Composition for forming active layer of separation membrane, method for manufacturing separation membrane, and water treatment module
阅读说明：本技术 用于形成分离膜活性层的组合物、用于制造分离膜的方法、分离膜、以及水处理模块 (Composition for forming active layer of separation membrane, method for manufacturing separation membrane, and water treatment module ) 是由 康惠琳 崔洛援 申惠子 李佳贤 申程圭 于 2020-04-22 设计创作，主要内容包括：本说明书提供了：用于形成分离膜活性层的组合物；用于制造分离膜的方法；分离膜；以及水处理模块。(The present specification provides: a composition for forming an active layer of a separation membrane; a method for manufacturing a separation membrane; a separation membrane; and a water treatment module.)
1. A composition for forming an active layer of a separation membrane, the composition comprising a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2,
wherein the percentage (a/b) of the weight (a) of the compound represented by the following chemical formula 1 with respect to the weight (b) of the compound represented by the following chemical formula 2 is 30% to 60%, and
the pH of the composition is from 11 to 12.7:
[ chemical formula 1]
[ chemical formula 2]
In the chemical formulae 1 and 2,
r1 to R16 are the same or different from each other and are each independently-CRR' -; or-NR' -,
at least two of R1 to R10 are-NR ",
at least two of R11 to R16 are-NR "-, and
r, R 'and R' are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group.
2. The composition of claim 1, wherein R3, R8, R12, and R15 are-NR "-, and
r "is the same as those defined in chemical formulas 1 and 2.
3. The composition according to claim 1, wherein the compound represented by chemical formula 1 and the compound represented by chemical formula 2 are each included in an amount of 0.1 to 0.3% by weight, based on the total weight of the composition for forming an active layer.
4. The composition of claim 1, further comprising: a surfactant; a hydrophilic polymer compound; and a solvent.
5. A method for manufacturing a separation membrane, the method comprising:
preparing a porous layer; and
manufacturing an active layer on the porous layer using the composition according to any one of claims 1 to 4, the composition comprising a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2, wherein a percentage (a/b) of a weight (a) of the compound represented by the following chemical formula 1 with respect to a weight (b) of the compound represented by the following chemical formula 2 is 30% to 60%, and a pH of the composition is 11 to 12.7:
[ chemical formula 1]
[ chemical formula 2]
In the chemical formulae 1 and 2,
r1 to R16 are the same or different from each other and are each independently-CRR' -; or-NR' -,
at least two of R1 to R10 are-NR ",
at least two of R11 to R16 are-NR "-, and
r, R 'and R' are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group.
6. The method according to claim 5, wherein manufacturing the active layer using the composition for forming an active layer includes interfacial polymerization of the composition for forming an active layer and an organic solution containing an acid halide compound.
7. The method of claim 5, wherein preparing the porous layer comprises:
preparing a first porous support; and
a second porous support is fabricated on the first porous support.
8. The method of claim 7, wherein the first porous support is a nonwoven fabric, and
the second porous support is a polysulfone layer.
9. The method of claim 5, further comprising:
after the active layer is fabricated, a protective layer is fabricated on the active layer.
10. A separation membrane made by the process of claim 5, wherein at 2,000ppm of aqueous MgSO4A salt rejection of 99.7% or greater of the solution, a pressure of 130psi, a temperature of 25 ℃, and measured at 4L/min, an
The permeate flux was 21GFD or greater.
11. A separation membrane manufactured by the method according to claim 5, wherein the separation membrane satisfies the following formula 1:
[ equation 1]
0.28≤Aa/Ab≤0.50
In the formula 1, the first and second groups of the compound,
aa means at 1640cm during FT-IR analysis-1An absorbance value at a wavenumber of, and
ab means at 1587cm during FT-IR analysis-1The wavenumber of (2) is used.
12. A water treatment module comprising one or more separation membranes according to claim 10.
Technical Field
The present specification relates to a composition for forming an active layer of a separation membrane, a method for manufacturing a separation membrane, a separation membrane manufactured thereby, and a water treatment module.
This application claims priority and benefit from korean patent application No. 10-2019-0076310 filed by the korean intellectual property office at 26.6.2019, which is incorporated herein by reference in its entirety.
Background
Due to recent serious pollution of water quality environment and water shortage, development of new water resources has become an urgent issue. Research on water quality and environmental pollution is directed to the treatment of high-quality residential and industrial water as well as various domestic and industrial wastewater, and interest in water treatment processes using separation membranes having an energy-saving advantage is increasing. In addition, accelerated enhancement of environmental regulations is expected to advance the excitation of separation membrane technologies. The conventional water treatment process has difficulty in satisfying strict regulations, but the separation membrane technology ensures excellent treatment efficiency and stable treatment, and thus is expected to be a leading technology in the field of water treatment in the future.
Liquid separation is classified into microfiltration, ultrafiltration, nanofiltration, reverse osmosis, tinning (tinning), active transport, electrodialysis, and the like, according to the pores of the membrane.
Among them, a nanofiltration device corresponding to nanofiltration is composed of a porous layer and an active layer, and is a membrane that separates a solvent and a solute using a surface charge of a separation membrane, a size of separated ions, and a reverse osmosis phenomenon. The permeation flux of the nanofilter and the selective rejection rate of ions are used as important indicators of membrane performance, and such performance is greatly influenced by the structure of the active layer manufactured by interfacial polymerization. There is a continuing need to develop methods for improving the performance of such nanofilters.
Disclosure of Invention
Technical problem
The present specification relates to a composition for forming an active layer of a separation membrane, a method for manufacturing a separation membrane, a separation membrane manufactured thereby, and a water treatment module.
Technical scheme
An exemplary embodiment of the present specification provides a composition for forming an active layer of a separation membrane, the composition including a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2,
wherein the percentage (a/b) of the weight (a) of the compound represented by the following chemical formula 1 with respect to the weight (b) of the compound represented by the following chemical formula 2 is 30% to 60%, and
the pH of the composition is from 11 to 12.7.
[ chemical formula 1]
[ chemical formula 2]
In the chemical formulae 1 and 2,
r1 to R16 are the same or different from each other and are each independently-CRR' -; or-NR' -,
at least two of R1 to R10 are-NR ",
at least two of R11 to R16 are-NR "-, and
r, R 'and R' are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group.
An exemplary embodiment of the present specification provides a method for manufacturing a separation membrane, the method including: preparing a porous layer; and
an active layer is manufactured on a porous layer using the above-described composition for forming a separation membrane active layer, the composition comprising a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2, wherein the percentage (a/b) of the weight (a) of the compound represented by the following chemical formula 1 with respect to the weight (b) of the compound represented by the following chemical formula 2 is 30% to 60%, and the pH of the composition is 11 to 12.7.
[ chemical formula 1]
[ chemical formula 2]
In the chemical formulae 1 and 2,
r1 to R16 are the same or different from each other and are each independently-CRR' -; or-NR' -,
at least two of R1 to R10 are-NR ",
at least two of R11 to R16 are-NR "-, and
r, R 'and R' are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group.
An exemplary embodiment of the present specification provides a separation membrane manufactured by the above-described method for manufacturing a separation membrane, wherein the aqueous MgSO at 2,000ppm4A salt rejection of 99.7% or greater, and a permeate flux of 21GFD or greater, measured at conditions of solution, pressure of 130psi, temperature of 25 ℃, and 4L/min.
An exemplary embodiment of the present specification provides a separation membrane manufactured by the above-described method for manufacturing a separation membrane, wherein the separation membrane satisfies the following formula 1.
[ equation 1]
0.28≤Aa/Ab≤0.50
In the formula 1, the first and second groups of the compound,
aa means at 1640cm during FT-IR analysis-1An absorbance value at a wavenumber of, and
ab means at 1587cm during FT-IR analysis-1The wavenumber of (2) is used.
In addition, an exemplary embodiment of the present specification provides a water treatment module including one or more of the above-described separation membranes.
Advantageous effects
When a separation membrane is manufactured using the composition for forming an active layer of a separation membrane according to one exemplary embodiment of the present specification, salt rejection and permeation flux of the separation membrane may be improved.
Drawings
Fig. 1 shows a separation membrane according to an exemplary embodiment of the present description.
FIG. 2 illustrates a water treatment module according to an exemplary embodiment of the present description.
Best mode for carrying out the invention
In this specification, when one member is provided "on" another member, this includes not only a case where one member is in contact with another member but also a case where another member exists between the two members.
In the present specification, when a portion "includes" one constituent element, unless specifically described otherwise, this does not mean that another constituent element is excluded, but means that another constituent element may be further included.
In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms thereof is not particularly limited, but may be 1 to 30, may be 1 to 20, and may preferably be 1 to 10. Specific examples thereof include methyl group, ethyl group, propyl group, n-propyl group, isopropyl group, butyl group, n-butyl group, isobutyl group, tert-butyl group, sec-butyl group, 1-methyl-butyl group, 1-ethyl-butyl group, pentyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, n-hexyl group, 1-methylpentyl group, 2-methylpentyl group, 4-methyl-2-pentyl group, 3-dimethylbutyl group, 2-ethylbutyl group, heptyl group, n-heptyl group, 1-methylhexyl group, cyclopentylmethyl group, cyclohexylmethyl group, octyl group, n-octyl group, tert-octyl group, 1-methylheptyl group, 2-ethylhexyl group, 2-propylpentyl group, n-nonyl group, 2-dimethylheptyl group, 1-ethyl-propyl group, 1-dimethyl-propyl group, Isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, and the like, but are not limited thereto.
In the present specification, the cycloalkyl group is not particularly limited, but according to an exemplary embodiment, the number of carbon atoms of the cycloalkyl group is 3 to 30. According to yet another exemplary embodiment, the number of carbon atoms of the cycloalkyl group is from 3 to 20. According to yet another exemplary embodiment, the number of carbon atoms of the cycloalkyl group is from 3 to 10. Specific examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and the like, but are not limited thereto.
In this specification, alkylene means that there are two bonding sites in an alkane. The alkylene group may be linear, branched or cyclic. The number of carbon atoms of the alkylene group is not particularly limited, but is, for example, 1 to 30, specifically 1 to 20, and more specifically 1 to 10.
In the present specification, cycloalkylene means that there are two bonding positions in cycloalkane. The description of cycloalkyl groups above can be applied to cycloalkanes.
Hereinafter, the present specification will be described in more detail.
An exemplary embodiment of the present specification provides a composition for forming an active layer of a separation membrane, the composition including a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2, wherein a percentage (a/b) of a weight (a) of the compound represented by the following chemical formula 1 with respect to a weight (b) of the compound represented by the following chemical formula 2 is 30% to 60%, and a pH of the composition is 11 to 12.7.
[ chemical formula 1]
[ chemical formula 2]
In the chemical formulae 1 and 2,
r1 to R16 are the same or different from each other and are each independently-CRR' -; or-NR' -,
at least two of R1 to R10 are-NR ",
at least two of R11 to R16 are-NR "-, and
r, R 'and R' are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group.
When the composition for forming an active layer according to the present specification includes both the compound represented by chemical formula 1 and the compound represented by chemical formula 2, the permeation flux of the separation membrane is improved due to an increase in the size of pores included in the active layer.
In addition, when the percentage (a/b) of the weight (a) of the compound represented by chemical formula 1 with respect to the weight (b) of the compound represented by chemical formula 2 is 30% to 60%, the permeation flux may be improved without decreasing the salt rejection of the separation membrane.
In addition, when the pH of the composition for forming an active layer is 11 to 12.7, the salt rejection rate and the permeation flux of the separation membrane may be further improved by the principle of neutralization of HCl generated after the reaction of the compound represented by chemical formula 1 or the compound represented by chemical formula 2 with the acid halide compound. Preferably, the pH of the composition for forming the active layer may be 12 to 12.5.
In an exemplary embodiment of the present specification, R1 to R16 are the same as or different from each other and are each independently-CRR' -; or-NR "-.
In an exemplary embodiment of the present specification, R3, R8, R12 and R15 are-NR "-, and R" is the same as those defined in chemical formulas 1 and 2.
In an exemplary embodiment of the present description, at least two of R1 through R10 are-NR' -.
In an exemplary embodiment of the present description, at least two of R11 through R16 are-NR' -.
In an exemplary embodiment of the present description, R, R' and R "are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group.
In an exemplary embodiment of the present description, R, R' and R "are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms.
In an exemplary embodiment of the present description, R, R' and R "are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.
In an exemplary embodiment of the present description, R, R' and R "are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms.
In an exemplary embodiment of the present description, R, R' and R "are each hydrogen.
In one exemplary embodiment of the present specification, chemical formula 1 may be represented by the following chemical formula, but is not limited thereto.
In one exemplary embodiment of the present specification, chemical formula 2 may be represented by the following chemical formula, but is not limited thereto.
In one exemplary embodiment of the present specification, the compound represented by chemical formula 1 and the compound represented by chemical formula 2 are each included in an amount of 0.1 to 0.3% by weight, based on the total weight of the composition for forming an active layer.
Preferably, the compound represented by chemical formula 1 and the compound represented by chemical formula 2 are each included in an amount of 0.11 to 0.25% by weight, based on the total weight of the composition for forming the active layer.
Specifically, the compound represented by chemical formula 1 is included in an amount of 0.11 to 0.21 wt% based on the total weight of the composition for forming an active layer.
More specifically, the compound represented by chemical formula 2 is included in an amount of 0.14 to 0.25 wt% based on the total weight of the composition for forming the active layer.
When the compound represented by chemical formula 1 and the compound represented by chemical formula 2 each satisfy the above weight range, permeation flux may be improved without decreasing salt rejection.
In one exemplary embodiment of the present specification, the pH of the composition for forming the active layer of the separation membrane is 11 to 12.7.
When the composition for forming the active layer satisfies the above pH range, the active layer polymerization reaction can be performed, and thus the salt rejection of the separation membrane can be ensured to be 97% or more, preferably 99.7% or more.
When the pH of the composition for forming the active layer is less than 11, the active layer polymerization does not occur, and when the pH is greater than 12.7, the salt rejection of the separation membrane is significantly reduced to less than 95%.
The composition for forming an active layer may further include salts of triethylamine and camphorsulfonic acid.
The salts of triethylamine and camphorsulfonic acid in the composition for forming an active layer may be included in an amount of 4 to 9% by weight, based on the total weight of the composition for forming an active layer. Preferably, the salts of triethylamine and camphorsulfonic acid may be included in an amount of 5 to 7 wt%.
In addition, the composition for forming the active layer may include sodium hydroxide (NaOH) to satisfy a pH range of the composition for forming the active layer.
An exemplary embodiment of the present specification provides a composition for forming an active layer of a separation membrane, the composition further comprising: a surfactant; a hydrophilic polymer compound; and a solvent.
As the surfactant, for example, Sodium Lauryl Sulfate (SLS) or sodium dodecylbenzenesulfonate may be used, but the surfactant is not limited thereto. Preferably, the surfactant may be Sodium Lauryl Sulfate (SLS).
The surfactant may be included in the composition for forming the active layer in an amount of 0.05% to 1% by weight, based on the total weight of the composition for forming the active layer. When the surfactant is contained within the above range, the composition for forming an active layer has an effect of being uniformly applied to the surface of the porous layer.
Examples of the hydrophilic polymer compound include polyvinyl alcohol (PVA), polyethylene oxide, polyacrylic acid, and polyethylene glycol, but are not limited thereto. Preferably, the hydrophilic polymer compound may be polyvinyl alcohol (PVA).
The hydrophilic polymer compound may be included in the composition for forming an active layer in an amount of 0.05 to 1% by weight, based on the total weight of the composition for forming an active layer. When the hydrophilic polymer compound is contained within the above range, the mechanical strength of the active layer can be ensured.
The solvent may be water, and the remaining portion obtained by removing the amine compound from the composition for forming the active layer may be water.
An exemplary embodiment of the present specification provides a method for manufacturing a separation membrane, the method including: preparing a porous layer; and manufacturing an active layer on the porous layer using the above composition for forming a separation membrane active layer, the composition comprising a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2, wherein a percentage (a/b) of a weight (a) of the compound represented by the following chemical formula 1 with respect to a weight (b) of the compound represented by the following chemical formula 2 is 30% to 60%, and a pH of the composition is 11 to 12.7.
[ chemical formula 1]
[ chemical formula 2]
In the chemical formulae 1 and 2,
r1 to R16 are the same or different from each other and are each independently-CRR' -; or-NR' -,
at least two of R1 to R10 are-NR ",
at least two of R11 to R16 are-NR "-, and
r, R 'and R' are the same or different from each other and are each independently hydrogen; or a substituted or unsubstituted alkyl group.
In the method for manufacturing the separation membrane, the definitions of chemical formula 1 and chemical formula 2 are the same as described above.
In one exemplary embodiment of the present specification, the manufacturing of the active layer using the composition for forming the active layer includes interfacial polymerization of the composition for forming the active layer and an organic solution including an acid halide compound.
Specifically, when the composition for forming an active layer is brought into contact with an organic solution, the amine compound and the polyfunctional acyl halide compound coated on the surface of the support layer react with each other while forming a polyamide through interfacial polymerization, and the polyamide is adsorbed on the support layer to form a thin film. In the contact method, the polyamide active layer may be formed by a method such as dipping, spraying, or coating.
The organic solution containing an acid halide compound contains an acid halide compound and an organic solvent.
According to an exemplary embodiment of the present specification, the acid halide compound is not particularly limited, but for example, as the aromatic compound having 2 to 3 carboxylic acid halides, may be a mixture of one or more selected from the group consisting of: trimesoyl chloride (TMC), isophthaloyl chloride, terephthaloyl chloride, and mixtures thereof. Preferably, the acid halide compound is trimesoyl chloride (TMC).
According to an exemplary embodiment of the present specification, the content of the acid halide compound may be 0.2 to 0.8% by weight, based on the total weight of the composition for forming the active layer of the reverse osmosis membrane. Preferably, the content of the acid halide compound may be 0.4 to 0.5% by weight.
As the organic solvent, an aliphatic hydrocarbon solvent, for example, freon and a hydrophobic liquid immiscible with water such as hexane, cyclohexane, heptane and alkanes having 5 to 12 carbon atoms, for example, alkanes having 5 to 12 carbon atoms and IsoPar (exxon), ISOL-C (SK Chem.), ISOL-G (exxon), IsoPar G and the like which are mixtures thereof may be used, but the organic solvent is not limited thereto.
According to an exemplary embodiment of the present specification, the remaining portion obtained by removing the acid halide compound from the organic solution containing the acid halide compound may be an organic solvent.
In one exemplary embodiment of the present description, preparing the porous layer includes: preparing a first porous support; and forming a second porous support as a coating layer of a polymer material on the first porous support.
That is, the porous layer includes a first porous support and a second porous support.
In an exemplary embodiment of the present description, the first porous support is a nonwoven fabric and the second porous support is a polysulfone layer.
As the first porous support, a nonwoven fabric may be used. As a material for the nonwoven fabric, polyethylene terephthalate may be used, but the material is not limited thereto.
The thickness of the nonwoven fabric may be 50 μm to 150 μm, but is not limited thereto. Preferably, the thickness may be 80 μm to 120 μm. When the thickness of the nonwoven fabric satisfies the above range, the durability of the gas separation membrane including the porous layer can be maintained.
The second porous support may mean that a coating layer of a polymer material is formed on the first porous support. As the polymer material, for example, polysulfone, polyethersulfone, polycarbonate, polyethylene oxide, polyimide, polyetherimide, polyetheretherketone, polypropylene, polymethylpentene, polymethylchloride, polyvinylidene fluoride, or the like can be used, but the polymer material is not limited thereto. Specifically, as the polymer material, polysulfone may be used. That is, the second porous support is a polysulfone layer.
The thickness of the second porous support may be 20 μm to 200 μm, but is not limited thereto. Preferably, the thickness may be 40 μm to 160 μm. When the thickness of the coating layer satisfies the above range, the durability of the separation membrane including the porous layer including the second porous support can be suitably maintained.
According to one example, the second porous support may be made from a polymer solution comprising polysulfone. The polymer solution comprising polysulfone may be a homogeneous liquid phase obtained after: 10 to 20 wt% of polysulfone solid is put into 80 to 90 wt% of solvent dimethylformamide based on the total weight of the polymer solution including polysulfone, and the resulting mixture is dissolved at 80 to 85 ℃ for 12 hours, but the weight range is not limited to the above range.
When the polysulfone solid is contained within the above range based on the total weight of the polymer solution containing polysulfone, the durability of the separation membrane including the second porous support may be suitably maintained.
The second porous support may be formed by a casting method. Casting means a solution casting method, and specifically may mean a method of: the polymeric material is dissolved in a solvent, the resulting solution is spread on a smooth surface without adhesion, and the solvent is then replaced. Specifically, a non-solvent induced phase separation method may be used as a method for replacing the above solvent. The non-solvent induced phase separation method is as follows: preparing a uniform solution by dissolving a polymer in a solvent, molding the uniform solution into a predetermined shape, and then dipping the resulting molded article in a non-solvent, wherein the non-solvent and the solvent are then exchanged by diffusion of the non-solvent and the solvent, the composition of the polymer solution is changed, and pores are formed in a portion occupied by the solvent and the non-solvent while the polymer is precipitated.
In one exemplary embodiment of the present description, the method further includes fabricating a protective layer on the active layer after fabricating the active layer.
The protective layer is made of a composition for forming the protective layer, and the composition for forming the protective layer includes polyvinyl alcohol, polyethylene glycol, or glycerin. Preferably, the composition for forming the protective layer comprises polyvinyl alcohol.
The polyvinyl alcohol may be included in the composition for forming a protective layer in an amount of 0.1 to 3% by weight, based on the total weight of the composition for forming a protective layer. When the polyvinyl alcohol is included within the above range, the active layer may be protected from physical damage.
In the composition for forming the protective layer, water may be used as a solvent, but the solvent is not limited thereto.
By further including a protective layer, the separation membrane according to the present specification may improve contamination resistance and durability while minimizing a decrease in permeation flux.
The production of the protective layer on the active layer may be carried out, for example, by a method of immersing the porous layer having the polyamide active layer formed therein in the composition for forming the protective layer, and may be carried out by a method of applying the above-described composition for forming the protective layer on the porous layer having the polyamide active layer formed therein, but the method is not limited thereto.
Meanwhile, the immersion time may be appropriately adjusted in consideration of the thickness of the protective layer to be formed, etc., and is, for example, about 0.1 minute to 10 hours, preferably about 1 minute to 1 hour. When the immersion time is less than 0.1 minute, there is a negative effect that the protective layer cannot be sufficiently formed, and when the immersion time is more than 10 hours, there is a negative effect that the thickness of the protective layer becomes too large so that the permeation flux of the separation membrane is reduced.
According to an exemplary embodiment of the present description, the thickness of the protective layer may be 100nm to 300 nm. When the thickness of the protective layer is less than 100nm, the active layer may be easily damaged, and when the thickness of the protective layer is greater than 300nm, the permeation flux and the salt rejection rate of the separation membrane may be reduced.
An exemplary embodiment of the present specification provides a separation membrane manufactured by the above-described method for manufacturing a separation membrane, wherein the aqueous MgSO at 2,000ppm4A salt rejection of 99.7% or greater, and a permeate flux of 21GFD or greater, measured at conditions of solution, pressure of 130psi, temperature of 25 ℃, and 4L/min.
The salt rejection is preferably 99.7% to 99.9%, and more preferably 99.77% to 99.85%.
The permeate flux is preferably 21 to 29GFD, and more preferably 21.16 to 25.85 GFD.
When the separation membrane according to the present specification satisfies the above-described salt rejection rate and permeation flux, the separation membrane can be easily used for separating sulfate ions (SO) in seawater4 2-)。
In this specification, GFD is the unit of permeate flux and means gallons per ft2The day is.
An exemplary embodiment of the present specification provides a separation membrane manufactured by the above-described method for manufacturing a separation membrane, wherein the separation membrane satisfies the following formula 1.
[ equation 1]
0.28≤Aa/Ab≤0.50
In the formula 1, the first and second groups of the compound,
aa means at 1640cm during FT-IR analysis-1An absorbance value at a wavenumber of, and
ab means at 1587cm during FT-IR analysis-1The wavenumber of (2) is used.
Specifically, the spectrum may be measured using Cary 660 during FT-IR analysis, but the measurement method is not limited thereto.
In one exemplary embodiment of the present specification, preferably, 0.31. ltoreq. Aa/Ab. ltoreq.0.49, and more preferably, 0.32. ltoreq. Aa/Ab. ltoreq.0.48.
1800cm when analyzed during FT-IR analysis of a separation membrane produced by the above-described method for producing a separation membrane-1To 1000cm-1In the wave number range of (b), the ratio of the thickness of the active layer to the thickness of the porous layer included in the separation membrane may be determined according to the content ratio of the sulfone group and the amide group contained in the separation membrane. The polysulfone of the porous layer contains sulfone groups, and the polyamide of the active layer contains amide groups.
When the Aa/Ab value of formula 1 satisfies the range of 0.28. ltoreq. Aa/Ab. ltoreq.0.50, the thickness of the active layer manufactured by interfacial polymerization of the composition for forming the active layer and the organic solution containing the acid halide compound as described above is as small as compared with the thickness of the porous layer to the extent that the salt rejection and the permeation flux of the separation membrane expected in the present specification can be satisfied. When the value of Aa/Ab is less than 0.28, the thickness of the active layer is so small that the salt rejection rate of the separation membrane including the active layer rapidly decreases, and when the value of Aa/Ab is greater than 0.50, the thickness of the active layer is so large that the permeation flux of the separation layer including the active layer decreases.
In an exemplary embodiment of the present specification, the separation membrane may be a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane, or a reverse osmosis membrane. Preferably, the separation membrane may be a nanofiltration membrane.
An exemplary embodiment of the present specification provides a water treatment module comprising one or more of the separation membranes.
The number of reverse osmosis membranes included in the water treatment module may be 1 to 50, 1 to 30, and preferably 24 to 28, but is not limited thereto.
The specific kind of the water treatment module is not particularly limited, and examples thereof include a plate-and-frame module, a tube module, a hollow fiber module, or a spiral wound module, etc.
In addition, other configurations, manufacturing methods thereof, and the like are not particularly limited as long as the water treatment module of the present invention includes the above-described separation membrane, and general means known in the art may be employed without limitation.
Fig. 1 shows a separation membrane according to an exemplary embodiment of the present description. In particular, fig. 1 shows such a separation membrane: wherein a porous layer comprising a first porous support 100 and a second porous support 200 are sequentially disposed; and an active layer 300 into which the saline water 400 flows such that the purified water 500 is released to pass through the support body 100 and the concentrated water 600 is released to the outside without passing through the active layer 300.
FIG. 2 illustrates a water treatment module according to an exemplary embodiment of the present description. Specifically, the water treatment module is configured to include a central tube 40, a feed spacer 20, a separation membrane 10, a warp knit (tricot) filtration channel 30, and the like. When raw water flows through the water treatment module, the raw water flows in through the feed spacer 20 in the water treatment module. One or more separation membranes 10 extend outwardly from the tube 40 and are wrapped around the tube 40. The feed spacer 20 forms such a passage through which raw water flows from the outside and serves to maintain the distance between one separation membrane 10 and the other separation membrane 10. For this purpose, the feed spacer 20 is in contact with one or more separation membranes 10 on the upper and lower side and wound around the tube 40. The warp knit filtering channel 30 generally has a structure in the form of a woven fabric, and serves as a channel for creating a space for enabling purified water to flow through the separation membrane 10. The tube 4 is located in the center of the water treatment module and serves as a passage for filtered water to flow in and out. In this case, since it is preferable to form a hole having a predetermined size on the outer side of the tube 40 so that the filtered water flows in, it is preferable to form one or more holes. When the separation membrane 10 includes the active layer 300 manufactured by the composition for forming an active layer, the performance of the separation membrane in terms of salt rejection and/or flux may be improved.
Detailed Description
Hereinafter, the present specification will be described in detail with reference to examples for specifically describing the present specification. However, the embodiments according to the present specification may be modified in various forms, and should not be construed that the scope of the present specification is limited to the embodiments described in detail below. The embodiments of the present description are provided to more fully explain the present description to those of ordinary skill in the art.
Preparation example
Example 1.
(production of porous layer)
As the first porous support, a nonwoven fabric was used, the nonwoven fabric was polyethylene terephthalate, and polyethylene terephthalate having a thickness of 100 μm was used.
A polymer solution comprising polysulfone is prepared to produce a polysulfone layer on a first porous support that is a second porous support. The polymer solution comprising polysulfone is a homogeneous liquid phase obtained after: 15 wt% of polysulfone solids, based on the total weight of the polymer solution comprising polysulfone, was placed in 85 wt% of solvent dimethylformamide and the resulting mixture was dissolved at 80 ℃ to 85 ℃ for 12 hours.
After that, a second porous support (polysulfone layer) was produced by casting a polymer solution containing polysulfone on the first porous support (polyethylene terephthalate) at 40 μm by a slit die coating method. By doing so, a porous layer including a support and a polysulfone layer was produced.
(production of active layer)
To fabricate an active layer on a porous layer, a composition for forming the active layer is prepared. 0.11 wt% of 4,4' -bipiperidine, which is a compound represented by chemical formula 1, and 0.25 wt% of piperazine, which is a compound represented by chemical formula 2, are put into the composition for forming an active layer, based on the total weight of the composition for forming an active layer, 6 wt% of triethylamine/camphorsulfonic acid is added thereto in the form of a salt, and sodium hydroxide (NaOH) is added thereto to adjust the pH of the composition for forming an active layer to 12.5.
Further, in order to uniformly apply the composition for forming an active layer on the surface of the porous layer, a surfactant of Sodium Lauryl Sulfate (SLS) and a hydrophilic polymer compound of polyvinyl alcohol were added thereto in amounts of 0.5 wt% and 0.5 wt%, respectively, based on the total weight of the composition for forming an active layer. Further, the composition for forming the active layer is prepared by including the remaining portion of water.
Thereafter, an aqueous solution layer is formed by applying the prepared composition for forming an active layer on the porous layer. In addition, additional aqueous solution generated during application is removed by using an air knife.
An organic solution containing an acid halide compound is applied on the aqueous solution layer. The organic solution containing the acid halide compound is prepared by including 0.45 wt% of trimesoyl chloride (TMC) and the remaining portion of the organic solvent (IsoPar G), based on the total weight of the organic solution containing the acid halide compound.
Then, a separation membrane was manufactured by drying the liquid-phase components in an oven at 95 ℃ until all the liquid-phase components were evaporated, and then washing the residue with ultra pure water (DIW).
After applying an aqueous polyvinyl alcohol solution as a composition for forming a protective layer on the surface of the washed separation membrane, a final separation membrane was manufactured by removing additional aqueous solution using an air knife and drying the liquid phase compound at 85 ℃ until all liquid phase components were evaporated. The composition for forming a protective layer was prepared by including 3 wt% of polyvinyl alcohol and the remaining portion of water, based on the total weight of the composition for forming a protective layer.
Examples 2 to 4
A separation membrane was manufactured in the same manner as in example 1, except that those described in table 1 below were applied to example 1 as contents of each of the compound represented by chemical formula 1 and the compound represented by chemical formula 2 contained in the composition for forming an active layer.
Comparative examples 1 to 5
A separation membrane was manufactured in the same manner as in example 1, except that those described in table 1 below were applied to example 1 as contents of each of the compound represented by chemical formula 1 and the compound represented by chemical formula 2 contained in the composition for forming an active layer.
Comparative examples 6 to 9
A separation membrane was manufactured in the same manner as in example 1, except that those described in table 1 below were applied to example 1 as the contents of each of the compound represented by chemical formula 1 and the compound represented by chemical formula 2 contained in the composition for forming an active layer, and the pH of the composition was adjusted to 10 by not adding sodium hydroxide thereto in example 1.
[ Table 1]
Examples of the experiments
(measurement of Performance of separation Membrane)
Measurement of salt rejection and permeate flux
Determined by using 2,000ppm of aqueous MgSO 4L/min at 130psi4After the solution was subjected to the plant operation for about 1 hour to stabilize the separation membranes manufactured in examples 1 to 4 and comparative examples 1 to 9, the permeation flux (gallons/ft) was calculated by measuring the amount of water permeated at 25 ℃ for 10 minutes2Day (GFD)) and the results of calculating the salt rejection by analyzing the salt concentration before and after permeation using a conductivity meter are shown in table 2 below.
[ Table 2]
Salt rejection (%)
Permeate flux (GFD)
Example 1
99.77
21.16
Example 2
99.81
25.85
Example 3
99.85
24.46
Example 4
99.84
25.14
Comparative example 1
99.95
16.61
Comparative example 2
99.87
13.21
Comparative example 3
99.83
14.41
Comparative example 4
98.81
32.44
Comparative example 5
97.75
53.27
Comparative example 6
75.89
17.65
Comparative example 7
79.14
18.21
Comparative example 8
74.95
16.58
Comparative example 9
73.51
18.39
From table 2, it can be determined that the separation membranes in examples 1 to 4 have a permeate flux of 21GFD or more while maintaining a salt rejection of 99.7% or more as compared with the separation membranes in comparative examples 1 to 9.
From this, it was confirmed that the separation membrane according to the present specification had excellent performance.
(measurement of thickness of active layer by FT-IR analysis)
Among the separation membranes manufactured by examples 1 to 4 and comparative examples 1 to 5, 1800cm was analyzed using Cary 660 as an FT-IR spectrometer-1To 1000cm-1The wavenumber interval of (2). Specifically, the measurement is at 1640cm-1Is measured at a wavenumber of (2), and is described as Aa in Table 3 below, and is measured at 1587cm-1And is described as Ab in table 3 below. In addition, the value of Aa/Ab was calculated and described in Table 3 below.
[ Table 3]
Aa
Ab
Aa/Ab
Example 1
0.172
0.36
0.48
Example 2
0.140
0.36
0.39
Example 3
0.124
0.36
0.34
Example 4
0.114
0.36
0.32
Comparative example 1
0.186
0.36
0.52
Comparative example 2
0.184
0.36
0.51
Comparative example 3
0.183
0.36
0.51
Comparative example 4
0.096
0.36
0.27
Comparative example 5
0.087
0.36
0.24
From table 3, it can be confirmed that the Aa/Ab value in examples 1 to 4 satisfies 0.28 ≦ Aa/Ab ≦ 0.50, and thus the thickness of the active layer manufactured by interfacial polymerization of the composition for forming the active layer and the organic solution containing the acid halide compound as described above is so small as to satisfy the salt rejection and the permeation flux of the separation membrane expected in the present specification, compared to the thickness of the porous layer.
Although preferred exemplary embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made and implemented within the scope of the claims and the detailed description of the present invention, and this also falls within the scope of the present invention.
[ description of reference numerals ]
10: separation membrane
20: feed spacer
30: warp knitted fabric filtration channel
40: pipe
100: a first porous support
200: a second porous support
300: active layer
400: salt water
500: purified water
600: concentrated water
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