JPH09187631A - Production of composite reverse-osmosis membrane and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the composite semipermeable membrane exhibiting effective high separation performance by using an inexpensive solvent easy to handle without destroying the ozone layer. SOLUTION: This composite semipermeable membrane having an extremely thin membrane is formed as follows. Namely, an aq. soln. of a water-soluble multifunctional reagent is applied on the surface of a porous supporting membrane, a soln. of a multifunctional reagent reacting with the water-soluble multifunctional reagent in an org. solvent immiscible with water is applied, and then the composite semipermeable membrane is radiation-heated or convectionally heated from the rear of the coated surface to remove the org. solvent.

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 canned water, desalination of seawater, and production of ultrapure water used for production of semiconductors. Furthermore, it is possible to selectively remove or recover pollutants or useful substances contained in dyeing wastewater, electrodeposition paint wastewater, etc., and thus contribute to the closure of 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 canned water or seawater, removing harmful substances, recovering useful substances, treating wastewater, and the like. .

[0003]

2. Description of the Related Art Regarding separation of a mixture, there are various techniques for removing substances (for example, salts) dissolved in a solvent (for example, water), but in recent years, membrane separation has been performed as a process for saving energy and resources. The law is being used. Microfiltration (MF; Micro)
Filtration method, ultrafiltration (UF; Ultr)
afiltration method, reverse osmosis (RO; Rev)
rse 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, reverse osmosis is used to desalinate 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 obtain drinking water from seawater, canned water, and water containing harmful substances, and has also been used for the production of industrial ultrapure water, wastewater treatment, recovery of valuables, etc. It 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").
alignment by means of an
Osmotic Membrane ”, in Adv
ances in Chemistry Series
# 38, American Chem. So
c. , Washington D .; C. (196
3)). At the time, this membrane had the advantages of excellent basic performance and easy manufacturing, 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 liable to be generated on the membrane surface, and the membrane is deteriorated by the microorganisms, and the membrane is liable to be 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, such as a reverse osmosis membrane of a linear aromatic polyamide, has also been proposed (eg, US Pat. No. 3,567,632). Specification). These asymmetric membranes made of synthetic polymers were improved in terms of microbial resistance, etc., but had the same problems in reverse osmosis performance as cellulose acetate, and a dramatic improvement in basic performance was expected. .

In order to make up for these drawbacks, as a semipermeable membrane having a shape different from that of the asymmetric membrane, a microporous support membrane is coated with an ultrathin film (active layer) which substantially controls the membrane separation performance with different materials. A semipermeable composite membrane was devised. In the semipermeable composite membrane, it is possible to select the most suitable material for each of the active layer and the microporous support membrane, and various membrane forming techniques can be selected.

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

[0008] These semipermeable composite membranes have higher desalination performance than cellulose acetate asymmetric membranes.

Further, these membranes are being improved in durability against chlorine and hydrogen peroxide used for sterilization, and their use is being expanded.

However, even in these semipermeable composite membranes, there were serious defects in the manufacturing process. That is, hexane or CF is commonly used as a solvent for a polymer crosslinking agent or a solvent used for interfacial polycondensation.
It is a solvent 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 for handling and storing the solution, which is a significant disadvantage from an economical and safety point of view as an industrial scale manufacturing process. Is. On the other hand, chlorofluorocarbon (CFC) -based solvents such as CFC-113 are considered to have been most frequently used because they are highly safe and easy to produce a membrane with good performance without toxicity, but recently released into the atmosphere. The use of the specified CFCs as a causative agent of global-scale environmental destruction that destroys the ozone layer has been problematic. Therefore, UNEP
At the call of the United Nations Environment Program, the Vienna Convention on the Protection of the Ozone Layer (1985), Montreal Protocol (1)
987), the Declaration of Helsinki (1989) was adopted, and worldwide use and production was regulated, and 1995 in major countries.
In 2000, it launched a policy to abolish specific CFCs.

Under these circumstances, there has been an urgent need to develop a process and an apparatus that do not use specific CFCs even in the production of composite membranes. Conventionally, in the production of composite membranes, for example, in Japanese Patent Publication No. 63-36803 and US Pat. No. 4,277,344, m-phenylenediamine or p-phenylenediamine was added to the surface of a porous support membrane of polysulfone. A method for obtaining a crosslinked aromatic polyamide membrane by reacting with trimesic acid chloride or a mixture of trimesic acid chloride and isophthalic acid chloride is disclosed. However, the solution of the acid chloride is CFC-11.
3 or n-hexane is used. In addition, Japanese Patent Publication No. 56-500062 and US Pat. No. 4,25
No. 9,183 and JP-A-1-130707 disclose a production method in which piperazine is used in the amine composition to carry out a similar reaction, but this also uses C as a reaction solvent.
This is a problem because FC-113 or n-hexane is used.

The solvent used for the production of these composite membranes has no or little ozone depleting ability, and at the same time it is necessary to consider the safety during handling. JP 6
JP-A 2-49909 discloses a method in which polyvinyl alcohol and an amino compound such as piperazine are allowed to react with trimesic acid chloride on the surface of a polysulfone porous support membrane to crosslink and polymerize. Here, as in the above-mentioned technique, a low boiling hydrocarbon solvent represented by n-hexane and cyclohexane is used as a solvent for trimesic acid chloride, but these solvents have no ozone depleting ability, Most of them have a flash point of 0 ° C. or less, which is a very dangerous solvent because they are extremely flammable. This is especially problematic in production on an industrial scale as described above. In addition, since the solvent has a low boiling point, it is difficult to recover the solvent, and the vapor of the solvent that is not recovered is released into the atmosphere as it is.

In the process for producing a composite membrane by a polymer crosslinking reaction or an interfacial polycondensation reaction on a porous support membrane, a crosslinking agent or a polyfunctional acid halide is contacted with a monomer or polymer which reacts therewith and then a solvent is used. Need to be removed. Conventionally, the solvent was removed by evaporation. Particularly, in the conventional composite membrane manufacturing technique, a CFC-based solvent having a low boiling point is used, so the solvent spontaneously evaporates, and it is not necessary to take a special removal method. Considering that the conventional film forming process will not be changed even in the search and investigation of alternative solvents for specific CFCs, the solvent removal method in the manufacturing process of the composite film is premised on evaporation. The current situation is that it has not been done. It was thought that the boiling point of the solvent must be low to some extent, provided that the solvent is removed by natural evaporation. However, in general, a solvent having a low boiling point to a medium boiling point generally has a low flash point accordingly, and there is a problem that it is difficult to satisfy the above requirements for safety.

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

Japanese Unexamined Patent Publication (Kokai) No. 5-329348 discloses a method for producing a composite semipermeable membrane using a saturated hydrocarbon compound having 7 to 20 carbon atoms. The boiling point of these compounds is 70 to 400 ° C. However, only the description that the boiling point range affects evaporation is not disclosed at all regarding the special removal method of these compounds. Moreover, these examples show that the higher the boiling point of the compound used as the solvent, the lower the amount of water produced.

[0016]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a method for producing a composite semipermeable membrane having high separation performance, which is effective in using an inexpensive and easy-to-handle solvent without destroying the ozone layer. To aim.

[0017]

The present invention basically has the following configuration. That is, “After applying an aqueous solution of a water-soluble polyfunctional reagent on the surface of the porous support membrane and then applying a solution of the polyfunctional reagent that reacts with the water-soluble polyfunctional reagent dissolved in an organic solvent immiscible with water, The method for producing a composite semipermeable membrane having an ultrathin film, characterized in that radiant heating or contact heating from the back surface of the coated surface is performed. ”

In the present invention, the porous support membrane is a layer having substantially no separation performance and is used for imparting strength to an ultrathin film layer (active layer) having substantially separation performance. 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. The size of the fine pores is A structure having a surface of 100 nm or less is preferable. The thickness of the porous support membrane is 1 μm.
It is preferably m to several mm, 10 μm or more from the viewpoint of film strength, and several 100 μm or less from the viewpoint of ease of handling and module processing. The above-mentioned 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.
You can also choose from a variety of commercially available materials, such as "Office of Saline Water Research and Development Progress Report," No. 359 (1968). As the material for the porous support membrane, a homopolymer or copolymer such as polysulfone, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide, or polyphenylene sulfide sulfone is used alone or a blend of these polymers is used. be able to. Among these materials, polysulfone is generally used because it has high chemical, mechanical and thermal stability and is easy to mold. For example, a solution of polysulfone in dimethylformamide (DMF) is cast on a densely woven polyester cloth or non-woven cloth to a certain thickness, which is then poured into 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 most of the surface having 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. In the coating of the ultrathin film of the present invention, the surface of the porous membrane is coated with an aqueous solution of a water-soluble polyfunctional reagent having two or more reactive groups in one molecule, and then the porous membrane is coated with the water-soluble polyfunctional reagent. 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, and is substantially It may be any as long as it is water-soluble and reacts with a polyfunctional reagent to form a water-insoluble cross-linked 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 paraxylylenediamine, 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, Polyol type polymers such as polyvinyl alcohol are used. Among these, polyfunctional amino compounds, particularly aromatic amines such as m-phenylenediamine, p-phenylenediamine, and 1,3,5-triaminobenzene, ethylenediamine, in view of reactivity and performance of the obtained film, Preferred are aliphatic amines such as piperazine and aminomethylpiperidine, and amino polymers such as polymers 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 in combination. These water-soluble compounds are 0.1 to 20% by weight.
Used as an aqueous solution. Other water-soluble compounds may be mixed with the aqueous solution as needed.

The aqueous solution of the water-soluble polyfunctional reagent is applied to the surface of the porous support membrane by a coating method or a method of immersing the porous support membrane in the aqueous solution. After the aqueous solution is applied to the porous support membrane, it is general to provide a liquid draining step to remove the excess aqueous solution. There are a method of blowing, a method of blowing gas on the film surface, a method of wiping with a sponge, and the like.

As the polyfunctional reagent capable of reacting with the water-soluble polyfunctional reagent, a polyfunctional acid halide or a polyfunctional isocyanate compound can be used. For example, examples of polyfunctional acid halides include trimesic acid halide, benzophenone tetracarboxylic acid halide, trimetic acid halide, pyrometic acid halide, isophthalic acid halide, terephthalic acid halide, naphthalenedicarboxylic acid halide, diphenyldicarboxylic acid halide, 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 the isocyanate compound. Among these compounds, aromatic acid chlorides, particularly isophthalic acid chloride, terephthalic acid chloride, trimesic acid chloride, and mixtures thereof are preferable from the viewpoints of easiness of reaction and separation performance of the obtained membrane.

It is necessary that the organic solvent that dissolves the polyfunctional reagent is immiscible with water and that the polyfunctional reactive reagent is dissolved so as not to destroy the porous support membrane. Crosslinking occurs by interfacial polycondensation or interfacial reaction. Any polymer may be used as long as it can form a polymer. Considering the substance that does not destroy the ozone layer, the organic solvent is preferably a hydrocarbon solvent considering the availability. In addition, a hydrocarbon compound having 6 or more carbon atoms is preferable as a solvent that is relatively easy to handle at room temperature and atmospheric pressure and is relatively hard to evaporate. 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 is a hydrocarbon compound. 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,
It is difficult to handle due to problems such as 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, etc., cyclooctane, ethylcyclohexane, 1-octene. , 1-decene, etc., or a mixture thereof is preferably used.

The concentration of the polyfunctional reagent is not particularly limited, but if it is too low, the formation of the ultrathin film which is the active layer may be insufficient, which may be a drawback, and if it is too high, it will be disadvantageous in terms of cost. , 0.01 to 1.0 wt% is preferable. If necessary, the polyfunctional reagent solution may be mixed with other compounds that are mixed with the solvent. Examples of the substance to be mixed include polar compounds such as dimethylformamide, dimethylsulfoxide, n-methylpyrrolidone and diethylformamide, and surfactants.

The coating of the solution of the polyfunctional reagent on the surface of the porous support membrane coated with the solution of the water-soluble polyfunctional reagent is performed by a coating method, a method using a coating roll, or the porous support membrane in the solution. There is a method of immersing in.

By coating the surface of the porous support membrane coated with the aqueous solution of the water-soluble polyfunctional reagent with the solution of the polyfunctional reagent, a crosslinking reaction or a polycondensation reaction occurs on the surface of the porous support membrane, and a crosslinked ultrathin film is formed. Layers form. Generally, the reaction is completed in a short time, but in some cases, the reaction rate, the thickness of the obtained ultra-thin film, and the denseness can be controlled by changing the reaction time such as lengthening the reaction time. The reaction time is the time from the contact of the polyfunctional reagent to the deactivation of the functional group, and preferably 1 second to 10 minutes. If the reaction time is too short, the reaction does not proceed sufficiently and the film has many defects. On the other hand, if the reaction time is too long, the reaction may proceed too much and the amount of water produced may be reduced. The ultrathin film obtained has a thickness of 5 nm to 10 μm, but is preferably 1 μm or less in view of the water permeability of the semipermeable composite membrane, and a thickness greater than this is not preferable because the water permeability may decrease.

After applying the solution to the porous support membrane, it is necessary to remove the excess solution of the polyfunctional reagent and the organic solvent. Usually, in order to sufficiently carry out the crosslinking reaction and the interfacial polycondensation reaction, an excess solution of the polyfunctional reagent is applied. Therefore, after the reaction is completed 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 solvent remaining on the film surface causes the film surface to be hydrophobic and causes deterioration of the film performance. Furthermore, these residual reagents and organic solvents may elute during use of the membrane, deteriorating the quality of the 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 to eliminate elution into permeated water and concentrated water during use.

The method of the present invention is characterized in that the organic solvent and the polyfunctional reagent are removed by heating without contact or contact. The apparatus used for heating itself does not cause ignition or combustion at the film forming site, the operating temperature can be adjusted, and any apparatus that does not deteriorate or deteriorate the composite film may be used. In forming a composite film, a hydrocarbon organic solvent having 6 or more carbon atoms and a solvent having a flash point of 10 ° C. or more are used. Therefore, a non-contact heating method is radiant heating. preferable.

The device used for radiant heating may be any device capable of irradiating the composite film with infrared rays, such as an infrared hot plate and an infrared dryer. Also,
In addition to infrared rays, a device using a halogen lamp or the like can be similarly used. Further, as the installation mode of the radiant heating means, considering the risk of defects due to thermal contraction of the ultra-thin film formed on the coating surface, it is preferable to provide it on the back surface rather than the coating surface of the film, and also considering the efficiency. Then, it is more preferable to provide it on both sides. In addition, when it is provided on both sides, it is preferable to adjust the temperature of the back surface to a temperature higher than that of the coating surface.
It is preferably about -60 ° C.

Means for heating the composite membrane by contact include:
It is preferable to use a heating roll or a heating plate such as a hot plate or both. At this time, if a roll or the like comes into contact with the surface of the composite film, the composite film is deteriorated or deteriorated due to pressure or compression by the device, scratches due to abrasion occur, and when the roll or the like is a high temperature body, It is not preferable because the composite film is deteriorated and deteriorated by the above, and it is preferable to heat from the back surface of the coated surface.

Depending on the type of solvent, it is possible to use both a non-contact heating device and a contact heating device. Although not particularly limited, for example, radiant heating may be used for the coated surface and contact heating may be used for the back surface. Furthermore, hot air having a wind velocity of 2 to 20 m / sec, a temperature of 10 to 80 ° C., and an absolute humidity of 1 g or more of water content per 1 kg of dry gas may be used together.

The operating temperature range of these heating devices is 0.degree.
180 ° C is preferably 5 ° C to 150 ° C, more preferably 5 ° C to 70 ° C. If the temperature is too low, the solvent removal effect is not sufficient, and if the temperature is too high, it is dangerous because the solvent may ignite or explode, and it is difficult to recover the solvent because it deteriorates the solvent, which is not preferable. .

The heating time varies depending on the type of organic solvent used, but is generally preferably 5 seconds or more. If the time is too short, the removal will be insufficient, and it is preferable that the time for the drying effect is long, but the maximum time is appropriately determined depending on the steps to be adopted. For example, when it is adopted during the continuous film forming process of the composite film, it is preferably 5 minutes or less.

Before the heating operation, a draining step may be provided as the first step of removal. By providing the liquid draining step, the total amount of the organic solvent and polyfunctional reagent to be removed by heating is reduced, and it is possible to shorten the heating time, lower the heating temperature, and the like. The effect of removing the functional reagent is increased. Examples of the method of draining liquid include a method of holding the film surface in a vertical direction to allow the film surface to naturally flow down, a method of blowing gas on the film surface, and a method of wiping with a sponge. Further, after the heating operation, it is preferable to wash with water for washing. Further, various post-treatments may be performed to control the performance of the composite membrane depending on the purpose.

When a normal organic solvent is used for film formation, the solvent usually evaporates in a film forming atmosphere at normal temperature and pressure. In the conventional film formation of a composite film using a fluorocarbon solvent, the removal was performed by evaporation.

Further, in order to prevent ignition and explosion of the evaporated organic solvent, it is preferable to remove the evaporated organic solvent to the outside of the system by heating, and as a device therefor, a fan, a suction pump, a vacuum pump or the like is used. preferable.

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 the flat membrane into a spiral, tubular, or plate-and-frame module, or by bundling the hollow fibers and incorporating them into the module.
The present invention does not depend on the usage of these membranes.

The apparatus for producing the composite semipermeable membrane (4) of the present invention refers to the porous support membrane (4) (for convenience, the "composite semipermeable membrane" and the "porous support membrane" have the same reference numerals). (1) for applying an aqueous solution of a water-soluble polyfunctional reagent to the surface of a liquid, and an apparatus for applying a solution of a polyfunctional reagent of an organic solvent immiscible with water (2)
And a heating part (3) placed in series to produce a composite semipermeable membrane. The device (1) for applying the aqueous solution of the water-soluble polyfunctional reagent is a device for dropping the solution onto the porous support membrane, showering, coating with a spinneret or the like, impregnating the aqueous solution with the porous support membrane, and the like. However, the device of the present invention may be any of these. Further, a device (2) for applying a solution of a polyfunctional reagent of an organic solvent immiscible with water is also a device for dropping the organic solution, showering, coating with a spinneret or something similar thereto, and impregnating the organic solution. However, the device of the present invention may be any of these. further,
Examples of the heat-removed portion of the organic solvent include a radiation heating device such as an infrared or visible light irradiation device, a heating roll, and a heating plate such as a hot plate. 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 on the surface of the porous support membrane (4) and an organic solvent immiscible with water. It is important to arrange the coating device (2) for the solution of the polyfunctional reagent and the heating part (3) in this order in series, but if necessary, the cleaning device for the porous support membrane and the porous support membrane An apparatus (1) for applying an aqueous solution of a water-soluble polyfunctional reagent on the surface and a device for draining the aqueous solution, and an apparatus (2) for applying a solution of a polyfunctional reagent of an organic solvent immiscible with water, and then the organic material. A device for draining the solvent may be provided. Further, a device for post-treatment of the composite membrane (4) may be attached in series.

[0040]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

In the examples, the rejection (desalting) rate was calculated by the following equation.

Exclusion rate (%) = {1- (solute concentration in permeate) / (solute concentration in feed)} × 100 Further, the amount of water produced is the amount of permeate that permeates the membrane per unit area per unit time. I asked for.

The manufacturing process having the radiant heating means used in Examples 1 and 3 to 21 is roughly the same as the manufacturing process having the contact type heating means used in FIG. 1 and Example 2. Is.

Reference Example 1 Taffeta (vertical yarn, multifilament yarn of 150 denier weft yarn denier, made of polyester fiber having a length of 30 cm and a width of 20 cm), weaving density of 90 yarns / inch, width 6
7 pieces / inch, thickness 160 μm) is fixed on a glass plate, and polysulfone (Udel P manufactured by Amoco Co., Ltd.) is fixed on the glass plate.
3500) 15 wt% dimethylformamide (DM
F) The solution is cast at a thickness of 200 μm at room temperature (20 ° C.), immediately immersed in pure water and left for 5 minutes to prepare a fiber-reinforced polysulfone support membrane (hereinafter abbreviated as FR-PS support membrane). FR obtained in this way
The pure water permeability coefficient of the PS support membrane (thickness 210 to 215 μm) is 0.00 when measured at a pressure of 1 kg / cm ² and a temperature of 25 ° C.
It was 5 to 0.01 g / cm ² · sec · atm.

Example 1 The FR-PS support film obtained in Reference Example 1 was immersed in a 1.5% by weight aqueous solution of a piperazine-modified polyepiiodohydrin 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 to give 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, after making the membrane vertical and removing the excess solution by draining, it was further heat-treated at 70 ° C. for 10 seconds using an infrared hot plate and washed with water. The composite membrane thus obtained was subjected to reverse osmosis evaluation using a 500 ppm aqueous magnesium sulfate solution under conditions of pH 6.5, 25 ° C. and 735 KPa. As a result, the rejection rate was 99.6% and the amount of water produced was 2.1 m. Performance of ³ / m ² · day was obtained.

Example 2 The FR-PS support membrane obtained in Reference Example 1 was treated with 5 parts of piperazine.
It was immersed in a 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 wet and allowed to stand for 1 minute. . Next, the membrane was made vertical and excess solution was drained and removed, and the obtained membrane was heat-treated at 40 ° C. for 1 minute using a stainless hot plate and washed with water. The composite membrane thus obtained was subjected to reverse osmosis evaluation using a 1500 ppm aqueous sodium chloride solution under conditions of pH 6.5, 25 ° C. and 1.47 MPa, and as a result, the rejection rate was 76.9%,
A water production capacity of 1.00 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 piperazine / ethylenediamine weight ratio of 20/1 for 2 minutes. After removing the excess aqueous solution from the surface of the FR-PS support membrane, n-decane was coated with a 0.5% by weight solution of a 1/1 mixture of trimesic acid chloride / terephthalic acid chloride so as to completely wet the surface. And left for 1 minute. Next, the membrane was made vertical and the excess solution was drained off to remove it, and then the obtained membrane was heat-treated at 40 ° C. for 40 seconds using a halogen lamp type hot plate, and then washed with water. The composite membrane thus obtained was subjected to reverse osmosis evaluation under the condition that 1 ppm of sodium hypochlorite was mixed at a pH of 6.5, 25 ° C. and 1.47 MPa using a 500 ppm aqueous sodium chloride solution, Exclusion rate 94.8%, water production 0.65 m ³ /
The performance of m ² / day was obtained.

Example 4 The FR-PS support membrane obtained in Reference Example 1 was treated with piperazine /
Weight ratio of 1,3 bis (4-piperidyl) propane 5/1
It was immersed in a 3% by weight aqueous solution of the mixture for 2 minutes. FR-PS
After removing the excess aqueous solution from the surface of the support membrane, a 0.3% by weight solution of trimesic acid chloride in n-decane was coated so that the surface was completely wet and allowed to stand for 1 minute. Next, the membrane was made vertical and the excess solution was drained and removed, and the obtained membrane was removed by using an infrared hot plate.
It heat-processed at 5 degreeC for 7 second, and washed with water after that. The composite membrane thus obtained was treated with a 500 ppm aqueous sodium chloride solution at pH 6.5, 25 ° C. and 368 KPa for 1 p.
As a result of performing reverse osmosis evaluation under the condition that pm of sodium hypochlorite was mixed, the exclusion rate was 84.1%, and the amount of water produced was 0.6.
A performance of 1 m ³ / m ² · day was obtained.

Example 5 The FR-PS support membrane 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 film, a 0.3% by weight solution of trimesic acid chloride in n-decane was coated so that the surface was completely wet and allowed to stand for 1 minute. Next, the membrane was made vertical and excess solution was drained and removed, and the obtained membrane was heat-treated at 35 ° C. for 15 seconds using a ceramic hot plate and washed with water.

The composite film thus obtained was treated with 1500
pH 6.5, 2 using ppm sodium chloride aqueous solution
As a result of performing reverse osmosis evaluation under the conditions of 5 ° C. and 1.47 MPa, the rejection rate was 68.9%, and the amount of water produced was 1.13 m ³ / m ^2.
The performance of the day was obtained.

Example 6 The FR-PS support membrane 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 film, a 0.1% by weight solution of trimesic acid chloride in n-decane was coated so that the surface was completely wet and allowed to stand for 1 minute. Next, the membrane was made vertical and the excess solution was drained off and removed, and the obtained membrane was dried at 30 ° C. for 2 hours using an infrared dryer.
It heat-processed for 0 second, and washed with water after that. The composite membrane thus obtained was subjected to reverse osmosis evaluation using 1500 ppm aqueous sodium chloride solution under the conditions of pH 6.5, 25 ° C. and 1.47 MPa. As a result, the rejection rate was 99.4% and the amount of water produced was 0. Performance of 0.81 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. Furthermore, when the membrane evaluation was carried out in the same manner as in Example 6, the rejection rate was 99.4% and the amount of water produced was 0.71 m ³ / m ^2.
・ The performance of the day was obtained.

Example 8 A composite film was obtained in the same manner as in Example 6 except that the 2% aqueous solution of m-phenylenediamine of Example 6 was replaced with a 3% aqueous solution of triaminobenzene, and trimesic acid chloride was replaced with terephthalic acid chloride. It was Furthermore, when the membrane evaluation was performed by the same method as in Example 6, the rejection rate was 99.5%, and the water production rate was 0.70 m ³ / m ² · day.

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 film, the surface was completely washed with a trimesic acid chloride / tephthalic acid chloride mixed solution (mixing ratio 50/50, solvent n-decane, total concentration 0.1% by weight). It was coated so as to be wet and left still for 1 minute. Next, the membrane was made vertical and the excess solution was drained and removed, and the obtained membrane was heat-treated at 50 ° C. for 6 seconds using an infrared hot plate,
Then, it was washed with water. The composite membrane thus obtained is
PH of 6. with a sodium chloride aqueous solution of 00 ppm.
The results of reverse osmosis evaluation under the conditions of 5, 25 ° C. and 1.47 MPa revealed that the rejection rate was 99.4% and the amount of water produced was 1.08 m ³ /
The performance of m ² / day was obtained.

Example 10 Taffeta made of polyester fibers having a length of 30 cm and a width of 20 cm (vertical yarn, weft multi-filament yarn of 150 denier, weft density 90 warps / inch, weft 6)
(7 pieces / inch, thickness 160 μm) are fixed on a glass plate, and a 18 wt% dimethylformamide (DMF) solution of polyether sulfone is cast thereon at a thickness of 100 μm at room temperature (20 ° C.), and immediately purified water is used. A fiber-reinforced polyethersulfone support membrane was prepared by immersing it inside and leaving it for 5 minutes.

A composite membrane was obtained in the same manner as in Example 6 by using the porous support membrane thus obtained.

Further, the film was evaluated in the same manner as in Example 6. The rejection rate was 99.0% and the amount of water produced was 0.82 m.
Performance of ³ / m ² · day was obtained.

Example 11 Taffeta (vertical yarn, multifilament yarn of 150 denier weft-tooth denier) consisting of polyester fibers having a length of 30 cm and a width of 20 cm, weaving density of 90 warps / inch, width 6
7 pieces / inch, thickness 160 μm) is fixed on a glass plate, and polyphenylene sulfide sulfone 20
Weight% 3-dimethyl-2-imidazocidinone (DMI)
The solution was cast at a thickness of 100 μm at room temperature (20 ° C.), immediately immersed in pure water and left for 5 minutes to prepare a fiber-reinforced polyphenylene sulfide sulfone support membrane.

A composite membrane was obtained in the same manner as in Example 6 by using the porous support membrane thus obtained. further,
When the membrane evaluation was carried out in the same manner as in Example 6, the rejection rate was 99.1%, and the water production rate was 0.82 m ³ / m ² · day.

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

A composite membrane was obtained in the same manner as in Example 6 by using the porous support membrane thus obtained. further,
When the membrane was evaluated in the same manner as in Example 6, the rejection rate was 98.6% and the performance of producing water of 0.75 m ³ / m ² · day was obtained.

Example 13 A composite film was obtained in the same manner as in Example 6 except that the heating temperature in Example 6 was changed to 40 ° C. Further, when the membrane evaluation was performed by the same method as in Example 6, the rejection rate was 99.6%, and the water production rate was 0.72 m ³ / m ² · day.

Example 14 Example 1 except that the heating time in Example 13 was changed to 10 seconds.
A composite membrane was obtained in the same manner as in 3. Further, when the film evaluation was performed by the same method as in Example 3, the rejection rate was 99.3%,
A performance of 0.79 m ³ / m ² · day of water production was obtained.

Example 15 A composite film was obtained in the same manner as in Example 6 except that the heating device in Example 6 was changed to a hot plate. Further, when the film evaluation was performed in the same manner as in Example 6, the rejection rate was 99.2.
%, The amount of water produced was 0.81 m ³ / m ² · day.

Example 16 A composite film was obtained in the same manner as in Example 6 except that the heating temperature in Example 6 was changed to 80 ° C. and the heating time was changed to 5 seconds. Further, when the membrane evaluation was carried out in the same manner as in Example 6, the rejection rate was 99.6%, and the water production amount was 0.65 m ³ / m ² · day.

Example 17 A composite membrane was obtained in the same manner as in Example 6 except that ethylcyclohexane was used as the solvent for trimesic acid chloride in Example 6 instead of n-decane. Further, when the membrane was evaluated in the same manner as in Example 6, the rejection rate was 99.3% and the amount of water produced was 0.76 m ³ / m ² · day.

Example 18 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. Furthermore, when the membrane evaluation was carried out in the same manner as in Example 6, the rejection rate was 99.2% and the amount of water produced was 0.73 m ^3.
/ M ² · day performance was obtained.

Example 19 A composite film was obtained in the same manner as in Example 6 except that n-decane as a solvent for trimesic acid chloride in Example 6 was changed to n-dodecane. Further, when the membrane was evaluated in the same manner as in Example 6, the rejection rate was 99.1% and the amount of water produced was 0.80 m.
Performance of ³ / m ² · day was obtained.

Example 20 A composite film was obtained in the same manner as in Example 6 except that n-decane as a solvent for trimesic acid chloride in Example 6 was changed to a mixture of n-paraffins having 9 to 12 carbon atoms. Furthermore, when the film evaluation was performed in the same manner as in Example 6, the rejection rate was 9
The performance was 9.2% and the amount of water produced was 0.74 m ³ / m ² · day.

Example 21 The heat treatment of the film of Example 6 was repeated using a halogen lamp.
A composite film was obtained in the same manner as in Example 6 except that the condition of heating at 0 ° C. for 30 seconds was changed. Furthermore, when the film evaluation was performed by the same method as in Example 6, the rejection rate was 99.1.
%, The amount of water produced was 0.78 m ³ / m ² · day.

Comparative Example 1 In Example 6, when the same process as in Example 6 was carried out without performing the steps after the heat treatment, the rejection rate was 76.7% and the amount of water produced was 0.40 m ³ / m ² ·. It was the performance of the day.

Comparative Example 2 In Example 6, no heat treatment was carried out, only washing was carried out as it was, and evaluation was carried out in the same manner as in Example 6. The exclusion rate was 80.3%, the amount of water produced was 0.43 m ³ / The performance was m ² · day.

Comparative Example 3 In Example 6, the heating time was 5 seconds, other conditions were the same as in Example 6 to form a film, and the film was evaluated in the same manner as in Example 6, with an exclusion rate of 77.7. %, Water production 0.4
The performance was 1 m ³ / m ² · day.

Comparative Example 4 In Example 6, the heating temperature was 90 ° C. and the heating time was 60.
When the film was formed under the other conditions in the same manner as in Example 6 and then evaluated in the same manner as in Example 6,
The rejection rate was 88.9% and the amount of water produced was 0.29 m ³ / m ² · day.

[0075]

EFFECT OF THE INVENTION By the method and apparatus of the present invention, a composite semipermeable membrane having a high separation performance even if a hydrocarbon solvent having no ozone depletion potential and a high flash point solvent having high handling safety is used. Can be obtained. Furthermore, the solvent used for film formation can be effectively removed by the method and apparatus of the present invention.

[Brief description of the drawings]

FIG. 1 shows an apparatus for a composite semipermeable membrane using radiant heating according to the present invention.

FIG. 2 shows an apparatus for a composite semipermeable membrane using backside contact heating in the present invention.

[Explanation of symbols]

1: Device for coating an aqueous solution of a water-soluble polyfunctional reagent on the surface of a porous support membrane 2: Device for coating a solution of a polyfunctional reagent of an organic solvent immiscible with water 3: Heat treatment means 4: Porous support membrane Or composite semi-permeable membrane

Claims (12)

[Claims] 1. An aqueous solution of a water-soluble polyfunctional reagent is applied to the surface of a porous support membrane, and a solution of the polyfunctional reagent that reacts with the water-soluble polyfunctional reagent dissolved in an organic solvent immiscible with water is applied. After that, the method for producing a composite semipermeable membrane having an ultrathin film is characterized in that radiant heating or contact heating is performed from the back surface of the coating surface. 2. The method for producing a composite semipermeable membrane according to claim 1, wherein the radiant heating uses irradiation of infrared rays or visible light. 3. The method for producing a composite semipermeable membrane according to claim 1, wherein the contact heating from the back side of the coated surface is performed by using a heating roll, a heating plate, or both. 4. The method for producing a composite semipermeable membrane according to claim 1, wherein the ultrathin film is a crosslinked polyamide-based ultrathin film. 5. The method for producing a composite semipermeable membrane according to claim 1, wherein the water-soluble polyfunctional reagent is a polyfunctional amine. 6. The method for producing a composite semipermeable membrane according to claim 1, wherein the polyfunctional reagent is a polyfunctional acid halide. 7. The method for producing a composite semipermeable membrane according to claim 1, wherein the water-immiscible organic solvent is a hydrocarbon solvent. 8. The method for producing a composite semipermeable membrane according to claim 7, wherein the hydrocarbon solvent is a hydrocarbon having 6 or more carbon atoms. 9. The method for producing a composite semipermeable membrane according to claim 8, wherein the hydrocarbon solvent is a solvent having a flash point of 10 ° C. or higher. 10. A composite semipermeable membrane is radiantly heated or contacted from the back side of the coating surface after the coating device for the aqueous solution of the water-soluble polyfunctional reagent and the coating device for the solution of the polyfunctional reagent of the water-immiscible organic solvent. A device for manufacturing a composite semipermeable membrane, characterized in that it is provided with means for selectively heating. 11. The apparatus for producing a composite semipermeable membrane according to claim 10, wherein an infrared or visible light irradiation device is provided as means for radiatively heating the composite semipermeable membrane. 12. The apparatus for producing a composite semipermeable membrane according to claim 10, wherein a heating roll, a heating plate, or both are provided as means for contactingly heating the composite semipermeable membrane from the back surface of the coated surface. .