CN113413769A - Preparation method of nanofiltration membrane with high permeability and high selectivity - Google Patents

Preparation method of nanofiltration membrane with high permeability and high selectivity Download PDF

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CN113413769A
CN113413769A CN202110226727.1A CN202110226727A CN113413769A CN 113413769 A CN113413769 A CN 113413769A CN 202110226727 A CN202110226727 A CN 202110226727A CN 113413769 A CN113413769 A CN 113413769A
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solution
membrane
nanofiltration
high selectivity
phase solution
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CN113413769B (en
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赵长伟
唐文晶
赫东煜
李研
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China Agricultural University
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China Agricultural University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • B01D69/125—In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/027—Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/10—Testing of membranes or membrane apparatus; Detecting or repairing leaks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0081—After-treatment of organic or inorganic membranes
    • B01D67/0095—Drying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/12—Specific ratios of components used
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination
    • Y02A20/131—Reverse-osmosis

Abstract

The invention relates to a preparation method of a nanofiltration membrane with high permeability and high selectivity, which comprises the following steps: preprocessing a nanofiltration base membrane; preparing aminated graphene into an aqueous solution, and then carrying out ultrasonic treatment to obtain an aminated graphene solution; preparing acid solution with potassium dihydrogen phosphate and phosphoric acid; preparing piperazine solution from piperazine, and mixing the piperazine solution with triethylamine and aminated graphene solution to prepare aqueous phase solution; dropwise adding the prepared acidic solution into the aqueous phase solution, and adjusting the pH value of the aqueous phase solution; mixing trimesoyl chloride and a normal hexane solvent to prepare an organic phase solution; and (3) putting the pretreated nanofiltration base membrane into an aqueous phase solution, taking out and drying the nanofiltration base membrane, putting the dried nanofiltration base membrane into an organic phase solution for interfacial polymerization reaction, taking out and drying the nanofiltration base membrane again to obtain the nanofiltration membrane with high permeability and high selectivity. According to the method, the aminated graphene subjected to ultrasonic dispersion is introduced, so that the nanofiltration membrane with high water permeability and high selectivity is obtained.

Description

Preparation method of nanofiltration membrane with high permeability and high selectivity
Technical Field
The invention relates to the technical field of separation membrane preparation, in particular to a preparation method of a nanofiltration membrane with high permeability and high selectivity.
Background
The nanofiltration membrane technology is a novel technology for separating organic matters and inorganic salts with molecular weight of 200-1000Da through steric exclusion and the southwest effect. To date, many attempts have been made to adjust the physicochemical properties of the nanofiltration membrane surface, such as pore size, surface charge, wettability, and roughness, in order to improve the filtration performance of the nanofiltration membrane. However, polymer-based membranes have inherent limitations of selectivity-permeability trade-offs, limited by the polymer matrix chain stiffness and inter-chain spacing.
Graphene is a carbon material widely used by people due to the characteristics of an ultra-large specific surface, good mechanical strength, ultra-high conductivity, good electrochemical stability, easy synthesis and the like, but the graphene has poor dispersibility in polymers. However, the aminated graphene introduces amino groups on the surface of graphene, so that the hydrophilicity and polarity of graphene are improved, and the graphene is easily dispersed in polyamide. Meanwhile, the amino group has higher reactivity, so that the aminated graphene can react with most compounds. Therefore, the aminated graphene has excellent application prospect in preparation of composite materials.
Disclosure of Invention
Based on the above, the invention aims to provide a preparation method of a nanofiltration membrane with high permeability and high selectivity. According to the preparation method, an interfacial polymerization method is adopted on a nanofiltration base membrane, aminated graphene subjected to ultrasonic dispersion is introduced into a polyamide layer, the dispersibility of the aminated graphene in a water-phase solution is improved, and the nanofiltration membrane with high permeability and high selectivity is prepared.
Therefore, the invention provides a preparation method of a nanofiltration membrane with high permeability and high selectivity, which comprises the following steps:
(1) preprocessing a nanofiltration base membrane;
(2) preparing aminated graphene into an aqueous solution, and then carrying out ultrasonic treatment to obtain an aminated graphene solution;
(3) preparing acid solution with potassium dihydrogen phosphate and phosphoric acid;
(4) preparing piperazine solution from piperazine, and mixing the piperazine solution with aminated graphene solution and triethylamine to prepare aqueous phase solution;
(5) dropwise adding the prepared acidic solution into the aqueous phase solution, and adjusting the pH value of the aqueous phase solution;
(6) mixing trimesoyl chloride and a normal hexane solvent to prepare an organic phase solution;
(7) and (3) putting the pretreated nanofiltration base membrane into an aqueous phase solution, taking out and drying the nanofiltration base membrane, putting the dried nanofiltration base membrane into an organic phase solution for interfacial polymerization reaction, taking out and drying the nanofiltration base membrane again to obtain the nanofiltration membrane with high permeability and high selectivity.
The preparation method of the nanofiltration membrane with high permeability and high selectivity, disclosed by the invention, comprises the following steps of (1) preferably preparing the nanofiltration base membrane from polyether sulfone, more preferably preparing the nanofiltration base membrane from polyether sulfone, wherein the membrane cut-off molecular weight of the nanofiltration base membrane is more than 50KDa and less than 150KDa, and the pretreatment comprises the following steps: and (3) soaking the nanofiltration base membrane into deionized water at 15-30 ℃ for 48-98h, and replacing the deionized water every 6-12 h.
The preparation method of the nanofiltration membrane with high permeability and high selectivity, disclosed by the invention, preferably comprises the following ultrasonic treatment conditions: the time is 30-120min, the temperature is 20-40 ℃, and the ultrasonic frequency is 20-40 KHz.
According to the preparation method of the nanofiltration membrane with high permeability and high selectivity, the concentration of the aminated graphene in the aqueous phase solution is preferably 100ppm to 500 ppm.
According to the preparation method of the nanofiltration membrane with high permeability and high selectivity, the concentrations of potassium dihydrogen phosphate and phosphoric acid in the acid solution are preferably 0.5-1 wt% and 5-10 wt%, respectively.
According to the preparation method of the nanofiltration membrane with high permeability and high selectivity, the mass percent of piperazine in the piperazine solution is preferably 0.1-0.5 wt% in the step (4); the mass ratio of the aminated graphene solution to the piperazine solution is 1: 1-9; the mass percent of triethylamine in the aqueous phase solution is 0.05-0.25 wt%.
According to the preparation method of the nanofiltration membrane with high permeability and high selectivity, the pH value of the aqueous phase solution is preferably adjusted to 8-12 in the step (5).
According to the preparation method of the nanofiltration membrane with high permeability and high selectivity, the mass percentage of trimesoyl chloride in the organic phase solution is preferably 0.1-0.5 wt%.
The preparation method of the nanofiltration membrane with high permeability and high selectivity, disclosed by the invention, has the advantages that the retention time of the nanofiltration base membrane in an aqueous phase solution is preferably 2-8min, and the drying is rubber roll drying.
The preparation method of the nanofiltration membrane with high permeability and high selectivity, disclosed by the invention, preferably comprises the following conditions of interfacial polymerization reaction: the time is 1-10min, the temperature is 23-27 ℃, and the conditions of secondary drying are as follows: the temperature is 50-90 deg.C, and the time is 1-6 min.
The preparation method of the nanofiltration membrane with high permeability and high selectivity comprises the following specific steps (the preparation method is carried out at room temperature):
s1, soaking polyether sulfone (PES) with the size of 6cm multiplied by 6cm (the membrane cut-off molecular weight is 100KDa) in deionized water for pretreatment, wherein the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
S2, putting 500mg of aminated graphene into a beaker, and then adding 500ml of deionized water to prepare an aqueous solution;
and S3, placing the aqueous solution prepared in the step S2 in an ultrasonic instrument, and treating the aqueous solution under the condition that the ultrasonic frequency is 40KHz for 30min to obtain a uniform aminated graphene solution.
S4, preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and then adding 0.05 wt% of triethylamine to prepare an aqueous phase solution.
S5, adding a certain amount of prepared acid solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
S6, mixing a certain amount of trimesoyl chloride with a normal hexane solvent to prepare an organic phase solution with the mass percent of the trimesoyl chloride of 0.2%.
S7, immersing the pretreated PES membrane into the aqueous phase solution, and taking out after 4 min; drying the residual moisture on the surface of the film by using a rubber roller, and then putting the film into an organic phase solution for interfacial polymerization; and taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
And S8, taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for subsequent measurement.
The invention has the following beneficial effects:
(1) according to the method, the aminated graphene subjected to ultrasonic dispersion is introduced to obtain the aqueous phase solution with excellent dispersion performance, so that the aminated graphene reacts more uniformly during interfacial polymerization, and the agglomeration phenomenon cannot occur.
(2) According to the invention, triethylamine, piperazine solution and acid solution are added while the aminated graphene subjected to ultrasonic dispersion is added into the water phase solution, so that the acylation reaction speed is accelerated, and the added aminated graphene can participate in the reaction more uniformly; therefore, the nanofiltration membrane prepared by the method has high water permeability and high selectivity.
(3) Phosphoric acid is adopted in the acidic solution, and compared with sulfuric acid, phosphoric acid belongs to weak acid, so that the pH value of the solution is easier to regulate and control.
Detailed Description
The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.
Example 1
The preparation of the nanofiltration membrane with high permeability and high selectivity is carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 2min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 54.6Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 99.2%, and the retention rate of the NaCl aqueous solution was 11.2%.
Example 2
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1:1, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%. .
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 2min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 51.9Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.4%, and the retention rate of the NaCl aqueous solution was 11.0%.
Example 3
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 9, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 2min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 49.2Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.1%, and the retention rate of the NaCl aqueous solution was 11.7%.
Example 4
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.3 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.15 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 2min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 49.9Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution is 97.4 percent, and the retention rate of the NaCl aqueous solution is 12.1 percent。
Example 5
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.5 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.25 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 2min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 48.9Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.6%, and the retention rate of the NaCl aqueous solution was 11.8%.
Example 6
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 0.5g of monopotassium phosphate, 5g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.1 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. Test result tableObviously, the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 50.2Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.0% and that of the NaCl aqueous solution was 9.8%.
Example 7
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1:1, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 0.5g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.5 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 2min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4In the form of an aqueous solutionAnd the performance of the nanofiltration membrane with high permeability and high selectivity prepared by testing the NaCl aqueous solution with the concentration of 2000 ppm. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 49.7Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.8%, and the retention rate of the NaCl aqueous solution was 12.0%.
Example 8
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 5g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 2 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) Taking out the dried nanofiltration membrane with high permeability and high selectivity, sealing in a water environment,for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 49.1Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.2%, and the retention rate of the NaCl aqueous solution was 10.2%.
Example 9
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 5 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 2min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 47.9Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.4%, and the retention rate of the NaCl aqueous solution was 12.3%.
Example 10
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 1min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 48.8Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 98.7%, and the retention rate of the NaCl aqueous solution was 10.3%.
Example 11
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. Taking out after 5min, putting into a constant temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 47.9Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 97.4%, and the retention rate of the NaCl aqueous solution was 11.1%.
Example 12
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 8-9.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 44.1Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 97.8%, and the retention rate of the NaCl aqueous solution was 11.8%.
Example 13
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 11-12.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 47.6Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 97.5%, and the retention rate of the NaCl aqueous solution was 9.7%.
Example 14
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 50 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 46.6Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 96.0%, and the retention rate of the NaCl aqueous solution was 12.8%.
Example 15
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 90 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 48.2Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 96.8%, and the retention rate of the NaCl aqueous solution was 10.3%.
Example 16
The nanofiltration membrane with high permeability and high selectivity is prepared, and the following steps without temperature indication are all carried out at room temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic frequency is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%.
(4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(5) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(6) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 10 min.
(7) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 45.2Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 96.4%, and the retention rate of the NaCl aqueous solution was 12.6%.
Comparative example 1
Nanofiltration membranes were prepared, all following steps at room temperature, not indicated for temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) Preparing an aqueous phase solution: 51mg of aminated graphene, 0.2g of piperazine, 0.25g of sodium dodecyl sulfate and 0.1g of triethylamine are respectively weighed and added into 200ml of deionized water to be completely dissolved, and the pH value is adjusted to 9-10 by using sulfuric acid.
(3) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(4) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(5) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 39.0Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 97.5%, and the retention rate of the NaCl aqueous solution was 13.8%.
Comparative example 2
Nanofiltration membranes were prepared, all following steps at room temperature, not indicated for temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 100KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic power is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3 to prepare aqueous phase solution.
(4) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(5) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(6) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 38.9Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 96.5%, and the retention rate of the NaCl aqueous solution was 11.3%.
Comparative example 3
Nanofiltration membranes were prepared, all following steps at room temperature, not indicated for temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the cut-off molecular weight of 50000Da is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic power is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%. (4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(4) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(5) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(6) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 25.2Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 97.6%, and the retention rate of the NaCl aqueous solution was 13.8%.
Comparative example 4
Nanofiltration membranes were prepared, all following steps at room temperature, not indicated for temperature.
(1) The polyether sulfone (PES) membrane with the size of 6cm multiplied by 6cm and the molecular weight cutoff of 150KDa is soaked in deionized water for pretreatment, the soaking time is 48 hours, and the deionized water needs to be replaced every 12 hours.
(2) And putting 500mg of aminated graphene into a beaker, adding 500ml of deionized water to prepare an aqueous solution, and then carrying out ultrasonic treatment for 30min under the condition that the ultrasonic power is 40KHz to obtain an aminated graphene solution.
(3) Preparing a certain amount of piperazine into 0.1 wt% piperazine solution, and mixing the aminated graphene solution and the piperazine solution according to the weight ratio of 1: 3, and adding triethylamine to prepare an aqueous phase solution, wherein the triethylamine content in the aqueous phase solution is 0.05 wt%. (4) An acidic solution was prepared with 1g of monopotassium phosphate, 10g of phosphoric acid and 100g of deionized water. Adding a certain amount of the prepared acidic solution into the aqueous phase solution to ensure that the pH value of the aqueous phase solution is in a range of 9-10.
(4) Taking trimesoyl chloride and a normal hexane solvent to mix and prepare an organic phase solution with 0.2 percent of trimesoyl chloride by mass percent.
(5) And (3) immersing the pretreated PES membrane into the prepared water phase solution, and taking out after 4 min. And drying the residual moisture on the surface of the membrane by using a rubber roller, and then putting the membrane into the organic phase solution for interfacial polymerization. And taking out after 2min, putting into a constant-temperature drying oven at 80 ℃, and obtaining the nanofiltration membrane with high permeability and high selectivity after 1 min.
(6) And taking out the dried nanofiltration membrane with high permeability and high selectivity, and sealing the nanofiltration membrane in a water environment for measurement. Under 0.2MPa, pure water and 2000ppm of Na are respectively used2SO4The water solution and the NaCl water solution of 2000ppm test the performance of the prepared nanofiltration membrane with high permeability and high selectivity. The test result shows that the pure water permeability of the nanofiltration membrane with high permeability and high selectivity is 39.2Lm-2h-1bar-1，Na2SO4The retention rate of the aqueous solution was 93.6% and that of the NaCl aqueous solution was 11.8%.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.

Claims (10)

1. A preparation method of a nanofiltration membrane with high permeability and high selectivity is characterized by comprising the following steps:
(1) preprocessing a nanofiltration base membrane;
(2) preparing aminated graphene into an aqueous solution, and then carrying out ultrasonic treatment to obtain an aminated graphene solution;
(3) preparing acid solution with potassium dihydrogen phosphate and phosphoric acid;
(4) preparing piperazine solution from piperazine, and mixing the piperazine solution with aminated graphene solution and triethylamine to prepare aqueous phase solution;
(5) dropwise adding the prepared acidic solution into the aqueous phase solution, and adjusting the pH value of the aqueous phase solution;
(6) mixing trimesoyl chloride and a normal hexane solvent to prepare an organic phase solution;
(7) and (3) putting the pretreated nanofiltration base membrane into an aqueous phase solution, taking out and drying the nanofiltration base membrane, putting the dried nanofiltration base membrane into an organic phase solution for interfacial polymerization reaction, taking out and drying the nanofiltration base membrane again to obtain the nanofiltration membrane with high permeability and high selectivity.
2. The preparation method of a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein the nanofiltration base membrane is made of polyethersulfone, preferably, the nanofiltration base membrane has a membrane cut-off molecular weight of more than 50KDa and less than 150KDa, and the pretreatment comprises: and (3) soaking the nanofiltration base membrane into deionized water at 15-30 ℃ for 48-98h, and replacing the deionized water every 6-12 h.
3. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein the ultrasonic treatment conditions comprise: the time is 30-120min, the temperature is 20-40 ℃, and the ultrasonic frequency is 20-40 KHz.
4. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein the concentration of the aminated graphene in the aqueous solution is 100ppm to 500 ppm.
5. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein the concentrations of potassium dihydrogen phosphate and phosphoric acid in the acidic solution are 0.5-1 wt% and 5-10 wt%, respectively.
6. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein in the step (4), the mass percent of piperazine in the piperazine solution is 0.1-0.5 wt%; the mass ratio of the aminated graphene solution to the piperazine solution is 1: 1-9; the mass percent of triethylamine in the aqueous phase solution is 0.05-0.25 wt%.
7. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein in the step (5), the pH value of the aqueous phase solution is adjusted to 8-12.
8. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein the mass percentage of trimesoyl chloride in the organic phase solution is 0.1-0.5 wt%.
9. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein the retention time of the nanofiltration base membrane in the aqueous solution is 2-8min, and the drying is rubber roll drying.
10. The method for preparing a nanofiltration membrane with high permeability and high selectivity according to claim 1, wherein the interfacial polymerization reaction conditions are as follows: the time is 1-10min, the temperature is 23-27 ℃, and the conditions of secondary drying are as follows: the temperature is 50-90 deg.C, and the time is 1-6 min.
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