CN113797763A - Cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation and preparation method and application thereof - Google Patents
Cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation and preparation method and application thereof Download PDFInfo
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
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- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
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- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
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- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Abstract
The invention discloses a cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation and a preparation method and application thereof, wherein the nanofiltration membrane comprises an ultrafiltration base membrane which is coated and modified by codeposition of dopamine and carboxymethyl cellulose and a gel layer which is of a compact three-dimensional network structure and is constructed on the surface of the modified ultrafiltration base membrane by utilizing twice cross-linking reactions of carboxymethyl cellulose under the action of a cross-linking agent, the thickness of the nanofiltration membrane is 110nm, the pore diameter of the nanofiltration membrane is 1.38nm, the ultrafiltration base membrane is one or more of a polyvinylidene fluoride ultrafiltration membrane, a polyether sulfone ultrafiltration membrane, a polysulfone ultrafiltration membrane and a polyimide ultrafiltration membrane, the thickness of the ultrafiltration base membrane is 100-400 mu m, and the pore diameter of the ultrafiltration base membrane is 4.24 nm.
Description
Technical Field
The invention belongs to the technical field of loose nanofiltration membranes, and particularly relates to a cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation, and a preparation method and application thereof.
Background
Textile wastewater is usually prepared from dye and inorganic salt (such as NaCl and Na)2SO4) Different types of surfactants, suspended solid particles, acids, bases and other auxiliary chemicals are among the more difficult industrial waste waters to treat. China, as a strong textile country, produces a large amount of textile wastewater every year. The direct discharge of textile wastewater poses serious hazards to the environment and human health, and therefore, the treatment of textile wastewater is extremely important for environmental protection and water resource recycling.
Nanofiltration membranes (NF), also known as Loose reverse osmosis membranes (membranes), are an important component of separation membranes with a cut-off molecular weight between 200 and 1000Da, and have been receiving increasing attention in the last few years due to their high water flux, low operating pressure and high rejection of multivalent ions. Compared with the traditional nanofiltration membrane, the loose nanofiltration membrane has a looser epidermal layer, the aperture is between that of nanofiltration and ultrafiltration, the loose nanofiltration membrane has high retention rate on dye, and simultaneously, a large amount of inorganic salt can permeate through the loose nanofiltration membrane, so that the loose nanofiltration membrane becomes one of important technologies for treating textile wastewater. However, in practical application, the membrane pollution caused by the feed liquid can reduce the separation performance of the loose nanofiltration membrane, and therefore, the preparation of the loose nanofiltration membrane with high permeability, high selectivity and long-acting anti-pollution performance to realize long-acting separation of the dye and the salt becomes a problem of great concern.
Patent document CN110449048A discloses a nanofiltration membrane, which is composed of a base membrane, an intermediate layer, and a selective separation layer, which are sequentially compounded; the base film is prepared by an electrostatic spinning method, and polyethyleneimine is added into the intermediate layer. The nanofiltration membrane is mainly applied to textile wastewater treatment, and the water flux of the membrane is about 30L/m2H.bar, dye retention 98.5%.
Patent document CN112827370A discloses a high-flux composite nanofiltration membrane, which is an all-carbon selective separation layer assembled by compounding carboxylated carbon nanotubes and partially reduced graphene oxide on a porous polymer support layer by means of vacuum filtration. The interception of the nanofiltration membrane to dye can reach more than 99 percent, and the pure water flux of the membrane is 80L/m2·h·bar。
Although the rejection rate of the nanofiltration membrane dyes disclosed in the above two patent documents can achieve good effect, in order to further improve the wastewater treatment efficiency, the water flux of the membrane needs to be further improved, and how to obtain a loose nanofiltration membrane with high permeability, high selectivity and long-term anti-fouling performance, a dense separation layer on the membrane surface is crucial.
Disclosure of Invention
In view of the above disadvantages, the first object of the present invention is to provide a cellulose gel layer modified high-flux loose nanofiltration membrane for dye separation;
the second purpose of the invention is to provide a preparation method of the cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation;
the third purpose of the invention is to provide the application of the cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation in dye desalination.
In order to achieve the purpose, the invention adopts the following technical scheme:
a cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation comprises an ultrafiltration base membrane which is coated and modified by co-deposition of dopamine and carboxymethyl cellulose and a gel layer which is of a compact three-dimensional network structure and is constructed on the surface of the modified ultrafiltration base membrane by using carboxymethyl cellulose through two cross-linking reactions under the action of a cross-linking agent, wherein the thickness of the nanofiltration membrane is 110nm, and the pore diameter of the nanofiltration membrane is 1.38 nm.
Further, the ultrafiltration basal membrane is one or more of a polyvinylidene fluoride ultrafiltration membrane, a polyether sulfone ultrafiltration membrane, a polysulfone ultrafiltration membrane and a polyimide ultrafiltration membrane.
Further, the ultrafiltration membrane is a polyvinylidene fluoride ultrafiltration membrane, the thickness of the ultrafiltration membrane is 100-400 mu m, and the pore diameter is 4.24 nm.
Further, the method comprises the following specific steps:
1) preparing an ultrafiltration membrane base membrane: sequentially adding the dried membrane preparation material, PEG, LiCl and NMP into a three-neck flask, stirring for 8-12 h at the temperature of 60-80 ℃ to obtain a uniform membrane casting solution, standing and defoaming, scraping the uniform membrane casting solution on a glass plate by using a membrane scraper, soaking the glass plate in a solidification solution, and preparing an ultrafiltration membrane basement membrane by an NIPS phase inversion method;
2) co-depositing dopamine and cellulose to modify an ultrafiltration membrane base membrane: soaking the ultrafiltration membrane base membrane obtained in the step 1) in 20-50 mL of Tris buffer solution containing 0.5-2 g/L cellulose and 0.5-2 g/L dopamine DA, placing the Tris buffer solution in a shaking table at a constant speed, shaking for 1-4 h, carrying out codeposition coating modification, and after the reaction is finished, washing the membrane by using ethanol solution containing epichlorohydrin ECH to obtain a modified ultrafiltration membrane base membrane for later use;
3) preparation of a loose nanofiltration membrane:
preparing a cellulose modified solution: taking 0.5g/L-10g/L cellulose water solution, adding AgNO with the molar ratio of 3:13And NaBH4Obtaining cellulose modified liquid;
fixing the modified ultrafiltration membrane base membrane in the step 2) in a round box with the front side facing upwards, pouring 20-50 mL of cellulose modification liquid on the surface of the modified ultrafiltration membrane base membrane, adding 1-5 mL of ethanol solution with the ECH content of 5%, and performing crosslinking reaction in an oven at 60-80 ℃ for 1-5 h to obtain a membrane for the first crosslinking reaction after the reaction is finished;
and (2) fixing the membrane subjected to the first cross-linking reaction in a round box with the front surface facing upwards, pouring 20-50 mL of cellulose modification liquid on the surface of the membrane, adding 1-5 mL of ethanol solution with the ECH content of 5%, performing cross-linking reaction in an oven at 60-80 ℃ for 1-5 h, obtaining a membrane subjected to the second cross-linking reaction after the reaction is finished, and repeatedly washing the membrane subjected to the second cross-linking reaction by using deionized water to obtain the loose nanofiltration membrane with a compact gel layer constructed on the surface of the modified ultrafiltration membrane base membrane.
Further, the stirring temperature in the step 1) is 65 ℃ and the time is 10 hours;
the volume of the Tris buffer solution in the step 2) is 30mL, and the oscillation time is 2 h;
AgNO in step 3)3The concentration of the cellulose modified solution is 2g/L, the volume of the cellulose modified solution obtained in two times is 30mL, the volume of the ethanol solution with the ECH content of 5 percent obtained in two times is 2mL, the temperature of the crosslinking reaction in two times is 70 ℃, and the time is 4 h.
Further, the membrane preparation material in the step 1) is selected from one or more of polyvinylidene fluoride, polyether sulfone, polysulfone and polyimide;
the cellulose in the step 2) and the step 3) is selected from one or more of carboxymethyl cellulose, hydroxyethyl cellulose and ethyl cellulose.
Further, the membrane preparation material in the step 1) is selected from polyvinylidene fluoride, and the molecular weight of the PEG is 600-10000;
the cellulose in the step 2) is selected from carboxymethyl cellulose, the concentration of the cellulose is 1g/L, and the concentration of the dopamine DA is 1g/L
The cellulose in the step 3) is selected from carboxymethyl cellulose, and the concentration of the cellulose is 1 g/L.
Further, the loose nanofiltration membrane for separating the high-flux dye modified by the cellulose gel layer is applied to dye desalination treatment and pollution resistance research.
By adopting the scheme, the invention has the following advantages:
1. the hydrogel is a novel functional material which is composed of hydrophilic polymers and has a three-dimensional network structure, the hydrogel has strong water absorption and water retention capacity, the carboxymethyl cellulose shows the advantages of safety and environmental protection as one of common raw materials for preparing the gel, and secondary pollution is not easy to generate, a gel layer of the three-dimensional network structure is constructed on the surface of a polyvinylidene fluoride ultrafiltration membrane in a layer-by-layer crosslinking mode to form a more stable hydration layer, and the hydration layer is not easy to collapse in the operation process of the nanofiltration membrane, so that excellent hydrophilicity and stain resistance are endowed to the membrane.
2. According to the invention, the gel layer with a compact three-dimensional network structure is constructed on the surface of the polyvinylidene fluoride ultrafiltration membrane, so that the separation of the membrane from the dye and the salt is realized, and the nanofiltration membrane has high permeability and anti-pollution property, has high interception rate on the dye, has high permeability on the salt, has high permeation flux, and is simple to operate and easy to control.
3. The method comprises the steps of firstly utilizing dopamine DA as a functional platform, introducing carboxymethyl cellulose on the surface of a polyvinylidene fluoride ultrafiltration membrane through the codeposition action of DA and carboxymethyl cellulose to obtain a modified polyvinylidene fluoride ultrafiltration membrane, soaking the modified polyvinylidene fluoride ultrafiltration membrane in an ethanol solution of a cross-linking agent epichlorohydrin ECH for a period of time, then immersing the membrane into a modification solution containing ECH cellulose, constructing a compact three-dimensional network gel layer on the surface of the modified polyvinylidene fluoride ultrafiltration membrane through two cross-linking reactions, and obtaining a loose nanofiltration membrane with excellent comprehensive performance by regulating and controlling the concentration of the carboxymethyl cellulose, wherein the rejection rates of the loose nanofiltration membrane on methyl blue, Congo red and direct black dye solutions are all over 99.50%, the rejection rate of the loose nanofiltration membrane on inorganic salt NaCl is lower than 7.7%, and the rejection rate of the loose nanofiltration membrane on inorganic salt Na is lower than 99.50%2SO4The retention rate is lower than 24%, and meanwhile, the loose nanofiltration membrane maintains higher than 285L/m of Congo red solution in a circulation test2H, good anti-pollution performance, and good application prospect, and improves the flux of the loose nanofiltration membrane and the problem of poor anti-pollution performance.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof.
Drawings
FIG. 1 is an ATR-FTIR spectrum of a loose nanofiltration membrane according to example 5 of the present invention;
figure 2 is an SEM image of a loose nanofiltration membrane according to example 6 of the present invention;
figure 3 is a mechanical property diagram of a loose nanofiltration membrane in example 7 of the present invention;
FIG. 4 is a graph showing the separation performance of the loose nanofiltration membrane on the methyl blue dye in example 8 of the present invention;
FIG. 5 is a graph of the long-term separation performance of the loose nanofiltration membrane on the methyl blue dye in example 8 of the present invention;
FIG. 6 is a graph of the rejection of dye and salt by the loose nanofiltration membrane M-CMC-Ag of the present invention;
FIG. 7 is a graph of the separation performance of the loose nanofiltration membrane M-CMC-Ag of the present invention for different dye concentrations and different salt concentrations;
FIG. 8 is a graph of the long-term separation performance of the loose nanofiltration membrane M-CMC-Ag of the present invention on dyes.
Detailed Description
The present invention will now be described in detail with reference to the drawings and examples, which are not intended to limit the invention in any way, except as specifically stated, reagents, methods and apparatus are conventional in the art.
Example 1: a preparation method of a loose nanofiltration membrane for separating high-flux dye modified by a cellulose gel layer.
The method comprises the following specific steps:
1) preparing an ultrafiltration membrane base membrane: sequentially adding dried polyvinylidene fluoride (PVDF), PEG, LiCl and NMP into a three-neck flask, mechanically stirring for 10 hours at 65 ℃ to obtain a uniform membrane casting solution, standing for defoaming, scraping the uniform membrane casting solution on a glass plate by using a membrane scraping machine, soaking the glass plate in a solidification solution, and preparing a PVDF membrane (M-Pure), namely an ultrafiltration membrane base membrane, by an NIPS (nickel-phosphorous sulfide) phase inversion method;
2) co-depositing dopamine and cellulose to modify an ultrafiltration membrane base membrane: soaking the PVDF membrane obtained in the step 1) in 30mL of Tris buffer solution containing 1g/L of carboxymethyl cellulose (CMC) and 1g/L of Dopamine (DA), placing the Tris buffer solution in a shaking table at a constant speed, shaking for 2h, carrying out codeposition coating modification, and after the reaction is finished, washing the membrane by using ethanol solution containing Epoxy Chloropropane (ECH) to obtain a modified PVDF membrane for later use;
3) preparation of a loose nanofiltration membrane:
preparing a CMC modified liquid: preparing CMC aqueous solution from carboxymethyl cellulose with the concentration of 1 g/L;
fixing the modified PVDF membrane in the step 2) in a round box with the front surface facing upwards, pouring 30mL of CMC modified solution on the surface of the modified PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in an oven at 70 ℃ for 4h, obtaining a first crosslinked PVDF membrane after the reaction is finished, then fixing the first crosslinked PVDF membrane in the round box with the front surface facing upwards, pouring 30mL of CMC modified solution on the surface of the first crosslinked PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in the oven at 70 ℃ for 4h, and repeatedly washing the membrane with deionized water after the second crosslinking reaction is finished to obtain the loose nanofiltration membrane (M-CMC) with a compact gel layer constructed on the surface of the modified PVDF membrane.
Example 2: a preparation method of a loose nanofiltration membrane for separating high-flux dye modified by a cellulose gel layer.
The method comprises the following specific steps:
1) preparing an ultrafiltration membrane base membrane: sequentially adding dried polyvinylidene fluoride (PVDF), PEG, LiCl and NMP into a three-neck flask, mechanically stirring for 10 hours at 65 ℃ to obtain a uniform membrane casting solution, standing for defoaming, scraping the uniform membrane casting solution on a glass plate by using a membrane scraping machine, soaking the glass plate in a solidification solution, and preparing a PVDF membrane (M-Pure), namely an ultrafiltration membrane base membrane, by an NIPS (nickel-phosphorous sulfide) phase inversion method;
2) co-depositing dopamine and cellulose to modify an ultrafiltration membrane base membrane: soaking the PVDF membrane obtained in the step 1) in 30mL of Tris buffer solution containing 1g/L of carboxymethyl cellulose (CMC) and 1g/L of Dopamine (DA), placing the Tris buffer solution in a shaking table at a constant speed, shaking for 2h, carrying out codeposition coating modification, and after the reaction is finished, washing the membrane by using ethanol solution containing Epoxy Chloropropane (ECH) to obtain a modified PVDF membrane for later use;
3) preparation of a loose nanofiltration membrane:
preparing a CMC modified liquid: preparing CMC aqueous solution from 1g/L carboxymethyl cellulose, and adding 2g/L AgNO3And NaBH4The Ag NPs particles generated by reduction can be loaded in a CMC cross-linked network structure to enhance the mechanical property of the membrane, so that the CMC modified liquid is prepared, and the NaBH is4With AgNO3In a ratio of 3: 1;
and then fixing the modified PVDF membrane in the step 2) in a round box with the right side facing upwards, pouring 30mL of CMC modified solution on the surface of the modified PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in an oven at 70 ℃ for 4h, obtaining a first crosslinked PVDF membrane after the reaction is finished, then fixing the first crosslinked PVDF membrane in the round box with the right side facing upwards, pouring 30mL of CMC modified solution on the surface of the first crosslinked PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in the oven at 70 ℃ for 4h, and repeatedly washing the membrane with deionized water after the second crosslinking reaction is finished to obtain the loose nanofiltration membrane (M-CMC-Ag) with a compact gel layer constructed on the surface of the modified PVDF membrane.
Example 3: a preparation method of a loose nanofiltration membrane for separating high-flux dye modified by a cellulose gel layer.
The method comprises the following specific steps:
1) preparing an ultrafiltration membrane base membrane: sequentially adding dried polyvinylidene fluoride (PVDF), PEG, LiCl and NMP into a three-neck flask, mechanically stirring for 10 hours at 65 ℃ to obtain a uniform membrane casting solution, standing for defoaming, scraping the uniform membrane casting solution on a glass plate by using a membrane scraping machine, soaking the glass plate in a solidification solution, and preparing a PVDF membrane (M-Pure), namely an ultrafiltration membrane base membrane, by an NIPS (nickel-phosphorous sulfide) phase inversion method;
2) co-depositing dopamine and cellulose to modify an ultrafiltration membrane base membrane: soaking the PVDF membrane obtained in the step 1) in 30mL of Tris buffer solution containing 1g/L of carboxymethyl cellulose (CMC) and 1g/L of Dopamine (DA), placing the Tris buffer solution in a shaking table at a constant speed, shaking for 2h, carrying out codeposition coating modification, and after the reaction is finished, washing the membrane by using ethanol solution containing Epoxy Chloropropane (ECH) to obtain a modified PVDF membrane for later use;
3) preparation of a loose nanofiltration membrane:
preparing a CMC modified liquid: preparing CMC aqueous solution from 5g/L carboxymethyl cellulose, and adding 2g/L AgNO3And NaBH4The Ag NPs particles generated by reduction can be loaded in a CMC cross-linked network structure to enhance the mechanical property of the membrane, so that the CMC modified liquid is prepared, and the NaBH is4With AgNO3In a ratio of 3: 1;
and then fixing the modified PVDF membrane in the step 2) in a round box with the right side facing upwards, pouring 30mL of CMC modified solution on the surface of the modified PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in an oven at 70 ℃ for 4h, obtaining a first crosslinked PVDF membrane after the reaction is finished, then fixing the first crosslinked PVDF membrane in the round box with the right side facing upwards, pouring 30mL of CMC modified solution on the surface of the first crosslinked PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in the oven at 70 ℃ for 4h, and repeatedly washing the membrane with deionized water after the second crosslinking reaction is finished to obtain the loose nanofiltration membrane (M-CMC5-Ag) with a compact gel layer constructed on the surface of the modified PVDF membrane.
Example 4: a preparation method of a loose nanofiltration membrane for separating high-flux dye modified by a cellulose gel layer.
The method comprises the following specific steps:
1) preparing an ultrafiltration membrane base membrane: sequentially adding dried polyvinylidene fluoride (PVDF), PEG, LiCl and NMP into a three-neck flask, mechanically stirring for 10 hours at 65 ℃ to obtain a uniform membrane casting solution, standing for defoaming, scraping the uniform membrane casting solution on a glass plate by using a membrane scraping machine, soaking the glass plate in a solidification solution, and preparing a PVDF membrane (M-Pure), namely an ultrafiltration membrane base membrane, by an NIPS (nickel-phosphorous sulfide) phase inversion method;
2) co-depositing dopamine and cellulose to modify an ultrafiltration membrane base membrane: soaking the PVDF membrane obtained in the step 1) in 30mL of Tris buffer solution containing 1g/L of carboxymethyl cellulose (CMC) and 1g/L of Dopamine (DA), placing the Tris buffer solution in a shaking table at a constant speed, shaking for 2h, carrying out codeposition coating modification, and after the reaction is finished, washing the membrane by using ethanol solution containing Epoxy Chloropropane (ECH) to obtain a modified PVDF membrane for later use;
3) preparation of a loose nanofiltration membrane:
preparing a CMC modified liquid: preparing CMC aqueous solution from 10g/L carboxymethyl cellulose, and adding 2g/L AgNO3And NaBH4The Ag NPs particles generated by reduction can be loaded in a CMC cross-linked network structure to enhance the mechanical property of the membrane, so that the CMC modified liquid is prepared, and the NaBH is4With AgNO3In a ratio of 3: 1;
and then fixing the modified PVDF membrane in the step 2) in a round box with the right side facing upwards, pouring 30mL of CMC modified solution on the surface of the modified PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in an oven at 70 ℃ for 4h, obtaining a first crosslinked PVDF membrane after the reaction is finished, then fixing the first crosslinked PVDF membrane in the round box with the right side facing upwards, pouring 30mL of CMC modified solution on the surface of the first crosslinked PVDF membrane, adding 2mL of ethanol solution with the ECH content of 5%, performing crosslinking reaction in the oven at 70 ℃ for 4h, and repeatedly washing the membrane with deionized water after the second crosslinking reaction is finished to obtain the loose nanofiltration membrane (M-CMC10-Ag) with a compact gel layer constructed on the surface of the modified PVDF membrane.
Example 5: infrared spectroscopy detection
1. Experimental Material
The base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-CMC5-Ag and the loose nanofiltration membrane M-CMC10-Ag were prepared under the conditions of examples 1-4.
2. Experimental methods
Respectively carrying out freeze-drying on a base membrane M-Pure, a loose nanofiltration membrane M-CMC-Ag, a loose nanofiltration membrane M-CMC5-Ag and a loose nanofiltration membrane M-CMC10-Ag by using a freeze-drying machine to constant weight, and respectively representing the chemical compositions of the base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-5-Ag and the loose nanofiltration membrane M-CMC10-Ag by using Fourier total reflection infrared spectroscopy (FTIR, Nicolet iS50, GER).
3. Results of the experiment
From FIG. 1, 1400cm in the infrared spectrum-1、1170cm-1、838cm-1The characteristic peak at (A) is a characteristic peak typical of PVDF. Compared with the base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-CMC5-Ag and the loose nanofiltration membrane M-CMC10-Ag are at 1670cm-1A new characteristic peak appears at each site, which is attributed to the-C ═ O peak contained in CMC. Further, it was found that the film M-CMC-Ag has the highest-C ═ O peak intensity, and the-C ═ O peak tends to decrease with the increase in the amount of CMC added, and the viscosity of the modifying solution increases with the increase in the amount of CMC, resulting in deterioration of the crosslinking effect. The successful construction of the CMC gel layer on the surface of the PVDF film is evidenced by the appearance of the-C ═ O peak.
Example 6: electron microscope observation of film surface morphology
1. Experimental Material
The base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-CMC5-Ag and the loose nanofiltration membrane M-CMC10-Ag were prepared under the conditions of examples 1-4.
2. Experimental methods
Cutting the freeze-dried base membrane M-Pure, loose nanofiltration membrane M-CMC-Ag, loose nanofiltration membrane M-CMC5-Ag and loose nanofiltration membrane M-CMC10-Ag into 2 multiplied by 4mm2The sample strips are respectively stuck on a sample table with the front surfaces thereof facing upwards by using conductive adhesive, the surface appearance of the membrane is observed by adopting an SEM after gold spraying treatment, and the surface of the membrane is respectively characterized by using a field emission scanning electron microscope (SEM, S-4800).
3. Results of the experiment
As can be seen from FIG. 2, the pores of the base film M-Pure were clearly observed on the surface thereof. The CMC is introduced into the surface of the PVDF membrane to form a gel layer, and the pores on the surface of the membrane are obviously reduced. When the surface modification is further carried out by adding a modification solution containing Ag NP, the existence of the Ag NP is observed from the surface of the loose nanofiltration membrane M-CMC-Ag. The CMC gel layer has a unique three-dimensional network structure which is a good bearing site for inorganic particles. Along with the gradual increase of the addition amount of CMC, the Ag NP fixed on the surface of the loose nanofiltration membrane also increases.
Example 7: mechanical Property test
1. Experimental Material
The base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-CMC5-Ag and the loose nanofiltration membrane M-CMC10-Ag were prepared under the conditions of examples 1-4.
2. Experimental methods
Firstly, carrying out freeze-drying treatment on a base membrane M-Pure, a loose nanofiltration membrane M-CMC-Ag, a loose nanofiltration membrane M-CMC5-Ag and a loose nanofiltration membrane M-CMC 10-Ag. The freeze-dried film was cut into 10mm × 40mm strips, and the thickness of the strips was measured using a thickness gauge. The sample strip is arranged in a clamp, the length of the middle effective area is 20mm, corresponding parameters are input, the stretching speed is set to be 10mm/min, and the mechanical properties of the base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-CMC5-Ag and the loose nanofiltration membrane M-CMC10-Ag are respectively tested by using a precise electronic universal stretcher.
3. Results of the experiment
As can be seen from FIG. 3, the tensile strength of the base film M-Pure was 1.03MPa, and the elongation at break was 66.6%. The tensile strength of the film M-CMC increased to 1.41MPa and the elongation at break decreased to 41.3%. Compared with the membrane M-Pure, the membrane M-CMC becomes brittle and has reduced toughness. When the surface of the membrane M-CMC is further introduced with a modification solution containing Ag NP for surface modification, the tensile strength of the membrane M-CMC-Ag is 1.38MPa, the elongation at break is 56.5 percent, and the membrane M-CMC-Ag can maintain higher tensile strength and larger elongation at break. The main reason is that the three-dimensional network structure of the CMC gel layer is a good bearing site of the Ag NP particles, and the introduction of the Ag NP particles improves the mechanical property of the membrane. As the CMC content further increases, both the tensile strength and the elongation at break of the film decrease. The main reasons are that the binding capacity of a gel layer and a membrane on the surface of the membrane is reduced as the CMC content is increased and the concentration of a modifying solution is increased, the three-dimensional network structure of the gel layer cannot be well constructed, and the mechanical property of the membrane is reduced.
Example 8: water flux test
1. Experimental Material
The base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-CMC5-Ag and the loose nanofiltration membrane M-CMC10-Ag were prepared under the conditions of examples 1-4.
2. Experimental methods
Carrying out flux and dye/salt separation performance tests on the loose nanofiltration membrane modified by the gel layer of the base membrane M-Pure, the loose nanofiltration membrane M-CMC-Ag, the loose nanofiltration membrane M-CMC5-Ag and the loose nanofiltration membrane M-CMC10-Ag by using a cross flow device;
testing of water flux: respectively placing a base membrane M-Pure, a loose nanofiltration membrane M-CMC-Ag, a loose nanofiltration membrane M-CMC5-Ag and a loose nanofiltration membrane M-CMC10-Ag in membrane pools, taking deionized water as a feeding liquid, testing the water flux of the membrane after prepressing for 1h, and marking the water flux as J (L/M)2H.bar), the water flux is calculated from formula (1);
the separation performance of the membranes for different dyes was tested: the concentration of the used dye is 0.1g/L, the operating pressure is set to be 0.1MPa, the flux of the membrane to the dye is tested after pre-pressing for 1h, feeding liquid and filtrate are collected, and the rejection rate R (%) of the membrane to different dyes is calculated according to a formula (2);
test membrane vs dye/salt binary System (Congo Red and NaCl Mixed solution, Congo Red and Na)2SO4Mixed solution) separation performance: the concentrations of the dye and the salt in the feed liquid are respectively 0.1g/L and 1g/L, and the retention rates of the membrane to different dyes and salts are calculated according to a formula (2);
the Congo red dye solution is subjected to a cycle test to characterize the anti-pollution performance of the membrane: the method comprises the steps of firstly carrying out dye separation on a model pollutant of 0.1g/L Congo red solution under the operation pressure of 0.1MPa, changing the dye solution into deionized water after running for 90min, cleaning for 10min under the pressure-free condition, and continuously carrying out separation test on the dye solution, wherein the whole anti-pollution test is divided into three pollution stages and two pure water cleaning stages.
In the formula (1), V is the volume (L) of the penetrating fluid in a certain time, and A is the effective filtering area (m) of the membrane tank2) Δ t is the time (h) to collect the filtrate;
in the formula (2), R is the rejection (%) of the solute; cfThe concentration (g/L) of solute in the stock solution; cpThe concentration of solute in the permeate (g/L).
Measuring the conductivity of inorganic salt solution by using a conductivity meter, and calculating NaCl and Na in penetrating fluid and raw material fluid according to a standard curve2SO4The concentration of solute in the solution; and (3) measuring the absorbance at the maximum absorption wavelength of the dye by using an ultraviolet spectrophotometer, and calculating the concentrations of solutes in different dye solutions in the penetrating fluid and the raw material solution according to a standard curve. And finally, calculating the retention rate of each separation system according to the formula (2).
3. Results of the experiment
Table 1 physical characteristics and separation performance test data of high flux loose nanofiltration membrane
As can be seen from table 1, fig. 3, fig. 4, and fig. 5, the M-CMC-Ag film has better overall performance, because too high CMC content causes too high viscosity of the modification solution, and the binding capacity between the gel and the film is reduced, so that a complete and good gel layer cannot be formed on the surface of the film;
as can be seen from FIG. 6, the flux of M-CMC-Ag film to Congo red and direct black dye solutions was 263.65L/M, respectively2H.bar and 298.00L/m2H.bar, 99.9% and 99.5% retention respectively for NaCl and Na2SO4The retention rates are 7.61% and 23.6 respectively;
as can be seen from fig. 7, the M-CMC-Ag membrane still maintains high flux and high retention of the dye, high permeability to salt when processing different components of the dye/salt mixed system;
as can be seen from FIG. 8, the cycle test result of the M-CMC-Ag membrane on Congo red dye solution shows that the membrane still has higher dye flux after 3 cycles, and the flux is kept stable, thus showing better anti-fouling performance.
Finally, the description is as follows: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the invention as defined by the appended claims. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (8)
1. The loose nanofiltration membrane for separating the high-flux dye modified by the cellulose gel layer is characterized by comprising an ultrafiltration base membrane which is coated and modified by codeposition of dopamine and carboxymethyl cellulose and a gel layer which is of a compact three-dimensional network structure and is constructed on the surface of the modified ultrafiltration base membrane by twice cross-linking reactions of carboxymethyl cellulose under the action of a cross-linking agent, wherein the thickness of the nanofiltration membrane is 110nm, and the pore diameter of the nanofiltration membrane is 1.38 nm.
2. The cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation according to claim 1, wherein the ultrafiltration membrane is one or more of a polyvinylidene fluoride ultrafiltration membrane, a polyethersulfone ultrafiltration membrane, a polysulfone ultrafiltration membrane and a polyimide ultrafiltration membrane.
3. The cellulose gel layer modified high-flux loose nanofiltration membrane for dye separation according to claim 2, wherein the ultrafiltration membrane is a polyvinylidene fluoride ultrafiltration membrane, the thickness of the membrane is 100-400 μm, and the pore diameter of the membrane is 4.24 nm.
4. The preparation method of the cellulose gel layer modified loose nanofiltration membrane for high-flux dye separation according to claim 3, which comprises the following specific steps:
1) preparing an ultrafiltration membrane base membrane: sequentially adding the dried membrane preparation material, PEG, LiCl and NMP into a three-neck flask, stirring for 8-12 h at the temperature of 60-80 ℃ to obtain a uniform membrane casting solution, standing and defoaming, scraping the uniform membrane casting solution on a glass plate by using a membrane scraper, soaking the glass plate in a solidification solution, and preparing an ultrafiltration membrane basement membrane by an NIPS phase inversion method;
2) co-depositing dopamine and cellulose to modify an ultrafiltration membrane base membrane: soaking the ultrafiltration membrane base membrane obtained in the step 1) in 20-50 mL of Tris buffer solution containing 0.5-2 g/L cellulose and 0.5-2 g/L dopamine DA, placing the Tris buffer solution in a shaking table at a constant speed, shaking for 1-4 h, carrying out codeposition coating modification, and after the reaction is finished, washing the membrane by using ethanol solution containing epichlorohydrin ECH to obtain a modified ultrafiltration membrane base membrane for later use;
3) preparation of a loose nanofiltration membrane:
preparing a cellulose modified solution: taking 0.5g/L-10g/L cellulose water solution, adding AgNO with the molar ratio of 3:13And NaBH4Obtaining cellulose modified liquid;
fixing the modified ultrafiltration membrane base membrane in the step 2) in a round box with the front side facing upwards, pouring 20-50 mL of cellulose modification liquid on the surface of the modified ultrafiltration membrane base membrane, adding 1-5 mL of ethanol solution with the ECH content of 5%, and performing crosslinking reaction in an oven at 60-80 ℃ for 1-5 h to obtain a membrane for the first crosslinking reaction after the reaction is finished;
and (2) fixing the membrane subjected to the first cross-linking reaction in a round box with the front surface facing upwards, pouring 20-50 mL of cellulose modification liquid on the surface of the membrane, adding 1-5 mL of ethanol solution with the ECH content of 5%, performing cross-linking reaction in an oven at 60-80 ℃ for 1-5 h, obtaining a membrane subjected to the second cross-linking reaction after the reaction is finished, and repeatedly washing the membrane subjected to the second cross-linking reaction by using deionized water to obtain the loose nanofiltration membrane with a compact gel layer constructed on the surface of the modified ultrafiltration membrane base membrane.
5. The method for preparing the cellulose gel layer modified high-flux dye separation porous nanofiltration membrane according to claim 4, wherein the stirring temperature in the step 1) is 65 ℃ and the stirring time is 10 hours;
the volume of the Tris buffer solution in the step 2) is 30mL, and the oscillation time is 2 h;
AgNO in step 3)3The concentration of the cellulose modified solution is 2g/L, the volume of the cellulose modified solution obtained in two times is 30mL, the volume of the ethanol solution with the ECH content of 5 percent obtained in two times is 2mL, the temperature of the crosslinking reaction in two times is 70 ℃, and the time is 4 h.
6. The preparation method of the cellulose gel layer modified high-flux loose nanofiltration membrane for dye separation according to claim 4, wherein the membrane preparation material in the step 1) is selected from one or more of polyvinylidene fluoride, polyethersulfone, polysulfone and polyimide;
the cellulose in the step 2) and the step 3) is selected from one or more of carboxymethyl cellulose, hydroxyethyl cellulose and ethyl cellulose.
7. The method for preparing the cellulose gel layer modified high-flux dye separation porous nanofiltration membrane according to claim 6, wherein the membrane preparation material in the step 1) is selected from polyvinylidene fluoride, and the molecular weight of the PEG is 600-10000;
the cellulose in the step 2) is selected from carboxymethyl cellulose, the concentration of the cellulose is 1g/L, and the concentration of the dopamine DA is 1g/L
The cellulose in the step 3) is selected from carboxymethyl cellulose, and the concentration of the cellulose is 1 g/L.
8. The use of the cellulose gel layer modified high-flux dye separation loose nanofiltration membrane according to any one of claims 1 to 4 in dye desalination treatment and anti-pollution research.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114288872A (en) * | 2022-01-12 | 2022-04-08 | 广东省科学院生态环境与土壤研究所 | High-stability and high-flux polydopamine nanoparticle modified membrane and preparation method and application thereof |
| CN114534527A (en) * | 2022-04-18 | 2022-05-27 | 重庆文理学院 | Membrane filtration assembly |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0347755A2 (en) * | 1988-06-21 | 1989-12-27 | Millipore Corporation | Charge-modified hydrophobic membrane materials and method for making the same |
| CN106731883A (en) * | 2016-11-10 | 2017-05-31 | 北京林业大学 | A kind of poly-dopamine nano lignocellulose Kynoar composite hyperfiltration membrane and preparation method thereof |
| CN107551832A (en) * | 2017-09-21 | 2018-01-09 | 福建农林大学 | A kind of preparation method of the cross-linking modified NF membrane of regenerated cellulose base |
| CN110743391A (en) * | 2019-10-15 | 2020-02-04 | 周丹丹 | Preparation method of functional polyvinylidene fluoride membrane |
| CN113230908A (en) * | 2021-05-18 | 2021-08-10 | 四川大学 | Cellulose acetate filtering membrane and preparation method thereof |
-
2021
- 2021-10-12 CN CN202111186140.9A patent/CN113797763B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0347755A2 (en) * | 1988-06-21 | 1989-12-27 | Millipore Corporation | Charge-modified hydrophobic membrane materials and method for making the same |
| CN106731883A (en) * | 2016-11-10 | 2017-05-31 | 北京林业大学 | A kind of poly-dopamine nano lignocellulose Kynoar composite hyperfiltration membrane and preparation method thereof |
| CN107551832A (en) * | 2017-09-21 | 2018-01-09 | 福建农林大学 | A kind of preparation method of the cross-linking modified NF membrane of regenerated cellulose base |
| CN110743391A (en) * | 2019-10-15 | 2020-02-04 | 周丹丹 | Preparation method of functional polyvinylidene fluoride membrane |
| CN113230908A (en) * | 2021-05-18 | 2021-08-10 | 四川大学 | Cellulose acetate filtering membrane and preparation method thereof |
Non-Patent Citations (3)
| Title |
|---|
| CHAO ZHOU等: "Fabrication and characterization of novel composite nanofiltration, membranes based on zwitterionic O-carboxymethyl chitosan", 《DESALINATION》 * |
| 汪祺等: "仿蜘蛛网结构油水分离膜的制备和性能探索", 《膜科学与技术》 * |
| 苗晶: "基于壳聚糖硫酸酯、羧甲基壳聚糖及羧甲基纤维素钠复合纳滤膜的研究", 《中国优秀博硕士学位论文全文数据库(博士) 工程科技Ⅰ辑》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114288872A (en) * | 2022-01-12 | 2022-04-08 | 广东省科学院生态环境与土壤研究所 | High-stability and high-flux polydopamine nanoparticle modified membrane and preparation method and application thereof |
| CN114534527A (en) * | 2022-04-18 | 2022-05-27 | 重庆文理学院 | Membrane filtration assembly |
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