JP3536501B2 - Method and apparatus for producing composite semipermeable membrane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a high-performance semipermeable composite membrane for selectively permeating and separating components of a liquid mixture. The semipermeable composite membrane obtained by the present invention can be used particularly for desalination of can water, desalination of seawater, and production of ultrapure water used for production of semiconductors. Furthermore, it is possible to selectively remove or recover contaminants or useful substances contained therein from dyeing wastewater, electrodeposition paint wastewater, and the like, thereby contributing to closed wastewater.

More specifically, the present invention relates to a method and an apparatus for producing a crosslinked polyamide composite membrane suitable for producing ultrapure water, desalting can water or seawater, removing harmful substances, collecting useful substances, treating wastewater, and the like. .

[0003]

2. Description of the Related Art With respect to the separation of a mixture, there are various techniques for removing substances (eg, salts) dissolved in a solvent (eg, water). In recent years, membrane separation has been used as a process for saving energy and resources. The law has been used. Microfiltration (MF; Micro)
Filtration method, ultrafiltration (UF; Ultr)
afiltration method, reverse osmosis (RO; Rev)
rs Osmosis) method. More recently, a membrane separation (Loose R) located between reverse osmosis and ultrafiltration
A membrane separation method of the concept of O or NF (Nanofiltration) has appeared and has been used. For example, the reverse osmosis method is used for desalinating seawater or low-concentration saline water (canned water) to provide industrial, agricultural, or domestic water. According to the reverse osmosis method, desalinated water can be produced by permeating water containing salt through a reverse osmosis membrane at a pressure higher than the osmotic pressure. This technology can be used, for example, to obtain drinking water from seawater, can water, and water containing harmful substances, and has also been used in the production of industrial ultrapure water, wastewater treatment, and recovery of valuable resources. Was.

Conventionally, as a semipermeable membrane used industrially, there has been an asymmetric membrane type cellulose acetate membrane (for example, US Pat. Nos. 3,133,132 and 3,133).
137). This is a membrane originally developed by Loeb and Sourirajan ("Sea Water Deminer").
alias by means of an
Osmotic Membrane ", in Adv
ances in Chemistry Series
# 38, American Chem. So
c. , Washington DC. C. (196
3)). This membrane had the advantages of excellent basic performance and easy manufacturing at that time, but in order to obtain more pure water at a lower pressure, it was necessary to reduce the salt rejection rate and the amount of fresh water. The surface was not enough. In addition, microorganisms are easily generated on the membrane surface, and the membrane is deteriorated by the microorganisms, and the membrane is easily deteriorated by hydrolysis. For this reason, the cellulose acetate asymmetric membrane is used for some applications, but has not been put to practical use in a wide range of applications.

[0005] To compensate for the drawbacks of the cellulose acetate membrane, a new asymmetric type reverse osmosis membrane of a synthetic polymer, for example, a reverse osmosis membrane of a linear aromatic polyamide has been proposed (for example, US Patent No. 3,567,632). Specification). These synthetic polymer asymmetric membranes were improved in terms of microbial resistance, but had the same problems in reverse osmosis performance as cellulose acetate, and a dramatic improvement in basic performance was expected. .

In order to compensate for these drawbacks, an ultra-thin film (active layer) which substantially controls the membrane separation performance is coated with a different material on a microporous support membrane as a semipermeable membrane having a different form from the asymmetric type membrane. Semipermeable composite membranes have been devised. In the case of the semipermeable composite membrane, it is possible to select the optimum material for each of the active layer and the microporous support membrane, and various membrane forming techniques can be selected.

[0007] Most of the semipermeable composite membranes currently commercially available have an active layer obtained by crosslinking a gel layer and a polymer on a microporous support membrane, and interfacial polycondensation of a monomer on the microporous support membrane. There are two types having an active layer. Specific examples of the former include JP-A-49-13282, JP-B-55-38164, and PB Report 80-18.
2090, JP-B-59-27202, 61-2
No. 7102 and the like. Specific examples of the latter include U.S. Pat. Nos. 3,744,942 and 3,926,926.
No. 798, No. 4,277,344, JP-A-55-147106, JP-A-58-24303, and JP-A-62-121603.

[0008] These semipermeable composite membranes have higher desalination performance than cellulose acetate asymmetric membranes. Furthermore, the durability of these membranes against chlorine and hydrogen peroxide used for sterilization is being improved, and the use thereof is in the stage of being spread.

However, even in these semipermeable composite membranes, there were serious defects in the manufacturing process. That is, hexane or CF is generally used as a solvent for a polymer crosslinking agent or a solvent used for interfacial polycondensation.
Solvents such as C-113 (trichlorotrifluoroethane). Hexane has a low flash point and boiling point, and it is necessary to take sufficient safety measures, such as explosion proof, when handling and storing the solution, which is a significant disadvantage in terms of economy and safety as an industrial-scale manufacturing process. It is. On the other hand, fluorocarbon (CFC, chlorofluorocarbon) solvents such as CFC-113 are considered to have been used most frequently because they have high safety and are easy to produce membranes of good performance without toxicity, but recently released into the atmosphere. The use of the specified CFCs as a causative agent of global environmental damage that destroys the ozone layer has been regarded as a problem. For this reason, UNEP
(United Nations Environment Program) calls for the Vienna Convention on the Protection of the Ozone Layer (1985) and the Montreal Protocol (1)
987), the Helsinki Declaration (1989) was adopted, and its use and production were regulated worldwide.
In 2000, a policy to completely eliminate CFCs was launched.

Under these circumstances, there has been an urgent need to develop a process and an apparatus that do not use specific CFCs in the production of composite membranes. Conventionally, in the production of composite membranes, for example, JP-B-63-36803 and U.S. Pat. No. 4,277,344 disclose m-phenylenediamine or p-phenylenediamine on the surface of a polysulfone porous support membrane. A method for obtaining a crosslinked aromatic polyamide membrane by reacting trimesic acid chloride or a mixture of trimesic acid chloride and isophthalic acid chloride is disclosed. However, the above acid chloride solution contains CFC-11.
3 or n-hexane has been used. Further, Japanese Patent Publication No. 56-500062 and U.S. Pat.
No. 9,183 and JP-A-1-130707 disclose a production method in which a similar reaction is carried out using piperazine as an amine composition.
This is a problem because FC-113 or n-hexane is used.

The solvent used in the production of these composite membranes has no or low ozone depleting ability, and it is necessary to consider the safety in handling at the same time. JP 6
2-49909 discloses a method in which polyvinyl alcohol and an amino compound such as piperazine are reacted with trimesic acid chloride to crosslink and polymerize on the surface of a polysulfone porous support membrane. Here, n-hexane, low-boiling hydrocarbon solvents represented by cyclohexane and the like are used as solvents for trimesic acid chloride as in the above-described technique, but these solvents have no ozone layer destruction ability, Many have a flash point of 0 ° C. or lower, and can be said to be extremely flammable and extremely dangerous in handling. This is particularly problematic in production on an industrial scale as described above. Further, since the solvent has a low boiling point, it is difficult to recover the solvent, and the vapor of the unrecovered solvent is released to the atmosphere as it is.

In a process for producing a composite membrane by a crosslinking reaction or an interfacial polycondensation reaction of a polymer on a porous support membrane, a crosslinking agent or a polyfunctional acid halide is brought into contact with a monomer or polymer which reacts with the crosslinking agent or a polyfunctional acid halide. Need to be removed. Conventionally, the solvent has been removed by evaporation. In particular, in the conventional composite membrane manufacturing technology, a low-boiling fluorocarbon solvent was used, so that the solvent spontaneously evaporated, and no special removal method was required. Considering that the conventional membrane formation process will not be changed even in the search and investigation of alternative solvents for specific CFCs, the method of removing the solvent in the composite membrane manufacturing process is premised on evaporation. It has not been done yet. It was thought that the boiling point of the solvent had to be low to some extent as long as the solvent was removed by natural evaporation. However, solvents having a low boiling point to a medium boiling point generally have a low flash point accordingly, and there has been a problem that it is difficult to achieve the above-mentioned safety requirements.

JP-A-59-179103 and JP-B-63-36803 disclose low-boiling solvents such as CFC-113 and n-hexane, as well as n-nonane and n-nonane, as substances suitable for acid chloride solvents. High boiling solvents such as decane are also shown. However, when a film is actually formed using these solvents, the performance disclosed in the known example can be obtained with a solvent having a low boiling point, but when a solvent having a high boiling point is used, only a membrane having a remarkably low water production amount can be obtained. There was a disadvantage that it could not be obtained.

JP-A-5-329348 discloses a method for producing a composite semipermeable membrane using a saturated hydrocarbon compound having 7 to 20 carbon atoms, and these compounds have a boiling point of 70 to 400 ° C. Nevertheless, there is only description that the range of the boiling point affects evaporation, but no specific method for removing these compounds is disclosed. Moreover, these examples show that the higher the boiling point of the compound used as the solvent, the lower the amount of fresh water.

Japanese Patent Application Laid-Open No. Hei 5-76740 discloses that a film is formed using a hydrocarbon solvent having a flash point of 10 ° C. or higher, and after the reaction is completed, a gas at a specific temperature and wind speed is blown to remove the solvent. The method is shown. However, in the method of blowing gas, it takes time to remove the solvent, the solvent is a flammable liquid, the temperature and other controls are strict, and the equipment becomes large, and the removed liquid becomes a vapor, making recovery difficult. There was a problem.

[0016]

DISCLOSURE OF THE INVENTION The present invention provides a safe, effective, and easy-to-recovery solvent using a solvent that is inexpensive and easy to handle without destroying the ozone layer. An object of the present invention is to provide a method for producing a composite semipermeable membrane.

[0017]

The present invention has the following arrangement. That is, "an aqueous solution of a water-soluble polyfunctional reagent was applied to the surface of the porous support membrane, and a solution in which a polyfunctional reagent reacting with the water-soluble polyfunctional reagent was dissolved in an organic solvent immiscible with water was applied. Thereafter, the organic solvent is removed by using two or more stages of air knives. "

In the present invention, the porous support membrane is a layer having substantially no separation performance and used for imparting strength to an ultrathin layer (active layer) having substantially separation performance. It is. The porous support membrane has an asymmetric structure with uniform fine pores or dense and fine pores on one side, and gradually larger fine pores on the other side. A structure that is 100 nm or less on the surface is preferable. The thickness of the porous support membrane is 1 μm.
m to several mm, preferably 10 μm or more from the viewpoint of film strength, and several hundred μm or less from the viewpoint of ease of handling and module processing. The porous support membrane is, for example, “Millipore Filter VSWP” (trade name) manufactured by Millipore or “Ultra Filter UK10” (trade name) manufactured by Toyo Roshi Kaisha, Ltd.
And other commercially available materials such as "Office of Saline Water Research and Development Progress Report" No. 359 (1968). For the material of the porous support membrane, use a homopolymer or a copolymer such as polysulfone, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide, polyphenylene sulfide sulfone alone or a blend of these polymers. be able to. Among these materials, polysulfone is generally used because of its high chemical, mechanical and thermal stability and easy molding. For example, a solution of polysulfone in dimethylformamide (DMF) is cast to a certain thickness on a densely woven polyester cloth or nonwoven fabric, and is cast in an aqueous solution containing 0.5% by weight of sodium dodecyl sulfate and 2% by weight of DMF. By wet coagulation, a porous support membrane having a surface with fine pores having a diameter of several tens nm or less can be obtained.

The porous support membrane is coated with an ultrathin film to produce a composite semipermeable membrane. The coating of the ultrathin film according to the present invention comprises coating the surface of the porous membrane with an aqueous solution of a water-soluble polyfunctional reagent having two or more reactive groups in one molecule, and then coating the porous membrane with the water-soluble polyfunctional reagent. The method is carried out by coating with a solution of a polyfunctional reagent capable of reacting with

Here, the water-soluble polyfunctional reagent having two or more reactive groups in one molecule is an aliphatic, aromatic or heterocyclic compound having two or more reactive groups, Any one may be used as long as it is soluble in water and reacts with a polyfunctional reagent to form a water-insoluble crosslinked polymer. The reactive group may be an amino group, a hydroxyl group, or the like, even if two or more reactive groups are the same. It may also be different. Generally, for example, m
-Phenylenediamine, p-phenylenediamine, 1,
Aromatic amines such as 3,5-triaminobenzene and para-xylylenediamine; aliphatic amines such as ethylenediamine, propylenediamine, dimethylethylenediamine, piperazine, aminomethylpiperidine, and 1,3-bis-4-piperidylpropane; Polyethylenediamine, polyallylamine, aminopolymers such as polymers obtained by modifying polyepihalohydrin with the above monomer amines, aliphatic alcohols such as ethylene glycol, glycerin and propylene glycol, aromatic alcohols such as dihydroxybenzene and trihydroxybenzene, polyvinyl alcohol A polyol type polymer such as alcohol is used. Among them, from the viewpoint of reactivity and performance of the obtained film, polyfunctional amino compounds, particularly m-phenylenediamine, p-phenylenediamine, aromatic amines such as 1,3,5-triaminobenzene, ethylenediamine, Preferred are aliphatic amines such as piperazine and aminomethylpiperidine, and amino polymers such as a polymer obtained by modifying polyepihalohydrin with the above monomer amines. These water-soluble compounds having two or more reactive groups in one molecule can be used alone or as a mixture. These water-soluble compounds are 0.1 to 20% by weight.
Used as an aqueous solution of The aqueous solution may be mixed with another water-soluble compound as needed.

The application of the aqueous solution of the water-soluble polyfunctional reagent to the surface of the porous support membrane includes a method of coating or a method of immersing the porous support membrane in the aqueous solution. After applying the aqueous solution to the porous support membrane, it is common to provide a draining step in order to remove the excess aqueous solution. As a draining method, for example, the membrane surface is held in a vertical direction and naturally drained. There are a method of spraying, a method of blowing gas to the film surface, and a method of wiping with a sponge.

As the polyfunctional reagent capable of reacting with the above-mentioned water-soluble polyfunctional reagent, polyfunctional acid halides, polyfunctional isocyanate compounds and the like can be used. For example, examples of polyfunctional acid halides include trimesic acid halide, benzophenone tetracarboxylic acid halide, trimetic acid halide, pyromethic acid halide, isophthalic acid halide, terephthalic acid halide, naphthalenedicarboxylic acid halide, diphenyldicarboxylic acid halide, and pyridinedicarboxylic acid halide. Aromatic polyfunctional acid halides such as benzenedisulfonic acid halide and chlorosulfonylisophthalic acid halide, and aromatic diisocyanate compounds such as toluene diisocyanate are used as isocyanate compounds. Among these compounds, aromatic acid chlorides, in particular, isophthalic acid chloride, terephthalic acid chloride, trimesic acid chloride, and mixtures thereof are preferable in terms of ease of reaction and separation performance of the obtained membrane.

The organic solvent in which the polyfunctional reagent is dissolved is immiscible with water, and it is necessary that the polyfunctional reactive reagent be dissolved and the porous support membrane is not destroyed. Any material can be used as long as it can form a polymer. In consideration of a substance that does not destroy the ozone layer, a hydrocarbon solvent is preferable as the organic solvent in consideration of availability and the like. As a solvent that is relatively difficult to evaporate at normal temperature and normal pressure, a hydrocarbon compound having 6 or more carbon atoms is preferable. Further, in consideration of handling safety, a hydrocarbon compound having 8 or more carbon atoms or a flash point of 10 ° C. or more is preferable. More preferably, the carbon number is 8 to 20 or the flash point is 10 to 300.
° C. If the carbon number is 8 or less or the flash point is 10 ° C. or less, there is a risk of explosion or ignition, and handling is difficult. Further, when the carbon number is 20 or more or the flash point is 300 ° C. or more, the viscosity increases,
Handling is difficult due to problems such as a high freezing point and easy solidification. Specifically, linear or branched saturated or unsaturated aliphatic is preferable, and octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, heptadecane, hexadecane and the like, cyclooctane, ethylcyclohexane, 1-octene , 1-decene or the like, or a mixture thereof is preferably used.

The concentration of the polyfunctional reagent is not particularly limited. However, if the concentration is too low, the formation of an ultra-thin film as an active layer may be insufficient, resulting in a disadvantage. If the concentration is too high, it is disadvantageous in terms of cost. , About 0.01 to 1.0% by weight. If necessary, other compounds to be mixed with the solvent may be mixed in the solution of the polyfunctional reagent. Examples of the substance to be mixed include polar compounds such as dimethylformamide, dimethylsulfoxide, n-methylpyrrolidone, and diethylformamide, and a surfactant.

The application of the solution of the polyfunctional reagent to the surface of the porous support membrane coated with the solution of the water-soluble polyfunctional reagent may be performed by a coating method, a method using a coating roll, or a method in which the porous support film is dissolved in the solution. Immersion method.

By applying the solution of the polyfunctional reagent to the surface of the porous support membrane coated with the aqueous solution of the water-soluble polyfunctional reagent, a crosslinking reaction or polycondensation reaction occurs on the surface of the porous support membrane, and the crosslinked ultrathin film A layer forms. In general, the reaction is completed in a short time, but depending on the case, the reaction rate, the thickness of the resulting ultrathin film, and the density can be controlled by changing the reaction time, for example, by increasing the reaction time. The reaction time is a time from contact of the polyfunctional reagent to deactivation of the functional group, and is preferably 1 second to 10 minutes. If the reaction time is too short, the reaction does not proceed sufficiently, resulting in a film having many defects. If the reaction time is too long, the reaction may proceed too much, resulting in low water production. The thickness of the obtained ultrathin film is 5 nm to 10 μm, but is preferably 1 μm or less from the viewpoint of the water permeability of the semipermeable composite film.

After applying the solution to the porous support membrane, it is necessary to remove the excess polyfunctional reagent solution and organic solvent. Usually, in order to sufficiently perform a crosslinking reaction or an interfacial polycondensation reaction, an excess solution of a polyfunctional reagent is applied. Therefore, after the completion of the reaction or during the reaction, the polyfunctional reagent remaining on the film surface may cause a defect or cause a side reaction to change the surface state of the film. In addition, the organic solvents remaining on the film surface cause the surface of the film to become hydrophobic, which causes deterioration of the film performance. Further, there is a possibility that these remaining reagents and organic solvents are eluted when the membrane is used, thereby deteriorating the quality of permeated water and contaminating the concentrated water. Therefore, it is necessary to remove the organic solvent and the polyfunctional reagent from the composite membrane in order to obtain high membrane performance or eliminate elution into permeated water and concentrated water during use.

In the method of the present invention, when the excess organic solvent and the polyfunctional reagent are removed after the completion of the reaction, the organic solvent and the organic solvent are removed from the composite semipermeable membrane using two or more air knives.
It is characterized in that the polyfunctional reagent is removed.

In the air knife described above, it is necessary to set the direction of the slit so that air or an inert gas is blown out from the slit-shaped nozzle and the solution on the film surface moves downward. Regarding the direction of the slit, the angle between the air knife and the film is preferably 5 to 90 degrees, and more preferably 10 to 85 degrees, when the direction of travel of the film is 0 degree. When the direction of the air blowing direction of the air knife and the direction of the flow of the wind on the membrane surface are directed to the traveling direction of the membrane,
The organic solvent is carried to the subsequent step, which is not preferable from the viewpoint of removing the solvent.

The angle of each step can be set freely within the above range. Although not particularly limited, for example, the second stage can be set to an acute angle more than the first stage, and the third stage can be set to an acute angle than the second stage, and can be appropriately selected according to the process. .

At this time, the angle with respect to the horizontal direction of the porous support membrane or the composite semipermeable membrane is preferably horizontal or uphill, and may be in an overhang state of 90 degrees or more. In a state where the film has a downward gradient, the solvent flows down in the direction in which the film travels, making removal difficult, which is not preferable.

It is necessary to select a preferable value of the velocity of the air or the inert gas blown from the nozzle depending on the viscosity of the solvent to be used, and it is preferable that the velocity at the outlet of the nozzle is 5 to 50 m / sec. At a lower speed, the effect of removing the solution from the film surface decreases. At a higher speed, the solution becomes mist-like, and even at a temperature below the flash point of the solvent, it is dangerous.

The temperature of the air or inert gas blown out from the nozzle is preferably 10 to 50 ° C., and more preferably a temperature lower than the flash point of the solvent used.

The air knife is installed continuously along the film surface, and the blowing speed is set to be higher than that of the first stage, that of the second stage, and that of the third stage that is higher than that of the second stage. Thus, the solution on the film surface can be effectively removed by a method in which air knives are provided in multiple stages. Although not particularly limited, for example, the subsequent stage is 0.01 to
Preferably, the speed is about 50 m / sec, and 0.5 to 20 m / sec.
More preferably, it is faster by about a second. The same effect can be obtained by installing air knives on both sides if the membrane is a flat membrane, and the same effect can be obtained by installing air knives with ring-shaped slits in multiple stages for hollow fiber membranes. Is obtained.
The solvent may be removed from the back side of the coating surface by using an air knife. However, since the solvent is not so related to the separation performance, such removal may not be necessary. You may remove with a roll etc.

After completion of the reaction, the excess organic solvent and the polyfunctional reagent are collected downward with an air knife, and are collected by placing a saucer. Some of the evaporated solvent is collected by suction.

A draining step may be provided as a first stage of removal before the air knife. By providing a draining step, the total amount of the solution to be removed is reduced, and the time required for removal with an air knife can be shortened, the wind speed can be reduced, and the like. The removal effect increases. Examples of the liquid draining method include a method in which the film surface is held vertically and caused to flow naturally, a method in which gas is blown to the film surface, and a method in which the film surface is wiped off with a sponge. In addition, extraction is performed with an aqueous solution of a water-soluble organic substance in order to remove a trace amount of an organic solvent remaining after removing the solution with an air knife, a polyfunctional reagent, and a by-product reacted with the polyfunctional reagent, and then, washing of the extract. It is preferable to carry out washing with water in order to carry out. Furthermore, various post-treatments may be performed to control the performance of the composite membrane according to the purpose.

When a normal organic solvent is used for film formation, the solvent usually evaporates at normal temperature and normal pressure in a film formation atmosphere. In the conventional method of forming a composite film using a CFC-based solvent, removal was performed by evaporation. However, removal of the organic solvent by evaporation makes it difficult to recover the solvent, and in the case of a flammable or harmful organic solvent, there is a problem in terms of safety. Also,
When a solvent having low flammability is used, there is also a problem that a high flash point generally raises a boiling point and makes it difficult to evaporate. Heating may be performed to evaporate a solvent having a high flash point, but this is also a problem because the risk of ignition increases. The method of the present invention can be used for all organic solvents used for forming a composite membrane.

Further, the form of the composite membrane of the present invention may be a flat membrane or a hollow fiber. In addition, the obtained composite membrane can be used by incorporating a flat membrane into a spiral, tubular, or plate and frame module, and incorporating hollow fibers into a module after bundling.
The present invention does not depend on the use form of these films.

The apparatus for producing a composite semipermeable membrane according to the present invention includes an apparatus (1) for applying an aqueous solution of a water-soluble polyfunctional reagent to the surface of a porous support membrane, and a polyfunctional organic solvent immiscible with water. A composite semipermeable membrane in which a portion (3) for removing the organic solvent and the polyfunctional reagent from the composite semipermeable membrane is arranged in series using a reagent solution application device (2) and two or more air knives. Production equipment. The device (1) for applying an aqueous solution of a water-soluble polyfunctional reagent includes devices such as dropping of a solution onto a porous support membrane, showering, coating with a mouthpiece or the like, and impregnation of the aqueous support with the porous support membrane. However, the device of the present invention may be any of these. In addition, a coating device (2) for applying a solution of a polyfunctional reagent of an organic solvent immiscible with water is also used as a device for dropping, showering, coating with a base or the like, impregnating the organic solution, or the like. However, the device of the present invention may be any of these. further,
For removing the organic solvent and the polyfunctional reagent from the composite semipermeable membrane, an air knife is continuously installed in two or more stages, or a removing device in which two or more air knives are installed on both surfaces of the membrane. However, the device of the present invention may be any of these.

In the production apparatus of the present invention, an apparatus (1) for applying an aqueous solution of a water-soluble polyfunctional reagent to the surface of a porous support membrane, and a polyfunctional reagent of an organic solvent immiscible with water are used. It is important to arrange the portions (3) for removing the organic solvent and the polyfunctional reagent from the composite semipermeable membrane in series in this order by using a solution coating device (2) and an air knife having two or more stages. However, if necessary, a device for washing the porous support film at the top, a device for applying an aqueous solution of a water-soluble polyfunctional reagent to the surface of the porous support film (1), and a device for draining the aqueous solution,
A device for draining the organic solvent may be provided after the device (2) for applying a solution of a polyfunctional reagent of an organic solvent immiscible with water. Furthermore, using an air knife of two or more stages,
A water-soluble organic substance for removing the organic solvent, the trace amount of the organic solvent remaining after the portion (3) for removing the polyfunctional reagent from the composite semipermeable membrane, the polyfunctional reagent and by-products reacted with the polyfunctional reagent. A water washing device or a device for post-treatment of the composite membrane may be attached in series to perform extraction with an aqueous solution of the composite membrane and then wash the extract.

[0041]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

In the examples, the exclusion (desalting) rate was determined by the following equation.

Rejection rate (%) = {1- (concentration of solute in permeate) / (concentration of solute in feed)} X100 The amount of fresh water is the amount of permeate permeating through the membrane per unit area per unit time. I asked.

REFERENCE EXAMPLE 1 Taffeta made of polyester fiber having a length of 30 cm and a width of 20 cm (vertical yarn, multifilament yarn having a width of 150 denier, weaving density: 90 / inch, width: 67 / Inches, thickness of 160 μm) were fixed on a glass plate, and polysulfone (Udel manufactured by Amoco) was placed on the glass plate.
P-3500) 15% by weight dimethylformamide (D
The MF) solution was cast at a room temperature (20 ° C.) with a thickness of 200 μm, immediately immersed in pure water and left for 5 minutes to obtain a fiber-reinforced polysulfone support membrane (hereinafter FR-PS).
(Abbreviated as support film). The F thus obtained
R-PS pure water permeability coefficient of the support film (thickness 210～215Myuemu) pressure 1 kg / cm ^2, as measured at a temperature 25 ° C. 0.0
It was 0.5 to 0.01 g / cm ² · sec · atm.

Example 1 The FR-PS support membrane obtained in Reference Example 1 was immersed in a 1.5% by weight aqueous solution of a piperazine-modified polyepiodohydrin reactant for 2 minutes. After removing the excess aqueous solution from the surface of the FR-PS support membrane, it was dried at 120 ° C. for 1 minute, and 0.1% by weight of trimesic acid chloride dissolved in n-octane.
The solution was coated so that the surface was completely wet, and allowed to stand for 1 minute. Next, the membrane was vertically set and the excess solution was drained off to remove 25 m of air at 15 m / sec with the first air knife and 25 m of air with the second air knife.
The solution was sprayed onto the membrane surface at m / sec to remove the solution. One more
Heat treatment was performed at 20 ° C. for 5 minutes. The obtained film was immersed in a 10% by weight aqueous solution of isopropanol for 2 minutes to remove the remaining solvent and unreacted substances, and washed with water. The composite membrane thus obtained was subjected to reverse osmosis evaluation using a 500 ppm aqueous solution of sodium sulfate under conditions of pH 6.5, 25 ° C, and 735 KPa. As a result, the exclusion rate was 99.0% and the amount of water produced was 2.
Performance of ² m ³ / m ² · day was obtained.

Example 2 The FR-PS support membrane obtained in Reference Example 1 was replaced with piperazine
It was immersed in a 2% by weight aqueous solution for 2 minutes. After removing the excess aqueous solution from the surface of the FR-PS support membrane, a 0.5% by weight solution of trimesic acid chloride dissolved in n-decane was coated so that the surface was completely wetted, and allowed to stand for 1 minute. . Next, the membrane was set vertically and the excess solution was drained off to remove the solution.
Second, air at 25 ° C. was blown onto the membrane surface at 25 m / sec with a second-stage air knife to remove the solution. The obtained membrane was immersed in a 1% by weight aqueous solution of sodium dodecylbenzenesulfonate for 2 minutes, and then washed with water. The composite membrane thus obtained was subjected to reverse osmosis evaluation using a 1500 ppm aqueous solution of sodium chloride under conditions of pH 6.5, 25 ° C., and 1.47 MPa. A performance of .10 m ³ / m ² · day was obtained.

Example 3 The FR-PS support membrane obtained in Reference Example 1 was immersed in a 5% by weight aqueous solution of a mixture of piperazine / ethylenediamine at a weight ratio of 20/1 for 2 minutes. After the excess aqueous solution was removed from the surface of the FR-PS support membrane, a 0.5% by weight solution of a 1/1 mixture of trimesic acid chloride / terephthalic acid chloride was coated on n-decane so that the surface was completely wetted. For 1 minute. Next, the membrane was set vertically and the excess solution was drained off and removed.
5 ° C air at 15m / sec, 25 ° C with second stage air knife
Of air was blown onto the membrane surface at 25 m / sec to remove the solution. The obtained membrane was immersed in a 1% by weight aqueous solution of sodium dodecylbenzenesulfonate for 2 minutes, and then washed with water.
The composite membrane thus obtained was prepared using a 500 ppm aqueous solution of sodium chloride at pH 6.5, 25 ° C. and 1.47.
The reverse osmosis was evaluated under the condition that 1 ppm of sodium hypochlorite was mixed at 1 MPa.
A performance of 0.63 m ³ / m ² · day of fresh water was obtained.

Example 4 The FR-PS support membrane obtained in Reference Example 1 was prepared using piperazine /
5/1 by weight of 1,3 bis (4-piperidyl) propane
The mixture was immersed in a 3% by weight aqueous solution for 2 minutes. FR-PS
After removing the excess aqueous solution from the surface of the support membrane, a 0.3% by weight n-decane solution of trimesic acid chloride was coated so that the surface was completely wetted, and allowed to stand for 1 minute. Next, the membrane was set vertically and the excess solution was drained off to remove the solution.
Second, air at 25 ° C. was blown onto the membrane surface at 25 m / sec with a second-stage air knife to remove the solution. The obtained membrane was immersed in a 1% by weight aqueous solution of sodium dodecylbenzenesulfonate for 2 minutes, and then washed with water. The composite membrane thus obtained was subjected to reverse osmosis evaluation under the condition of mixing 1 ppm sodium hypochlorite at pH 6.5, 25 ° C. and 368 KPa using a 500 ppm sodium chloride aqueous solution. 83.3%, water production 0.60 m ³ / m
² days performance was obtained.

Example 5 The FR-PS support film obtained in Reference Example 1 was immersed in a 3% by weight aqueous solution of N, N'dimethylethylenediamine for 2 minutes. After removing the excess aqueous solution from the surface of the FR-PS support membrane, a 0.3% by weight n-decane solution of trimesic acid chloride was coated so that the surface was completely wetted, and allowed to stand for 1 minute. Next, the membrane was vertically set, and the excess solution was drained to remove the solution. After that, air at 25 ° C. was supplied at a rate of 15 m / sec with a first-stage air knife at 25 m / sec with a second-stage air knife. The solution was removed by spraying on the membrane surface. The obtained membrane was immersed in a 1% by weight aqueous solution of sodium dodecylbenzenesulfonate for 2 minutes, and then washed with water. The composite membrane thus obtained was prepared using a 1500 ppm aqueous solution of sodium chloride at pH 6.5, 25 ° C. and 1.47 MPa.
As a result of performing reverse osmosis evaluation under the conditions of
% And a water production amount of 1.1 m ³ / m ² · day were obtained.

Example 6 The FR-PS support film obtained in Reference Example 1 was immersed in a 2% by weight aqueous solution of m-phenylenediamine for 1 minute. FR-P
After removing the excess aqueous solution from the surface of the S support membrane, a 0.1% by weight solution of trimesic acid chloride in n-decane was coated so that the surface was completely wetted, and allowed to stand for 1 minute. Next, the membrane was set vertically and the excess solution was drained off to remove the solution.
Second, air at 25 ° C. was blown onto the membrane surface at 25 m / sec with a second-stage air knife to remove the solution. The obtained membrane was immersed in a 1% by weight aqueous solution of sodium dodecylbenzenesulfonate for 2 minutes, and then washed with water. The composite membrane thus obtained was subjected to reverse osmosis evaluation using a 1500 ppm aqueous solution of sodium chloride under conditions of pH 6.5, 25 ° C. and 1.47 MPa. As a result, the exclusion rate was 99.3% and the amount of water produced was 0. A performance of .80 m ³ / m ² · day was obtained.

Example 7 A composite membrane was obtained in the same manner as in Example 6, except that m-phenylenediamine in Example 6 was changed to p-phenylenediamine. Further, when the membrane was evaluated in the same manner as in Example 6, the exclusion rate was 99.0% and the water production was 0.77 m ³ / m ^2.
-Daily performance was obtained.

Example 8 A composite membrane was obtained in the same manner as in Example 6 except that the 2% aqueous solution of m-phenylenediamine was changed to a 3% aqueous solution of triaminobenzene and trimesic acid chloride was changed to terephthalic acid chloride. Was. Further, when the membrane was evaluated in the same manner as in Example 6, the rejection rate was 99.6%, and the performance of producing water 0.66 m ³ / m ² · day was obtained.

Example 9 The FR-PS support membrane obtained in Reference Example 1 was immersed in a mixed aqueous solution of m-phenylenediamine / triaminobenzene (mixing ratio 50/50, total amine concentration 2% by weight) for 1 minute. After removing the excess aqueous solution from the surface of the FR-PS support membrane, the surface was completely treated with a mixed solution of trimesic acid chloride / tephthalic acid chloride (mixing ratio 50/50, solvent n-decane, total concentration 0.1% by weight). It was coated so as to be wet and left to stand for 1 minute. Next, the membrane was vertically set, and the excess solution was drained to remove the solution. After that, air at 25 ° C. was supplied at a rate of 15 m / sec with a first-stage air knife at 25 m / sec with a second-stage air knife. The solution was removed by spraying on the membrane surface. The obtained membrane was immersed in a 1% by weight aqueous solution of sodium dodecylbenzenesulfonate for 2 minutes, and then washed with water. 1500 ppm of the composite membrane thus obtained was used.
PH 6.5, 25 ° C.
As a result of performing reverse osmosis evaluation under the condition of 1.47 MPa,
The rejection was 99.6%, and the performance was 1.2 m ³ / m ² · day.

Example 10 Taffeta made of polyester fiber having a length of 30 cm and a width of 20 cm (vertical yarn, multifilament yarn having a width of 150 denier, weaving density 90 yarns / inch, horizontal width 67 yarns / Inch, thickness 160 μm) was fixed on a glass plate, and a polyether sulfone 18% by weight dimethylformamide (DMF) solution was cast at a thickness of 100 μm at room temperature (20 ° C.) and immediately immersed in pure water. And left for 5 minutes to produce a fiber-reinforced polyethersulfone support membrane.

Using the porous support membrane thus obtained, a composite membrane was obtained in the same manner as in Example 6.

Further, when the membrane was evaluated in the same manner as in Example 6, the exclusion rate was 99.0% and the amount of fresh water was 1.23 m.
A performance of ³ / m ² · day was obtained.

Example 11 Taffeta made of polyester fiber having a length of 30 cm and a width of 20 cm (a multifilament yarn having a warp yarn and a weft thread of 150 denier, a weaving density of 90 yarns / inch and a width of 67 yarns / Inches, thickness 160 μm) was fixed on a glass plate, and polyphenylene sulfide sulfone 2
0% by weight of 3-dimethyl-2-imidazocidinone (DM
I) The solution was cast at a room temperature (20 ° C.) with a thickness of 100 μm, immediately immersed in pure water and left for 5 minutes to prepare a fiber-reinforced polyphenylene sulfide sulfone support membrane.

Using the porous support membrane thus obtained, a composite membrane was obtained in the same manner as in Example 6. further,
The membrane was evaluated in the same manner as in Example 6. As a result, an exclusion rate of 99.0% and a water production of 0.74 m ³ / m ² · day were obtained.

Example 12 The fiber-reinforced polyphenylene sulfide sulfone support membrane obtained in Example 11 was oxidized with a peracetic acid aqueous solution to obtain a fiber-reinforced polyphenylene sulfone support membrane.

Using the porous support membrane thus obtained, a composite membrane was obtained in the same manner as in Example 6.

Further, when the membrane was evaluated in the same manner as in Example 6, the exclusion rate was 98.7% and the water production was 0.75 m.
A performance of ³ / m ² · day was obtained.

COMPARATIVE EXAMPLE 1 The air at 25.degree.
A composite film was obtained in the same manner as in Example 6, except that the film was sprayed on the film surface at 5 m / sec. Further, when the membrane was evaluated in the same manner as in Example 6, the exclusion rate was 99.2% and the amount of fresh water was 0.1%.
A performance of 70 m ³ / m ² · day was obtained.

Example 13 A composite membrane was obtained in the same manner as in Example 6, except that a third-stage air knife was added to Example 6, and air at 25 ° C. was blown onto the membrane surface at 35 m / sec. Further, the membrane was evaluated in the same manner as in Example 6. As a result, an exclusion rate of 99.5% and a water production of 0.85 m ³ / m ² · day were obtained.

Example 14 The air at 25 ° C. was heated to 35 ° C. with the second stage air knife of Example 6.
A composite membrane was obtained in the same manner as in Example 6, except that the composition was changed to.
Further, the membrane was evaluated in the same manner as in Example 6. As a result, an exclusion rate of 99.6% and a water production of 0.95 m ³ / m ² · day were obtained.

Example 15 A composite film was obtained in the same manner as in Example 6 except that the solvent for trimesic acid chloride in Example 6 was changed to ethylcyclohexane. Further, when the membrane was evaluated in the same manner as in Example 6, the rejection was 99.3%, and the performance of producing water was 0.77 m ³ / m ² · day.

Example 16 A composite membrane was obtained in the same manner as in Example 6, except that the solvent for trimesic acid chloride in Example 6 was changed to 1-decene. Further, when the membrane was evaluated in the same manner as in Example 6, the rejection was 99.3% and the amount of fresh water was 0.74 m ^3.
/ M ² · day.

Example 17 A composite membrane was obtained in the same manner as in Example 6, except that the solvent for trimesic acid chloride in Example 6 was changed to n-decane. Further, when the membrane was evaluated in the same manner as in Example 6, the rejection was 99.2%, and the amount of fresh water was 0.72 m ³ /
A performance of m ² · day was obtained.

Example 18 A composite film was obtained in the same manner as in Example 6, except that the solvent for trimesic acid chloride in Example 6 was changed to a mixture of n-paraffins having 9 to 12 carbon atoms. Further, when the film was evaluated in the same manner as in Example 6, the exclusion rate was 9%.
Performance of 9.2% and water production of 0.72 m ³ / m ² · day was obtained.

[0069] In Comparative Example 2 Example 6, without <br/> removal of the solution by the air knife, was directly evaluated in the same manner as in Example 6, rejection 85.3% desalination amount 0. 55m ³ / m ²・
It was day performance.

[0070]

According to the method and apparatus of the present invention, a composite semipermeable membrane having a high separation performance even when a hydrocarbon-based solvent having no ozone destruction coefficient and having a high flash point having high handling safety is used. Can be obtained. Furthermore, the solvent and the solvent used for film formation can be safely and effectively removed and recovered by the method and apparatus of the present invention. In addition, the performance of the obtained composite semipermeable membrane was also improved.

[Brief description of the drawings]

FIG. 1 shows a composite semipermeable membrane device according to the present invention.

[Explanation of symbols]

1: Apparatus for applying an aqueous solution of a water-soluble polyfunctional reagent to the surface of a porous support membrane 2: Apparatus for applying a solution of a polyfunctional reagent of an organic solvent immiscible with water 3: Air knife 4: Porous support membrane or Is a composite semipermeable membrane

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-76740 (JP, A) JP-A-8-972 (JP, A) JP-A-7-84358 (JP, A) (58) Survey Field (Int. Cl. ⁷ , DB name) B01D 67 / 00,71 / 64,71 / 82

Claims (8)

(57) [Claims] An aqueous solution of a water-soluble polyfunctional reagent is applied to the surface of a porous support membrane, and a solution obtained by dissolving a polyfunctional reagent that reacts with the water-soluble polyfunctional reagent in an organic solvent immiscible with water is used. after coating, using a two-stage or more air knives, preceding Eana
Air knife air downstream of IF air blowing speed
A method for producing a composite semipermeable membrane, wherein the organic solvent is removed by increasing the blowing speed . 2. A method for producing a composite semipermeable membrane according to claim 1, wherein the ultra-thin film is an ultra thin film of crosslinked polyamide. 3. The process for producing a composite semipermeable membrane according to claim 1 or 2, wherein the water-soluble polyfunctional reagent is a multi-functional amine. 4. The process for producing a composite semipermeable membrane according to any one of claims 1 to 3, polyfunctional reagent is characterized in that the polyfunctional acid halide. 5. The water in the method of manufacturing the composite semipermeable membrane of any of claims 1-4 serial <br/> mounting, wherein the non-miscible organic solvent is a solvent of hydrocarbon. 6. The method for producing a composite semipermeable membrane according to claim 5 , wherein the hydrocarbon-based solvent is a hydrocarbon having 6 or more carbon atoms. 7. A method for producing a composite semipermeable membrane according to claim 5 or 6, wherein the solvent of the hydrocarbon is a solvent of the above the flash point 10 ° C.. 8. An apparatus for applying an aqueous solution of a water-soluble polyfunctional reagent,
Two or more air knives provided after the device for applying a solution of a polyfunctional reagent in a water-immiscible solvent ;
The upper air knife is the air blowing speed of the previous air knife.
An apparatus for producing a composite semipermeable membrane, characterized in that the air blowing speed of an air knife at a later stage than the temperature is higher .