WO2018105787A1 - Ionic diode membrane containing tapered nano-pores and method for manufacturing same - Google Patents
Ionic diode membrane containing tapered nano-pores and method for manufacturing same Download PDFInfo
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- WO2018105787A1 WO2018105787A1 PCT/KR2016/014402 KR2016014402W WO2018105787A1 WO 2018105787 A1 WO2018105787 A1 WO 2018105787A1 KR 2016014402 W KR2016014402 W KR 2016014402W WO 2018105787 A1 WO2018105787 A1 WO 2018105787A1
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/12—Anodising more than once, e.g. in different baths
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/18—After-treatment, e.g. pore-sealing
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/18—After-treatment, e.g. pore-sealing
- C25D11/24—Chemical after-treatment
Definitions
- the present invention relates to an ion diode membrane having a porous structure having an inclined nano-pores integrated with ion selectivity and ion rectification characteristics, and a method of manufacturing the same, and more particularly, not only having ion selectivity but also low surface resistance.
- the present invention relates to a method for producing an ion diode membrane capable of adjusting various characteristics such as rectification characteristics and membrane resistance of the ion diode membrane.
- the ion exchange membrane is mainly used for polymer material and inorganic material, and is classified into cation exchange membrane and anion exchange membrane according to the functional group of the membrane.
- a cation exchange membrane on the surface -SO 3 - excludes the negative ions because such jinigi negatively charged functional groups, and selectively transmitting positive ions -, -COO -, -PO 3 2- , -PO 3 H -, -C 6 H 4 O.
- the anion exchange membrane has a positively charged functional group, such as -NH 3 + , -NRH 2 + , -NR 2 H + , -NR 3 + , -PR 3 + , -SR 2+ to selectively permeate the anion.
- Ion exchange membranes have traditionally been used in a variety of industries, including electrical desalination technology, production of acids and alkalis, removal of heavy metals from industrial wastewater, desalination of seawater, production of ultrapure water in the semiconductor industry, salt production in seawater, recovery of organic acids and amino acids from fermentation, etc. It has been applied in the field. However, in recent years, as the field of application is expanded beyond these existing applications, ion exchange membranes with new functions and characteristics are required.
- Ion exchange membrane is used as a key material to determine performance and cost in the fields of renewable energy sources such as capacitive seawater desalination, reverse electric dialysis power generation, fuel cell, redox flow battery, etc. Due to its film resistance, low mechanical, chemical and thermal durability, the commercialization of related industries is hindered. Since the 1980s, high-efficiency membranes have been developed by Tokuyama Corporation, Asahi Chemical, DuPont, etc., but the cost of the membrane has been reduced, but the cost and membrane resistance of the membrane are still very high to achieve economic feasibility. Therefore, there is a long demand for a next generation ion exchange membrane having a low membrane resistance, high permeation selectivity, excellent mechanical, chemical and thermal stability, and low production cost, which can replace the existing ion exchange membrane.
- the support layer does not change the passage diameter in the pore according to the depth change; And an ion diode membrane having excellent film resistance and rectification characteristics due to the high density of nanopores including a diode layer whose passage diameter changes in accordance with the depth change, and the process conditions of the anodization It is a technical object of the present invention to provide a method of manufacturing an ion diode membrane capable of controlling the rectification characteristics and the film resistance by controlling the shape.
- the ion diode membrane of the present invention is an ion diode membrane in which inclined nanopores are integrated with different diameters of the inlet and the outlet, and the nanopores include a diode layer in which the passage diameter in the pores changes with a depth change.
- the ion diode film production method of the present invention (a) preparing a metal and an electrolyte for anodization; (b) performing a second anodization in which isotropic etching by the electrolyte is performed to form an oxide serving as a diode layer of the ion diode membrane; (c) removing the metal to obtain a porous template of the oxide; And (d) removing the lower portion of the porous template to obtain a penetrated ion diode membrane.
- the manufacturing method of the present invention by controlling the process conditions of the anodic oxidation can control the form of the internal pores of the membrane to produce an ion diode membrane excellent in membrane resistance and rectification characteristics, it is possible to reduce the manufacturing cost.
- the effects of the present invention are not limited to the above-described effects, but should be understood to include all the effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.
- FIG. 1 is a schematic diagram showing various forms of one pore of an ion diode membrane according to an embodiment of the present invention.
- FIG. 2 is a schematic diagram of an ion diode film in which an inclined nanopores are integrated according to an embodiment of the present invention.
- FIG. 3 is a flowchart illustrating a process of manufacturing an ion diode film according to an embodiment of the present invention.
- FIG. 4 is a schematic diagram illustrating a method of controlling nanopores of an ion diode membrane.
- FIG. 5 is a schematic diagram showing nano-pores designed by one embodiment of the present invention.
- FIG. 6 is an electron microscope image of a diode layer fabricated by the high temperature square pulse anodization in an embodiment of the present invention.
- FIG. 7 is an electron microscope image of an ion diode membrane prepared in an embodiment of the present invention.
- FIG 9 is a graph showing the open circuit voltage and the short-circuit current of the ion diode membrane according to the embodiment of the present invention measured in seawater (500 mM NaCl) and fresh water condition (10 mM NaCl).
- the “pores with the slope” are nanopores having different diameters of the inlet and the outlet, that is, the passages in the nanopores have a shape in which the diameter changes with a change in depth, for example, as shown in FIG. 1. It means a tapered form of pores in which the diameter is larger than the outlet and the passage diameter in the pores becomes narrower.
- the “low temperature” and “high temperature” means a relative anodization process temperature
- Low temperature refers to the temperature at which the isotropic etching does not occur by the electrolyte used in the anodization process
- high temperature refers to the temperature at which the isotropic etching occurs by the electrolyte used during the anodizing process. It can be determined according to the electrolyte or production rate and form.
- the ion diode membrane of the present invention is an ion diode membrane in which inclined nanopores having a different density from each other in diameter of the inlet and the outlet are densely integrated, and the nanopores include a diode layer in which the passage diameter in the pores changes with depth change.
- the nanopores may include: a support layer having no change in the diameter of the passage in the pores according to the depth change; And a diode layer in which the passage diameter in the pores changes according to the depth change.
- the ion diode membrane of the present invention may be classified into a cationic diode membrane having a negatively charged functional group and an anion diode membrane having a positively charged functional group.
- the shape of the inclined nanopores or the distribution of positive / negative charges may be controlled.
- the shape of the nano-pores of the ion diode membrane includes a diode layer consisting of slanted pores gradually decreasing in diameter from the cylindrical pores, and may also include a support layer made of cylindrical pores having a relatively large diameter. In this structure, since the flow rate of ions is very fast, the separation rate can be improved.
- the length and diameter of the support layer, and the diameter profile (inner form of the inclined pores, ie, inclined form), depending on the length and length of the diode layer may vary.
- Nanopores with different diameters of inlet and outlet i.e., nanopores whose path diameters in the pores change (i.e., sloped) as the depth of the nanopores changes, are common nanopores (i.e., nanopores that are stretched in a straight line without slope).
- the concentration gradient due to the surface charge density hypertrophy layer is induced along the nanopore axis to show the rectification characteristics in the ion flow in the electrolyte.
- the ion diode membrane of the present invention can reduce the resistance to facilitate the flow of ions / molecules by designing a relatively short length of the small diameter (diode layer) used for separation of ions / molecules in the nano-pores.
- Inclined nanopores include a cylindrical portion (support layer) having no change in the passage inner diameter as the depth changes, and a portion where the passage inner diameter changes as the depth changes (the diode layer). do.
- Cylindrical nanopores of the support layer may be variously adjusted in length and diameter depending on the application, in some cases there may be no support layer.
- the inclined pores of the diode layer is connected to the cylindrical nanopores (support layer), the length, diameter, the shape of the inclination can be adjusted in various ways depending on the application.
- FIG. 2 is a schematic view of an inclined nanodiode integrated ion diode membrane of FIG. 1 according to one embodiment of the present invention.
- the support layer is manufactured for the purpose of mechanical durability of the ion diode membrane, and because the nanopore of the relatively large diameter is made to minimize the resistance of the membrane, thereby minimizing the decrease in the flow rate of ions.
- the inclined nanoporous diode layer imparts functionality such as ion selectivity and rectification to the ion diode membrane.
- the ion diode membrane of the present invention is an asymmetric membrane composed of the same material consisting of a diode layer (membrane layer) and a support layer having a separation function, and exhibits a higher separation speed than the symmetric membrane and is used for a long time because the clogging caused by foreign substances is suppressed. This is possible.
- the lattice constant of the ion diode film of the present invention is not particularly limited, but may be 2 to 1,000 nm, for example, 2 to 800 nm, for example, 2 to 600 nm, and may be determined by the following Equation 1 in a manufacturing process.
- the initial diameter of the nano-pores can be determined according to the type and voltage of the electrolyte, as can be seen from the experiment of the following examples.
- the nanostructure layer formed has a hexagonal structure
- the pore diameter can be adjusted after anodization through an isotropic etching process, the final diameter of the nanopores obtained by isotropic etching is larger than the initial diameter or less than the lattice constant Can be adjusted.
- anodization may proceed under various electrolytes and voltage conditions according to Equation 1, for example, 2.5 nm having a diameter of 1 nm or less in 1 M sulfuric acid or oxalic acid.
- the production of lattice constant nanopores is also possible.
- Anodization conditions of the present invention is not limited to Table 1, it can be extended to various conditions that can be porous anodization.
- the material of the ion diode film of the present invention is not particularly limited, but may be an oxide of a metal capable of forming a nanostructure by anodization, such as aluminum (Al), titanium (Ti), zirconium (Zr), and hafnium (Hf).
- a metal capable of forming a nanostructure by anodization
- Al aluminum
- Ti titanium
- Zr zirconium
- Hf hafnium
- An oxide of a metal selected from the group consisting of tantalum (Ta), niobium (Nb), and tungsten (W) and may be, for example, an anodic oxide of aluminum.
- Method for producing an ion diode membrane of the present invention (a) preparing a metal and an electrolyte for anodization; (b) performing a second anodization in which isotropic etching by the electrolyte is performed to form an oxide serving as a diode layer of the ion diode membrane; (c) removing the metal to obtain a porous template of the oxide; And (d) removing the lower portion of the porous template to obtain a penetrated ion diode membrane.
- the ion diode film production method of the present invention can be anodized.
- Anodization is one of the surface treatment techniques of metals, and has been widely used to prevent corrosion or to color metals by forming oxide films on metal surfaces, but recently, nanostructures such as nano dots, nanowires, nanotubes, nanorods, etc. It is widely known as a method of directly forming or producing a template for forming a structure. Al, Ti, Zr, Hf, Ta, Nb, W and the like are known as metals capable of forming nanostructures by such anodization.
- aluminum anodization film is easy to manufacture, and unlike other metals using fluorine ions, it is relatively safe to handle electrolytes, and it is easy to control the diameter, length, and distance (lattice constant) of nanopores for nanotechnology research. It has been used a lot.
- an electrolyte such as sulfuric acid, oxalic acid, selenic acid or phosphoric acid
- a thick porous anodized film is formed on the surface.
- This anodization film forms a porous layer in which pores with regular intervals grow from the inner metal in the vertical direction of the outer surface.
- the self-alignment of the nano pores is determined by a specific voltage and temperature depending on the electrolyte, and through the anodization under such self-aligning conditions, a nano template in which the nano pores are densely arranged can be produced.
- the anodized alumina nano-template is easy and economical to control the nano-pores, has been used in various fields as a nano-template manufacturing technology.
- the method of manufacturing an ion diode film of the present invention may further include the following steps after the step (a):
- the pre-anodization step is an anodization step by an electrolyte, and may be performed under the same voltage condition as the anodization step described later.
- the (a-1, a-2) process is performed, more aligned pores can be obtained, and as a result, ion flow rate can be improved.
- step (b) it may further comprise the following step to form a support layer.
- the method of manufacturing an ion diode film of the present invention may further include (e) surface treating the ion diode film by a method selected from the group consisting of a silanization process, a layer box assembly method, and a hydrothermal synthesis method.
- the anodized ion diode membrane can control the type and charge density of surface charges by surface treatment, and thus can be fabricated as a cation or anion exchange membrane.
- Surface treatment methods include a method of silanization using -OH of anodized oxide, layered box assembly method using charged polymer electrolyte, or hydrothermal synthesis method. Can be adjusted.
- FIG. 3 is a method of manufacturing an ion diode membrane using anodization according to an embodiment of the present invention, comprising: (a) preparing a metal (aluminum foil) and an electrolyte for anodizing; (a-1) pre-anodizing step of anodizing the metal to form an oxide on the metal surface; (a-2) selectively removing oxides from the metal; (a-3) forming an oxide serving as a support layer of the ion diode membrane by performing primary anodization in which isotropic etching by the electrolyte does not occur; (b) performing a second anodization in which isotropic etching by the electrolyte is performed to form an oxide serving as a diode layer of the ion diode membrane; (c) removing the metal to obtain a porous template of the oxide; (d) removing the lower portion of the porous template to obtain a penetrated ion diode film, and (e) surface treatment to control the surface
- the anodization process of (a-3) may be performed on the aluminum foil of (a) without performing the steps (a-1) and (a-2).
- the surface treatment of (e) can be progressed after (b) and (c) and a process.
- step (a-3) may be omitted.
- the lattice constant of the ion diode layer may be determined by adjusting the applied voltage of the anodization process according to Equation 1 below.
- the lattice constant of the nanoporous layer can be adjusted according to the type of electrolyte and the voltage applied to anodization, and the initial diameter is determined according to the electrolyte and the voltage.
- the nanostructure layer formed at this time has a hexagonal structure, and the pore diameter is adjustable after anodization through an isotropic etching process, and the final diameter of the nanoporous obtained by isotropic etching is larger than the initial diameter or smaller than the lattice constant. Can be adjusted in a range.
- the distribution of the unaligned pores generated through the pre-anodization process is arranged in a hexagonal structure, and the pore diameter is uniform.
- anodization may proceed under various electrolytes and voltage conditions according to Equation 1, for example, 2.5 M having a diameter of 1 nm or less in 1 M sulfuric acid or oxalic acid. It is also possible to produce nanoporous with nm lattice constant. Therefore, the anodization conditions of the present invention can be extended to various conditions capable of porous anodization.
- FIG. 4 is a schematic diagram illustrating a method for controlling nanopores of an ion diode membrane, wherein primary anodization (low temperature anodization) and secondary anodization (developed to control the shape of nanopores according to one embodiment of the present invention) are used.
- High temperature square pulse anodization method (a-3 and b of FIG. 3) to help understand.
- low temperature and high temperature refer to a relative anodization process temperature
- low temperature refers to a temperature at which isotropic etching does not occur by an electrolyte used during anodization
- high temperature refers to an anodization process.
- this temperature can be determined depending on the electrolyte, or the production rate and shape. For example, when using an aqueous solution of selenic acid and an aluminum metal, low temperature anodization may be performed at -10 ° C to 10 ° C, and high temperature anodization may be performed at 20 ° C to 80 ° C.
- the electrolyte and the applied voltage are determined according to the lattice constant (density) and initial pore diameter of the nanopores of the ion diode membrane.
- Figure 5 shows an example of the nanopores designed according to one embodiment of the present invention.
- the shape of the nanopores is designed for the length and diameter of the support layer, the length and diameter of the diode layer, and the profile of the slope (dividing the inclined pore diode layer into several sections).
- step (a-3) primary anodization (low temperature anodization) in which isotropic etching by an electrolyte is performed is performed to form an oxide serving as a support layer of the ion diode layer.
- the length L L of the support layer is proportional to the anodization time t L , the length L L of the support layer may be adjusted according to the anodization time.
- the diameter D L of the support layer nanoporous is almost equal to the initial diameter.
- Support layer length (L L ) oxide growth rate in primary anodization (v s ) x primary anodization time (t s )
- the oxide film growth rate is a growth rate of an oxide film including pores, and under the same voltage and electrolyte conditions, the growth rate of the oxide film is constant at the same temperature, and the growth rate increases with increasing temperature.
- step (b) secondary anodization (high temperature (square pulse) anodization) in which isotropic etching by the electrolyte is performed to form an oxide that becomes a diode layer of the ion diode film.
- the square pulse is a square pulse of 0V and the same applied voltage as the first anodization.
- 0V means a voltage at which anodization does not occur, and may be a voltage condition below an applied voltage.
- the number of cycles of the square wave is equal to the number of divisions of the diode layer.
- 4) is a schematic diagram which shows the shape of a square wave. That is, the n-cycle high-temperature square pulse anodization process forms a diode layer having n sections.
- a section of pores is formed under the support layer.
- the length L H1 and the diameter D H1 of one section formed from the first cycle are determined by the following Equations 3 and 4 from the voltage application time t H1 and the cycle time T H1 of one section. . Since secondary anodization is a condition in which isotropic etching occurs, the cylindrical pores of the support layer exposed to the electrolyte are subjected to isotropic etching. Therefore, the diameter D L of the support layer increases while the T H1 proceeds according to the equation (4).
- the length (L H2 ) and the diameter (D H2 ) of the two sections are the voltage application time (t H2 ) and the cycle time (T) of the two sections. H2 ).
- the pore diameter of the support layer and one section increases depending on T H2 .
- the length of all diode layers is the total accumulated voltage application time ( Is determined by).
- the pore diameter (D Hi ) of the i-th section is the period time accumulated from T Hi to T Hn ( Is determined from And D L and D H1 are the total accumulated cycle time ( Is determined from Using the above principle, by adjusting the cycle time and the voltage application time in each cycle of the first anodization time and the second anodization time according to the design, it is possible to freely control the nanopore shape inside the ion diode membrane. Ion diode film production is possible. In addition, since the process can be easily controlled from the program, the number of n can be very large, and precise shape control is possible therefrom.
- Length of diode layer (L H ) oxide growth rate in secondary anodization (v H ) x voltage application time (t H )
- Diameter of diode layer (D H ) etch rate (e H ) x cycle time (T H ) + initial diameter in secondary anodization
- FIG. 6 is an electron microscope image of a diode layer manufactured by a high temperature square pulse anodization in an embodiment of the present invention, and the shape control by the high temperature square pulse can be confirmed.
- step (b) After the step (b) is performed, (c) removing the metal to obtain a porous template of the oxide; And (d) removing the lower portion of the porous template to obtain a penetrated ion diode film.
- the lower portion of the porous template may be removed by wet etching or dry etching.
- the ion diode film of the present invention is not particularly limited, but the surface of the ion diode film is positively or negatively charged, and the rectification ratio may be 2 to 1000.
- the use of the ion diode membrane of the present invention is not particularly limited and includes, for example, electrical desalination technology, production of acid / alkali, removal of heavy metals from industrial wastewater, desalination of seawater, production of ultrapure water in the semiconductor industry, production of salt in seawater, It can be used for the recovery of organic acids and amino acids in the fermentation industry, the development of salt difference.
- Table 1 shows the initial diameter and the lattice constant of the pores when the electrolyte and the applied voltage were changed under the conditions described using an electron microscope.
- Aluminium foil with a smooth surface was treated with 48 V, 0.3 M aqueous solution of selenic acid as an electrolyte, and pre-anodized for 12 hours at 0 ° C.
- the oxide formed from anodization was then subjected to an aqueous solution of chromic acid (1.8 g CrO 3 + 7.1 g H 3 PO 4 (85% ) and was removed by using a mixture of distilled water (up to fill 100mL).
- chromic acid 1.8 g CrO 3 + 7.1 g H 3 PO 4 (85% )
- an ion diode layer having a conical diode layer was designed, and the length (L L ) and diameter (D L ) of the support layer were 30 ⁇ m and 90 nm, and the length (L L ) and minimum diameter (n section) of the diode layer. Diameter, D Hn ) was designed to 1.25 ⁇ m, 9nm.
- the initial diameter was 9 nm
- the growth rate (v s ) was 50 nm / min at 0 ° C.
- the growth rate (v H ) was 417 nm / min at 35 ° C.
- the etching rate e H is 0.135 nm / min.
- a support layer was fabricated by first anodizing at 0 ° C. using 48V and 0.3M aqueous solution of selenic acid, which was the same as the pre-anodization condition, for an aluminum foil having a hexagonal pattern. At this time, the anodization time was determined by Equation 2 according to the designed support layer length and proceeded for 10 hours to form a support layer of 30um. Immediately after the temperature was raised to 35 ° C, the second square pulse anodization process was carried out for 10 hours with a voltage application time of 1 second, a cycle time of 200 seconds, and n of 180 to form a diode layer of 1.25 nm. An isotropic etching of the square pulse anodization process resulted in 90 nm diameter of the support layer.
- the ion diode membrane was soaked in 30% H 2 O 2 aqueous solution for one day, and then dried.
- the surface of the anodized oxide generally has a -OH functional group, but an ion diode membrane having a -SO 3 H functional group was prepared by the silanization process and hydrogen peroxide treatment.
- the ion diode film prepared as described above was photographed with an electron microscope, and is shown in FIGS. 7A and 7B. According to the design, an ion diode film having a 1.25 ⁇ m conical diode layer and a 30 ⁇ m support layer was manufactured.
- FIG. 8 is a current-voltage curve measured by placing an ion diode membrane prepared in an embodiment of the present invention between 100 mM NaCl aqueous solution, and shows rectification characteristics of ions. Measured in 100mM NaCl aqueous solution, Figure 8a) shows the rectification characteristics of the ion diode membrane without surface treatment, and Figure 8b) shows rectification of the ion diode membrane when surface treated with -SO 3 H functional group by silanization process. Characteristics. From the process of Figure 8 it can be seen that the cation and anion diode film having a rectification ratio of about 23 and 2.5 calculated by the high concentration of 0.1M, the current amount of + 1V and -1V can be confirmed.
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Abstract
The present invention relates to an ionic diode membrane having a porous structure, which has ion selectivity and ion rectification characteristics by containing tapered nano-pores integrated therein, and a method for manufacturing the same and, more particularly, to: an ionic diode membrane which contains high-density tapered nano-pores integrated therein so as to not only have ion selectivity, but also exhibit rectification characteristics by inducing a concentration gradient along the nano-pore axis through surface charge density mismatch due to low membrane resistance; and a method for manufacturing an ionic diode membrane, which can control various properties of the ionic diode membrane, such as rectification characteristics and membrane resistance, by adjusting anodization process conditions so as to freely control the morphology of the ionic diode membrane according to designs.
Description
본 발명은 경사가 있는 나노 기공이 집적되어 이온선택성과 이온정류특성을 갖는 다공 구조의 이온 다이오드막과 그 제조방법에 관한 것으로서, 더욱 상세하게는 이온선택성을 갖는 것 뿐만 아니라 막저항이 낮아 표면전하밀도 비대층에 의한 농도구배를 나노 기공 축을 따라서 유도하여 정류특성을 갖도록 경사가 있는 나노기공이 고밀도로 집적된 이온 다이오드막과, 양극산화 공정조건을 조절하여 이온 다이오드막의 형태를 설계에 따라서 자유롭게 제어함으로써 이온 다이오드막의 정류특성이나 막저항 등의 다양한 특성을 조절할 수 있는 이온 다이오드막 제조방법에 관한 것이다. The present invention relates to an ion diode membrane having a porous structure having an inclined nano-pores integrated with ion selectivity and ion rectification characteristics, and a method of manufacturing the same, and more particularly, not only having ion selectivity but also low surface resistance. Ion diode membrane with densely integrated nanopores with inclined density to induce rectification characteristics by inducing concentration gradient due to densification layer and control the shape of ion diode membrane by adjusting anodization process conditions according to design The present invention relates to a method for producing an ion diode membrane capable of adjusting various characteristics such as rectification characteristics and membrane resistance of the ion diode membrane.
이온교환막의 시초는 1890 년에 Oswald가 이온선택성을 가진 분리막을 처음 발견하고, 1930년 Donnan에 의해 전해질 용액에서 이온교환막 내부에서 고정이온의 이온결합에 의한 대응이온의 선택적 투과현상인 Donnan exclusion 현상을 이해하는 데에서 시작하였다. 이온교환막은 고분자소재와 무기소재가 주로 사용되고 있는데, 막의 작용기에 따라 양이온교환막과 음이온교환막으로 구분된다. 양이온교환막은 표면에 -SO3
-, -COO-, -PO3
2-, -PO3H-, -C6H4O- 등 음전하 작용기를 지니기 때문에 음이온을 배제하고 양이온을 선택적으로 투과시킨다. 한편, 음이온교환막은 -NH3
+, -NRH2
+, -NR2H+, -NR3
+, -PR3
+, -SR2+ 등의 양전하 작용기를 지니고 있어 음이온을 선택적으로 투과시키게 된다. In 1890, Oswald first discovered ion-selective separators in 1890, and in 1930, Donnan discovered the Donnan exclusion phenomenon, which is the selective permeation of the counter-ion by the ion-bonding of fixed ions inside the ion-exchange membrane in the electrolyte solution. I started with understanding. The ion exchange membrane is mainly used for polymer material and inorganic material, and is classified into cation exchange membrane and anion exchange membrane according to the functional group of the membrane. A cation exchange membrane on the surface -SO 3 - excludes the negative ions because such jinigi negatively charged functional groups, and selectively transmitting positive ions -, -COO -, -PO 3 2- , -PO 3 H -, -C 6 H 4 O. On the other hand, the anion exchange membrane has a positively charged functional group, such as -NH 3 + , -NRH 2 + , -NR 2 H + , -NR 3 + , -PR 3 + , -SR 2+ to selectively permeate the anion.
이온교환막은 전통적으로 전기적 탈염기술, 산/알칼리의 생산, 산업폐수의 중금속의 제거, 해수의 담수화, 반도체 산업의 초순수의 제조, 해수에서 식염의 제조, 발효산업의 유기산 및 아미노산의 회수 등 다양한 산업분야에서 응용되어 왔다. 하지만 최근에는 이러한 기존의 응용분야에서 벗어나 그 활용분야가 확대되면서 새로운 기능 및 특성을 가진 이온교환막이 요구되고 있다. Ion exchange membranes have traditionally been used in a variety of industries, including electrical desalination technology, production of acids and alkalis, removal of heavy metals from industrial wastewater, desalination of seawater, production of ultrapure water in the semiconductor industry, salt production in seawater, recovery of organic acids and amino acids from fermentation, etc. It has been applied in the field. However, in recent years, as the field of application is expanded beyond these existing applications, ion exchange membranes with new functions and characteristics are required.
이온교환막은 최근 관심이 집중되고 있는 막축전식 해수담수화, 역전기 투석발전, 연료전지, 레독스 플로우 전지 같은 신재생에너지원 등의 분야에서 성능 및 원가를 결정하는 핵심소재로 사용되지만, 높은 가격과 막저항, 낮은 기계적, 화학적, 열적 내구성으로 인하여 관련 산업의 상용화가 저해되고 있다. 1980년대 이후 Tokuyama Corporation, Asahi Chemical, DuPont 등에서 경제성이 높은 막들이 개발되어 막의 비용이 절감되었으나, 경제성을 갖추기에는 막의 가격과 막저항이 아직도 현저하게 높은 실정이다. 따라서, 기존 이온교환막을 대체할 수 있는, 낮은 막저항, 높은 투과선택성, 우수한 기계적, 화학적, 열적 안정성, 저생산 단가의 차세대 이온교환막이 오래 전부터 요구되고 있다. Ion exchange membrane is used as a key material to determine performance and cost in the fields of renewable energy sources such as capacitive seawater desalination, reverse electric dialysis power generation, fuel cell, redox flow battery, etc. Due to its film resistance, low mechanical, chemical and thermal durability, the commercialization of related industries is hindered. Since the 1980s, high-efficiency membranes have been developed by Tokuyama Corporation, Asahi Chemical, DuPont, etc., but the cost of the membrane has been reduced, but the cost and membrane resistance of the membrane are still very high to achieve economic feasibility. Therefore, there is a long demand for a next generation ion exchange membrane having a low membrane resistance, high permeation selectivity, excellent mechanical, chemical and thermal stability, and low production cost, which can replace the existing ion exchange membrane.
이에 대한 대안으로 원뿔형태의 기공이 있는 비대칭성 이온교환막에 대한 관심이 집중되고 있다. 이러한 막은 낮은 막저항과 높은 투과선택성을 보이는 것으로 알려져 있으며, 미국의 공개특허공보 US 2003-0159985호에는 폴리이미드를 이용한 막의 제조공정이 기재된 바 있으나, 공정의 특성상 막의 기공의 밀도가 매우 작아 이온의 이동속도가 기존의 이온교환막에 비하여 매우 떨어지고, 막의 기공의 형태 제어가 불가능하여 다양한 적용이 어렵다는 단점이 있다.As an alternative, attention has been focused on asymmetric ion exchange membranes with conical pores. Such membranes are known to exhibit low membrane resistance and high permeation selectivity. US Patent Publication No. 2003-0159985 discloses a process for preparing a membrane using polyimide. However, due to the nature of the process, the pore density of the membrane is very small. The moving speed is much lower than that of the conventional ion exchange membrane, and it is difficult to control various types of pores of the membrane, so that various applications are difficult.
따라서, 기공 형태를 자유롭게 제어할 수 있는 고기공밀도의 이온 다이오드막 제조공정의 기술 개발이 요구되고 있다.Therefore, there is a demand for technology development of a high porosity ion diode membrane manufacturing process capable of freely controlling the pore shape.
본 발명은 상기와 같은 문제점을 해결하기 위하여, 깊이 변화에 따라 기공 내 통로 직경의 변화가 없는 지지층; 및 깊이 변화에 따라 기공 내 통로 직경이 변화하는 다이오드층을 포함하는 나노기공이 고밀도로 집적됨으로써 우수한 막저항 및 정류특성 등을 갖는 이온 다이오드막과, 양극산화의 공정조건을 조절함으로써 막 내부 기공의 형태를 제어하여 정류 특성과 막저항 등을 조절할 수 있는 이온 다이오드막 제조방법을 제공하는 것을 그 기술적 과제로 한다.The present invention to solve the above problems, the support layer does not change the passage diameter in the pore according to the depth change; And an ion diode membrane having excellent film resistance and rectification characteristics due to the high density of nanopores including a diode layer whose passage diameter changes in accordance with the depth change, and the process conditions of the anodization It is a technical object of the present invention to provide a method of manufacturing an ion diode membrane capable of controlling the rectification characteristics and the film resistance by controlling the shape.
본 발명의 이온 다이오드막은 입구와 출구의 직경이 서로 상이한, 경사가 있는 나노기공이 집적된 이온 다이오드막으로서, 상기 나노기공은 깊이 변화에 따라 기공 내 통로 직경이 변화하는 다이오드층을 포함한다. The ion diode membrane of the present invention is an ion diode membrane in which inclined nanopores are integrated with different diameters of the inlet and the outlet, and the nanopores include a diode layer in which the passage diameter in the pores changes with a depth change.
본 발명의 이온 다이오드막 제조방법은, (a) 양극산화를 위한 금속 및 전해질을 준비하는 단계; (b) 전해질에 의한 등방성 식각이 일어나는 2차 양극산화를 수행하여 이온 다이오드막의 다이오드층이 되는 산화물을 형성하는 단계; (c) 금속을 제거하여 산화물의 다공성 템플레이트를 얻는 단계; 및 (d) 다공성 템플레이트의 하부를 제거하여 관통된 이온 다이오드막을 얻는 단계를 포함한다.The ion diode film production method of the present invention, (a) preparing a metal and an electrolyte for anodization; (b) performing a second anodization in which isotropic etching by the electrolyte is performed to form an oxide serving as a diode layer of the ion diode membrane; (c) removing the metal to obtain a porous template of the oxide; And (d) removing the lower portion of the porous template to obtain a penetrated ion diode membrane.
본 발명의 제조방법에 따르면, 양극산화의 공정조건을 조절함으로써 막 내부 기공의 형태를 제어하여 막 저항 및 정류특성 등이 우수한 이온 다이오드막을 제조할 수 있으며, 제조 원가를 절감할 수 있다. 본 발명의 효과는 상기한 효과로 한정되는 것은 아니며, 본 발명의 상세한 설명 또는 특허청구범위에 기재된 발명의 구성으로부터 추론 가능한 모든 효과를 포함하는 것으로 이해되어야 한다.According to the manufacturing method of the present invention, by controlling the process conditions of the anodic oxidation can control the form of the internal pores of the membrane to produce an ion diode membrane excellent in membrane resistance and rectification characteristics, it is possible to reduce the manufacturing cost. The effects of the present invention are not limited to the above-described effects, but should be understood to include all the effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.
도 1은 본 발명의 일 구체예에 따른 이온 다이오드막의 기공 하나의 다양한 형태를 보여주는 모식도이다. 1 is a schematic diagram showing various forms of one pore of an ion diode membrane according to an embodiment of the present invention.
도 2는 본 발명의 일 구체예에 따른 경사가 있는 나노기공이 집적된 이온 다이오드막의 모식도이다.FIG. 2 is a schematic diagram of an ion diode film in which an inclined nanopores are integrated according to an embodiment of the present invention.
도 3은 본 발명의 일 구체예에 따른 이온 다이오드막 제조 과정을 보여주는 순서도이다. 3 is a flowchart illustrating a process of manufacturing an ion diode film according to an embodiment of the present invention.
도 4는 이온 다이오드막의 나노기공을 제어하는 방법을 나타내는 모식도이다. 4 is a schematic diagram illustrating a method of controlling nanopores of an ion diode membrane.
도 5는 본 발명의 일 구체예에 의해 설계된 나노기공을 나타내는 모식도이다.5 is a schematic diagram showing nano-pores designed by one embodiment of the present invention.
도 6은 본 발명의 실시예에서 고온 사각펄스 양극산화법으로 제작된 다이오드층의 전자현미경 이미지이다. 6 is an electron microscope image of a diode layer fabricated by the high temperature square pulse anodization in an embodiment of the present invention.
도 7은 본 발명의 실시예에서 제조된 이온 다이오드막의 전자현미경 이미지이다. 7 is an electron microscope image of an ion diode membrane prepared in an embodiment of the present invention.
도 8은 본 발명의 실시예에서 제조된 이온 다이오드막의 전류-전압곡선이다.8 is a current-voltage curve of an ion diode film prepared in an embodiment of the present invention.
도 9는 해수(500mM NaCl)와 담수조건(10mM NaCl)에서 측정된 본 발명 실시예의 이온 다이오드막의 개방전압과 단락전류를 나타내는 그래프이다.9 is a graph showing the open circuit voltage and the short-circuit current of the ion diode membrane according to the embodiment of the present invention measured in seawater (500 mM NaCl) and fresh water condition (10 mM NaCl).
이하, 도면을 참조하여 본 발명을 보다 상세하게 설명한다. 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며, 따라서 여기에서 설명하는 실시예로 한정되는 것은 아니다. 또한, 도면에서 본 발명을 명확하게 설명하기 위해서 설명과 관계없는 부분은 생략하였으며, 명세서 전체를 통하여 유사한 부분에 대해서는 유사한 도면 부호를 붙였다. Hereinafter, the present invention will be described in more detail with reference to the drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.
본 명세서에서, 어떤 부분이 다른 부분과 "연결"되어 있다고 할 때, 이는 "직접적으로 연결"되어 있는 경우뿐 아니라, 그 중간에 다른 부재를 사이에 두고 "간접적으로 연결"되어 있는 경우도 포함한다. 또한 어떤 부분이 어떤 구성요소를 "포함"한다고 할 때, 이는 특별히 반대되는 기재가 없는 한 다른 구성요소를 제외하는 것이 아니라 다른 구성요소를 더 구비할 수 있다는 것을 의미한다. In the present specification, when a part is "connected" to another part, this includes not only "directly connected" but also "indirectly connected" with another member in between. . In addition, when a part is said to "include" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.
또한, 본 명세서에서 “경사가 있는 기공”이란 입구와 출구의 직경이 상이한 나노기공, 즉 나노기공 내의 통로가 깊이 변화에 따라 직경이 변화하는 형태를 갖는 것으로서, 예를 들어 도 1과 같이 입구의 직경이 출구보다 크고 기공 내 통로 직경이 점점 좁아지는 테이퍼드(tapered) 형태의 기공을 의미하는 것이다. In addition, in the present specification, the “pores with the slope” are nanopores having different diameters of the inlet and the outlet, that is, the passages in the nanopores have a shape in which the diameter changes with a change in depth, for example, as shown in FIG. 1. It means a tapered form of pores in which the diameter is larger than the outlet and the passage diameter in the pores becomes narrower.
또한, 본 명세서에서 기재된 “1차 양극산화(저온 양극산화)” 및 “2차 양극산화(고온 양극산화)”에서 상기 “저온”과 “고온”은 상대적인 양극산화 공정온도를 의미하는 것으로서, “저온”은 양극산화 공정 중에서 사용한 전해질에 의한 등방성 식각이 일어나지 않는 조건의 온도를, “고온”은 양극산화 공정 중에 사용한 전해질에 의해 등방성 식각이 일어나는 조건의 온도를 의미하는 것으로서, 이러한 온도는 특별히 한정되는 것이 아니고 전해질에 따라, 혹은 생산속도 및 형태에 따라 결정될 수 있는 것이다. In addition, in the "first anodization (low temperature anodization)" and "secondary anodization (high temperature anodization)" described herein, the "low temperature" and "high temperature" means a relative anodization process temperature, " Low temperature ”refers to the temperature at which the isotropic etching does not occur by the electrolyte used in the anodization process, and“ high temperature ”refers to the temperature at which the isotropic etching occurs by the electrolyte used during the anodizing process. It can be determined according to the electrolyte or production rate and form.
본 발명의 이온 다이오드막은 입구와 출구의 직경이 서로 상이한, 경사가 있는 나노기공이 고밀도로 집적된 이온 다이오드막으로서, 상기 나노기공은 깊이 변화에 따라 기공 내 통로 직경이 변화하는 다이오드층을 포함하며, 예컨대 상기 나노기공은, 깊이 변화에 따라 기공 내 통로 직경의 변화가 없는 지지층; 및 깊이 변화에 따라 기공 내 통로 직경이 변화하는 다이오드층을 포함할 수 있다.The ion diode membrane of the present invention is an ion diode membrane in which inclined nanopores having a different density from each other in diameter of the inlet and the outlet are densely integrated, and the nanopores include a diode layer in which the passage diameter in the pores changes with depth change. For example, the nanopores may include: a support layer having no change in the diameter of the passage in the pores according to the depth change; And a diode layer in which the passage diameter in the pores changes according to the depth change.
본 발명의 이온 다이오드막은 음전하의 작용기를 지니고 있는 양이온 다이오드막과 양전하 작용기를 가지고 있는 음이온 다이오드막으로 분류될 수 있다. 이온 다이오드막의 특성을 조절하기 위하여 경사진 나노기공의 모양이나 양전하/음전하의 분포가 조절될 수 있다. 이온 다이오드막의 나노기공의 모양은 원통형의 기공으로부터 이어진 직경이 점차적으로 작아지는 경사진 기공으로 이루어진 다이오드층을 포함하며, 직경이 상대적으로 큰 원통형의 기공으로 이루어진 지지층도 함께 포함할 수 있다. 이러한 구조에서 이온의 흐름속도가 매우 빠르므로 분리속도의 향상이 가능하다. 용도에 따라서 지지층의 길이와 직경, 다이오드층의 길이와 길이에 따른 직경 프로파일(경사가 있는 기공의 내부 형태, 즉 경사의 형태)은 다양하게 변할 수 있다.The ion diode membrane of the present invention may be classified into a cationic diode membrane having a negatively charged functional group and an anion diode membrane having a positively charged functional group. In order to control the characteristics of the ion diode membrane, the shape of the inclined nanopores or the distribution of positive / negative charges may be controlled. The shape of the nano-pores of the ion diode membrane includes a diode layer consisting of slanted pores gradually decreasing in diameter from the cylindrical pores, and may also include a support layer made of cylindrical pores having a relatively large diameter. In this structure, since the flow rate of ions is very fast, the separation rate can be improved. Depending on the application, the length and diameter of the support layer, and the diameter profile (inner form of the inclined pores, ie, inclined form), depending on the length and length of the diode layer may vary.
입구와 출구의 직경이 상이한 나노기공, 즉 나노기공의 깊이 변화에 따라 기공 내 통로 직경이 변화하는(즉, 경사가 있는) 나노기공은 일반적인 나노기공(즉, 경사가 없는 일직선으로 펼쳐진 나노기공)과 다르게 표면전하밀도 비대층에 의한 농도구배를 나노기공 축을 따라서 유도하여 전해질 안의 이온흐름에서 정류특성을 보인다. 또한 본 발명의 이온 다이오드막은 나노기공 중에서 이온/분자의 분리에 사용되는 직경이 작은 부분(다이오드층)의 길이를 상대적으로 짧게 설계함으로써 저항을 줄여 이온/분자들의 흐름을 보다 용이하게 할 수 있다. Nanopores with different diameters of inlet and outlet, i.e., nanopores whose path diameters in the pores change (i.e., sloped) as the depth of the nanopores changes, are common nanopores (i.e., nanopores that are stretched in a straight line without slope). In contrast, the concentration gradient due to the surface charge density hypertrophy layer is induced along the nanopore axis to show the rectification characteristics in the ion flow in the electrolyte. In addition, the ion diode membrane of the present invention can reduce the resistance to facilitate the flow of ions / molecules by designing a relatively short length of the small diameter (diode layer) used for separation of ions / molecules in the nano-pores.
도 1은 본 발명의 일 구체예에 따른 경사가 있는 나노기공의 모식도이다. 경사가 있는 나노기공은, 깊이 변화에 따라 기공 내 통로 내부 직경의 변화가 없는 원통형 부분(지지층)과, 깊이 변화에 따라 통로 내부 직경이 변화하여 통로 내부가 경사를 이루는 부분(다이오드층)을 포함한다. 원통형의 나노기공인 지지층은 용도에 따라 길이와 직경이 다양하게 조절될 수 있으며, 경우에 따라서는 지지층이 존재하지 않을 수도 있다. 경사진 기공인 다이오드층은 원통형의 나노기공(지지층)과 이어져 있으며, 용도에 따라서 길이와 직경, 경사의 형태가 다양하게 조절될 수 있다. 1 is a schematic diagram of the nanopores with a slope according to an embodiment of the present invention. Inclined nanopores include a cylindrical portion (support layer) having no change in the passage inner diameter as the depth changes, and a portion where the passage inner diameter changes as the depth changes (the diode layer). do. Cylindrical nanopores of the support layer may be variously adjusted in length and diameter depending on the application, in some cases there may be no support layer. The inclined pores of the diode layer is connected to the cylindrical nanopores (support layer), the length, diameter, the shape of the inclination can be adjusted in various ways depending on the application.
도 2는 본 발명의 일 구체예에 따른 도 1의 경사가 있는 나노기공이 집적된 이온 다이오드막의 모식도이다. 지지층은 이온 다이오드막의 기계적 내구성을 목적으로 제작되며, 상대적으로 큰 직경의 나노기공으로 이루어져 막의 저항이 최소화되기 때문에, 이온의 흐름속도가 감소하는 것을 최소화시킨다. 경사가 있는 나노기공인 다이오드층은 이온 다이오드막에 이온의 선택성과 정류작용 등의 기능성을 부여한다. 또한 본 발명의 이온 다이오드막은 분리기능을 갖는 다이오드층(멤브레인층)과 지지층으로 이루어지는 동일 소재로 구성된 비대칭막으로서, 대칭막에 비하여 높은 분리속도가 나타나며, 이물질에 의한 막힘 현상이 억제되어 장시간 동안 사용이 가능하다.FIG. 2 is a schematic view of an inclined nanodiode integrated ion diode membrane of FIG. 1 according to one embodiment of the present invention. FIG. The support layer is manufactured for the purpose of mechanical durability of the ion diode membrane, and because the nanopore of the relatively large diameter is made to minimize the resistance of the membrane, thereby minimizing the decrease in the flow rate of ions. The inclined nanoporous diode layer imparts functionality such as ion selectivity and rectification to the ion diode membrane. In addition, the ion diode membrane of the present invention is an asymmetric membrane composed of the same material consisting of a diode layer (membrane layer) and a support layer having a separation function, and exhibits a higher separation speed than the symmetric membrane and is used for a long time because the clogging caused by foreign substances is suppressed. This is possible.
본 발명의 이온 다이오드막의 격자상수는 특별히 한정하지 않으나, 2~1,000 nm, 예컨대 2~800 nm, 예컨대 2~600 nm 일 수 있으며, 제조 공정에서 하기 수학식 1에 의해 결정될 수 있다.The lattice constant of the ion diode film of the present invention is not particularly limited, but may be 2 to 1,000 nm, for example, 2 to 800 nm, for example, 2 to 600 nm, and may be determined by the following Equation 1 in a manufacturing process.
[수학식 1][Equation 1]
격자상수 (nm)= 2.5 (nm/V) x U (V) Lattice constant (nm) = 2.5 (nm / V) x U (V)
(상기 식에서, U는 인가전압임.)(Where U is an applied voltage)
또한, 나노기공의 초기 직경은 하기 실시예의 실험으로부터 알 수 있는 바와 같이, 전해질의 종류와 전압에 따라 결정될 수 있다. 이때 형성되는 나노구조층은 육방정계의 구조를 가지며, 기공의 직경은 등방성 식각공정을 통하여 양극산화 후에 조절 가능하며, 등방성 식각으로 얻어진 나노기공의 최종 직경은 초기 직경보다 크거나 격자상수보다 작은 범위에서 조절될 수 있다. 본 발명의 이온 다이오드막과 같이 균일한 다공을 요구하지 않을 경우에는 상기 수학식 1에 따라서 다양한 전해질과 전압조건에서 양극산화가 진행될 수 있으며, 예컨대 1M 황산 혹은 옥살산에서는 1nm 이하의 직경을 가지는 2.5nm 격자상수의 나노기공의 제조도 가능하다. 본 발명의 양극산화 조건은 표 1에 국한되지 않고, 다공성 양극산화가 가능한 다양한 조건으로 확대될 수 있다. In addition, the initial diameter of the nano-pores can be determined according to the type and voltage of the electrolyte, as can be seen from the experiment of the following examples. At this time, the nanostructure layer formed has a hexagonal structure, the pore diameter can be adjusted after anodization through an isotropic etching process, the final diameter of the nanopores obtained by isotropic etching is larger than the initial diameter or less than the lattice constant Can be adjusted. When the uniform porosity is not required as in the ion diode membrane of the present invention, anodization may proceed under various electrolytes and voltage conditions according to Equation 1, for example, 2.5 nm having a diameter of 1 nm or less in 1 M sulfuric acid or oxalic acid. The production of lattice constant nanopores is also possible. Anodization conditions of the present invention is not limited to Table 1, it can be extended to various conditions that can be porous anodization.
본 발명의 이온 다이오드막의 재질은 특별히 한정하지 않으나 양극산화에 의해 나노 구조체를 형성할 수 있는 금속의 산화물일 수 있으며, 예컨대 알루미늄(Al), 티타늄(Ti), 지르코늄(Zr), 하프늄(Hf), 탄탈룸(Ta), 니오븀(Nb) 및 텅스텐(W)으로 구성되는 그룹으로부터 선택되는 금속의 산화물일 수 있으며, 예컨대 알루미늄의 양극산화물일 수 있다.The material of the ion diode film of the present invention is not particularly limited, but may be an oxide of a metal capable of forming a nanostructure by anodization, such as aluminum (Al), titanium (Ti), zirconium (Zr), and hafnium (Hf). , An oxide of a metal selected from the group consisting of tantalum (Ta), niobium (Nb), and tungsten (W), and may be, for example, an anodic oxide of aluminum.
본 발명의 이온 다이오드막의 제조방법은, (a) 양극산화를 위한 금속 및 전해질을 준비하는 단계; (b) 전해질에 의한 등방성 식각이 일어나는 2차 양극산화를 수행하여 이온 다이오드막의 다이오드층이 되는 산화물을 형성하는 단계; (c) 금속을 제거하여 산화물의 다공성 템플레이트를 얻는 단계; 및 (d) 다공성 템플레이트의 하부를 제거하여 관통된 이온 다이오드막을 얻는 단계를 포함한다.Method for producing an ion diode membrane of the present invention, (a) preparing a metal and an electrolyte for anodization; (b) performing a second anodization in which isotropic etching by the electrolyte is performed to form an oxide serving as a diode layer of the ion diode membrane; (c) removing the metal to obtain a porous template of the oxide; And (d) removing the lower portion of the porous template to obtain a penetrated ion diode membrane.
본 발명의 이온 다이오드막 제조방법은 양극산화법을 사용할 수 있다. 양극산화법은 금속의 표면 처리 기술의 하나로 금속 표면에 산화막을 형성하여 부식을 예방하거나, 금속을 채색하기 위하여 널리 사용되어 왔으나, 최근에는 나노 점, 나노 선, 나노 튜브, 나노 막대 등과 같은 나노 구조체를 직접 형성시키거나, 나고 구조체 형성을 위한 템플레이트를 제조하는 방법으로 크게 알려져 있다. 이러한 양극산화에 의해 나노 구조체를 형성할 수 있는 금속으로는 Al, Ti, Zr, Hf, Ta, Nb, W등이 알려져 있다. 이 중 알루미늄 양극산화막은 제조가 용이하고, 불소 이온을 사용하는 다른 금속과 달리, 전해질 취급이 비교적 안전하며, 나노 기공의 직경, 길이, 기공사이의 거리(격자상수) 제어가 쉬워 나노 기술 연구에 많이 활용되어 왔다. 알루미늄은 황산, 옥살산, 셀렌산 또는 인산 등과 같은 전해질을 포함하는 수용액에서 전기화학적으로 양극산화시키면 표면에 두꺼운 다공성 양극산화막이 형성된다. 이러한 양극산화막은 규칙적인 간격을 갖는 기공이 내부 금속으로부터 외부 표면의 수직 방향으로 성장한 다공층을 형성한다. 나노 기공의 자기 정렬은 전해액에 따라 특정한 전압과 온도에 의해 결정되며, 이러한 자기 정렬 조건에서의 양극산화를 통해 나노 기공이 조밀하게 배열된 나노 템플레이트를 제조할 수 있다. 특히 양극산화 알루미나 나노 템플레이트는 나노 기공을 제어하는 공정이 용이하고 경제적이어서, 나노 템플레이트 제조 기술로서 다양한 분야에 활용되고 있다.The ion diode film production method of the present invention can be anodized. Anodization is one of the surface treatment techniques of metals, and has been widely used to prevent corrosion or to color metals by forming oxide films on metal surfaces, but recently, nanostructures such as nano dots, nanowires, nanotubes, nanorods, etc. It is widely known as a method of directly forming or producing a template for forming a structure. Al, Ti, Zr, Hf, Ta, Nb, W and the like are known as metals capable of forming nanostructures by such anodization. Among these, aluminum anodization film is easy to manufacture, and unlike other metals using fluorine ions, it is relatively safe to handle electrolytes, and it is easy to control the diameter, length, and distance (lattice constant) of nanopores for nanotechnology research. It has been used a lot. When aluminum is electrochemically anodized in an aqueous solution containing an electrolyte such as sulfuric acid, oxalic acid, selenic acid or phosphoric acid, a thick porous anodized film is formed on the surface. This anodization film forms a porous layer in which pores with regular intervals grow from the inner metal in the vertical direction of the outer surface. The self-alignment of the nano pores is determined by a specific voltage and temperature depending on the electrolyte, and through the anodization under such self-aligning conditions, a nano template in which the nano pores are densely arranged can be produced. In particular, the anodized alumina nano-template is easy and economical to control the nano-pores, has been used in various fields as a nano-template manufacturing technology.
본 발명의 이온 다이오드막의 제조방법은, 상기 (a) 단계 후에 다음의 단계를 추가로 포함할 수 있다:The method of manufacturing an ion diode film of the present invention may further include the following steps after the step (a):
(a-1) 금속을 양극산화시켜 금속 표면에 산화물을 형성하는 사전 양극산화 단계; 및(a-1) pre-anodizing step of anodizing the metal to form an oxide on the metal surface; And
(a-2) 금속으로부터 산화물을 선택적으로 제거하는 단계.(a-2) selectively removing oxides from the metal.
상기 사전 양극산화 단계는 전해질에 의한 양극산화 단계로서, 후술하는 양극산화 단계와 동일한 전압 조건으로 수행될 수 있다. 상기 (a-1, a-2) 공정을 수행하는 경우 보다 정렬된 기공을 얻을 수 있으며, 결과적으로 이온 흐름속도를 향상시킬 수 있다.The pre-anodization step is an anodization step by an electrolyte, and may be performed under the same voltage condition as the anodization step described later. When the (a-1, a-2) process is performed, more aligned pores can be obtained, and as a result, ion flow rate can be improved.
또한, 상기 (b) 단계 전에, 다음의 단계를 추가로 포함하여 지지층을 형성할 수 있다.In addition, before the step (b), it may further comprise the following step to form a support layer.
(a-3) 전해질에 의한 등방성 식각이 일어나지 않는 1차 양극산화를 수행하여 이온 다이오드막의 지지층이 되는 산화물을 형성하는 단계.(a-3) forming an oxide serving as a support layer of the ion diode membrane by performing primary anodization in which isotropic etching by the electrolyte does not occur.
또한, 본 발명의 이온 다이오드막의 제조방법은, (e) 실란화 공정, 층상자기조립법 및 수열합성법으로 이루어진 군으로부터 선택되는 방법으로 이온 다이오드막을 표면 처리하는 단계;를 추가로 포함할 수 있다. 양극산화된 이온 다이오드막은 표면처리에 의해서 표면 전하의 종류 및 전하밀도를 조절할 수 있으며, 이에 따라서 양이온 혹은 음이온 교환막으로 제작될 수 있다. 표면처리법으로는 양극산화된 산화물의 -OH 를 이용한 실란화 공정을 이용한 방법, 대전된 고분자전해질을 이용한 층상자기조립법, 혹은 수열합성법이 있으며, 이를 이용하여 이온 다이오드막의 표면에 표면전하의 종류 및 밀도를 조절할 수 있다. In addition, the method of manufacturing an ion diode film of the present invention may further include (e) surface treating the ion diode film by a method selected from the group consisting of a silanization process, a layer box assembly method, and a hydrothermal synthesis method. The anodized ion diode membrane can control the type and charge density of surface charges by surface treatment, and thus can be fabricated as a cation or anion exchange membrane. Surface treatment methods include a method of silanization using -OH of anodized oxide, layered box assembly method using charged polymer electrolyte, or hydrothermal synthesis method. Can be adjusted.
도 3은 본 발명의 일 구체예에 따른 양극산화를 이용한 이온 다이오드막의 제조방법으로서, (a) 양극산화를 위한 금속(알루미늄 포일) 및 전해질을 준비하는 단계; (a-1) 금속을 양극산화시켜 금속 표면에 산화물을 형성하는 사전 양극산화 단계; (a-2) 금속으로부터 산화물을 선택적으로 제거하는 단계; (a-3) 전해질에 의한 등방성 식각이 일어나지 않는 1차 양극산화를 수행하여 이온 다이오드막의 지지층이 되는 산화물을 형성하는 단계; (b) 전해질에 의한 등방성 식각이 일어나는 2차 양극산화를 수행하여 이온 다이오드막의 다이오드층이 되는 산화물을 형성하는 단계; (c) 금속을 제거하여 산화물의 다공성 템플레이트를 얻는 단계; (d) 다공성 템플레이트의 하부를 제거하여 관통된 이온 다이오드막을 얻는 단계 및 (e) 이온 다이오드막의 표면전하밀도를 조절하기 위한 표면처리 단계를 포함한다. 3 is a method of manufacturing an ion diode membrane using anodization according to an embodiment of the present invention, comprising: (a) preparing a metal (aluminum foil) and an electrolyte for anodizing; (a-1) pre-anodizing step of anodizing the metal to form an oxide on the metal surface; (a-2) selectively removing oxides from the metal; (a-3) forming an oxide serving as a support layer of the ion diode membrane by performing primary anodization in which isotropic etching by the electrolyte does not occur; (b) performing a second anodization in which isotropic etching by the electrolyte is performed to form an oxide serving as a diode layer of the ion diode membrane; (c) removing the metal to obtain a porous template of the oxide; (d) removing the lower portion of the porous template to obtain a penetrated ion diode film, and (e) surface treatment to control the surface charge density of the ion diode film.
경우에 따라 (a-1) 및 (a-2) 공정을 진행하지 않고, (a)의 알루미늄 포일 위에 (a-3)의 양극산화 공정을 진행할 수 있다. 또한, (e)의 표면처리는 (b), (c), 공정 다음에 진행할 수 있다. 또한, 지지층을 형성하지 않고 다이오드층만 형성하는 경우에는 상기 (a-3) 단계를 생략할 수 있다. In some cases, the anodization process of (a-3) may be performed on the aluminum foil of (a) without performing the steps (a-1) and (a-2). In addition, the surface treatment of (e) can be progressed after (b) and (c) and a process. In addition, in the case of forming only the diode layer without forming the support layer, step (a-3) may be omitted.
상기 (b) 단계에서 하기 수학식 1에 따라 양극산화 공정의 인가전압을 조절하여 이온 다이오드막의 격자상수를 결정할 수 있다. In step (b), the lattice constant of the ion diode layer may be determined by adjusting the applied voltage of the anodization process according to Equation 1 below.
[수학식 1][Equation 1]
격자상수 (nm)= 2.5 (nm/V) x U (V) Lattice constant (nm) = 2.5 (nm / V) x U (V)
(상기 식에서, U는 인가전압임.)(Where U is an applied voltage)
상기 수학식 1과 실시예의 표 1을 참조하면 전해질의 종류와 양극산화에 걸리는 전압에 따라 나노 다공 층의 격자 상수를 조절할 수 있으며, 초기 직경은 전해질과 전압에 따라 결정됨을 알 수 있다. 이 때 형성되는 나노구조층은 육방정계의 구조를 가지며, 기공의 직경은 등방성 식각공정을 통하여 양극산화 후에 조절 가능하며, 등방성 식각으로 얻어진 나노다공의 최종 직경은 초기 직경보다 크거나 격자상수보다 작은 범위에서 조절될 수 있다. Referring to Equation 1 and Table 1 of the embodiment, it can be seen that the lattice constant of the nanoporous layer can be adjusted according to the type of electrolyte and the voltage applied to anodization, and the initial diameter is determined according to the electrolyte and the voltage. The nanostructure layer formed at this time has a hexagonal structure, and the pore diameter is adjustable after anodization through an isotropic etching process, and the final diameter of the nanoporous obtained by isotropic etching is larger than the initial diameter or smaller than the lattice constant. Can be adjusted in a range.
양극산화 공정을 수행하면 사전 양극산화 공정을 통해서 생성된 정렬되지 않았던 기공들의 분포가 정렬된 육방정계 구조를 가지게 되며, 직경(pore diameter)이 균일하게 된다. When the anodization process is performed, the distribution of the unaligned pores generated through the pre-anodization process is arranged in a hexagonal structure, and the pore diameter is uniform.
그러나, 본 발명의 이온 다이오드막과 같이 균일한 다공을 요구하지 않을 경우에는 수학식 1에 따라서 다양한 전해질과 전압조건에서 양극산화가 진행될 수 있으며, 예컨대 1M 황산 혹은 옥살산에서는 1nm 이하의 직경을 가지는 2.5nm 격자상수의 나노다공의 제조도 가능하다. 따라서 본 발명의 양극산화 조건은 다공성 양극산화가 가능한 다양한 조건으로 확대될 수 있다.However, when uniform porosity is not required as in the ion diode membrane of the present invention, anodization may proceed under various electrolytes and voltage conditions according to Equation 1, for example, 2.5 M having a diameter of 1 nm or less in 1 M sulfuric acid or oxalic acid. It is also possible to produce nanoporous with nm lattice constant. Therefore, the anodization conditions of the present invention can be extended to various conditions capable of porous anodization.
도 4는 이온 다이오드막의 나노기공을 제어하는 방법을 나타내는 모식도로서, 본 발명의 일 구체예에 따른 나노기공의 형태를 조절하기 위하여 개발된 1차 양극산화(저온 양극산화법)과 2차 양극산화(고온 사각펄스 양극산화 방법)(도 3의 a-3 및 b)의 이해를 돕기 위한 것이다. 본 명세서에서 “저온”과 “고온”은 상대적인 양극산화 공정온도를 의미하며, “저온”은 양극산화 공정 중에서 사용한 전해질에 의한 등방성 식각이 일어나지 않는 조건의 온도를, “고온”은 양극산화 공정 중에 사용한 전해질에 의해 등방성 식각이 일어나는 조건의 온도를 의미하고, 이러한 온도는 전해질에 따라, 혹은 생산속도 및 형태에 따라 결정될 수 있다. 예컨대, 셀렌산 수용액 전해질 및 알루미늄 금속을 사용하는 경우, 저온 양극산화는 -10℃ 내지 10℃에서 수행될 수 있고, 고온 양극산화는 20℃ 내지 80 ℃에서 수행될 수 있다.4 is a schematic diagram illustrating a method for controlling nanopores of an ion diode membrane, wherein primary anodization (low temperature anodization) and secondary anodization (developed to control the shape of nanopores according to one embodiment of the present invention) are used. High temperature square pulse anodization method) (a-3 and b of FIG. 3) to help understand. In the present specification, "low temperature" and "high temperature" refer to a relative anodization process temperature, and "low temperature" refers to a temperature at which isotropic etching does not occur by an electrolyte used during anodization, and "high temperature" refers to an anodization process. It refers to the temperature of the conditions under which isotropic etching occurs by the electrolyte used, this temperature can be determined depending on the electrolyte, or the production rate and shape. For example, when using an aqueous solution of selenic acid and an aluminum metal, low temperature anodization may be performed at -10 ° C to 10 ° C, and high temperature anodization may be performed at 20 ° C to 80 ° C.
우선 이온 다이오드막의 나노기공의 격자상수(밀집도) 및 초기 기공직경에 따라서 전해질과 인가전압을 결정한다. 도 5는 본 발명의 일 구체예에 의한 설계 된 나노기공의 예를 보여준다. 나노기공의 형태를 지지층의 길이와 직경, 그리고 다이오드층의 길이와 직경, 경사의 프로파일(경사진 기공의 다이오드층을 여러개의 구간으로 나누어 각각의 구간의 길이와 직경)을 설계한다. First, the electrolyte and the applied voltage are determined according to the lattice constant (density) and initial pore diameter of the nanopores of the ion diode membrane. Figure 5 shows an example of the nanopores designed according to one embodiment of the present invention. The shape of the nanopores is designed for the length and diameter of the support layer, the length and diameter of the diode layer, and the profile of the slope (dividing the inclined pore diode layer into several sections).
(a-3) 단계에서는 전해질에 의한 등방성 식각이 일어나지 않는 1차 양극산화(저온 양극산화)를 수행하여 이온 다이오드막의 지지층이 되는 산화물을 형성한다. 하기 수학식 2와 같이, 지지층의 길이(LL)는 양극산화 시간(tL)에 비례하므로, 양극산화 시간에 따라 지지층의 길이(LL)가 조절될 수 있다. 또한 등방성 식각이 일어나지 않으므로, 지지층 나노다공의 직경(DL)은 초기 직경과 거의 같다. (통상적으로 같다고 표현하지만, 등방성 식각이 전혀 일어나지 않는 것이 아니라 억제되는 것이므로 엄밀히 따지면 저온 양극산화를 하더라도 처음 생긴 기공과 마지막에 생긴 기공의 직경은 약간의 차이가 있다. 공정 시간은 생산성 즉 비용문제이기 때문에 최종 산업화 단계에서는 효율에 큰 변화가 없다면 저온 양극산화 공정 온도를 높일 수 있으나, 고온 양극산화 보다는 낮은 온도에서 실시된다.)In the step (a-3), primary anodization (low temperature anodization) in which isotropic etching by an electrolyte is performed is performed to form an oxide serving as a support layer of the ion diode layer. As shown in Equation 2, since the length L L of the support layer is proportional to the anodization time t L , the length L L of the support layer may be adjusted according to the anodization time. In addition, since isotropic etching does not occur, the diameter D L of the support layer nanoporous is almost equal to the initial diameter. (It is usually expressed as the same, but isotropic etching does not occur at all, but it is suppressed, so strictly speaking, even when cold anodizing, there is a slight difference between the diameter of the first pore and the last pore. Therefore, in the final industrialization stage, if the efficiency does not change significantly, the low temperature anodization process temperature can be increased, but it is performed at lower temperature than the high temperature anodization.
[수학식 2][Equation 2]
지지층의 길이 (LL) = 1차 양극산화에서 산화막 성장속도 (vs) x 1차 양극산화 시간 (ts) Support layer length (L L ) = oxide growth rate in primary anodization (v s ) x primary anodization time (t s )
상기 산화막 성장속도는 기공을 포함하는 산화막의 성장속도이며, 동일한 전압과 전해질 조건이라면, 동일한 온도에서 산화막의 성장속도는 일정하고, 온도가 증가할수록 성장속도는 증가한다. The oxide film growth rate is a growth rate of an oxide film including pores, and under the same voltage and electrolyte conditions, the growth rate of the oxide film is constant at the same temperature, and the growth rate increases with increasing temperature.
(b) 단계에서는 전해질에 의한 등방성 식각이 일어나는 2차 양극산화(고온 (사각펄스) 양극산화)를 수행하여 이온 다이오드막의 다이오드층이 되는 산화물을 형성한다. 여기서 사각펄스는 1차 양극산화와 동일한 인가전압과 0V의 사각펄스이다. 여기서 0V는 양극산화가 일어나지 않는 전압을 의미하며, 인가전압 이하의 전압조건이 될 수 있다. 사각파의 사이클의 개수와 다이오드층의 나눈 구간의 개수는 같다. 도 4의 h)는 사각파의 형태를 나타내는 모식도이다. 즉 n번 사이클의 고온 사각펄스 양극산화공정은 n개 구간을 가지는 다이오드층을 형성한다. c) 및 d)의 1번 사이클에서 1구간의 기공을 지지층의 아래 형성한다. 1번 사이클로부터 형성된 1구간의 길이(LH1)와 직경(DH1)은 전압인가 시간(tH1)과 1구간의 주기 시간(TH1)으로부터 하기 수학식 3 및 수학식 4을 통해 결정된다. 여기서 2차 양극산화는 등방성 식각이 일어나는 조건이므로 전해액에 노출되어 있는 지지층의 원통형 기공은 등방성 식각을 받는다. 그러므로 TH1이 진행되는 동안 지지층의 직경(DL)은 수학식 4에 따라 증가한다. e) 및 f)의 2번 사이클로부터 1구간 아래 2구간이 형성되며, 형성된 2구간의 길이(LH2)와 직경(DH2)은 전압인가 시간(tH2)과 2구간의 주기 시간(TH2)으로부터 결정된다. 여기서 지지층과 1구간의 기공 직경은 TH2에 의존하여 증가한다. 위와 같이 n번 사이클의 고온 사각펄스 양극산화 공정을 진행하면 i 번째 구간의 길이(LHi)는 i 번째 전압인가 시간(tHi)에 의해 결정된다. 또한 기공 바닥부터 i 번째 구간의 높이 (zi)은 tHi부터 tHn까지 누적된 전압인가시간()으로 결정된다. 전체 다이오드층의 길이는 전체 누적된 전압인가시간()으로 결정된다. 또한, i 번째 구간의 다공직경(DHi)은 THi에서 THn까지 누적된 주기시간()으로부터 결정된다. 그리고 DL와 DH1은 전체 누적된 주기시간()으로부터 결정된다. 위의 원리를 이용하면 설계에 따라서 1차 양극산화 시간, 2차 양극산화의 각 사이클에서 주기시간과 전압인가 시간을 조절하면, 이온 다이오드막 내부의 나노다공 형태를 자유롭게 조절할 수 있으며, 다양한 특성의 이온 다이오드막 제조가 가능하다. 또한 공정은 프로그램으로부터 간단히 제어가 가능하므로 n의 개수는 매우 많을 수 있으며, 그로부터 정교한 형태 제어가 가능하다. In step (b), secondary anodization (high temperature (square pulse) anodization) in which isotropic etching by the electrolyte is performed to form an oxide that becomes a diode layer of the ion diode film. Here, the square pulse is a square pulse of 0V and the same applied voltage as the first anodization. Here, 0V means a voltage at which anodization does not occur, and may be a voltage condition below an applied voltage. The number of cycles of the square wave is equal to the number of divisions of the diode layer. 4) is a schematic diagram which shows the shape of a square wave. That is, the n-cycle high-temperature square pulse anodization process forms a diode layer having n sections. In cycles 1) of c) and d), a section of pores is formed under the support layer. The length L H1 and the diameter D H1 of one section formed from the first cycle are determined by the following Equations 3 and 4 from the voltage application time t H1 and the cycle time T H1 of one section. . Since secondary anodization is a condition in which isotropic etching occurs, the cylindrical pores of the support layer exposed to the electrolyte are subjected to isotropic etching. Therefore, the diameter D L of the support layer increases while the T H1 proceeds according to the equation (4). e) and f) two sections below one section are formed, and the length (L H2 ) and the diameter (D H2 ) of the two sections are the voltage application time (t H2 ) and the cycle time (T) of the two sections. H2 ). Here the pore diameter of the support layer and one section increases depending on T H2 . When the high-temperature square pulse anodization process of n cycles is performed as described above, the length L Hi of the i th section is determined by the i th voltage application time t Hi . Also, the height (z i ) of the i-th section from the bottom of the pore is the accumulated voltage application time from t Hi to t Hn ( Is determined by). The length of all diode layers is the total accumulated voltage application time ( Is determined by). In addition, the pore diameter (D Hi ) of the i-th section is the period time accumulated from T Hi to T Hn ( Is determined from And D L and D H1 are the total accumulated cycle time ( Is determined from Using the above principle, by adjusting the cycle time and the voltage application time in each cycle of the first anodization time and the second anodization time according to the design, it is possible to freely control the nanopore shape inside the ion diode membrane. Ion diode film production is possible. In addition, since the process can be easily controlled from the program, the number of n can be very large, and precise shape control is possible therefrom.
[수학식 3][Equation 3]
다이오드층의 길이 (LH) = 2차 양극산화에서 산화막 성장속도 (vH) x 전압인가 시간 (tH) Length of diode layer (L H ) = oxide growth rate in secondary anodization (v H ) x voltage application time (t H )
[수학식 4][Equation 4]
다이오드층의 직경 (DH) = 2차 양극산화에서 식각속도 (eH) x 주기 시간 (TH)+초기직경 Diameter of diode layer (D H ) = etch rate (e H ) x cycle time (T H ) + initial diameter in secondary anodization
도 6은 본 발명의 실시예에서 고온 사각펄스 양극산화법으로 제작된 다이오드층의 전자현미경 이미지로서, 고온 사각펄스에 의한 형태 제어를 확인할 수 있다. FIG. 6 is an electron microscope image of a diode layer manufactured by a high temperature square pulse anodization in an embodiment of the present invention, and the shape control by the high temperature square pulse can be confirmed.
상기 (b) 단계가 수행된 후, (c) 금속을 제거하여 산화물의 다공성 템플레이트를 얻는 단계; 및 (d) 다공성 템플레이트의 하부를 제거하여 관통된 이온 다이오드막을 얻는 단계가 수행될 수 있다. 특별히 한정하지 않으나, 습식 식각 또는 건식 식각을 통해 다공성 템플레이트의 하부를 제거할 수 있다. After the step (b) is performed, (c) removing the metal to obtain a porous template of the oxide; And (d) removing the lower portion of the porous template to obtain a penetrated ion diode film. Although not particularly limited, the lower portion of the porous template may be removed by wet etching or dry etching.
본 발명의 이온 다이오드막은 특별히 한정하지 않으나, 표면이 양전하 또는 음전하로 대전된 것으로서, 정류비가 2~1000일 수 있다. 본 발명의 이온 다이오드막의 용도는 특별히 한정하지 않으며, 예를 들어 전기적 탈염기술, 산/알칼리의 생산, 산업폐수의 중금속의 제거, 해수의 담수화, 반도체 산업의 초순수의 제조, 해수에서 식염의 제조, 발효산업의 유기산 및 아미노산의 회수, 염분차 발전 등에 사용될 수 있다. The ion diode film of the present invention is not particularly limited, but the surface of the ion diode film is positively or negatively charged, and the rectification ratio may be 2 to 1000. The use of the ion diode membrane of the present invention is not particularly limited and includes, for example, electrical desalination technology, production of acid / alkali, removal of heavy metals from industrial wastewater, desalination of seawater, production of ultrapure water in the semiconductor industry, production of salt in seawater, It can be used for the recovery of organic acids and amino acids in the fermentation industry, the development of salt difference.
이하, 실시예를 통하여 본 발명을 보다 상세하게 설명한다. 그러나, 본 발명의 범위가 이들로 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited to these.
[[
실시예Example
]]
1. 이온 1.ion
다이오드막의Diode film
격자 상수와 기공의 초기 Lattice Constants and Initial Porosity
직경diameter
하기 표 1은 기재된 조건으로 전해질 및 인가전압을 달리하였을 때 기공의 초기 직경 및 격자 상수를 전자현미경을 이용하여 측정하였다. Table 1 shows the initial diameter and the lattice constant of the pores when the electrolyte and the applied voltage were changed under the conditions described using an electron microscope.
[표 1]TABLE 1
표 1의 결과가 상기 수학식 1에 부합되고, 전해질의 종류와 양극산화에 인가 전압에 따라 나노 다공 층의 격자 상수를 조절할 수 있으며, 초기 직경은 전해질과 전압에 따라 결정됨을 알 수 있었다.The results of Table 1 are in accordance with Equation 1, it can be seen that the lattice constant of the nanoporous layer can be adjusted according to the type of electrolyte and the voltage applied to the anodization, the initial diameter is determined by the electrolyte and the voltage.
2. 이온 2. ions
다이오드막의Diode film
제조 Produce
아세톤에 알루미늄 포일(순도: >99.95)을 담그어 초음파로 유기물을 세척한 후, 왕수 (HCl(hydrochloric acid) 20m, HNO3(nitric acid) 10ml, 증류수 70ml 및 HF(hydrofluoric acid) 1ml의 혼합물에 담가 표면 불순물을 제거하고, 증류수로 세척하였다. 불순물이 제거된 알루미늄 포일을 N2 분위기에서 500℃로 12시간 열처리하였다. 그 후, 알루미늄 표면의 미세한 요철을 제거하기 위하여 전해연마를 실시하였다. 전해연마로 처리된 표면이 매끄러운 알루미늄 포일을 48V, 0.3M의 셀렌산 수용액을 전해질로 사용하여 사전 양극산화를 0℃에서 12시간 실시하였다. 이후 양극산화로부터 형성된 산화물을 크롬산 수용액 (1.8g CrO3 + 7.1g H3PO4 (85%) 및 증류수 (100mL까지 채움) 의 혼합물을 이용하여 제거하였다. 산화물이 제거된 알루미늄 표면에는 약 115nm 격자상수의 육방정계의 패턴이 남아있는 것을 전자현미경으로 확인하였다. Aluminum in acetone foil (purity:> 99.95) After washing the organic material to a submerged ultrasonic, aqua regia (HCl (hydrochloric acid) 20m, HNO 3 (nitric acid), 10ml, distilled water 70ml and HF (hydrofluoric acid) soaked in a mixture of 1ml The surface impurities were removed and washed with distilled water The aluminum foil from which impurities were removed was heat-treated for 12 hours at 500 ° C. in N 2 atmosphere, and then electropolishing was performed to remove fine irregularities on the aluminum surface. Aluminium foil with a smooth surface was treated with 48 V, 0.3 M aqueous solution of selenic acid as an electrolyte, and pre-anodized for 12 hours at 0 ° C. The oxide formed from anodization was then subjected to an aqueous solution of chromic acid (1.8 g CrO 3 + 7.1 g H 3 PO 4 (85% ) and was removed by using a mixture of distilled water (up to fill 100mL). aluminum oxide has been removed, the surface of the hexagonal pattern of about 115nm lattice parameter remains It was confirmed by electron microscopy.
도 1-b와 같이 원뿔형의 다이오드층을 가지는 이온다이오드막을 설계하였으며, 지지층의 길이(LL)와 직경(DL)은 30μm와 90nm, 다이오드층의 길이(LL)와 최소직경(n구간의 직경, DHn)은 1.25μm, 9nm로 설계하였다. 0.3M 셀렌산수용액, 48V로 양극산화를 진행하면, 초기직경은 9nm이며, 0℃ 조건에서 성장속도(vs)는 50nm/min, 35℃ 조건에서 성장속도(vH)는 417nm/min, 식각속도(eH)는 0.135nm/min이다. n개 구간의 원뿔형 다이오드층은 각 구간에서 전압인가시간은 tH1=tH2=....=tHn=LH/(n·vH)이며, 주기시간은 TH1=TH2=....=THn=(DL-초기직경)/(n·eH)이다.As shown in Fig. 1-b, an ion diode layer having a conical diode layer was designed, and the length (L L ) and diameter (D L ) of the support layer were 30 μm and 90 nm, and the length (L L ) and minimum diameter (n section) of the diode layer. Diameter, D Hn ) was designed to 1.25μm, 9nm. When anodized with 0.3M aqueous solution of selenic acid at 48V, the initial diameter was 9 nm, the growth rate (v s ) was 50 nm / min at 0 ° C., and the growth rate (v H ) was 417 nm / min at 35 ° C. The etching rate e H is 0.135 nm / min. In the conical diode layers of n sections, the voltage application time in each section is t H1 = t H2 = .... = t Hn = L H / (n · v H ), and the cycle time is T H1 = T H2 =. ... = T Hn = (D L -initial diameter) / (n · e H ).
육방정계 패턴이 있는 알루미늄 포일에 대해 사전 양극산화 조건과 동일한 48V, 0.3M의 셀렌산 수용액을 전해질로 사용하여 0℃조건에서 1차 양극산화를 진행하여 지지층을 제작하였다. 이 때 양극산화시간은 설계된 지지층의 길이에 따라서 수학식 2에 의하여 결정하여 10시간 동안 진행하였고 30um의 지지층을 형성하였다. 즉각적으로 온도를 35℃로 올린 후, 2차 사각펄스 양극산화 공정을 전압인가시간은 1초, 주기시간은 200초, n은 180으로 총 10시간 동안 진행하였고 1.25nm의 다이오드층을 형성하였다. 사각펄스 양극산화 공정 중 등방성 식각으로 지지층의 직경은 90nm가 형성되었다.A support layer was fabricated by first anodizing at 0 ° C. using 48V and 0.3M aqueous solution of selenic acid, which was the same as the pre-anodization condition, for an aluminum foil having a hexagonal pattern. At this time, the anodization time was determined by Equation 2 according to the designed support layer length and proceeded for 10 hours to form a support layer of 30um. Immediately after the temperature was raised to 35 ° C, the second square pulse anodization process was carried out for 10 hours with a voltage application time of 1 second, a cycle time of 200 seconds, and n of 180 to form a diode layer of 1.25 nm. An isotropic etching of the square pulse anodization process resulted in 90 nm diameter of the support layer.
2차 사각펄스 양극산화를 마친 후 증류수에 세척하고, 양극산화 되지 않은 알루미늄은 1M의 SnCl4 용액에 담가 제거하여 경사진 다공이 있는 산화막을 얻었다. 한쪽 기공이 막혀 있는 다공들의 바닥을 크롬산 수용액으로 습식 식각하여, 관통된 이온 다이오드막을 제조하였다. 제조된 이온 다이오드막을 3-머캅토프로필 트리메톡시실란(3-mercaptopropyl trimethoxysilane, MPTS, HS(CH2)3Si(OCH3)3)와 아세톤의 1:100 용액에 12시간 담가서 실란화 공정으로 표면처리하여, 표면에 -SH 작용기를 도입하였고, 아세톤으로 세척하였다. 그 후, 이온 다이오드막을 30% H2O2 수용액에 하루 담가 처리한 후 건조시켰다. 양극산화된 산화물의 표면은 일반적으로 -OH 작용기를 가지지만, 상기 실란화 공정과 과산화수소처리로 -SO3H 작용기를 갖는 이온 다이오드막을 제조하였다. 상기와 같이 제조된 이온 다이오드막을 전자현미경으로 촬영하여 도 7의 a 및 b에 나타내었으며 설계에 따라 1.25μm 원뿔형 다이오드층과 30μm 지지층을 가지는 이온 다이오드막이 제조되었다.After the completion of the second square pulse anodization, it was washed with distilled water, and the aluminum which was not anodized was immersed in 1M SnCl 4 solution to obtain an oxide film with slanted pores. The bottom of the pores with one pore blocked was wet etched with an aqueous solution of chromic acid to prepare a penetrated ion diode membrane. The prepared ion diode membrane was immersed in a 1: 100 solution of 3-mercaptopropyl trimethoxysilane (MPTS, HS (CH 2 ) 3 Si (OCH 3 ) 3 ) and acetone for 12 hours in a silanization process. By surface treatment, -SH functional groups were introduced to the surface and washed with acetone. Thereafter, the ion diode membrane was soaked in 30% H 2 O 2 aqueous solution for one day, and then dried. The surface of the anodized oxide generally has a -OH functional group, but an ion diode membrane having a -SO 3 H functional group was prepared by the silanization process and hydrogen peroxide treatment. The ion diode film prepared as described above was photographed with an electron microscope, and is shown in FIGS. 7A and 7B. According to the design, an ion diode film having a 1.25 μm conical diode layer and a 30 μm support layer was manufactured.
도 8은 본 발명의 실시예에서 제조된 이온 다이오드막을 100mM의 NaCl 수용액 사이에 위치시켜 측정한 전류-전압곡선으로서, 이온의 정류특성을 보여준다. 100mM의 NaCl 수용액에서 측정되었으며 도 8의 a)는 표면처리를 하지 않은 경우 이온 다이오드막의 정류특성을, 도 8의 b)는 실란화 공정으로 -SO3H 작용기로 표면처리된 경우 이온 다이오드막의 정류특성을 나타낸다. 도 8로부터 본 발명의 공정으로 0.1M의 고농도, +1V와 -1V의 전류량으로 계산된 정류 비(rectification ratio)가 약 23과 2.5인 양이온과 음이온 다이오드막의 제작이 가능함을 확인할 수 있다.FIG. 8 is a current-voltage curve measured by placing an ion diode membrane prepared in an embodiment of the present invention between 100 mM NaCl aqueous solution, and shows rectification characteristics of ions. Measured in 100mM NaCl aqueous solution, Figure 8a) shows the rectification characteristics of the ion diode membrane without surface treatment, and Figure 8b) shows rectification of the ion diode membrane when surface treated with -SO 3 H functional group by silanization process. Characteristics. From the process of Figure 8 it can be seen that the cation and anion diode film having a rectification ratio of about 23 and 2.5 calculated by the high concentration of 0.1M, the current amount of + 1V and -1V can be confirmed.
도 9는 해수(500mM NaCl)와 담수(10mM NaCl) 사이에 양이온 다이오드막을 위치시켜 측정한 전류-전압곡선을 보여준다. 전류-전압곡선의 개방전압(Voc)과 단락전류(Isc)로 전략량, P=(VocxIsc)/4을 계산하여 단위면적 당 약 1.2W/m2의 전기에너지 생산이 가능함을 확인하였다. 이는 하기 표 2의 기존 상용화된 양이온교환막에 비해 3~5배 정도 높은 값이다. 9 shows a current-voltage curve measured by placing a cationic diode film between seawater (500 mM NaCl) and fresh water (10 mM NaCl). It is possible to produce about 1.2W / m 2 of electric energy per unit area by calculating the strategic amount, P = (V oc xI sc ) / 4, based on the open-circuit voltage (V oc ) and the short-circuit current (I sc ) of the current-voltage curve. It was confirmed. This is 3 to 5 times higher than the conventional commercialized cation exchange membrane of Table 2 below.
[표 2]TABLE 2
Claims (13)
- 입구와 출구의 직경이 서로 상이한, 경사가 있는 나노기공이 집적된 이온 다이오드막으로서,A slanted nano-pore integrated ion diode membrane having different diameters of inlet and outlet,상기 나노기공은 깊이 변화에 따라 기공 내 통로 직경이 변화하는 다이오드층을 포함하는 것을 특징으로 하는 이온 다이오드막.The nano-pores are ion-diode membrane, characterized in that it comprises a diode layer in which the passage diameter changes in the pore according to the depth change.
- 제1항에 있어서, 상기 나노기공은, 깊이 변화에 따라 기공 내 통로 직경의 변화가 없는 지지층; 및 깊이 변화에 따라 기공 내 통로 직경이 변화하는 다이오드층을 포함하는 것을 특징으로 하는 이온 다이오드막.According to claim 1, wherein the nano-pores, the support layer does not change the passage diameter in the pore according to the depth change; And a diode layer in which the passage diameter in the pores changes according to the depth change.
- 제1항에 있어서, 격자상수는 2~1,000 nm인, 이온 다이오드막.The ion diode film of Claim 1 whose lattice constant is 2-1,000 nm.
- 제1항에 있어서, 이온 다이오드막의 재질은 알루미늄, 티타늄, 지르코늄, 하프늄, 탄탈룸, 니오븀 및 텅스텐으로 구성되는 그룹으로부터 선택되는 금속의 산화물인, 이온 다이오드막.The ion diode film according to claim 1, wherein the material of the ion diode film is an oxide of a metal selected from the group consisting of aluminum, titanium, zirconium, hafnium, tantalum, niobium, and tungsten.
- 제1항에 있어서, 정류 비가 2~1000 인, 표면이 양전하 또는 음전하로 대전된, 이온 다이오드막.The ion diode film according to claim 1, wherein the surface of the rectification ratio is 2 to 1000, and the surface is charged with a positive charge or a negative charge.
- (a) 양극산화를 위한 금속 및 전해질을 준비하는 단계;(a) preparing a metal and an electrolyte for anodization;(b) 전해질에 의한 등방성 식각이 일어나는 2차 양극산화를 수행하여 이온 다이오드막의 다이오드층이 되는 산화물을 형성하는 단계;(b) performing a second anodization in which isotropic etching by the electrolyte is performed to form an oxide serving as a diode layer of the ion diode membrane;(c) 금속을 제거하여 산화물의 다공성 템플레이트를 얻는 단계; 및(c) removing the metal to obtain a porous template of the oxide; And(d) 다공성 템플레이트의 하부를 제거하여 관통된 이온 다이오드막을 얻는 단계를 포함하는 이온 다이오드막의 제조방법.(d) removing the lower portion of the porous template to obtain a penetrated ion diode membrane.
- 제6항에 있어서, 상기 (a) 단계 후에 다음의 단계를 추가로 포함하는 이온 다이오드막의 제조방법:The method of claim 6, further comprising the following step after step (a):(a-1) 금속을 양극산화시켜 금속 표면에 산화물을 형성하는 사전 양극산화 단계; 및(a-1) pre-anodizing step of anodizing the metal to form an oxide on the metal surface; And(a-2) 금속으로부터 산화물을 선택적으로 제거하는 단계.(a-2) selectively removing oxides from the metal.
- 제6항에 있어서, 상기 (b) 단계 전에 다음의 단계를 추가로 포함하는 이온 다이오드막의 제조방법:The method of claim 6, further comprising the following steps before the step (b):(a-3) 전해질에 의한 등방성 식각이 일어나지 않는 1차 양극산화를 수행하여 이온 다이오드막의 지지층이 되는 산화물을 형성하는 단계.(a-3) forming an oxide serving as a support layer of the ion diode membrane by performing primary anodization in which isotropic etching by the electrolyte does not occur.
- 제8항에 있어서, (a-3) 단계에서 하기 수학식 2에 따라 지지층의 길이(LL)를 결정하는, 이온 다이오드막의 제조방법.The method of claim 8, wherein in step (a-3), the length L L of the support layer is determined according to Equation 2 below.
- 제6항에 있어서, (b) 단계에서 하기 수학식 1에 따라 이온 다이오드막의 격자상수를 결정하는, 이온 다이오드막의 제조방법.The method of claim 6, wherein the lattice constant of the ion diode film is determined in the step (b) according to Equation 1 below.[수학식 1][Equation 1]격자상수 (nm)= 2.5 (nm/V) x U (V) Lattice constant (nm) = 2.5 (nm / V) x U (V)(상기 식에서, U는 인가전압임.)(Where U is an applied voltage)
- 제6항에 있어서, (b) 단계에서 하기 수학식 3에 따라 다이오드층의 길이(LH)를 결정하는, 이온 다이오드막의 제조방법.The method of claim 6, wherein in step (b), the length L H of the diode layer is determined according to Equation 3 below.[수학식 3][Equation 3]다이오드층의 길이 (LH) = 2차 양극산화에서 산화막 성장속도 (vH) x 전압인가 시간 (tH) Length of diode layer (L H ) = oxide growth rate in secondary anodization (v H ) x voltage application time (t H )
- 제6항에 있어서, (b) 단계에서 하기 수학식 4에 따라 다이오드층의 직경(DH)를 결정하는, 이온 다이오드막의 제조방법.The method of claim 6, wherein in step (b), the diameter D H of the diode layer is determined according to Equation 4 below.[수학식 4][Equation 4]다이오드층의 직경 (DH) = 2차 양극산화에서 식각속도 (eH) x 주기 시간 (TH) +초기직경Diameter of diode layer (D H ) = etch rate (e H ) x cycle time (T H ) + initial diameter in secondary anodization
- 제6항에 있어서, (e) 실란화 공정, 층상자기조립법 및 수열합성법으로 이루어진 군으로부터 선택되는 방법으로 이온 다이오드막을 표면 처리하는 단계;를 추가로 포함하는, 이온 다이오드막의 제조방법.The method of claim 6, further comprising (e) surface treating the ion diode film by a method selected from the group consisting of a silanization process, a layer box assembly method, and a hydrothermal synthesis method.
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