JP2014144448A - Method for producing separation membrane - Google Patents
Method for producing separation membraneInfo
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本発明は、固液分離、液中の固形分分画、気固分離等に使用可能な分離膜の製造方法に関するものである。 The present invention relates to a method for producing a separation membrane that can be used for solid-liquid separation, solid fractionation in liquid, gas-solid separation, and the like.
従来、有機材料や無機材料からなる様々な分離膜が知られており、実用に供されている。分離膜においては、所望する分離性能を発現し、高い透過性能を有することが求められ、これまで様々な分離膜が提案されている。例えば特許文献１には、分離膜に適用可能な微粒子膜の製造方法として、無機粒子を高分子材料中に分散させた分散混合物を基材に塗布した後、高分子材料を揮発または分解除去して、微粒子層を形成する方法が開示されている。 Conventionally, various separation membranes made of organic materials or inorganic materials are known and put into practical use. Separation membranes are required to exhibit desired separation performance and have high permeation performance, and various separation membranes have been proposed so far. For example, in Patent Document 1, as a method for producing a fine particle membrane applicable to a separation membrane, a dispersion mixture in which inorganic particles are dispersed in a polymer material is applied to a substrate, and then the polymer material is volatilized or decomposed and removed. Thus, a method for forming a fine particle layer is disclosed.
上記のように従来様々な分離膜が提案されているが、分離膜においては、分離性能を決定する分離層が、できるだけ薄く、かつできるだけ均一な孔径を有するように形成されることが望まれ、そのような分離層を形成できれば、分離性能に優れ、高い透過性能を有する分離膜が得られることが期待される。そのような点において、分離層の構造や機能を容易に設計あるいは制御できる方法があれば、高機能の分離膜の開発に繋がる可能性が広がり、有望である。本発明は前記事情に鑑みてなされたものであり、その目的は、分離層の構造や機能を容易に制御できる新規な分離膜の製造方法を提供することにある。 Various separation membranes have been conventionally proposed as described above. In the separation membrane, it is desired that the separation layer that determines the separation performance is formed to be as thin as possible and to have a uniform pore size as much as possible. If such a separation layer can be formed, it is expected that a separation membrane having excellent separation performance and high permeation performance can be obtained. In this respect, if there is a method that can easily design or control the structure and function of the separation layer, the possibility of leading to the development of a highly functional separation membrane is widened and promising. This invention is made | formed in view of the said situation, The objective is to provide the manufacturing method of the novel separation membrane which can control the structure and function of a separation layer easily.
前記課題を解決することができた本発明の分離膜の製造方法とは、支持基材を、正荷電無機粒子を含有する溶液と負荷電無機粒子を含有する溶液に交互に浸漬することにより、支持基材上に正荷電無機粒子と負荷電無機粒子を積層させる工程を有するところに特徴を有する。本発明の製造方法によれば、支持基材上に積層させる正荷電無機粒子と負荷電無機粒子の粒子径や積層数を調整することにより、得られる分離膜の分離性能や透過性能を制御することができる。 The method for producing a separation membrane of the present invention that was able to solve the above-mentioned problem is that the support substrate is alternately immersed in a solution containing positively charged inorganic particles and a solution containing negatively charged inorganic particles, It is characterized in that it has a step of laminating positively charged inorganic particles and negatively charged inorganic particles on a supporting substrate. According to the production method of the present invention, the separation performance and permeation performance of the obtained separation membrane are controlled by adjusting the particle diameter and the number of layers of the positively charged inorganic particles and the negatively charged inorganic particles to be laminated on the support substrate. be able to.
無機粒子としては、金属粒子または金属酸化物粒子を用いることが好ましい。無機粒子として金属粒子を用いる場合は、正荷電無機粒子（正荷電金属粒子）が、カチオン性安定化剤の存在下で金属イオンを還元させることにより得られるものであることが好ましく、負荷電無機粒子（負荷電金属粒子）が、アニオン性安定化剤の存在下で金属イオンを還元させることにより得られるものであることが好ましい。このように正荷電無機粒子と負荷電無機粒子を調製することにより、粒子径の制御された正荷電無機粒子と負荷電無機粒子を簡便に得ることができる。 As the inorganic particles, it is preferable to use metal particles or metal oxide particles. When metal particles are used as the inorganic particles, the positively charged inorganic particles (positively charged metal particles) are preferably obtained by reducing metal ions in the presence of a cationic stabilizer. The particles (negatively charged metal particles) are preferably those obtained by reducing metal ions in the presence of an anionic stabilizer. Thus, by preparing positively charged inorganic particles and negatively charged inorganic particles, positively charged inorganic particles and negatively charged inorganic particles with controlled particle diameters can be easily obtained.
本発明は、本発明の製造方法により得られる分離膜を提供する。本発明によれば、分離性能や透過性能が制御された分離膜を提供することができる。 The present invention provides a separation membrane obtained by the production method of the present invention. According to the present invention, it is possible to provide a separation membrane with controlled separation performance and permeation performance.
本発明の分離膜の製造方法によれば、支持基材上に積層させる正荷電無機粒子と負荷電無機粒子の粒子径や積層数を調整することにより、得られる分離膜の分離性能や透過性能を容易に制御することができる。 According to the method for producing a separation membrane of the present invention, the separation performance and permeation performance of the resulting separation membrane can be adjusted by adjusting the particle diameter and the number of layers of positively charged inorganic particles and negatively charged inorganic particles to be laminated on a support substrate Can be easily controlled.
本発明は、固液分離、液中の固形分分画、気固分離等に好適に用いられる分離膜の製造方法に関するものであり、膜の処理性能を高度に制御することが可能な分離膜の製造方法に関するものである。 The present invention relates to a method for producing a separation membrane suitably used for solid-liquid separation, solid fractionation in liquid, gas-solid separation, and the like, and a separation membrane capable of highly controlling membrane treatment performance. It is related with the manufacturing method.
本発明の分離膜の製造方法は、支持基材を、正荷電無機粒子を含有する溶液と負荷電無機粒子を含有する溶液に交互に浸漬することにより、支持基材上に正荷電無機粒子と負荷電無機粒子を積層させる工程を有しており、支持基材上に積層させる正荷電無機粒子と負荷電無機粒子の粒子径や積層数を調整することにより、得られる分離膜の分離性能（例えば、（公称）孔径や分画分子量等）や透過性能（膜透過流束）を制御することができる。なお本発明において、「溶液」には「分散液」の意味も含まれるものとする。本発明の製造方法により得られる分離膜は、支持基材がいわゆる支持層として機能し、支持基材上に積層した正荷電無機粒子と負荷電無機粒子がいわゆる分離層として機能する。 In the method for producing a separation membrane of the present invention, the support substrate is alternately immersed in a solution containing positively charged inorganic particles and a solution containing negatively charged inorganic particles, whereby positively charged inorganic particles and It has a step of laminating negatively charged inorganic particles, and the separation performance of the separation membrane obtained by adjusting the particle diameter and the number of laminated layers of positively charged inorganic particles and negatively charged inorganic particles to be laminated on the support substrate ( For example, (nominal pore diameter, molecular weight cut off, etc.) and permeation performance (membrane permeation flux) can be controlled. In the present invention, the term “solution” includes the meaning of “dispersion”. In the separation membrane obtained by the production method of the present invention, the support substrate functions as a so-called support layer, and the positively charged inorganic particles and the negatively charged inorganic particles stacked on the support substrate function as a so-called separation layer.
従来、相異なる電荷を有する粒子を交互に積層させて薄膜を作成する方法は知られていた。例えば特開２０１１−１８３５１９号公報には、無機粒子を内包した相異なる電荷を有するタンパク分子を交互に積層させて薄膜を製造する方法が記載され、特開２００９−１１３４８４号公報には、無機酸化物粒子と相異なる電荷を有する電解質ポリマーを交互に積層させて薄膜を製造する方法が開示されている。しかしこれらの特許文献には、得られた薄膜を分離膜に適用することについては記載されていない。これに対して本発明では、相異なる電荷を有する無機粒子を支持基材上に交互に積層させることにより、膜処理性能が高度に制御された分離膜を得ることが可能であることを見出した。 Conventionally, a method for forming a thin film by alternately laminating particles having different charges has been known. For example, Japanese Patent Application Laid-Open No. 2011-183519 describes a method of manufacturing a thin film by alternately laminating protein molecules having different charges encapsulating inorganic particles, and Japanese Patent Application Laid-Open No. 2009-113484 discloses inorganic oxidation. A method of manufacturing a thin film by alternately laminating electrolyte polymers having different charges from physical particles is disclosed. However, these patent documents do not describe application of the obtained thin film to a separation membrane. On the other hand, in the present invention, it was found that a separation membrane with highly controlled membrane treatment performance can be obtained by alternately laminating inorganic particles having different charges on a support substrate. .
支持基材は、固形分が通過できる空間を有するものであれば特に限定されず、一般的な分離膜で支持層として用いられる多孔質材料を使用することができる。支持基材は、無機材料から構成されていてもよく、有機材料から構成されていてもよい。なお本発明に係る分離膜は、分離層が正荷電無機粒子と負荷電無機粒子から形成されており、分離層を構成する無機粒子に由来して耐久性（例えば、耐薬品性等）の向上が期待されることから、分離膜全体の耐久性を向上させるために、支持基材も無機材料から構成されていることが好ましい。支持基材としては、例えば、分離膜に多く用いられる無機材料としてセラミックを用いることができ、セラミックとしては例えば、アルミナ、シリカ、アルミナ−シリカ、チタニア、ジルコニア等の酸化物（複合酸化物を含む）を用いることができる。 The support base material is not particularly limited as long as it has a space through which a solid content can pass, and a porous material used as a support layer in a general separation membrane can be used. The support base material may be comprised from the inorganic material and may be comprised from the organic material. In the separation membrane according to the present invention, the separation layer is formed of positively charged inorganic particles and negatively charged inorganic particles, and the durability (eg, chemical resistance) is improved due to the inorganic particles constituting the separation layer. Therefore, in order to improve the durability of the entire separation membrane, it is preferable that the support substrate is also made of an inorganic material. As the support substrate, for example, ceramic can be used as an inorganic material often used for separation membranes. Examples of the ceramic include oxides (including composite oxides) such as alumina, silica, alumina-silica, titania, zirconia. ) Can be used.
支持基材上に正荷電無機粒子と負荷電無機粒子が好適に堆積できるように、支持基材の孔径（支持基材の分離性能を表す（公称）孔径）は、正荷電無機粒子の平均粒子径と負荷電無機粒子の平均粒子径よりも小さいことが好ましい。 In order that positively charged inorganic particles and negatively charged inorganic particles can be suitably deposited on the support substrate, the pore size of the support substrate (the (nominal) pore size representing the separation performance of the support substrate) is the average particle of the positively charged inorganic particles. The diameter and the average particle diameter of the negatively charged inorganic particles are preferably smaller.
正荷電無機粒子は、正電荷を有する無機粒子であれば特に限定されない。負荷電無機粒子も、負電荷を有する無機粒子であれば特に限定されない。本発明の製造方法によれば、無機粒子の種類に関わらず、支持基材を正荷電無機粒子を含有する溶液と負荷電無機粒子を含有する溶液に交互に浸漬することにより、支持基材上に正荷電無機粒子と負荷電無機粒子を積層させることができる。 The positively charged inorganic particles are not particularly limited as long as they are inorganic particles having a positive charge. The negatively charged inorganic particles are not particularly limited as long as they are inorganic particles having a negative charge. According to the production method of the present invention, regardless of the type of inorganic particles, the support substrate is alternately immersed in a solution containing positively charged inorganic particles and a solution containing negatively charged inorganic particles, thereby In addition, positively charged inorganic particles and negatively charged inorganic particles can be laminated.
無機粒子に正電荷または負電荷を与える方法は特に限定されない。例えば、無機粒子をアニオン性基またはカチオン性基を有する化合物と反応させて無機粒子に電荷を持たせてもよいし、無機粒子を製造する際にアニオン性基またはカチオン性基を有する化合物の共存下で反応させて、正電荷または負電荷を有する無機粒子を形成してもよい。また、無機粒子を製造する際にアニオン性基またはカチオン性基を有する化合物と反応しうる化合物の共存下で反応させて無機粒子を形成した後、得られた無機粒子とアニオン性基またはカチオン性基を有する化合物と反応させて、正電荷または負電荷を有する無機粒子を形成してもよい。アニオン性基またはカチオン性基を有する化合物は、例えば、共有結合により無機粒子と結び付いてもよく、配位結合により無機粒子と結び付いてもよく、また、さらに弱い力により相互に結び付いてもよい。 There is no particular limitation on the method for imparting positive charges or negative charges to the inorganic particles. For example, inorganic particles may be reacted with a compound having an anionic group or a cationic group to make the inorganic particles have a charge, or a compound having an anionic group or a cationic group may coexist when producing inorganic particles. You may make it react under and form the inorganic particle which has a positive charge or a negative charge. In addition, when inorganic particles are produced, after reacting in the presence of a compound capable of reacting with a compound having an anionic group or a cationic group to form inorganic particles, the resulting inorganic particles and an anionic group or cationic Reaction with a compound having a group may form inorganic particles having a positive charge or a negative charge. The compound having an anionic group or a cationic group may be bound to the inorganic particle by a covalent bond, may be bound to the inorganic particle by a coordinate bond, or may be bound to each other by a weaker force.
正荷電無機粒子と負荷電無機粒子の粒子径は特に限定されない。本発明の製造方法においては、使用する正荷電無機粒子と負荷電無機粒子の粒子径を適宜調整することにより、正荷電無機粒子と負荷電無機粒子から形成される分離層の孔径（分離層の分離性能を表す（公称）孔径）を変えることができる。なお正荷電無機粒子と負荷電無機粒子としては、入手容易性や製造容易性の点から、ナノオーダーからマイクロオーダーの平均粒子径のものを用いることが好ましく、例えば、１ｎｍ〜１００μｍの平均粒子径のものを用いることが好ましい。このような平均粒子径の正荷電無機粒子と負荷電無機粒子を用いた場合、得られる分離膜は、精密ろ過膜（ＭＦ膜）や限外ろ過膜（ＵＦ膜）として機能しうるものとなる。 The particle diameter of positively charged inorganic particles and negatively charged inorganic particles is not particularly limited. In the production method of the present invention, by appropriately adjusting the particle sizes of the positively charged inorganic particles and the negatively charged inorganic particles to be used, the pore size of the separation layer formed from the positively charged inorganic particles and the negatively charged inorganic particles (of the separated layer) (Nominal) pore size) representing separation performance can be varied. In addition, as positively charged inorganic particles and negatively charged inorganic particles, it is preferable to use particles having an average particle size of nano-order to micro-order from the viewpoint of easy availability and ease of manufacture, for example, an average particle size of 1 nm to 100 μm. It is preferable to use those. When positively charged inorganic particles and negatively charged inorganic particles having such an average particle diameter are used, the obtained separation membrane can function as a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane). .
無機粒子としては、金属または金属酸化物を用いることが好ましい。無機粒子として金属または金属酸化物を用いれば、正荷電無機粒子と負荷電無機粒子を簡便に得ることができる。また、比較的粒径の揃った小粒子径の無機粒子を容易に得ることができる。例えば、ナノ無機粒子（平均粒子径が１ｎｍ〜１０００ｎｍの無機粒子）を容易に得ることができる。 As the inorganic particles, it is preferable to use a metal or a metal oxide. When a metal or metal oxide is used as the inorganic particles, positively charged inorganic particles and negatively charged inorganic particles can be easily obtained. Moreover, it is possible to easily obtain inorganic particles having a relatively small particle diameter. For example, nano inorganic particles (inorganic particles having an average particle diameter of 1 nm to 1000 nm) can be easily obtained.
無機粒子として金属を用いる場合、正荷電無機粒子は正荷電金属粒子となり、負荷電無機粒子は負荷電金属粒子となる。無機粒子として金属粒子を用いる場合、金属粒子は、カチオン性安定化剤により正電荷が付与され、アニオン性安定化剤により負電荷が付与されることが好ましい。そのような金属粒子を得る方法としては、カチオン性安定化剤またはアニオン性安定化剤の存在下で金属イオンを還元する方法や、金属イオンを還元させた後にカチオン性安定化剤またはアニオン性安定化剤を加える方法等が挙げられる。 When a metal is used as the inorganic particles, the positively charged inorganic particles are positively charged metal particles, and the negatively charged inorganic particles are negatively charged metal particles. When metal particles are used as the inorganic particles, the metal particles are preferably given a positive charge by a cationic stabilizer and given a negative charge by an anionic stabilizer. Such metal particles can be obtained by reducing the metal ion in the presence of a cationic stabilizer or an anionic stabilizer, or after reducing the metal ion, the cationic stabilizer or anionic stabilizer. And a method of adding an agent.
本発明においては、無機粒子として金属粒子を用いる場合、正荷電金属粒子が、カチオン性安定化剤の存在下で金属イオンを還元させることにより得られるものであることが好ましく、負荷電金属粒子が、アニオン性安定化剤の存在下で金属イオンを還元させることにより得られるものであることが好ましい。すなわち本発明の製造方法は、カチオン性安定化剤の存在下で金属イオンを還元させることにより正荷電金属粒子を得る工程を有することが好ましく、またアニオン性安定化剤の存在下で金属イオンを還元させることにより負荷電金属粒子を得る工程を有することが好ましい。このように正荷電金属粒子と負荷電金属粒子を製造することにより、正荷電金属粒子と負荷電金属粒子を簡便に得ることができる。また、比較的粒径の揃った小粒子径の金属粒子を容易に得ることができる。 In the present invention, when metal particles are used as the inorganic particles, the positively charged metal particles are preferably obtained by reducing metal ions in the presence of a cationic stabilizer. It is preferably obtained by reducing a metal ion in the presence of an anionic stabilizer. That is, the production method of the present invention preferably has a step of obtaining positively charged metal particles by reducing metal ions in the presence of a cationic stabilizer, and the metal ions are removed in the presence of an anionic stabilizer. It is preferable to have a step of obtaining negatively charged metal particles by reduction. Thus, by producing positively charged metal particles and negatively charged metal particles, positively charged metal particles and negatively charged metal particles can be easily obtained. Moreover, it is possible to easily obtain metal particles having a relatively small particle diameter.
カチオン性安定化剤としては、カチオン性ポリマーや、カチオン性基と金属反応性基（金属との反応性を有する置換基）を有する化合物等を用いることができる。アニオン性安定化剤としては、アニオン性ポリマーや、アニオン性基と金属反応性基（金属との反応性を有する置換基）を有する化合物等を用いることができる。 As the cationic stabilizer, a cationic polymer, a compound having a cationic group and a metal reactive group (a substituent having reactivity with a metal), or the like can be used. As the anionic stabilizer, an anionic polymer, a compound having an anionic group and a metal reactive group (a substituent having reactivity with a metal), or the like can be used.
カチオン性ポリマーは、カチオン性基を有するポリマーであれば特に限定されない。カチオン性基としては、例えば、アミノ基、アンモニウム塩基、イミノ基等が挙げられる。ポリマーの主鎖の構造も特に限定されない。カチオン性ポリマーとしては、金属粒子を水中で安定に分散させる観点から、親水性であることが好ましく、例えば、ポリエチレンイミン、ポリ（ジアリルジメチルアンモニウムクロリド）、ポリ（アリルアミン塩酸塩）等を使用できる。 The cationic polymer is not particularly limited as long as it is a polymer having a cationic group. Examples of the cationic group include an amino group, an ammonium base, and an imino group. The structure of the main chain of the polymer is not particularly limited. The cationic polymer is preferably hydrophilic from the viewpoint of stably dispersing the metal particles in water. For example, polyethyleneimine, poly (diallyldimethylammonium chloride), poly (allylamine hydrochloride) and the like can be used.
アニオン性ポリマーは、アニオン性基を有するポリマーであれば特に限定されない。アニオン性基としては、例えば、カルボキシル基、スルホン酸基、ホスホン酸基等が挙げられる。アニオン性基はプロトン化していてもよく、塩形成していてもよい。ポリマーの主鎖の構造も特に限定されない。アニオン性ポリマーとしては、金属粒子を水中で安定に分散させる観点から、親水性であることが好ましく、例えば、ポリ（４−スチレンスルホン酸）およびその塩など、ポリマーの主鎖中にスルホン酸基やカルボン酸基を有するポリマー等を使用できる。 The anionic polymer is not particularly limited as long as it is a polymer having an anionic group. Examples of the anionic group include a carboxyl group, a sulfonic acid group, and a phosphonic acid group. The anionic group may be protonated or may form a salt. The structure of the main chain of the polymer is not particularly limited. The anionic polymer is preferably hydrophilic from the viewpoint of stably dispersing the metal particles in water. For example, poly (4-styrenesulfonic acid) and a salt thereof such as a sulfonic acid group in the main chain of the polymer. Or a polymer having a carboxylic acid group can be used.
カチオン性安定化剤またはアニオン性安定化剤として、カチオン性基と金属反応性基（金属との反応性を有する置換基）を有する化合物またはアニオン性基と金属反応性基を有する化合物を用いる場合、カチオン性基とアニオン性基としては上記に説明した置換基が挙げられる。金属反応性基としては、チオール基、アミノ基、カルボン酸基、スルホ基等が挙げられる。 When using a compound having a cationic group and a metal-reactive group (substituent having reactivity with a metal) or a compound having an anionic group and a metal-reactive group as the cationic stabilizer or anionic stabilizer Examples of the cationic group and the anionic group include the substituents described above. Examples of the metal reactive group include a thiol group, an amino group, a carboxylic acid group, and a sulfo group.
金属イオンの種類は特に限定されないが、容易に還元して金属を生成しやすい点から、イオン化傾向の小さい金イオン、白金イオン、銀イオン、パラジウムイオン、銅イオン等を用いることが好ましい。金属イオンは、金属塩（例えば、炭酸塩、硝酸塩、塩化物塩）、金属酸化物等の金属化合物を溶解させることにより、調製すればよい。 Although the kind of metal ion is not particularly limited, it is preferable to use gold ion, platinum ion, silver ion, palladium ion, copper ion or the like having a small ionization tendency from the viewpoint of easy reduction to generate a metal. What is necessary is just to prepare a metal ion by dissolving metal compounds, such as a metal salt (for example, carbonate, nitrate, chloride salt), a metal oxide.
金属イオンを還元する方法は特に限定されず、例えば、還元剤を用いて還元したり、電気化学的に還元してもよい。なお、溶液中で比較的粒径の揃った金属粒子を得ることが容易な点から、金属イオンは還元剤で還元させることが好ましい。還元剤は、金属イオンを還元させることができるものであればよく、一般に使用される還元剤（例えば、水素化アルミニウムリチウム、水素化ホウ素ナトリウム等）を用いればよい。 The method for reducing metal ions is not particularly limited. For example, reduction may be performed using a reducing agent, or electrochemical reduction may be performed. In addition, it is preferable to reduce a metal ion with a reducing agent from the viewpoint that it is easy to obtain metal particles having a relatively uniform particle size in a solution. The reducing agent is not particularly limited as long as it can reduce metal ions, and a commonly used reducing agent (for example, lithium aluminum hydride, sodium borohydride, etc.) may be used.
金属イオンをカチオン性安定化剤またはアニオン性安定化剤の存在下で還元させることにより、金属イオンが金属単体に還元されて、金属粒子が生成する。その際、カチオン性安定化剤またはアニオン性安定化剤が金属粒子に取り込まれて、金属粒子が正電荷または負電荷を有するようになる。 By reducing the metal ion in the presence of a cationic stabilizer or an anionic stabilizer, the metal ion is reduced to a single metal, thereby producing metal particles. At that time, the cationic stabilizer or the anionic stabilizer is incorporated into the metal particles, and the metal particles have a positive charge or a negative charge.
金属イオンは水溶液中で還元反応させればよく、この際の温度は特に限定されない。例えば、室温〜８０℃程度で反応を行い、金属粒子を生成させればよい。反応時間も特に限定されず、還元反応の進行度合や金属粒子の成長度合を見ながら反応時間を適宜調整すればよい。反応は、例えば、１分〜２４時間の範囲で行えばよい。 The metal ion may be reduced in an aqueous solution, and the temperature at this time is not particularly limited. For example, the reaction may be performed at room temperature to about 80 ° C. to generate metal particles. The reaction time is not particularly limited, and the reaction time may be appropriately adjusted while checking the progress of the reduction reaction and the growth of the metal particles. The reaction may be performed, for example, in the range of 1 minute to 24 hours.
金属イオンを還元させて金属粒子を生成させる際、金属粒子の粒径は、金属イオン濃度、還元剤濃度、カチオン性またはアニオン性安定化剤濃度の各比を調整することで制御することができる。例えば、最適な混合比で調製した際には最小の粒径を有する金属粒子を得ることができ、この最適な混合比から少しでもずれるとそれより大きい粒径を有する金属粒子を得ることができる。 When reducing metal ions to form metal particles, the particle size of the metal particles can be controlled by adjusting each ratio of metal ion concentration, reducing agent concentration, cationic or anionic stabilizer concentration. . For example, metal particles having a minimum particle size can be obtained when prepared at an optimal mixing ratio, and metal particles having a larger particle size can be obtained by slightly deviating from this optimal mixing ratio. .
金属イオンの還元反応は、ミセル中で行ってもよい。具体的には、油中水滴（Ｗ／Ｏ型）エマルションの水滴中で行ってもよい。この場合、金属イオンの還元反応が限られた大きさの水滴内で進行することとなり、水滴の大きさに応じた金属粒子が得られる。従って、エマルションの水滴の大きさを制御することにより、例えば、小さい粒子径の金属粒子を得ることが可能となる。 The metal ion reduction reaction may be performed in a micelle. Specifically, it may be performed in water droplets of a water-in-oil (W / O type) emulsion. In this case, the reduction reaction of the metal ions proceeds in a limited size water droplet, and metal particles corresponding to the size of the water droplet can be obtained. Therefore, by controlling the size of the water droplets in the emulsion, for example, metal particles having a small particle diameter can be obtained.
カチオン性安定化剤またはアニオン性安定化剤の存在下で金属イオンを還元させることにより得られた正荷電金属粒子と負荷電金属粒子は、比較的粒径の揃った小粒子径のものとなる。例えば、平均粒子径が５ｎｍ以上５００ｎｍ以下（好ましくは１０ｎｍ以上２００ｎｍ以下であり、より好ましくは１００ｎｍ以下である）の正荷電金属粒子と負荷電金属粒子を容易に得ることができる。なお本発明において、正荷電無機粒子と負荷電無機粒子の平均粒子径は、動的光散乱法により測定した流体力学的直径を用いる。 Positively charged metal particles and negatively charged metal particles obtained by reducing metal ions in the presence of a cationic stabilizer or an anionic stabilizer have a relatively small particle size. . For example, positively charged metal particles and negatively charged metal particles having an average particle size of 5 nm to 500 nm (preferably 10 nm to 200 nm, more preferably 100 nm or less) can be easily obtained. In the present invention, the hydrodynamic diameter measured by the dynamic light scattering method is used as the average particle diameter of the positively charged inorganic particles and the negatively charged inorganic particles.
本発明の製造方法は、無機粒子として金属酸化物を用いることも好ましい。無機粒子として金属酸化物を用いる場合、正荷電無機粒子は正荷電金属酸化物粒子となり、負荷電無機粒子は負荷電金属酸化物粒子となる。金属酸化物としては、アルミナ、シリカ、アルミナ−シリカ、チタニア、ジルコニア等が挙げられる。 In the production method of the present invention, it is also preferable to use a metal oxide as the inorganic particles. When a metal oxide is used as the inorganic particles, the positively charged inorganic particles are positively charged metal oxide particles, and the negatively charged inorganic particles are negatively charged metal oxide particles. Examples of the metal oxide include alumina, silica, alumina-silica, titania, zirconia and the like.
無機粒子として金属酸化物を用いる場合、金属酸化物粒子をカップリング剤（例えば、シランカップリング剤、チタネート系カップリング剤、リン酸系カップリング剤）で処理することにより、正荷電金属酸化物粒子と負荷電金属酸化物粒子を製造することができる。カップリング剤は水酸基やアルコキシ基等の脱水縮合可能な置換基を有していることが好ましく、金属酸化物をカップリング剤で処理することにより、カップリング剤の水酸基やアルコキシ基等が金属酸化物表面の水酸基と反応して、カップリング剤を金属酸化物表面に導入することができる。このとき、カップリング剤がカチオン性基またはアニオン性基を有していれば、金属酸化物粒子に正電荷または負電荷を与えることができる。また、金属酸化物表面に導入したカップリング剤にアニオン性基またはカチオン性基を有する化合物を反応させることにより、正電荷または負電荷を有する金属酸化物粒子を製造することもできる。カチオン性基とアニオン性基としては、上記に説明した置換基が挙げられる。 When a metal oxide is used as the inorganic particles, the metal oxide particles are treated with a coupling agent (for example, a silane coupling agent, a titanate coupling agent, or a phosphoric acid coupling agent) to thereby obtain a positively charged metal oxide. Particles and negatively charged metal oxide particles can be produced. The coupling agent preferably has a substituent capable of dehydration condensation such as a hydroxyl group or an alkoxy group. By treating the metal oxide with a coupling agent, the hydroxyl group or alkoxy group of the coupling agent is oxidized with metal. A coupling agent can be introduced to the surface of the metal oxide by reacting with a hydroxyl group on the surface of the object. At this time, if the coupling agent has a cationic group or an anionic group, a positive charge or a negative charge can be given to the metal oxide particles. Moreover, the metal oxide particle which has a positive charge or a negative charge can also be manufactured by making the compound which has an anionic group or a cationic group react with the coupling agent introduce | transduced on the metal oxide surface. Examples of the cationic group and the anionic group include the substituents described above.
無機粒子として金属酸化物を用いる場合、用いる金属酸化物の粒子径に応じて、得られる正荷電金属酸化物粒子と負荷電金属酸化物粒子の粒子径を変えることができる。金属酸化物は市販のものを用いてもよく、自ら製造してもよい。後者の場合、例えば、アルコキシシランを脱水縮合することによりシリカ粒子を製造することができ、この際の反応条件を適宜調整することでシリカ粒子（金属酸化物）の粒子径を変えることができる。 When a metal oxide is used as the inorganic particles, the particle diameters of the positively charged metal oxide particles and the negatively charged metal oxide particles obtained can be changed according to the particle diameter of the metal oxide used. A commercially available metal oxide may be used, or it may be produced by itself. In the latter case, for example, silica particles can be produced by dehydrating and condensing alkoxysilane, and the particle size of the silica particles (metal oxide) can be changed by appropriately adjusting the reaction conditions.
支持基材を浸漬する正荷電無機粒子を含有する溶液は、上記に説明した正荷電無機粒子が溶媒に分散した溶液であれば特に限定されない。同様に、支持基材を浸漬する負荷電無機粒子を含有する溶液は、上記に説明した負荷電無機粒子が溶媒に分散した溶液であれば特に限定されない。正荷電無機粒子と負荷電無機粒子の分散状態は均一であっても不均一であってもよいが、得られる分離膜の品質を安定にするために、均一であることがより望ましい。正荷電無機粒子または負荷電無機粒子を含有する溶液の溶媒は特に限定されないが、水を用いるのが簡便である。 The solution containing the positively charged inorganic particles for immersing the supporting substrate is not particularly limited as long as the positively charged inorganic particles described above are dispersed in a solvent. Similarly, the solution containing the negatively charged inorganic particles for immersing the supporting substrate is not particularly limited as long as the negatively charged inorganic particles described above are dispersed in a solvent. The dispersion state of the positively charged inorganic particles and the negatively charged inorganic particles may be uniform or nonuniform, but it is more desirable to be uniform in order to stabilize the quality of the obtained separation membrane. The solvent of the solution containing positively charged inorganic particles or negatively charged inorganic particles is not particularly limited, but it is convenient to use water.
支持基材を正荷電無機粒子または負荷電無機粒子を含有する溶液に浸漬することにより、支持基材上に正荷電無機粒子または負荷電無機粒子が付着する。支持基材を正荷電無機粒子または負荷電無機粒子を含有する溶液に浸漬する時間は特に限定されない。本発明の製造方法によれば、正荷電無機粒子と負荷電無機粒子がクーロン力で互いに引き合って支持基材上に積層するため、支持基材を浸漬する時間が短くても、支持基材上に正荷電無機粒子と負荷電無機粒子を好適に付着させることができる。支持基材を正荷電無機粒子または負荷電無機粒子を含有する溶液に浸漬する時間（１回当たりの浸漬時間）は、例えば、１秒間〜１０分間の範囲で行えばよい。 By immersing the supporting substrate in a solution containing positively charged inorganic particles or negatively charged inorganic particles, the positively charged inorganic particles or negatively charged inorganic particles adhere to the supporting substrate. The time for immersing the support substrate in the solution containing positively charged inorganic particles or negatively charged inorganic particles is not particularly limited. According to the production method of the present invention, the positively charged inorganic particles and the negatively charged inorganic particles attract each other with Coulomb force and are laminated on the support base material. The positively charged inorganic particles and the negatively charged inorganic particles can be suitably attached. What is necessary is just to perform the time (immersion time per time) which immerses a support base material in the solution containing a positively charged inorganic particle or a negatively charged inorganic particle in the range of 1 second-10 minutes, for example.
支持基材を正荷電無機粒子または負荷電無機粒子を含有する溶液に浸漬する温度も特に限定されず、正荷電無機粒子または負荷電無機粒子を含有する溶液が液体状態を維持する温度であればよい。なお、支持基材の浸漬作業を簡便に行う点から、浸漬は室温で行うのが好ましい。 The temperature at which the support substrate is immersed in the solution containing positively charged inorganic particles or negatively charged inorganic particles is not particularly limited as long as the solution containing positively charged inorganic particles or negatively charged inorganic particles maintains a liquid state. Good. In addition, it is preferable to perform immersion at room temperature from the point which performs the immersion operation of a support base material simply.
支持基材は、正荷電無機粒子または負荷電無機粒子を含有する溶液を撹拌しながら、当該溶液に浸漬することが好ましい。このように支持基材を正荷電無機粒子または負荷電無機粒子を含有する溶液に浸漬することで、支持基材上に正荷電無機粒子または負荷電無機粒子が均一に付着しやすくなる。 The supporting substrate is preferably immersed in the solution while stirring the solution containing positively charged inorganic particles or negatively charged inorganic particles. Thus, by immersing the supporting substrate in a solution containing positively charged inorganic particles or negatively charged inorganic particles, the positively charged inorganic particles or negatively charged inorganic particles easily adhere uniformly on the supporting substrate.
支持基材は、正荷電無機粒子を含有する溶液と負荷電無機粒子を含有する溶液のどちらを先に浸漬してもよいが、支持基材の表面電荷を考慮して、これとは反対の電荷を有する無機粒子を含有する溶液に最初に支持基材を浸漬することが好ましい。例えば、金属酸化物製の支持基材を使用する場合は一般に、正荷電無機粒子を含有する溶液に最初に支持基材を浸漬させることが好ましい。 The support substrate may be immersed first in either a solution containing positively charged inorganic particles or a solution containing negatively charged inorganic particles, but the opposite is considered in consideration of the surface charge of the support substrate. It is preferable to first immerse the supporting substrate in a solution containing inorganic particles having a charge. For example, when using a metal oxide support substrate, it is generally preferable to first immerse the support substrate in a solution containing positively charged inorganic particles.
本発明の製造方法では、支持基材を正荷電無機粒子または負荷電無機粒子を含有する溶液に交互に浸漬することにより、支持基材上に正荷電無機粒子と負荷電無機粒子が交互に付着する。支持基材を、正荷電無機粒子を含有する溶液と負荷電無機粒子を含有する溶液に浸漬する回数は、得られる分離膜の分離性能や透水量（膜透過流束）を勘案して適宜設定すればよい。浸漬回数が少なすぎる場合は分離膜が所望する分離性能を発揮しにくくなり、逆に浸漬回数が多すぎる場合は透水量が減るおそれがあることから、浸漬回数は、得られる分離膜の分離性能と透水量（膜透過流束）のバランスを見ながら適宜調整することが好ましい。 In the production method of the present invention, the positively charged inorganic particles and the negatively charged inorganic particles are alternately attached on the support base material by alternately immersing the support base material in a solution containing positively charged inorganic particles or negatively charged inorganic particles. To do. The number of times the support substrate is immersed in a solution containing positively charged inorganic particles and a solution containing negatively charged inorganic particles is appropriately set in consideration of the separation performance of the separation membrane and the water permeability (membrane permeation flux). do it. If the number of immersions is too small, the separation membrane will not easily exhibit the desired separation performance. Conversely, if the number of immersions is too large, the water permeability may decrease, so the number of immersions is the separation performance of the resulting separation membrane. It is preferable to adjust appropriately while observing the balance between the amount of water and the amount of water permeation (membrane permeation flux).
支持基材を正荷電無機粒子を含有する溶液に浸漬した後、あるいは、支持基材を負荷電無機粒子を含有する溶液に浸漬した後、支持基材は適宜洗浄することが好ましい。例えば、水やアルコール等の洗浄液で支持基材を洗浄することが好ましい。このように支持基材を洗浄することにより、支持基材上の余剰の正荷電無機粒子または負荷電無機粒子を含有する溶液を除去して、次に浸漬する溶液の汚染を抑えることができる。また、支持基材を洗浄後、支持基材を乾燥させて洗浄液を除去することが好ましい。 It is preferable that the support substrate is appropriately washed after the support substrate is immersed in a solution containing positively charged inorganic particles or after the support substrate is immersed in a solution containing negatively charged inorganic particles. For example, it is preferable to wash the supporting substrate with a washing liquid such as water or alcohol. By washing the support substrate in this manner, the solution containing excess positively charged inorganic particles or negatively charged inorganic particles on the support substrate can be removed, and contamination of the solution to be immersed next can be suppressed. In addition, after washing the support substrate, it is preferable to dry the support substrate and remove the cleaning liquid.
本発明の分離膜の製造方法によれば、支持基材を、正荷電無機粒子を含有する溶液と負荷電無機粒子を含有する溶液に交互に浸漬することにより、支持基材上に正荷電無機粒子と負荷電無機粒子を交互に積層させることができる。その結果、支持基材上に、正荷電無機粒子と負荷電無機粒子による分離層を形成させることができる。本発明によれば、支持基材上に積層させる正荷電無機粒子と負荷電無機粒子の粒子径や積層数を調整することにより、分離性能が高度に制御され、高い透過性能を有する分離膜を得ることが可能となる。 According to the method for producing a separation membrane of the present invention, a support substrate is alternately immersed in a solution containing positively charged inorganic particles and a solution containing negatively charged inorganic particles, thereby positively charged inorganic on the support substrate. Particles and negatively charged inorganic particles can be alternately stacked. As a result, a separation layer composed of positively charged inorganic particles and negatively charged inorganic particles can be formed on the support substrate. According to the present invention, by adjusting the particle diameter and the number of layers of the positively charged inorganic particles and the negatively charged inorganic particles to be laminated on the support substrate, the separation performance is highly controlled, and the separation membrane having high permeation performance is obtained. Can be obtained.
また、得られた分離膜の表面が電荷を帯びたものとなるため、分離膜表面の親水性が高まり、水処理に適用した場合などはファウリングの低減効果が期待できる。 Further, since the surface of the obtained separation membrane is charged, the hydrophilicity of the separation membrane surface is increased, and when applied to water treatment, an effect of reducing fouling can be expected.
本発明の製造方法により得られた分離膜は、精密ろ過膜（ＭＦ膜）や限外ろ過膜（ＵＦ膜）として一般に使用される用途に適用することができる。例えば、廃水（例えば、下水、し尿、畜産糞尿、厨房排水、工場排水、埋立浸出水、それらの処理におけるプロセス排水）処理、浄水処理、飲料品製造、有用物質の分離回収等に適用することができる。また、空気清浄フィルター等の気固分離を目的とした用途にも適用可能である。 The separation membrane obtained by the production method of the present invention can be applied to applications generally used as a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane). For example, it can be applied to wastewater (for example, sewage, human waste, livestock manure, kitchen wastewater, factory wastewater, landfill leachate, process wastewater in those treatments) treatment, water purification treatment, beverage production, separation and recovery of useful substances, etc. it can. Moreover, it is applicable also to the use for the purpose of gas-solid separation, such as an air purifying filter.
以下に、実施例を示すことにより本発明を更に詳細に説明するが、本発明の範囲はこれらに限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited thereto.
（１）分離膜の作製
（１−１）カチオン性ＰＥＩ−Ａｇ粒子の調製
ビーカーに、ポリエチレンイミン（和光純薬工業社製、Ｍｗ：１，８００）４０μｍｏｌと、ＮａＢＨ4 １６ｍｇを測り取り、超純水（Ｍｉｌｌｉ−Ｑ（登録商標）水）を１００ｍＬ加えてスターラーで撹拌させて溶解し、ＰＥＩ溶液を調製した。別に１ｍＭ ＡｇＮＯ3水溶液５０ｍＬを調製し、シリンジポンプ（ＫＤＳ社製、ＫＤＳ１００ １本架シリンジポンプ）を用いて、撹拌下でＰＥＩ溶液に１５分間かけて滴下し、滴下終了後も１時間撹拌し続けた。その結果、溶液中に、ポリエチレンイミンにより正荷電されたＡｇ粒子（カチオン性ＰＥＩ−Ａｇ粒子）が生成した。カチオン性ＰＥＩ−Ａｇ粒子の分散状態の流体力学的直径を動的光散乱法により測定したところ、３６．３ｎｍ（キュムラント法による多分散指数は０．３１）であった。なお、動的光散乱法による流体力学的直径の測定は、大塚電子株式会社製のＥＬＳＺ−２を用いて行った。
(1) Preparation of separation membrane (1-1) Preparation of cationic PEI-Ag particles In a beaker, 40 μmol of polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd., Mw: 1,800) and 16 mg of NaBH 4 were measured. 100 mL of pure water (Milli-Q (registered trademark) water) was added and dissolved by stirring with a stirrer to prepare a PEI solution. Separately, 50 mL of a 1 mM AgNO 3 aqueous solution was prepared and dropped into the PEI solution over 15 minutes under stirring using a syringe pump (KDS, KDS100 single-head syringe pump). It was. As a result, Ag particles (cationic PEI-Ag particles) positively charged with polyethyleneimine were generated in the solution. When the hydrodynamic diameter of the cationic PEI-Ag particles in a dispersed state was measured by a dynamic light scattering method, it was 36.3 nm (polydispersity index by cumulant method was 0.31). In addition, the measurement of the hydrodynamic diameter by the dynamic light scattering method was performed using ELSZ-2 manufactured by Otsuka Electronics Co., Ltd.
（１−２）アニオン性ＰＳＳ−Ａｇ粒子の調製
ビーカーに、ポリ（４−スチレンスルホン酸ナトリウム）（Ａｌｄｒｉｃｈ社、３０質量％、Ｍｗ：２００，０００）３０μｍｏｌと、ＮａＢＨ4 ７．６ｍｇを測り取り、超純水（Ｍｉｌｌｉ−Ｑ（登録商標）水）を１００ｍＬ加えてスターラーで撹拌させて溶解し、ＰＳＳ溶液を調製した。別に１ｍＭ ＡｇＮＯ3水溶液５０ｍＬを調製し、シリンジポンプ（ＫＤＳ社製、ＫＤＳ１００ １本架シリンジポンプ）を用いて、撹拌下でＰＳＳ溶液に１５分間かけて滴下し、滴下終了後も１時間撹拌し続けた。その結果、溶液中に、ポリ（４−スチレンスルホン酸）により負荷電されたＡｇ粒子（アニオン性ＰＳＳ−Ａｇ粒子）が生成した。アニオン性ＰＳＳ−Ａｇ粒子の分散状態の流体力学的直径を動的光散乱法により測定したところ、２２．２ｎｍ（キュムラント法による多分散指数は０．２５）であった。
(1-2) Preparation of Anionic PSS-Ag Particles In a beaker, 30 μmol of poly (4-styrenesulfonate sodium) (Aldrich, 30% by mass, Mw: 200,000) and 7.6 mg of NaBH 4 were measured. 100 mL of ultrapure water (Milli-Q (registered trademark) water) was added and dissolved by stirring with a stirrer to prepare a PSS solution. Separately, 50 mL of a 1 mM AgNO 3 aqueous solution was prepared, and was dropped into the PSS solution over 15 minutes under stirring using a syringe pump (KDS, KDS100 single-head syringe pump). It was. As a result, Ag particles (anionic PSS-Ag particles) negatively charged with poly (4-styrenesulfonic acid) were produced in the solution. When the hydrodynamic diameter of the dispersed state of the anionic PSS-Ag particles was measured by a dynamic light scattering method, it was 22.2 nm (polydispersity index by cumulant method was 0.25).
（１−３）Ａｇ粒子積層膜の作製
上記（１−１）で調製したカチオン性ＰＥＩ−Ａｇ粒子含有溶液４０ｍＬに１００ｍＭ ＮａＣｌ溶液を８８３μＬ添加し、スターラーで撹拌しながら、アルミナ支持基材（Ｗｈａｔｍａｎ社製、Ａｎｏｄｉｓｃ Ｓｕｐｐｏｒｔｅｄ Ｆｉｌｔｅｒｓ、直径２５ｍｍ、孔径０．０２μｍ）を３０秒間浸漬した。浸漬後、アルミナ支持基材を取り出し、超純水に１５秒間浸漬することを２回繰り返し、さらにエタノールに１０秒間浸漬した後、窒素ガスでアルミナ支持基材（正確にはカチオン性ＰＥＩ−Ａｇ粒子層が形成されたアルミナ支持基材）の表面を乾燥させた。
(1-3) Production of Ag Particle Laminated Film 883 μL of 100 mM NaCl solution was added to 40 mL of the cationic PEI-Ag particle-containing solution prepared in (1-1) above, and while stirring with a stirrer, an alumina support substrate (Whatman Anodisc Supported Filters, diameter 25 mm, pore diameter 0.02 μm) was immersed for 30 seconds. After dipping, the alumina support substrate is taken out and immersed in ultrapure water for 15 seconds twice. Further, after dipping in ethanol for 10 seconds, the alumina support substrate (accurately, cationic PEI-Ag particles with nitrogen gas) The surface of the alumina support substrate on which the layer was formed was dried.
次いで、上記（１−２）で調製したアニオン性ＰＳＳ−Ａｇ粒子含有溶液４０ｍＬに１００ｍＭ ＮａＣｌ溶液を２７０μＬ添加し、スターラーで撹拌しながら、カチオン性ＰＥＩ−Ａｇ粒子が積層したアルミナ支持基材を３０秒間浸漬した。浸漬後、アルミナ支持基材を取り出し、超純水に１５秒間浸漬することを２回繰り返し、さらにエタノールに１０秒間浸漬した後、窒素ガスでアルミナ支持基材（正確には最表面にアニオン性ＰＳＳ−Ａｇ粒子層が形成されたアルミナ支持基材）の表面を乾燥させた。 Next, 270 μL of 100 mM NaCl solution was added to 40 mL of the anionic PSS-Ag particle-containing solution prepared in (1-2) above, and 30 alumina support base materials on which cationic PEI-Ag particles were laminated while stirring with a stirrer. Soaked for 2 seconds. After dipping, the alumina support substrate is taken out and immersed in ultrapure water for 15 seconds twice. Further, after dipping in ethanol for 10 seconds, the alumina support substrate (exactly an anionic PSS on the outermost surface) is added with nitrogen gas. -The surface of the alumina support substrate on which the Ag particle layer was formed was dried.
次いで、アニオン性ＰＳＳ−Ａｇ粒子が積層したアルミナ支持基材を、上記（１−１）で調製したカチオン性ＰＥＩ−Ａｇ粒子含有溶液４０ｍＬに１００ｍＭ ＮａＣｌ溶液を８８３μＬ添加した溶液に再び浸漬した。このように、アルミナ支持基材をカチオン性ＰＥＩ−Ａｇ粒子含有溶液とアニオン性ＰＳＳ−Ａｇ粒子含有溶液に交互に浸漬させることにより、ＰＥＩ−Ａｇ粒子とＰＳＳ−Ａｇ粒子をアルミナ支持基材上に交互に積層させた。アルミナ支持基材は、カチオン性ＰＥＩ−Ａｇ粒子含有溶液とアニオン性ＰＳＳ−Ａｇ粒子含有溶液に、合計２０回、４０回、６０回、または８０回（すなわちそれぞれの溶液にはこの半分の回数）浸漬させ、Ａｇ粒子が積層した分離膜を製造した。なお、このように得られた分離膜をそれぞれ、２０回浸漬膜、４０回浸漬膜、６０回浸漬膜、８０回浸漬膜と称する。 Next, the alumina support base material on which the anionic PSS-Ag particles were laminated was immersed again in a solution obtained by adding 883 μL of a 100 mM NaCl solution to 40 mL of the cationic PEI-Ag particle-containing solution prepared in (1-1) above. In this manner, the PEI-Ag particles and the PSS-Ag particles are placed on the alumina support substrate by alternately immersing the alumina support substrate in the cationic PEI-Ag particle-containing solution and the anionic PSS-Ag particle-containing solution. The layers were alternately stacked. The alumina support substrate can be added to the cationic PEI-Ag particle-containing solution and the anionic PSS-Ag particle-containing solution for a total of 20, 40, 60, or 80 times (ie, half the number of times for each solution). A separation membrane in which Ag particles were laminated was produced by immersion. The separation membranes thus obtained are referred to as a 20-time immersion membrane, a 40-time immersion membrane, a 60-time immersion membrane, and an 80-time immersion membrane, respectively.
（２）分離膜の観察
（２−１）ＦＥ−ＳＥＭ観察
６０回浸漬膜の表面と断面を、電界放出形走査電子顕微鏡（日本電子社製、ＪＳＭ−７５００Ｆ）を用いて観察した。また、アルミナ支持基材の表面も、同様に電界放出形走査電子顕微鏡を用いて観察した。なお電界放出形走査電子顕微鏡観察に当たり、６０回浸漬膜とアルミナ支持基材は、オスミウムコーター（メイワフォーシス社製、Ｎｅｏｃ−ＳＴＢ）によりオスミウムで表面被覆した。
(2) Observation of separation membrane (2-1) FE-SEM observation The surface and cross section of the 60-time immersion membrane were observed using a field emission scanning electron microscope (JSM-7500F, manufactured by JEOL Ltd.). Similarly, the surface of the alumina support substrate was observed using a field emission scanning electron microscope. In the field emission scanning electron microscope observation, the 60-times immersed film and the alumina support substrate were covered with osmium by an osmium coater (Neoc-STB, manufactured by Meiwa Forsys).
（２−２）観察結果
６０回浸漬膜とアルミナ支持基材の表面のＦＥ−ＳＥＭ観察画像を図１に示した。図１（ａ）は６０回浸漬膜の表面ＦＥ−ＳＥＭ観察画像を表し、図１（ｂ）はアルミナ支持基材の表面ＦＥ−ＳＥＭ観察画像を表す。Ａｇ粒子は支持基材の全面を覆っており、表面に堆積したＡｇ粒子は２０ｎｍ〜４０ｎｍ程度の粒子径を有していた。この粒子径は、使用したカチオン性ＰＥＩ−Ａｇ粒子とアニオン性ＰＳＳ−Ａｇ粒子の動的光散乱法により測定された流体力学的直径の測定結果とほぼ一致した。
(2-2) Observation Results FE-SEM observation images of the 60-time immersion film and the surface of the alumina support substrate are shown in FIG. FIG. 1A shows a surface FE-SEM observation image of a 60-time immersion film, and FIG. 1B shows a surface FE-SEM observation image of an alumina support substrate. The Ag particles covered the entire surface of the supporting substrate, and the Ag particles deposited on the surface had a particle diameter of about 20 nm to 40 nm. This particle diameter almost coincided with the measurement result of the hydrodynamic diameter measured by the dynamic light scattering method of the used cationic PEI-Ag particles and anionic PSS-Ag particles.
図２には、６０回浸漬膜の断面のＦＥ−ＳＥＭ観察画像を示した。６０回浸漬膜の膜表面には、Ａｇ粒子が積層することにより、厚さ５０ｎｍ程度の分離層（図２において矢印で挟まれた部分）が形成されていた。 In FIG. 2, the FE-SEM observation image of the cross section of a 60 times immersion film was shown. A separation layer (a portion sandwiched between arrows in FIG. 2) having a thickness of about 50 nm was formed on the film surface of the 60-time immersion film by laminating Ag particles.
図３には、２０回浸漬膜、４０回浸漬膜、６０回浸漬膜、８０回浸漬膜のそれぞれの分離膜について、分離層の厚さの測定結果をグラフに示した。図３から分かるように、浸漬回数にほぼ比例して分離層の厚さが増加する結果となった。 In FIG. 3, the measurement result of the thickness of the separation layer was shown in the graph about each separation membrane of the 20-time immersion membrane, the 40-time immersion membrane, the 60-time immersion membrane, and the 80-time immersion membrane. As can be seen from FIG. 3, the thickness of the separation layer increased in proportion to the number of immersions.
（３）分離膜の性能評価
（３−１）試験方法
クロスフロー式透水試験装置を用いて、透水量とデキストラン阻止率を測定した。透水量の測定は超純水を用い、阻止率の測定は濃度１質量％のデキストランと濃度１質量％のエチレングリコールの混合溶液を用いて行った。デキストランは、分子量３５，０００〜４５，０００（３５ｋＤａ）、１００，０００〜２００，０００（１００ｋＤａ）、４００，０００〜５００，０００（５００ｋＤａ）（以上、Ｓｉｇｍａ−Ａｌｄｒｉｃｈ社製）と分子量１５，０００〜２０，０００（１５ｋＤａ）（ナカライテスク社製）の各種を用いた。超純水または各種混合溶液をクロスフロー式透水試験装置に導入し、分離膜の一次側に存在する超純水または各種混合溶液を５００ｒｐｍで撹拌しながら０．２５ＭＰａで加圧し、膜透過液を得た。膜透過液は３回採取し、それぞれ得られた値の平均値を用い、透水量（ｍ3／（ｍ2・ｄａｙ・ａｔｏｍ））と阻止率を算出した。阻止率は、ＧＰＣ（ゲル浸透クロマトグラフィー）を用いて、エチレングリコールを標準物質としてデキストランの阻止率を算出した。
(3) Performance Evaluation of Separation Membrane (3-1) Test Method The amount of water permeation and the dextran blocking rate were measured using a cross flow type water permeation test device. The amount of water permeation was measured using ultrapure water, and the blocking rate was measured using a mixed solution of dextran having a concentration of 1% by mass and ethylene glycol having a concentration of 1% by mass. Dextran has a molecular weight of 35,000 to 45,000 (35 kDa), 100,000 to 200,000 (100 kDa), 400,000 to 500,000 (500 kDa) (above, manufactured by Sigma-Aldrich) and a molecular weight of 15,000. Various types of ˜20,000 (15 kDa) (manufactured by Nacalai Tesque) were used. Ultrapure water or various mixed solutions are introduced into a cross-flow type water permeability test apparatus, and ultrapure water or various mixed solutions present on the primary side of the separation membrane are pressurized at 0.25 MPa while stirring at 500 rpm, Obtained. The membrane permeate was sampled three times, and the average value of the obtained values was used to calculate the amount of water permeation (m 3 / (m 2 · day · atom)) and the blocking rate. The inhibition rate was calculated by using GPC (gel permeation chromatography) and ethylene glycol as a standard substance.
（３−２）評価結果
図４に、２０回浸漬膜、４０回浸漬膜、６０回浸漬膜、８０回浸漬膜のそれぞれの分離膜についての、透水量とデキストラン阻止率の試験結果を示した。６０回浸漬膜は、１０（ｍ3／（ｍ2・ｄａｙ・ａｔｏｍ））程度の透水量で、分画分子量５００ｋＤａ程度の分離性能を示した。一方で、２０回浸漬膜と４０回浸漬膜では分離性能を示さなかった。以上の結果より、本発明の製造方法により、高度に分離性能が制御された分離膜を得ることができることが示された。
(3-2) Evaluation Results FIG. 4 shows the test results of the water permeation rate and the dextran blocking rate for the separation membranes of the 20-time immersion membrane, the 40-time immersion membrane, the 60-time immersion membrane, and the 80-time immersion membrane. . 60 dips film, at 10 (m 3 / (m 2 · day · atom)) about the amount of water permeation showed fractional molecular weight 500kDa about separation performance. On the other hand, the separation performance was not shown in the 20-time immersion membrane and the 40-time immersion membrane. From the above results, it was shown that a separation membrane with highly controlled separation performance can be obtained by the production method of the present invention.
本発明によれば、高度に分離性能が制御された分離膜を得ることができる。得られた分離膜は、廃水処理、浄水処理、有用物質の分離回収、気固分離処理等に適用することができる。 According to the present invention, a separation membrane with highly controlled separation performance can be obtained. The obtained separation membrane can be applied to wastewater treatment, water purification treatment, separation and recovery of useful substances, gas-solid separation treatment, and the like.
Claims (4)
前記正荷電無機粒子が、カチオン性安定化剤の存在下で金属イオンを還元させることにより得られるものであり、
前記負荷電無機粒子が、アニオン性安定化剤の存在下で金属イオンを還元させることにより得られるものである請求項１または２に記載の分離膜の製造方法。 The inorganic particles are metal particles;
The positively charged inorganic particles are obtained by reducing metal ions in the presence of a cationic stabilizer,
The method for producing a separation membrane according to claim 1 or 2, wherein the negatively charged inorganic particles are obtained by reducing metal ions in the presence of an anionic stabilizer.
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| WO2018038013A1 (en) * | 2016-08-22 | 2018-03-01 | 国立大学法人神戸大学 | Nanosheet laminate type separation membrane and method for producing same |
| WO2021200690A1 (en) * | 2020-03-30 | 2021-10-07 | 栗田工業株式会社 | Particulate removal apparatus |
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| JPH08269217A (en) * | 1995-03-31 | 1996-10-15 | Asahi Chem Ind Co Ltd | Bipolar membrane |
| JP2006187731A (en) * | 2005-01-06 | 2006-07-20 | Kurita Water Ind Ltd | Separation membrane and water treatment apparatus |
| JP2008188513A (en) * | 2007-02-02 | 2008-08-21 | Hitachi Chem Co Ltd | Method and device for manufacturing base material with interlaminated film |
| JP2011016096A (en) * | 2009-07-09 | 2011-01-27 | Kobe Univ | Composite semipermeable membrane |
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| JPH08269217A (en) * | 1995-03-31 | 1996-10-15 | Asahi Chem Ind Co Ltd | Bipolar membrane |
| JP2006187731A (en) * | 2005-01-06 | 2006-07-20 | Kurita Water Ind Ltd | Separation membrane and water treatment apparatus |
| JP2008188513A (en) * | 2007-02-02 | 2008-08-21 | Hitachi Chem Co Ltd | Method and device for manufacturing base material with interlaminated film |
| JP2011016096A (en) * | 2009-07-09 | 2011-01-27 | Kobe Univ | Composite semipermeable membrane |
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| WO2018038013A1 (en) * | 2016-08-22 | 2018-03-01 | 国立大学法人神戸大学 | Nanosheet laminate type separation membrane and method for producing same |
| JPWO2018038013A1 (en) * | 2016-08-22 | 2019-07-11 | 国立大学法人神戸大学 | Nanosheet laminated separation membrane and method of manufacturing the same |
| WO2021200690A1 (en) * | 2020-03-30 | 2021-10-07 | 栗田工業株式会社 | Particulate removal apparatus |
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