CN111450714A - Method for preparing composite nanofiltration membrane by using multi-element buffer system - Google Patents
Method for preparing composite nanofiltration membrane by using multi-element buffer system Download PDFInfo
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- CN111450714A CN111450714A CN202010303658.5A CN202010303658A CN111450714A CN 111450714 A CN111450714 A CN 111450714A CN 202010303658 A CN202010303658 A CN 202010303658A CN 111450714 A CN111450714 A CN 111450714A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/56—Polyamides, e.g. polyester-amides
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- 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
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- 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
- B01D67/0002—Organic membrane manufacture
- B01D67/0006—Organic membrane manufacture by chemical reactions
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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
- B01D69/02—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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- 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
Abstract
The invention belongs to the technical field of nanofiltration composite membranes, and particularly relates to a method for preparing a composite nanofiltration membrane by using a multi-element buffer system. The invention discloses a water phase buffer formula, wherein polyamine monomers participating in interfacial polymerization reaction are brought into a buffer system, organic weak acid, quaternary ammonium salt or/and quaternary ammonium base are mixed according to a certain proportion to form a multi-component buffer system, the multi-component buffer system is coated on the surface of a porous support membrane, after drying in the shade, aromatic polyatomic acyl chloride organic phase solution is coated, and finally a nanofiltration composite membrane can be prepared through heat treatment at a certain temperature. The multi-element buffer aqueous phase solution can be repeatedly used after being prepared once, and the performance of the nanofiltration membrane prepared under the same condition is stable. The method effectively solves the problem that the amine monomer is easy to oxidize and lose the reactivity, solves the problem of the fluctuation of the performance of the membrane product, ensures the continuous production of the nanofiltration composite membrane, reduces the consumption of a water phase, and simultaneously improves the stability of the performance of products, thereby greatly reducing the production cost of the nanofiltration membrane.
Description
Technical Field
The invention belongs to the technical field of nanofiltration composite membranes, and relates to a method for preparing a nanofiltration membrane by using a polyamine monomer-participated co-constructed multielement buffer system
Background
The nanofiltration membrane is a selective pressure driven semipermeable membrane allowing low molecular weight solutes or low-valent ions to permeate, and is applied to the reclamation of high-salinity and high-pollution wastewater such as dye, electroplating and the like and the treatment of municipal drinking water. The development in the international market has been very rapid in recent years by virtue of its unique separation characteristics, and the attention is paid to the preparation method and the application process thereof. The nanofiltration membrane which is the mainstream in commercial products is a polypiperazine amide composite membrane, and is prepared by interfacial polymerization of piperazine and trimesoyl chloride on an ultrafiltration membrane supporting layer. Unreacted amine groups (-NH) remain after the interfacial polymerization is completed2) And carboxyl (-COOH) groups can form corresponding charges in a certain solution environment, so that the separation mechanism of the nanofiltration membrane plays an important role in addition to physical screening and electrostatic repulsion.
The reaction rate of interfacial polymerization is extremely fast, about 102-106And the mol/s piperazine is used as a water-phase reaction monomer, has very ideal reaction activity, can be instantly subjected to diffusion polymerization, almost simultaneously stops the reaction, and forms a loose charge separation layer with a specific structure. But the planar structure of piperazine is such that the amine group (-NH-) is2) The radicals can easily absorb carbon dioxide in air in aqueous solution, and lose the activity of interfacial polymerization reaction. This feature even allows some researchers such as Yuhui to study the application of piperazine aqueous solution as carbon dioxide absorbent, and the result is better. For the research of the polypiperazine amide nanofiltration composite membrane, the piperazine aqueous phase solution is continuously oxidized in the air, so that the piperazine aqueous phase solution is aliveThe concentration of the sexual group is continuously reduced, which is shown in the way that the piperazine water solution is placed in the air with open mouth and slowly stirred, and the pH value is rapidly reduced. And the water phase solution in the common nanofiltration membrane manufacturing process in China is reused, so that the performance of the nanofiltration membrane prepared after interfacial polymerization has larger fluctuation, and even the nanofiltration membrane can not be completely formed. The phenomenon and the corresponding solution are not reported in papers and patents, and no consideration is given to the high equipment investment and the long equipment modification, so that in the production process of 7, only a series of experiments, debugging and groping can be tried to perform complicated composition compensation to stabilize the performance of the nanofiltration membrane product. The result is only satisfactory in terms of the evaluation of the product performance of the mainstream in the domestic market at present.
Some buffer system components are often generated in a water phase formula for polyamide polymerization developed in a laboratory, and some salts are often added to be used as a phase transfer catalyst, so that reaction monomers are promoted to break through an interface to be polymerized more fully and thoroughly, the moisturizing effect of a bottom membrane is considered, and the excellent water permeability of a nanofiltration membrane is ensured. In order to simplify the formulation components to the maximum extent, whether the salt of the phase transfer catalyst and the reaction monomer can be both included in the buffer system or not is considered, and an acidic component is additionally added and mixed in a specific ratio to form a buffer system with a multi-component composition. On one hand, the influence of carbon dioxide on the carbon dioxide is minimized as much as possible; on the other hand, the concentration of reactive amine groups participating in the polymerization reaction is balanced. The innovation point of the invention is that the amine monomer is brought into a buffer system, the effect of storing and releasing the polymerization reaction active group is realized through the linkage mechanism of three components, and the amine monomer can be repeatedly used as the interfacial polymerization aqueous phase solution without external supplement. Meanwhile, the comprehensive performance of the prepared membrane is considered, the aliphatic quaternary ammonium salt with excellent phase conversion catalysis effect is selected, the diffusion speed and the reaction degree of the polymerization reaction of the two-phase monomers are effectively improved, and the function of regulating and controlling the structure and the composition of the polyamide separation layer is achieved. On the other hand, the salt is also a moisture-retaining component and can better protect the water channel of the basement membrane in the heat treatment process. The water-soluble straight-chain organic weak acid with good organic phase solubility is matched, the capability of the water-soluble straight-chain organic weak acid combined with the monomer to participate in reaction and break through the full polymerization of an interface is improved, a separation layer with unique loose and chargeability can be formed in a polyamide structure, and finally excellent comprehensive separation performance is shown.
Disclosure of Invention
The invention aims to provide a novel buffer system with a water phase formula, wherein a reactive amine monomer is creatively brought into the buffer system, an aliphatic quaternary ammonium salt phase transfer catalyst and a water-soluble straight chain weak acid are matched and mixed according to a specific proportion to be used as a buffer system of a water phase solution, and the solution is opened, slowly stirred and placed in the air, and the pH value is stable. The stable water phase state can be realized only by controlling the component proportion of the water phase amine monomer in production, and the nanofiltration composite membrane with market competitiveness can be prepared by repeated use.
From the analysis of reaction mechanism, the invention utilizes the amino characteristics of the reaction monomer, matches weak acid and quaternary ammonium salt with the amino characteristics, and prepares a buffer system in an alkaline range according to a specific proportion. The amine group participates in the construction of a buffer system, and part of activity is blocked, so that the influence of carbon dioxide in the air on the buffer system can be minimized, and the buffer system can also be used as a strategic reserve of a subsequent reactive end group. When the water phase repeatedly used monomers are gradually consumed, the buffer system is in complex linkage, and the amino group with the reactivity is slowly released, so that the effect of stabilizing the concentration of the reactive group in the water phase is achieved. The method has the advantages that the phase transfer catalytic property and the moisturizing effect of the aliphatic quaternary ammonium salt are considered, the positive influence of the linear chain weak acid participating in monomer composition on the reaction degree and the polyamide structure is matched, and the loose charged nanofiltration composite membrane with good water permeability can be stably prepared by repeatedly using the water phase. After the basic functional components of the buffer system are determined, the quaternary ammonium salt in the buffer system can be replaced by adding quaternary ammonium base components by increasing the amount of weak acid in consideration of acid-base salt forming reaction.
The invention is realized by the following technical scheme:
a method for preparing a composite nanofiltration membrane by using an amine monomer to participate in a co-constructed multi-buffering system comprises the steps of dissolving and mixing polyamine, an organic weak acid and a quaternary ammonium salt or/and a quaternary ammonium base capable of reacting with an organic acid to form a salt according to a certain proportion to obtain a water phase buffering formula, and preparing a water phase solution in advance; and coating or immersing the water phase solution on an ultrafiltration basal membrane, drying in the shade, coating an organic phase solution containing the polyacyl chloride, and performing heat treatment at a certain temperature for a certain time to obtain the nanofiltration membrane. The supporting base membrane commonly used in industry is optimized, the types and the component proportions of polyamine, organic weak acid, quaternary ammonium salt or/and quaternary ammonium base in the water phase buffer formula are optimized, the types and the adding amount of the polyacyl chloride monomer are optimized, and the heat treatment temperature and time are optimized according to the performance of the organic phase solvent, so that the water phase can be repeatedly used to prepare the nanofiltration composite membrane with stable performance and high comprehensive performance.
In the preparation method, the water phase formula contains one or more polyamines in piperazine, m-phenylenediamine and polyethyleneimine; one or more organic weak acids selected from acetic acid, acrylic acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, isovaleric acid, n-hexanoic acid, n-heptanoic acid and n-octanoic acid; one or more quaternary ammonium salts of tetramethylammonium chloride, methyltriethylammonium chloride, methyltrioctylammonium chloride, dodecyltrimethylammonium chloride, tetraethylammonium chloride, tetramethylammonium hydroxide, tetramethylammonium acetate, tetramethylammonium bicarbonate, tetraethylammonium hydroxide and tetraethylammonium bicarbonate or/and quaternary ammonium bases which can react with organic acids to form salts. The polyamine-organic weak acid-quaternary ammonium salt or/and quaternary ammonium base comprise the following components in a weight ratio of 1: 0.1-10: 1-50 parts of the mixture is uniformly mixed to be used as a buffer system of the aqueous phase solution.
Most preferably, the aqueous phase buffer formula is prepared by mixing piperazine, n-octanoic acid and dodecyl trimethyl ammonium chloride in a weight ratio of 1: 0.1-5: 1-30 are mixed and prepared; or piperazine, n-octanoic acid, tetraethylammonium hydroxide in a weight ratio of 1: 1-20: 1-20 are mixed and prepared; or piperazine, caprylic acid, dodecyl trimethyl ammonium chloride and tetraethyl ammonium hydroxide are mixed according to the weight ratio of 1: 1-20: 1-30: 1-20 are mixed and prepared. Preferably, the aqueous solution has a buffering effect in the pH range of 8 to 11.
Preferably, in the above preparation method, the ultrafiltration membrane specifically comprises: the flat ultrafiltration membrane or the hollow fiber ultrafiltration membrane is prepared from one or more materials of polysulfone, polyethersulfone, polyacrylonitrile, polyvinylidene fluoride and polytetrafluoroethylene. Most preferably, a polysulfone flat ultrafiltration membrane is selected.
In the above-mentioned preparation method, the organic phase solution containing the further applied poly-acyl chloride, specifically, one or more of trimesoyl chloride, chlorine phthalate, chlorine isophthalate, adipoyl chloride and hexamethylene diisocyanate is dissolved in an organic solvent such as n-hexane, Isopar G of isoparaffin or Isopar L, and in the most preferable case, trimesoyl chloride is selected as the reactive monomer in the oil phase solution, and the mass percentage is 0.05-5%.
In the preparation method, the final heat treatment at a certain temperature and time can be controlled by an oven, and the characteristics of the selected oil phase solvent are preferably combined, wherein the heat treatment temperature ranges from 40 ℃ to 80 ℃ for about 2-5min if n-hexane is used, the heat treatment temperature ranges from 60 ℃ to 100 ℃ for about 2-6min if Isopar G is used, the heat treatment temperature ranges from 80 ℃ to 120 ℃ for about 2-6min if Isopar L is used, and the performance of the prepared nanofiltration membrane is better.
Has the advantages that: the buffering formula disclosed by the invention is simple in composition, and the water phase solution which can be repeatedly used without being supplemented can be realized by controlling the proportion of the added components, so that the buffering formula is used for continuously producing and preparing the polyamide nanofiltration composite membrane with excellent performance. The invention has high matching degree with the prior production process, and the prepared nanofiltration membrane has stable performance and market competitiveness. Not only fundamentally ensures the large-scale production of the nanofiltration membrane product, but also greatly reduces the production cost, and has very good industrial application prospect.
The multi-element buffer aqueous phase solution can be repeatedly used after being prepared once, and the performance of the nanofiltration membrane prepared under the same condition is stable. The innovation of the invention is that the amine reaction monomer is brought into the buffer solution system, thereby effectively solving the problem that the amine monomer is easy to be oxidized and lose the reaction activity, and also solving the problem that the membrane product performance fluctuates due to the consumption of the amine monomer in the process of water-phase reverse reuse in the production, thereby fundamentally ensuring the continuous production of the nanofiltration composite membrane, reducing the consumption of the water phase, simultaneously improving the stability of the product performance and greatly reducing the production cost of the nanofiltration membrane.
Detailed Description
The following specifically describes embodiments of the present invention. It should be understood that the following examples are provided by way of illustration only and are not limiting of the present invention.
Three groups of examples are given below, which respectively correspond to polyamine-organic weak acid-quaternary ammonium salt, polyamine-organic weak acid-quaternary ammonium base, polyamine-organic weak acid-quaternary ammonium salt and quaternary ammonium base, and are used as aqueous phase buffer formulas for repeated use, and interfacial polymerization is used for continuously preparing performance test data of the nanofiltration membrane.
The porous support membranes used in the following examples were all commercial polysulfone ultrafiltration membranes (molecular weight cut-off 50,000Da) which were stored in 1% aqueous sodium bisulfite solution from the production date of the polysulfone membrane to the experimental date for less than 30 days. Before the interfacial reaction is carried out to prepare the composite membrane, the porous support membrane is soaked in deionized water for 1 hour in advance, the deionized water is self-made, and the conductivity is less than 10 mu s/cm.
The performance of the polyamide nanofiltration composite membrane was comprehensively evaluated in the following examples using 2000 + -50 mg/L magnesium sulfate, 2000 + -50 mg/L sodium chloride, a test pressure of 70 + -5 psi, a concentrate flow rate of 1.0 + -0.1L/min, an ambient temperature of 25 + -1 deg.C, and a pH of the test solution of 7 + -0.5, a salt rejection calculation using the difference between the electrical conductivities of the test solution and the produced water divided by the electrical conductivity of the test solution, and a water flux, defined as the volume of the composite membrane, L/m, permeated by deionized water per unit time and unit area under the conditions of the above-mentioned single salt test, in L/m2H (L MH). each of the above data points was averaged over 9 samples.
Carrying out group A
An aqueous phase A: the following examples used aqueous solutions prepared in one step in advance, from piperazine, n-octanoic acid and dodecyltrimethylammonium chloride in a 0.25% ratio: 0.2%: 2% of the solution is a polybasic buffer system, and the pH value of the solution is 10.18. The product is placed in an open mouth for repeated use. The aromatic polybasic acyl chloride monomer is trimesoyl chloride, and the organic phase solvent is n-hexane.
Example A1
The polysulfone ultrafiltration membrane is completely immersed in a water phase A prepared in advance (pH is 10.18), the polysulfone ultrafiltration membrane is taken out after 1min, the upper surface of the polysulfone ultrafiltration membrane is contacted with an organic phase solution containing 0.15% of trimesoyl chloride for 30s, the organic solvent on the surface is removed, then the polysulfone ultrafiltration membrane is placed in an oven for 5min for heat treatment, the temperature of the oven is 80 ℃, the polysulfone ultrafiltration membrane is taken out and immersed in deionized water for testing, and the nanofiltration composite membrane prepared by the method has the pure water flux of 63L MH, the magnesium sulfate rejection rate of 97.9% and the sodium chloride rejection rate of 52.5%.
Example A2
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a1 (pH 10.19.) all other conditions were the same as in example a 1. the nanofiltration membrane prepared had a pure water flux of 67L MH, a magnesium sulfate rejection of 97.5%, and a sodium chloride rejection of 53.6%.
Example A3
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a2 (pH 10.18.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 97.7% and a sodium chloride rejection of 51.6%.
Example A4
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a3 (pH 10.18.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 97.8% and a sodium chloride rejection of 52.9%.
Example A5
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a4 (pH 10.18.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 62L MH, a magnesium sulfate rejection of 97.1% and a sodium chloride rejection of 50.7%.
Example A6
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a5 (pH 10.17.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 61L MH, a magnesium sulfate rejection of 97.0% and a sodium chloride rejection of 55.8%.
Example A7
The polysulfone ultrafiltration membrane was fully immersed in the aqueous solution used in example a6 (pH 10.18.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 62L MH, a magnesium sulfate rejection of 97.4% and a sodium chloride rejection of 57.0%.
Example A8
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a7 (pH 10.18.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 97.6% and a sodium chloride rejection of 52.8%.
Example A9
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example A8 (pH 10.17.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 62L MH, a magnesium sulfate rejection of 97.6% and a sodium chloride rejection of 50.3%.
Example A10
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a9 (pH 10.17.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 97.5% and a sodium chloride rejection of 55.2%.
Example A11
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a10 (pH 10.16.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 97.4% and a sodium chloride rejection of 51.9%.
Example A12
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example a11 (pH 10.17.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 62L MH, a magnesium sulfate rejection of 97.5% and a sodium chloride rejection of 53.9%.
Table 1 summary of performance of the practice group a
EXAMPLE group B
And the water phase B is a water phase solution prepared in advance in one time, a multi-element buffer system is formed by 0.3 percent, 0.8 percent and 0.8 percent of piperazine, n-octanoic acid and tetraethylammonium hydroxide, the pH value of the solution is 10.35, the solution is left open and is repeatedly used, the aromatic polybasic acyl chloride monomer is trimesoyl chloride, and the organic phase solvent is Isopar L.
Example B1
The polysulfone ultrafiltration membrane is completely immersed in a pre-prepared water phase solution B (pH is 10.35), the polysulfone ultrafiltration membrane is taken out after 1min, the upper surface of the polysulfone ultrafiltration membrane is contacted with an organic phase solution containing 0.15% of trimesoyl chloride for 30s, the organic solvent on the surface is removed, then the polysulfone ultrafiltration membrane is placed in an oven for 4min for heat treatment, the temperature of the oven is 100 ℃, the polysulfone ultrafiltration membrane is taken out and immersed in deionized water for testing, and the nanofiltration composite membrane prepared by the method has the pure water flux of 51L MH, the magnesium sulfate rejection rate of 98.5% and the sodium chloride rejection rate of 61.0%.
Example B2
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B1 (pH 10.35.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 53L MH, a magnesium sulfate rejection of 98.6% and a sodium chloride rejection of 59.6%.
Example B3
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B2 (pH 10.35.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 50L MH, a magnesium sulfate rejection of 98.5% and a sodium chloride rejection of 60.3%.
Example B4
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B3 (pH 10.35.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 50L MH, a magnesium sulfate rejection of 98.8% and a sodium chloride rejection of 58.9%.
Example B5
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B4 (pH 10.34.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 53L MH, a magnesium sulfate rejection of 98.4% and a sodium chloride rejection of 58.1%.
Example B6
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B5 (pH 10.35.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 55L MH, a magnesium sulfate rejection of 98.6% and a sodium chloride rejection of 58.5%.
Example B7
The polysulfone ultrafiltration membrane was fully immersed in the aqueous solution used in example B6 (pH 10.34.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 52L MH, a magnesium sulfate rejection of 98.4% and a sodium chloride rejection of 58.8%.
Example B8
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B7 (pH 10.34.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 53L MH, a magnesium sulfate rejection of 98.5% and a sodium chloride rejection of 57.7%.
Example B9
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B8 (pH 10.34.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 55L MH, a magnesium sulfate rejection of 98.6% and a sodium chloride rejection of 57.9%.
Example B10
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B9 (pH 10.33.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 54L MH, a magnesium sulfate rejection of 98.4% and a sodium chloride rejection of 55.1%.
Example B11
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B10 (pH 10.34.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 55L MH, a magnesium sulfate rejection of 98.4% and a sodium chloride rejection of 56.5%.
Example B12
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example B11 (pH 10.34.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 53L MH, a magnesium sulfate rejection of 98.3% and a sodium chloride rejection of 55.5%.
Table 2 summary of performance of the embodiment group B
Practice group C
Water phase C: the following examples used previously prepared aqueous solutions in a single step, from 0.4% piperazine, n-octanoic acid, dodecyltrimethylammonium chloride and tetraethylammonium hydroxide: 1.0%: 2.0%: 1.0% of the solution is a polybasic buffer system, and the pH value of the solution is 10.50. The product is placed in an open mouth for repeated use. The aromatic polybasic acyl chloride monomer is trimesoyl chloride, and the organic phase solvent is n-hexane.
Example C1
The polysulfone ultrafiltration membrane is completely immersed in a pre-prepared water phase solution C (pH is 10.49). the polysulfone ultrafiltration membrane is taken out after 1min, the upper surface of the polysulfone ultrafiltration membrane is contacted with an organic phase solution containing 0.15% of trimesoyl chloride for 30s, the organic solvent on the surface is removed, then the polysulfone ultrafiltration membrane is placed in an oven for 3min for heat treatment, the temperature of the oven is 80 ℃, the polysulfone ultrafiltration membrane is taken out and immersed in deionized water to be tested, and the nanofiltration composite membrane prepared by the method has the pure water flux of 58L MH, the magnesium sulfate rejection rate of 98.2% and the sodium chloride rejection rate of 50.1%.
Example C2
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C1 (pH 10.49.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 60L MH, a magnesium sulfate rejection of 98.0% and a sodium chloride rejection of 49.6%.
Example C3
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C2 (pH 10.49.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 60L MH, a magnesium sulfate rejection of 98.1% and a sodium chloride rejection of 51.6%.
Example C4
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C3 (pH 10.49.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 58L MH, a magnesium sulfate rejection of 98.0% and a sodium chloride rejection of 52.9%.
Example C5
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C4 (pH 10.49.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 61L MH, a magnesium sulfate rejection of 98.1% and a sodium chloride rejection of 50.7%.
Example C6
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C5 (pH 10.48.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 61L MH, a magnesium sulfate rejection of 98.0% and a sodium chloride rejection of 49.8%.
Example C7
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C6 (pH 10.48.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 62L MH, a magnesium sulfate rejection of 98.0% and a sodium chloride rejection of 49.0%.
Example C8
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C7 (pH 10.48.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 97.9% and a sodium chloride rejection of 49.8%.
Example C9
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C8 (pH 10.48.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 62L MH, a magnesium sulfate rejection of 97.9% and a sodium chloride rejection of 50.3%.
Example C10
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C9 (pH 10.48.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 98.0% and a sodium chloride rejection of 49.2%.
Example C11
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C10 (pH 10.48.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 63L MH, a magnesium sulfate rejection of 98.0% and a sodium chloride rejection of 51.0%.
Example C12
The polysulfone ultrafiltration membrane was completely immersed in the aqueous solution used in example C11 (pH 10.48.) all other conditions were the same as in example 1. the nanofiltration membrane prepared had a pure water flux of 62L MH, a magnesium sulfate rejection of 97.9% and a sodium chloride rejection of 51.9%.
Table 3 summary of performance of the embodiment group C
Claims (10)
1. A method for preparing a composite nanofiltration membrane by using a multi-element buffer system is characterized by comprising the following steps: dissolving and mixing polyamine, organic weak acid and quaternary ammonium salt or/and quaternary ammonium base capable of reacting with the organic weak acid to form salt according to a certain proportion to obtain a water phase buffer formula; coating an aqueous phase solution containing the buffering formula on an ultrafiltration basal membrane, coating an organic phase solution containing the polyacyl chloride, and then carrying out heat treatment at a certain temperature for a certain time to obtain a nanofiltration membrane;
the polyamine contained in the water phase buffer formula specifically comprises the following components: one or more of piperazine, m-phenylenediamine and polyethyleneimine;
wherein, the organic weak acid contained in the aqueous phase buffer formula specifically comprises: one or more of acetic acid, acrylic acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, isovaleric acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid;
the quaternary ammonium salt or/and quaternary ammonium base capable of reacting with organic weak acid to form salt in the water phase buffer formula are specifically as follows: one or more of tetramethylammonium chloride, methyltriethylammonium chloride, methyltrioctylammonium chloride, dodecyltrimethylammonium chloride, tetraethylammonium chloride, tetramethylammonium hydroxide, tetramethylammonium acetate, tetramethylammonium bicarbonate, tetraethylammonium hydroxide and tetraethylammonium bicarbonate;
wherein the polyamine-organic weak acid-quaternary ammonium salt and/or quaternary ammonium base in the aqueous phase solution is present in a weight ratio of 1: 0.1-10: 1-50, mixing uniformly;
the ultrafiltration basement membrane is specifically as follows: the flat ultrafiltration membrane or the hollow fiber ultrafiltration membrane is prepared from one or more materials of polysulfone, polyethersulfone, polyacrylonitrile, polyvinylidene fluoride and polytetrafluoroethylene.
2. The method for preparing a composite nanofiltration membrane by using a multi-element buffer system according to claim 1, wherein the organic phase solution containing poly-acid chloride, specifically one or more of trimesoyl chloride, chlorine phthalate, chlorine isophthalate, adipoyl chloride and hexamethylene diisocyanate, is dissolved in an organic solvent such as n-hexane, Isopar G of isoparaffin, or Isopar L.
3. The method for preparing the composite nanofiltration membrane according to claim 1, wherein the polyamine is piperazine, and the mass percentage of the polyamine in the aqueous solution is 0.05-5%.
4. The method for preparing a composite nanofiltration membrane according to claim 1, wherein the weak organic acid is caprylic acid, and the weak organic acid accounts for 0.01-2% of the volume of the aqueous solution.
5. The method for preparing a composite nanofiltration membrane according to claim 1, wherein the quaternary ammonium salt is dodecyl trimethyl ammonium chloride, and the mass percentage of the quaternary ammonium salt in the aqueous solution is 0.05-5%.
6. The method for preparing the composite nanofiltration membrane by using the multi-element buffer system as claimed in claim 1, wherein the weight ratio of the polyamine, the organic weak acid and the quaternary ammonium salt is 1: 0.1-5: 1-30, mixing uniformly;
or, the polyamine-organic weak acid-quaternary ammonium base comprises three components according to the weight ratio of 1: 1-20: 1-20, mixing uniformly;
or, the four components of polyamine-organic weak acid-quaternary ammonium salt and quaternary ammonium base are mixed according to the weight ratio of 1: 1-20: 1-30: 1-20, and mixing uniformly.
7. The method for preparing a composite nanofiltration membrane according to claim 1, wherein the quaternary ammonium base capable of reacting with the weak organic acid to form a salt is tetraethylammonium hydroxide, and the quaternary ammonium base accounts for 0.01-2% by mass of the aqueous solution.
8. The method for preparing the composite nanofiltration membrane by using the multi-element buffer system as claimed in claim 1, wherein the pH value of the aqueous phase solution is controlled to be 8-11.
9. The method for preparing the composite nanofiltration membrane by using the multi-element buffer system as claimed in claim 2, wherein the organic phase solution containing poly-acid chloride, specifically trimesoyl chloride, is dissolved in n-hexane, Isopar G of isoparaffin, or Isopar L.
10. The method for preparing the composite nanofiltration membrane by using the multi-element buffer system as claimed in claim 1, wherein in the heat treatment process, n-hexane is used as an organic solvent for dissolving the multi-element acyl chloride, so that the heat treatment temperature is in the range of 40-80 ℃, and the treatment time is 2-5 min;
or Isopar G is used as an organic solvent for dissolving the polybasic acyl chloride, the heat treatment temperature ranges from 60 ℃ to 100 ℃, and the treatment time is 2-6 min;
or Isopar L is used as organic solvent for dissolving polybasic acyl chloride, and the heat treatment temperature is 80-120 deg.C for 2-6 min.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114904399A (en) * | 2022-06-06 | 2022-08-16 | 山东中康国创先进印染技术研究院有限公司 | Interface polymerization method based on eutectic solvent and alkane, polyamide composite membrane and preparation method thereof |
| CN115337801A (en) * | 2022-08-17 | 2022-11-15 | 中国科学技术大学 | High-performance thin film composite nanofiltration membrane, and preparation method and application thereof |
| CN115738742A (en) * | 2022-12-05 | 2023-03-07 | 蓝星（杭州）膜工业有限公司 | Salt lake lithium-extracting charged positive membrane and preparation method thereof |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0640008A1 (en) * | 1992-05-13 | 1995-03-01 | Fluid Sys Corp | Thin-film composite membrane. |
| TW396202B (en) * | 1997-02-14 | 2000-07-01 | Ekc Technology Inc | Buffered organic acid compositions for cleaning or chemical mechanical polishing |
| CN104474926A (en) * | 2014-12-12 | 2015-04-01 | 杭州水处理技术研究开发中心有限公司 | Preparation method of polyamide reverse osmosis membrane |
| CN109569308A (en) * | 2018-11-16 | 2019-04-05 | 杭州水处理技术研究开发中心有限公司 | A kind of acid absorbent system prepares the preparation method of high-flux reverse osmosis membrane |
| CN109603586A (en) * | 2018-11-16 | 2019-04-12 | 蓝星（杭州）膜工业有限公司 | A kind of preparation method of the high-flux nanofiltration membrane based on new buffer system |
| CN109821427A (en) * | 2019-03-22 | 2019-05-31 | 江南大学 | A kind of preparation method of chlorine-resistant aromatic polyamides composite nanometer filtering film |
| CN110449045A (en) * | 2019-08-01 | 2019-11-15 | 蓝星（杭州）膜工业有限公司 | A kind of preparation method of the high-flux nanofiltration membrane based on new buffer system |
| CN110975620A (en) * | 2019-12-25 | 2020-04-10 | 恩泰环保科技（常州）有限公司 | Nanofiltration membrane based on weak base buffer system and preparation method thereof |
| CN110975621A (en) * | 2019-12-25 | 2020-04-10 | 恩泰环保科技（常州）有限公司 | Reverse osmosis membrane based on weak base-weak acid buffer system and preparation method thereof |
-
2020
- 2020-04-17 CN CN202010303658.5A patent/CN111450714A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0640008A1 (en) * | 1992-05-13 | 1995-03-01 | Fluid Sys Corp | Thin-film composite membrane. |
| TW396202B (en) * | 1997-02-14 | 2000-07-01 | Ekc Technology Inc | Buffered organic acid compositions for cleaning or chemical mechanical polishing |
| CN104474926A (en) * | 2014-12-12 | 2015-04-01 | 杭州水处理技术研究开发中心有限公司 | Preparation method of polyamide reverse osmosis membrane |
| CN109569308A (en) * | 2018-11-16 | 2019-04-05 | 杭州水处理技术研究开发中心有限公司 | A kind of acid absorbent system prepares the preparation method of high-flux reverse osmosis membrane |
| CN109603586A (en) * | 2018-11-16 | 2019-04-12 | 蓝星（杭州）膜工业有限公司 | A kind of preparation method of the high-flux nanofiltration membrane based on new buffer system |
| CN109821427A (en) * | 2019-03-22 | 2019-05-31 | 江南大学 | A kind of preparation method of chlorine-resistant aromatic polyamides composite nanometer filtering film |
| CN110449045A (en) * | 2019-08-01 | 2019-11-15 | 蓝星（杭州）膜工业有限公司 | A kind of preparation method of the high-flux nanofiltration membrane based on new buffer system |
| CN110975620A (en) * | 2019-12-25 | 2020-04-10 | 恩泰环保科技（常州）有限公司 | Nanofiltration membrane based on weak base buffer system and preparation method thereof |
| CN110975621A (en) * | 2019-12-25 | 2020-04-10 | 恩泰环保科技（常州）有限公司 | Reverse osmosis membrane based on weak base-weak acid buffer system and preparation method thereof |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114904399A (en) * | 2022-06-06 | 2022-08-16 | 山东中康国创先进印染技术研究院有限公司 | Interface polymerization method based on eutectic solvent and alkane, polyamide composite membrane and preparation method thereof |
| CN115337801A (en) * | 2022-08-17 | 2022-11-15 | 中国科学技术大学 | High-performance thin film composite nanofiltration membrane, and preparation method and application thereof |
| CN115337801B (en) * | 2022-08-17 | 2024-02-09 | 中国科学技术大学 | High-performance film composite nanofiltration membrane, preparation method and application thereof |
| CN115738742A (en) * | 2022-12-05 | 2023-03-07 | 蓝星（杭州）膜工业有限公司 | Salt lake lithium-extracting charged positive membrane and preparation method thereof |
| CN115738742B (en) * | 2022-12-05 | 2023-06-13 | 蓝星（杭州）膜工业有限公司 | Positive charged membrane for extracting lithium from salt lake and preparation method thereof |
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