KR20160131301A

KR20160131301A - Ultrafine fiber-based filter with super-flux and high filtration efficiency and preparation method thereof

Info

Publication number: KR20160131301A
Application number: KR1020150063335A
Authority: KR
Inventors: 조성무; 이성호; 조한익; 박세준
Original assignee: 한국과학기술연구원
Priority date: 2015-05-06
Filing date: 2015-05-06
Publication date: 2016-11-16
Also published as: KR101691636B1

Abstract

An ultrafine fiber-based filter has high permeability in which water permeability is more than or equal to 7,500 L/hr.m2 at 2.5 psi pressure. Filtration efficiency of 200 nm particle is more than or equal to 98% or the ultrafine fiber-based filter has high permeability in which water permeability is more than or equal to1,000 L/hr.m2 at 2.5 psi pressure. Filtration efficiency of 100 nm particle is more than or equal to 98%. The ultrafine fiber-based filter has superior water permeability and particle removing performance in comparison with a membrane filter for filtering existing bacteria and can absorb and remove microparticles such as a virus or the like while having excellent water permeability.

Description

TECHNICAL FIELD [0001] The present invention relates to an ultrafine fibrous filter having a high permeation flow rate and a high filtration efficiency, and a method of manufacturing the same. [0002]

An ultrafine fibrous filter having a high permeation flow rate and a high filtration efficiency and a method for manufacturing the same are provided.

In a water purification system, membrane filters are commonly used to separate fine particles by membranes with pores smaller than the particles to be filtered. Examples of the membrane filter include microfiltration (MF) (pore size 50 to 2000 nm), ultrafiltration (UF) (pore size 1 to 200 nm), reverse osmosis (RO) 2 nm). Such membrane-based liquid filters and separation techniques are useful in water treatment applications such as emulsion separation of oil and water or desalination. However, when very fine particles such as viruses are to be removed, the pressure loss is very high due to the small pores, the permeation rate is low due to low permeability, and the pore of the membrane is closed during use, so that the permeation rate can be drastically reduced. In addition, since frequent backwashing is required, removal of impurities is limited by various temperature applications, the energy consumption is large, the separator material itself is not strong, and the separator may be destroyed or the pore may become large.

On the other hand, conventional fiber filters have low filtration accuracy and can not remove viruses in water, and therefore, they are difficult to be used for water treatment microfiltration. For example, in the case of melt-blown nonwoven fabrics that are commonly applied to current filters, such nonwoven fabrics can not filter nano-sized particles, such as viruses, due to the large diameter of the constituent fibers. In addition, when a polymer blend fiber is produced by a melt blowing method and a microfine fiber having a diameter distribution of 5 to 500 nm is produced by removing the sea component, large pores are formed due to the mixing of large diameter fibers, Viruses and the like can not be removed.

To improve this, JP-A-2008-136896 discloses a water treatment filter made of paper by cutting ultrafine fibers obtained by extruding with a polymer blend. However, since the nanofibers are prepared by blending the nanofibers with a blend, and then the nanofibers are cut to a size of about 2 mm, the filter layer made of paper is prepared by the initial method, and the process is complicated and expensive.

Japanese Patent Application Laid-Open No. 2009-148748 discloses a filter in which polymer nanofibers are coated on an existing nonwoven fabric by electrospinning. The electrospinning method can produce microfibers having a fiber diameter of 1 to 500 nm, which enables removal of fine materials that can not be obtained with conventional fiber filters, and the operating pressure is significantly lower than that of a microfiltration filter using a porous membrane . However, in the electrospinning method, it is difficult to produce a filter having a pore size capable of filtering ultrafine particles such as viruses, and since a pore size is too small, a high operating pressure is required and the filtration efficiency is increased And the permeate flow rate may be very low. In addition, when the filtration layer is made only of a polymer material, the applicable temperature range is limited due to the thermal stability maintenance condition, and since the pore size depends only on the nanofiber diameter, it is difficult to produce a filter satisfying both high filtration efficiency and high permeation flow rate .

Accordingly, the present inventors have found that an ultrafine fibrous filter manufactured by electrospinning using a solution of a polymer solution, a sol-gel solution of a ceramic precursor, and a sol-gel solution of a polymer and a ceramic precursor as a spinning solution, The filtration efficiency of the 200 nm particle is 98% or more, or the permeation flow rate is at least 1,000 L / hr.m ² , while the permeation flow rate is at least 7,500 L / hr.m ² , Ultrafine fiber filter satisfying both high filtration efficiency / high permeation flow rate with filtration efficiency of 98% or more is manufactured.

Accordingly, it is an object of the present invention to provide a filtration device capable of removing microfine particles such as bacteria, ultrafine fibrous filters having higher filtration efficiency and ultrafine particles such as viruses, The present invention provides an ultrafine fibrous filter having high filtration efficiency and low pressure loss during filtration to exhibit a high permeate flow rate.

In addition, an embodiment of the present invention provides a method of manufacturing the fibrous filter.

Embodiments according to the present invention can be used to accomplish other tasks not specifically mentioned other than the above-described tasks.

The filter according to an embodiment of the present invention is manufactured by electrospinning using a solution of a polymer solution, a sol-gel solution of a ceramic precursor, a solution of a polymer and a sol-gel solution of a ceramic precursor as a spinning solution, The filtration efficiency of the 200 nm particles is 98% or more, or the permeation flow rate is at least 1,000 L / hr.m ² , while the water permeation flow rate at the pressure has a high permeation flow rate of at least 7,500 L / hr.m ² , nm ultrafine fibrous filter having a high filtration efficiency / high permeation flow rate with a filtration efficiency of 98% or higher.

The microfine fibers constituting the filter according to an embodiment of the present invention may be microfine fibers having an average fiber diameter of 100 nm or less or microfine fibers having a fiber average diameter of 100 nm or less and microfine fibers having an average fiber diameter of 100 nm or more And a high filtration efficiency / high permeation flow rate.

In one embodiment of the present invention, the filter is formed by mixing a filtration layer with a polymer solution, a sol-gel solution of a ceramic precursor, and a sol-gel solution of a polymer and a ceramic precursor, thereby forming bacteria, heavy metals, The membrane filter of the present invention has a superior filtration efficiency that can be removed and has a low pressure loss during filtration and thus shows a much higher permeate flow than the membrane filter of the related art or the prior art filter manufactured by electrospinning and is useful as an air and water treatment filter Can be used.

FIG. 1 is a scanning electron microscope (SEM) photograph of a conventional ultrafine fibrous filter having a fiber diameter produced by electrospinning according to Comparative Examples 1 and 2 in a monodispersed state, and a small photograph of FIG. - Transmission electron microscope (TEM) photograph showing core shell structure
2 is a scanning electron micrograph of a polyvinylidene fluoride / meta-aramid composite ultrafine fibrous filter showing the distribution of the diameter of the dispersed fibers according to Example 1. Fig.
3 is a scanning electron micrograph of a silica composite polyvinylidene fluoride ultrafine fibrous filter showing the distribution of the diameter of the dispersed fibers according to Example 2. Fig.
4 is a scanning electron micrograph of a polyvinylidene fluoride ultrafine fibrous filter showing the distribution of the diameter of the dispersed fibers according to Example 3. Fig.
5 is a scanning electron micrograph of a polyvinylidene fluoride ultrafine fibrous filter showing the distribution of the diameter of the dispersed fibers according to Example 4
6 is a scanning electron micrograph of a polyacrylonitrile ultrafine fibrous filter showing the distribution of the diameter of the dispersed fibers according to Example 5
7 is a scanning electron micrograph of a polyethersulfone (PES) ultrafine filament filter showing the distribution of the dispersed fiber diameter according to Example 6
8 is a photograph of an m-aramid ultrafine polymeric filament filter showing the distribution of the diameter of the dispersed fibers according to Example 7
9 is a scanning electron micrograph of a zirconia / PVdF composite ultrafine filament filter according to Example 8

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same reference numerals are used for the same or similar components throughout the specification. In the case of publicly known technologies, a detailed description thereof will be omitted.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

One embodiment of the present invention relates to a method for producing a microfine fiber, comprising the steps of: preparing a microfine fiber constituted by a polymer solution, a sol-gel solution of a ceramic precursor, and a sol-gel solution of a polymer and a ceramic precursor as a spinning solution, Is composed of a group of microfine fibers having a diameter of 100 nm or less or a group of microfine fibers having an average fiber diameter of 100 nm or less and a group of microfine fibers having a fiber average diameter of 100 nm or more.

Ultrafine fibrous filters with high permeation flow rate and high filtration efficiency have a high permeation flux of at least 7,500 L / hr.m ² at a water permeation rate of 2.5 psi, a filtration efficiency of at least 98% of 200 nm particles, It has a high permeation flow rate of 1,000 L / hr.m ² or more and filtration efficiency of 100 nm particles is 98% or more.

The ultrafine fibrous porous material constituting the ultrafine fibrous filter according to an embodiment of the present invention is prepared by electrospinning a solution of a polymer solution, a sol-gel solution of a ceramic precursor, and a sol-gel solution of a polymer and a ceramic precursor. The ultrafine polymeric fibrous porous article according to one embodiment of the present invention is in the form of a porous article in which ultrafine fibers produced by electrospinning appear and are randomly arranged and accumulated continuously. However, in an embodiment of the present invention, in the ultrafine fibrous filter having a high permeation flow rate and high filtration efficiency, the ultrafine fiber group having an average fiber diameter of 100 nm or less and the ultrafine fiber group having an average fiber diameter of 100 nm or more are mixed Or a layer made of ultrafine fibers having an average fiber diameter of 100 nm or less and an ultrafine fiber layer having an average fiber diameter of 100 nm or more are alternately stacked.

The microfine fiber group having an average fiber diameter of 100 nm or less has an average fiber diameter of 50 to 100 nm (preferably 70 to 100 nm) and an average fiber diameter of 1 to 50 nm 10 to 30 nm) is provided.

The ceramic precursor used to produce the polymeric fibrous filter of an embodiment of the present invention may be a silica precursor or an alumina precursor. For example, the ceramic precursors are M (OR) x, MRx (OR) y, is represented by MXy or M (NO ₃₎ y, wherein M is Si, Al, or Zr, R is C ₁ -C ₁₀ alkyl group X is F, Cl, Br or I, x is an integer of 1 to 4, and y is an integer of 1 to 4. Use of a mixture of a ceramic precursor or a mixture thereof with a polymer is used to increase the heat resistance of the ultrafine microfine fibers formed. In addition, the surface of the fibers constituting the heat-resistant ultrafine polymeric fibrous porous body, which is a filtration layer, Thereby giving a function of collecting very fine particles. The ultrafine fibers prepared by electrospinning of the ceramic precursor / polymer mixture according to an embodiment of the present invention are characterized in that the surface structure and the component thereof are the ceramic component, and the skin multi-core-shell (skin-sea type) nanostructure Unlike the fiber prepared by using the ceramic precursor alone, it has heat resistance and surface functionality, but is very flexible like a polymer fiber. Figs. 1 (a) and 9 show the ceramic skin structure and the sea-island structure.

The polymer resin used in one embodiment of the present invention is not particularly limited as long as it is a polymer used as a filter material. For example, the polymeric resin may be a polymeric fibrous material selected from polyacrylonitrile and copolymers thereof, poly (vinylidene fluoride) and its copolymers, cellulose and its derivatives, polyvinylpyrrolidone Filter.

Further, a high-heat-resistant resin including a polyamideimide, a polyetherimide, a polyimide, a polyamide (for example, para and a meta-aramid), a polyphenylene sulfone, a polysulfone, a polyether sulfone, The heat resistance can be further improved. Further, it is also possible to use a polymer having -SO ₃ H, COOH or an ionic functional group such as a water-soluble polymer including polyvinyl alcohol, polyacrylic acid, polyethylene oxide, carboxymethyl cellulose, sulfonated polyether ether ketone (SPEEK) and sulfonated polysulfone Polymer resins or copolymers thereof may also be used. The porous article produced from the polymer resin is also not melted or pyrolyzed at the melting point or thermal decomposition temperature of the polymer resin.

In the case of a polymer which is melted, has a low glass transition temperature and is thermally decomposed before melting, if fibers are formed from a solution of a ceramic precursor according to an embodiment of the present invention or a sol-gel solution of the mixture and a polymer resin, The shape stability is maintained even at a temperature much higher than the melting point or the glass transition temperature of the polymer resin, and the heat resistance is increased such that the thermal decomposition temperature is greatly increased.

Ultrafine fibers are sea-island microfine fibers composed of a more hydrophilic polymer component as a sea component and a more hydrophobic polymer component as a component when prepared from a mixed solution of polymers that are incompatible with each other. In the ultrafine fibrous filter using the sea type microfine fibers, the hydrophilic part is exposed on the fiber surface, which has a good influence on the permeation flow rate of the water treatment filter. However, there is a possibility that the water-soluble part is dissolved during repeated use. Therefore, in one embodiment of the present invention, ultrafine fibrous filter is produced by electron beam crosslinking or chemical crosslinking of microfine fiber mixed with hydrophilic polymer.

In one embodiment of the present invention, the ultrafine fibers constituting the filter to be discharged by electrospinning are ultrafine fiber groups having an average fiber diameter of 100 nm or less, or ultrafine fibers having an average fiber diameter of 100 nm or less and fibers having an average fiber diameter of 100 nm The following methods have been used to produce microfine fiber groups.

A solution of a polymer in which a metal salt including FeCl ₃ , CaCl ₂ , MgCl ₂ , NaCl, LiCl, LiNO ₃ , and Fe (NO ₃ ) ₃ is dissolved to improve the chargeability, a sol solution of a ceramic precursor, A solution of a sol-gel solution is electrospun to prepare a microfibre filter.

In addition, the microfibers having different fiber diameters are discharged by using the same spinning liquid or using different spinning nozzles, respectively. However, the discharge speed of the spinning solution and the intensity of the applied high voltage are different from each other Thereby obtaining ultrafine fibrous filters that are stacked to obtain different groups of average fiber diameters.

In addition, microfine fiber filaments having a fiber average diameter of 100 nm or less are manufactured by discharging a spinning solution under a high-voltage electric field and discharging it in a pulse form.

In one embodiment of the present invention, the function of adsorbing and removing viruses and heavy metal ions is imparted by adsorbing nano-alumina particles on the surface of the ultrafine fibers of the filter or by distributing the nano-alumina particles on the filter fiber layer.

Nano-alumina is boehmite (AlOOH), aluminum hydroxide (Al (OH) ₃₎ or gamma-and alumina _{(γ-Al 2 O 3)} , nano-alumina is the nano-rods, nano-tubes or nano-fibrous or these nano alumina each other And porous nano-particles formed by adsorbing nano-alumina on the surface of porous nanoparticles formed by agglomeration of porous nanoparticles or ceramic nanoparticles formed by agglomeration.

The introduction of the nano-alumina particles to the surface of the microfibers of the filter is carried out by introducing the nano-alumina dispersion solution into the microfibre filter layer, filtering the microfibers, and then introducing the nano-alumina particles into the microfibre filter layer.

In addition, in the electrospinning process for forming microfine fibers, nano alumina may be introduced into the microfine fiber layer by electrostatic spraying or air spraying of the nano-alumina dispersion solution using another nozzle.

In addition, it is also possible to produce ultrafine fibers having improved adsorption ability by further containing nano-alumina in the polymer solution, the ceramic precursor sol-gel solution or the mixed solution of the sol-gel solution and the polymer resin used in the production of the polymer filter of the invention have.

Nano-alumina can help trap very fine particles such as viruses, metal ions, organic matter, and inorganic particles.

Alternatively, the fibrous porous body may be impregnated with a suspension of nano-alumina, or the suspension may be coated on a porous body to produce a polymeric fibrous filter in which nano-alumina is adsorbed on the fiber surface.

The principle of electrospinning for forming ultrafine polymer fibers according to an embodiment of the present invention is well known in various documents. Electrostatic spray, which is a phenomenon in which a liquid having a low viscosity is sprayed into very fine droplets under a high- ), Microfibers are formed when a high-voltage electrostatic force is applied to a silica precursor, an alumina precursor or a sol-gel solution and a polymer mixture solution having a sufficient viscosity, which is called electrospinning. The electrospinning apparatus includes a barrel for storing a solution, a metering pump for discharging the solution at a constant rate, and a spinning nozzle connected to a high voltage generator. The solution discharged through the metering pump is discharged as ultrafine polymer fibers through the spinning nozzles charged by the high voltage generator, and the porous ultrafine polymer fibers are accumulated on a grounded collector plate of a conveyor type moving at a constant speed. Electrospinning of such a solution makes it possible to produce ultrafine polymer fibers having a size of several nanometers to several nanometers and fuse with a three-dimensional network structure at the same time as the generation of fibers, . The ultrafine polymeric fibrous porous body has an extremely high volume to surface area ratio and a high porosity as compared with conventional fibers.

In one embodiment of the present invention, the formation of the ultrafine polymeric fibrous phase is accomplished by melt-blowing, flash spinning, or a modification of these processes, extending the concept of electrospinning as described above, Can be carried out by an electro-blowing method for producing fibers. Since all of these methods have the same concept as the electrospinning method of extruding through a nozzle under an electric field, the electrospinning in one embodiment of the present invention includes all these methods.

The filtration accuracy of the filter, that is, the filtration efficiency and the permeation flow rate, is most affected by the porosity and pore size of the filtration layer. According to an embodiment of the present invention, the pore size, distribution and porosity of the ultrafine fibrous filter as the filtration layer are greatly affected by the average diameter and the diameter distribution of the constituent fibers. The smaller the fiber diameter, the smaller the pore size and the smaller the pore size distribution. Further, as the diameter of the fibers is smaller, the specific surface area of the fibers is increased, so that the ability to collect fine particles contained in the filtrate becomes larger.

In the case of a membrane filter, the surface pore size differs from the pore size and porosity inside the membrane. This is due to the difference in the evaporation or dissolution rate of the solvent on the membrane surface and in the membrane manufacturing process, and there is a dead end pore that does not contribute to the filtration. However, in the case of a filter made of fibers, the surface pore size and porosity do not show much difference from the filter bulk, and there is also no dead end pore. Porosity is not a direct factor in evaluating the performance of a filter, but a higher porosity means higher permeate flux. Therefore, in the filter of an embodiment of the present invention, the diameter of the constituent fibers is controlled by a method of controlling the pore size of the filtration layer capable of high filtration efficiency and high permeate flux.

In general, the fiber diameter of a conventional filament filter produced by electrospinning does not decrease proportionally with the pore size and the pore size as the fiber diameter becomes smaller. For example, when the mean fiber diameters are 2.3 μm, 1.3 μm, 0.7 μm, and 0.5 μm, the largest (largest frequency) pore size in the pore size distributions is 6.7 μm, 4.5 μm, 2.2 μm, and 1.7 μm, and the porosity decreases from 90% to 80%. That is, the porosity and the pore size do not decrease much as compared with the decrease in the fiber diameter. As in Comparative Example 1, when the average fiber diameter was changed to 186 nm and 100 nm, the water permeation flow rate and the particle filtration efficiency were greatly increased, but the water permeation flux was much higher than that, There is a need for a filter that removes particles that are finer than 200 nm particles of bacterial size with high filtration efficiency.

Particularly, it is very difficult to greatly reduce the pore size of the fibrous porous body produced by the conventional electrospinning in order to filter ultrafine particles smaller than bacteria at a high efficiency and a high permeation flow rate. In the case of producing such porous body having a small pore size High filtration efficiency can be obtained, but the permeate flow rate is significantly reduced due to the low permeation rate.

Therefore, in an embodiment of the present invention, the microfibre layer having an average fiber diameter of 1 to 50 nm (preferably 10 to 30 nm) is contained in the filtration layer of the microfine fiber filter, Efficiency. Ultrafine fibers having an average fiber diameter of 1 to 50 nm (preferably 10 to 30 nm) are uniformly distributed in the filter layer or alternately stacked with a fiber group having a larger diameter to obtain a high flow rate and a high filtration efficiency Ultrafine fibrous filter.

In order to filter ultrafine particles such as viruses with high efficiency, the pore size of the filtration layer should be about 1 to 100 nm, more preferably about 1 to 60 nm. However, the filtration layer having such microscopic holes has a very high filtration efficiency, but is problematic because of the pressure loss being too large and the permeation capacity being too low. Therefore, it is not desirable to filter out the leachate such as virus using only the pore size of the filtration layer.

The filtration efficiency of the leaner, such as viruses, may not be high with only the filtration layer of the embodiment of the present invention. Therefore, in order to have a high filtration efficiency and a high permeation flow rate for ultrafine particles such as virus, it is possible to use a larger pore size but to impart the function of adsorbing the filtration particles to the surface of the fiber. Namely, it is possible to remove viruses and heavy metals by adsorption by introducing nano alumina into the ultrafine fiber filtration layer.

Meanwhile, the filter having the ultrafine fibrous porous body, which is the filtration layer of one embodiment of the present invention, can be used in various forms including a laminated form in a flat state, a pleats type, and a spiral type. have.

Further, one embodiment of the present invention is a method of electrospinning a mixed solution of a polymer, a ceramic precursor, or a mixture of a sol-gel solution of a polymer and a polymer resin to form a microfine fiber group having an average fiber diameter of 100 nm or less Or a mixture of microfibers having an average fiber diameter of 100 nm or less and an ultrafine fiber group having a fiber average diameter of 100 nm or more so that the water permeation flow rate at 2.5 psi is at least 7,500 L / hr.m ² , An ultrafine fibrous filter having a filtration efficiency of 98% or more of 200 nm particles or a high permeation flow rate of 100 nm particles having a filtration efficiency of 98% or more while having a permeation flow rate of at least 1,000 L / hr.m ² or more, Of the present invention. The specific conditions in the above method are as described above.

Hereinafter, embodiments of the present invention will be described in detail with reference to the following examples. However, the following examples are only examples of the present invention, and the present invention is not limited to the following examples.

The fiber diameter, pore size and distribution, porosity, air permeability and water permeation flow rate, and filtration efficiency shown in Examples of the embodiment of the present invention were measured by the following methods.

1. The heat resistance of the filter Ultrafine Polymer fiber diameter

From the SEM photograph of the surface or cross section of the heat-resistant ultrafine polymeric fibrous porous article of one embodiment of the present invention, the diameter of the ultrafine polymer fibers was measured using Sigma Scan Pro 5.0 and SPSS, and the average diameter and fiber diameter distribution of the fibers were evaluated.

2. Heat resistance Ultrafine Polymeric fiber The pore size, distribution and air permeability of the porous article

The average pore size was measured in a pressure range of 0-30 psi using a capillary flow porometer (PMI, CFP-1500AE, version 7.0) and the pore size was measured by the measured wet flow and dry flow dry flow curve, and perfluoropolyether (propene 1,1,2,3,3,3 hexafluoro, oxidized, polymerized) was used as a wetting agent. The pore size distribution was determined by comparing wet flow and dry flow gas flow rates at the same pressure.

3 . Water permeation flow rate evaluation

To evaluate the water permeate flow rate, a dead-end AMICON stirred cell (8010) unit with a volume of 10 mL was used and a 2000 mL capacity water storage tank was connected to the unit. The effective filter area was 4.1 cm ² (diameter 20 mm), and the permeate permeated through the filter was measured in real time using a Labeller balance balance equipped with LabX direct balance software (Mettler-Toledo International Inc.) Lt; / RTI >

Water flow rate = Q / tA

Q: Water permeation volume (L) at time t, at 2.5 psi and 10 psi pressure,

t: hour (hr)

A: effective filter area

3. Evaluation of Filtration Accuracy (Filtration Efficiency)

A 100 ppm suspension of polystyrene latex particles (Magsphere Inc.) with diameters of 200 nm, 104 nm, 60 nm and 23 nm was dispersed in the same dead-end AMICON stirred cell (8010) unit as the water permeation flow- Was supplied for 20 minutes. The filtered solution was taken over time and an absorption spectrum between 190 and 400 nm was obtained using a UV spectrometer (Jasco Co. V-670). Since the absorption spectrum at 230 nm (220 nm at a particle diameter of 100 nm or less of latex particle size) is due to the polystyrene latex particles, the filtration efficiency was determined by the following equation using this.

Particle filtration efficiency (%) = [( A _ori - A _filt ) / ( A _ori - A _wate _r )

A _ori : UV absorbance of a 100 ppm polystyrene latex suspension aqueous solution at 230 nm

A _filt : The UV absorbance of the filtrate after filtration through the filter at 230 nm,

A _wate _r : UV absorbance at 230 nm of pure water

Comparative Example One: Monostable Ultrafine SiO ₂ / PVdF Compound fiber Filter Manufacturing

51.5 g of tetraethoxyorthosilicate (TEOS, Aldrich), 24.9 g of ethyl alcohol, 9.6 g of water and 0.28 g of an aqueous hydrochloric acid solution were mixed and stirred at about 70 ° C for about 3 hours to prepare 31 g of a silica sol-gel solution Respectively. To the solution was added 140 g of a DMF solution in which 14 g of polyvinylidene fluoride (PVdF, Kynar 761) had been dissolved to obtain a mixed solution. The mixed solution was then subjected to a high voltage electric field of 20 kV using an electrospinning device, Speed and a spinning nozzle of 30 G to fabricate a silica composite PVdF fibrous filter having a fiber average diameter of 186 nm and a thickness of about 110 탆 (Fig. 1 (a)). The silica composite PVdF fiber has a sea-island microfine fiber structure in which the silica component has a surface structure, the silica nanofiber as a component, and the PVdF as a sea component, as shown in a transmission electron microscope photograph in FIG. 1 (a). However, this fibrous porous material is a filter material produced by conventional electrospinning, which does not contain a microfine fiber group having an average fiber diameter of 100 nm or less (particularly, 10 to 30 nm) in the microfine fiber group (Table 1). The filtration efficiency was measured using the above porous body as a filter filtration layer at a pressure of 2.5 psi and a pressure of 10 psi, and the filtration efficiency of 200 nm polystyrene latex particles evaluated at a pressure of 5 psi is shown in Table 2.

Comparative Example 2 Monostable Ultrafine Polyvinyl alcohol Fibrous Filter Manufacturing

The solution prepared by dissolving 10% by weight of polyvinyl alcohol (PVA, degree of polymerization 1700, degree of saponification 86 to 91%) in water was discharged at about 10 μL / min under a high voltage electric field of 30 kV using a spinneret of 30 G To fabricate a PVA ultrafine fibrous filter having a fiber average diameter of 100 nm and a thickness of about 10 μm. The filter is a filter material produced by a conventional electrospinning method that does not contain a group of microfine fibers having an average fiber diameter of 10 to 30 nm (Fig. 1 (b) and Table 1). Using the porous material as a filter layer, And 2.5 psi and 10 psi permeability were measured. The filtration efficiencies of 200 nm and 104 nm polystyrene latex particles evaluated at a pressure of 5 psi are shown in Table 2. The filter almost filtered the 200 nm diameter particles and the water permeability was very good, but the filtration efficiency was very low for the 104 nm particles. The water permeability and particle filtration efficiency of the Millipore GSWP 0.22 μm membrane filter capable of bacterial size particle filtration and the nanosilam filter capable of virus adsorption removal were also compared

Comparative Example 1 Comparative Example 2 GSWP Nano ceramics Thickness (㎛) 110 10 176 1000 Average fiber diameter (nm) 186 100 - - Average rolling number
(Gurley Number) 1.79 4.22 11.69 5.63 Mean Flow Pore Diameter (㎛) 0.61 0.47 0.33 0.66 Maximum pore diameter (탆) 0.68 0.56 0.67 34.79 Pure permeate flow rate (L / m ² h)
10 psi 53250 27500 9538 26117 Pure permeate flow rate (L / m ² h)
2.5 psi 15920 7500 2729 6975 Particle filtration efficiency (%)
(Polystyrene standard particle size 200 nm) 85.42 98.12 95.90 39.20 Particle filtration efficiency (%)
(Polystyrene standard particle size 104 nm) - 19.23 - -

Example One: High flow rate PVdF / m- aramid Fibrous Filter Manufacturing

1-1. This dispersion (bimodal distribution ) PVdF / meta - aramid (= 8/2 ) composite microfiber fabric with fiber diameter distribution

A dimethylacetamide solution in which a mixture of 1.64% by weight of anhydrous calcium chloride (CaCl ₂ ) and 16% by weight of a mixture of polyvinylidene fluoride (PVdF) / meta-aramid (= 8/2 by weight) Respectively. Electrospinning was carried out at a temperature of 35 ° C, a relative humidity of 20%, a nozzle-collector distance of 11 cm, a high voltage of 26 kV, a 30 G needle and a polymer solution discharge flow rate of 1 μL / min. The fabricated ultrafine fibers are composed of PVdF as a conductive component and meta-aramid as a seawater, thereby forming a structure in which a large amount of meta-aramid is distributed on the surface of the fiber, and the filter obtained therefrom is shown in FIG. 2 (a). The fiber group with average fiber diameter of 126 nm and the fiber group with average fiber diameter of 22 nm are distributed, and this distribution of fiber diameter is clearly shown. The filtration efficiency and the pure permeation flow rate were measured using the porous body as a filter filtration layer, and the results are shown in Table 2.

1-2. This dispersion Fiber diameter distribution Have PVdF / Meta - Aramid (= 7/3) complex Ultrafine Textile Manufacturing

A dimethylacetamide solution in which a mixture of 4% by weight of anhydrous calcium chloride (CaCl ₂ ) and 16% by weight of a mixture of polyvinylidene fluoride (PVdF) / meta-aramid (= 7/3 by weight) Respectively. Electrospinning was carried out at a temperature of 17 ° C, a relative humidity of 11%, a nozzle-collector distance of 8 cm, a high voltage of 30 kV, a 30 G needle and a polymer solution discharge flow rate of 1 μL / min. The fabricated microfine fibers are shown in Fig. 2 (b). The fiber group with average fiber diameter of 93 nm and the fiber group with average fiber diameter of 17 nm are distributed, and the distribution of the dispersed fiber diameter is clearly shown. The filtration efficiency and the pure permeation flow rate were measured using the porous body as a filter filtration layer, and the results are shown in Table 2.

1-3 This dispersion Fiber diameter distribution Have PVdF / Meta - Aramid (= 6/4) composite Ultrafine Textile Manufacturing

A dimethylacetamide solution in which a mixture of 2.7 wt% of anhydrous calcium chloride (CaCl ₂ ) and 16 wt% of a mixture of polyvinylidene fluoride (PVdF) / meta-aramid (= 6/4 weight ratio) Respectively. Electrospinning was carried out at a temperature of 35 ° C, a relative humidity of 20%, a nozzle-collector distance of 11 cm, a high voltage of 21 kV, a 30 G needle and a polymer solution discharge rate of 1 μL / min. The fabricated microfine fiber is shown in Fig. 2 (c). The distribution of the diameter of the dispersed fibers is clearly shown by distributing the fiber group having the average fiber diameter of 134 nm and the fiber group having the average fiber diameter of 20 nm. The filtration efficiency and the pure permeation flow rate were measured using the porous body as a filter filtration layer, and the results are shown in Table 2.

Example 2: This dispersion Fiber diameter distribution Have Ultrafine PVdF / SiO ₂ (= 7/3) complex Fibrous Filter Manufacturing

62.4 g of TEOS, 29.8 g of ethyl alcohol, 9.6 g of water and 0.28 g of an aqueous hydrochloric acid solution were mixed and stirred at about 70 캜 for about 3 hours to prepare 30 g of a silica sol-gel solution. 13 g of DMF, 0.0283 g of calcium chloride and 4.9 g of PVdF were added to 17.4 g of the solution to obtain a mixed solution. Then, the mixed solution was applied to a high voltage electric field of 28 kV, a discharge rate of 1 L / min and a spinning nozzle Under the conditions of a nozzle-collector distance of 10 cm to prepare a silica composite polyacrylonitrile fibrous porous article. As shown in FIG. 3, the filter has a fiber diameter of 114 nm and a fiber diameter of 21 nm. The filtration efficiency and the pure permeation flow rate were measured using the porous body as a filter filtration layer, and the results are shown in Table 2.

Example 3: High flow rate Ultrafine PVdF Fibrous Filter Manufacturing

3-1. This dispersion Fiber diameter distribution Have Ultrafine PVdF Fibrous Filter Manufacturing

A 13% by weight PVdF solution prepared by dissolving 3.9 g of PVdF in 26.1 g of DMF dissolved in 0.1% by weight of salt was applied to a high-voltage electric field of 27 kV, an ejection speed of 10 μL / min and a spinning nozzle of 30 G And the mixture was subjected to electrospinning at a temperature of 41 ° C, a relative humidity of 16% and a nozzle-collector distance of 8.5 cm to prepare a filter having an average fiber diameter of 69.9 nm and a thickness of 14 μm. (Fig. 4 (a)). As shown in Fig. 4 (a), this filter shows that a small amount of microfibers having an average fiber diameter of 10 to 30 nm are distributed. The filtration efficiency and the pure permeation flow rate were measured using the porous body as a filter filtration layer, and the results are shown in Table 2.

3-2. This dispersion Fiber diameter distribution Have Ultrafine PVdF Fibrous Filter Manufacturing

4.8 g of PVdF and a 12 wt% PVdF solution prepared by dissolving 0.7 g of calcium chloride in 35.2 g of dimethylacetamide (DMAc) were irradiated with a high-voltage electric field of 25 kV, an ejection rate of 5 L / min and a spin speed of 30 G The electrode was electrospun using a nozzle at a temperature of 20 ° C, a relative humidity of 34% and a nozzle-collector distance of 15 cm to produce a microfibre filter (Fig. 4 (b)). As shown in FIG. 4 (b), the filter has a fiber diameter of 84 nm and a fiber diameter of 18 nm. The filtration efficiency and the pure permeation flow rate were measured using the porous body as a filter filtration layer, and the results are shown in Table 2.

The dispersed ultrafine fibrous filter of Examples 1 to 3 had a much higher net permeation flux than the GSWP filter of the comparative example and the commercial product, but the filtration efficiency of 200 nm and 104 nm particles was superior.

Example 4: By pulse supply Ultrafine Polymer Fibrous Filter Manufacturing

Using the same solution as in Example 3-2, a high-voltage electric field of 25 kV, a discharge rate of 0.5 μL / min and a spinning nozzle of 30 G were used to carry out electrical charging at a temperature of 20 ° C., a relative humidity of 29%, and a nozzle- Polymer solution was supplied in pulse form under the condition of supplying 60 seconds supply of polymer solution and 150 seconds supply of spinning solution while spinning. As shown in Fig. 5, the distribution of the dispersed fiber diameter is clearly shown

Example 5: This dispersion Fiber diameter distribution Have PAN Ultrafine Polymer Fibrous Filter Manufacturing

A 12 wt% PAN solution prepared by dissolving 3.6 g of polyacrylonitrile (PAN) and 0.528 g of calcium chloride in 26.4 g of dimethylacetamide (DMAc) was applied to a high voltage electric field of 26 kV using an electrospinning device, Speed and a spinning nozzle of 30G were electrospun under the conditions of a temperature of 22 DEG C, a relative humidity of 29% and a nozzle-collector distance of 15 cm to produce a microfibre filter (Fig. 6 (a)).

As shown in FIG. 6 (a), the filter has a fiber diameter of 152 nm and a fiber diameter of 23 nm. The filtration efficiency and the pure permeation flow rate were measured using the porous body as a filter filtration layer, and the results are shown in Table 2.

A 10 wt% PAN solution prepared by dissolving 4.5 g of polyacrylonitrile (PAN), 0.405 g of iron trichloride (FeCl ₃ ) or lithium chloride (LiCl) in 40.5 g of dimethylacetamide (DMAc) Using a high voltage electric field of 15 kV, a discharging speed of 5 μL / min and a spinning nozzle of 30 G, electrospun was performed under the conditions of a temperature of 42 ° C., a relative humidity of 18% and a nozzle-collector distance of 9 cm to obtain an ultrafine fibrous filter ) And 6 (c). All of these fibers are distributed in a group of microfine fibers having an average fiber diameter of 10 to 30 nm, which clearly shows the distribution of the diameter of the dispersed fibers.

Example
1-1 Example
1-2 Example
1-3 Example
2 Example
3-1 Example
3-2 Example
5 Thickness (㎛) 10 10 10 10 14 10 10 The average fiber diameter (nm) of the large diameter fiber group 126 93 134 114 69.9 84 152 Average Diameter (nm) of 10-30 nm Fiber Group 22 17 20 21 15 18 23 Average rolling number
(Gurley Number) 2.32 6.02 2.11 3.52 5.94 6.30 1.97 Mean Flow Pore Diameter (㎛) 0.41 0.25 0.52 0.35 0.27 0.24 0.50 Maximum pore diameter
(탆) 0.50 0.35 0.53 0.49 0.34 0.33 0.57 Pure permeation flow rate
(L / m ² h, 10 psi) 51243 37035 52547 47891 36233 35125 52341 Pure permeation flow rate
(L / m ² h, 2.5 psi) 15183 10256 15421 14762 9993 9820 15545 Particle filtration efficiency (%)
(Polystyrene standard particle size 200 nm) 99.49 99.89 99.36 99.62 99.90 99.91 99.01 Particle filtration efficiency (%)
(Polystyrene standard particle size 104 nm) 49.87 89.24 42.67 60.79 92.15 94.20 42.69

Example 6: This dispersion Fiber diameter distribution Have PES Ultrafine Polymer Fibrous Filter Manufacturing

A 20 wt% PES solution prepared by dissolving 6.75 g of polyethersulfone (PES) and 0.54 g of calcium chloride in 27 g of dimethylacetamide (DMAc) was applied to a high voltage electric field of 29 kV using a electrospinning device, a discharge of 0.5 μL / Speed ultrafine fibrous filter having an average fiber diameter of 49.5 nm was prepared by spinning at a temperature of 24 ° C, a relative humidity of 28% and a nozzle-collector distance of 15 cm using a spinning nozzle of 30 G (Fig. 7 (a) . As shown in Fig. 7 (a), this filter has a small amount of a microfine fiber group having an average fiber diameter of 16 nm. In addition, a 17 wt% PES solution was spun under the same conditions to prepare a microfibre filter having an average fiber diameter of 24.3 nm (Fig. 7 (b)).

The pure filtrate flow rate was measured using the porous body as a filter filtration layer and shown in Table 3.

Example
6-1 Example
6-2 Thickness (㎛) 10 10 The average fiber diameter (nm) of the large diameter fiber group 49.3 24.3 Average Diameter (nm) of 10-30 nm Fiber Group 16 - Average rolling number
(Gurley Number) 11.05 14.53 Mean Flow Pore Diameter (㎛) 0.07 0.06 Maximum pore diameter
(탆) 0.35 0.31 Pure permeation flow rate
(L / m ² h, 10 psi) 7550 6550 Pure permeation flow rate
(L / m ² h, 2.5 psi) 2550 1510 Particle filtration efficiency (%)
(Polystyrene standard particle size 104 nm) 100 100 Particle filtration efficiency (%)
(Polystyrene standard particle size 60 nm) 100 100

Example 7: This dispersion Fiber diameter distribution The m- aramid Ultrafine Polymer Fibrous Filter Manufacturing

A 14 wt% meta-aramid solution prepared by dissolving 5.25 g of meta-aramid in 30 g of dimethylacetamide (DMAc) in which 2.26 g of calcium chloride was dissolved was sprayed using an electrospinning device at a discharge rate of 10 μL / min and a spinning nozzle of 30 G The ultrafine fibrous filter of various thicknesses was fabricated by electrospinning at a temperature of 22 ° C, a relative humidity of 25%, and a nozzle-collector distance of 10 cm, while varying the intensity of a high voltage electric field of 12 to 25 kV. The characteristics of the fabricated filter, the pure permeation flow rate and the particle filtration efficiency are shown in Tables 4 and 5. As shown in the filter 8 (a) to (c), the ultrafine fibrous filter produced at a relatively low electric field had a very small amount of the ultrafine fiber group of 100 nm or less, but the ultrafine fiber group of 100 nm or less The filtration efficiency of 200 nm polystyrene particles was higher, while having a much higher net permeate flow rate. Filters 8 (d) to (e) are broadly distributed over a wide range of microfine fibers of 100 nm or less in all areas. These filters have a slightly reduced pure permeation flow rate, nm, 60 nm, and 23 nm, respectively.

Example
7-a-10 Example
7-b-10 Example
7-b-20 Example
7-b-30 Example
7-c-10 Example
7-c-20 Example
7-c-30 Thickness (㎛) 10 10 20 30 10 20 30 The average fiber diameter (nm) of the large diameter fiber group 150 121 121 123 103 102 101 Average Diameter (nm) of 10-30 nm Fiber Group - - - - - - - Average rolling number
(Gurley Number) 1.99 2.5 5.72 6.73 4.26 6.31 7.01 Mean Flow Pore Diameter (㎛) 0.57 0.48 0.38 0.30 0.43 0.34 0.21 Maximum pore diameter
(탆) 0.63 0.56 0.49 0.44 0.54 0.47 0.33 Pure permeation flow rate
(L / m ² h, 10 psi) 53144 48378 44661 35277 46677 42037 32331 Pure permeation flow rate
(L / m ² h, 2.5 psi) 15178 14134 11820 8632 13143 11243 7632 Particle filtration efficiency (%)
(Polystyrene standard particle size 200 nm) 99.06 99.19 99.79 100 99.21 100 100 Particle filtration efficiency (%)
(Polystyrene standard particle size 104 nm) 36.60 39.71 - - 63.61 - - Particle filtration efficiency (%)
(Polystyrene standard particle size 60 nm) - - - - - - - Particle filtration efficiency (%)
(Polystyrene standard particle size 23 nm) - - - - - - -

Example
7-d-10 Example
7-d-20 Example
7-d-40 Example
7-e-10 Example
7-e-13 Thickness (㎛) 10 20 40 10 13 The average fiber diameter (nm) of the large diameter fiber group 103 102 101 83.4 83.8 Average Diameter (nm) of 10-30 nm Fiber Group 19.2 16.7 16.8 22 17 Average rolling number
(Gurley Number) 4.71 7.48 15.84 6.2 10.05 Mean Flow Pore Diameter (㎛) 0.30 0.26 0.18 0.23 0.07 Maximum pore diameter
(탆) 0.38 0.35 0.30 0.35 0.37 Pure permeation flow rate
(L / m ² h, 10 psi) 42886 36832 20755 34628 7050 Pure permeation flow rate
(L / m ² h, 2.5 psi) 12499 9461 3945 9524 1550 Particle filtration efficiency (%)
(Polystyrene standard particle size 200 nm) 99.48 100 100 99.95 100 Particle filtration efficiency (%)
(Polystyrene standard particle size 104 nm) 67.94 - 99.38 95.40 100 Particle filtration efficiency (%)
(Polystyrene standard particle size 60 nm) - - 55.31 46.55 100 Particle filtration efficiency (%)
(Polystyrene standard particle size 23 nm) - - - - 34

Example 8: Zirconia / PVdF Ultrafine Polymer Fibrous Filter Manufacturing

A solution prepared by dissolving 13.63 g of zirconia sol-gel solution and 2 g of PVdF in 4.37 g of DMF was irradiated with a high-voltage electric field of 13.5 kV, a discharge rate of 10 μL / min and a spinneret of 30 G at a temperature of 25 Zirconia / PVdF (1: 1) ultrafine fibrous filter was prepared by electrospinning under the conditions of a temperature of 25 ° C., a relative humidity of 29% and a nozzle-collector distance of 8 cm. The zirconia composite PVdF fiber is a sea-island ultrafine fiber structure in which a zirconium oxide component forms a surface structure as shown in Fig. 9 (a), and Fig. 9 (b) shows a surface morphology by sintering the composite fiber at 700 & This shows that zirconium oxide particles are exposed on the surface.

Example 9: Hydrophilic Ultrafine PVdF Fibrous Filter Manufacturing

PVDF / polyacrylic acid (7/3) solution prepared by dissolving 2.73 g of PVdF and 1.17 g of polyacrylic acid in 26.1 g of DMF in which 0.1% by weight of salt had been dissolved was irradiated at 27 kV At a temperature of 41 ° C, a relative humidity of 16%, and a nozzle-collector distance of 8.5 cm using a high voltage electric field of 10 μL / minute and a spinning nozzle of 30 G. The average fiber diameter was 100 nm, 15 < / RTI > This filter also shows a small distribution of microfibers having an average fiber diameter of 10 to 30 nm. The filter was irradiated with an electron beam to crosslink the solution to increase the hydrophilicity. The filter showed a pure permeate flow of 9,389 L / m ² h at 2.5 psi pressure, while 200 nm particles were 100% filtered at 5 psi pressure.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims

A microfine fiber group having a fiber average diameter of 100 nm or less or a microfine fiber group having a fiber average diameter of 100 nm or less and a microfine fiber group having a fiber average diameter of 100 nm or more,
At a pressure of 2.5 psi, the water permeation flow rate is over 7,500 L / hr.m ² and the filtration efficiency of the 200 nm particle is 98% or more, or the water permeation flow rate is more than 1,000 L / hr.m ² at 2.5 psi pressure. Flow filter having a filtration efficiency of 100 nm particles of 98% or more.

The method of claim 1,
Wherein the ultrafine fiber group having an average fiber diameter of 100 nm or less has an average fiber diameter of 10-30 nm.

The method of claim 1,
Wherein the microfine fiber group has a fiber diameter of 100 nm or less and the microfine fiber group having a fiber average diameter of 100 nm or more are mixed or a layer made of microfine fiber having an average fiber diameter of 100 nm or less and fibers having an average fiber diameter of 100 nm or more An ultrafine fibrous filter in which microfibre layers are stacked at an intersection.

The method of claim 1,
The ultrafine fibers constituting the ultrafine fiber group are formed by electrospinning a mixture of a polymer solution, a sol-gel solution of a ceramic precursor, and a sol-gel solution of a polymer and a ceramic precursor.

5. The method of claim 4,
Wherein the ceramic precursor is represented by M (OR) x, MRx (OR) y, MXy or M (NO ₃ ) y wherein M is Si, Al, or Zr, R is a C ₁ -C ₁₀ alkyl group, X Is F, Cl, Br, or I, x is an integer from 1 to 4, and y is an integer from 1 to 4. The microfibre-

5. The method of claim 4,
The polymer may be selected from the group consisting of polyacrylonitrile and copolymers thereof, poly (vinylidene fluoride) and copolymers thereof, cellulose, polyvinylpyrrolidone, polyamideimide, polyetherimide, polyimide, Water-soluble polymers including polyamide, aromatic polyamide (para and meta-aramid), polyphenylene sulfone, polysulfone, polyether sulfone, polyether ether ketone, polyvinyl alcohol, polyacrylic acid, polyethylene oxide, or -SO ₃ H, COOH or a polymer having an ionic functional group and a copolymer thereof.

The method of claim 1,
The ultrafine fibers constituting the microfine fiber group may be a polymer solution in which a metal salt containing at least one of FeCl ₃ , CaCl ₂ , MgCl ₂ , NaCl, LiCl, LiNO ₃ , or Fe (NO ₃ ) ₃ is dissolved, a sol of a ceramic precursor - gel solution and electrospinning of a mixture of polymer and ceramic precursor sol-gel solution.

The method of claim 1,
Wherein the nanofiber alumina particles are adsorbed on the surface of the ultrafine fibers constituting the ultrafine fiber group or distributed in the filter fiber layer.

9. The method of claim 8,
The nano-alumina are boehmite (AlOOH), aluminum hydroxide (Al (OH) ₃₎ or gamma-and alumina _{(γ-Al 2 O 3)} , the nano alumina are nanorods, nanotubes, or is nanofiber shape, a plurality of A porous ultrafine fibrous filter having porous nano-particles formed by adsorbing nano-alumina on the surface of porous nanoparticles formed by agglomeration of nano-alumina or porous nanoparticles formed by aggregation of ceramic nanoparticles.

The method of claim 1,
Wherein the ultrafine fibers constituting the ultrafine fiber group are formed from a mixed solution of a polymer having incompatibility with each other, and the hydrophilic polymer component is a sea component and the hydrophobic polymer component is a catalyst component.

The method of claim 1,
Wherein the ultrafine fibers constituting the ultrafine fiber group are ultrafine fibrous filters in which the ultrafine fibers mixed with the hydrophilic polymer are crosslinked by electron beam crosslinking or chemically crosslinked.

A polymer solution, a sol-gel solution of a ceramic precursor, and a mixed solution of a polymer and a sol-gel solution of a ceramic precursor are prepared, and
And a step of electrospinning the mixed solution to prepare a microfibre filter,
Wherein the ultrafine fibrous filter comprises:
A microfine fiber group having a fiber average diameter of 100 nm or less or a microfine fiber group having a fiber average diameter of 100 nm or less and a microfine fiber group having a fiber average diameter of 100 nm or more,
At a pressure of 2.5 psi, the water permeation flow rate is over 7,500 L / hr.m ² and the filtration efficiency of the 200 nm particle is 98% or more, or the water permeation flow rate is more than 1,000 L / hr.m ² at 2.5 psi pressure. Wherein the filtration efficiency of the 100 nm particle is 98% or more.

The method of claim 12,
The first microfine fiber group and the second microfine fiber group in which the fiber average diameter is different are different from each other by giving different discharging speeds of the spinning solution and different intensities of the applied high voltage, Gt;

The method of claim 12,
Wherein the ultrafine fiber group having a fiber average diameter of 100 nm or less is discharged in a pulsed form under high voltage.

The method of claim 12,
A method of manufacturing a microfibre filter for introducing nano-alumina into the ultrafine fibers constituting the microfine fiber group by injecting a nanosized alumina dispersion solution into the upper surface of the ultrafine fibrous filter, filtering the ultrafine fibrous filter, .

The method of claim 12,
Wherein the nano-alumina dispersion solution is electrostatically sprayed or air-sprayed using an independent nozzle in the step of electrospinning to introduce nano-alumina into the ultrafine fibers constituting the ultrafine fiber group.