JP2002224546A - Composite semipermeable membrane for sewage disposal and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite semipermeable membrane for sewage disposal wherein a permeation flow rate is stable with the lapse of time and high, and provide an apparatus and a method for sewage disposal using the same. SOLUTION: Sewage is disposed by using the composite semipermeable membrane wherein a covalent bond is formed between a reactive group and an acid halide group remaining on a surface of a separation functional layer by coating an aqueous solution of a compound having at least one reactive group to be reacted with the acid halide group on a surface of a polyamide separation function layer just after providing the polyamide separation function layer on a fine porous support membrane by polycondensating a multifunctional amine compound with a multifunctional acid halide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite semipermeable membrane used for advanced treatment of sewage such as night soil and domestic wastewater.

[0002]

2. Description of the Related Art In recent years, despite increasing demand for water, it has become more difficult to secure a new water source. Therefore, from the viewpoint of increasing environmental awareness and environmental conservation, sewage such as night soil and domestic wastewater should not be discharged from the sewage treatment water for effective use of water resources. Reuse as water is being considered. Conventionally, advanced treatment of sewage using a filtration membrane has been carried out for reuse, but when the target water quality is extremely high, a reverse osmosis membrane with a high rejection rate such as a polyamide-based reverse osmosis membrane is used. Is used.

[0003] When performing treatment using such a reverse osmosis membrane, sewage is physically purified by a screen, sedimentation, a preliminary aeration tank, a first settling tank, and the like, and then biologically treated by an activated sludge method. It is pretreated and supplied to a reverse osmosis membrane to take out permeated water that does not contain organic compounds, nitrogen compounds, salts and the like.

However, when sewage is used as raw water, the raw water contains a surfactant used as a detergent, and the surfactant cannot be sufficiently treated by biological treatment. There is a problem that the separation performance of the reverse osmosis membrane is lowered by being adsorbed on the surface of the reverse osmosis membrane. For this reason, when the above-mentioned treatment with the reverse osmosis membrane is performed, there is a problem that the permeation flow rate is remarkably reduced with the passage of time and stable treatment is difficult.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite semipermeable membrane for sewage treatment having a stable permeation flow rate over time and a large permeation flow rate, and an apparatus and method for sewage treatment using the same. Is what you do.

[0006]

In order to solve the above-mentioned problems, the present invention comprises forming a crosslinked polyamide separation functional layer on a microporous support membrane, wherein a water-soluble compound is covalently bonded to the surface of the separation functional layer. Characterized by a composite semipermeable membrane for sewage that forms

Here, the covalent bond is an amide bond or an ester bond, and at 25 ° C., pH 6.5
The aqueous solution having a NaCl concentration of 1,500 mg / l was applied at a pressure of 1.0 MPa and filtered for 1 hour, and the amount of permeated water was defined as F1, followed by 100 mg / l of polyoxyethylene (10) octyl phenyl ether. Assuming that the amount of permeated water after filtration for 1 hour in addition to the aqueous solution so as to obtain a concentration is F2, the value of 1- (F2 / F1) is 0.3.
5 or less, and at 25 ° C., pH
It is preferable that the amount of permeated water is 0.5 to ³ m ³ / m ² d when an aqueous solution having a NaCl concentration of 1,500 mg / l and a pressure of 1.0 MPa is applied thereto and filtered for 1 hour.

Further, the present invention provides a reactive group which reacts with an acid halide group after a polyfunctional amine compound and a polyfunctional acid halide are polycondensed to provide a polyamide separation function layer on a microporous support membrane. An aqueous solution of a compound having at least one of the above, is coated on the surface of the polyamide separation function layer, and forms a covalent bond between the acid halogen group remaining on the separation function layer surface and the reactive group. It is characterized by a method for producing a film.

Further, it is preferable to treat sewage using any of the above-mentioned composite semipermeable membranes or the composite semipermeable membrane produced by the above-mentioned method, and the sewage after treatment with a microfiltration membrane or an ultrafiltration membrane is preferred. Is more preferably supplied to the composite semipermeable membrane.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The composite semipermeable membrane of the present invention is for purifying and reusing sewage such as night soil and domestic wastewater.
A separation functional layer comprising a polyfunctional amine compound and a polyfunctional acid halide is formed on a microporous support membrane, and a water-soluble compound having at least one reactive group that reacts with an acid halide group is formed on the separation functional layer. It is characterized by forming a covalent bond with an acid halogen group on the surface.

In the present invention, the microporous support membrane is a layer having substantially no separation performance, and is used for imparting strength to a separation functional layer having substantially separation performance.

The microporous support membrane has a structure in which fine pores have a uniform pore diameter from the front surface to the back surface of the membrane, or has fine and fine pores on one side, and the other side has one side. It is preferably an asymmetric structure having holes whose diameter gradually increases until the diameter of the fine holes is 100 nm or less. Further, the thickness of the microporous support membrane is 1 μm to several mm, and is 10 μm or more from the viewpoint of membrane strength, and is several tens in terms of ease of handling and ease of module processing.
It is preferably not more than 00 μm. Further, the material of the microporous support membrane may be a homopolymer or copolymer such as polysulfone, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide, polyphenylene sulfide sulfone, or a blend of these polymers. Can be used. Among these materials, polysulfone is preferable because of its high chemical, mechanical and thermal stability and easy molding.

[0013] The polyfunctional amine compound used in the present invention comprises 2
Any aliphatic or aromatic compound having at least two amino groups may be used. Generally, for example, aromatic amines such as m-phenylenediamine, p-phenylenediamine, 1,3,5-triaminobenzene, paraxylylenediamine, diaminopyridine, ethylenediamine, propylenediamine, dimethylethylenediamine, piperazine, amino Aliphatic amines such as methylpiperidine are used. Among them, aromatic amines, especially m-phenylenediamine, in terms of reactivity and performance of the obtained film,
P-phenylenediamine and 1,3,5-triaminobenzene are preferred. These polyfunctional amine compounds can be used alone or as a mixture.

The polyfunctional acid halides include, for example, trimesic acid halide, benzophenone tetracarboxylic acid halide, trimellitic acid halide, pyromellitic acid halide, isophthalic acid halide, terephthalic acid halide, naphthalenedicarboxylic acid halide, diphenyldicarboxylic acid Aromatic acid halides such as acid halide, pyridinedicarboxylic acid halide, benzenedisulfonic acid halide, and chlorosulfonylisophthalic acid halide can be used. In addition, aliphatic acid halides such as cyclohexanetricarboxylic acid halide and cyclohexanedicarboxylic acid halide can also be used. Above all, it is preferable to use isophthalic acid chloride, terephthalic acid chloride, trimesic acid chloride and a mixture thereof in consideration of solubility in a film forming solvent and characteristics of the obtained composite semipermeable membrane.

The water-soluble compound having at least one reactive group which reacts with an acid halide group is an aliphatic, aromatic or heterocyclic compound, which is substantially soluble in water and has Any compound may be used as long as it reacts with a halide group to form a covalent bond. Examples of the functional group include a hydroxyl group, an amino group, and an epoxy group. For example, aniline,
Aromatic amines such as N, N-dimethylphenylenediamine, aminophenol, m-phenylenediamine, p-phenylenediamine, 1,3,5-triaminobenzene, paraxylylenediamine, methylamine, ethylamine, 2-aminoethanol , Morpholine, glucosamine, ethylenediamine, propylenediamine, dimethylethylenediamine, piperazine, aliphatic amines such as aminomethylpiperidine, methanol, ethanol,
Aliphatic alcohols such as 2,3 epoxy-1-propanol, ethylene glycol, glycerin and propylene glycol; aromatic alcohols such as dihydroxybenzene and trihydroxybenzene; polyallylamine, polyethyleneimine, amine-modified polyepihalohydrin, [1- (1-piperazinylcarbonyl) ethylene], polyvinyl alcohol, partially saponified polyvinyl acetate, polyoxyethylene dipropylamine, a copolymer using a monomer containing an amino group or a hydroxyl group,
A polymer compound such as a partially saponified product of vinyl acetate and methacrylic acid ester copolymer, for example, a partially saponified product of vinyl acetate and 2-methacryloyloxyethyl phosphorylcholine copolymer is also preferably used. Of these, primary or secondary amino compounds or alcohols are preferred from the viewpoints of reactivity and performance of the obtained film. When the amino compound reacts with the acid halide group, an amide bond is formed between the separation function layer and the water-soluble compound, and when the alcohols react with the acid halide group, the separation function layer reacts with the water-soluble compound. An ester bond is formed between them.

Further, the water-soluble compound having at least one reactive group which reacts with the acid halide group preferably has a hydrophilic group which does not react with the acid halide group. For example, an ether group, an amide group, an ester group, a tertiary amino group,
Quaternary ammonium group, cyano group, nitro group, alkoxy group, carboxyl group, carbonyl group, keto group, alkoxycarbonyl group, amide group, cyano group, formyl group, mercapto group, imino group, alkylthio group, sulfinyl group, sulfonyl group , Sulfo group, nitroso group, phosphate group,
And a phosphorylcholine group. Particularly, an electrically neutral hydrophilic group such as an ether group, an amide group and an ester group is preferable. Further, an amphoteric charged group such as a phoscholylcholine group containing the same amount of a positively charged group and a negatively charged group is also preferable.

The compound having at least one reactive group that reacts with such an acid halide group is reacted with an unreacted acid halogen group remaining on the surface of the separation function layer to form a covalent bond and immobilize it on the membrane surface. This makes it possible to introduce a desired functional group onto the film surface, and improve the hydrophilicity of the film surface. Further, since a covalent bond is formed with the separation function layer, the durability is superior to the case where only adsorption is performed.

Next, a method for producing the semipermeable membrane of the present invention will be described.

The above-described composite semipermeable membrane is obtained by polycondensing a polyfunctional amine compound and a polyfunctional acid halide on a microporous support membrane to provide a crosslinked polyamide separation functional layer, followed by an acid halide group. It is obtained by coating the surface with an aqueous solution of a compound having at least one reactive group that reacts with the surface and forming a covalent bond with the acid-halogen group remaining on the surface of the separation function layer.

First, a polysulfone solution, for example, is cast to a certain thickness on a support such as a densely woven polyester cloth or nonwoven fabric, and is wet-solidified in water, and most of the surface has a diameter of less than A microporous support membrane having fine pores of 10 nm or less is obtained.

On the microporous support membrane thus obtained,
Polyamide having substantially separation performance by sequentially applying an aqueous solution of a polyfunctional amine compound having at least two amino groups in one molecule and a solution of a polyfunctional acid halide to cause an in-situ interfacial polycondensation reaction A separation function layer is formed.

The concentration of the aqueous solution of the polyfunctional amine compound is 0.1.
It is preferably in the range of 1 to 20% by weight,
More preferably, it is in the range of １５15% by weight. When the concentration of the polyfunctional amine compound is less than 0.1% by weight, the progress of the interfacial polycondensation reaction is slow. When the concentration exceeds 20% by weight, the thickness of the separation functional layer tends to be large, and the water permeability tends to be reduced.

The solvent for dissolving the polyfunctional acid halide is
Any material may be used as long as it is immiscible with water, dissolves the polyfunctional acid halide, does not destroy the microporous support membrane, and can form a crosslinked polymer by interfacial polycondensation. For example, hydrocarbon compounds, cyclohexane, 1,1,2-
Trichloro-1,2,2 trifluoroethane and the like are preferred.
Hexane, heptane, octane, nonane, decane, undecane, dodecane, 1,1,2-trichloro-1,
2,2 trifluoroethane and the like.

The concentration of the polyfunctional acid halide in the organic solvent is preferably in the range of 0.01 to 1% by weight. When the amount is less than 0.01% by weight, the formation of the separation function layer, which is the active layer, tends to be insufficient. When the amount exceeds 1% by weight, the concentration of carboxyl groups on the surface of the separation function layer increases, and cationic organic substances (for example, When a cationic surfactant is contained, the water permeability decreases and the cost increases.

The aqueous solution of the polyfunctional amine compound and the solution of the polyfunctional acid halide may be, if necessary, an acylation catalyst or a polyfunctional acid halide, as long as they do not hinder the reaction between the polyfunctional amine compound and the polyfunctional acid halide. A polar solvent, an acid scavenger, a surfactant, an antioxidant and the like can be contained.

Immediately after the formation of the polyamide separating function layer, an aqueous solution of a compound having at least one reactive group which reacts with an acid halide group is applied to the surface of the separating function layer. An acid halogen group,
A covalent bond is formed between the acid halide group and the reactive group that reacts, thereby changing the surface characteristics of the separation functional layer.

The term “immediately after” means a state before water or another aqueous solution is brought into contact with the separation functional layer. Normal,
After forming the separation function layer, with water or other aqueous solution,
The interfacial polycondensation reaction is stopped or the monomer remaining in the film is washed, but water or another aqueous solution is coated on the film surface before the aqueous solution of the compound having a reactive group that reacts with the acid halide group. Then, the unreacted acid halide group of the polyfunctional acid halide is hydrolyzed to generate an acid such as carboxylic acid, and cannot react with a compound having a reactive group that reacts with an acid halide group. For this reason, immediately after providing the polyamide separation functional layer, it is necessary to coat the surface with an aqueous solution of a compound having at least one reactive group that reacts with the acid halide group. In addition, since the hydrolysis of the acid halogen group proceeds even by moisture in the air, an aqueous solution of the compound having a reactive group that reacts with the acid halide group is formed within one hour after the formation of the separation functional layer even when the separation layer is not in contact with water. It is necessary to apply.

The water-soluble compounds having at least one reactive group which reacts with the acid halide group may be used alone or in combination. And these compounds are 0.1% by weight concentration.
Used as an aqueous solution of 01% to 20%. If it is less than 0.01%, the functional groups of the polyfunctional acid halide present in the separation functional layer remain unreacted, and the surface modification becomes insufficient. If it exceeds 20%, it is disadvantageous in terms of cost.

Other compounds may be mixed in the aqueous solution as needed. For example, to promote the reaction, an alkaline metal compound such as sodium carbonate, sodium hydroxide and sodium phosphate may be added, a solvent immiscible with the remaining water, a free polyfunctional acid halide and an amine. It is also preferable to add a surfactant such as sodium dodecyl sulfate or sodium benzenesulfonate in order to remove a reaction product with the compound.

The reaction is preferably carried out at 100 ° C. or lower. The temperature is more preferably 70 ° C or lower. When the reaction is carried out at 100 ° C. or higher, the membrane tends to undergo thermal contraction, and the amount of permeated water tends to decrease.

The reaction time is preferably from 10 seconds to 10 minutes. 1
If the time is less than 0 second, the reaction does not proceed sufficiently, and if the time is more than 10 minutes, the production efficiency deteriorates.

Although the composite semipermeable membrane thus obtained can be used as it is, it is preferable to remove unreacted residues by washing with water before use. 30-100 ° C
It is preferable to wash the membrane with water in the range described above to remove the remaining amino compound and the like. Further, the washing can be performed by immersing the support film in water within the above-mentioned temperature range, or by spraying such water. When the temperature of the water used falls below 30 ° C., the amino compound remains in the composite semipermeable membrane, and the amount of permeated water tends to decrease. In addition, when washing is performed at a temperature exceeding 100 ° C. in an autoclave, steam, or the like, the membrane undergoes thermal shrinkage, and the amount of permeated water also tends to decrease.

Thereafter, for example, when the pH is 6 to 13
It is also preferable to increase the exclusion rate and water permeability of the membrane by contacting it with a chlorine-containing aqueous solution within the range described above at normal pressure.

The composite semipermeable membrane of the present invention may be a flat membrane, a hollow fiber membrane, or a tubular membrane.

By using the composite semipermeable membrane of the present invention, for example, the operating pressure is in the range of 0.1 to 3 MPa,
More preferably, the composite semipermeable membrane and the fluid separation element can be used in a low region such as in the range of 0.1 to 1.5 MPa while maintaining a high permeated water amount. Since the operating pressure can be reduced, the capacity of a pump or the like to be used can be reduced, power consumption can be suppressed, and the cost of fresh water can be reduced. If the operating pressure is less than 0.1 MPa, the amount of permeated water tends to be too small,
When the value exceeds a, the power consumption of the pump and the like increases, and the membrane tends to be clogged due to fouling.

It is preferable that the amount of water permeated at an operating pressure of 1.0 MPa is 0.5 to ³ m ³ / m ² d.
When the amount of permeation of water is in the range of 0.5 to ³ m ³ / m ² d, generation of fouling can be suppressed moderately, and fresh water can be stably formed.

The sewage treated with the composite semipermeable membrane of the present invention contains a hardly biodegradable organic substance such as a surfactant, which is not completely decomposed by biological treatment. For this reason, when processing with a normal composite semipermeable membrane, the surfactant is adsorbed on the membrane surface,
The amount of permeated water decreases. However, since the composite semipermeable membrane of the present invention has been subjected to a surface treatment, it is difficult for a surfactant to be adsorbed and a decrease in the amount of permeated water is suppressed.

Here, the rate of decrease in the amount of permeated water is determined as follows. At 25 ° C., pH 6.5, using a 1,500 ppm aqueous solution of sodium chloride, permeate the membrane at an operating pressure of 1.0 MPa and filter the permeated water amount as the pre-permeated water amount,
Subsequently, 100 parts of nonionic surfactant (polyoxyethylene (10) octyl phenyl ether) was added to this evaluation solution.
When the amount of permeated water one hour after the addition was made to be ppm, the amount of permeated water is defined by the following equation.

Permeate water decrease rate = 1− (post-permeate water amount / pre-permeate water amount) The composite semipermeable membrane of the present invention preferably has a permeate water decrease rate of 0.35 or less. More preferably, it is 0.2 or less. By using such a membrane, even when the membrane comes into contact with the surfactant, the adsorption of the surfactant to the membrane surface is hardly observed, and the permeation flow rate is slightly reduced, so that a sufficient permeation flow rate can be maintained. Therefore, even when used for advanced treatment of sewage, high-quality permeated water can be stably obtained.

The composite semipermeable membrane obtained as described above can be housed in a housing to make a fluid separation element for easy handling. The fluid separation element includes, for example, a composite semipermeable membrane flat membrane, a separation liquid flow path material such as a tricot, and a supply liquid such as a plastic net around a cylindrical liquid collection tube having a large number of holes. Winding a membrane unit including a flow path material,
It is preferable that these are housed in a cylindrical housing.
Thereby, a plurality of fluid separation elements can be connected in series or in parallel to form a separation membrane module. Such a separation membrane module can be suitably used for a sewage treatment device.

Hereinafter, a sewage treatment apparatus and a sewage treatment method using the composite semipermeable membrane will be described with reference to FIG.

First, sewage, which is raw water, is introduced into a screen, sand, a preliminary aeration tank, a first settling tank, etc., and subjected to a physical treatment to remove suspended matters and fats and oils. At this time, it is also preferable to perform coagulation treatment with a coagulant or the like in order to increase the removal efficiency. Next, the raw water is introduced into an activated sludge tank or the like and subjected to biological treatment to decompose organic substances in the raw water. Thereafter, suspended substances are removed in the final sedimentation tank to obtain sewage secondary treatment water.

Subsequently, preferably, the sewage secondary treatment water is supplied to a sand filtration device, a microfiltration membrane, an ultrafiltration membrane, or the like to further remove suspended substances in the water. Here, in order to preferably remove microorganisms, it is more preferable to use a microfiltration membrane or an ultrafiltration membrane, and to remove macromolecules in raw water and reduce membrane contamination in the subsequent stage, it is preferable to use an ultrafiltration membrane. Membranes are more preferred.

In the present invention, the water subjected to such treatment is supplied to the composite semipermeable membrane module configured as described above to remove salts and organic substances in raw water. The permeated water from which salt and organic substances in the raw water have been removed can be reused as water for hydrophilic use or the like.

In the present invention, the target sewage contains a large amount of a surfactant for soap and washing drainage, and if a conventional polyamide-based composite semipermeable membrane or the like is used, the amount of permeated water is reduced at an early stage. Therefore, a compound having at least one reactive group that reacts with an acid halide group was covalently bonded to an acid halogen group remaining on the surface of the separation functional layer, and the surface of the composite half was modified. Since a permeable membrane is used, even if it comes into contact with a surfactant, almost no adsorption of the surfactant to the membrane surface is observed and the amount of permeated water is slightly reduced, so that high-quality permeated water can be stably obtained. .

Further, by treating raw water with a microfiltration membrane or an ultrafiltration membrane before supplying it to the composite semipermeable membrane of the present invention,
Since the microorganisms can be suitably removed even when the biological treatment is performed in the former stage, the latter composite semipermeable membrane module can be protected from suspended substances.

[0047]

EXAMPLES In Examples and Comparative Examples, the pH was 6.5.
The evaluation was performed under the conditions of an operating pressure of 1.0 MPa using a 1,500 ppm aqueous solution of sodium chloride.

The desalting rate was determined by the following equation.

Desalination rate (%) = (1−Salt concentration in permeate /
(Salt concentration in the supply liquid) x 100 The amount of permeated water is expressed in unit area (m ² ) per unit time (day).
It was determined by the amount of water permeating through the membrane. (Example 1) Taffeta made of polyester fiber and having a length of 30 cm and a width of 20 cm (multifilament yarn of 166 decitex for both warp and weft, woven density of 90 warp /
(Inch, width 67 / inch, thickness 160 μm) was fixed on a glass plate, and a 15% by weight dimethylformamide (DMF) solution of polysulfone was cast at a thickness of 200 μm at 25 ° C. on the glass plate. It was immersed in water and allowed to stand for 5 minutes, and then treated in hot water at 90 ° C. for 2 minutes to obtain a microporous support film (hereinafter referred to as FT-PS support film). The thickness of the FT-PS support film is 200 to 210 μm.
The pure water permeability coefficient is 0.1 MPa at a pressure of 25
° C, when measured at an ambient temperature of 25 ° C, 0.01 to 0.0
It was 3 g / cm ² · sec · atm.

The FT-PS support membrane was immersed in an aqueous solution containing 1% by weight of m-phenylenediamine and 1% by weight of ε-caprolactam for 1 minute. Next, the support film was slowly pulled up in the vertical direction to remove excess aqueous solution from the surface of the support film, and then a decane solution containing 0.06% by weight of trimesic acid chloride was applied so that the surface was completely wetted. Next, after removing the excess solution by draining the film vertically and removing the solvent remaining on the film surface, the temperature at 30 ° C. was adjusted so that the wind speed on the film surface was 8 m / s. Air was blown for one minute.

This membrane was immersed in an aqueous solution containing 1.0% by weight of polyethyleneimine and 0.3% by weight of sodium lauryl sulfate for 2 minutes. Furthermore, after immersion in hot water of 90 ° C. for 2 minutes, the film was immersed in a solution containing 500 ppm of sodium hypochlorite adjusted to pH 7 for 2 minutes to improve the film performance,
The resultant was immersed in a 1,000 ppm aqueous solution of sodium hydrogen sulfite to eliminate the remaining sodium hypochlorite, thereby obtaining a composite semipermeable membrane.

The obtained composite semipermeable membrane was evaluated under the above conditions,
The salt exclusion rate, permeated water amount, and permeated water reduction rate were measured. Table 1 shows the evaluation results. Example 2 A film was formed and evaluated in the same manner as in Example 1 except that 2-ethanolamine was used instead of polyethyleneimine. Table 1 shows the evaluation results. (Example 3) A film was formed and evaluated in the same manner as in Example 1 except that N- (3-aminopropyl) morpholine was used instead of polyethyleneimine. Table 1 shows the evaluation results. Example 4 A film was formed and evaluated in the same manner as in Example 1 except that N, N dimethyl-p-phenylenediamine was used instead of polyethyleneimine. Table 1 shows the evaluation results. Comparative Example 1 A film was formed and evaluated in the same manner as in Example 1 except that sodium carbonate was used instead of polyethyleneimine. Table 1 shows the evaluation results.

[0053]

[Table 1]

[0054]

According to the composite semipermeable membrane of the present invention, a water-soluble compound having at least one reactive group which reacts with an acid halide group is covalently bonded to an oxyhalogen group remaining on the surface of the separation functional layer. Since the surface is modified, even if it comes in contact with the surfactant, the adsorption of the surfactant to the membrane surface is hardly observed, and the decrease in the permeation flow rate is slight, so that a sufficient permeation flow rate can be maintained.
Therefore, even when used for advanced treatment of sewage, it is possible to stably obtain high quality permeated water.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a sewage treatment method using a composite semipermeable membrane of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C02F 1/44 C02F 1/44 FF term (Reference) 4D006 GA03 KA02 KA52 KB13 KB15 KB21 MA01 MA02 MA03 MA09 MA10 MA25 MA27 MA31 MB01 MB09 MB14 MC54X MC71X NA45 NA60 PB04 PB08 PC61 PC62

Claims (9)

[Claims] 1. A composite half for sewage, wherein a crosslinked polyamide separation functional layer is formed on a microporous support membrane, and a water-soluble compound forms a covalent bond with the surface of the separation functional layer. Permeable membrane. 2. The composite semipermeable membrane for sewage according to claim 1, wherein the covalent bond is an amide bond. 3. The composite semipermeable membrane for sewage according to claim 1, wherein the covalent bond is an ester bond. 4. NaCl, pH 6.5 at 25 ° C.
An aqueous solution having a concentration of 1,500 mg / l
The amount of permeated water when filtered at the pressure of 1 hour and filtered for 1 hour is defined as F1, and then the permeation at the time of adding the polyoxyethylene (10) octyl phenyl ether to the aqueous solution so as to have a concentration of 100 mg / l and filtering for 1 hour. The composite semipermeable membrane for sewage according to any one of claims 1 to 3, wherein the value of 1- (F2 / F1) is 0.35 or less when the amount of water is F2. 5. NaCl, pH 6.5 at 25 ° C.
An aqueous solution having a concentration of 1,500 mg / l
The amount of permeated water when filtered at an
Sewage composite semipermeable membrane according to any one of claims 1 to 4 to 3M is a ³ / m ² d. 6. A sewage treatment apparatus having the composite semipermeable membrane for sewage according to claim 1. 7. A polyfunctional amine compound and a polyfunctional acid halide are polycondensed to provide a polyamide separation function layer on a microporous support membrane, and then at least one reactive group reacting with an acid halide group is provided. An aqueous solution of the compound having the compound on the surface of the polyamide separation function layer, and forming a covalent bond between the acid halide group remaining on the surface of the separation function layer and the reactive group. A method for manufacturing a permeable membrane. 8. A sewage treatment method comprising treating sewage using the composite semipermeable membrane according to claim 1 or the composite semipermeable membrane produced by the method according to claim 7. 9. The sewage treatment method according to claim 8, wherein the sewage after the treatment with the microfiltration membrane or the ultrafiltration membrane is supplied to the composite semipermeable membrane.