Novel electrostatic spinning nanofiber membrane wrapped filter element

Abstract

The invention discloses a novel electrostatic spinning nanofiber membrane wrapped filter element, and relates to the technical field of filter elements, the novel electrostatic spinning nanofiber membrane wrapped filter element comprises a composite filter membrane, the composite filter membrane comprises a layer of nanofiber membrane and at least one layer of substrate non-woven fabric, the nanofiber membrane is woven on the substrate non-woven fabric through an electrostatic spinning technology, and the composite filter membrane is tightly rolled into a cylinder shape. The filter membrane comprises a non-woven fabric substrate on the bottom layer and a nanofiber membrane prepared through electrostatic spinning on the upper layer, a multi-layer barrel-shaped structure is formed in a roll type winding mode, a nanofiber membrane-base material-nanofiber membrane-base material composite structure is constructed, the two sides of nanofibers are tightly attached to the base material, effective protection supporting force is formed, and therefore the filter membrane can be effectively protected. Therefore, the mechanical property and the filtering efficiency of the filter membrane are remarkably improved, the service life of the filter membrane is prolonged, meanwhile, the dual functions of bacterium blocking and water permeation are achieved, the water treatment effect is optimized through the innovative design, and a new thought is provided for the water treatment technology in the future.

Description

Technical Field

[0001] The present invention relates to the technical field of filter elements, and particularly to a novel filter element wrapped with an electrospun nanofiber membrane. Background Art

[0002] With the acceleration of industrialization and urbanization, the problem of water resource pollution has become increasingly severe, which not only threatens the human living environment but also poses challenges to global sustainable development. Therefore, developing efficient and environmentally friendly water treatment technologies to purify sewage and protect water sources has become an urgent global task. In this context, nanofiber filtration technology stands out with its unique advantages. The diameter of nanofibers is only at the nanometer level, and the pore structure formed by the stacking of fibers is extremely tiny, which enables nanofiber membranes to exhibit excellent performance in gas and liquid filtration.

[0003] Electrospinning technology is an advanced manufacturing process that uses the electrostatic field force to stretch fluid jets to form ultrafine fibers. This technology can produce fibers with diameters ranging from dozens of nanometers to dozens of micrometers, featuring a high specific surface area, high porosity, and uniform fiber fineness. Moreover, the electrospinning preparation process is simple, easy to control, and has high production efficiency, making it particularly suitable for the batch preparation of nanofibers. However, there are some technical problems with the nanofiber membranes prepared by electrospinning. The mechanical strength of the nanofibers themselves is insufficient, and the binding ability with the substrate is poor. These problems will cause the membrane layer to be easily damaged and peeled off during the actual use of water treatment, thus affecting the filtration effect. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems raised in the above background art, and then a novel filter element wrapped with an electrospun nanofiber membrane is proposed. The filter membrane disclosed in the present invention includes a non-woven fabric substrate at the bottom layer and a nanofiber membrane prepared by electrospinning at the upper layer. A multi-layer barrel structure is formed by means of roll winding to construct a composite structure of nanofiber membrane - substrate - nanofiber membrane - substrate. The two sides of the nanofiber are closely attached to the substrate, forming an effective protective support force, thereby significantly improving the mechanical properties and filtration efficiency of the filter membrane, increasing the service life of the filter membrane, and simultaneously realizing the dual functions of bacteria resistance and water permeability. This innovative design not only optimizes the water treatment effect but also provides new ideas for future water treatment technologies.

[0005] The technical solution adopted by the present invention to solve its technical problems is: A novel filter element wrapped with an electrospun nanofiber membrane, comprising a multi-layer wound composite filter membrane. The composite filter membrane includes a layer of nanofiber membrane and at least one layer of base non-woven fabric. The nanofiber membrane is woven on the base non-woven fabric through electrospinning technology. The layers of the composite filter membrane are tightly combined and in a roll shape.

[0006] Preferably, the composite filter membrane of the filter element is wound in 2-100 layers, the inner diameter of the filter element is 1-10 cm, the outer diameter is 1-15 cm, and the composite filter membrane has micro-nano pores.

[0007] Preferably, the thickness of the nanofiber membrane is 1 um-100 um, and the diameter of the nanofibers is 50 nm-300 nm.

[0008] Preferably, the thickness of the base non-woven fabric is 1 um-100 um, and the diameter of the internal fibers is 1 um-100 um.

[0009] Preferably, the base non-woven fabric is made of PLA, and its grammage is 5-40 g / m 2 。

[0010] Preferably, the nanofiber membrane is prepared from at least one of PU polyurethane, PA nylon, PLA polylactic acid, and PEG polyethylene glycol.

[0011] Preferably, the basic parameters of the electrospinning technology are: temperature 25°C, humidity 50%, spinning distance 10~30 cm, voltage 70 Kv, current 20 mA, and spinning for 5-100 min.

[0012] Preferably, the composite filter membranes of the filter element are tightly bonded between each layer, and the water permeability ranges from 500-10000 L / (m 2 ·h), and can filter out 99.9% of colloids, bacteria, viruses, and suspended solids in water. It can be used in a relatively wide pH range and can be used under strong acids, strong alkalis, and different organic solution factors.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. The filter membrane disclosed in the present invention includes a non-woven fabric base layer at the bottom and a nanofiber membrane prepared by electrospinning on the upper layer. A multi-layer barrel structure is formed by a roll winding method, constructing a composite structure of nanofiber membrane - substrate - nanofiber membrane - substrate. The two sides of the nanofibers are closely attached to the substrate, forming an effective protective support force, thereby significantly improving the mechanical properties and filtration efficiency of the filter membrane, increasing the service life of the filter membrane, and simultaneously realizing the dual functions of bacteria resistance and water permeability. This innovative design not only optimizes the water treatment effect but also provides new ideas for future water treatment technologies.

[0014] 2. The winding number of the filter element disclosed in the present invention can be set according to the installation space of the filter element and the working requirements of the filter element, increasing the application range of the filter element.

[0015] 3. The nanofiber membrane obtained by the electrospinning technology disclosed in the present invention has a large number of pores and fine pore channels, which not only ensures the high efficiency of filtration but also prevents fine particulate matters, bacteria, etc. from passing through, enhancing the purification function of the filter element.

[0016] 4. The present invention has a strong bonding ability between the nanofiber membrane and the substrate, can withstand a large transmembrane pressure, has good air permeability, obtains a healthy and pure water source, and plays a very strong promoting role in the development of water purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the filter element disclosed in the present invention; Figure 2 is a schematic cross-sectional structural diagram of the filter membrane disclosed in the present invention; Figure 3 is a schematic diagram of the water purification principle of the filter element disclosed in the present invention; Figure 4 is a SEM image of the nanofibers inside the filter element disclosed in the present invention.

[0018] Among them: 1. Base non-woven fabric; 2. Nanofiber membrane. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0020] Example 1, as Figures 1 - 4 shown, a novel electrospun nanofiber membrane-wrapped filter element includes a multi-layer wound composite filter membrane. The composite filter membrane includes a layer of nanofiber membrane 2 and at least one layer of base non-woven fabric 1. The nanofiber membrane 2 is woven on the base non-woven fabric 1 by electrospinning technology. The composite filter membrane layers are tightly combined and in a roll shape.

[0021] The composite filter membrane of the filter element is wound 2 - 100 layers. The inner diameter of the filter element is 1 - 10 cm, and its outer diameter is 1 - 15 cm. The composite filter membrane has micro-nano pore channels.

[0022] It should be noted that, as Figure 1 shown, the winding layer number of the composite filter membrane is selected according to the installation space of the filter element and the working requirements of the filter element. The internal filtration structure of the filter element forms a composite structure of nanofiber membrane - substrate - nanofiber membrane - substrate. The nanofiber membrane provides the water purification function, and the substrate plays a supporting role, improving the mechanical strength of the filter membrane, protecting the nanofiber membrane at the same time, avoiding the nanofiber membrane from being deformed too much and damaged by the water flow pressure, and improving the service life of the membrane.

[0023] The thickness of the nanofiber membrane is 1um-100um, and the diameter of the nanofiber is 50nm-300nm.

[0024] The thickness of the base nonwoven fabric is 1um-100um, and the internal fiber diameter is 1um-100um.

[0025] The base nonwoven fabric is made of PLA and has a gram weight of 5-40 g / m 2 .

[0026] The nanofiber membrane is prepared by using at least one of PU polyurethane, PA nylon, PLA polylactic acid and PEG polyethylene glycol.

[0027] like Figure 2 As shown, it is a schematic diagram of the cross-sectional structure of the filter membrane disclosed in the present invention, in which a nanofiber membrane is woven on the surface of a base non-woven fabric by electrospinning, and the basic parameters of the electrospinning technology are: temperature 25°C, humidity 50%, spinning distance 10-30cm, voltage 70Kv, current 20mA and spinning 5-100min.

[0028] It should be noted that the existing electrospinning technology cannot prepare nanofiber membranes that meet the requirements. After experimental research, the basic parameters of the electrospinning technology are adjusted to meet the requirements for making high-performance filter elements. In the electrospinning process, the spinning distance will vary depending on the type of polymer used and the properties of the spinning solution. The essence of the entire spinning process is that during the injection process of the polymer jet, as the solvent continues to evaporate, the solute gradually changes from liquid to solid, and finally forms fibers. The degree of solution volatilization is closely related to the spinning distance. When the spinning distance is short, the time taken for the spinning solution jet to reach the substrate is correspondingly reduced, and the amount of solvent volatilization is also reduced; on the contrary, if the spinning distance is long, the jet stays in the air for a longer time, and the degree of solution volatilization will increase. The basic principle followed by the present invention in determining the spinning distance is to ensure that the polymer jet is in a semi-solid state at the moment it falls on the surface of the substrate, that is, the fiber has not yet been fully solidified. In this way, partial cross-linking can be achieved between the fibers that are not fully solidified. This cross-linking effect can significantly improve the mechanical properties of the membrane, making it have higher strength and toughness to meet the strength requirements of the water treatment membrane.

[0029] The composite filter membrane of the filter element is tightly combined with each other, and its water permeability ranges from 500-10000L / (m 2 h), can filter out 99.9% of colloids, bacteria, viruses and suspended solids in water. It can be used in a relatively wide pH range and can be used in strong acids, strong bases and different organic solution factors.

[0030] like Figure 3As shown in the figure, this is the schematic diagram of the filter element for purifying water in the present invention. The liquid with mixed impurities is purified by the filter element. Using the water purification pressure difference, the purified water passes through the pores of the nanofiber membrane. After selective filtration, the pure and healthy water flows out from the pores, and the impurities inside are isolated and discharged by the filter membrane, completing the purification of the liquid.

[0031] An experimental study was conducted on an embodiment of the filter element. The thickness of the electrospun membrane is 60 μm, and the diameter of the nanofibers is 70 nm; the substrate is non-woven fabric, the thickness of the non-woven fabric is 150 μm, and the fiber diameter of the non-woven fabric is 5 μm. Then, the filter membrane is wound 35 layers by equipment to ensure its high mechanical properties and bonding ability. As Figure 4 shown by SEM observation and calculation, there are about 50,000 nanofiber membrane channels per square millimeter (after obtaining the specific pore size distribution and channel number using SEM images, the average pore size and distribution are measured by using image analysis software to statistically analyze multiple pore sizes). The well-bonded filter element has very dense nanofiber channels, which can allow small molecule water and minerals to pass through, obtaining a healthy and clean water source. The above filter element was tested through experiments. The water flow rate that the filter element can handle is 637 (m 2 / h). By detecting the purified water after filtration, it is determined that the filter element can remove 99.23% of harmful substances such as colloids, bacteria, and suspended solids in the water. The removal rate of yellow clay is above 95%, and the removal rates of elements such as lead and cadmium reach 98.88% and 99.18% and above.

[0032] It can be determined that the filter element disclosed in the present invention has excellent filtration performance and good mechanical strength, improving the service life of the filter element; at the same time, the number of filter membrane turns, the thickness of the electrospun membrane and the fiber diameter, as well as the thickness and fiber diameter of the non-woven fabric can be set according to the filter element installation space and the working requirements of the filter element.

[0033] Embodiment 2: A novel filter element wrapped with an electrospun nanofiber membrane, including a multi-layer wound composite filter membrane. The composite filter membrane includes a layer of base non-woven fabric 1, a layer of nanofiber membrane 2, and a layer of base non-woven fabric 1 arranged in sequence. The nanofiber membrane 2 is woven on the base non-woven fabric 1 through electrospinning technology, and the other layer covers the other side of the nanofiber membrane 2. The composite filter membrane layers are tightly combined and in a roll shape.

[0034] The composite filter membrane of the filter element is wound 2 - 100 layers. The inner diameter of the filter element is 1 - 10 cm, and its outer diameter is 1 - 15 cm. The composite filter membrane has micro-nano pores.

[0035] The thickness of the nanofiber membrane is 1 μm - 100 μm, and the diameter of the nanofibers is 50 nm - 300 nm.

[0036] The thickness of the base non-woven fabric is 1um - 100um, and the diameter of the internal fibers is 1um - 100um.

[0037] The base non-woven fabric is made of PLA, and its grammage is 5 - 40g / m 2 .

[0038] The nanofiber membrane is prepared from at least one of PU polyurethane, PA nylon, PLA polylactic acid, and PEG polyethylene glycol.

[0039] As Figure 2 shown, it is a schematic cross-sectional structure diagram of the filter membrane disclosed in the present invention. The nanofiber membrane is spun on the surface of the base non-woven fabric by electrospinning. The basic parameters of the electrospinning technology are: temperature 25°C, humidity 50%, spinning distance 10 - 30cm, voltage 70Kv, current 20mA, and spinning time 5 - 100min.

[0040] Each layer of the filter element is tightly combined, and its water permeability range is 500 - 10000L / (m 2 ·h), and it can filter out 99.9% of colloids, bacteria, viruses, and suspended solids in water.

[0041] The filter membrane described in this embodiment improves the mechanical strength. Under the same filter element size, the mechanical strength and water permeability of the filter element described in Embodiment 2 are higher than those of the filter element described in Embodiment 1. The filtering effect and production cost of the filter element described in Embodiment 2 are lower than those of the filter element described in Embodiment 1. When the installation space of the filter element is relatively large, the filter membrane described in Embodiment 2 can be selected to prepare the filter element, which not only ensures the filtering effect of the filter element but also has a relatively low production cost. At the same time, due to the relatively large amount of non-woven fabric base, the mechanical strength of the filter element is greatly enhanced, thereby extending the service life of the filter element.

[0042] In the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "vertical", "horizontal", etc. is based on the orientation or positional relationship shown in the drawings, and is only for describing the present invention rather than requiring the present invention to be constructed or operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. The terms "connected" and "coupled" in the present invention should be understood in a broad sense. For example, it can be a connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0043] The above is the preferred operation mode of the present invention. The description of the specific operation mode is only for better understanding the idea of the present invention. For those of ordinary skill in the art, several improvements or equivalent replacements can be made according to the principle of the present invention, and these improvements or equivalent replacements are also regarded as falling within the protection scope of the present invention.

Claims

1. A novel electrostatic spinning nanofiber membrane-wrapped filter element, comprising a multi-layer wound composite filter membrane, characterized in that: The composite filter membrane includes a layer of nanofiber membrane and at least one layer of base non-woven fabric. The nanofiber membrane is spun onto the base non-woven fabric through electrospinning technology. The composite filter membrane is tightly bonded between layers and is in a roll shape.

2. A novel electrospun nanofiber membrane-wrapped filter element according to claim 1, characterized in that: The composite filter membrane of the filter element is wound in 2 - 100 layers. The inner diameter of the filter element is 1 - 10 cm, and its outer diameter is 1 - 15 cm. The composite filter membrane has micro-nano pore channels.

3. A novel electrospun nanofiber membrane-wrapped filter element according to claim 1, characterized in that: The thickness of the nanofiber membrane is 1 um - 100 um, and the diameter of the nanofibers is 50 nm - 300 nm.

4. A novel electrospun nanofiber membrane-wrapped filter element according to claim 1, characterized in that: The thickness of the base non-woven fabric is 1 um - 100 um, and the diameter of the internal fibers is 1 um - 100 um.

5. A novel electrospun nanofiber membrane-wrapped filter element according to claim 1, characterized in that: The base non-woven fabric is prepared from PLA, and its grammage is 5-40 g / m 2 .

6. A novel electrospun nanofiber membrane-wrapped filter element according to claim 1, characterized in that: The nanofiber membrane is prepared from at least one of PU polyurethane, PA nylon, PLA polylactic acid, and PEG polyethylene glycol.

7. A novel electrospun nanofiber membrane-wrapped filter element according to claim 6, characterized in that: The basic parameters of the electrospinning technology are: temperature 25°C, humidity 50%, spinning distance 10 - 30 cm, voltage 70 Kv, current 20 mA, and spinning time 5 - 100 min.

8. A novel electrostatic spinning nanofiber membrane-wrapped filter element according to claim 6, characterized in that: The composite filter membranes of the filter element are tightly bonded between each layer, and the water permeability range thereof is 500 - 10,000 L / (m 2 ·h).

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