Modified non-woven fabric, filter element containing modified non-woven fabric, preparation method of modified non-woven fabric and water purifier

Abstract

The invention discloses a modified non-woven fabric, a filter element containing the modified non-woven fabric, a preparation method of the filter element and a water purifier. The modified non-woven fabric is characterized in that a modified layer is arranged on the non-woven fabric, and the modified layer is formed by first molecular chains and second molecular chains which are alternated; the first molecular chain comprises a structure formed by combining an amine monomer, a cross-linking agent and a charged polymer through chemical bonds; the second molecular chain comprises a structure formed by combining an amine monomer, a cross-linking agent and an uncharged polymer through chemical bonds; the ratio of the molecular weight of the charged polymer to the molecular weight of the non-charged polymer is 1: (1-1.5). The modified non-woven fabric can continuously and efficiently remove heavy metal, retain mineral substances and inhibit bacterial breeding, when the modified non-woven fabric is used in a filter element, the size of the filter element cannot be too large, the water flux of the filter element cannot be affected, on the contrary, structural parts of a filter element combination part can be reduced, and the cost of the filter element is reduced.

Description

Technical Field

[0001] The present invention relates to the field of water purification, and in particular to a modified non-woven fabric, a filter element containing the same, a preparation method thereof, and a water purifier. Background Art

[0002] In existing technology, reverse osmosis filters are primarily used to remove heavy metals from water. Reverse osmosis filters work by applying a certain amount of pressure to the water, forcing water molecules and ionic mineral elements to pass through the reverse osmosis membrane. However, most inorganic salts, organic matter, bacteria, and viruses in the water, including heavy metals, cannot pass through the membrane. While reverse osmosis filters can effectively remove heavy metals and improve the quality of drinking water, they also remove some minerals from the water. Health experts have pointed out and practice has proven that purified water without minerals is not suitable for long-term drinking, especially for the elderly, pregnant women, and children. This is because human metabolism requires minerals, and drinking water is one of the primary sources of minerals and various trace elements. Nanofiltration filters are a water treatment technology whose main feature is their ability to appropriately retain minerals beneficial to the human body. Their retention capacity for ions of different valence states varies significantly, but they also retain some heavy metals.

[0003] In order to achieve the technical effect of removing heavy metals and retaining minerals, the water purifiers currently on the market use a composite method of nanofiltration filter elements and NSP filter elements (membrane chromatography filter elements). First, the use of multiple filter elements in a composite method will result in a larger filter element size, complex water paths, greater water resistance, and lower flow rate. Second, the composite filter element method requires the use of multiple filter elements, and the composite filter element requires the use of structural components, resulting in higher overall costs. Finally, in the water purifier, the NSP filter element is located at the rear end of the nanofiltration filter element, making it easily exposed to bacteria entering from the water purifier faucet, thus posing a risk of bacterial growth. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the separation membrane or filter element in the prior art that it cannot achieve the effects of removing heavy metals, retaining minerals and inhibiting bacterial growth while ensuring high water flux and low cost, and to provide a modified non-woven fabric, a filter element containing the same, a preparation method thereof, and a water purifier. The modified non-woven fabric can continuously and efficiently remove heavy metals, retain minerals and inhibit bacterial growth. When the modified non-woven fabric is used in a filter element, it will not cause the filter element to be too large, nor will it affect the water flux of the filter element itself. Instead, it can reduce the structural parts of the filter element assembly part and reduce the cost of the filter element. The filter element containing the modified non-woven fabric takes into account the ability of the reverse osmosis filter element to efficiently remove heavy metals and the ability of the nanofiltration filter element to retain minerals, and can also inhibit bacterial growth.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] The present invention provides a modified non-woven fabric, wherein a modified layer is provided on the non-woven fabric, and the modified layer is formed by alternating first molecular chains and second molecular chains;

[0007] The first molecular chain includes a structure formed by chemical bonds between an amine monomer, a cross-linking agent and a charged polymer;

[0008] The second molecular chain includes an amine monomer, a cross-linking agent, and a non-charged polymer formed by chemical bonds;

[0009] The ratio of the molecular weights of the charged polymer to the uncharged polymer is 1:(1-1.5).

[0010] Preferably, the amine monomer is a combination of one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, ethylenediamine and hexamethylenediamine.

[0011] Preferably, the cross-linking agent is a combination of one or more of glutaraldehyde, tannic acid and glycerol triglycidyl ether.

[0012] Preferably, the charged polymer is polyethyleneimine and / or chitosan.

[0013] Preferably, the non-charged polymer is polyhexamethyleneguanidine.

[0014] Preferably, the molecular weight of the charged polymer is 10-70 kDa.

[0015] Further preferably, the molecular weight of the charged polymer is 40-70 kDa.

[0016] Preferably, the molecular weight of the non-charged polymer is 10-100 kDa.

[0017] Further preferably, the molecular weight of the non-charged polymer is 50-100 kDa.

[0018] Preferably, the molecular weight ratio of the charged polymer to the uncharged polymer is 1:(1.1-1.5), more preferably (7-8):10.

[0019] Preferably, the ratio of the molecular weights of the charged polymer to the uncharged polymer is (7-8):10.

[0020] Preferably, the molecular weight of the charged polymer is 70 kDa, and the molecular weight of the uncharged polymer is 100 kDa.

[0021] The present invention also provides a method for preparing a modified non-woven fabric, which comprises the following steps:

[0022] S1. The non-woven fabric is sequentially immersed in a solution containing an amine monomer and a solution containing a crosslinking agent;

[0023] S2. The non-woven fabric obtained in step S1 is immersed in a mixed solution of a charged polymer and a non-charged polymer;

[0024] The ratio of the molecular weights of the charged polymer to the uncharged polymer is 1:(1-1.5).

[0025] Preferably, in step S1, the amine monomer is a combination of one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, ethylenediamine and hexamethylenediamine.

[0026] Preferably, in step S1, the mass fraction of the amine monomer is 1-5%, calculated as the mass fraction of the amine monomer to the total mass of the solution containing the amine monomer.

[0027] Preferably, in step S1, the solvent of the solution containing amine monomers is water.

[0028] Preferably, in step S1, the non-woven fabric is taken out and washed after being soaked in the solution.

[0029] More preferably, pure water is used for the cleaning.

[0030] Preferably, in step S1, the temperature at which the non-woven fabric is immersed in the solution containing the amine monomer is 70-90°C.

[0031] Preferably, in step S1, the non-woven fabric is immersed in the solution containing the amine monomer for 2-4 hours.

[0032] Preferably, in step S1, the cross-linking agent is a combination of one or more of glutaraldehyde, tannic acid and glycerol triglycidyl ether.

[0033] Preferably, in step S1, the mass fraction of the cross-linking agent is 0.5-2%, calculated as the mass fraction of the cross-linking agent to the total mass of the cross-linking agent solution.

[0034] Preferably, in step S1, the solvent of the solution containing the cross-linking agent is water.

[0035] Preferably, in step S1, the non-woven fabric is immersed in the solution containing the cross-linking agent at a temperature of 20-40°C.

[0036] Preferably, in step S1, the non-woven fabric is immersed in the solution containing the cross-linking agent for 10-30 minutes.

[0037] Preferably, in step S2, the charged polymer is polyethyleneimine and / or chitosan.

[0038] Preferably, in step S2, the non-charged polymer is polyhexamethylene guanidine.

[0039] Preferably, in step S2, the solvent of the mixed solution of the charged polymer and the uncharged polymer is water.

[0040] Preferably, in step S2, the soaking further includes the steps of washing and drying.

[0041] More preferably, pure water is used for the cleaning.

[0042] Preferably, in step S2, the mass fraction of the charged polymer is 1-5%, calculated as the mass fraction of the charged polymer to the total mass of the mixed solution.

[0043] Preferably, in step S2, the mass fraction of the non-charged polymer is 1-5%, calculated as the mass fraction of the non-charged polymer to the total mass of the mixed solution.

[0044] Preferably, in step S2, the molecular weight of the charged polymer is 10-70 kDa.

[0045] Further preferably, the molecular weight of the charged polymer is 40-70 kDa.

[0046] Preferably, in step S2, the molecular weight of the non-charged polymer is 10-100 kDa.

[0047] Further preferably, the molecular weight of the non-charged polymer is 50-100 kDa.

[0048] Preferably, the molecular weight ratio of the charged polymer to the uncharged polymer is 1:(1.1-1.5), more preferably (7-8):10.

[0049] Preferably, in step S2, the soaking temperature is 20-40°C.

[0050] Preferably, in step S2, the soaking time is 30-60 minutes.

[0051] The present invention also provides a modified non-woven fabric, which is prepared by using the above-mentioned method for preparing the modified non-woven fabric.

[0052] The present invention also provides a filter element, which comprises the modified non-woven fabric.

[0053] Preferably, the filter element comprises a central tube, a filter membrane group, an upper end cover and a lower end cover;

[0054] The filter membrane group includes a plurality of membrane units spaced apart along the outer circumference of the central tube;

[0055] The opening directions of the diaphragm units are the same, and each diaphragm unit includes two single diaphragms connected in sequence; each single diaphragm is folded to form a long diaphragm and a short diaphragm, and the length of the long diaphragm is greater than the length of the short diaphragm; the short diaphragms of adjacent single diaphragms in each diaphragm unit are connected to each other, and the long diaphragms of adjacent single diaphragms of adjacent diaphragm units are connected to each other; the space between the inner side surfaces of the long diaphragms of each single diaphragm and the inner side surfaces of the short diaphragms forms a raw water channel; the space between the inner side surfaces of the long diaphragms of the single diaphragms that are attached to each diaphragm unit forms a wastewater channel; the space between the outer side surfaces of the two attached short diaphragms of each diaphragm unit and the space between the outer side surfaces of the two attached long diaphragms of adjacent diaphragm units both form a clean water channel;

[0056] Each of the membrane units further comprises an intermediate guide cloth and a partition net, wherein the partition net is arranged in the raw water channel, and the intermediate guide cloth is arranged in the clean water channel;

[0057] The filter membrane group further includes a modified non-woven fabric and a bottom guide fabric; the bottom guide fabric is wound along the circumference of the central tube; the modified non-woven fabric is wound along the circumference of the bottom guide fabric, one end of the modified non-woven fabric is fixed to the outer circumferential surface of the bottom guide fabric, and the other end of the modified non-woven fabric extends outward to cover the plurality of membrane units, and is wound and fixed along the axial direction of the central tube to form a winding body;

[0058] The upper end of the coiled body is partially sealed by a first sealing tape, and a raw water inlet is formed on a side of the coiled body close to the central pipe;

[0059] The lower end of the wound body is completely sealed by a second sealing tape, so that the raw water entering from the raw water inlet flows out along the raw water channel to the outer peripheral surface of the wound body; the outer peripheral surface of the wound body is provided with an adhesive tape, and the adhesive tape is evenly provided with concentrated water outlets for the concentrated water to flow out;

[0060] The upper end cover and the lower end cover are respectively sleeved on both ends of the winding body.

[0061] Further preferably, the length of the modified non-woven fabric is 3-10 m.

[0062] Further preferably, the length of the short diaphragm is 10%-50% of the length of the long diaphragm.

[0063] Further preferably, the length of the raw water inlet accounts for 10%-90% of the flat length of the wound body.

[0064] Further preferably, the length of the concentrated water outlet is shorter than the flattened length of the winding body.

[0065] Further preferably, the bottom guide cloth is wound around the central tube 2-3 times along the circumference.

[0066] The present invention also provides a water purifier, which comprises the filter element as described above.

[0067] The positive progress effect of the present invention is:

[0068] (1) The modified nonwoven fabric of the present invention has the functions of adsorbing heavy metals and inhibiting bacterial growth. The heavy metal adsorption material is introduced to efficiently remove heavy metals, and the bactericidal material is introduced to efficiently kill bacteria and inhibit bacterial growth.

[0069] (2) The modified nonwoven fabric of the present invention also has an automatic adjustment function. When the main function is to adsorb heavy metals, on the one hand, it can efficiently adsorb and remove heavy metals, and on the other hand, it can protect the bactericidal material; when the main function is to kill bacteria, on the one hand, it can efficiently kill bacteria and prevent bacterial growth, and on the other hand, it can protect the adsorption material and prevent the adsorption material from being contaminated and ineffective due to bacteria.

[0070] (3) The filter element of the present invention achieves a high degree of composite of the nanofiltration filter element and the modified non-woven fabric, optimizes the filter element space, reduces the filter element volume, effectively optimizes the water flow path, and reduces the filter element cost.

[0071] (4) The filter element of the present invention takes into account both the ability of the reverse osmosis filter element to efficiently remove heavy metals and the ability of the nanofiltration filter element to retain minerals. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 Schematic diagram of the filter element structure of Examples 1 to 4.

[0073] Figure 2 Schematic diagram of the top view of the filter element in the expanded state of Examples 1 to 4.

[0074] Figure 3 Schematic diagram of the structure of the filter element in the wound state of Examples 1 to 4.

[0075] Figure 4 Schematic diagram of the microstructure of the modified non-woven fabric in the operating state of the filter element of Examples 1 to 3.

[0076] Figure 5 Schematic diagram of the microstructure of the modified non-woven fabric in the static state of the filter element of Examples 1 to 3.

[0077] Description of reference numerals:

[0078] Center tube 10

[0079] Bottom diversion cloth 11

[0080] Modified non-woven fabric 12

[0081] Diaphragm unit 13

[0082] Short diaphragm 20

[0083] Long diaphragm 21

[0084] First sealing tape 22

[0085] Second sealing tape 23

[0086] Net 24

[0087] Middle guide cloth 25

[0088] Raw water import 30

[0089] Concentrated water outlet 31

[0090] Tape 40

[0091] The first molecular chain 50

[0092] Second molecular chain 51

[0093] Non-woven fabric 52 DETAILED DESCRIPTION

[0094] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0095] Example 1

[0096] 1. Preparation process of modified non-woven fabric:

[0097] 1) Soak the non-woven fabric in a 1 wt% diethylenetriamine solution, react at 70° C. for 2 h, and then take it out and rinse it with pure water.

[0098] 2) The non-woven fabric cleaned in step 1) was immersed in a 0.5% glutaraldehyde solution, reacted at 20° C. for 10 minutes, and then taken out and cleaned with pure water.

[0099] 3) soaking the cleaned non-woven fabric in step 2) in a solution containing 1% polyethyleneimine and 1% polyhexamethyleneguanidine, reacting at 20° C. for 30 minutes, removing the non-woven fabric, washing it with pure water, and drying it to obtain a modified non-woven fabric; wherein the molecular weight of the polyethyleneimine is 10 kDa, and the molecular weight of the polyhexamethyleneguanidine is 15 kDa.

[0100] The modified non-woven fabric 52 is provided with a modified layer, which is formed by alternating first molecular chains 50 and second molecular chains 51; the first molecular chains 50 include a structure formed by chemical bonds between diethylenetriamine, glutaraldehyde and polyethyleneimine; the second molecular chains 51 include a structure formed by chemical bonds between diethylenetriamine, glutaraldehyde and polyhexamethyleneguanidine, and the molecular weight ratio of polyethyleneimine to polyhexamethyleneguanidine is 1:1.5.

[0101] 2. The structure of the filter element:

[0102] like Figure 1-3 As shown in the structural diagram of , the filter element includes a central tube 10, a filter membrane group, an upper end cover and a lower end cover; the filter membrane group includes a plurality of membrane units 13 spaced apart along the outer circumferential surface of the central tube 10.

[0103] The opening directions of each diaphragm unit 13 are the same, and each diaphragm unit 13 includes two single diaphragms connected in sequence; each single diaphragm is folded to form a long diaphragm 21 and a short diaphragm 20, and the length of the short diaphragm 20 is 10% of the length of the long diaphragm 21; the short diaphragms 20 of adjacent single diaphragms in each diaphragm unit 13 are connected to each other, and the long diaphragms 21 of adjacent single diaphragms in adjacent diaphragm units 13 are connected to each other; the space between the inner side surfaces of the long diaphragm 21 of each single diaphragm and the inner side surfaces of the short diaphragm 20 form a raw water channel; the space between the inner side surfaces of the long diaphragms 21 of the single diaphragms that are attached to each diaphragm unit 13 forms a wastewater channel; the space between the outer side surfaces of the two short diaphragms 20 that are attached to each diaphragm unit 13, and the space between the outer side surfaces of the two long diaphragms 21 that are attached to adjacent diaphragm units 13 both form a clean water channel.

[0104] Each membrane unit 13 further includes an intermediate guide cloth 25 and a partition net 24 . The partition net 24 is arranged in the raw water channel, and the intermediate guide cloth 25 is arranged in the clean water channel.

[0105] The filter membrane group includes a modified non-woven fabric 12 and a bottom guide fabric 11; the bottom guide fabric 11 is wound around the circumference of the central tube 10 twice; the modified non-woven fabric 12 is wound around the circumference of the bottom guide fabric 11, one end of the modified non-woven fabric 12 is fixed to the outer peripheral surface of the bottom guide fabric 11, and the other end of the modified non-woven fabric 12 extends outward to cover a plurality of membrane units 13, and is wound and fixed along the axial direction of the central tube 10 to form a wound body. The length of the modified non-woven fabric 12 is 3 meters.

[0106] The upper end of the coil is partially sealed by a first sealing tape 22 and a raw water inlet 30 is formed on the side of the coil close to the central tube 10. The length of the raw water inlet 30 accounts for 10% of the flat length of the coil.

[0107] The lower end of the winding body is completely sealed by the second sealing tape 23 so that the raw water entering from the raw water inlet 30 flows out along the raw water channel to the outer peripheral surface of the winding body; the outer peripheral surface of the winding body is circumferentially provided with a tape 40, and the tape 40 is evenly provided with concentrated water outlets 31 for the concentrated water to flow out. The length of the concentrated water outlet 31 is shorter than the flat length of the winding body.

[0108] The upper end cover and the lower end cover are respectively sleeved on the two ends of the winding body.

[0109] Example 2

[0110] 1. Preparation process of modified non-woven fabric:

[0111] 1) Soak the non-woven fabric in a 3 wt% triethylenetetramine solution, react at 80°C for 3 hours, and then remove and rinse with pure water;

[0112] 2) Soaking the cleaned non-woven fabric in step 1) in a 1% tannic acid solution, reacting at 30° C. for 20 minutes, and then removing the non-woven fabric and washing it with pure water;

[0113] 3) soaking the cleaned non-woven fabric in step 2) in a solution containing 3% polyethyleneimine and 3% polyhexamethyleneguanidine, reacting at 30° C. for 50 minutes, taking out and washing with pure water, and drying to obtain a modified non-woven fabric; wherein the molecular weight of polyethyleneimine is 40 kDa and the molecular weight of polyhexamethyleneguanidine is 50 kDa.

[0114] The modified non-woven fabric 52 is provided with a modified layer, which is formed by alternating first molecular chains 50 and second molecular chains 51; the first molecular chains 50 include a structure formed by chemical bonds between triethylenetetramine, tannic acid and polyethyleneimine; the second molecular chains 51 include a structure formed by chemical bonds between triethylenetetramine, tannic acid and polyhexamethyleneguanidine.

[0115] 2. The structure of the filter element:

[0116] like Figure 1-3 As shown in the structural diagram of , the filter element includes a central tube 10, a filter membrane group, an upper end cover and a lower end cover; the filter membrane group includes a plurality of membrane units 13 spaced apart along the outer circumferential surface of the central tube 10.

[0117] The opening directions of each diaphragm unit 13 are the same, and each diaphragm unit 13 includes two single diaphragms connected in sequence; each single diaphragm is folded to form a long diaphragm 21 and a short diaphragm 20, and the length of the short diaphragm 20 is 30% of the length of the long diaphragm 21; the short diaphragms 20 of adjacent single diaphragms in each diaphragm unit 13 are connected to each other, and the long diaphragms 21 of adjacent single diaphragms in adjacent diaphragm units 13 are connected to each other; the space between the inner side surfaces of the long diaphragm 21 of each single diaphragm and the inner side surfaces of the short diaphragm 20 form a raw water channel; the space between the inner side surfaces of the long diaphragms 21 of the single diaphragms that are attached to each diaphragm unit 13 forms a wastewater channel; the space between the outer side surfaces of the two short diaphragms 20 that are attached to each diaphragm unit 13, and the space between the outer side surfaces of the two long diaphragms 21 that are attached to adjacent diaphragm units 13 both form a clean water channel.

[0118] Each membrane unit 13 further includes an intermediate guide cloth 25 and a partition net 24 . The partition net 24 is arranged in the raw water channel, and the intermediate guide cloth 25 is arranged in the clean water channel.

[0119] The filter membrane group includes a modified non-woven fabric 12 and a bottom guide fabric 11; the bottom guide fabric 11 is wound around the circumference of the central tube 10 twice; the modified non-woven fabric 12 is wound around the circumference of the bottom guide fabric 11, one end of the modified non-woven fabric 12 is fixed to the outer peripheral surface of the bottom guide fabric 11, and the other end of the modified non-woven fabric 12 extends outward to cover a plurality of membrane units 13, and is wound and fixed along the axial direction of the central tube 10 to form a wound body. The length of the modified non-woven fabric 12 is 5 meters.

[0120] The upper end of the coil is partially sealed by a first sealing tape 22 and a raw water inlet 30 is formed on the side of the coil close to the central tube 10. The length of the raw water inlet 30 accounts for 50% of the flat length of the coil.

[0121] The lower end of the winding body is completely sealed by the second sealing tape 23 so that the raw water entering from the raw water inlet 30 flows out along the raw water channel to the outer peripheral surface of the winding body; the outer peripheral surface of the winding body is circumferentially provided with a tape 40, and the tape 40 is evenly provided with concentrated water outlets 31 for the concentrated water to flow out. The length of the concentrated water outlet 31 is shorter than the flat length of the winding body.

[0122] The upper end cover and the lower end cover are respectively sleeved on the two ends of the winding body.

[0123] Example 3

[0124] 1. Preparation process of modified non-woven fabric:

[0125] 1) Soak the non-woven fabric in a 5 wt% ethylenediamine solution, react at 90°C for 4 hours, and then remove and rinse with pure water;

[0126] 2) Soaking the cleaned non-woven fabric in step 1) in a 2% glycerol triglycidyl ether solution at 40° C. for 30 minutes, then removing the non-woven fabric and washing it with pure water;

[0127] 3) soaking the cleaned non-woven fabric in step 2) in a solution containing 5% polyethyleneimine and 5% polyhexamethyleneguanidine, reacting at 40° C. for 60 minutes, removing the non-woven fabric, washing it with pure water, and drying it to obtain a modified non-woven fabric; wherein the molecular weight of the polyethyleneimine is 70 kDa and the molecular weight of the polyhexamethyleneguanidine is 100 kDa.

[0128] The modified non-woven fabric 52 is provided with a modified layer, which is formed by alternating first molecular chains 50 and second molecular chains 51; the first molecular chains 50 include a structure formed by chemical bonds between ethylenediamine, glycerol triglycidyl ether and polyethyleneimine; the second molecular chains 51 include a structure formed by chemical bonds between ethylenediamine, glycerol triglycidyl ether and polyhexamethyleneguanidine.

[0129] 2. The structure of the filter element:

[0130] like Figure 1-3 As shown in the structural diagram of , the filter element includes a central tube 10, a filter membrane group, an upper end cover and a lower end cover; the filter membrane group includes a plurality of membrane units 13 spaced apart along the outer circumferential surface of the central tube 10.

[0131] The opening directions of each diaphragm unit 13 are the same, and each diaphragm unit 13 includes two single diaphragms connected in sequence; each single diaphragm is folded to form a long diaphragm 21 and a short diaphragm 20, and the length of the short diaphragm 20 is 50% of the length of the long diaphragm 21; the short diaphragms 20 of adjacent single diaphragms in each diaphragm unit 13 are connected to each other, and the long diaphragms 21 of adjacent single diaphragms in adjacent diaphragm units 13 are connected to each other; the space between the inner side surfaces of the long diaphragm 21 of each single diaphragm and the inner side surfaces of the short diaphragm 20 form a raw water channel; the space between the inner side surfaces of the long diaphragms 21 of the single diaphragms that are attached to each diaphragm unit 13 forms a wastewater channel; the space between the outer side surfaces of the two short diaphragms 20 that are attached to each diaphragm unit 13, and the space between the outer side surfaces of the two long diaphragms 21 that are attached to adjacent diaphragm units 13 both form a clean water channel.

[0132] Each membrane unit 13 further includes an intermediate guide cloth 25 and a partition net 24 . The partition net 24 is arranged in the raw water channel, and the intermediate guide cloth 25 is arranged in the clean water channel.

[0133] The filter membrane group includes a modified non-woven fabric 12 and a bottom guide fabric 11; the bottom guide fabric 11 is wound three times along the circumference of the central tube 10; the modified non-woven fabric 12 is wound along the circumference of the bottom guide fabric 11, one end of the modified non-woven fabric 12 is fixed to the outer peripheral surface of the bottom guide fabric 11, and the other end of the modified non-woven fabric 12 extends outward to cover multiple membrane units 13, and is wound and fixed along the axial direction of the central tube 10 to form a wound body. The length of the modified non-woven fabric 12 is 10 meters.

[0134] The upper end of the coil is partially sealed by a first sealing tape 22 and a raw water inlet 30 is formed on the side of the coil close to the central tube 10. The length of the raw water inlet 30 accounts for 90% of the flat length of the coil.

[0135] The lower end of the winding body is completely sealed by the second sealing tape 23 so that the raw water entering from the raw water inlet 30 flows out along the raw water channel to the outer peripheral surface of the winding body; the outer peripheral surface of the winding body is circumferentially provided with a tape 40, and the tape 40 is evenly provided with concentrated water outlets 31 for the concentrated water to flow out. The length of the concentrated water outlet 31 is shorter than the flat length of the winding body.

[0136] The upper end cover and the lower end cover are respectively sleeved on the two ends of the winding body.

[0137] Example 4

[0138] 1. Preparation process of modified non-woven fabric:

[0139] 1) Soak the non-woven fabric in a 1 wt% diethylenetriamine solution, react at 70° C. for 2 h, and then take out and rinse with pure water.

[0140] 2) The non-woven fabric cleaned in step 1) was immersed in a 0.5% glutaraldehyde solution, reacted at 20° C. for 10 minutes, and then taken out and cleaned with pure water.

[0141] 3) soaking the cleaned non-woven fabric in step 2) in a solution containing 1% polyethyleneimine and 1% polyhexamethyleneguanidine, reacting at 20° C. for 30 minutes, taking out and washing with pure water, and drying to obtain a modified non-woven fabric; wherein the molecular weight of polyethyleneimine is 10 kDa and the molecular weight of polyhexamethyleneguanidine is 10 kDa.

[0142] The modified non-woven fabric 52 is provided with a modified layer, which is formed by alternating first molecular chains 50 and second molecular chains 51; the first molecular chains 50 include a structure formed by chemical bonds between diethylenetriamine, glutaraldehyde and polyethyleneimine; the second molecular chains 51 include a structure formed by chemical bonds between diethylenetriamine, glutaraldehyde and polyhexamethyleneguanidine, and the ratio of the molecular weights of polyethyleneimine to polyhexamethyleneguanidine is 1:1.

[0143] 2. The structure of the filter element:

[0144] like Figure 1-3 As shown in the structural diagram of , the filter element includes a central tube 10, a filter membrane group, an upper end cover and a lower end cover; the filter membrane group includes a plurality of membrane units 13 spaced apart along the outer circumferential surface of the central tube 10.

[0145] The opening directions of each diaphragm unit 13 are the same, and each diaphragm unit 13 includes two single diaphragms connected in sequence; each single diaphragm is folded to form a long diaphragm 21 and a short diaphragm 20, and the length of the short diaphragm 20 is 10% of the length of the long diaphragm 21; the short diaphragms 20 of adjacent single diaphragms in each diaphragm unit 13 are connected to each other, and the long diaphragms 21 of adjacent single diaphragms in adjacent diaphragm units 13 are connected to each other; the space between the inner side surfaces of the long diaphragm 21 of each single diaphragm and the inner side surfaces of the short diaphragm 20 form a raw water channel; the space between the inner side surfaces of the long diaphragms 21 of the single diaphragms that are attached to each diaphragm unit 13 forms a wastewater channel; the space between the outer side surfaces of the two short diaphragms 20 that are attached to each diaphragm unit 13, and the space between the outer side surfaces of the two long diaphragms 21 that are attached to adjacent diaphragm units 13 both form a clean water channel.

[0146] Each membrane unit 13 further includes an intermediate guide cloth 25 and a partition net 24 . The partition net 24 is arranged in the raw water channel, and the intermediate guide cloth 25 is arranged in the clean water channel.

[0147] The filter membrane group includes a modified non-woven fabric 12 and a bottom guide fabric 11; the bottom guide fabric 11 is wound around the circumference of the central tube 10 twice; the modified non-woven fabric 12 is wound around the circumference of the bottom guide fabric 11, one end of the modified non-woven fabric 12 is fixed to the outer peripheral surface of the bottom guide fabric 11, and the other end of the modified non-woven fabric 12 extends outward to cover a plurality of membrane units 13, and is wound and fixed along the axial direction of the central tube 10 to form a wound body. The length of the modified non-woven fabric 12 is 3 meters.

[0148] The upper end of the coil is partially sealed by a first sealing tape 22 and a raw water inlet 30 is formed on the side of the coil close to the central tube 10. The length of the raw water inlet 30 accounts for 10% of the flat length of the coil.

[0149] The lower end of the winding body is completely sealed by the second sealing tape 23 so that the raw water entering from the raw water inlet 30 flows out along the raw water channel to the outer peripheral surface of the winding body; the outer peripheral surface of the winding body is circumferentially provided with a tape 40, and the tape 40 is evenly provided with concentrated water outlets 31 for the concentrated water to flow out. The length of the concentrated water outlet 31 is shorter than the flat length of the winding body.

[0150] The upper end cover and the lower end cover are respectively sleeved on the two ends of the winding body.

[0151] Comparative Example 1

[0152] The structure of the filter element is the same as that of Example 1, except that the non-woven fabric is not modified.

[0153] Effect Example 1

[0154] The filter elements of Examples 1 to 4 and Comparative Example 1 were subjected to the following tests:

[0155] 1. Heavy metal test:

[0156] 1) Prepare heavy metal solution: Prepare heavy metal solution according to GB30307 requirements;

[0157] 2) Heavy metal removal effect test: Pass the prepared heavy metal solution into the filter element, take 10ml of the filtrate after stabilization; at the same time, take 10ml of the original solution;

[0158] 3) Heavy metal solution concentration test: Use atomic absorption spectrometry to test the heavy metal concentrations of the filtrate and the original solution, which are recorded as C1 and C2;

[0159] 4) Calculate heavy metal removal rate:

[0160]

[0161] The specific test results are shown in Table 1.

[0162] Table 1 Comparison of heavy metal removal rates

[0163]

[0164] As can be seen from Table 1, the heavy metal removal capability of the filter element prepared by the method in Comparative Example 1 is far inferior to that of Examples 1 to 4 of the present application.

[0165] 2. Heavy metal removal life test

[0166] 1) Prepare heavy metal solution: Prepare heavy metal solution according to GB30307 requirements;

[0167] 2) Heavy metal life test: Pass the prepared heavy metal solution into the filter element, take 10mL of the filtrate after a certain amount of water flow; at the same time, take 10mL of the original solution;

[0168] 3) Heavy metal solution concentration test: Use atomic absorption spectrometry to test the heavy metal concentrations of the filtrate and the original solution, which are recorded as C1 and C2;

[0169] 4) Calculate heavy metal removal rate:

[0170]

[0171] 5) Heavy Metal Removal Life: When the heavy metal removal rate is less than 80%, the life is terminated. The water flow rate at this time is recorded as the heavy metal removal life. Specific test results are shown in Table 2.

[0172] Table 2 Heavy metal removal life

[0173]

[0174] As shown in Table 2, the heavy metal removal life of the filter elements of Examples 1 to 4 is higher than 12.9 tons, and they have the effect of continuously removing heavy metals.

[0175] 3. Mineral retention rate test:

[0176] 1) Prepare mineral solution: Prepare mineral solution according to GB30307 requirements;

[0177] 2) Mineral removal effect test: Pass the prepared mineral solution into the filter element, and take 50 ml of the filtrate after stabilization; at the same time, take 50 ml of the original solution; potassium ion retention rate is determined using potassium chloride solution; calcium ion retention rate is determined using calcium chloride solution; sodium ion retention rate is determined using sodium chloride solution; magnesium ion retention rate is determined using magnesium chloride solution; lithium ion retention rate is determined using lithium chloride solution; bicarbonate retention rate is determined using sodium bicarbonate solution. The above are single measurements.

[0178] 3) Mineral solution concentration test: Use a conductivity meter to test the mineral concentration of the filtrate and the original solution, which are recorded as C3 and C4;

[0179] 4) Calculate the mineral retention rate:

[0180]

[0181] The specific test results are shown in Table 3.

[0182] Table 3 Comparison of mineral retention rates

[0183]

[0184] As can be seen from Table 3, the filter elements of Examples 1 to 4 have a mineral retention capacity similar to that of the filter element of Comparative Example 1 while efficiently removing heavy metals, and are able to retain some minerals.

[0185] 4. Non-woven fabric sterilization test

[0186] The sterilization rate test was conducted using the film-applying method specified in GB 21551.2-2010 (Particular requirements for antimicrobial materials with antibacterial, sterilization, and purification functions for household and similar electrical appliances). See Table 4 for the specific test results.

[0187] Table 4 Sterilization rate of modified non-woven fabrics

[0188]

[0189] As can be seen from Table 4, the filter elements of Examples 1 to 4 have a very good sterilization effect, with a sterilization rate of more than 97% against Escherichia coli and Staphylococcus aureus. The sterilization rate of Example 3 against Escherichia coli and Staphylococcus aureus reaches 99.99%, while the filter element of Comparative Example 1 has no sterilization function.

[0190] Figure 4 Figure 2 is a schematic diagram of the microstructure of the modified nonwoven fabric during operation of the filter elements of Examples 1-3. During operation, the total dissolved solids (TDS) in the water is relatively low, and the first molecular chains 50 are stretched due to electrostatic effects, making them longer than the second molecular chains 51. At this point, the modified nonwoven fabric primarily functions to adsorb heavy metals, efficiently removing them while also protecting the sterilizing material.

[0191] Figure 5 Figure 3 is a schematic diagram of the microstructure of the modified non-woven fabric in the static state of the filter elements of Examples 1 to 3. In the static state, due to diffusion and dialysis, ions on the nanofiltration surface gradually diffuse into the modified non-woven fabric, resulting in a relatively high TDS in the water. The electrostatic effect within the first molecular chain 50 is shielded, leaving it in a free state, and its length is shorter than that of the second molecular chain 51. At this time, the modified non-woven fabric mainly functions to kill bacteria, effectively preventing bacterial growth, and protecting the adsorbent material from becoming ineffective due to bacterial contamination.

Claims

1. A modified nonwoven fabric, characterized in that: A modified layer is provided on the non-woven fabric, wherein the modified layer is formed by alternating first molecular chains and second molecular chains; The first molecular chain includes a structure formed by chemical bonds between an amine monomer, a cross-linking agent and a charged polymer; The second molecular chain includes an amine monomer, a cross-linking agent, and a non-charged polymer formed by chemical bonds; The ratio of the molecular weights of the charged polymer to the uncharged polymer is 1:(1-1.5).

2. The modified nonwoven fabric according to claim 1, characterized in that The amine monomer is a combination of one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, ethylenediamine and hexamethylenediamine; and / or, the cross-linking agent is a combination of one or more of glutaraldehyde, tannic acid, and glycerol triglycidyl ether; And / or, the charged polymer is polyethyleneimine and / or chitosan; And / or, the non-charged polymer is polyhexamethylene guanidine; and / or, the molecular weight of the charged polymer is 10-70 kDa; Preferably, the molecular weight of the charged polymer is 40-70 kDa; and / or, the molecular weight of the non-charged polymer is 10-100 kDa; Preferably, the molecular weight of the non-charged polymer is 50-100 kDa; And / or, the molecular weight ratio of the charged polymer to the uncharged polymer is 1:(1.1-1.5), preferably (7-8):10; And / or, the molecular weight of the charged polymer is 70 kDa, and the molecular weight of the uncharged polymer is 100 kDa.

3. A method for preparing a modified nonwoven fabric, characterized in that: It includes the following steps: S1. The non-woven fabric is sequentially immersed in a solution containing an amine monomer and a solution containing a crosslinking agent; S2. The non-woven fabric obtained in step S1 is immersed in a mixed solution of a charged polymer and a non-charged polymer; The ratio of the molecular weights of the charged polymer to the uncharged polymer is 1:(1-1.5).

4. The method for preparing the modified nonwoven fabric according to claim 3, wherein: In step S1: the amine monomer is a combination of one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, ethylenediamine and hexamethylenediamine; and / or, the mass fraction of the amine monomer is 1-5%, calculated as the mass fraction of the amine monomer to the total mass of the solution containing the amine monomer; and / or, the solvent of the solution containing amine monomers is water; And / or, after the non-woven fabric is soaked in the solution, the steps of taking it out and washing it are also included; Preferably, pure water is used for cleaning; and / or, the temperature at which the nonwoven fabric is immersed in the solution containing the amine monomer is 70-90° C.; And / or, the non-woven fabric is immersed in the solution containing the amine monomer for 2-4 hours.

5. The method for preparing the modified nonwoven fabric according to claim 3, wherein: In step S1: the cross-linking agent is a combination of one or more of glutaraldehyde, tannic acid and glycerol triglycidyl ether; and / or, the mass fraction of the cross-linking agent is 0.5-2%, calculated as the mass fraction of the cross-linking agent to the total mass of the cross-linking agent solution; and / or, the solvent of the solution containing the cross-linking agent is water; and / or, the nonwoven fabric is immersed in the solution containing the crosslinking agent at a temperature of 20-40° C.; And / or, the non-woven fabric is immersed in the solution containing the cross-linking agent for 10-30 minutes.

6. The method for preparing the modified nonwoven fabric according to claim 3, wherein: In step S2: the charged polymer is polyethyleneimine and / or chitosan; And / or, the non-charged polymer is polyhexamethylene guanidine; And / or, the solvent of the mixed solution of the charged polymer and the uncharged polymer is water; And / or, the soaking step further includes the steps of washing and drying; Preferably, pure water is used for cleaning; and / or, the mass fraction of the charged polymer is 1-5%, calculated as the mass fraction of the charged polymer to the total mass of the mixed solution; and / or, the mass fraction of the non-charged polymer is 1-5%, calculated as the mass fraction of the non-charged polymer to the total mass of the mixed solution; and / or, the molecular weight of the charged polymer is 10-70 kDa; Preferably, the molecular weight of the charged polymer is 40-70 kDa; and / or, the molecular weight of the non-charged polymer is 10-100 kDa; Preferably, the molecular weight of the non-charged polymer is 50-100 kDa; And / or, the molecular weight ratio of the charged polymer to the uncharged polymer is 1:(1.1-1.5), preferably (7-8):10; And / or, the soaking temperature is 20-40°C; And / or, the soaking time is 30-60 minutes.

7. A modified nonwoven fabric, characterized in that: The modified nonwoven fabric is prepared by the method for preparing the modified nonwoven fabric according to any one of claims 3 to 6.

8. A filter element, characterized in that: The filter element comprises the modified non-woven fabric according to any one of claims 1, 2 and 7.

9. The filter element according to claim 8, characterized in that The filter element comprises a central tube, a filter membrane group, an upper end cover and a lower end cover; The filter membrane group includes a plurality of membrane units spaced apart along the outer circumference of the central tube; The opening directions of the diaphragm units are the same, and each diaphragm unit includes two single diaphragms connected in sequence; each single diaphragm is folded to form a long diaphragm and a short diaphragm, and the length of the long diaphragm is greater than the length of the short diaphragm; the short diaphragms of adjacent single diaphragms in each diaphragm unit are connected to each other, and the long diaphragms of adjacent single diaphragms of adjacent diaphragm units are connected to each other; the space between the inner side surfaces of the long diaphragms of each single diaphragm and the inner side surfaces of the short diaphragms forms a raw water channel; the space between the inner side surfaces of the long diaphragms of the single diaphragms that are attached to each diaphragm unit forms a wastewater channel; the space between the outer side surfaces of the two attached short diaphragms of each diaphragm unit and the space between the outer side surfaces of the two attached long diaphragms of adjacent diaphragm units both form a clean water channel; Each of the membrane units further comprises an intermediate guide cloth and a partition net, wherein the partition net is arranged in the raw water channel, and the intermediate guide cloth is arranged in the clean water channel; The filter membrane group further includes a modified non-woven fabric and a bottom guide fabric; the bottom guide fabric is wound along the circumference of the central tube; the modified non-woven fabric is wound along the circumference of the bottom guide fabric, one end of the modified non-woven fabric is fixed to the outer circumferential surface of the bottom guide fabric, and the other end of the modified non-woven fabric extends outward to cover the plurality of membrane units, and is wound and fixed along the axial direction of the central tube to form a winding body; The upper end of the coiled body is partially sealed by a first sealing tape, and a raw water inlet is formed on a side of the coiled body close to the central pipe; The lower end of the wound body is completely sealed by a second sealing tape, so that the raw water entering from the raw water inlet flows out along the raw water channel to the outer peripheral surface of the wound body; the outer peripheral surface of the wound body is provided with an adhesive tape, and the adhesive tape is evenly provided with concentrated water outlets for the concentrated water to flow out; The upper end cover and the lower end cover are respectively sleeved on both ends of the winding body; Preferably, the length of the modified non-woven fabric is 3-10m; Preferably, the length of the short diaphragm is 10%-50% of the length of the long diaphragm; Preferably, the length of the raw water inlet accounts for 10%-90% of the flat length of the coiled body; Preferably, the length of the concentrated water outlet is shorter than the flat length of the winding body; Preferably, the bottom guide cloth is wound around the central tube 2-3 times along the circumference.

10. A water purifier, characterized in that: The water purifier comprises the filter element according to claim 8 or claim 9.

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