KR20140073010A - Pressure Retarded osmosis membrane with enhanced Pressure Resistant and Manufacturing method - Google Patents

Abstract

The present invention relates to a pressure retarded osmosis membrane with an enhanced pressure resistance, and a manufacturing method thereof. The manufacturing method of a pressure retarded osmosis membrane according to the present invention has advantage of satisfying the high flux requirement while maintaining an enhanced pressure resistance. Furthermore, the pressure retarded osmosis membrane of the present invention can achieve a high salt exclusion rate, and can prevent the solute of an inducing solution from reverse diffusing toward the reverse osmosis direction. The pressure retarded osmosis membrane manufactured by the manufacturing method of the present invention can provide a high flux and the power density.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-retarded osmotic membrane having excellent pressure resistance,

TECHNICAL FIELD The present invention relates to a pressure-sensitive delayed osmotic membrane having excellent pressure resistance, and more particularly, to a pressure-delayed osmotic membrane having excellent pressure resistance capable of providing a high flow rate and power density, and a method of manufacturing the same.

Pressure retarded osmosis (PRO) is an osmotic pressure generated by a salinity difference by installing a membrane at the point where seawater and fresh water meet. Fresh water and brine (salt water), which have different salt gradients, The osmosis increases the saline-side pressure head (the voltage corresponding to the turbine effective head of ~ 120 m), which is the mechanical energy of the turbine runner To produce power.

This osmotic power generation method starts from the concept that a membrane is installed at the point where seawater and fresh water meet, and produces osmotic pressure generated by salinity difference.

In other words, the pressure delay osmosis is a phenomenon in which the permeation of water in the osmotic direction is delayed by applying a pressure lower than the osmotic pressure to the opposite direction of the osmosis phenomenon generated through the membrane in the solution having different salinity, System.

Such an osmotic power generation method is a renewable energy field that can be applied to a boundary region where river water and sea water meet. In particular, an osmotic power plant can provide a continuous electricity supply source under any weather condition unlike wind, wave and solar energy In terms of value, there is endless use.

However, the prior art is a report on equipment and maintenance using pressure delay osmosis, and there has been no report on a suitable dedicated membrane for pressure-delayed osmosis power generation, and conventional pressure-delayed osmosis membranes maintain pressure resistance And at the same time the high flow rate can not be met.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a pressure-sensitive delayed osmosis membrane having excellent pressure resistance and excellent pressure resistance, .

In order to solve the above problems, the present invention provides a pressure-sensitive delayed osmosis membrane having pressure resistance at a pressure of 10 kg / cm ² , comprising: a nonwoven fabric layer; a polyacrylic polymer supporting layer formed on the nonwoven fabric layer; And a polyamide-based active layer formed on the polymer support layer.

According to a preferred embodiment of the present invention, the nonwoven fabric layer may have an air permeation rate of 2 to 20 cc / cm2sec, and the nonwoven fabric layer may have a thickness of 80 to 150 mu m.

According to a preferred embodiment of the present invention, the polyacrylic polymer supporting layer has a pore structure of 50 to 80% and a pore structure of 20 to 50% in the form of sponges, And the polyacrylic polymer support layer may be at least one selected from the group consisting of polyacrylates, polyacrylamides, and polyacrylonitriles, and the thickness of the polyacrylic polymer support layer is from 30 to 250 Lt; / RTI >

According to one preferred embodiment of the present invention, the size of the delayed pressure osmosis membrane 26cm ² one time, 10 kg / cm ² pressure during the induction solution 35,000ppm water flow measurement using the conditions, the power density of the separator 0.58 ~ It is possible to provide a pressure-delayed osmosis membrane of 2.14 W / m ² .

Another aspect of the present invention relates to a method for producing a polyacrylic polymer, comprising the steps of: (1) casting a polyacrylic polymer-containing solution on a nonwoven fabric; (2) immersing the non-solvent in a coagulation bath containing 0.01 to 10% of solvent to form a hydrophobic polymer support layer by phase transition; And (3) forming a polyamide layer on the surface of the hydrophobic polymer support layer by interfacial polymerization between an aqueous solution containing a polyfunctional amine and an organic solution containing a polyfunctional acid halide compound; And a pressure-sensitive adhesive layer.

According to a preferred embodiment of the present invention, the polymer-containing solution of the step (1) may include at least one selected from the group consisting of polyacrylate, polyacrylamide and polyacrylonitrile, May be any one selected from the group consisting of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide, and the temperature in the coagulation bath of step (2) Lt; 0 > C.

Further, the hydrophobic polymer in which 50 to 80% of the pore structure of the sponge type and 20 to 50% of the pore structure of the finger type are regularly or irregularly arranged by the phase transition in the step (2)

A support layer can be formed.

The pressure-sensitive osmotic membrane having excellent pressure resistance of the present invention satisfies the requirements of high flow rate while maintaining the pressure resistance, and achieves a high salt rejection rate as well as a pressure delay with excellent pressure resistance capable of providing a high flow rate and power density An osmotic membrane and a method for producing the same.

1 is a cross-sectional view of a pressure-delayed osmosis membrane according to an embodiment of the present invention.
FIG. 2 is an electron micrograph of a pressure-delayed osmotic membrane prepared according to Example 1 of the present invention. FIG.
3 is an electron micrograph of a pressure-delayed osmotic membrane produced according to Example 2 of the present invention.
4 is an electron micrograph of the pressure-delayed osmotic membrane prepared according to Example 3 of the present invention.
5 is an electron micrograph of the composite membrane produced by Comparative Example 1 of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail with reference to the accompanying drawings.

As described above, there is no report on a suitable dedicated membrane for pressure-delayed osmosis power generation, which is merely a report on equipment and maintenance using pressure delay osmosis. In addition, The high flow rate can not be satisfied at the same time.

According to an aspect of the present invention, there is provided a pressure-sensitive delayed osmosis membrane having pressure resistance at a pressure of 10 kg / cm ² , comprising: a nonwoven fabric layer; A polyacrylic polymer support layer formed on the nonwoven fabric layer; And a composite membrane in which a polyamide-based active layer formed on the polymer support layer is laminated. The present invention has been made to solve the above-mentioned problems. Accordingly, the pressure-sensitive osmotic membrane having excellent pressure resistance of the present invention can provide a pressure-sensitive osmotic membrane having excellent pressure resistance that meets high flow rate requirements while maintaining pressure resistance, and a method for manufacturing the same.

1 is a cross-sectional view of a pressure-delayed osmosis membrane according to an embodiment of the present invention. The pressure delayed osmosis membrane 100 is formed by forming a polyacrylic polymer supporting layer 102 on a nonwoven fabric layer 103 and forming a composite membrane 101 in which the polyamide active layer is laminated on the acrylic polymer supporting layer 102 do.

First, the nonwoven fabric layer 103 will be described.

In the pressure-sensitive osmosis membrane of the present invention, the nonwoven fabric layer plays a role of smoothly flowing water by supporting the membrane and high hydrophilicity of the nonwoven fabric.

Preferred materials that may be used in the nonwoven fabric layer of the present invention include synthetic fibers selected from the group consisting of polyester, polypropylene, nylon, and polyethylene; Or cellulose-based pulp may be used. The nonwoven fabric layer can control the physical properties of the membrane according to porosity and hydrophilicity of the material.

The non-woven fabric layer may have an average pore size of 1 to 600 μm, preferably 5 to 300 μm, so that smooth permeation of water and water permeability required for the pressure delayed osmosis membrane can be improved.

The thickness of the nonwoven fabric layer of the present invention may be in the range of 80 to 150 탆. If the thickness is less than 80 탆, the strength and support of the entire membrane are insufficient.

Next, the polyacrylic polymer supporting layer 102 will be described.

In the pressure delayed osmosis membrane of the present invention, the polymer support layer plays a role of securing a high flow rate due to the porous structure. Heat resistance and strength

According to a preferred embodiment of the present invention, the polyacrylic polymer support layer may be formed from a solution containing at least one selected from the group consisting of polyacrylate, polyacrylamide and polyacrylonitrile, Can be formed into polyacrylonitrile.

The thickness of the polyacrylic polymer support layer may be 30 to 250 占 퐉. If the thickness is less than 30 占 퐉, maintaining the pressure resistance of the entire membrane may be insufficient. If the thickness is more than 250 占 퐉, the flow rate may be decreased.

The polyacrylic polymer support layer of the present invention may have a sponge-like pore structure of 50 to 80% and a finger-like pore structure of 20 to 50% arranged regularly or irregularly with respect to the membrane area. 2 to 4)

 At this time, if the pore structure of the finger type is less than 20%, the permeation flow rate is remarkably decreased, and if the pore structure of the finger type is formed by more than 50%, the pressure resistance is maintained,

Performance is not ensured.

Next, the polyamide layer 101 will be described.

In the pressure-sensitive osmotic membrane of the present invention, the polyamide layer is formed on the polyacrylic polymer support layer by interfacial polymerization between an aqueous solution containing a polyfunctional amine and an organic solution containing a polyfunctional acid halide compound.

With the polyamide layer of the present invention, the pressure-sensitive osmotic membrane of the present invention plays a role of securing a high salt rejection rate which can remove univalent ions which are difficult to remove in a single membrane structure. Furthermore, since the physical properties required for the positive osmosis method are optimized, it is suitable for accommodating a high concentration of seawater.

More specifically, the formation of the polyamide layer is carried out by adding an aqueous solution containing a polyfunctional amine selected from metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, piperazine or alkylated piperidine and an alkylated aliphatic amine, Is carried out by interfacial polymerization between the compounds by contacting an organic solution containing a polyfunctional acid halide compound selected from a functional acyl halide, a polyfunctional sulfonyl halide or a polyfunctional isocyanate.

At least one hydrophilic functional group selected from the group consisting of a hydroxyl group, a sulfonate group, a carbonyl group, a trialkoxysilane group, an anion group and a tertiary amino group is added to an aqueous solution containing the polyfunctional amine- or alkylated aliphatic amine A hydrophilic compound, i.e., a hydrophilic amino compound, may be further added.

More specifically, preferred examples of the hydrophilic compound having a hydroxy group include 1,3-diamino-2-propanol, ethanolamine, diethanolamine, 3-amino-1-propanol, , 2-amino-1-butanol.

The hydrophilic compound having a carbonyl group is selected from the group consisting of aminoacetaldehyde dimethylacetal,? -Aminobutylolactone, 3-aminobenzamide, 4-aminobenzamide and N- (3-aminopropyl) -2-pyrrolidinone do.

Further, as the hydrophilic compound containing a trialkoxysilane group, (3-aminopropyl) triethoxysilane or (3-aminopropyl) trimethoxysilane is preferably used.

Examples of the hydrophilic compound having an anionic group include glycine, taurine, 3-amino-1-propylselphenic acid, 4-amino-1-butenesulfonic acid, 2-aminoethylhydrogensulphate, 3-aminobenzenesulfonic acid , 3-amino-4-hydroxybenzenesulfonic acid, 4-aminobenzenesulfonic acid, 3-aminopropylphosphonic acid, 3-amino-4-hydroxybenzoic acid, Aminobutane oxidase, 4-amino-2-hydroxybutyric acid, 4-aminobutyric acid, and glutamic acid are selected from the group consisting of benzoic acid, benzoic acid, benzoic acid,

Examples of the hydrophilic compound having one or more tertiary amino groups include 3- (dimethylamino) propylamine, 3- (diethylamino) propylamine, 4- (2-aminoethyl) Aminoethyl) piperazine, 3,3'-diamino-N-methyldipropylamine and 1- (3-aminopropyl) imidazole.

Accordingly, the polyamide layer of the present invention can be formed as a dense surface layer of a pressure-delayed osmosis membrane to form a structure resistant to pressure resistance, and at the same time, the thin film type active layer maintains pores of uniform size to secure chemical resistance and high salt rejection rate can do.

From the above composite membrane structure design, the pressure-delayed osmotic membrane of the present invention has a power density of 0.58 to 2.14 W / m ² when measuring the flow rate of water using 35,000 ppm of the induction solution under the pressure of 10 kg / (See Table 1). ≪ tb >< TABLE >

According to another aspect of the present invention, there is provided a method of manufacturing a non-woven fabric, comprising the steps of: (1) applying a polyacrylic polymer- (2) immersing the non-solvent in a coagulation bath containing 0.01 to 10% of solvent to form a hydrophobic polymer support layer by phase transition; And (3) forming a polyamide layer on the surface of the hydrophobic polymer support layer by interfacial polymerization between an aqueous solution containing a polyfunctional amine and an organic solution containing a polyfunctional acid halide compound; And a pressure-sensitive adhesive layer.

First, the step (1) may be performed by applying a polyacrylic polymer-containing solution onto the nonwoven fabric. The polymer-containing solution in the step (1) may include at least one selected from the group consisting of polyacrylate, polyacrylamide and polyacrylonitrile, and preferably polyacrylonitrile.

The solvent of the polymer-containing solution may be any of conventionally usable solvents, and preferred examples thereof include dimethylformamide, N-methyl-2-pyrrolidone, Dimethylacetamide, dimethylsulfoxide, and most preferably, dimethylforamide. The polymer may be used in an amount of 0.1 to 20% by weight based on 100% by weight of the polymer-containing solution. .

The next step (2) is a step of forming a polymer supporting layer by phase transition, and may contain 0.01 to 10% by weight of a solvent in the non-solvent used in the coagulation bath.

At this time, the solvent to be used is any one selected from the group consisting of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide, and the dimethylacetamide or dimethylformamide of the present invention is used However, the present invention is not limited thereto, as long as it satisfies the requirement to control the exchange rate of the solvent contained in the polymer solution.

Also, the non-solvent may include distilled water; Or an alcohol selected from methanol or ethanol. When the content of the solvent is less than 0.01% by weight, the effect of improving the porosity is insufficient. When the content of the solvent is more than 10% by weight, the ratio of the solvent to the non- , Which is not preferable because of difficulty in preparation of the film and control of the optimum porosity.

In addition, the phase transition can be promoted by keeping the temperature in the coagulation bath in the step (2) at 40 to 80 캜. At this time, if the temperature is lower than 40 캜, there may be a problem that the pore structure of the separation membrane is difficult to control If it exceeds 80 캜, the film may be damaged due to shrinkage or the like.

The hydrophobic polymer support layer may be formed in which the sponge-type pore structure 50 to 80% and the finger-type pore structure 20 to 50% are regularly or irregularly arranged by the phase transition in the step (2).

At this time, if the pore structure of the finger type is less than 20%, the permeation flux is remarkably decreased, and if the pore structure of the finger type is formed by more than 50%, the pressure resistance is maintained but high flow rate performance is not ensured.

The thickness of the hydrophobic polymer support layer is preferably as small as possible in order to increase the flow rate. To satisfy such a requirement, the hydrophobic polymer support layer of the present invention has a thickness of 30 to 250 탆.

Next, in step (3) of the production method of the present invention, a polyamide layer may be formed on the hydrophobic polymeric support layer. Wherein the polyamide layer is formed by adding a polyfunctional acyl halide, a polyfunctional amine, and a polyfunctional amine to an aqueous solution containing a polyfunctional amine and an alkylated aliphatic amine selected from metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, piperazine or alkylated phe- A sulfonyl halide, or a polyfunctional isocyanate in the presence of an organic solvent containing a polyfunctional acid halide compound. At least one hydrophilic functional group selected from the group consisting of a hydroxyl group, a sulfonate group, a carbonyl group, a trialkoxysilane group, an anion group and a tertiary amino group is added to an aqueous solution containing the polyfunctional amine- or alkylated aliphatic amine A hydrophilic compound, i.e., a hydrophilic amino compound, may be further added.

Thus, the pressure-sensitive osmotic membrane produced by the production method of the present invention has stain and chemical resistance. In addition, although the single membrane structure has a large pore size, it is difficult to remove a small salt such as monovalent ions, but the membrane of the composite membrane structure of the present invention having a polyamide layer can remove monovalent ions. That is, it is possible to achieve a high salt rejection rate and to prevent the dissolution of the solute in the induction solution in the reverse osmosis direction.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The present invention is intended to more specifically illustrate the present invention, and the scope of the present invention is not limited to these embodiments.

[ Example ]

Example  One

A polymer solution composed of 14% polyacrylonitrile and 86% dimethylformamide was cast on a nonwoven fabric having porosity of 6.3 cc / cm 2 · sec air permeability prepared by a papermaking method to a thickness of 150 탆 10% . Immediately, the impregnant was immersed in a coagulation bath containing 1% by weight of a dimethylformamide (DMF) solvent to conduct phase transformation to form a polymeric support layer made of polyacrylonitrile. At this time, the temperature of the coagulation bath solution was maintained at 60 캜.

After immersing and phase transitions, the polymer support layer formed of polyacrylonitrile was stored in ultrapure water for one day to extract the solvent. The obtained polymer support layer has a pore structure of a finger shape.

Thereafter, the polymer layer was immersed in an aqueous solution containing 2% by weight of metaphenylenediamine (MPD) for 1 minute on the surface of the polymer layer composed of polyacrylonitrile from which the solvent was extracted, and then the water layer on the surface was removed by a pressing method. Thereafter, the mixture was immersed in an ISOPAR solvent (Exxon Corp.) in an organic solution containing 0.1% by weight of trimethoyl chloride (TMC) for 1 minute and subjected to interfacial polymerization, followed by natural drying at room temperature (25 ° C) for 1 minute and 30 seconds, . Thereafter, a pressure delayed osmosis membrane was prepared by immersing in a 0.2 wt% sodium carbonate solution for 2 hours to remove unreacted residues.

Example  2

To the non-solvent of the coagulation bath was added 3% by weight of dimethylformamide (DMF)

The pressure-sensitive osmosis membrane was prepared in the same manner as in Example 1, except that

Example  3

The procedure of Example 1 was repeated to prepare a polymer support layer using a polymer solution prepared by mixing 12 wt% of polyacrylonitrile with 88 wt% of dimethyl formamide (DMF) An osmotic membrane was prepared

Example  4

A pressure delayed osmotic membrane was prepared in the same manner as in Example 1 except that polyacrylonitrile was used instead of polyacrylonitrile.

Comparative Example  One

The temperature of the coagulation bath solution was maintained at room temperature and immersed in the non-coagulating water of the coagulation bath

The pressure-sensitive osmosis membrane was prepared in the same manner as in Example 1, except that the polymer support layer was formed.

Comparative Example  2

A pressure delayed osmosis membrane was prepared in the same manner as in Example 1, except that polyaniline was used instead of polyacrylonitrile.

Experimental Example  One

In order to evaluate the membrane performance of the composite membranes prepared in Examples 1 to 3 and Comparative Example 1, the composite membrane was mounted in the direction in which the active layer of the membrane was directed to the induction solution (in the direction of pressure) , Distilled water) at high salinity (inducing solution 35,000 ppm NaCl). At this time, the amount of water movement in the pressure delayed osmosis process was measured by using distilled water of raw water and 35,000 ppm of the induction solution under a pressure condition of 10 kg / cm ² , and the flow rate of the pressure delayed osmosis membrane was confirmed by converting the amount of water into power density.

The performance of the pressure-delayed osmosis process is expressed in terms of power density, and the current density has units of power per unit area (W / m 2). The power density was calculated from the following equation (1) by applying the flow rate (gfd) and the pressure obtained from the performance evaluation of the pressure delay osmosis membrane and the results are shown in Table 1 below.

[Equation 1]

(단, W는 전력밀도, JW는 유량, △P는 압력이다.)

(Where W is the power density, JW is the flow rate, and DELTA P is the pressure).

division Pressure level [kg / cm ² ] Flow rate [gfd] Power density [W / m ² ] Example 1 ~ 10 4.62 2.14 Example 2 ~ 10 3.46 1.60 Example 3 ~ 10 3.01 1.39 Example 4 ~ 10 3.36 1.55 Comparative Example 1 ~ 10 1.43 0.66 Comparative Example 2 ~ 5 2.52 0.58

As a result of the measurement, as shown in Table 1, when the pressure-delayed osmosis membrane was measured under the pressure of 10 kg / cm ² , the flow rate of water in the pressure delay osmosis process was measured using distilled water of the raw water and 35,000 ppm of the induction solution. Examples 1 to 4 having a high flow rate performance can be used while maintaining the pressure resistance, and the best embodiment is applicable as the pressure-delayed osmosis membrane. On the other hand, although the pressure resistance was confirmed under the pressure of 10 kg / cm ^{2 in the} case of the recovered membrane of Comparative Example 1, the pore structure of the polymer support layer was confirmed to be low, but the flow rate and power density were low.

Experimental Example  2

The pressure-delayed osmotic membranes prepared in Examples 1 to 4 and Comparative Example 1 were confirmed by scanning electron microscopy (SEC, SNE-3000M), and the results are described with reference to FIGS. 2 to 5.

FIG. 2 is a scanning electron microscope photograph of the pressure-delayed osmotic membrane prepared in Example 1. FIG. 2 is a structure in which the obtained polymer support layer has a structure in which a pore structure of a sponge type and a pore structure of a finger type are complexly formed, It is 45% of the structure.

FIG. 3 is a scanning electron microscope (SEM) image of the pressure-delayed osmotic membrane prepared in Example 2, and the obtained polymer support layer has a finger type ratio of 37.5% of the total structure.

FIG. 4 is a scanning electron micrograph of the pressure delayed osmotic membrane prepared in Example 3, wherein the polymeric support layer has a finger type ratio of 30% of the total structure.

FIG. 5 is a pressure-delayed osmosis membrane prepared in Comparative Example 1, and the obtained polymer support layer is a complete sponge-like pore structure.

100: pressure delayed osmosis membrane 101: polyamide layer
102: polymer supporting layer 103: nonwoven fabric layer

Claims (12)

In the pressure delayed osmosis membrane having pressure resistance secured under a pressure of 10 kg / cm ² ,
A nonwoven fabric layer;
A polyacrylic polymer support layer formed on the nonwoven fabric layer; And
And a polyamide-based active layer formed on the polymer support layer.
The method according to claim 1,
Wherein the nonwoven fabric layer has an air permeation amount of 2 to 20 cc / cm < 2 > sec.
The method according to claim 1,
Wherein the non-woven fabric layer has a thickness of 80 to 150 mu m.
The method according to claim 1,
Characterized in that the polyacrylic polymer support layer has a regular or irregular arrangement of 50 to 80% of sponge-like pore structure and 20 to 50% of pore structure of finger shape compared to the membrane area. Membrane.
The method according to claim 1,
Wherein the polyacrylic polymer support layer is at least one selected from the group consisting of polyacrylate, polyacrylamide, and polyacrylonitrile.
The method according to claim 1,
Wherein the polyacrylic polymer support layer has a thickness of 30 to 250 占 퐉.
The method according to claim 1,
When the size of the pressure delay osmosis membrane is 26 cm ² ,
10 kg / cm ² When the flow rate of water is measured using 35,000 ppm of the induction solution under the pressurized condition,
Wherein the separation membrane has a power density of 0.58 to 2.14 W / m ² .
(1) applying and casting a polyacrylic polymer-containing solution onto a nonwoven fabric;
(2) immersing the non-solvent in a coagulation bath containing 0.01 to 10% of solvent to form a hydrophobic polymer support layer by phase transition; And
(3) forming a polyamide layer on the surface of the hydrophobic polymer support layer by interfacial polymerization between an aqueous solution containing a polyfunctional amine and an organic solution containing a polyfunctional acid halide compound; Wherein the pressure-relief osmotic membrane separation membrane comprises:
9. The method of claim 8,
Wherein the polymer-containing solution in step (1) comprises at least one selected from the group consisting of polyacrylates, polyacrylamides, and polyacrylonitriles.
9. The method of claim 8,
Wherein the solvent of step (2) is at least one selected from the group consisting of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, and dimethylsulfoxide.
9. The method of claim 8,
Wherein the temperature in the coagulation bath in step (2) is maintained at 40 to 80 占 폚.
12. The method of claim 11,
Characterized in that a hydrophobic polymer support layer is formed in which the sponge-like pore structure of 50 to 80% and the finger-shaped pore structure of 20 to 50% are regularly or irregularly arranged by the phase transition of step (2) .

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