JP5050335B2 - Manufacturing method of composite semipermeable membrane - Google Patents
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本発明は、液状混合物の選択分離に有用な複合半透膜の製造方法に関し、特に高脱塩性と高透水性とをあわせ持ち海水やかん水の脱塩にあたって好適に用いることができる、微多孔性支持膜上にポリアミド分離機能層を形成した複合半透膜の製造方法に関する。 The present invention relates to a method for producing a composite semipermeable membrane useful for selective separation of a liquid mixture, and particularly has a high desalting property and a high water permeability, and can be suitably used for desalting seawater and brine. The present invention relates to a method for producing a composite semipermeable membrane in which a polyamide separation functional layer is formed on a conductive support membrane.
複合半透膜は、液状混合物の成分を選択的に分離するものであり、超純水の製造、海水またはかん水の脱塩、染色や電着塗料廃水の除去・分離回収による工業用水のクローズドシステム構築、食品工業での有効成分の濃縮等に用いられている。 The composite semipermeable membrane selectively separates the components of the liquid mixture, and is a closed system for industrial water by producing ultrapure water, desalting seawater or brine, and removing / separating dyeing and electrodeposition paint wastewater. It is used for construction and concentration of active ingredients in the food industry.
具体的な複合半透膜としては、多官能アミンと多官能酸誘導体（例えば塩化物）との界面重縮合反応によって得られる架橋ポリアミドからなる薄膜層を多孔性支持膜上に形成させた複合半透膜があり、これは、透水性や選択分離性の高い逆浸透膜として注目されている（例えば、特開昭５５−１４７０６号公報、特開平５−７６７４０号公報など参照）。 As a specific composite semipermeable membrane, a composite semipermeable membrane in which a thin film layer made of a crosslinked polyamide obtained by interfacial polycondensation reaction between a polyfunctional amine and a polyfunctional acid derivative (eg, chloride) is formed on a porous support membrane. There is a permeable membrane, which is attracting attention as a reverse osmosis membrane having high water permeability and high selective separation (see, for example, JP-A Nos. 55-14706 and 5-76740).
また、高透水性を発現するために、界面重縮合反応で添加剤を用いて製造する逆浸透膜も開発されている。該添加剤としては、水酸化カリウムやリン酸三ナトリウムなど界面反応にて生成する酸性物質を系外に除去するための化合物や、アシル化触媒、溶解度パラメーターが８〜１４（ｃａｌ／ｃｍ2）0.5の化合物などが提案されている（例えば、特開昭６３−１２３１０号公報、特開平６−４７２６０号公報、特開平９−８５０６８号公報、特開２００１−１７９０６１号公報など参照）。 Moreover, in order to express high water permeability, the reverse osmosis membrane manufactured using an additive by interfacial polycondensation reaction is also developed. Examples of the additive include a compound for removing an acidic substance generated by an interfacial reaction such as potassium hydroxide and trisodium phosphate out of the system, an acylation catalyst, and a solubility parameter of 8 to 14 (cal / cm 2 ). A compound of 0.5 or the like has been proposed (see, for example, JP-A-63-12310, JP-A-6-47260, JP-A-9-85068, JP-A-2001-179061).
また、脱塩性能を向上させる手段としては複合半透膜を無機塩を含む水溶液と接触処理する方法が提案されている（特開２００３−１１７３６１号公報など）。 Further, as a means for improving the desalting performance, a method of contacting the composite semipermeable membrane with an aqueous solution containing an inorganic salt has been proposed (Japanese Patent Application Laid-Open No. 2003-117361).
しかしながら、これら従来技術による製膜方法によって実用上十分な性能の複合半透膜を製造しようとする場合、製膜の際に使用する多官能アミン水溶液には、ある程度以上の多官能アミン濃度が必要であり、多官能アミン濃度を低減させることは困難と考えられていた。例えば、多官能アミン濃度が２重量％以下の水溶液を用いて製造した場合、２５℃、ｐＨ６．５、ＴＤＳ濃度３．５重量％の海水を５．５ＭＰａの操作圧力で透過させたときに、透過流束が０．６ｍ３／ｍ２・日以上１．２ｍ３／ｍ２・日以下、脱塩率９９．７％以上、溶質透過係数が１．５×１０−８ｍ／ｓ以下の性能を満足させることはできなかった。また、多官能アミン濃度が１重量％以下の水溶液を用いて製造した場合、２５℃、ｐＨ６．５、１５００ｐｐｍの塩化ナトリウム水溶液を１．５ＭＰａの操作圧力で透過させたときに、透過流束が１ｍ３／ｍ２・日以上１．５ｍ３／ｍ２・日以下、塩化ナトリウム除去率９９．３％以上、溶質透過係数が２．０×１０−８ｍ／ｓ以下の性能を満足させることはできなかった。 However, when a composite semipermeable membrane having practically sufficient performance is to be produced by these conventional film forming methods, the polyfunctional amine aqueous solution used for film formation needs a polyfunctional amine concentration of a certain level or more. Therefore, it was considered difficult to reduce the polyfunctional amine concentration. For example, when manufactured using an aqueous solution having a polyfunctional amine concentration of 2% by weight or less, when seawater at 25 ° C., pH 6.5, TDS concentration 3.5% by weight is permeated at an operating pressure of 5.5 MPa, The permeation flux is 0.6 m 3 / m 2 · day or more and 1.2 m 3 / m 2 · day or less, the desalination rate is 99.7% or more, and the solute permeability coefficient is 1.5 × 10 −8 m / s or less. The performance could not be satisfied. In addition, when manufactured using an aqueous solution having a polyfunctional amine concentration of 1% by weight or less, when a sodium chloride aqueous solution at 25 ° C., pH 6.5, 1500 ppm is permeated at an operating pressure of 1.5 MPa, the permeation flux is Satisfy the performance of 1 m 3 / m 2 · day or more and 1.5 m 3 / m 2 · day or less, sodium chloride removal rate of 99.3% or more, and solute permeability coefficient of 2.0 × 10 −8 m / s or less. I couldn't.
ところで、実用上十分な性能の複合半透膜を工業的に製造する際には、その製造コストを低減化させるために、製膜の際に使用する多官能アミン水溶液の多官能アミン濃度を低減させることが望まれているが、上述したとおり、従来方法では、複合半透膜の性能を低下させずに多官能アミン濃度を低減させることは困難であった。 By the way, when industrially producing a composite semipermeable membrane with practically sufficient performance, the polyfunctional amine concentration of the polyfunctional amine aqueous solution used for film formation is reduced in order to reduce the production cost. However, as described above, it has been difficult to reduce the polyfunctional amine concentration without reducing the performance of the composite semipermeable membrane as described above.
本発明は、かかる従来技術の欠点を解消しようとするものであり、複合半透膜の性能を低下させることなく従来に比べ使用する多官能アミンの量を低減させることができる、実用性のある脱塩が可能な複合半透膜の製造方法の提供を目的とし、また、従来と同等のアミン量を使用した場合では、複合半透膜の溶質透過係数を低下させることができる複合半透膜の製造方法の提供を目的とする。 The present invention is intended to eliminate the drawbacks of the prior art, and can reduce the amount of polyfunctional amine used compared to the prior art without degrading the performance of the composite semipermeable membrane. The purpose of the present invention is to provide a method for producing a composite semipermeable membrane capable of desalting, and when using the same amount of amine as in the past, the composite semipermeable membrane can reduce the solute permeability coefficient of the composite semipermeable membrane. It aims at providing the manufacturing method of this.
上記目的を達成するための本発明は、微多孔性支持膜上に多官能アミン水溶液を接触させた後、多官能酸ハロゲン化物を含む、水と非混和性の有機溶媒溶液を接触させ、界面重縮合によって微多孔性支持膜上に架橋ポリアミドを含む分離機能層を形成する複合半透膜の製造方法において、上記多官能アミン水溶液中に中性無機塩を０．５重量％以上含有させることを特徴とする複合半透膜の製造方法である。 In order to achieve the above object, the present invention comprises contacting a water-immiscible organic solvent solution containing a polyfunctional acid halide after contacting a polyfunctional amine aqueous solution on a microporous support membrane, In the method for producing a composite semipermeable membrane in which a separation functional layer containing a crosslinked polyamide is formed on a microporous support membrane by polycondensation, the polyfunctional amine aqueous solution contains 0.5% by weight or more of a neutral inorganic salt. Is a method for producing a composite semipermeable membrane.
本発明法によれば、使用する多官能アミンの量を低減させて複合半透膜を製造した場合でも、実用性のある高脱塩率、高透過流束を達成できる複合半透膜が得られるので、アミン使用量低減によるコストの削減を図ることができる。また、従来と同等のアミン量を使用した場合では、溶質透過係数を低下させることができる。本発明法による複合半透膜は、海水またはかん水の脱塩、染色や電着塗料廃水の除去・分離回収による工業用水のクローズドシステム構築、食品工業での有効成分の濃縮等に好適に用いることができる。 According to the method of the present invention, even when a composite semipermeable membrane is produced by reducing the amount of polyfunctional amine to be used, a composite semipermeable membrane capable of achieving a practical high desalination rate and high permeation flux is obtained. Therefore, the cost can be reduced by reducing the amount of amine used. Moreover, when the amine amount equivalent to the conventional one is used, the solute permeability coefficient can be lowered. The composite semipermeable membrane according to the method of the present invention is suitably used for desalination of seawater or brine, construction of industrial water closed system by dyeing and removal / separation recovery of electrodeposition paint wastewater, concentration of active ingredients in food industry, etc. Can do.
本発明法で製造する複合半透膜は、微多孔性支持膜上に中性無機塩を含有する多官能アミン水溶液を接触させた後、多官能酸ハロゲン化物を含む、水と非混和性の有機溶媒溶液を接触させ、界面重縮合によって微多孔性支持膜の少なくとも片面に架橋ポリアミドを含む分離機能層が設けられた構造の複合半透膜が好ましい。分離機能層は微多孔性支持膜の両面に設けられても良く、複数の分離機能層を設けても良いが、通常、片面に１層の分離機能層があれば十分である。 The composite semipermeable membrane produced by the method of the present invention is contacted with a polyfunctional amine aqueous solution containing a neutral inorganic salt on a microporous support membrane, and then contains a polyfunctional acid halide and is immiscible with water. A composite semipermeable membrane having a structure in which an organic solvent solution is brought into contact and a separation functional layer containing a crosslinked polyamide is provided on at least one surface of the microporous support membrane by interfacial polycondensation is preferable. The separation functional layer may be provided on both surfaces of the microporous support membrane, or a plurality of separation functional layers may be provided. However, it is usually sufficient to have one separation functional layer on one surface.
分離機能層の厚みは、十分な分離性能および透過水量を得るために、通常０．０１〜１μｍの範囲内、好ましくは０．１〜０．５μｍの範囲内である。 The thickness of the separation functional layer is usually in the range of 0.01 to 1 μm, preferably in the range of 0.1 to 0.5 μm, in order to obtain sufficient separation performance and permeated water amount.
ここで、多官能アミンとは、一分子中に少なくとも２個の一級および／または二級アミノ基を有するアミンをいい、例えば、２個のアミノ基がオルト位やメタ位、パラ位のいずれかの位置関係でベンゼンに結合したフェニレンジアミン、キシリレンジアミン、１，３，５−トリアミノベンゼン、１，２，４−トリアミノベンゼン、３，５−ジアミノ安息香酸などの芳香族多官能アミン、エチレンジアミン、プロピレンジアミンなどの脂肪族アミン、１，２−ジアミノシクロヘキサン、１，４−ジアミノシクロヘキサン、ピペラジン、１，３−ビスピペリジルプロパン、４−アミノメチルピペラジンなどの脂環式多官能アミン等を挙げることができる。中でも、膜の選択分離性や透過性、耐熱性を考慮すると一分子中に２〜４個の一級および／または二級アミノ基を有する芳香族多官能アミンであることが好ましく、このような多官能芳香族アミンとしては、ｍ−フェニレンジアミン、ｐ−フェニレンジアミン、１，３，５−トリアミノベンゼンが好適に用いられる。中でも、入手の容易性や取り扱いのしやすさから、ｍ−フェニレンジアミンを用いることがより好ましい。これらの多官能アミンは、単独で用いたり、混合して用いてもよい。 Here, the polyfunctional amine refers to an amine having at least two primary and / or secondary amino groups in one molecule. For example, two amino groups are any of ortho, meta, and para positions. Aromatic polyfunctional amines such as phenylenediamine, xylylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene and 3,5-diaminobenzoic acid bonded to benzene in the positional relationship of Aliphatic amines such as ethylenediamine and propylenediamine, alicyclic polyfunctional amines such as 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 1,3-bispiperidylpropane and 4-aminomethylpiperazine be able to. Of these, aromatic polyfunctional amines having 2 to 4 primary and / or secondary amino groups in one molecule are preferred in consideration of selective separation, permeability, and heat resistance of the membrane. As the functional aromatic amine, m-phenylenediamine, p-phenylenediamine, and 1,3,5-triaminobenzene are preferably used. Among these, it is more preferable to use m-phenylenediamine from the standpoint of availability and ease of handling. These polyfunctional amines may be used alone or in combination.
本発明における中性無機塩とは、水に０．５重量％以上溶解し、ｐＨが５〜９の範囲のものであれば問題なく、例えばアルカリ金属塩、アルカリ土類金属塩、遷移金属塩などが挙げられる。好ましくはナトリウム塩、リチウム塩、カルシウム塩およびマグネシウム塩から選ばれる少なくとも１種である。このような中性無機塩としては、塩化ナトリウム、塩化リチウム、塩化カルシウム、塩化マグネシウムなどが好適に用いられるが、中でも、入手の容易性や試薬のコスト、取扱い性の面から、塩化ナトリウムを用いることが好ましい。これらの中性無機塩は、単独で用いたり、混合して用いてもよい。 The neutral inorganic salt in the present invention is no problem as long as it is dissolved in water by 0.5% by weight or more and has a pH in the range of 5 to 9, for example, alkali metal salts, alkaline earth metal salts, transition metal salts. Etc. Preferably, it is at least one selected from sodium salt, lithium salt, calcium salt and magnesium salt. As such a neutral inorganic salt, sodium chloride, lithium chloride, calcium chloride, magnesium chloride, and the like are preferably used. Among them, sodium chloride is used from the viewpoint of easy availability, reagent cost, and handleability. It is preferable. These neutral inorganic salts may be used alone or in combination.
また、多官能酸ハロゲン化物とは、一分子中に少なくとも２個のハロゲン化カルボニル基を有する酸ハロゲン化物をいう。例えば、３官能酸ハロゲン化物では、トリメシン酸クロリド、１，３，５−シクロヘキサントリカルボン酸トリクロリド、１，２，４−シクロブタントリカルボン酸トリクロリドなどを挙げることができ、２官能酸ハロゲン化物では、ビフェニルジカルボン酸ジクロリド、アゾベンゼンジカルボン酸ジクロリド、テレフタル酸クロリド、イソフタル酸クロリド、ナフタレンジカルボン酸クロリドなどの芳香族２官能酸ハロゲン化物、アジポイルクロリド、セバコイルクロリドなどの脂肪族２官能酸ハロゲン化物、シクロペンタンジカルボン酸ジクロリド、シクロヘキサンジカルボン酸ジクロリド、テトラヒドロフランジカルボン酸ジクロリドなどの脂環式２官能酸ハロゲン化物を挙げることができる。多官能アミンとの反応性を考慮すると、多官能酸ハロゲン化物は多官能酸塩化物であることが好ましく、また、膜の選択分離性、耐熱性を考慮すると、一分子中に２〜４個の塩化カルボニル基を有する多官能芳香族酸塩化物であることが好ましい。中でも、入手の容易性や取り扱いのしやすさの観点から、トリメシン酸クロリドを用いるとより好ましい。これらの多官能酸ハロゲン化物は、単独で用いたり、混合して用いてもよい。 The polyfunctional acid halide refers to an acid halide having at least two carbonyl halide groups in one molecule. Examples of trifunctional acid halides include trimesic acid chloride, 1,3,5-cyclohexanetricarboxylic acid trichloride, 1,2,4-cyclobutanetricarboxylic acid trichloride, and bifunctional acid halides include biphenyl dicarboxylic acid. Aromatic difunctional acid halides such as acid dichloride, azobenzene dicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, naphthalene dicarboxylic acid chloride, aliphatic difunctional acid halides such as adipoyl chloride, sebacoyl chloride, cyclopentane Examples thereof include alicyclic difunctional acid halides such as dicarboxylic acid dichloride, cyclohexane dicarboxylic acid dichloride, and tetrahydrofuran dicarboxylic acid dichloride. Considering the reactivity with the polyfunctional amine, the polyfunctional acid halide is preferably a polyfunctional acid chloride, and considering the selective separation property and heat resistance of the membrane, 2 to 4 per molecule. The polyfunctional aromatic acid chloride having a carbonyl chloride group is preferred. Among them, it is more preferable to use trimesic acid chloride from the viewpoint of easy availability and easy handling. These polyfunctional acid halides may be used alone or in combination.
本発明における複合半透膜は、海水やかん水の脱塩に用いられるものである。海水脱塩用途に用いるには２５℃、ｐＨ６．５、ＴＤＳ濃度３．５重量％の海水を５．５ＭＰａの操作圧力で透過させたときに、透過流束が０．６ｍ３／ｍ２・日以上１．２ｍ３／ｍ２・日以下、脱塩率９９．７％以上、溶質透過係数が１．５×１０−８ｍ／ｓ以下であることが好ましい。一方、かん水脱塩用途に用いるには２５℃、ｐＨ６．５、１５００ｐｐｍの塩化ナトリウム水溶液を１．５ＭＰａの操作圧力で透過させたときに、透過流束が１ｍ３／ｍ２・日以上１．５ｍ３／ｍ２・日以下、塩化ナトリウム除去率９９．３％以上、溶質透過係数が２．０×１０−８ｍ／ｓ以下であることが好ましい。 The composite semipermeable membrane in the present invention is used for desalting seawater and brine. When used for seawater desalination, when the seawater of 25 ° C, pH 6.5, TDS concentration 3.5 wt% is permeated at an operating pressure of 5.5 MPa, the permeation flux is 0.6 m 3 / m 2 · It is preferable that it is not less than 1.2 m 3 / m 2 · day, not less than 99.7% and not more than 1.5 × 10 −8 m / s. On the other hand, when used for brine desalination, a permeation flux of 1 m 3 / m 2 · day or more is obtained when a sodium chloride aqueous solution at 25 ° C., pH 6.5 and 1500 ppm is permeated at an operating pressure of 1.5 MPa. 5 m 3 / m 2 · day or less, sodium chloride removal rate of 99.3% or more, and solute permeability coefficient of 2.0 × 10 −8 m / s or less are preferable.
微多孔性支持膜上にポリアミド分離機能層を形成するには、中性無機塩を含有する多官能アミン水溶液と、多官能酸ハロゲン化物の有機溶媒溶液とを微多孔性支持膜上で接触させ界面重縮合させればよい。 In order to form a polyamide separation functional layer on a microporous support membrane, a polyfunctional amine aqueous solution containing a neutral inorganic salt and a polyfunctional acid halide organic solvent solution are contacted on the microporous support membrane. Interfacial polycondensation may be performed.
ポリアミド分離機能層を、中性無機塩を含有する多官能アミン水溶液と、多官能酸ハロゲン化物の有機溶媒溶液とを微多孔性支持膜上で接触させ界面重縮合させることにより形成させてなる複合半透膜は、多官能アミン水溶液濃度が２重量％以下の場合でも、２５℃、ｐＨ６．５、ＴＤＳ濃度３．５重量％の海水を５．５ＭＰａの操作圧力で透過させたときに、透過流束が０．６ｍ３／ｍ２・日以上１．２ｍ３／ｍ２・日以下、脱塩率９９．７％以上、溶質透過係数が１．５×１０−８ｍ／ｓ以下の膜性能を得ることができ、また、多官能アミン濃度が１重量％以下の場合でも、２５℃、ｐＨ６．５、１５００ｐｐｍの塩化ナトリウム水溶液を１．５ＭＰａの操作圧力で透過させたときに、透過流束が１ｍ３／ｍ２・日以上１．５ｍ３／ｍ２・日以下、塩化ナトリウム除去率９９．３％以上、溶質透過係数が２．０×１０−８ｍ／ｓ以下の膜性能を示すことができる。 A composite formed by forming a polyamide separation functional layer by interfacial polycondensation by bringing a polyfunctional amine aqueous solution containing a neutral inorganic salt into contact with an organic solvent solution of a polyfunctional acid halide on a microporous support membrane. Even when the concentration of the polyfunctional amine aqueous solution is 2% by weight or less, the semipermeable membrane permeates when seawater at 25 ° C., pH 6.5, and TDS concentration of 3.5% by weight is permeated at an operating pressure of 5.5 MPa. Membrane having a flux of 0.6 m 3 / m 2 · day or more and 1.2 m 3 / m 2 · day or less, a desalination rate of 99.7% or more, and a solute permeability coefficient of 1.5 × 10 -8 m / s or less Performance can be obtained, and even when the polyfunctional amine concentration is 1% by weight or less, when a sodium chloride aqueous solution at 25 ° C., pH 6.5 and 1500 ppm is permeated at an operating pressure of 1.5 MPa, 1.5m bundle is 1m 3 / m 2 · day or more / M 2 · day or less, sodium chloride removal rate 99.3% or more, solute transmission coefficient can be shown the following membrane performance 2.0 × 10 -8 m / s.
なお、溶質の透過係数は以下の方法により求めることができる。非平衡熱力学に基づいた逆浸透法の輸送方程式として、以下の式が知られている。 The solute permeability coefficient can be determined by the following method. The following equation is known as a transport equation of the reverse osmosis method based on non-equilibrium thermodynamics.
Ｊｖ＝Ｌｐ（ΔＰ−σ・Δπ） （１）
Ｊｓ＝Ｐ（Ｃｍ−Ｃｐ）＋（１−σ）Ｃ・Ｊｖ （２）
Jv = Lp (ΔP−σ · Δπ) (1)
Js = P (Cm−Cp) + (1−σ) C · Jv (2)
ここで、Ｊｖは膜透過体積流束（ｍ３／ｍ２／ｓ）、Ｌｐは純水透過係数（ｍ３／ｍ２／ｓ／Ｐａ）、ΔＰは膜両側の圧力差（Ｐａ）、σは溶質反射係数、Δπは膜両側の浸透圧差（Ｐａ）、Ｊｓは溶質の膜透過流束（ｍｏｌ／ｍ２／ｓ）、Ｐは溶質の透過係数（ｍ／ｓ）、Ｃｍは溶質の膜面濃度（ｍｏｌ／ｍ３）、Ｃｐは透過液濃度（ｍｏｌ／ｍ３）、Ｃは膜両側の濃度（ｍｏｌ／ｍ３）、である。膜両側の平均濃度Ｃは、逆浸透膜のように両側の濃度差が非常に大きな場合には実質的な意味を持たない。そこで（２）式を膜厚について積分した次式がよく用いられる。 Here, Jv is the membrane permeation volume flux (m 3 / m 2 / s), Lp is the pure water permeability coefficient (m 3 / m 2 / s / Pa), ΔP is the pressure difference (Pa) on both sides of the membrane, σ Is the solute reflection coefficient, Δπ is the osmotic pressure difference (Pa) on both sides of the membrane, Js is the solute permeation flux (mol / m 2 / s), P is the solute permeability (m / s), and Cm is the solute membrane. The surface concentration (mol / m 3 ), Cp is the permeate concentration (mol / m 3 ), and C is the concentration on both sides of the membrane (mol / m 3 ). The average concentration C on both sides of the membrane has no substantial meaning when the concentration difference between the two sides is very large as in a reverse osmosis membrane. Therefore, the following equation obtained by integrating equation (2) with respect to the film thickness is often used.
Ｒ＝σ（１−Ｆ）／（１−σＦ） （３）
ただし、
Ｆ＝ｅｘｐ｛−（１−σ）Ｊｖ／Ｐ｝ （４）
であり、Ｒは真の阻止率で、
Ｒ＝１−Ｃｐ／Ｃｍ （５）
で定義される。
R = σ (1-F) / (1-σF) (3)
However,
F = exp {− (1−σ) Jv / P} (4)
Where R is the true rejection rate
R = 1-Cp / Cm (5)
Defined by
ΔＰを種々変化させることにより（１）式からＬｐを算出でき、またＪｖを種々変化させてＲを測定し、Ｒと１／Ｊｖをプロットしたものに対して（３）、（４）式をカーブフィッティングすることにより、Ｐとσを同時に求めることができる。 By changing ΔP in various ways, Lp can be calculated from the equation (1), R is measured by changing Jv in various ways, and R and 1 / Jv are plotted against the equations (3) and (4). P and σ can be obtained simultaneously by curve fitting.
本発明において微多孔性支持膜は、実質的にイオン等の分離性能を有さず、実質的に分離性能を有する分離機能層に強度を与えるためのものである。孔のサイズや分布は特に限定されないが、例えば、均一で微細な孔、あるいは分離機能層が形成される側の表面からもう一方の面まで徐々に大きな微細孔をもち、かつ、分離機能層が形成される側の表面で微細孔の大きさが０．１ｎｍ以上１００ｎｍ以下であるような支持膜が好ましい。 In the present invention, the microporous support membrane is intended to give strength to a separation functional layer that substantially does not have separation performance of ions or the like and has substantial separation performance. The size and distribution of the pores are not particularly limited. For example, the pores have uniform and fine pores or gradually have large pores from the surface on the side where the separation functional layer is formed to the other surface, and the separation functional layer has A support film having a micropore size of 0.1 nm or more and 100 nm or less on the surface to be formed is preferable.
微多孔性支持膜に使用する材料やその形状は特に限定されないが、例えばポリエステルまたは芳香族ポリアミドから選ばれる少なくとも一種を主成分とする布帛により強化されたポリスルホンや酢酸セルロースやポリ塩化ビニル、あるいはそれらを混合したものが好ましく使用される。使用される素材としては、化学的、機械的、熱的に安定性の高いポリスルホンを使用するのが特に好ましい。 The material used for the microporous support membrane and the shape thereof are not particularly limited. For example, polysulfone, cellulose acetate, polyvinyl chloride reinforced with a fabric mainly composed of at least one selected from polyester or aromatic polyamide, or those A mixture of these is preferably used. As a material to be used, it is particularly preferable to use polysulfone having high chemical, mechanical and thermal stability.
具体的には、次の化学式に示す繰り返し単位からなるポリスルホンを用いると、孔径が制御しやすく、寸法安定性が高いため好ましい。
例えば、上記ポリスルホンのＮ，Ｎ−ジメチルホルムアミド溶液を、密に織ったポリエステル布あるいは不織布の上に一定の厚さに注型し、それを水中で湿式凝固させることによって、表面の大部分が直径数１０ｎｍ以下の微細な孔を有した微多孔性支持膜を得ることができる。 For example, the N, N-dimethylformamide solution of polysulfone is cast to a certain thickness on a densely woven polyester or nonwoven fabric, and is wet-solidified in water, so that most of the surface has a diameter. A microporous support membrane having fine pores of several tens of nm or less can be obtained.
上記の多孔質支持体および基材の厚みは、複合半透膜の強度およびそれをエレメントにしたときの充填密度に影響を与える。十分な機械的強度および充填密度を得るためには、５０〜３００μｍの範囲内にあることが好ましく、より好ましくは１００〜２５０μｍの範囲内である。また、多孔質支持体の厚みは、１０〜２００μｍの範囲内にあることが好ましく、より好ましくは３０〜１００μｍの範囲内である。 The thickness of the porous support and the substrate described above affects the strength of the composite semipermeable membrane and the packing density when it is used as an element. In order to obtain sufficient mechanical strength and packing density, it is preferably in the range of 50 to 300 μm, more preferably in the range of 100 to 250 μm. Moreover, it is preferable that the thickness of a porous support body exists in the range of 10-200 micrometers, More preferably, it exists in the range of 30-100 micrometers.
多孔質支持膜形態は、走査型電子顕微鏡や透過型電子顕微鏡、原子間顕微鏡により観察できる。例えば走査型電子顕微鏡で観察するのであれば基材から多孔質支持体を剥がした後、これを凍結割断法で切断して断面観察のサンプルとする。このサンプルに白金または白金−パラジウムまたは四塩化ルテニウム、好ましくは四塩化ルテニウムを薄くコーティングして３〜６ｋＶの加速電圧で高分解能電界放射型走査電子顕微鏡（ＵＨＲ−ＦＥ−ＳＥＭ）で観察する。高分解能電界放射型走査電子顕微鏡は、日立製Ｓ−９００型電子顕微鏡などが使用できる。得られた電子顕微鏡写真から多孔質支持体の膜厚や表面孔径を決定する。なお、本発明における厚みや孔径は平均値を意味するものである。 The form of the porous support film can be observed with a scanning electron microscope, a transmission electron microscope, or an atomic microscope. For example, when observing with a scanning electron microscope, the porous support is peeled off from the substrate, and then cut by a freeze cleaving method to obtain a sample for cross-sectional observation. The sample is thinly coated with platinum, platinum-palladium, or ruthenium tetrachloride, preferably ruthenium tetrachloride, and observed with a high-resolution field emission scanning electron microscope (UHR-FE-SEM) at an acceleration voltage of 3 to 6 kV. A Hitachi S-900 electron microscope or the like can be used as the high-resolution field emission scanning electron microscope. The film thickness and surface pore diameter of the porous support are determined from the obtained electron micrograph. In addition, the thickness and the hole diameter in this invention mean an average value.
次に、本発明の複合半透膜の製造方法について、その工程順に説明する。 Next, the manufacturing method of the composite semipermeable membrane of this invention is demonstrated in the order of the process.
本発明法で得られる複合半透膜を構成する分離機能層は、前述の中性無機塩を含有する多官能アミン水溶液と、多官能酸ハロゲン化物を含有する、水と非混和性の有機溶媒溶液とを用い、微多孔性支持膜の表面で界面重縮合を行うことによりその骨格が形成される。 The separation functional layer constituting the composite semipermeable membrane obtained by the method of the present invention comprises a water-immiscible organic solvent containing a polyfunctional amine aqueous solution containing a neutral inorganic salt as described above, and a polyfunctional acid halide. The skeleton is formed by performing interfacial polycondensation on the surface of the microporous support membrane using a solution.
ここで、多官能アミン水溶液における多官能アミンの濃度は海水脱塩用途では１〜１０重量％の範囲内であることが好ましく、さらに好ましくは１．５〜５重量％の範囲内である。また、かん水脱塩用途では０．３〜１０重量％の範囲内であることが好ましく、さらに好ましくは０．５〜３重量％の範囲内である。本発明法によれば従来に比べて多官能アミン濃度が低い場合でも、十分な脱塩性能および透水性能を得ることができるので、海水脱塩用途で多官能アミン濃度を２重量％以下とすることもでき、また、かん水脱塩用途で多官能アミン濃度を１重量％以下とすることもできる。 Here, the concentration of the polyfunctional amine in the polyfunctional amine aqueous solution is preferably in the range of 1 to 10% by weight and more preferably in the range of 1.5 to 5% by weight for seawater desalination. In addition, it is preferably in the range of 0.3 to 10% by weight, more preferably in the range of 0.5 to 3% by weight for use in brine desalination. According to the method of the present invention, sufficient desalting performance and water permeation performance can be obtained even when the polyfunctional amine concentration is lower than the conventional one. Therefore, the polyfunctional amine concentration is set to 2% by weight or less for seawater desalination. It is also possible to reduce the polyfunctional amine concentration to 1% by weight or less for brine desalination.
また、多官能アミン水溶液中における中性無機塩の濃度は０．５重量％〜飽和濃度の範囲内であることが好ましい。この範囲であるとアミン濃度を低減した場合でも十分な脱塩性能および透水性能を得ることができる。中性無機塩添加による脱塩率の向上は、塩類の添加によって多量に生じたイオンが水和することにより、溶媒の活量が減少し、多官能アミンの溶解度を低下させるため、多官能アミンの濃度が高い場合と同様の効果が得られ脱塩性能の高い膜が得られるためと考えられる。水に溶解した場合のｐＨが５未満または９を超える無機塩を添加すると、別途アミン水溶液や複合半透膜洗浄廃液のｐＨ調整作業が必要になり試薬コストがかかる上、作業も繁雑になるため好ましくない。 Moreover, it is preferable that the density | concentration of the neutral inorganic salt in polyfunctional amine aqueous solution exists in the range of 0.5 weight%-saturation concentration. Within this range, sufficient desalting performance and water permeation performance can be obtained even when the amine concentration is reduced. The increase in the desalination rate by adding neutral inorganic salt is due to the hydration of ions generated in large quantities due to the addition of salts, thereby reducing the activity of the solvent and lowering the solubility of the polyfunctional amine. This is probably because the same effect as in the case where the concentration of the solution is high and a membrane having high desalting performance can be obtained. If an inorganic salt having a pH of less than 5 or more than 9 when dissolved in water is added, pH adjustment work for the aqueous amine solution or composite semipermeable membrane cleaning waste liquid is required, and the reagent cost is increased and the work becomes complicated. It is not preferable.
多官能アミン水溶液には、多官能アミンと多官能酸ハロゲン化物との反応を妨害しないものであれば、界面活性剤や有機溶媒、アルカリ性化合物、酸化防止剤などが含まれていてもよい。界面活性剤は、多孔性支持膜表面の濡れ性を向上させ、アミン水溶液と非極性溶媒との間の界面張力を減少させる効果があり、有機溶媒は界面重縮合反応の触媒として働くことがあり、添加することにより界面重宿合反応を効率よく行える場合がある。 As long as the polyfunctional amine aqueous solution does not interfere with the reaction between the polyfunctional amine and the polyfunctional acid halide, a surfactant, an organic solvent, an alkaline compound, an antioxidant, or the like may be contained. The surfactant has the effect of improving the wettability of the porous support membrane surface and reducing the interfacial tension between the aqueous amine solution and the nonpolar solvent, and the organic solvent may act as a catalyst for the interfacial polycondensation reaction. In some cases, the interfacial double reaction can be efficiently performed by adding them.
界面重縮合を多孔性支持膜上で行うために、まず、上述の中性無機塩を含有する多官能アミン水溶液を多孔性支持膜に接触させる。接触は、多孔性支持膜面上に均一にかつ連続的に行うことが好ましい。具体的には、例えば、多官能アミン水溶液を多孔性支持膜にコーティングする方法や多孔性支持膜を多官能アミン水溶液に浸漬する方法を挙げることができる。多孔性支持膜と多官能アミン水溶液との接触時間は、１〜１０分間の範囲内であることが好ましく、１〜３分間の範囲内であるとさらに好ましい。 In order to perform interfacial polycondensation on the porous support membrane, first, the polyfunctional amine aqueous solution containing the neutral inorganic salt described above is brought into contact with the porous support membrane. The contact is preferably performed uniformly and continuously on the porous support membrane surface. Specific examples include a method of coating a porous support membrane with a polyfunctional amine aqueous solution and a method of immersing the porous support membrane in a polyfunctional amine aqueous solution. The contact time between the porous support membrane and the polyfunctional amine aqueous solution is preferably in the range of 1 to 10 minutes, and more preferably in the range of 1 to 3 minutes.
多官能アミン水溶液を多孔性支持膜に接触させたあとは、膜上に液滴が残らないように十分に液切りする。十分に液切りすることで、膜形成後に液滴残存部分が膜欠点となって膜性能が低下することを防ぐことができる。液切りの方法としては、例えば、特開平２−７８４２８号公報に記載されているように、多官能アミン水溶液接触後の多孔性支持膜を垂直方向に把持して過剰の水溶液を自然流下させる方法や、エアーノズルから窒素などの風を吹き付け、強制的に液切りする方法などを用いることができる。また、液切り後、膜面を乾燥させ、水溶液の水の一部を除去することもできる。 After the polyfunctional amine aqueous solution is brought into contact with the porous support membrane, the solution is sufficiently drained so that no droplets remain on the membrane. By sufficiently draining the liquid, it is possible to prevent the remaining portion of the liquid droplet from becoming a film defect after the film is formed and deteriorating the film performance. As a method of draining, for example, as described in JP-A-2-78428, a method of allowing an excess aqueous solution to naturally flow down by vertically gripping a porous support membrane after contacting a polyfunctional amine aqueous solution. Alternatively, a method of forcibly draining by blowing air such as nitrogen from an air nozzle can be used. In addition, after draining, the membrane surface can be dried to remove part of the water in the aqueous solution.
次いで、多官能アミン水溶液接触後の支持膜に、多官能酸ハロゲン化物を含む有機溶媒溶液を接触させ、界面重縮合により架橋ポリアミド分離機能層の骨格を形成させる。 Next, an organic solvent solution containing a polyfunctional acid halide is brought into contact with the support film after contact with the polyfunctional amine aqueous solution, and a skeleton of a crosslinked polyamide separation functional layer is formed by interfacial polycondensation.
有機溶媒溶液中の多官能酸ハロゲン化物の濃度は、０．０１〜１０重量％の範囲内であると好ましく、０．０２〜２重量％の範囲内であるとさらに好ましい。この範囲であると、十分な反応速度が得られ、また副反応の発生を抑制することができる。さらに、この有機溶媒溶液にＮ，Ｎ−ジメチルホルムアミドのようなアシル化触媒を含有させると、界面重縮合が促進され、さらに好ましい。 The concentration of the polyfunctional acid halide in the organic solvent solution is preferably in the range of 0.01 to 10% by weight, and more preferably in the range of 0.02 to 2% by weight. Within this range, a sufficient reaction rate can be obtained, and the occurrence of side reactions can be suppressed. Further, it is more preferable that an acylation catalyst such as N, N-dimethylformamide is contained in the organic solvent solution because interfacial polycondensation is promoted.
有機溶媒は、水と非混和性であり、かつ酸ハロゲン化物を溶解し微多孔性支持膜を破壊しないことが望ましく、多官能アミンおよび多官能酸ハロゲン化物に対して不活性であるものであればよい。好ましい例としては、例えば、ｎ−ヘキサン、ｎ−オクタン、ｎ−デカンなどの炭化水素化合物が挙げられる。 The organic solvent should be immiscible with water and should not dissolve the acid halide and destroy the microporous support membrane, and should be inert to polyfunctional amines and polyfunctional acid halides. That's fine. Preferable examples include hydrocarbon compounds such as n-hexane, n-octane, and n-decane.
多官能酸ハロゲン化物の有機溶媒溶液の多官能アミン水溶液相への接触の方法は、多官能アミン水溶液の微多孔性支持膜への被覆方法と同様に行えばよい。 The method for contacting the organic solvent solution of the polyfunctional acid halide with the polyfunctional amine aqueous solution phase may be performed in the same manner as the method for coating the polyfunctional amine aqueous solution on the microporous support membrane.
上述したように、酸ハロゲン化物の有機溶媒溶液を接触させて界面重縮合を行い、多孔性支持膜上に架橋ポリアミドを含む分離機能層を形成したあとは、余剰の溶媒を液切りするとよい。液切りの方法は、例えば、膜を垂直方向に把持して過剰の有機溶媒を自然流下して除去する方法を用いることができる。この場合、垂直方向に把持する時間としては、１〜５分間の間にあることが好ましく、１〜３分間であるとより好ましい。短すぎると分離機能層が完全に形成せず、長すぎると有機溶媒が過乾燥となり欠点が発生しやすく、性能低下を起こしやすい。 As described above, after the interface polycondensation is performed by bringing the acid halide organic solvent solution into contact with each other and the separation functional layer containing the crosslinked polyamide is formed on the porous support membrane, the excess solvent may be drained. As a method for draining, for example, a method in which a film is held in a vertical direction and excess organic solvent is allowed to flow down and removed can be used. In this case, the time for gripping in the vertical direction is preferably 1 to 5 minutes, more preferably 1 to 3 minutes. If it is too short, the separation functional layer will not be completely formed, and if it is too long, the organic solvent will be overdried and defects will easily occur and performance will be deteriorated.
上述の方法により得られた複合半透膜は、５０〜１５０℃の範囲内、好ましくは７０〜１３０℃の範囲内で１〜１０分間、より好ましくは２〜８分間熱水処理する工程などを付加することで、複合半透膜の脱塩性能や透水性能をより一層向上させることができる。 The composite semipermeable membrane obtained by the above-described method includes a step of hydrothermal treatment in a range of 50 to 150 ° C., preferably in a range of 70 to 130 ° C. for 1 to 10 minutes, more preferably 2 to 8 minutes. By adding, the desalination performance and water permeation performance of the composite semipermeable membrane can be further improved.
このように形成される本発明の複合半透膜は、プラスチックネットなどの原水流路材と、トリコットなどの透過水流路材と、必要に応じて耐圧性を高めるためのフィルムと共に、多数の孔を穿設した筒状の集水管の周りに巻回され、スパイラル型の複合半透膜エレメントとして好適に用いられる。さらに、このエレメントを直列または並列に接続して圧力容器に収納した複合半透膜モジュールとすることもできる。 The composite semipermeable membrane of the present invention formed in this way has a large number of pores together with a raw water channel material such as a plastic net, a permeate channel material such as tricot, and a film for increasing pressure resistance if necessary. Is wound around a cylindrical water collecting pipe and is suitably used as a spiral composite semipermeable membrane element. Furthermore, a composite semipermeable membrane module in which these elements are connected in series or in parallel and accommodated in a pressure vessel can be obtained.
また、上記の複合半透膜やそのエレメント、モジュールは、それらに原水を供給するポンプや、その原水を前処理する装置などと組み合わせて、流体分離装置を構成することができる。この分離装置を用いることにより、原水から飲料水などの透過水と、膜を透過しなかった濃縮水を分離して、目的にあった水を得ることができる。 In addition, the above-described composite semipermeable membrane, its elements, and modules can be combined with a pump that supplies raw water to them, a device that pretreats the raw water, and the like to form a fluid separation device. By using this separation device, permeated water such as drinking water and concentrated water that has not permeated through the membrane can be separated from the raw water, and water suitable for the purpose can be obtained.
流体分離装置の操作圧力は高い方が脱塩率は向上するが、運転に必要なエネルギーも上昇すること、また、複合半透膜の耐久性を考慮すると、複合半透膜に被処理水を透過する際の操作圧力は、海水脱塩条件では１ＭＰａ以上、１０ＭＰａ以下が好ましい。またかん水脱塩条件では０．３ＭＰａ以上、５ＭＰａ以下が好ましい。供給水温度は、高くなると脱塩率が低下するが、低くなるにしたがい透水性能も減少するので、５℃以上、４５℃以下が好ましい。また、供給水ｐＨは、高くなると、海水などの高塩濃度の供給水の場合、マグネシウムなどのスケールが発生する恐れがあり、低くなると膜の劣化が懸念されるため、中性領域での運転が好ましい。 The higher the operating pressure of the fluid separator, the higher the desalination rate, but the energy required for operation also increases, and considering the durability of the composite semipermeable membrane, water to be treated is added to the composite semipermeable membrane. The operating pressure for permeation is preferably 1 MPa or more and 10 MPa or less under seawater desalting conditions. Moreover, 0.3MPa or more and 5MPa or less are preferable on the brine demineralization conditions. As the feed water temperature increases, the desalination rate decreases. However, as the water supply temperature decreases, the water permeation performance also decreases. In addition, when the supply water pH is high, scales such as magnesium may be generated in the case of high salt concentration supply water such as seawater, and when it is low, there is a concern about membrane deterioration. Is preferred.
実施例および比較例における測定は次のとおり行った。
（脱塩率：海水脱塩用膜）
複合半透膜に、温度２５℃、ｐＨ６．５に調整したＴＤＳ濃度約３．５％の海水を操作圧力５．５ＭＰａで供給するときの透過水塩濃度を測定することにより、次の式から求めた。
脱塩率＝１００×｛１−（透過水中の塩濃度／供給水中の塩濃度）｝
Measurements in Examples and Comparative Examples were performed as follows.
(Desalination rate: membrane for seawater desalination)
By measuring the permeate salt concentration when supplying seawater with a TDS concentration of about 3.5% adjusted to a temperature of 25 ° C. and pH 6.5 to the composite semipermeable membrane at an operating pressure of 5.5 MPa, the following equation is obtained. Asked.
Desalination rate = 100 × {1− (salt concentration in permeated water / salt concentration in feed water)}
（脱塩率：かん水脱塩用膜）
複合半透膜に、温度２５℃、ｐＨ６．５に調整した１５００ｐｐｍの塩化ナトリウム水溶液を操作圧力１．５ＭＰａで供給するときの透過水塩濃度を測定することにより、次の式から求めた。
脱塩率＝１００×｛１−（透過水中の塩濃度／供給水中の塩濃度）｝
(Desalination rate: brine for desalination)
The composite semipermeable membrane was determined from the following equation by measuring the permeate salt concentration when a 1500 ppm sodium chloride aqueous solution adjusted to a temperature of 25 ° C. and pH 6.5 was supplied at an operating pressure of 1.5 MPa.
Desalination rate = 100 × {1− (salt concentration in permeated water / salt concentration in feed water)}
（膜透過流束：海水脱塩用膜）
供給水として前記した海水を使用し、膜面１平方メートル当たり、１日の透水量（立方メートル）から膜透過流束（ｍ３／ｍ２・日）を求めた。
(Membrane permeation flux: membrane for seawater desalination)
The seawater described above was used as the feed water, and the membrane permeation flux (m 3 / m 2 · day) was determined from the amount of water per day (cubic meter) per square meter of membrane surface.
（膜透過流束：かん水脱塩用膜）
供給水として前記した１５００ｐｐｍの塩化ナトリウム水溶液を使用し、膜面１平方メートル当たり、１日の透水量（立方メートル）から膜透過流束（ｍ３／ｍ２・日）を求めた。
(Membrane permeation flux: membrane for brine desalination)
The above-mentioned 1500 ppm sodium chloride aqueous solution was used as the feed water, and the membrane permeation flux (m 3 / m 2 · day) was determined from the amount of water per day (cubic meter) per square meter of membrane surface.
（溶質透過係数）
「膜処理技術大系」、上巻、ｐ１７１、中垣 正幸 監修，フジテクノシステム（１９９１）記載の以下の計算式から求めた。
溶質透過係数（ｍ／ｓ）＝｛（１００−脱塩率）／脱塩率｝×膜透過流束×１１５．７×１０−７
(Solute permeability coefficient)
It calculated | required from the following calculation formulas of "Membrane processing technology large series", the first volume, p171, the supervision of Masayuki Nakagaki, and the Fuji techno system (1991).
Solute permeability coefficient (m / s) = {(100−desalting rate) / desalting rate} × membrane permeation flux × 115.7 × 10 −7
（実施例１）
ポリエステル不織布（通気度０．５〜１ｃｃ／ｃｍ２・ｓｅｃ）上にポリスルホンの１５．３重量％ジメチルホルムアミド（ＤＭＦ）溶液を２００μｍの厚みで室温（２５℃）でキャストし、ただちに純水中に浸漬して５分間放置することによって微多孔性支持膜を作製した。このようにして得られた微多孔性支持膜（厚さ２１０〜２１５μｍ）を、塩化ナトリウム０．５重量％を含有するｍ−フェニレンジアミン（以下ｍＰＤＡという）２．０重量％水溶液中に２分間浸漬した。アミン水溶液のｐＨは６．７であった。次に該支持膜を垂直方向にゆっくりと引き上げ、エアーノズルから窒素を吹き付け支持膜表面から余分な水溶液を取り除いた後、トリメシン酸クロリド（以下ＴＭＣという）０．１６５重量％のｎ−デカン溶液を表面が完全に濡れるように塗布して１分間静置した。次に膜から余分な溶液を除去するために、膜を１分間垂直に把持して液切りした。その後、９０℃の熱水で２分間洗浄した後、ｐＨ７、塩素濃度２００ｍｇ／ｌに調整した次亜塩素酸ナトリウム水溶液に２分間浸漬し、亜硫酸水素ナトリウム濃度が１，０００ｍｇ／ｌの水溶液中に浸漬することで、余分な次亜塩素酸ナトリウムを還元除去した。さらに、この膜を９５℃の熱水で２分間再洗浄した。
Example 1
A 15.3% by weight dimethylformamide (DMF) solution of polysulfone was cast on a polyester non-woven fabric (air permeability 0.5 to 1 cc / cm 2 · sec) at a room temperature (25 ° C.) with a thickness of 200 μm and immediately put into pure water. A microporous support membrane was prepared by immersing and allowing to stand for 5 minutes. The microporous support membrane (thickness 210 to 215 μm) thus obtained was placed in a 2.0 wt% aqueous solution of m-phenylenediamine (hereinafter referred to as mPDA) containing 0.5 wt% of sodium chloride for 2 minutes. Soaked. The pH of the aqueous amine solution was 6.7. Next, the support film was slowly pulled up in the vertical direction, nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the support film, and then a 0.165% by weight n-decane solution of trimesic acid chloride (hereinafter referred to as TMC) was added. It was applied so that the surface was completely wet and allowed to stand for 1 minute. Next, in order to remove excess solution from the membrane, the membrane was held vertically for 1 minute to drain the solution. Then, after washing with hot water at 90 ° C. for 2 minutes, it was immersed in an aqueous solution of sodium hypochlorite adjusted to pH 7 and a chlorine concentration of 200 mg / l for 2 minutes, and in an aqueous solution having a sodium bisulfite concentration of 1,000 mg / l. By dipping, excess sodium hypochlorite was reduced and removed. Furthermore, this membrane was rewashed with hot water at 95 ° C. for 2 minutes.
得られた複合半透膜を海水脱塩用膜として評価したところ、透過流束が０．９９ｍ３／ｍ２・日、脱塩率は９９．８７％、溶質透過係数は１．４×１０−８ｍ／ｓであり、アミン濃度が２．０重量％と低濃度の多官能アミン水溶液を使用したにもかかわらず海水脱塩用途として使用できる複合半透膜が得られた。 When the obtained composite semipermeable membrane was evaluated as a seawater desalination membrane, the permeation flux was 0.99 m 3 / m 2 · day, the desalination rate was 99.87%, and the solute permeability coefficient was 1.4 × 10. A composite semipermeable membrane that can be used for seawater desalination was obtained despite the use of a polyfunctional amine aqueous solution having a low amine concentration of 2.0% by weight at −8 m / s.
（実施例２）
塩化ナトリウムを５重量％添加した多官能アミン水溶液を使用した以外は、実施例１と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは６．５であった。海水脱塩用膜として膜性能評価を行ったところ、透過流束が０．６１ｍ３／ｍ２・日、脱塩率は９９．８２％、溶質透過係数は１．３×１０−８ｍ／ｓであり、海水脱塩用途として使用できる複合半透膜が得られた。
(Example 2)
A composite semipermeable membrane was produced in the same manner as in Example 1 except that a polyfunctional amine aqueous solution added with 5% by weight of sodium chloride was used. The pH of the aqueous amine solution was 6.5. When the membrane performance was evaluated as a seawater desalination membrane, the permeation flux was 0.61 m 3 / m 2 · day, the desalination rate was 99.82%, and the solute permeability coefficient was 1.3 × 10 −8 m / day. It was s and the composite semipermeable membrane which can be used for a seawater desalination use was obtained.
（比較例１）
アミン水溶液に塩化ナトリウムを添加せずに実施例１と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは６．６であった。得られた膜を海水脱塩用膜として膜性能評価を行ったところ、透過流束が１．０２ｍ３／ｍ２・日、脱塩率は９９．８２％、溶質透過係数は２．１×１０−８ｍ／ｓであり、溶質透過係数が海水脱塩用途としては性能未達であった。
(Comparative Example 1)
A composite semipermeable membrane was produced in the same manner as in Example 1 without adding sodium chloride to the aqueous amine solution. The pH of the aqueous amine solution was 6.6. When the membrane performance was evaluated using the obtained membrane as a membrane for seawater desalination, the permeation flux was 1.02 m 3 / m 2 · day, the desalination rate was 99.82%, and the solute permeability coefficient was 2.1 ×. 10 −8 m / s, and the solute permeability coefficient was unsatisfactory for seawater desalination.
（比較例２）
塩化ナトリウムの代わりにリン酸三ナトリウムを０．５重量％添加して、実施例１と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは１２．０であった。海水脱塩用膜として膜性能評価を行ったところ、透過流束が０．９７ｍ３／ｍ２・日、脱塩率は９９．８５％、溶質透過係数は１．７×１０−８ｍ／ｓであり、溶質透過係数が海水脱塩用途としては性能未達であった。
(Comparative Example 2)
A composite semipermeable membrane was produced in the same manner as in Example 1 except that 0.5% by weight of trisodium phosphate was added instead of sodium chloride. The pH of the aqueous amine solution was 12.0. When the membrane performance was evaluated as a membrane for seawater desalination, the permeation flux was 0.97 m 3 / m 2 · day, the desalination rate was 99.85%, and the solute permeability coefficient was 1.7 × 10 −8 m / day. It was s, and the solute permeability coefficient was not sufficient for seawater desalination.
（比較例３）
塩化ナトリウムの代わりにリン酸三ナトリウムを５重量％添加して、実施例１と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは１２．２であった。海水脱塩用膜として膜性能評価を行ったところ、透過流束が０．４９ｍ３／ｍ２・日、脱塩率は９９．８５％、溶質透過係数は０．９×１０−８ｍ／ｓであり、透過流束が海水脱塩用途としては性能未達であった。
(Comparative Example 3)
A composite semipermeable membrane was produced in the same manner as in Example 1 except that 5% by weight of trisodium phosphate was added instead of sodium chloride. The pH of the aqueous amine solution was 12.2. When membrane performance was evaluated as a seawater desalination membrane, the permeation flux was 0.49 m 3 / m 2 · day, the desalination rate was 99.85%, and the solute permeability coefficient was 0.9 × 10 −8 m / day. s, and the permeation flux was not sufficient for seawater desalination.
（実施例３）
ポリエステル不織布（通気度０．５〜１ｃｃ／ｃｍ２・ｓｅｃ）上にポリスルホンの１５．７重量％ジメチルホルムアミド溶液を２００μｍの厚みで室温（２５℃）でキャストし、ただちに純水中に浸漬して５分間放置することによって微多孔性支持膜を作製した。このようにして得られた微多孔性支持膜（厚さ２１０〜２１５μｍ）を、塩化ナトリウム０．５重量％を含有するｍ−フェニレンジアミン１重量％水溶液中に２分間浸漬した。アミン水溶液のｐＨは６．７であった。次に該支持膜を垂直方向にゆっくりと引き上げ、エアーノズルから窒素を吹き付け支持膜表面から余分な水溶液を取り除いた後、トリメシン酸クロリド０．１重量％のｎ−デカン溶液を表面が完全に濡れるように塗布して１分間静置した。次に膜から余分な溶液を除去するために、膜を１分間垂直に把持して液切りした。その後、９０℃の熱水で２分間洗浄した後、ｐＨ７、塩素濃度５００ｍｇ／ｌに調整した次亜塩素酸ナトリウム水溶液に２分間浸漬し、亜硫酸水素ナトリウム濃度が１，０００ｍｇ／ｌの水溶液中に浸漬することで、余分な次亜塩素酸ナトリウムを還元除去した。
(Example 3)
A 15.7 wt% dimethylformamide solution of polysulfone was cast at a room temperature (25 ° C.) with a thickness of 200 μm on a polyester nonwoven fabric (air permeability 0.5 to 1 cc / cm 2 · sec) and immediately immersed in pure water. A microporous support membrane was prepared by leaving it for 5 minutes. The microporous support membrane (thickness 210 to 215 μm) thus obtained was immersed for 2 minutes in a 1% by weight aqueous solution of m-phenylenediamine containing 0.5% by weight of sodium chloride. The pH of the aqueous amine solution was 6.7. Next, the support film is slowly pulled up in the vertical direction, nitrogen is blown from an air nozzle to remove excess aqueous solution from the surface of the support film, and then the surface is completely wetted with an n-decane solution containing 0.1% by weight of trimesic acid chloride. And applied for 1 minute. Next, in order to remove excess solution from the membrane, the membrane was held vertically for 1 minute to drain the solution. Then, after washing with hot water at 90 ° C. for 2 minutes, it was immersed in an aqueous solution of sodium hypochlorite adjusted to pH 7 and a chlorine concentration of 500 mg / l for 2 minutes, and in an aqueous solution having a sodium bisulfite concentration of 1,000 mg / l. By dipping, excess sodium hypochlorite was reduced and removed.
得られた複合半透膜をかん水脱塩用膜として評価したところ、透過流束が１．２７ｍ３／ｍ２・日、脱塩率は９９．７９％、溶質透過係数は１．９×１０−８ｍ／ｓであり、アミン濃度が０．５重量％と低濃度の多官能アミン水溶液を使用したにもかかわらずかん水脱塩用途として使用できる複合半透膜が得られた。 When the obtained composite semipermeable membrane was evaluated as a brine demineralization membrane, the permeation flux was 1.27 m 3 / m 2 · day, the desalination rate was 99.79%, and the solute permeability coefficient was 1.9 × 10. A composite semipermeable membrane that can be used for brackish water desalination was obtained despite the use of a polyfunctional amine aqueous solution having a low amine concentration of 0.5% by weight at -8 m / s.
（実施例４）
塩化ナトリウムを１重量％添加した多官能アミン水溶液を使用した以外は、実施例３と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは６．５であった。かん水脱塩用膜として膜性能評価を行ったところ、透過流束が１．２２ｍ３／ｍ２・日、脱塩率は９９．７９％、溶質透過係数は１．８×１０−８ｍ／ｓであり、かん水脱塩用途として使用できる複合半透膜が得られた。
Example 4
A composite semipermeable membrane was produced in the same manner as in Example 3 except that a polyfunctional amine aqueous solution added with 1% by weight of sodium chloride was used. The pH of the aqueous amine solution was 6.5. When the membrane performance was evaluated as a brine demineralization membrane, the permeation flux was 1.22 m 3 / m 2 · day, the desalination rate was 99.79%, and the solute permeability coefficient was 1.8 × 10 −8 m / day. It was s and the composite semipermeable membrane which can be used for a brine desalination use was obtained.
（比較例４）
アミン水溶液に塩化ナトリウムを添加せずに実施例３と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは６．５であった。得られた膜をかん水脱塩用膜として膜性能評価を行ったところ、透過流束が１．４２ｍ３／ｍ２・日、脱塩率は９９．７３％、溶質透過係数は２．７×１０−８ｍ／ｓであり、溶質透過係数がかん水脱塩用途としては性能未達であった。
(Comparative Example 4)
A composite semipermeable membrane was produced in the same manner as in Example 3 without adding sodium chloride to the aqueous amine solution. The pH of the aqueous amine solution was 6.5. When the membrane performance was evaluated using the obtained membrane as a brine-desalting membrane, the permeation flux was 1.42 m 3 / m 2 · day, the desalination rate was 99.73%, and the solute permeability coefficient was 2.7 ×. 10 −8 m / s, and the solute permeability coefficient was unsatisfactory for use in brine desalination.
（比較例５）
塩化ナトリウムの代わりにリン酸三ナトリウムを０．５重量％を添加して、実施例３と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは１２．０であった。得られた膜をかん水脱塩用膜として膜性能評価を行ったところ、透過流束が１．２８ｍ３／ｍ２・日、脱塩率は９９．７５％、溶質透過係数は２．４×１０−８ｍ／ｓであり、溶質透過係数がかん水脱塩用途としては性能未達であった。
(Comparative Example 5)
A composite semipermeable membrane was produced in the same manner as in Example 3 except that 0.5% by weight of trisodium phosphate was added instead of sodium chloride. The pH of the aqueous amine solution was 12.0. When the membrane performance was evaluated using the obtained membrane as a brine-desalting membrane, the permeation flux was 1.28 m 3 / m 2 · day, the desalination rate was 99.75%, and the solute permeability coefficient was 2.4 ×. 10 −8 m / s, and the solute permeability coefficient was unsatisfactory for use in brine desalination.
（比較例６）
塩化ナトリウムの代わりにリン酸三ナトリウムを５重量％を添加して、実施例３と同様の方法で複合半透膜を製造した。アミン水溶液のｐＨは１２．２であった。かん水脱塩用膜として膜性能評価を行ったところ、透過流束が１．０７ｍ３／ｍ２・日、脱塩率は９９．５７％、溶質透過係数は３．６×１０−８ｍ／ｓであり、溶質透過係数がかん水脱塩用途としては性能未達であった。
(Comparative Example 6)
A composite semipermeable membrane was produced in the same manner as in Example 3 except that 5% by weight of trisodium phosphate was added instead of sodium chloride. The pH of the aqueous amine solution was 12.2. When the membrane performance was evaluated as a brine demineralization membrane, the permeation flux was 1.07 m 3 / m 2 · day, the desalination rate was 99.57%, and the solute permeability coefficient was 3.6 × 10 −8 m / day. s, and the solute permeability coefficient was unsatisfactory for use in brine desalination.
本発明法によると、使用する多官能アミン水溶液のアミン濃度を低減させた場合でも、実用性のある高脱塩率、高透過流束を達成できる複合半透膜が得られるので、本発明による複合半透膜は、海水またはかん水の脱塩、染色や電着塗料廃水の除去・分離回収による工業用水のクローズドシステム構築、食品工業での有効成分の濃縮等に好適に用いることができる。 According to the method of the present invention, even when the amine concentration of the polyfunctional amine aqueous solution to be used is reduced, a composite semipermeable membrane capable of achieving a practical high desalination rate and high permeation flux can be obtained. The composite semipermeable membrane can be suitably used for desalination of seawater or brine, construction of a closed system for industrial water by dyeing or removal / separation recovery of electrodeposition paint wastewater, concentration of active ingredients in the food industry, and the like.
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