) of FIG. 9, in the case of a membrane made of carbonized wood rather than a carbonized PDMS membrane, the ion precipitation layer removal rate on the evaporation surface was low when irradiated after light irradiation. This is because, in the case of a carbonized PDMS membrane, the evaporation rate is high, and when the light is blocked, the negative pressure is large and the ion precipitation layer is easily detached from the evaporation surface. to be. Accordingly, it can be seen that the removal performance of the precipitation layer by removing light irradiated on the carbonized PDMS membrane is higher than that of the carbonized wood membrane.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, even if the described techniques are performed in a different order than the described method, and/or the described components are combined or combined in a different form from the described method, or replaced or replaced by another component or equivalent Appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

100: 3D porous membrane for seawater desalination
110: porous polymer layer
120: carbon layer
310: top
320: fresh water storage

Claims (15)

Porous polymer layer; And
A carbon layer comprising a carbon material formed on the porous polymer layer;
Including,
The pores of the porous polymer layer is 100 ㎛ to 500 ㎛,
3D porous membrane for seawater desalination.
According to claim 1,
The porous polymer layer includes polydimethylsiloxane (PDMS), polycarbonate (PC), polyethylene naphthalate (PEN), polynorbornene (PN), polyacrylate, poly Polyvinyl alcohol (PVA), polyimide (PI), polyethylene terephthalate (PET), polyethersulfone (PES), polystyrene (PS), polypropylene (PP) ), polyethylene (PE), polyvinylchloride (PVC), polyamide (PA), polybutylene terephthalate (PBT) and polymethacrylate (Polymethyl methacrylate; PMMA) It includes at least one selected from,
3D porous membrane for seawater desalination.
According to claim 1,
The carbon layer is coated with a sugar-derived carbon material on the pore network of the porous polymer layer,
3D porous membrane for seawater desalination.
delete According to claim 1,
The lower surface of the porous polymer layer is a hydrophilic surface,
3D porous membrane for seawater desalination.
The method of claim 5,
The hydrophilic surface, plasma-treated,
3D porous membrane for seawater desalination.
The method of claim 6,
The plasma treatment is an oxygen plasma treatment,
3D porous membrane for seawater desalination.
Forming a structure using sugar;
Adsorbing a polymer to the structure;
Forming a porous membrane by dissolving the sugar contained in the structure;
Carbonizing the top of the porous membrane; And
Plasma treating the carbonized porous membrane underneath;
Containing,
Method of manufacturing a three-dimensional porous membrane for desalination of seawater of claim 1.
A three-dimensional porous membrane for desalination of seawater of claim 1 disposed on the seawater with the polymer layer facing thereon;
A top plate through which the water vapor evaporated and discharged through the carbon layer of the membrane condenses through the membrane; And
Fresh water storage unit condensing water vapor condensed on the top plate;
Including,
The top plate is formed to be inclined toward the fresh water storage unit,
Seawater desalination device.
The method of claim 9,
The top plate is light-transmitting,
Seawater desalination device.
The method of claim 9,
The seawater desalination device is a non-power,
Seawater desalination device.
The method of claim 9,
In the seawater desalination device, precipitation ions in seawater are desorbed by gravity due to the porous polymer layer.
Seawater desalination device.
As a seawater desalination method using the seawater desalination device of claim 9,
In the matte condition, the precipitated ions formed on the top of the membrane are desorbed and discharged into the seawater through the pores of the three-dimensional porous membrane for seawater desalination.
Seawater desalination method.
The method of claim 13,
By controlling the size of the pores to control the desorption and discharge of precipitated ions,
Seawater desalination method.
The method of claim 13,
Seawater desalination method comprising recovering the precipitated ions.

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