CN114130227A - Application of sulfated cellulose nanofibrils as nanofiltration membrane middle support layer - Google Patents
Application of sulfated cellulose nanofibrils as nanofiltration membrane middle support layer Download PDFInfo
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Abstract
The invention belongs to the technical field of advanced petrochemical new materials, relates to preparation of a nanofiltration membrane, and particularly relates to application of sulfated cellulose nanofibrils as a middle supporting layer of the nanofiltration membrane. The preparation method comprises the following steps: pretreating cellulose by using a eutectic solvent, and then carrying out combined superfine grinding mechanical treatment to obtain sulfated cellulose nanofibrils; preparing a middle support layer on the surface of a polyethersulfone microfiltration membrane by using sulfated cellulose nanofibrils in a filtering mode to obtain a filter membrane compound; and preparing a piperazinyl polyamide surface layer on the surface of the filter membrane compound through interfacial polymerization. The method disclosed by the invention is simple to operate, green and environment-friendly, and can effectively improve the permeation and separation performance of the nanofiltration membrane.
Description
Technical Field
The invention belongs to the technical field of advanced petrochemical new materials, relates to preparation of a nanofiltration membrane, and particularly relates to application of sulfated cellulose nanofibrils as a middle support layer of the nanofiltration membrane.
Background
The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.
The nanofiltration membrane consists of a porous substrate and a polyamide surface layer, the polyamide surface layer has large influence on the permeation and separation performance of the membrane according to the research of the inventor, and the polyamide surface layer is modified in a general method for increasing the separation efficiency of the nanofiltration membrane. However, the modification process for the polyamide surface layer is complicated.
Disclosure of Invention
In order to solve the defects of the prior art, the invention aims to provide the application of the sulfated cellulose nanofibrils as the middle support layer of the nanofiltration membrane, and the method has the advantages of simple operation, low cost, greenness and environmental protection, and can effectively improve the permeation and separation performance of the nanofiltration membrane.
In order to achieve the purpose, the technical scheme of the invention is as follows:
in one aspect, the use of a sulfated cellulose nanofibril as a middle support layer of a nanofiltration membrane comprising, in order, a porous substrate, the middle support layer and a polyamide surface layer.
The middle support layer of the nanofiltration membrane is generally arranged for adjusting the mechanical properties of the nanofiltration membrane, and therefore, in order to improve the mechanical properties of the nanofiltration membrane, the material of the middle support layer is generally a material with high mechanical properties, such as cadmium nanowires, carbon nanotubes, and the like. Firstly, after the cellulose nanofibrils are subjected to sulfation modification, sulfuric acid groups (-OSO) exist on the surface2OH) can adjust the hydrophilicity and the ridge-valley structure of the surface layer of the nanofiltration membrane, and meanwhile, the mechanical property of the nanofiltration membrane is excellent, so that the mechanical property of the nanofiltration membrane can be improved. Secondly, the invention adjusts the middle supporting layer of the nanofiltration membrane in order to improve the separation performance of the nanofiltration membrane(ii) a The research shows that the sulfated cellulose nanofibrils as the middle support layer of the nanofiltration membrane can greatly improve the separation performance of the nanofiltration membrane, and when the sulfated cellulose nanofibrils are used as the middle support layer of the nanofiltration membrane, for example, the rejection rate of sodium sulfate can be improved by more than 21 percent.
On the other hand, the surface of the polyethersulfone microfiltration membrane is sequentially provided with a middle supporting layer and a piperazinyl polyamide surface layer, and the middle supporting layer is made of sulfated cellulose nanofibrils.
In a third aspect, a method for preparing a nanofiltration membrane comprises the following steps:
pretreating cellulose by using a eutectic solvent, and then carrying out combined superfine grinding mechanical treatment to obtain sulfated cellulose nanofibrils;
preparing a middle support layer on the surface of a polyethersulfone microfiltration membrane by using sulfated cellulose nanofibrils in a filtering mode to obtain a filter membrane compound;
and preparing a piperazinyl polyamide surface layer on the surface of the filter membrane compound through interfacial polymerization.
In a fourth aspect, the nanofiltration membrane is applied to seawater desalination, wastewater treatment and/or brine softening.
Research shows that the nanofiltration membrane provided by the invention has excellent separation performance on salt, and the interception efficiency on sodium sulfate can reach 99.63%.
The invention has the beneficial effects that:
(1) the invention uses the sulfated cellulose nano-fibrils as the middle supporting layer, not only provides good mechanical support for the nanofiltration process, but also effectively improves the permeation and separation performance of the nanofiltration membrane.
(2) The method is simple to operate, green and environment-friendly, and the used sulfated cellulose nanofibrils are low in cost and environment-friendly, so that the method is beneficial to industrial production of the nanofiltration membrane.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
Figure 1 is a nanofiltration membrane prepared in example 1 of the present invention;
figure 2 is a nanofiltration membrane prepared in example 2 of the present invention;
figure 3 is a nanofiltration membrane prepared in example 3 of the present invention;
fig. 4 shows a nanofiltration membrane prepared in example 4 of the present invention.
Detailed Description
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
In view of the fact that the method for modifying the surface layer of polyamide is complicated by generally increasing the separation efficiency of the nanofiltration membrane, the invention provides the application of sulfated cellulose nanofibrils as the middle support layer of the nanofiltration membrane.
In a typical embodiment of the invention, there is provided the use of a sulfated cellulose nanofibrils as a middle support layer of a nanofiltration membrane comprising, in order, a porous substrate, the middle support layer and a polyamide surface layer. According to the invention, the sulfated cellulose nanofibrils are selected as the middle support layer of the nanofiltration membrane, firstly, after the cellulose nanofibrils are subjected to sulfation modification, sulfuric acid groups exist on the surface, the surface layer can be adjusted, and meanwhile, the mechanical property of the nanofiltration membrane is improved due to the excellent mechanical property. Secondly, researches show that the separation performance of the nanofiltration membrane can be greatly improved by taking the sulfated cellulose nanofibrils as a middle support layer of the nanofiltration membrane, and when the sulfated cellulose nanofibrils are taken as the middle support layer of the nanofiltration membrane for treating sodium sulfate, the rejection rate of the sodium sulfate can be improved by more than 21%.
The invention also provides a nanofiltration membrane, wherein a middle support layer and a piperazinyl polyamide surface layer are sequentially arranged on the surface of the polyethersulfone microfiltration membrane, and the middle support layer is made of sulfated cellulose nanofibrils.
In some examples of this embodiment, the degree of substitution of the sulfated cellulose nanofibrils is between 0.06 and 0.13. Research shows that the degree of substitution of the sulfated cellulose nanofibrils affects the separation performance of the nanofiltration membrane, and the separation performance of the degree of substitution is better; when the substitution degree is 0.085-0.0125, the separation performance is better; when the degree of substitution is 0.015-0.0125, the separation performance is more excellent.
In some embodiments of this embodiment, the piperazinyl polyamide skin layer is formed by the polycondensation of piperazine and trimesoyl chloride.
In some embodiments of this embodiment, the pore size of the polyethersulfone microfiltration membrane is between 0.20 and 0.25 μm. The diameter of the polyethersulfone microfiltration membrane is preferably 40-60 mm.
In a third embodiment of the present invention, a method for preparing a nanofiltration membrane is provided, which comprises the following steps:
pretreating cellulose by using a eutectic solvent, and then carrying out combined superfine grinding mechanical treatment to obtain sulfated cellulose nanofibrils;
preparing a middle support layer on the surface of a polyethersulfone microfiltration membrane by using sulfated cellulose nanofibrils in a filtering mode to obtain a filter membrane compound;
and preparing a piperazinyl polyamide surface layer on the surface of the filter membrane compound through interfacial polymerization.
In some examples of this embodiment, the eutectic solvent is prepared from sulfamic acid and glycerol. The molar ratio of sulfamic acid to glycerol is 1: 2.9-3.1.
In one or more embodiments, the molar ratio of sulfamic acid to cellulose is 1:10 to 20. The degree of substitution of the sulfated cellulose nanofibrils affects the separation performance of the nanofiltration membrane, and the main factors affecting the degree of substitution include time, temperature, molar ratio and the like. When the time and the temperature are fixed, the molar ratio is a key factor influencing the degree of substitution, and the separation performance of the nanofiltration membrane prepared by the sulfated cellulose nanofibrils with the obtained degree of substitution is higher.
In some examples of this embodiment, the temperature of the pretreatment with the eutectic solvent is 95 to 105 ℃ and the time is 85 to 95 min.
In some examples of this embodiment, the mode of filtration is vacuum filtration. The sulfated cellulose nano-fibrils can be better attached to the surface of the polyether sulfone microfiltration membrane.
The process for preparing the filter membrane compound comprises the following steps: adding sulfated cellulose nano-fibrils into water, uniformly dispersing to obtain a suspension, and then filtering to obtain a filter membrane compound. The concentration of the sulfated cellulose nanofibrils in the suspension is (6.0-8.0) x 108g/m3。
In some examples of this embodiment, the process of interfacial polymerization is: firstly, soaking the filter membrane compound into a piperazine water solution, taking out the filter membrane compound, draining, drying, soaking the filter membrane compound into an organic solution of trimesoyl chloride, taking out and drying.
In one or more embodiments, the mass concentration of the piperazine aqueous solution is 0.20-0.30 wt%, and the mass concentration of the organic solution of trimesoyl chloride is 0.45-0.55 wt%. The piperazinyl polyamide surface layer prepared under the concentration is controlled by the middle supporting layer, so that the obtained nanofiltration membrane has better separation performance.
In one or more embodiments, the immersion time in the piperazine aqueous solution is 1.5-2.5 min, and the immersion time in the organic solution of trimesoyl chloride is 1.5-2.5 min. Under the interfacial polymerization parameter, the obtained piperazinyl polyamide surface layer can cooperate with the middle supporting layer to generate a nanofiltration membrane with better separation performance.
In one or more embodiments, the immersion is performed until the piperazine aqueous solution is removed, and the water is drained in a vertical manner. The drainage efficiency is higher. The influence on the combination of the middle supporting layer and the polyether sulfone microfiltration membrane is avoided.
In one or more embodiments, after the piperazine aqueous solution is immersed and taken out, the water is drained for 3-5 min, and the drying time is 25-35 min. And (3) immersing the piperazine into a piperazine water solution, taking out the piperazine water solution, and drying the piperazine water solution at room temperature, wherein the room temperature is indoor environment temperature and is generally 15-30 ℃. The drying after the organic solution immersed in the trimesoyl chloride is taken out is heating drying. The heating temperature is 55-65 ℃.
In a fourth embodiment of the invention, the application of the nanofiltration membrane in seawater desalination, wastewater treatment and/or brine softening is provided.
In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.
Example 1
(1) Deionized water was filtered by means of vacuum filtration through a polyethersulfone microfiltration membrane having a diameter of 50mm and a pore size of 0.22 μm.
(2) Preparing an anhydrous piperazine aqueous solution and a trimesoyl chloride n-hexane solution: preparing anhydrous piperazine into a solution with the mass concentration of 0.25 wt% by using deionized water, and preparing trimesoyl chloride into a solution with the mass concentration of 0.5 wt% by using normal hexane.
(3) And (2) immersing the filtered polyethersulfone microfiltration membrane into the prepared anhydrous piperazine aqueous solution with the mass concentration of 0.25 wt% for 2min, taking out the sulfated cellulose nanofibrils and the polyethersulfone microfiltration membrane compound from the anhydrous piperazine aqueous solution after the completion of the time, vertically draining for 4min to remove redundant solution, drying at room temperature for 30min, immersing the sulfated cellulose nanofibrils and the polyethersulfone microfiltration membrane compound into a trimesoyl chloride n-hexane solution for 2min, taking out the sulfated cellulose nanofibrils and the polyethersulfone microfiltration membrane compound from the trimesoyl chloride n-hexane solution after the time is up, and drying in a 60 ℃ drying oven for 30min to obtain the nanofiltration membrane, wherein the nanofiltration membrane is shown in figure 1.
And (3) detecting the separation performance of the nanofiltration membrane by using a cross-flow device self-made in a laboratory. The effective filtration area of the membrane was 12.56cm2To stabilize the pressure at the time of the test, the salt filtration test is usually preceded by a pair of deionized water at room temperatureThe membrane is pre-compressed for 2h at a pressure of 4 bar. At a pressure of 2bar, Na was added in a concentration of 1000ppm2SO4The solution was filtered for 30min, and then the filtrate was collected, and the concentration of the salt solution was measured using a conductivity meter.
Water penetration (F, L.m)-2·h-1) The calculation formula of (2) is as follows:
wherein V is the volume (L) of the filtrate; a is the effective filtration area (m)2) (ii) a t is the filtration time (h).
The salt rejection (R,%) is calculated as:
wherein, CpIs the concentration of the filtrate; cfIs the concentration of the feed solution.
The aperture of the nanofiltration membrane prepared by the embodiment is 2.7691nm, and the nanofiltration membrane is Na2SO4The retention rate of (a) was 79.87%.
Example 2
(1) Preparation of sulfated cellulose nanofibrils with a degree of substitution of 0.07: sulfated cellulose nanofibrils are obtained by means of pretreatment of sulfamic acid and glyceryl eutectic solvent and mechanical treatment of superfine grinding. The molar ratio of sulfamic acid to glycerol is 1:3, the molar ratio of sulfamic acid to cellulose is 1:10, the pretreatment temperature is 100 ℃, the pretreatment time is 90min, the pulp fiber is prepared into an aqueous solution with the concentration of 1.0 wt% after being pretreated by a eutectic solvent, and then the aqueous solution is mechanically treated by a superfine pulverizer to finally prepare the sulfated cellulose nanofibrils.
(2) Preparation of sulfated cellulose nanofibrils and polyethersulfone microfiltration membrane complex: sulfated cellulose nanofibrils were placed at a support layer density of 7.6 x 108g/m3Preparing a suspension with a certain concentration by using deionized water, and then filtering the suspension by adopting a vacuum filtration modeAnd preparing the sulfated cellulose nano-fibrils and the polyether sulfone microfiltration membrane compound on the surface of the polyether sulfone microfiltration membrane with the diameter of 50mm and the pore diameter of 0.22 mu m.
(3) Preparing an anhydrous piperazine aqueous solution and a trimesoyl chloride n-hexane solution: preparing anhydrous piperazine into a solution with the mass concentration of 0.25 wt% by using deionized water, and preparing trimesoyl chloride into a solution with the mass concentration of 0.5 wt% by using normal hexane.
(4) Interfacial polymerization: and (2) immersing the prepared sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound into the prepared anhydrous piperazine aqueous solution with the mass concentration of 0.25 wt% for 2min, taking the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound out of the anhydrous piperazine aqueous solution after the time is finished, vertically draining for 4min to remove redundant solution, drying at room temperature for 30min, immersing the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound into a trimesoyl chloride n-hexane solution for 2min, taking the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound out of the trimesoyl chloride n-hexane solution after the time is up, and drying in a 60 ℃ drying oven for 30min to obtain the nanofiltration membrane, wherein the nanofiltration membrane is shown in figure 2.
And (3) detecting the separation performance of the nanofiltration membrane by using a cross-flow device self-made in a laboratory. The effective filtration area of the membrane was 12.56cm2To stabilize the pressure at the time of the test, the membrane was typically pre-stressed with deionized water at room temperature for 2h at a pressure of 4bar prior to the salt filtration test. At a pressure of 2bar, Na was added in a concentration of 1000ppm2SO4The solution was filtered for 30min, and then the filtrate was collected, and the concentration of the salt solution was measured using a conductivity meter.
Water penetration (F, L.m)-2·h-1) The calculation formula of (2) is as follows:
wherein V is the volume (L) of the filtrate; a is the effective filtration area (m)2) (ii) a t is the filtration time (h).
The salt rejection (R,%) is calculated as:
wherein, CpIs the concentration of the filtrate; cfIs the concentration of the feed solution.
The aperture of the nanofiltration membrane prepared by the embodiment is 1.7656nm, and the nanofiltration membrane is Na2SO4The retention rate of (a) was 96.79%.
Example 3
(1) Preparation of sulfated cellulose nanofibrils with a degree of substitution of 0.09: the sulfated cellulose nanofibrils are obtained by adopting a mode of sulfamic acid and glyceryl eutectic solvent pretreatment and superfine grinding mechanical treatment, wherein the molar ratio of sulfamic acid to glycerin is 1:3, the molar ratio of sulfamic acid to cellulose is 1:15, the pretreatment temperature is 100 ℃, and the pretreatment time is 90 min. After pretreatment by eutectic solvent, preparing paper pulp fiber into 1.0 wt% aqueous solution, and then mechanically processing by a superfine pulverizer to finally prepare the sulfated cellulose nanofibrils.
(2) Preparation of sulfated cellulose nanofibrils and polyethersulfone microfiltration membrane complex: sulfated cellulose nanofibrils were placed at a support layer density of 7.6 x 108g/m3Deionized water is used for preparing suspension with a certain concentration, and then the suspension is filtered to the surface of a polyethersulfone microfiltration membrane with the diameter of 50mm and the pore diameter of 0.22 mu m by adopting a vacuum filtration mode, so as to prepare the sulfated cellulose nanofibrils and the polyethersulfone microfiltration membrane compound.
(3) Preparing an anhydrous piperazine aqueous solution and a trimesoyl chloride n-hexane solution: preparing anhydrous piperazine into a solution with the mass concentration of 0.25 wt% by using deionized water, and preparing trimesoyl chloride into a solution with the mass concentration of 0.5 wt% by using normal hexane.
(4) Interfacial polymerization: and (3) immersing the prepared sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound into the prepared anhydrous piperazine aqueous solution with the mass concentration of 0.25 wt% for 2min, taking the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound out of the anhydrous piperazine aqueous solution after the time is finished, vertically draining for 4min to remove redundant solution, drying at room temperature for 30min, immersing the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound into a trimesoyl chloride n-hexane solution for 2min, taking the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound out of the trimesoyl chloride n-hexane solution after the time is up, and drying in a 60 ℃ drying oven for 30min to obtain the nanofiltration membrane, wherein the nanofiltration membrane is shown in figure 3.
And (3) detecting the separation performance of the nanofiltration membrane by using a cross-flow device self-made in a laboratory. The effective filtration area of the membrane was 12.56cm2To stabilize the pressure at the time of the test, the membrane was typically pre-stressed with deionized water at room temperature for 2h at a pressure of 4bar prior to the salt filtration test. At a pressure of 2bar, Na was added in a concentration of 1000ppm2SO4The solution was filtered for 30min, and then the filtrate was collected, and the concentration of the salt solution was measured using a conductivity meter.
Water penetration (F, L.m)-2·h-1) The calculation formula of (2) is as follows:
wherein V is the volume (L) of the filtrate; a is the effective filtration area (m)2) (ii) a t is the filtration time (h).
The salt rejection (R,%) is calculated as:
wherein, CpIs the concentration of the filtrate; cfIs the concentration of the feed solution.
The aperture of the nanofiltration membrane prepared by the embodiment is 1.5264nm, and the nanofiltration membrane is Na2SO4The retention rate of (D) was 99.63%.
Example 4
(1) Preparation of sulfated cellulose nanofibrils with a degree of substitution of 0.12: the sulfated cellulose nanofibrils are obtained by adopting a mode of sulfamic acid and glyceryl eutectic solvent pretreatment and superfine grinding mechanical treatment, wherein the molar ratio of sulfamic acid to glycerin is 1:3, the molar ratio of sulfamic acid to cellulose is 1:20, the pretreatment temperature is 100 ℃, and the pretreatment time is 90 min. After pretreatment by eutectic solvent, preparing paper pulp fiber into 1.0 wt% aqueous solution, and then mechanically processing by a superfine pulverizer to finally prepare the sulfated cellulose nanofibrils.
(2) Preparation of sulfated cellulose nanofibrils and polyethersulfone microfiltration membrane complex: sulfated cellulose nanofibrils were placed at a support layer density of 7.6 x 108g/m3Deionized water is used for preparing suspension with a certain concentration, and then the suspension is filtered to the surface of a polyethersulfone microfiltration membrane with the diameter of 50mm and the pore diameter of 0.22 mu m by adopting a vacuum filtration mode, so as to prepare the sulfated cellulose nanofibrils and the polyethersulfone microfiltration membrane compound.
(3) Preparing an anhydrous piperazine aqueous solution and a trimesoyl chloride n-hexane solution: preparing anhydrous piperazine into a solution with the mass concentration of 0.25 wt% by using deionized water, and preparing trimesoyl chloride into a solution with the mass concentration of 0.5 wt% by using normal hexane.
(4) Interfacial polymerization: and (3) immersing the prepared sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound into the prepared anhydrous piperazine aqueous solution with the mass concentration of 0.25 wt% for 2min, taking the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound out of the anhydrous piperazine aqueous solution after the time is finished, vertically draining for 4min to remove redundant solution, drying at room temperature for 30min, immersing the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound into a trimesoyl chloride n-hexane solution for 2min, taking the sulfated cellulose nanofibrils and polyether sulfone microfiltration membrane compound out of the trimesoyl chloride n-hexane solution after the time is up, and drying in a 60 ℃ drying oven for 30min to obtain the nanofiltration membrane, wherein the nanofiltration membrane is shown in figure 4.
And (3) detecting the separation performance of the nanofiltration membrane by using a cross-flow device self-made in a laboratory. The effective filtration area of the membrane was 12.56cm2To stabilize the pressure at the time of the test, the membrane was typically pre-stressed with deionized water at room temperature for 2h at a pressure of 4bar prior to the salt filtration test. At a pressure of 2bar, Na was added in a concentration of 1000ppm2SO4The solution was filtered for 30min, thenThe filtrate was then collected and the concentration of the salt solution was measured using a conductivity meter.
Water penetration (F, L.m)-2·h-1) The calculation formula of (2) is as follows:
wherein V is the volume (L) of the filtrate; a is the effective filtration area (m)2) (ii) a t is the filtration time (h).
The salt rejection (R,%) is calculated as:
wherein, CpIs the concentration of the filtrate; cfIs the concentration of the feed solution.
The aperture of the nanofiltration membrane prepared by the embodiment is 1.5260nm, and the nanofiltration membrane is Na2SO4The retention rate of (a) was 98.91%.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The application of sulfated cellulose nanofibrils as a middle support layer of a nanofiltration membrane comprises a porous substrate, the middle support layer and a polyamide surface layer in sequence.
2. A middle supporting layer and a piperazinyl polyamide surface layer are sequentially arranged on the surface of a nanofiltration membrane of polyether sulfone, and the nanofiltration membrane is characterized in that the middle supporting layer is made of sulfated cellulose nanofibrils.
3. Nanofiltration membrane according to claim 2, wherein the degree of substitution of the sulfated cellulose nanofibrils is between 0.06 and 0.13; preferably 0.085-0.0125; further preferably 0.015-0.0125.
4. Nanofiltration membrane according to claim 2, wherein the piperazinyl polyamide surface layer is formed by polycondensation of piperazine and trimesoyl chloride.
5. The preparation method of the nanofiltration membrane is characterized by comprising the following steps:
pretreating cellulose by using a eutectic solvent, and then carrying out combined superfine grinding mechanical treatment to obtain sulfated cellulose nanofibrils;
preparing a middle support layer on the surface of a polyethersulfone microfiltration membrane by using sulfated cellulose nanofibrils in a filtering mode to obtain a filter membrane compound;
and preparing a piperazinyl polyamide surface layer on the surface of the filter membrane compound through interfacial polymerization.
6. The method for preparing nanofiltration membrane according to claim 5, wherein the eutectic solvent is prepared from sulfamic acid and glycerol;
preferably, the molar ratio of the sulfamic acid to the cellulose is 1: 10-20;
or the temperature of the deep eutectic solvent pretreatment is 95-105 ℃, and the time is 85-95 min.
7. The nanofiltration membrane preparation method according to claim 5, wherein the interfacial polymerization process comprises: firstly, soaking the filter membrane compound into a piperazine water solution, taking out the filter membrane compound, draining, drying, soaking the filter membrane compound into an organic solution of trimesoyl chloride, taking out and drying.
8. The nanofiltration membrane preparation method according to claim 7, wherein the mass concentration of the piperazine aqueous solution is 0.20 to 0.30 wt%, and the mass concentration of the trimesoyl chloride organic solution is 0.45 to 0.55 wt%.
9. The method for preparing nanofiltration membrane according to claim 7, wherein the immersion time in the piperazine aqueous solution is 1.5-2.5 min, and the immersion time in the organic solution of trimesoyl chloride is 1.5-2.5 min;
or, after the piperazine water solution is immersed and taken out, the water is drained for 3-5 min, and the drying time is 25-35 min.
10. Use of a nanofiltration membrane according to any one of claims 2 to 4 or obtained by the preparation method according to any one of claims 5 to 9 in desalination of sea water, treatment of wastewater and/or softening of brine.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112142863A (en) * | 2020-09-15 | 2020-12-29 | 齐鲁工业大学 | Method for modifying cellulose by reactive eutectic solvent |
| CN115090123A (en) * | 2022-07-01 | 2022-09-23 | 浙江理工大学 | Preparation and application of nanofiltration membrane based on positively charged nanomaterial intermediate layer |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108771978A (en) * | 2018-07-09 | 2018-11-09 | 海南立昇净水科技实业有限公司 | It is a kind of to utilize nano cellulose crystal blending and modifying ultrafiltration membrane preparation method |
| CN110141974A (en) * | 2019-05-17 | 2019-08-20 | 李文国 | A kind of nano-cellulose-composite nanometer filtering film (CNF-NF) and preparation method thereof |
| CN111229053A (en) * | 2020-02-17 | 2020-06-05 | 中国科学院苏州纳米技术与纳米仿生研究所 | High-flux nanofiltration membrane, and preparation method and application thereof |
| CN112267157A (en) * | 2020-10-29 | 2021-01-26 | 齐鲁工业大学 | Preparation method of cellulose nano-fibrils modified based on reactive eutectic solvent |
| CN112452164A (en) * | 2020-10-22 | 2021-03-09 | 哈尔滨工业大学 | Two-step modified composite nanofiltration membrane containing cellulose nanocrystal intermediate layer and dopamine in-situ modification layer and preparation method thereof |
| US20210178337A1 (en) * | 2017-12-01 | 2021-06-17 | Aji Pallikunnel Mathew | Double-layered cellulose nanofiber material, method of manufacturing, membranes, and use thereof |
-
2021
- 2021-12-10 CN CN202111510252.5A patent/CN114130227B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210178337A1 (en) * | 2017-12-01 | 2021-06-17 | Aji Pallikunnel Mathew | Double-layered cellulose nanofiber material, method of manufacturing, membranes, and use thereof |
| CN108771978A (en) * | 2018-07-09 | 2018-11-09 | 海南立昇净水科技实业有限公司 | It is a kind of to utilize nano cellulose crystal blending and modifying ultrafiltration membrane preparation method |
| CN110141974A (en) * | 2019-05-17 | 2019-08-20 | 李文国 | A kind of nano-cellulose-composite nanometer filtering film (CNF-NF) and preparation method thereof |
| CN111229053A (en) * | 2020-02-17 | 2020-06-05 | 中国科学院苏州纳米技术与纳米仿生研究所 | High-flux nanofiltration membrane, and preparation method and application thereof |
| CN112452164A (en) * | 2020-10-22 | 2021-03-09 | 哈尔滨工业大学 | Two-step modified composite nanofiltration membrane containing cellulose nanocrystal intermediate layer and dopamine in-situ modification layer and preparation method thereof |
| CN112267157A (en) * | 2020-10-29 | 2021-01-26 | 齐鲁工业大学 | Preparation method of cellulose nano-fibrils modified based on reactive eutectic solvent |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112142863A (en) * | 2020-09-15 | 2020-12-29 | 齐鲁工业大学 | Method for modifying cellulose by reactive eutectic solvent |
| CN115090123A (en) * | 2022-07-01 | 2022-09-23 | 浙江理工大学 | Preparation and application of nanofiltration membrane based on positively charged nanomaterial intermediate layer |
| CN115090123B (en) * | 2022-07-01 | 2024-02-20 | 浙江理工大学 | Nanofiltration membrane preparation based on positively charged nanomaterial intermediate layer and application thereof |
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