KR102139952B1 - Membrane Comprising Porous Substrate Layer and CNT/Chitosan Nano Hybrid Coating Layer and Electrostatic Dust Collector System Comprising the Same - Google Patents

Abstract

The present invention relates to a membrane comprising a porous substrate layer and a CNT/chitosan nano hybrid coating layer and an electrostatic dust collection system including the same, and the membrane of the present invention has excellent electrical conductivity, so that dust can be efficiently collected even at a low current. , It has pores and free passage of air, but the long passage of air can collect a large amount of dust. In addition, the membrane of the present invention can be manufactured in various forms and is suitable for application to various types of electrostatic dust collection systems.

Description

Membrane Comprising Porous Substrate Layer and CNT/Chitosan Nano Hybrid Coating Layer and Electrostatic Dust Collector System Comprising the Same}

The present invention relates to a membrane comprising a porous substrate layer and a CNT/chitosan nano hybrid coating layer and an electrostatic dust collection system comprising the same.

Dust is classified into total dust, fine dust, and ultrafine dust according to the particle size. Among them, the fine dust means that the diameter is 10 μm or less, and the ultrafine dust means that the diameter is 2.5 μm or less. Of these, fine dust and ultrafine dust can penetrate human alveoli and become a direct cause of various respiratory diseases after infiltration. The fine dust and ultrafine dust are composed of ionic components such as sulfate, nitrate, and ammonia, and harmful substances such as metal compounds and carbon compounds. These substances cause photochemical reactions in the atmosphere to produce fine dust and ultrafine dust, and these materials are mainly generated from exhaust gas from automobiles or smoke from factories. Due to the harmfulness of these substances, the concentration of fine dust and ultra fine dust is strictly regulated in countries around the world.

Fine dust is generally about 1/10 of the thickness of the hair, while ultrafine dust is a very small size of about 1/40 or less. do. This causes heart disease and respiratory disease.

In Korea, yellow dust originates from China in the spring, and recently, inland desertification has occurred in China due to global warming, and the occurrence of yellow dust is also accelerating. It is analyzed that yellow dust from China is five times higher than domestic yellow sand, and in Beijing, heavy metal concentrations are three times that of Korea, so it is highly likely to damage the bronchus when exposed for a long time. Therefore, it is necessary to wear a mask that can remove fine dust when going out.

In addition, not only yellow dust, but also the occurrence of fine dust due to air pollution is a major problem that threatens health, and a meticulous environment that should not have impurities, such as an operating room, an intensive care unit, and a semiconductor processing room. , It is very important to block fine dust and ultra fine dust even in places such as office spaces where printers are frequently used. Therefore, the development of filters for vehicles, masks, printers, air purifiers, air conditioners, electric vacuum cleaners, special clean rooms, and the like, which can remove such fine or ultrafine dust, is becoming important.

Existing anti-vibration filters use a filter method using a woven fabric or a non-woven fabric. That is, a filter having pores smaller than the size of the particles was manufactured, and a method of filtering particles having a larger size was selected. However, this conventional anti-vibration filter has two problems. First, there is a limit to removing nano-sized fine particles having a particle size smaller than 2.5 μm. Second, in order to effectively remove fine dust and ultra fine dust, the pores of the filter have to be small, which causes a problem that air movement becomes difficult. As a result, it is necessary to manufacture an anti-vibration filter that has pores of a suitable size and freely enters and exits air, and can effectively remove ultra-fine dust.

Republic of Korea Registered Patent Publication No. 10-0978602 Republic of Korea Registered Patent Publication No. 10-1296615

An object of the present invention is to provide an electrostatic dust collection system including a membrane and a membrane capable of effectively collecting fine dust with a low current, having excellent pore size, free air entry, and excellent electrical conductivity.

In order to solve the above problems, the inventors of the present invention have completed the present invention by preparing a membrane that has pores of a suitable size, has excellent electrical conductivity, and can effectively collect fine dust even at a low current. Accordingly, the means for solving the problems of the present invention are as follows:

1. A porous substrate layer and a CNT/chitosan nanohybrid coating layer coated on the porous substrate layer, wherein the CNT/chitosan nanohybrid has a CNT core surrounded by a chitosan shell, and the porous substrate is an organic porous substrate, an inorganic porous substrate, or Combination of these, the organic porous substrate is selected from the group consisting of cotton, wool, cellulose, methyl cellulose, carboxymethyl cellulose, polystyrene, polyethylene, polyurethane, polyacetate and nylon, the inorganic porous substrate is carbon fiber, A membrane selected from the group consisting of ceramics and silicates.

2. An electrostatic dust collection system comprising the membrane of 1 above.

The membrane of the present invention has excellent electrical conductivity, including CNTs in a high content, and has excellent structural stability, so that it can efficiently collect fine dust or ultrafine dust even at a low current. In addition, by coating CNT/chitosan nano-hybrid on the porous substrate, the pores of sufficient size have free air, and the passage of air is long to collect a large amount of fine dust. Accordingly, the membrane of the present invention is suitable for use in an electrostatic dust collection system.

1 schematically illustrates the core-shell structure of a CNT/chitosan membrane.
Figure 2 is a simplified diagram of the case where the membrane layer is disposed on both sides of the filtration layer in the electrostatic dust collection system of the present invention.
3 is a simplified diagram of a case in which the membrane layer is disposed on one side of the filtration layer in the electrostatic dust collection system of the present invention.
Figure 4 is an HR-TEM (A), FE-SEM (B) images and pictures (C) of CNT-chitosan 50.
5 is an enlarged SEM image of FIG. 4C.
6 is an HR-TEM image of CNT-chitosan 25, 50, 75 and pure CNT (pCNT).
7 shows the FTIR spectrum of pure CNT, chitosan and CNT/chitosan membranes.
8 shows a graph showing the results of thermogravimetric analysis of pure CNT, chitosan and CNT/chitosan membranes.
9A is a graph showing changes in thickness and sheet resistance according to CNT weight percent change of CNT/chitosan membrane, and FIG. 9B is a graph showing changes in tensile strength and modulus of elasticity according to CNT weight percent change.
10 is a graph showing a change in elongation according to CNT weight percent change of the CNT/chitosan membrane.
11 is a graph showing the tensile-stress curves of pure chitosan and CNT-chitosan 25, 50, 75, 85.
FIG. 12 is a diagram showing Raman spectra of pure chitosan and CNT/chitosan membranes.
13 is a diagram showing XPS data C 1s(A), N 1s(B), and O 1s(C) of the CNT/chitosan membrane.
14 to 18 are views showing the results of observing the membrane surface of the present invention by SEM image when exposed to external air for 3 hours under a voltage of 0 to 12 V. 16, 9V, and 17, 12V, respectively.
19 is a comparison of the membrane surface of the present invention after adsorbing fine dust and after washing it.
Figure 20 shows a photograph and SEM image of the CNT Coated U-Sponge membrane prepared in Example 2 of the present invention.
Figure 21 shows a photo and SEM image of the CNT Coated U-Fiber membrane prepared in Example 2 of the present invention.
Figure 22 shows a photo and SEM image of the CNT Coated C-Fiber membrane prepared in Example 2 of the present invention.
Figure 23 shows a photograph of a cylindrical electrostatic dust collection system produced using the CNT Coated U-Sponge membrane produced in Preparation Example 2-4 of the present invention.
24 is a graph showing the results of measuring the fine dust removal rate of the cylindrical electrostatic dust collection system produced in Production Example 2-4 of the present invention.
25 is a conceptual diagram of a planar electrostatic dust collection system manufactured in Production Example 2-5 of the present invention and shows a photograph of an actual production example.
26 shows a conceptual diagram of a planar electrostatic dust collection system manufactured in Production Example 2-6 of the present invention and a photograph of an actual production example.
27 is a conceptual diagram of a planar electrostatic dust collection system manufactured in Production Example 2-7 of the present invention and shows a photograph of an actual production example.
28 is a graph showing the results of measuring the removal rate of fine dust in the case of using 25K CNT Coated U-Sponge among the planar electrostatic dust collection systems prepared in Production Example 2-5 of the present invention.
29 is a graph showing the results of measuring the removal rate of fine dust in the case of using 50K CNT Coated U-Sponge of the planar electrostatic dust collection system prepared in Production Example 2-5 of the present invention.
30 is a graph showing the results of measuring the removal rate of fine dust in the case of using 65K CNT Coated U-Sponge of the planar electrostatic dust collection system prepared in Production Example 2-5 of the present invention.
31 is a graph showing the results of measuring the removal rate of fine dust in the case of using the 50K CNT Coated U-Sponge and Al electrode layers of the planar electrostatic dust collection system prepared in Production Example 2-5 of the present invention.
32 is a graph showing the results of measuring the fine dust removal rate of the planar electrostatic dust collection system prepared in Production Example 2-6 of the present invention.
33 is a graph showing the results of measuring the fine dust removal rate of the planar electrostatic dust collection system prepared in Production Example 2-7 of the present invention.
34 is a photograph of the membrane produced in Preparation Example 2-8 of the present invention.
35 is a photograph of the membrane produced in Preparation Example 2-9 of the present invention.
36 is a photograph of the membrane produced in Preparation Example 2-10 of the present invention.
37 is a photograph of the membrane prepared in Production Example 2-11 of the present invention.
38 is a photograph of the membrane produced in Preparation Example 2-12 of the present invention.
Figure 39 (a) is a wool, (b) is a photograph of the membrane produced in Preparation Example 2-13 of the present invention using the wool of (a).
40 is a SEM image of a membrane prepared using 50 nm wool ((a) and (b)) and 1.0 μm wool ((c) and (d)) according to Preparation Example 2-13.

The present invention includes a porous substrate layer and a CNT/chitosan nanohybrid coating layer coated on the porous substrate layer, wherein the CNT/chitosan nanohybrid has a CNT core surrounded by a chitosan shell, and the porous substrate is an organic porous substrate, an inorganic porous substrate Or a combination thereof, and the organic porous substrate is selected from the group consisting of cotton, wool, cellulose, methylcellulose, carboxymethylcellulose, polystyrene, polyethylene, polyurethane, polyacetate, and nylon. The inorganic porous substrate relates to a membrane, which is selected from the group consisting of carbon fibers, ceramics and silicates.

In the membrane of the present invention, the CNT/chitosan nanohybrid has a core/shell structure, and refers to nanoparticles having a CNT core surrounded by a chitosan shell. When CNT and chitosan are simply mixed or used in the form of a composite material, CNTs cannot be uniformly distributed and sometimes concentrated in some areas, which weakens the mechanical strength of the entire membrane and adversely affects the electrical conductivity of the membrane. Can go crazy. On the other hand, the core/shell structure of the present invention allows CNTs to be uniformly distributed, so that the membrane of the present invention can contain a high content of CNTs, while maintaining excellent mechanical strength. The core/shell structure of the CNT/chitosan nanohybrid of the present invention is shown in FIG. 1.

In the present invention, the CNT is an abbreviation for carbon nanotubes, and includes both single-walled carbon nanotubes and multi-walled carbon nanotubes. The chitosan refers to a polymer compound that deacetalized chitin, the degree of deacetylation may be 75 to 85%, and the molecular weight may be 50000 to 190000 Da, but within a range capable of achieving the object of the present invention Ramen is not limited to this.

In the membrane of the present invention, the porous substrate is a natural material consisting of cotton, wool, cellulose, methylcellulose and carboxymethylcellulose; And synthetic materials made of polystyrene, polyethylene, polyurethane, polyacetate, nylon, carbon fiber, ceramic, and silicate; and the CNT/chitosan nanohybrid may be coated. Preferably, the porous substrate may be the natural material.

In the membrane of the present invention, when the porous substrate is polyurethane, it may be in the form of a fiber or a sponge, and the pore size is preferably 50 to 500 μm, and particularly preferably 100 to 200 μm. If the size of the pores is smaller than this, the coating layer is difficult to be coated properly, and at the same time, the air passing rate is slowed, resulting in a large differential pressure, and the efficiency of removing fine dust may be deteriorated. In addition, when the pore size is larger than this, the mechanical stability of the porous substrate is deteriorated, and the air passage path may be relatively short. When the porous substrate is polyurethane, the porosity is preferably 60 to 99.9%, particularly preferably 70 to 96%, and most preferably 94 to 96%.

When the porous substrate is cotton, the pore size is preferably 50 to 500 μm. If the size of the pores is smaller than this, the coating layer is difficult to be coated properly, and at the same time, the air passing rate is slowed, resulting in a large differential pressure, and the efficiency of removing fine dust may be deteriorated. In addition, when the pore size is larger than this, the mechanical stability of the porous substrate is deteriorated, and the air passage path may be relatively short. In this case, the porosity is preferably 60 to 99.9%, particularly preferably 70 to 95%, and most preferably 92 to 95%.

When the porous substrate is wool, the size of the pores is preferably 20 to 500 μm. If the size of the pores is smaller than this, the coating layer is difficult to be coated properly, and at the same time, the air passing rate is slowed, resulting in a large differential pressure, and the efficiency of removing fine dust may be deteriorated. In addition, when the pore size is larger than this, the mechanical stability of the porous substrate is deteriorated, and the air passage path may be relatively short. In this case, the porosity is preferably 60 to 99.9%, particularly preferably 70 to 95%, and most preferably 92 to 95%.

When the porous substrate is carbon fiber, the pore size is preferably 20 to 200 μm, and particularly preferably 40 to 50 μm. If the size of the pores is smaller than this, the coating layer is difficult to be coated properly, and at the same time, the air passing rate is slowed, resulting in a large differential pressure, and the efficiency of removing fine dust may be deteriorated. In addition, when the pore size is larger than this, the mechanical stability of the porous substrate is deteriorated, and the air passage path may be relatively short. In this case, the porosity is preferably 60 to 99.9%, particularly preferably 70 to 95%, and most preferably 92 to 95%.

When the CNT/chitosan nanohybrid is prepared by coating on a porous substrate, the path through which air including fine dust passes is greatly increased by coating the CNT/chitosan nanohybrid inside the pores. In addition, the porous substrate imparts structural stability to the membrane and is easy to deform, so that it can be applied to various types of electrostatic dust collection systems.

In the membrane of the present invention, it is preferable that the coating layer contains CNTs in an amount of 25 to 90% by weight based on the total weight of the coating layer. If the CNT content is less than this, the electrical conductivity of the membrane is poor, and thus it is not suitable for use in the electrostatic dust collection system. If it is more than this, the mechanical strength of the membrane may be weakened.

In the membrane of the present invention, it is preferable that the coating layer has an electrical resistance of 5 Ω or less. If the electrical resistance is greater than this, a high voltage is required to generate an electric field, and thus there is a problem in that the energy efficiency of the electrostatic dust collection system is lowered.

In the membrane of the present invention, when the porous base layer comprises cotton or wool, the coating layer is preferably coated at a weight of 1 to 5 times based on the weight of the porous base layer, and particularly preferably 2 to 3.5 times. . When the porous base layer comprises carbon fibers, the coating layer is preferably coated at a weight of 0.5 to 2 times based on the weight of the porous base layer, and particularly preferably 0.5 to 1 times. When the weight of the coating layer is less than this, the dust collecting ability of the electrostatic dust collecting system is lowered, and when it is more than this, the structural stability and porosity of the membrane are lowered, and the differential pressure may be increased.

In the membrane of the present invention, it is preferable that the coating layer has a specific surface area of 50 to 150 m ² /g. If the specific surface area is less than this, the dust collecting capacity of the electrostatic precipitating system decreases, and if it is larger, the structural stability of the membrane may deteriorate.

In addition, the present invention is the membrane layer; And a filtration layer.

In the electrostatic dust collection system of the present invention, the filtration layer refers to a layer having a function of filtering dust on a filtration principle, and may include a general cloth, cabin filter, nonwoven fabric, or wool layer.

The general fabric collectively refers to woven and knitted fabrics composed of fibers.

In the electrostatic dust collection system of the present invention, the membrane layer may be disposed on both sides or one side of the filtration layer. The simplification of the electrostatic dust collection system when the membrane layer is disposed on one side of the filtration layer is shown in FIG. 2, and the simplification of the electrostatic dust collection system when the membrane layer is disposed on both sides of the filtration layer is It is as in FIG. 3.

In FIG. 2, air containing dust is introduced vertically into one membrane layer through a filtration layer. The dust of the introduced air passes through the pores and is collected on the membrane surface due to the attraction by the electric field generated in the membrane layer by an external power source, and the dust-removed air passes through the filtration layer and is discharged outside the dust collection system.

In FIG. 3, air containing dust passes between the filtration layer and the membrane layers on both sides in a horizontal direction. The dust of the air introduced due to the attraction by the electric field generated in the membrane layer by the external power source is attracted to the pores of the membrane layer surrounding the filter layer, and the dust-removed air passes through the filter layer to pass outside the dust collection system. Is discharged.

The electrostatic dust collection system of the present invention may have a planar shape or a cylindrical shape, and a typical example of the planar shape is as shown in FIG. 2 above. Can be configured. In addition to the cylindrical and planar shapes, any form that can utilize the principle of the electrostatic dust collection system of the present invention can be applied without limitation.

The electrostatic dust collection system of the present invention preferably has an electrical resistance of 100 Ω or less when the porous base layer contains polyurethane, and 50 Ω or less when the porous base layer contains carbon fibers. When the electrical resistance is greater than this, a high voltage is required to generate an electric field required for driving the dust collection system, and energy efficiency of the electrostatic dust collection system is deteriorated.

In the electrostatic dust collection system of the present invention, it is preferable that the wind speed of the gas passing through the filtration layer is 0.001 to 5 m/s. If the wind speed is lower than this, the amount of air to be purified per unit time is insufficient, and if it is higher than this, there is a problem in that the dust collection performance is insufficient.

In the electrostatic dust collection system of the present invention, it is preferable that the differential pressure before and after passing through the filtration layer is 100 Pa or less, and if the differential pressure is greater than this, there is a problem that the dust collection efficiency is insufficient.

Example

Hereinafter, preferred manufacturing examples and experimental examples are provided to help understanding of the present invention. However, the following Preparation Examples and Experimental Examples are provided only for easier understanding of the present invention, and the contents of the present invention are not limited by the Preparation Examples and Experimental Examples. When the CNT content of the membrane in the manufacturing example of the present invention is x% by weight, it is called CNT-chitosan x.

Example 1. CNT/chitosan nano hybrid coating layer

material

Multi-walled carbon nanotubes (>95%, outer radius 20-30 nm, length 10-30 μm) were obtained from EMP (EM-Power Co., Republic of Korea) and used. Low molecular weight chitosan (MW = 50000-190000, deacetylation of 75-85%) was purchased from Sigma-Aldrich (United States) and used. All chemicals including glacial acetic acid, sodium hydroxide and organic solvent were purchased from Sigma-Aldrich and used without further purification.

Production Example 1-1. Preparation of CNT-chitosan 50 membrane

Prior to the use of carbon nanotubes (CNT), all possible impurities were removed by refluxing with 5N hydrochloric acid for one day. Thereafter, 200 mg of chitosan was dissolved in 50 mL (pH <2) of a 1:1 mixture of 5N hydrochloric acid and glacial acetic acid for 24 hours. Then, 200 mg of CNT was added to the chitosan solution and homogenized with a high pressure homogenizer (Nano DeBEE 45-3, BEE International, South Easton MA). Thereafter, 2N sodium hydroxide was added to the acidic CNT-chitosan solution to neutralize it slowly, and a small molecule containing inorganic by-products was dialyzed for 3 days with a dialysis membrane (Spectrum Laboratories, Savannah, GA) having a segment having a molecular weight of 12000 to 14000 and distilled water. Were removed. The CNT-chitosan solution was placed in an appropriately sized container, sonicated for 30 minutes, and placed for 2 days at a fume hood and room temperature. Thereafter, the solution was dried to prepare a membrane.

Production Example 1-2. Preparation of CNT-chitosan 25 membrane

Membranes were prepared using the same method as in Production Example 1, except that 25% by weight of the carbon nanotubes was used.

Preparation Example 1-3. Preparation of CNT-chitosan 75 membrane

Membranes were prepared using the same method as in Production Example 1, except that 75% by weight of the carbon nanotubes was used.

Production Example 1-4. Preparation of CNT-chitosan 85 membrane

Membranes were prepared using the same method as in Production Example 1, except that 85% by weight of the carbon nanotubes was used.

Production Example 1-5. Preparation of CNT-chitosan 60 membrane

Membranes were prepared using the same method as in Production Example 1, except that 60% by weight of the carbon nanotubes was used.

Preparation Example 1-6. Preparation of CNT-chitosan 70 membrane

Membranes were prepared using the same method as in Production Example 1, except that 70% by weight of the carbon nanotubes was used.

Production Example 1-7. Preparation of CNT-chitosan 80 membrane

Membranes were prepared using the same method as in Production Example 1, except that 80% by weight of the carbon nanotubes was used.

Preparation Example 1-8. Preparation of CNT-chitosan 90 membrane

Membranes were prepared using the same method as in Production Example 1, except that 90% by weight of the carbon nanotubes was used.

Experimental Example 1-1. Morphological analysis of CNT-chitosan membrane

The morphology of the CNT-chitosan membrane was analyzed using a high resolution electron transmission microscope (HR-TEM; JEM 3010, JEOL, Japan) and a field emission scanning electron microscope (FE-SEM; MIRA II LMH microscope, Tescan, Czech Republic). . Samples were sputter-coated with gold prior to SEM analysis. The results are shown in FIGS. 4 to 6. Figure 4 is an HR-TEM (A), FE-SEM (B) images and pictures (C) of CNT-chitosan 50. 5 is an enlarged view of C of FIG. 4 by SEM. 6 is an HR-TEM image of CNT-chitosan 25, 50, 75 and pure CNT.

Experimental Example 1-2. Characterization of CNT-chitosan membrane

To characterize the CNT-chitosan membrane, a thermogravimetric analyzer (TGA; Seiko Exstar 6000 TG/DTA6100, Japan) and a Fourier transform infrared spectroscopy (FTIR; JASCO 470 PLUS, Japan) were used. A sample of 4 mg was used to heat the sample in the range of 25 to 900°C at a rate of 10°C/min. The FT-IR spectrum was measured in the solid state and in the range of 400 to 4000 cm ^-1 . For comparison, experiments were also performed on pure chitosan and CNT, and the results of FT-IR are shown in FIG. 7 and the results of TGA are shown in FIG. 8.

In the case of FT-IR, pure CNT showed no characteristic peaks. This is because there are no functional groups on the surface. On the other hand, the 50% by weight CNT-chitosan membrane showed a peak below that of the same type as chitosan.

-3120-3385 cm ^-1 (stretching of -OH and -NH from chitosan)

-2925 and 2856 cm ^-1 (stretching of -CH in chitosan)

-1654 cm ^-1 (C=C stretch of pure CNT)

-1632 cm ^-1 (C=O increase in chitosan)

This IR spectrum indicates that CNT was functionalized well with chitosan.

In the case of thermogravimetric analysis, the main mass loss occurred in the range of 600 to 700°C in the case of pure CNT, but in the case of pure chitosan, mass loss occurred in two steps. The first step is a step in the vicinity of about 300°C in which the polymer structure is broken and the decomposition of glucosamine units occurs, and the second step is in the range of 400 to 600°C in which oxidative decomposition occurs. The CNT-chitosan membrane of 50% by weight showed a clear two-step decomposition. The first step is a step of 200 to 300° C. resulting from the loss of chitosan, and the second step is a step of 500 to 600° C. where CNT decomposition occurs. The thermal decomposition temperature of both materials shifted to the lower side compared to the pure case. This is because the weight concentration of each component is half lower compared to the pure case.

Experimental Example 1-3. Mechanical properties analysis of CNT-chitosan membrane

For each CNT-chitosan membrane, the thickness of the surface chitosan, electrical resistance, tensile strength, modulus of elasticity, and elongation were measured. For comparison, pure chitosan was also measured. The results are shown in Table 1 below.

sample Chitosan thickness (nm) Sheet resistance (Ω/sq) Tensile strength (MPa) Elastic modulus (N/mm) Elongation (%) Chitosan ND >10¹² 14.814±1.433 5.501±1.367 217.2±21.113 CNT-chitosan 25 6.528±1.0788 16.51±0.651 37.557±1.678 16.253±2.068 76.3±6.472 CNT-chitosan 50 3.542±0.1906 8.477±0.377 51.039±1.104 22.754±2.128 67.1±4.359 CNT-chitosan 75 1.211±0.1172 5.133±0.068 36.113±1.772 27.263±1.115 40.7±5.669 CNT-chitosan 85 ND 4.861±0.128 14.251±1.839 24.02±2.029 13.3±1.115

(ND means value is not determined)

FIG. 9 shows a comparison of the change in chitosan thickness and resistance according to the CNT content, and a comparison of tensile strength and elastic modulus. In addition, a graph showing that the elongation rate changes according to the CNT content is shown in FIG. 10.

In addition, tensile-stress curves were obtained for each membrane and chitosan. The results are shown in FIG. 11.

Experimental Example 1-4. Surface analysis of CNT-chitosan membrane

Raman spectrum (Horiba LabRam Aramis IR2, Japan) and X-ray photoelectron spectroscopy (XPS; AES-XPS ESCA 2000, Thermo Fisher Scientific, United States) were used to analyze the surface of the CNT-chitosan membrane. The results are shown in Fig. 12 (Raman spectrum) and Fig. 13 (XPS).

The Raman spectrum is an efficient method for analyzing carbon nanocomponents. The D-band at 1350 cm ^-1 shows the presence of sp³ hybrid carbon. It is also concerned with disordered graphite structures proportional to the amount of amorphous carbon in the dispersed state. The high frequency 1580 cm ^-1 G-band shows the structural strength of sp² hybrid carbon according to the vibration mode of CNT. The sharpness of the G and G` peaks has to do with the fact that the nanotubes will be able to show metal-like conductivity.

The XPS shows three characteristic peaks.

-284.60eV (C 1s)

-399.63-400.16eV (N 1s)

-532.36-533.17eV (O 1s)

C 1s, N 1s and O 1s of XPS data obtained from functionalized CNTs represent the binding energies of 280-295, 395-410, and 525-540eV, respectively. The C 1s spectrum of the chitosan functionalized CNT shows that the sp² carbon atom of the CNT molecule strongly attached to the chitosan molecule is present in a large amount. These XPS data show that the CNT surface is well functionalized with chitosan.

Experimental Example 1-5. Fine dust removal test of CNT-chitosan 50 membrane

The surface of the membrane when exposed to external air for 3 hours under a voltage of 0 to 12 V was observed with a SEM image to qualitatively grasp the degree of adsorption of fine dust. In case of 0V, in Fig. 14, in case of 3V, in Fig. 15, in case of 6V, in Figs. 16, and 9V, in Figs. Did. From this, it was confirmed that as the voltage increased and a strong electric field was generated, the surface of the membrane was covered with fine dust.

Example 2. Membrane comprising porous substrate layer and CNT/chitosan nano hybrid coating layer and electrostatic dust collection system using same

Production Example 2-1. Preparation of membrane comprising polyurethane sponge layer and CNT/chitosan nano hybrid coating layer (CNT-chitosan 50)

Chitosan was dissolved in 150 ml of 1% acetic acid and hydrochloric acid solution (pH 2.0), and CNT was added, followed by sufficient stirring. A solution of chitosan 0.7g and CNT 0.7g was prepared and sufficiently dispersed through agitation and dispersion equipment. Then, 5% ammonia water or a basic solution was added to each solution to slowly increase the pH to 9-10.

The solution prepared above was diluted in half and stirred sufficiently, so that the polyurethane sponge was completely immersed in the diluted solution so that the solution was sufficiently absorbed. Thereafter, the mixture was dried in a 70° C. oven, dried completely, and then the process was repeated 3 to 7 times. Finally, after washing with water and ethanol, drying, the membrane comprising a polyurethane sponge layer and a CNT/chitosan nano hybrid coating layer was dried. Was prepared, and it is called "CNT Coated U-Sponge". The surface of the prepared CNT Coated U-Sponge and a SEM image of the enlarged surface are shown in FIG. 20. It can be seen from FIG. 20 that the CNT/chitosan nano hybrid was coated on the polyurethane pore surface. In addition, the resistance value and weight according to the number of coatings were measured, and this is shown in Table 2 below.

Coating count Resistance (Ω) Weight (g) 0 Measure X 0.539±0.032 One 876.6±101.35 0.813±0.016 2 292.8±70.92 1.071±0.026 3 131.6±17.46 1.372±0.006 4 133.8±38.45 1.639±0.015 5 131.4±10.24 1.894±0.023 6 130.6±12.95 2.196±0.009 7 130.6±8.29 2.451±0.024

From Table 2, it was confirmed that even if the number of coatings increased, the resistance did not drop to a value lower than 130 Ω.

Production Example 2-2. Preparation of membrane comprising a polyurethane fiber layer and a CNT/chitosan nano hybrid coating layer (CNT-chitosan 50)

After preparing the solution in the same manner as in Preparation Example 2-1, a polyurethane fiber layer and a membrane including a CNT/chitosan nano-hybrid coating layer were prepared using polyurethane fibers instead of polyurethane sponges, which were prepared as "CNT Coated U- Fiber". The surface of the prepared CNT Coated U-Fiber and an SEM image enlarging the same are shown in FIG. 21. It can be seen from FIG. 21 that the CNT/chitosan nano hybrid was coated on the polyurethane pore surface. In addition, the resistance value and weight according to the number of coatings were measured, and this is shown in Table 3 below.

Coating count Resistance (Ω) Weight (g) 0 Measure X 1.389±0.008 One 1437.6±126.41 1.476±0.007 2 488±133.15 1.554±0.006 3 159.2±86.93 1.659±0.003 4 147±32.17 1.759±0.009 5 131.8±19.27 1.865±0.004 6 132±8.34 1.967±0.007 7 130.8±18.90 2.062±0.017

Production Example 2-3. Preparation of membrane comprising carbon fiber layer and CNT/chitosan nano hybrid coating layer (CNT-chitosan 50)

After preparing the solution in the same manner as in Preparation Example 2-1, a carbon fiber layer and a membrane including a CNT/chitosan nano hybrid coating layer were prepared using carbon fiber instead of a polyurethane sponge, and a “CNT Coated C-Fiber” was prepared. It is called. The surface of the prepared CNT Coated C-Fiber and an SEM image of the enlarged surface are shown in FIG. 22. It can be seen from FIG. 22 that the CNT/chitosan nano hybrid was coated on the surface of the carbon fiber pores.

Production Example 2-4. Fabrication and removal rate measurement of cylindrical electrostatic dust collection system

To apply the CNT Coated U-Sponge membrane prepared in Preparation Example 2-1 to an air purifier and a building vent, a cylindrical electrostatic dust collection system was manufactured. The cabin filter was used as a filtration filter, and cloth/Al/CNT Coated U-Sponge rolls were prepared as shown in FIG. 23, and the fine dust removal rate was measured under 1A conditions using the same. The results are shown in FIG. 24.

Overall, the removal rate was significantly increased by the CNT Coated U-Sponge membrane, especially the removal rate of PM 2.5 and 1.0 dust. The PM 1.0, 2.5 and 10 dust refers to dust having a particle diameter of 1, 2.5 and 10 μm or less, respectively.

Production Example 2-5. Preparation of planar electrostatic dust collection system using CNT Coated U-Sponge membrane

A planar electrostatic dust collection system was fabricated by combining a cabin filter with the CNT Coated U-Sponge membrane prepared in Preparation Example 2-1. Cabin filter was used as the filtration layer, and the density of CNT Coated U-Sponge was 25, 50, and 65 kg/m ³ (abbreviated as K). Used. In addition, in the case of 50K, two types of electrostatic precipitating systems were produced, with and without using an Al electrode layer for transferring micro-currents between the filtration layer and the membrane, which is simplified and illustrated in FIG. 25.

Production Example 2-6. Preparation of planar electrostatic dust collection system using CNT Coated U-Fiber membrane

In Preparation Example 2-5, a CNT Coated U-Fiber was used instead of a CNT Coated U-Sponge to prepare a planar electrostatic dust collection system. This is simplified and illustrated in FIG. 26.

Production Example 2-7. Preparation of planar electrostatic dust collection system using CNT Coated C-Fiber membrane

In Preparation Example 2-5, CNT Coated C-Fiber was used instead of CNT Coated U-Sponge, and the carbon fiber itself had excellent conductivity, so that a planar electrostatic dust collection system was prepared without using an Al electrode layer. This is simplified and illustrated in FIG. 27.

Preparation Example 2-8. Preparation of a membrane comprising a cotton layer and a CNT/chitosan nano hybrid coating layer (CNT-chitosan 50)

After preparing the solution in the same manner as in Preparation Example 2-1, a membrane including a cotton layer and a CNT/chitosan nano-hybrid coating layer was prepared using cotton fibers having various pore sizes instead of a polyurethane sponge, which is shown in FIG. Shown.

Production Example 2-9. Preparation of a membrane comprising a cotton layer and a CNT/chitosan nano hybrid coating layer (CNT-chitosan 60)

A membrane including a cotton layer and a CNT/chitosan nano hybrid coating layer was prepared in the same manner as in Preparation Example 2-8, and this is illustrated in FIG. 35.

Preparation Example 2-10. Preparation of a membrane comprising a cotton layer and a CNT/chitosan nano hybrid coating layer (CNT-chitosan 70)

A membrane including a cotton layer and a CNT/chitosan nanohybrid coating layer was prepared in the same manner as in Preparation Example 2-8, and this is illustrated in FIG. 36.

Production Example 2-11. Preparation of a membrane comprising a cotton layer and a CNT/chitosan nano hybrid coating layer (CNT-chitosan 80)

A membrane including a cotton layer and a CNT/chitosan nano hybrid coating layer was prepared in the same manner as in Preparation Example 2-8, and this is illustrated in FIG. 37.

Production Example 2-12. Preparation of a membrane comprising a cotton layer and a CNT/chitosan nano hybrid coating layer (CNT-chitosan 80)

A membrane including a cotton layer and a CNT/chitosan nanohybrid coating layer was prepared in the same manner as in Preparation Example 2-8, and this is illustrated in FIG. 38.

Production Example 2-13. Preparation of membrane comprising wool layer and CNT/chitosan nano hybrid coating layer (CNT-chitosan 90)

In the same manner as in Preparation Example 2-1, a membrane including a wool layer and a CNT/chitosan nano hybrid coating layer was prepared using 50 nm and 1.0 μm wool layers, respectively, and shown in FIGS. 39 and 40.

Experimental Example 2-1. Measurement of fine dust removal rate by planar electrostatic dust collection system of Preparation Example 2-5

The fine dust removal rate of the planar electrostatic dust collection system of Preparation Example 2-5 was measured, and an experiment was performed under 9V voltage. The case of using only the cabin filter without the membrane of the present invention was used as a control, and the results of using 25K as the density are shown in FIGS. 28 and 50K as shown in FIGS. 29 and 65K in FIG. In the case of the expression dust collection system, the results are shown in FIG. 31.

In the case of using only the cabin filter, on average, PM 10 was about 75%, PM 2.5 was about 65%, PM 1.0 was about 57%, and when 25K CNT Coated U-Sponge membrane was added, PM 10 was 80%. , PM 2.5 was 77%, PM 1.0 was 64% removal rate was confirmed that the removal rate is increased. Even when 50K and 65K CNT Coated U-Sponge membranes were added, all of the fine dust removal rates increased, especially at 50K, PM 10 was 97%, PM 2.5 was 78%, and PM 1.0 was 68%, the highest removal rate. . When the Al electrode layer was added in addition to the 50K CNT Coated U-Sponge, the removal rate of PM 10 was 94%, PM 2.5 was 83%, and PM 1.0 was 75%, and the removal rate of PM 10 was not increased by the addition of the electrode layer. It was confirmed that the dust removal rates of PM 2.5 and 1.0, which correspond to ultra fine dust, significantly increased.

Experimental Example 2-2. Measurement of fine dust removal rate by planar electrostatic dust collection system of Preparation Example 2-6

The removal rate of fine dust was measured for the planar electrostatic dust collection system of Preparation Example 2-6, and an experiment was performed under 9V voltage. The resulting rolls are shown in Figure 32. When only the cabin filter was used, PM 10 was 80%, PM 2.5 was 65%, and PM 1.0 was 58%. When CNT Coated U-Fiber membrane was added, PM 10 was 93%, PM 2.5 was 80%, PM 1.0 showed a removal rate of 69%. Overall, the removal rate increased, and the removal rate for PM 2.5 and 1.0 dust increased by 10 to 15%.

Experimental Example 2-3. Measurement of fine dust removal rate by planar electrostatic dust collection system of Preparation Example 2-7

The fine dust removal rate was measured for the planar electrostatic dust collection system of Preparation Example 2-7, and an experiment was performed under a 9V voltage. The resulting rolls are shown in Figure 33. When only the cabin filter was used, PM 10 was 79%, PM 2.5 was 65%, PM 1.0 was 57%, and when a CNT Coated C-Fiber membrane was added, PM 10 was 97%, PM 2.5 was 83%, PM 1.0 showed a removal rate of 75%. Overall, the removal rate increased, and the removal rate for PM 2.5 and 1.0 dust increased by about 20%.

1, 1': void
2, 2': coating layer
3: filtration layer
4: Air passage direction

Claims (16)

A porous substrate layer and a CNT/chitosan nano hybrid coating layer coated on the porous substrate layer,
In the CNT/chitosan nano hybrid, the CNT core is surrounded by a chitosan shell,
The porous substrate is a membrane selected from the group consisting of cotton, wool, cellulose, methylcellulose, carboxymethylcellulose, polystyrene, polyethylene, polyurethane, polyacetate, nylon, carbon fiber, ceramic and silicate. The membrane of claim 1, wherein the porous substrate is cotton in the form of fibers or sponges. The membrane according to claim 2, wherein the cotton in the form of a fiber or a sponge has a pore size of 50 to 500 μm. The membrane of claim 1, wherein the porous substrate is a fiber or sponge-shaped wool. The membrane according to claim 4, wherein the wool in the form of fibers or sponges has a pore size of 20 to 200 μm. The membrane of claim 1, wherein the coating layer comprises 25 to 90% by weight of cotton or wool based on the total weight of the coating layer. The membrane of claim 1, wherein the coating layer has an electrical resistance of 5 Ω or less. The membrane of claim 2, wherein the coating layer is coated with a weight of 1 to 5 times based on the weight of the cotton or wool layer. The membrane of claim 1, wherein the coating layer has a specific surface area of 50 to 150 m ² /g. The membrane layer according to claim 1; And a filtration layer. The electrostatic dust collection system according to claim 10, wherein the filtration layer is selected from the group consisting of a general cloth, a cabin filter, a nonwoven fabric, and wool. The electrostatic dust collection system according to claim 10, wherein a membrane layer is disposed on both sides or one side of the filtration layer. The electrostatic dust collection system according to claim 10, which has a flat or cylindrical shape. The electrostatic dust collection system according to claim 10, which has an electrical resistance of 100 Ω or less. The electrostatic dust collection system according to claim 10, wherein the air velocity of the gas passing through the filtration layer is 0.001 to 5 m/s. The electrostatic dust collection system according to claim 10, wherein the differential pressure before and after passing through the filtration layer is 100 Pa or less.

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