A novel solvent-resistant nanofiltration membrane

Abstract

The utility model provides a novel solvent resistant nanofiltration membrane, including membrane shell, membrane group and water inlet end cover, membrane shell includes hollow cylindrical shell, and the lower extreme of cylindrical shell is integrally formed with water outlet end cover, and the lower extreme of water outlet end cover is equipped with the concentrated water export, is equipped with the circular convexity on the lateral wall of water outlet end cover, is equipped with the circular recess in circular convexity, is equipped with the cleaning pipe import that corresponds with circular recess on water outlet end cover, and the sealing cover is connected with cleaning pipe import threadedly, and the water inlet end cover includes the end cover shell body of section is U type structure, the through liquid discharge pipe that is integrally coaxial and is set through end cover shell body, the buffer net that is fixedly set in the inside of end cover shell body and the raw material import that is located buffer net top, the outer wall of cylindrical shell upper extreme is equipped with annular recess, and the lower extreme of end cover shell body is located in annular recess, and is equipped with the elastic rubber ring between end cover shell body and annular recess, the utility model has reduced the impact force to membrane element, can regularly clean concentrated water export, prolongs the life of membrane and so on advantage.

Description

Technical Field

[0001] This utility model belongs to the field of filtration membrane technology, and in particular relates to a novel solvent-resistant nanofiltration membrane. Background Technology

[0002] Nanofiltration membranes are a separation membrane technology between ultrafiltration and reverse osmosis. They are mainly used to remove various dissolved substances and particles from water. With the development of technology, in order to overcome the limitations of traditional nanofiltration membranes in terms of tolerance to extreme solvents such as strong acids and strong alkalis, solvent-resistant nanofiltration membranes have been developed to overcome the above limitations. Solvent-resistant nanofiltration can be used for the efficient separation of small organic molecules with molecular weights of 200-1000 in organic solvents.

[0003] Currently, when solvent-resistant nanofiltration membrane modules are started up, excessive influent flow rate and pressure can cause excessive impact on the membrane elements, which can easily damage them. In addition, the high solvent concentration at the concentrate outlet can easily lead to fouling after long-term operation, affecting the membrane filtration effect and service life. Summary of the Invention

[0004] The problem this invention aims to solve is to provide a novel solvent-resistant nanofiltration membrane that provides inlet water buffering, reduces the impact on membrane elements, allows for periodic cleaning of the concentrate outlet, extends membrane lifespan, and facilitates membrane element replacement.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a novel solvent-resistant nanofiltration membrane, comprising a membrane shell, a membrane assembly fixedly disposed inside the membrane shell, and an inlet end cap fixedly connected to the membrane shell. The membrane shell comprises a hollow cylindrical shell with an opening at the upper end and an outlet end cap integrally formed at the lower end. A concentrate outlet is provided at the lower end of the outlet end cap. A circular protrusion is provided on the side wall of the outlet end cap, and a circular groove is provided inside the circular protrusion. A cleaning pipe inlet corresponding to the circular groove is provided on the outlet end cap, and the circular groove and the cleaning pipe inlet are detachably installed. The device has a multi-hole water spray pipe, and the inlet of the cleaning pipe is threadedly connected to a sealing cap. The water inlet end cap includes an end cap shell with a U-shaped cross-section, a permeate outlet pipe integrally and coaxially disposed through the end cap shell, a buffer net fixedly disposed inside the end cap shell, and a raw material inlet located above the buffer net. One end of the permeate outlet pipe located inside the end cap shell passes through the buffer net and is fixedly connected to the membrane assembly. The inner wall diameter at the opening of the end cap shell is equal to the outer wall diameter of the cylindrical shell. An annular groove is provided on the upper outer wall of the cylindrical shell, and the lower end of the end cap shell is located in the annular groove. An elastic rubber ring is provided between the end cap shell and the annular groove.

[0006] Furthermore, the membrane module includes a central tube, a water collection hole disposed on the central tube, a nanofiltration membrane element fixedly wound on the central tube, and a first water distribution plate and a second water distribution plate fixedly disposed at both ends of the nanofiltration membrane element. One end of the central tube is a sealed end, which is sealed and inserted into the first water distribution plate. The other end of the central tube is an open end, which penetrates the second water distribution plate. An external thread is provided on the outer wall of the open end located outside the second water distribution plate.

[0007] Furthermore, an annular boss is fixedly provided on the lower inner wall of the cylindrical shell, the first water distribution plate is located on the annular boss, and an internal thread matching the external thread is provided on the lower inner wall of the permeate outlet pipe. The membrane module is fixedly installed in the cylindrical shell through the annular boss and the permeate outlet pipe.

[0008] Furthermore, both the first and second water distribution plates include a water distribution plate shell, a hollow connecting pipe located inside the water distribution plate shell and coaxially arranged, and a curved partition plate fixedly arranged between the water distribution plate shell and the hollow connecting pipe. The cross-section of the hollow connecting pipe is trapezoidal.

[0009] Furthermore, two first sealing grooves are provided on the outer wall of the water distribution plate shell, and a first sealing ring is provided in the first sealing groove for sealing between the water distribution plate shell and the cylindrical shell. Two second sealing grooves are provided on the inner wall of the hollow connecting pipe, and a second sealing ring is provided in the second sealing groove for sealing between the hollow connecting pipe and the central pipe.

[0010] Furthermore, the nanofiltration membrane element is formed by repeatedly stacking an inlet water guide net, a folded solvent-resistant nanofiltration membrane, and a product water guide net. The folded solvent-resistant nanofiltration membrane includes an upper membrane sheet and a lower membrane sheet, with a crease between the upper and lower membrane sheets. The inlet water guide net is located between the upper and lower membrane sheets, and the product water guide net is located on the upper membrane sheet. Each of the three free edges of the upper membrane sheet is provided with an adhesive strip, which is used to bond with the lower membrane sheet of the adjacent solvent-resistant nanofiltration membrane to form a membrane bag. The crease is fixedly connected to the central tube.

[0011] Furthermore, the nanofiltration membrane element also includes an adhesive tape sleeve for sealing and protecting the solvent-resistant nanofiltration membrane.

[0012] Furthermore, the buffer mesh is provided with a through hole for the liquid outlet pipe to pass through, several buffer holes for water flow buffering, and mounting holes for fixing to the water inlet end cover. The side wall of the water inlet end cover is provided with a mounting block, and the mounting block is provided with threaded holes corresponding to the mounting holes. The buffer mesh is fixed inside the water inlet end cover by bolts through the mounting holes and threaded holes.

[0013] Furthermore, a third sealing groove is provided on the outer wall of the cylindrical shell located above the annular groove, and a third sealing ring is provided in the third sealing groove for sealing between the cylindrical shell and the water inlet end cap.

[0014] Compared with the prior art, the advantages and beneficial effects of this utility model are: 1. The solvent-resistant nanofiltration membrane of this utility model can effectively buffer the inlet water pressure and flow by setting a buffer screen inside the inlet end cap. At the same time, combined with the water distribution plate structure, the inlet water pressure is further dispersed, reducing the impact on the membrane element, effectively protecting the membrane element and extending its service life. 2. The solvent-resistant nanofiltration membrane of this utility model is provided with a cleaning pipe inlet at the outlet end cap, combined with a circular groove. When dirt grows at the concentrate outlet and affects the membrane filtration effect, the sealing cover can be opened, and a multi-hole spray pipe can be fixed between the circular groove and the cleaning pipe inlet. The multi-hole spray pipe can be connected to the water supply system to regularly flush the concentrate outlet distribution plate, membrane and outlet end cap, thereby improving the service life of the membrane element. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of a solvent-resistant nanofiltration membrane according to this utility model.

[0016] Figure 2 This is a schematic diagram of the separate structure of the inlet cap and membrane shell of a solvent-resistant nanofiltration membrane according to this utility model.

[0017] Figure 3 This is a schematic diagram of the structure of a solvent-resistant nanofiltration membrane in the concentrate outlet cleaning state according to the present invention.

[0018] Figure 4 This is a schematic diagram of the structure of the first and second water distribution plates of a solvent-resistant nanofiltration membrane according to this utility model.

[0019] Figure 5 This is a schematic diagram of the structure of a solvent-resistant nanofiltration membrane element according to the present invention.

[0020] Figure 6 This is a schematic diagram of the buffer mesh structure of a solvent-resistant nanofiltration membrane according to this utility model.

[0021] In the diagram: 1-Membrane housing; 2-Membrane module; 3-Inlet cap; 4-Cylindrical housing; 5-Opening; 6-Outlet cap; 7-Concentrate outlet; 8-Circular protrusion; 9-Circular groove; 10-Cleaning pipe inlet; 11-Perforated spray pipe; 12-Sealing cap; 13-End cap housing; 14-Permeate outlet pipe; 15-Buffer screen; 16-Raw material inlet; 17-Annular groove; 18-Elastic rubber ring; 19-Center tube; 20-Water collection hole; 21-Nanofiltration membrane element; 22-First water distribution plate; 23-Second water distribution plate; 24-Sealed end; 25-Opening end; 26-Outer Thread; 27-Annular boss; 28-Internal thread; 29-Water distribution plate shell; 30-Hollow connecting pipe; 31-Curved partition; 32-First sealing groove; 33-First sealing ring; 34-Second sealing groove; 35-Second sealing ring; 36-Inlet water guide net; 37-Solvent-resistant nanofiltration membrane; 38-Product water guide net; 39-Upper membrane; 40-Lower membrane; 41-Fold; 42-Adhesive strip; 43-Tape sleeve; 44-Through hole; 45-Buffer hole; 46-Mounting hole; 47-Mounting block; 48-Third sealing groove; 49-Third sealing ring. Detailed Implementation

[0022] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0023] like Figures 1-6 As shown, a novel solvent-resistant nanofiltration membrane includes a membrane housing 1, a membrane assembly 2 fixedly disposed inside the membrane housing 1, and an inlet cap 3 fixedly connected to the membrane housing 1. The membrane housing 1 includes a hollow cylindrical shell 4, with an opening 5 at the upper end of the cylindrical shell 4. An outlet cap 6 is integrally formed at the lower end of the cylindrical shell 4, with a concentrate outlet 7 at the lower end of the outlet cap 6. A circular protrusion 8 is provided on the side wall of the outlet cap 6, and a circular groove 9 is provided inside the circular protrusion 8. A cleaning pipe inlet 10 corresponding to the circular groove 9 is provided on the outlet cap 6. A multi-hole spray pipe 11 is detachably installed between the circular groove 9 and the cleaning pipe inlet 10. The cleaning pipe inlet 10 is threadedly connected to a tight-fitting... The cap 12 and the water inlet cap 3 include a cap shell 13 with a U-shaped cross-section, a permeate outlet pipe 14 integrally and coaxially disposed through the cap shell 13, a buffer net 15 fixedly disposed inside the cap shell 13, and a raw material inlet 16 located above the buffer net 15. One end of the permeate outlet pipe 14 located inside the cap shell 13 passes through the buffer net 15 and is fixedly connected to the membrane assembly 2. The inner wall diameter at the opening of the cap shell 13 is equal to the outer wall diameter of the cylindrical shell 4. An annular groove 17 is provided on the upper outer wall of the cylindrical shell 4. The lower end of the cap shell 13 is located in the annular groove 17. An elastic rubber ring 18 is provided between the cap shell 13 and the annular groove 17.

[0024] Furthermore, the membrane module 2 includes a central tube 19, a water collection hole 20 disposed on the central tube 19, a nanofiltration membrane element 21 fixedly wound on the central tube 19, and a first water distribution plate 22 and a second water distribution plate 23 fixedly disposed at both ends of the nanofiltration membrane element 21. One end of the central tube 19 is a sealed end 24, which is sealed and inserted into the first water distribution plate 22. The other end of the central tube 19 is an open end 25, which penetrates the second water distribution plate 23. An external thread 26 is provided on the outer wall of the open end 25 located outside the second water distribution plate 23.

[0025] Furthermore, an annular boss 27 is fixedly provided on the lower inner wall of the cylindrical housing 4, the first water distribution plate 22 is located on the annular boss 27, and an internal thread 28 matching the external thread 26 is provided on the lower inner wall of the permeate outlet pipe 14. The membrane module 2 is fixedly installed in the cylindrical housing 4 through the annular boss 27 and the permeate outlet pipe 14.

[0026] Specifically, the installation process of the solvent-resistant nanofiltration membrane of this utility model is as follows: First, insert one end of the first water distribution plate 22 of the membrane module 2 into the cylindrical housing 4, so that the first water distribution plate 22 contacts the annular boss 27, so that the annular boss 27 provides support for the first water distribution plate 22. Then, align the permeate outlet pipe 14 of the inlet end cap 3 with the central tube 19, and thread the permeate outlet pipe 14 and the central tube 19 through the internal thread 28 and the external thread 26 until the lower end of the permeate outlet pipe 14 is connected to the second water distribution plate 23. Waterproof tape can be wrapped between the internal thread 28 and the external thread 26 to improve the sealing effect. At this time, the side wall of the end cap housing 13 is located in the annular groove 17. Then, the elastic rubber ring 18, which is pre-fitted on the end cap housing 13, is pressed into the gap between the end cap housing 13 and the annular groove 17. The compression of the end cap housing 13 by the elastic rubber ring 18 strengthens the tightness of the contact between the end cap housing 13 and the cylindrical housing 4, and also facilitates the disassembly, maintenance, and replacement of the end cap housing 13.

[0027] The working process is as follows: the raw material to be treated enters the inlet cover 3 at the raw material inlet 16. Through the internal space of the inlet cover 3 and the buffer screen 15, the inlet pressure is relieved and the flow is dispersed. The raw material passes through the buffer screen 15 and enters the membrane module 2 for filtration. The permeate enters the tube through the water collection hole 20 on the central tube 19 and is discharged through the permeate outlet 14. The concentrate enters the outlet cover 6 through the first water separator 22 and is discharged through the concentrate outlet 7. After the nanofiltration membrane has been running for a period of time, the contents of the outlet cover 6 and the... Dirt will grow on the first water distribution plate 22, affecting the filtration effect. Therefore, by opening the sealing cover 12 on the water outlet end cover 6, the multi-hole spray pipe 11 is inserted into the cleaning pipe inlet 10 and fixed in the circular groove 9. By connecting the multi-hole spray pipe 11 to the water supply system, the inside of the water outlet end cover 6 and the first water distribution plate 22 can be flushed regularly. The flushing dirt is discharged through the concentrate outlet 7, extending the membrane replacement time. At the same time, after cleaning, the multi-hole spray pipe 11 is taken out and the cleaning pipe inlet 10 is sealed with the sealing cover 12.

[0028] It should be noted that the multi-hole water inlet pipe 11 can be a circular pipe with several water outlet holes opened around the circumference of the circular pipe for rinsing the inside of the water outlet end cap, or a spray head can be installed on the water outlet holes. Since the multi-hole water inlet pipe can achieve the function of multi-directional water spraying, many existing water spraying devices can achieve this, so its specific structure is not limited.

[0029] Furthermore, both the first water distribution plate 22 and the second water distribution plate 23 include a water distribution plate outer shell 29, a hollow connecting pipe 30 located inside the water distribution plate outer shell 29 and coaxially arranged, and a curved partition 31 fixedly arranged between the water distribution plate outer shell 29 and the hollow connecting pipe 30. The cross-section of the hollow connecting pipe 30 is trapezoidal.

[0030] Specifically, the two ends of the nanofiltration membrane element 21 are inserted into the first water distribution plate 22 and the second water distribution plate 23 respectively, and are in contact with the curved baffle 31. The nanofiltration membrane element 21 is glued to the side walls of the first water distribution plate 22 and the second water distribution plate 23. At the same time, the sealed end 24 of the central tube 19 is inserted into the hollow connecting tube 30 of the first water distribution plate 22 for fixation, and the open end 25 of the central tube 19 passes through the hollow connecting tube 30 of the second water distribution plate 23 and is threadedly connected to the permeate outlet pipe 14. In addition, the water distribution plate divides the raw material by setting the curved baffle 31, and the curved cross-section can effectively alleviate the inlet water pressure and The flow rate is reduced to decrease the inlet impact on the nanofiltration membrane element and improve its service life. At the same time, the cross-sectional structure of the hollow connecting pipe 30 is set as a trapezoidal structure, and the hollow connecting pipe 30 of the second water distribution plate 23 is set as an inverted trapezoidal structure. This allows the inflow space of the raw material to gradually increase when it enters the second water distribution plate 23, thus mitigating the impact of the inlet flow rate and pressure. The hollow connecting pipe 30 of the first water distribution plate 22 is set as a regular trapezoidal structure. This allows the inlet water to increase when the cleaning water is rinsed from bottom to top during the water spraying process of the multi-hole spray pipe 11. Combined with the curved baffle 31, this effectively reduces the impact of the cleaning spray on the membrane element.

[0031] Furthermore, two first sealing grooves 32 are provided on the outer wall of the water distribution plate housing 29, and a first sealing ring 33 is provided in the first sealing groove 32 for sealing between the water distribution plate housing 29 and the cylindrical housing 4. Two second sealing grooves 34 are provided on the inner wall of the hollow connecting pipe 30, and a second sealing ring 35 is provided in the second sealing groove 34 for sealing between the hollow connecting pipe 30 and the central pipe 19. A third sealing groove 48 is provided on the outer wall of the cylindrical housing 4 located above the annular groove 17, and a third sealing ring 49 is provided in the third sealing groove 48 for sealing between the cylindrical housing 4 and the water inlet end cap 3. By setting the sealing rings, the sealing performance of the entire nanofiltration membrane module can be greatly improved.

[0032] Furthermore, the nanofiltration membrane element 21 is formed by repeatedly stacking an inlet water guide net 36, a folded solvent-resistant nanofiltration membrane 37, and a product water guide net 38. The folded solvent-resistant nanofiltration membrane 37 includes an upper membrane sheet 39 and a lower membrane sheet 40. A crease 41 is provided between the upper membrane sheet 39 and the lower membrane sheet 40. The inlet water guide net 36 is located between the upper membrane sheet 39 and the lower membrane sheet 40. The product water guide net 38 is located on the upper membrane sheet 39. Each of the three free edges of the upper membrane sheet 39 is provided with an adhesive strip 42. The adhesive strip 42 is used to bond with the lower membrane sheet 40 of the adjacent solvent-resistant nanofiltration membrane 37 to form a membrane bag. The crease 41 is fixedly connected to the central tube 19. The product water guide net 38 ensures the normal flow of the product water channel, and the inlet water guide net 36 ensures that the water flow can reach the surface of the membrane bag evenly.

[0033] Furthermore, the nanofiltration membrane element 21 also includes an adhesive tape sleeve 43 for sealing and protecting the solvent-resistant nanofiltration membrane.

[0034] Specifically, the nanofiltration membrane element 21 is formed by fixing the folded end of the solvent-resistant nanofiltration membrane 37 parallel to the central tube 19, either by pressure-sensitive adhesive bonding or ultrasonic welding, and then winding it around the central tube 19. Finally, an adhesive tape cover 43 is wrapped around the outermost layer.

[0035] The filtration process is as follows: the raw material enters the inlet guide net 36 through the second water distribution plate 23, the permeate enters the membrane bag through the solvent-resistant nanofiltration membrane 37, the permeate is guided to the central tube 19 by the guiding effect of the product water guide net 38, and enters the central tube 19 through the water collection hole 20, and the concentrate flows out through the inlet guide net 36 at the first water distribution plate 22.

[0036] Among them, the solvent-resistant nanofiltration membrane is composed of a base membrane and a separation layer. It can be prepared by using sulfonated polyphenylsulfone as the base membrane, coating it with a layer of polyethyleneimine, and then crosslinking and modifying it; or by depositing polydiallyldimethylammonium chloride and sulfonated polyether ether ketone sequentially on the surface of a hydrolyzed polyacrylonitrile base membrane to prepare a solvent-resistant nanofiltration membrane, etc., all of which have good solvent resistance properties.

[0037] Furthermore, the buffer mesh 15 is provided with a through hole 44 for the liquid outlet pipe 14 to pass through, several buffer holes 45 for water flow buffering, and mounting holes 46 for fixing to the water inlet end cover 3. The side wall of the water inlet end cover 3 is provided with a mounting block 47, and the mounting block 47 is provided with a threaded hole (not shown) corresponding to the mounting hole 46. The buffer mesh 15 is fixed in the water inlet end cover 3 by the mounting hole 46 and the threaded hole bolt. The installation structure of the buffer mesh 15 is simple and easy to replace.

[0038] This invention effectively buffers inlet water pressure and flow by installing a buffer screen inside the inlet cap. Simultaneously, combined with the water distribution plate structure, it further disperses the inlet water pressure, reducing impact on the membrane element, effectively protecting it, and extending its service life. Furthermore, a cleaning pipe inlet is installed at the outlet cap, combined with a circular groove. When fouling occurs at the concentrate outlet, affecting membrane filtration, the sealing cap can be opened, and a multi-hole spray pipe can be fixed between the circular groove and the cleaning pipe inlet. Connecting the multi-hole spray pipe to the water supply system allows for regular flushing of the concentrate outlet water distribution plate, membrane, and outlet cap, thus improving the membrane element's service life.

[0039] It should be noted that the buffer mesh, permeate discharge pipe, mounting block, annular boss and other parts in this utility model are all made of corrosion-resistant materials or coated with acid and alkali resistant coatings to improve corrosion resistance and extend service life.

[0040] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A novel solvent-resistant nanofiltration membrane, characterized in that: The device includes a membrane housing, a membrane assembly fixedly disposed inside the membrane housing, and an inlet cap fixedly connected to the membrane housing. The membrane housing comprises a hollow cylindrical shell with an opening at its upper end and an outlet cap integrally formed at its lower end. The outlet cap has a concentrate outlet at its lower end. A circular protrusion with a circular groove is provided within the protrusion on its side wall. A cleaning pipe inlet corresponding to the circular groove is provided on the outlet cap. A multi-hole spray pipe is detachably installed between the circular groove and the cleaning pipe inlet, and the cleaning pipe inlet is threaded. The inlet cap has a sealing cap. The inlet cap includes a cap shell with a U-shaped cross-section, a permeate outlet pipe integrally and coaxially disposed through the cap shell, a buffer net fixedly disposed inside the cap shell, and a raw material inlet located above the buffer net. One end of the permeate outlet pipe inside the cap shell passes through the buffer net and is fixedly connected to the membrane assembly. The inner wall diameter at the opening of the cap shell is equal to the outer wall diameter of the cylindrical shell. An annular groove is provided on the upper outer wall of the cylindrical shell. The lower end of the cap shell is located in the annular groove. An elastic rubber ring is provided between the cap shell and the annular groove.

2. The novel solvent-resistant nanofiltration membrane according to claim 1, characterized in that: The membrane module includes a central tube, a water collection hole disposed on the central tube, a nanofiltration membrane element fixedly wound on the central tube, and a first water distribution plate and a second water distribution plate fixedly disposed at both ends of the nanofiltration membrane element. One end of the central tube is a sealed end, which is sealed and inserted into the first water distribution plate. The other end of the central tube is an open end, which penetrates the second water distribution plate. An external thread is provided on the outer wall of the open end located outside the second water distribution plate.

3. The novel solvent-resistant nanofiltration membrane according to claim 2, characterized in that: An annular boss is fixedly provided on the lower inner wall of the cylindrical shell, the first water distribution plate is located on the annular boss, and an internal thread matching the external thread is provided on the lower inner wall of the permeate outlet pipe. The membrane module is fixedly installed in the cylindrical shell through the annular boss and the permeate outlet pipe.

4. The novel solvent-resistant nanofiltration membrane according to claim 2, characterized in that: Both the first and second water distribution plates include a water distribution plate shell, a hollow connecting pipe located inside the water distribution plate shell and coaxially arranged, and a curved partition plate fixedly arranged between the water distribution plate shell and the hollow connecting pipe. The cross-section of the hollow connecting pipe is trapezoidal.

5. A novel solvent-resistant nanofiltration membrane according to claim 4, characterized in that: The outer wall of the water distribution plate shell is provided with two first sealing grooves, and a first sealing ring is provided in the first sealing groove for sealing between the water distribution plate shell and the cylindrical shell. The inner wall of the hollow connecting pipe is provided with two second sealing grooves, and a second sealing ring is provided in the second sealing groove for sealing between the hollow connecting pipe and the central pipe.

6. A novel solvent-resistant nanofiltration membrane according to claim 2, characterized in that: The nanofiltration membrane element is formed by repeatedly stacking an inlet water guide net, a folded solvent-resistant nanofiltration membrane, and a product water guide net. The folded solvent-resistant nanofiltration membrane includes an upper membrane sheet and a lower membrane sheet, with a crease between the upper and lower membrane sheets. The inlet water guide net is located between the upper and lower membrane sheets, and the product water guide net is located on the upper membrane sheet. Each of the three free edges of the upper membrane sheet is provided with an adhesive strip, which is used to bond with the lower membrane sheet of the adjacent solvent-resistant nanofiltration membrane to form a membrane bag. The crease is fixedly connected to the central tube.

7. A novel solvent-resistant nanofiltration membrane according to claim 6, characterized in that: The nanofiltration membrane element also includes an adhesive tape sleeve for sealing and protecting the solvent-resistant nanofiltration membrane.

8. The novel solvent-resistant nanofiltration membrane according to claim 1, characterized in that: The buffer mesh is provided with a through hole for the liquid outlet pipe to pass through, several buffer holes for water flow buffering, and mounting holes for fixing to the water inlet end cover. The side wall of the water inlet end cover is provided with a mounting block, and the mounting block is provided with threaded holes corresponding to the mounting holes. The buffer mesh is fixed inside the water inlet end cover by bolts through the mounting holes and threaded holes.

9. A novel solvent-resistant nanofiltration membrane according to claim 1, characterized in that: A third sealing groove is provided on the outer wall of the cylindrical shell located above the annular groove, and a third sealing ring is provided in the third sealing groove for sealing between the cylindrical shell and the water inlet end cap.

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