JP6433737B2 - Preparation method of ultrafiltration membrane - Google Patents

Preparation method of ultrafiltration membrane Download PDF

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JP6433737B2
JP6433737B2 JP2014193932A JP2014193932A JP6433737B2 JP 6433737 B2 JP6433737 B2 JP 6433737B2 JP 2014193932 A JP2014193932 A JP 2014193932A JP 2014193932 A JP2014193932 A JP 2014193932A JP 6433737 B2 JP6433737 B2 JP 6433737B2
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菅原 広
広 菅原
史貴 市原
史貴 市原
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Description

本発明は、高い除粒子性能を有する限外ろ過膜の調製方法に関する。この調製方法により得られた限外ろ過膜限外ろ過膜装置に用いることができる。この限外ろ過膜装置は、超純水のろ過装置として利用することができる。この限外ろ過膜装置を、超純水製造装置内のサブシステムの末端又はその近傍に設置することで、微粒子数の少ない超純水を提供することが可能となる。 The present invention relates to a method for preparing an ultrafiltration membrane having high particle removal performance . Ultrafiltration membrane obtained by this preparation method can be used for ultrafiltration membrane apparatus. This ultrafiltration membrane device can be used as a filtration device for ultrapure water. By installing this ultrafiltration membrane device at or near the end of the subsystem in the ultrapure water production device, it is possible to provide ultrapure water with a small number of fine particles.

半導体製造産業においては、不純物を高度に除去した超純水を用いてシリコンウエハの洗浄等が行われている。超純水は、一般に、原水(河川水、地下水、工業用水)中に含まれる懸濁物質や有機物等の一部を前処理工程で除去した後、その処理水を一次純水システム及び二次純水システム(サブシステム)で順次処理することによって製造され、ウエハ洗浄を行うユースポイントに供給される。超純水製造装置には、一般的に、超純水から微粒子、菌、コロイド、高分子化合物等を除去するためのろ過膜装置が設置されている。   In the semiconductor manufacturing industry, silicon wafers are cleaned using ultrapure water from which impurities are highly removed. Ultra-pure water generally removes part of suspended matter and organic matter contained in raw water (river water, groundwater, industrial water) in the pretreatment process, and then treats the treated water with the primary pure water system and the secondary water. Manufactured by sequential processing in a pure water system (subsystem), and supplied to a use point for wafer cleaning. The ultrapure water production apparatus is generally provided with a filtration membrane device for removing fine particles, bacteria, colloids, polymer compounds, and the like from ultrapure water.

超純水からの微粒子等の除去に用いられるろ過膜装置としては、限外ろ過膜(ultrafiltration membrane:UF膜)や精密ろ過膜(microfiltration membrane)が用いられている。限外ろ過膜は、膜表面の緻密層で微粒子や高分子物質の除去を行うものである。限外ろ過膜のろ過性能は、分画分子量(カットオフ値)により規定されている。この分画分子量は、既知の分子量を有する指標物質をろ過した際に阻止率90%が得られる分子量を示している。一方、精密ろ過膜は、多孔質膜として形成されており、膜表面以外に膜内部(多孔質構造の細孔内部)においても微粒子の除去が行われ、そのろ過性能は、除去率99%程度の標準粒子の粒径による「定格ろ過精度」によって規定されている。(非特許文献1)   As a filtration membrane device used for removing fine particles and the like from ultrapure water, an ultrafiltration membrane (UF membrane) and a microfiltration membrane are used. The ultrafiltration membrane removes fine particles and polymer substances with a dense layer on the membrane surface. The filtration performance of the ultrafiltration membrane is regulated by the fractional molecular weight (cut-off value). This fractionated molecular weight indicates a molecular weight that can give a 90% rejection when an indicator substance having a known molecular weight is filtered. On the other hand, the microfiltration membrane is formed as a porous membrane, and fine particles are removed not only on the membrane surface but also inside the membrane (inside the pores of the porous structure), and the filtration performance is about 99% removal rate. It is defined by the “rated filtration accuracy” based on the standard particle size. (Non-Patent Document 1)

特許文献1には、一次純水製造装置と二次純水製造装置をサブシステムとして有し、処理水中の溶存酸素を低下させて水質を安定化させるための脱気装置を一次純水製造装置に設け、二次純水製造装置の末端に限外ろ過膜装置を配置してユースポイントへ超純水を供給し、使用した残余の超純水を一次純水製造装置に循環する構成を有する超純水製造装置が開示されている。
超純水製造装置において用いられている限外ろ過膜の分画分子量は数千〜数万の範囲にある。
Patent Document 1 discloses a primary pure water production apparatus having a primary pure water production apparatus and a secondary pure water production apparatus as subsystems, and a deaeration device for stabilizing dissolved water by reducing dissolved oxygen in treated water. In addition, an ultrafiltration membrane device is disposed at the end of the secondary pure water production device to supply ultrapure water to the use point, and the remaining ultrapure water used is circulated to the primary pure water production device. An ultrapure water production apparatus is disclosed.
The fractionation molecular weight of the ultrafiltration membrane used in the ultrapure water production apparatus is in the range of thousands to tens of thousands.

特許文献2及び3には、超純水中の微粒子を直接測定する方法が開示されており、特許文献4にはフィルターの除粒子性能の評価方法が開示されている。
一方、超純水中に含まれる微粒子の分布について、非特許文献1には、粒子サイズ(例えば直径)と個数の関係について、粒子の個数が「1/(粒子サイズ)3」との関係で指数関数的に分布する等、粒子サイズが小さくなるにしたがって粒子の個数が増加するとの報告があることが記載され、更に、小さい粒子の個数濃度を測定しなくても、例えば0.1μmよりも大きい粒子の個数濃度を測定することによって、それよりも小さい粒子の個数濃度を推定することが提案されている。
Patent Documents 2 and 3 disclose a method for directly measuring fine particles in ultrapure water, and Patent Document 4 discloses a method for evaluating the particle removal performance of a filter.
On the other hand, regarding the distribution of fine particles contained in ultrapure water, Non-Patent Document 1 describes the relationship between the particle size (for example, diameter) and the number of particles, where the number of particles is “1 / (particle size) 3 ”. It is described that there is a report that the number of particles increases as the particle size decreases, such as an exponential distribution, and even if the number concentration of small particles is not measured, for example, it is less than 0.1 μm. It has been proposed to estimate the number concentration of smaller particles by measuring the number concentration of large particles.

特開平06−312175号公報Japanese Patent Laid-Open No. 06-312175 特開平09−276672号公報JP 09-276672 A 特開2007−70126号公報JP 2007-70126 A 特開2013−31835号公報JP 2013-31835 A

「クリーンテクノロジー」、日本工業出版、2003年5月号、第70頁〜第74頁“Clean Technology”, Nihon Kogyo Publishing, May 2003, pp. 70-74

超純水中の微粒子の分布に関しては、非特許文献1には粒子サイズが小さくなるに従って微粒子の個数が大きな割合で増加する点が示唆されており、超純水中に相当数の粒径が50nm未満の微粒子(sub-50nm微粒子)が含まれている可能性がある。一方、sub-50nm微粒子を計測するためのパーティクルカウンターも提供されているが、超純水中のsub-50nm微粒子の計測における信頼性については、なお検証がなされている段階にある。従って、超純水に含まれるsub-50nm微粒子の分布についての実験値や実測値の詳細な報告例は未だ見当たらないのが現状である。このように、超純水中のsub-50nm微粒子の分布についての情報が十分にない状況において、超純水がsub-50nm微粒子を含む場合に、sub-50nm微粒子を要求される基準まで低減する上での限外ろ過膜の有効性や、限外ろ過膜によってsub-50nm微粒子を超純水から除去する際の技術課題についてこれまで着目されておらず、これらの点に関しての検討すら行われていなかった。すなわち、sub-50nm微粒子を超純水から除去するために、どのような限外ろ過膜やどのような限外ろ過膜装置が有効かどうかについての十分な情報はいまだ得られていない。   Regarding the distribution of fine particles in ultrapure water, Non-Patent Document 1 suggests that the number of fine particles increases at a large rate as the particle size decreases. There is a possibility that fine particles of less than 50 nm (sub-50 nm fine particles) are contained. On the other hand, a particle counter for measuring sub-50nm fine particles is also provided, but the reliability of measuring sub-50nm fine particles in ultrapure water is still being verified. Therefore, there are currently no detailed reports of experimental values or actual measurement values regarding the distribution of sub-50 nm fine particles contained in ultrapure water. In this way, in the situation where there is not enough information about the distribution of sub-50nm fine particles in ultrapure water, when ultrapure water contains sub-50nm fine particles, sub-50nm fine particles are reduced to the required standard Up to now, the effectiveness of ultrafiltration membranes and the technical issues in removing sub-50nm fine particles from ultrapure water using ultrafiltration membranes have not been focused on, and even these points have been studied. It wasn't. That is, sufficient information about what kind of ultrafiltration membrane and what kind of ultrafiltration membrane device is effective for removing sub-50 nm fine particles from ultrapure water has not yet been obtained.

本発明の目的は、簡便な方法により限外ろ過膜の高性能化及び高信頼化を達成し得る限外ろ過膜の調製方法、並びに、かかる調製方法により調製された限外ろ過膜を用いる水処理方法を提供することにある。本発明の更なる目的は、かかる調製方法により調製された限外ろ過膜を有し、高性能及び高信頼性を有し、コストを抑えることができる限外ろ過膜装置を提供することにある。   An object of the present invention is to provide a method for preparing an ultrafiltration membrane capable of achieving high performance and high reliability of an ultrafiltration membrane by a simple method, and water using an ultrafiltration membrane prepared by such a preparation method. It is to provide a processing method. A further object of the present invention is to provide an ultrafiltration membrane device having an ultrafiltration membrane prepared by such a preparation method, having high performance and high reliability, and capable of reducing costs. .

本発明にかかる限外ろ過膜の調製方法は、
超純水中の微粒子を除去するポリスルホン製の限外ろ過膜に、微粒子を含む調製用水を通水して該限外ろ過膜に該微粒子を付加する処理を行い、
前記調製用水に含まれる微粒子のサイズが、5nmから500nmの範囲から選択され、
前記調製用水に含まれる微粒子の前記限外ろ過膜への付加量が、前記限外ろ過の膜面積に対して10%以下である
ことを特徴とする。
The preparation method of the ultrafiltration membrane according to the present invention is as follows:
A process of adding the fine particles to the ultrafiltration membrane by passing water for preparation containing the fine particles through an ultrafiltration membrane made of polysulfone that removes the fine particles in ultrapure water,
The size of the fine particles contained in the preparation water is selected from a range from 5nm to 500 nm,
The amount of the fine particles contained in the preparation water added to the ultrafiltration membrane is 10% or less with respect to the membrane area of the ultrafiltration .

本発明にかかる限外ろ過膜の調製方法及び水処理方法によれば、限外ろ過膜に微粒子を付加するという簡便な処理によって、限外ろ過膜の高性能化を達成することができる。この調製方法により調製された限外ろ過膜を有する限外ろ過膜装置を用いることにより、高性能及び高信頼性を有し、コストを抑えることができる限外ろ過膜装置を提供することができる。   According to the method for preparing an ultrafiltration membrane and the water treatment method according to the present invention, high performance of the ultrafiltration membrane can be achieved by a simple treatment of adding fine particles to the ultrafiltration membrane. By using an ultrafiltration membrane device having an ultrafiltration membrane prepared by this preparation method, it is possible to provide an ultrafiltration membrane device that has high performance and high reliability and can reduce costs. .

本発明にかかる限外ろ過膜の調製用水による処理を行う装置の一例を模式的に示す図である。It is a figure which shows typically an example of the apparatus which performs the process by the water for preparation of the ultrafiltration membrane concerning this invention. 限外ろ過膜装置中で本発明にかかる限外ろ過膜の調製用水による処理を行う場合の限外ろ過膜装置の一例を模式的に示す図である。It is a figure which shows typically an example of the ultrafiltration membrane apparatus in the case of performing the process by the water for preparation of the ultrafiltration membrane concerning this invention in an ultrafiltration membrane apparatus. 超純水装置の構成の一実施形態を説明するためのフロー図である。It is a flowchart for demonstrating one Embodiment of a structure of an ultrapure water apparatus.

本発明にかかる限外ろ過膜の調製方法は、限外ろ過膜の膜面に対して微粒子を付加する工程を有する。   The method for preparing an ultrafiltration membrane according to the present invention includes a step of adding fine particles to the membrane surface of the ultrafiltration membrane.

限外ろ過膜の膜面に対して微粒子を付加し、付加された微粒子が限外ろ過膜の膜面に付着及び/又は固定することによって、限外ろ過膜の除粒子性能を向上させることができる。この限外ろ過膜の除粒子性能の向上は、以下の理由によると本発明者らは考えている。
限外ろ過膜の分離性能の指標として一般的に分画分子量が使われる。分画分子量は、既知の分子量を有する標準物質を透過させて阻止率90%に相当する分子量から定める。即ち、分画分子量5000の限外ろ過膜であれば、分子量5000の物質の90%を捕捉できる。限外ろ過膜の孔径は完全な均一ではなく、通常は分画分子量を規定するメインの孔径を含むバラツキを有している。このメインの孔径を有する孔が孔径分布において最も大きな割合を占めるが、このメインの孔径よりも大きな孔があると、除去対象のサイズの微粒子がそこを通過して除去できない場合が生じる。即ち、規定された分画分子量よりも大きい分子量の物質が捕捉されない可能性がある。そこで、このような大きな孔を微粒子で塞ぐことで限外ろ過膜の完全性を高め、除粒子性能を向上させるとともに、限外ろ過膜の信頼性を高めることができる。更に、限外ろ過膜に通水をすると、水はより大きな孔を通る確率が高くなる、すなわち、ミクロ的な限外ろ過膜の通水のし易さには膜面において分布があり、より大きな孔の周辺への水の流れが形成され易いと考えられる。このため、孔閉鎖用の微粒子を含む調製用水を限外ろ過膜に通水すると、孔閉鎖用の微粒子が、大きな孔に供給される確率が高くなり、大きな孔を効率よく塞ぐことが可能であると考えられる。
By adding fine particles to the membrane surface of the ultrafiltration membrane and attaching and / or fixing the added fine particles to the membrane surface of the ultrafiltration membrane, the particle removal performance of the ultrafiltration membrane can be improved. it can. The present inventors consider that the particle removal performance of the ultrafiltration membrane is improved for the following reason.
The molecular weight cut off is generally used as an index of separation performance of ultrafiltration membranes. The molecular weight cut off is determined from a molecular weight corresponding to a blocking rate of 90% by allowing a standard substance having a known molecular weight to permeate. That is, an ultrafiltration membrane with a molecular weight cut off of 5000 can capture 90% of a substance with a molecular weight of 5000. The pore size of the ultrafiltration membrane is not completely uniform, and usually has a variation including the main pore size that defines the fractional molecular weight. The holes having the main hole diameter occupy the largest ratio in the hole diameter distribution. However, if there is a hole larger than the main hole diameter, there are cases where fine particles having a size to be removed cannot pass through the hole and be removed. That is, there is a possibility that a substance having a molecular weight larger than the prescribed molecular weight cut-off is not captured. Therefore, by closing such a large hole with fine particles, the integrity of the ultrafiltration membrane can be improved, the particle removal performance can be improved, and the reliability of the ultrafiltration membrane can be improved. In addition, when water is passed through the ultrafiltration membrane, the probability of water passing through larger pores increases, that is, the ease of water passing through the microfiltration membrane has a distribution on the membrane surface. It is thought that the flow of water around the large hole is likely to be formed. Therefore, if water for preparation containing fine particles for closing the pores is passed through the ultrafiltration membrane, the probability that the fine particles for closing the pores are supplied to the large pores is increased, and the large pores can be efficiently blocked. It is believed that there is.

上述した通り、孔閉鎖用微粒子は、限外ろ過膜の多数の孔の一部を閉鎖して完全性を上げ(限外ろ過膜の膜表面の緻密層にある大き目の細孔径を塞ぎ、微粒子リークを引き起こす欠陥部分を少なくする)、除粒子性能(排除率)を高める目的で使用する。
孔閉鎖用微粒子の種類は特に限定されるものではなく、対象となる限外ろ過膜やその使用目的に応じて適宜選択することができる。特に、超純水システムの末端又はその近傍に設置する限外ろ過膜装置に対して適用する場合は、低溶出が要求される。したがって、できるだけ少量の微粒子の添加によって狙い通りの効果を発揮するために、溶出量が少ない球状の合成粒子を使用することが好ましい。また、単分散であること又は単分散に近い(実質的に単分散)ことが、孔閉鎖用微粒子の膜への付加率等の調製条件を管理する上で好ましい。
孔閉鎖用微粒子としては、例えば、金粒子(金コロイド)、PSL(ポリスチレンラテックス)粒子、シリカ粒子等があげられる。
As described above, the fine particles for closing the pores improve the integrity by closing some of the pores of the ultrafiltration membrane (the fine pore diameter in the dense layer on the surface of the ultrafiltration membrane is blocked, and the fine particles It is used for the purpose of increasing the particle removal performance (exclusion rate) and reducing the defective portion causing the leak).
The kind of fine particles for pore closure is not particularly limited, and can be appropriately selected according to the intended ultrafiltration membrane and the purpose of use. In particular, when applied to an ultrafiltration membrane device installed at or near the end of an ultrapure water system, low elution is required. Therefore, it is preferable to use spherical synthetic particles with a small amount of elution in order to achieve the intended effect by adding as small a quantity of fine particles as possible. In addition, it is preferable that it is monodisperse or close to monodispersion (substantially monodisperse) in order to manage the preparation conditions such as the addition rate of fine particles for hole closing to the membrane.
Examples of the fine particles for closing a hole include gold particles (gold colloid), PSL (polystyrene latex) particles, and silica particles.

孔閉鎖用微粒子のサイズは、限外ろ過膜の分画分子量と、ろ過処理において目的とされる除粒子性能に応じて設定することができる。除去対象となる被処理水中の微粒子のサイズに応じた限外ろ過膜の分画分子量に基づくサイズを有するもの、例えば、限外ろ過膜のメインの孔のサイズ(孔径)以上のサイズから選択されたサイズを有する孔閉鎖用微粒子を選択して用いることができる。
また、この孔閉鎖用微粒子は、孔閉鎖用微粒子の限外ろ過膜への付加前後における、被処理水中の除去対象微粒子の除粒子率(排除率)を、実験によって確認することで決定することもできる。具体的には、先ず、限外ろ過膜の分画分子量を目安として、目的とする除粒子性能(被処理水から除去すべき微粒子の除去率)を得ることができる限外ろ過膜を選択し、被処理水を通水して選択された限外ろ過膜の除去すべき微粒子の除粒子率(R1)を求める。次に、限外ろ過膜に孔閉鎖用微粒子を付加した後、被処理水を通水して孔閉鎖用微粒子の付加後における限外ろ過膜の除粒子率(R2)を求める。このようにR1、R2を孔閉鎖用微粒子の種類やサイズで振り分けて実験を行い、R2>R1となる孔閉鎖用微粒子を選定する。
The size of the fine particles for closing the pores can be set according to the molecular weight cut-off of the ultrafiltration membrane and the particle removal performance targeted in the filtration treatment. A size based on the molecular weight cut off of the ultrafiltration membrane according to the size of the fine particles in the treated water to be removed, for example, a size larger than the size of the main pore (pore diameter) of the ultrafiltration membrane The pore closing fine particles having different sizes can be selected and used.
In addition, the pore closing fine particles should be determined by confirming experimentally the particle removal rate (exclusion rate) of the removal target fine particles in the treated water before and after the addition of the pore closing fine particles to the ultrafiltration membrane. You can also. Specifically, first, an ultrafiltration membrane that can achieve the desired particle removal performance (removal rate of fine particles to be removed from the water to be treated) is selected using the molecular weight cut off of the ultrafiltration membrane as a guide. Then, the removal rate (R1) of the fine particles to be removed of the selected ultrafiltration membrane is obtained by passing the water to be treated. Next, after adding pore-closing fine particles to the ultrafiltration membrane, the water to be treated is passed through to determine the particle removal rate (R2) of the ultrafiltration membrane after addition of the pore-closing fine particles. In this way, R1 and R2 are distributed according to the type and size of the pore closing fine particles, and the experiment is performed, and the pore closing fine particles satisfying R2> R1 are selected.

分画分子量が5000〜7000の限外ろ過膜を用いる場合における孔閉鎖用の微粒子のサイズは、5nm〜500nmの範囲から、孔閉鎖用の微粒子の付加後に目的とする微粒子サイズにおける排除率の向上を達成するサイズを選択することができる。この場合における孔閉鎖用の微粒子のサイズの下限は、10nmが好ましく、孔閉鎖用の微粒子のサイズの上限は、100nmが好ましく、50nmがより好ましく、30nmが更に好ましい。なお、ここで言う微粒子のサイズは平均粒径であり、粒径幅(CV)が15%以下のものを使用するのが好ましい。
限外ろ過膜への孔閉鎖用の微粒子の付加率は、膜面積に対して10%(面積比)以下に設定することが、除粒子性能を向上させつつ、ケーキろ過状態を形成せずに、通水における顕著な差圧上昇を抑制するために好ましい。孔閉鎖用の微粒子の付加率は、0.01%以上、好ましくは0.1%以上、更に好ましくは0.5%を超えた値に設定することができる。孔閉鎖用微粒子の膜面積に対する付加率は、微粒子がそのサイズを直径とする単一球形であり、単層で膜面に付着すると仮定したときの微粒子投影面積の総和の膜面積に対する割合である。
In the case of using an ultrafiltration membrane having a molecular weight cut off of 5000 to 7000, the size of fine particles for pore closure is in the range of 5 nm to 500 nm, and the removal rate is improved at the desired fine particle size after addition of fine particles for pore closure The size to achieve can be selected. In this case, the lower limit of the size of the fine particles for hole closing is preferably 10 nm, and the upper limit of the size of the fine particles for hole closing is preferably 100 nm, more preferably 50 nm, and still more preferably 30 nm. The size of the fine particles referred to here is an average particle size, and it is preferable to use those having a particle size width (CV) of 15% or less.
The addition rate of fine particles for pore closure to the ultrafiltration membrane is set to 10% (area ratio) or less with respect to the membrane area without improving the particle removal performance and without forming a cake filtration state. It is preferable for suppressing a significant increase in differential pressure in water flow. The addition rate of the fine particles for closing the pores can be set to a value exceeding 0.01%, preferably 0.1% or more, and more preferably exceeding 0.5%. The rate of addition of the pore closing fine particles to the membrane area is the ratio of the sum of the fine particle projected area to the membrane area when the fine particles are assumed to be a single sphere having a diameter as a diameter and adhere to the membrane surface as a single layer. .

微粒子付加率は、限外ろ過膜の膜面に付加された微粒子の数に基づいて以下の式(1)により算出することができる。
微粒子付加率=[微粒子付加量(個数)から得られる膜面上での微粒子の占有面積]/[限外ろ過膜の膜面の面積]×100%・・・・式(1)
微粒子付加量(個数)は、調製用水の微粒子濃度×調製用水の積算通水量(単位時間当たりの通水量×時間)から求めることができ、また、膜面での微粒子の占有面積は以下の式(2)により求めることができる。
微粒子付加量(個数)×各微粒子の膜面上への投影面積・・・式(2)
なお、各球形微粒子の投影面積Sは、S=π(L/2)2(L=球状微粒子の直径)である。
The fine particle addition rate can be calculated by the following equation (1) based on the number of fine particles added to the membrane surface of the ultrafiltration membrane.
Fine particle addition rate = [occupied area of fine particles on the membrane surface obtained from the added amount (number) of fine particles] / [area of the membrane surface of the ultrafiltration membrane] × 100% (1)
The amount of added fine particles (number) can be determined from the concentration of fine particles in the preparation water x the cumulative amount of preparation water (the amount of water flow per unit time x time). The area occupied by fine particles on the membrane surface is (2).
Amount of added fine particles (number) x projected area of each fine particle on the film surface (2)
The projected area S of each spherical fine particle is S = π (L / 2) 2 (L = diameter of spherical fine particle).

なお、孔閉鎖用微粒子のサイズよりも小さな微粒子が調製用水に含まれていても差し支えない。小さな微粒子は、限外ろ過膜を通過して排出される。処理後の限外ろ過膜の除粒子性能に影響を及ぼすことはない。しかし、限外ろ過膜からの処理水中に調製用水中に含まれていた微粒子が流出しないように、使用前に限外ろ過膜の膜中や二次側に付着した小さな微粒子を、洗浄やブロー処理により予め排出することが好ましい。一方、孔閉鎖用のサイズよりも大きな微粒子が調製用水に含まれていても、更に大きな孔を塞ぐことができるので差し支えない。   It should be noted that fine water particles smaller than the pore closing fine particles may be contained in the preparation water. Small particulates are discharged through the ultrafiltration membrane. It does not affect the particle removal performance of the ultrafiltration membrane after treatment. However, in order to prevent the fine particles contained in the preparation water from flowing into the treated water from the ultrafiltration membrane, small particles adhering to the membrane or the secondary side of the ultrafiltration membrane before use are washed or blown. It is preferable to discharge in advance by treatment. On the other hand, even if fine particles larger than the size for closing the hole are contained in the preparation water, the larger hole can be closed, so that there is no problem.

孔閉鎖用微粒子のサイズの特定には、微粒子を取扱う際に当業界において通常用いられているものを利用すればよく、球形であればその直径を用いることができる。   In order to specify the size of the fine particles for closing the pores, those usually used in the art when handling the fine particles may be used, and the diameter of the spherical fine particles can be used.

限外ろ過膜に孔閉鎖用微粒子を付加するための調製用水は、孔閉鎖用微粒子を水に分散させて調製することができる。調製用水を得るための水は、限外ろ過処理する水のグレードに応じて選択することができる。例えば、限外ろ過処理される水が純水や超純水であれば、調製用水を得るための水として純水や超純水を用いることが好ましい。調製用水中の孔閉鎖用微粒子の濃度は、目的とする膜面積に対する微粒子付加率を得ることができるように設定すればよい。例えば、102〜1015個/ml、好ましくは103〜1013個/mlの範囲から選択することができる。
孔閉鎖用微粒子を含む調製用水の限外ろ過膜への孔閉鎖効果を得るための積算通水量は、目的とする孔閉鎖効果を得ることができるように設定すればよく、上述した付加率が達成できるように、孔閉鎖用微粒子の調製用水中の濃度、通水時間、流速等に基づいて設定することが好ましい。
Preparation water for adding pore closing fine particles to an ultrafiltration membrane can be prepared by dispersing pore closing fine particles in water. The water for obtaining the water for preparation can be selected according to the grade of the water to be ultrafiltered. For example, if the ultrafiltered water is pure water or ultrapure water, it is preferable to use pure water or ultrapure water as water for obtaining the preparation water. The concentration of fine particles for closing pores in the preparation water may be set so as to obtain the addition rate of fine particles with respect to the target membrane area. For example, it can be selected from the range of 10 2 to 10 15 pieces / ml, preferably 10 3 to 10 13 pieces / ml.
The integrated water flow rate for obtaining the pore closing effect on the ultrafiltration membrane of the preparation water containing the pore closing fine particles may be set so as to obtain the target pore closing effect, and the above-mentioned addition rate is In order to achieve this, it is preferable to set the concentration based on the concentration of the fine particles for closing the pores in the preparation water, the water flow time, the flow rate, and the like.

孔閉鎖用微粒子の限外ろ過膜への付加処理による調製は、調製用装置中に限外ろ過膜を設置して、超純水製造装置の限外ろ過膜装置への設置前に予め行うことができる。   Preparation by adding pore closing microparticles to the ultrafiltration membrane should be performed in advance before installing the ultrafiltration membrane device in the ultrafiltration membrane device. Can do.

図1に調製用装置の一例を示す。図1の調製用装置は、限外ろ過膜モジュール1を脱着可能に設置する処理部4、調製用水の貯留槽2−1、貯留槽2−1から処理部4へ調製用水を供給する供給系2−2、処理部4からのろ液を回収系(不図示)に排出する排出系3を有する。供給系2−2は、配管と、配管の途中に配置された弁及びポンプを有する。供給系2−2と切り替え可能に供給系2−4が設けられおり、限外ろ過膜モジュール1への充填液の貯留槽2−3から充填液の供給が可能となっている。
図示した例では、限外ろ過膜モジュール1と供給系2−2とは栓1−1を介して、排出系3とは栓1−2を介して脱着可能に接続されており、調製用水での処理終了後に、栓1−1及び1−2を閉じて充填液を満たした状態で密閉した限外ろ過膜モジュール1を処理部4から取り出し可能となっている。
FIG. 1 shows an example of a preparation apparatus. The preparation apparatus in FIG. 1 includes a processing unit 4 in which the ultrafiltration membrane module 1 is detachably installed, a preparation water storage tank 2-1, and a supply system for supplying preparation water from the storage tank 2-1 to the processing unit 4. 2-2. A discharge system 3 for discharging the filtrate from the processing unit 4 to a recovery system (not shown). The supply system 2-2 includes a pipe and a valve and a pump arranged in the middle of the pipe. A supply system 2-4 is provided so as to be switchable with the supply system 2-2, and the filling liquid can be supplied from the filling liquid storage tank 2-3 to the ultrafiltration membrane module 1.
In the illustrated example, the ultrafiltration membrane module 1 and the supply system 2-2 are detachably connected to each other via the plug 1-1 and the discharge system 3 via the plug 1-2. After the process is completed, the ultrafiltration membrane module 1 sealed with the plugs 1-1 and 1-2 closed and filled with the filling liquid can be taken out from the processing unit 4.

処理部4に限外ろ過膜モジュール1を設置して、供給系2−2及び排出系3と接続させ、栓1−1、1−2を開け、貯留槽2−1から供給系2−2を経て、調製用水を限外ろ過膜モジュール1の一次側1Aへ供給する。二次側1Bからのろ液は排出系3を介して排出される。限外ろ過膜の一次側膜面において目的とする微粒子付加量が得られた時点で調製用水の限外ろ過膜の一次側への供給を停止する。供給系2−2を供給系2−4に切り替え、貯留槽2−3から充填液を限外ろ過膜モジュールに通液する。限外ろ過膜モジュール1内の調製用水を充填液に置き換えた状態で栓1−1及び1−2を閉じて密閉し、処理済み限外ろ過膜モジュールとして、超純水製造装置のサブシステムにおける微粒子除去に用いることができる。   The ultrafiltration membrane module 1 is installed in the processing unit 4 and connected to the supply system 2-2 and the discharge system 3, the plugs 1-1 and 1-2 are opened, and the supply system 2-2 from the storage tank 2-1 is opened. Then, water for preparation is supplied to the primary side 1A of the ultrafiltration membrane module 1. The filtrate from the secondary side 1B is discharged through the discharge system 3. When the target addition amount of fine particles is obtained on the primary membrane surface of the ultrafiltration membrane, the supply of preparation water to the primary side of the ultrafiltration membrane is stopped. The supply system 2-2 is switched to the supply system 2-4, and the filling liquid is passed from the storage tank 2-3 to the ultrafiltration membrane module. In the state where the preparation water in the ultrafiltration membrane module 1 is replaced with the filling liquid, the plugs 1-1 and 1-2 are closed and sealed, and as a processed ultrafiltration membrane module, in the subsystem of the ultrapure water production apparatus It can be used for fine particle removal.

充填液は、膜の乾燥を防止するためのものであり、純水やホルマリン(ホルムアミド水溶液)等の薬液を用いることができる。ホルマリン等の薬液は、処理済みの限外ろ過膜モジュールの長期保存用として利用することができ、ホルマリンのホルムアミド濃度としては数千ppm程度とすることができる。充填液として純水を用い、限外ろ過膜モジュールに通水して、二次側1Bに透過した小さい粒子を限外ろ過膜モジュールから排除する洗浄処理を行ってもよい。   The filling liquid is for preventing the film from drying, and a chemical solution such as pure water or formalin (formamide aqueous solution) can be used. A chemical solution such as formalin can be used for long-term storage of a treated ultrafiltration membrane module, and the formamide concentration of formalin can be about several thousand ppm. You may perform the washing process which uses pure water as a filling liquid, passes water through the ultrafiltration membrane module, and excludes small particles permeated to the secondary side 1B from the ultrafiltration membrane module.

限外ろ過膜モジュールは、限外ろ過膜を密封可能な容器に収納し、限外ろ過膜装置に着脱可能に設置できる構造を有するカートリッジタイプとすることができる。このカートリッジタイプの限外ろ過膜モジュールに、上述したような調製用装置での調製用水での処理と、充填液の充填及び密封を行い、保管、輸送等を経て超純水製造装置の限外ろ過膜装置に設置して使用することができる。また、膜モジュールは中空糸型の他、チューブラー型、スパイラル型、モノリス型等、種々の膜モジュールを使用することができる。
図1に示す装置における調製用水での処理は、全ろ過処理であるが、限外ろ過膜モジュールを濃縮水取り出し可能な構成とし、限外ろ過膜に対してクロスフローで調製用水を供給して、濃縮水を取り出すろ過条件を採用してもよい。調製用水の濃縮水は、循環系を用いて貯留槽に戻して再利用することもできる。この点は、後述する図2で示す限外ろ過膜装置内での処理においても同様である。
An ultrafiltration membrane module can be made into the cartridge type which has a structure which accommodates an ultrafiltration membrane in the container which can be sealed, and can be installed in an ultrafiltration membrane apparatus so that attachment or detachment is possible. This cartridge-type ultrafiltration membrane module is treated with water for preparation in the preparation apparatus as described above, filled with a filling liquid and sealed, stored, transported, etc. It can be installed and used in a filtration membrane device. In addition to the hollow fiber type, various membrane modules such as a tubular type, a spiral type, and a monolith type can be used as the membrane module.
The treatment with the preparation water in the apparatus shown in FIG. 1 is a total filtration treatment, but the ultrafiltration membrane module is configured so that concentrated water can be taken out, and the preparation water is supplied to the ultrafiltration membrane by crossflow. Filtration conditions for removing concentrated water may be employed . The concentrated water of the preparation water can be returned to the storage tank using a circulation system and reused. This also applies to the processing in the ultrafiltration membrane device shown in FIG.

本発明にかかる調製方法により微粒子が付加された限外ろ過膜を用いた限外ろ過膜は、例えば、特許文献1に開示されるような超純水製造装置のサブシステムの末端又はその近傍に設けられた限外ろ過膜装置に好適に用いることができる。   The ultrafiltration membrane using the ultrafiltration membrane added with fine particles by the preparation method according to the present invention is, for example, at the end of the subsystem of the ultrapure water production apparatus as disclosed in Patent Document 1 or in the vicinity thereof. It can use suitably for the provided ultrafiltration membrane apparatus.

本発明にかかる被処理水の水処理方法は、限外ろ過膜に、微粒子を含む調製用水を通水して該限外ろ過膜に該微粒子を付加する調製工程と、前記調製工程を行った後、前記限外ろ過膜に被処理水を通水する工程と、
を含む。
上記の調製工程は、限外ろ過膜に微粒子を含む調製用水を通水させる第1の装置に限外ろ過膜を装着して、第1の装置に装着した限外ろ過膜に前記調製用水を通水させる工程とすることができる。この第1の装置としては、図1に示す調製装置を用いることができる。
上記の限外ろ過膜に被処理水を通水する工程は、調製工程により第1の装置に装着された限外ろ過膜に調製用水を通水させた後、第1の装置に装着された限外ろ過膜を前記第1の装置から取り外し、第1の装置から取り外した限外ろ過膜を、被処理水から超純水を製造するための第2の装置に装着して、第2の装置に装着された前記限外ろ過膜に被処理水を通水する工程とすることができる。
In the water treatment method for water to be treated according to the present invention, a preparation step of passing water for preparation containing fine particles through an ultrafiltration membrane and adding the fine particles to the ultrafiltration membrane was performed. Thereafter, a process of passing the treated water through the ultrafiltration membrane,
including.
In the above preparation step, the ultrafiltration membrane is attached to the first device that allows the preparation water containing fine particles to flow through the ultrafiltration membrane, and the preparation water is applied to the ultrafiltration membrane attached to the first device. It can be set as the process of making water flow. As this first apparatus, the preparation apparatus shown in FIG. 1 can be used.
The process of passing the water to be treated through the ultrafiltration membrane is performed by passing the preparation water through the ultrafiltration membrane attached to the first device by the preparation step, and then attaching to the first device. The ultrafiltration membrane is removed from the first device, and the ultrafiltration membrane removed from the first device is attached to a second device for producing ultrapure water from the treated water, It can be set as the process of passing water to be treated through the ultrafiltration membrane attached to the apparatus.

孔閉鎖用微粒子の限外ろ過膜への付加処理による調製は、図2の一実施形態に示すとおり、超純水製造装置の限外ろ過膜装置の前段に調製用装置を付加した形態で行うこともできる。図示した限外ろ過膜装置は、限外ろ過膜モジュール1、被処理水の供給系6、被処理水の貯留槽5、調製用水の貯留槽2、処理された水をユースポイントへ供給するための排出系3A、濃縮水取り出し系3Bを有する。被処理水の限外ろ過膜モジュール1での処理を行う本運転に先だって、切り替えバブルを調節して限外ろ過膜モジュール1と調製用水の供給系とを接続し、濃縮水取り出し系3Bを閉鎖した状態で、貯留槽2の調製用水を限外ろ過膜モジュール1の一次側に供給し、限外ろ過膜への通水を行う。限外ろ過膜に通水した調製用水は、限外ろ過膜装置の二次側に設けた排出系から分岐されたブロー(不図示)から排出される。調製用水中に含まれる微粒子の目的とする付加量が限外ろ過膜の膜面に得られた段階で、調製用水の通水を停止して、調製処理を終了する。調製用水の供給系を、被処理水供給系に切り替え、貯留槽5から被処理水を限外ろ過膜モジュール1に導入して除粒子処理を行う。
なお、調製用水の供給系から被処理水供給系への切り替え時後の所定時間を洗浄処理に利用して、限外ろ過膜モジュール1の二次側に小さな微粒子が透過して存在する場合は、これを洗浄処理によって除去し、別途設けた排出系(不図示)により廃棄してもよい。あるいは、洗浄用の水、例えば超純水を限外ろ過膜モジュール1の一次側に供給するための洗浄水供給系(不図示)を別途設置し、調製用水の供給系から被処理水供給系への切り替え時に、洗浄を行ってから被処理水供給系への切り替えを行ってもよい。
図2における限外ろ過膜装置での本運転において、濃縮水を取り出す場合には濃縮水取り出し系3Bが利用され、全ろ過運転を行う場合には濃縮水取り出し系3Bを閉じればよい。
The preparation by adding the pore closing fine particles to the ultrafiltration membrane is performed in a form in which a preparation device is added to the front stage of the ultrafiltration membrane device of the ultrapure water production apparatus as shown in one embodiment of FIG. You can also. The illustrated ultrafiltration membrane device is for supplying ultrafiltration membrane module 1, treated water supply system 6, treated water storage tank 5, preparation water storage tank 2, treated water to a use point. A discharge system 3A and a concentrated water discharge system 3B. Prior to the main operation in which the water to be treated is treated with the ultrafiltration membrane module 1, the switching bubble is adjusted to connect the ultrafiltration membrane module 1 with the water supply system for preparation, and the concentrated water removal system 3B is closed. In this state, water for preparation of the storage tank 2 is supplied to the primary side of the ultrafiltration membrane module 1 and water is passed through the ultrafiltration membrane. The preparation water passed through the ultrafiltration membrane is discharged from a blow (not shown) branched from a discharge system provided on the secondary side of the ultrafiltration membrane device. At the stage where the desired addition amount of the fine particles contained in the preparation water is obtained on the membrane surface of the ultrafiltration membrane, the preparation water is stopped and the preparation process is terminated. The preparation water supply system is switched to the treated water supply system, and the treated water is introduced from the storage tank 5 into the ultrafiltration membrane module 1 to perform the particle removal treatment.
In the case where a small amount of fine particles permeate on the secondary side of the ultrafiltration membrane module 1 by using the predetermined time after the switching from the preparation water supply system to the treated water supply system for the cleaning process. This may be removed by a cleaning process and discarded by a separate discharge system (not shown). Alternatively, a cleaning water supply system (not shown) for supplying cleaning water, for example, ultrapure water, to the primary side of the ultrafiltration membrane module 1 is separately installed, and the water to be treated is supplied from the preparation water supply system. At the time of switching to, it may be switched to the treated water supply system after washing.
In the main operation with the ultrafiltration membrane device in FIG. 2, the concentrated water extraction system 3B is used when extracting concentrated water, and the concentrated water extraction system 3B may be closed when performing the total filtration operation.

調製対象の限外ろ過膜は、特に限定されるものではなく、上水、工業用水、純水、超純水等の被処理水の種類やろ過目的に応じて選択することができる。特に、超純水システムの末端又はその近傍に設置する限外ろ過膜装置に対して適用することが好ましい。このような限外ろ過膜として、例えば、旭化成ケミカルズ製(OLT-6036H)、日東電工製(NTU-3306-K6R)を、プラント用限外ろ過膜モジュールとして挙げることができる。いずれも分画分子量6000のポリスルホン製中空糸膜モジュールである。
本発明にかかる調製方法により微粒子が付加された限外ろ過膜を用いた限外ろ過膜は、例えば、特許文献1に開示されるような超純水製造装置のサブシステムの末端又はその近傍に設けられた限外ろ過膜装置に好適に用いることができる。
The ultrafiltration membrane to be prepared is not particularly limited, and can be selected according to the type of water to be treated such as clean water, industrial water, pure water, and ultrapure water and the purpose of filtration. In particular, the present invention is preferably applied to an ultrafiltration membrane device installed at or near the end of an ultrapure water system. As such ultrafiltration membranes, for example, Asahi Kasei Chemicals (OLT-6036H) and Nitto Denko (NTU-3306-K6R) can be cited as plant ultrafiltration membrane modules. Both are polysulfone hollow fiber membrane modules having a molecular weight cut off of 6000.
The ultrafiltration membrane using the ultrafiltration membrane added with fine particles by the preparation method according to the present invention is, for example, at the end of the subsystem of the ultrapure water production apparatus as disclosed in Patent Document 1 or in the vicinity thereof. It can use suitably for the provided ultrafiltration membrane apparatus.

図3に、本発明の限外ろ過膜装置を組み込んだ超純水製造装置の一実施形態のフロー図を示す。図3に示す装置は、一次純水システム41とその下流側に接続された二次純水システム42(サブシステム)を有する。
二次純水システム42は、一次純水を貯留する純水貯槽43の下流側に、紫外線酸化装置44(図中UVで示す)、強酸性陽イオン交換樹脂と強塩基性陰イオン交換樹脂との混床による1塔式の非再生型イオン交換装置45(図中CPで示す)、膜脱気装置46(図中MDで示す)、限外ろ過膜装置47(図中UFで示す)を、この順序に通水するように設置したものである。限外ろ過膜装置47として、本発明の限外ろ過膜装置が組み込まれている。限外ろ過膜装置47からの超純水は、ユースポイント48に供給される。二次純水システム42では連続循環運転を行っており、得られた超純水の一部をユースポイント48に送るとともに、残部を純水貯槽43に循環している。なお、紫外線酸化装置44とその後段の非再生型イオン交換装置45との間、非再生型イオン交換装置45とその後段の膜脱気装置46との間、膜脱気装置46とその後段の限外ろ過膜装置47との間には、必要に応じ、他の装置を設置してもよい。
FIG. 3 shows a flow diagram of an embodiment of an ultrapure water production apparatus incorporating the ultrafiltration membrane device of the present invention. The apparatus shown in FIG. 3 has a primary pure water system 41 and a secondary pure water system 42 (subsystem) connected to the downstream side thereof.
The secondary pure water system 42 includes an ultraviolet oxidation device 44 (indicated by UV in the figure), a strongly acidic cation exchange resin, a strongly basic anion exchange resin, and a downstream side of a pure water storage tank 43 that stores primary pure water. 1-column non-regenerative ion exchanger 45 (indicated by CP in the figure), membrane deaerator 46 (indicated by MD in the figure), and ultrafiltration membrane apparatus 47 (indicated by UF in the figure) The water is installed in this order. As the ultrafiltration membrane device 47, the ultrafiltration membrane device of the present invention is incorporated. The ultrapure water from the ultrafiltration membrane device 47 is supplied to the use point 48. In the secondary pure water system 42, continuous circulation operation is performed, and a part of the obtained ultrapure water is sent to the use point 48 and the remaining part is circulated to the pure water storage tank 43. It should be noted that the ultraviolet oxidizer 44 and the subsequent non-regenerative ion exchanger 45, the non-regenerative ion exchanger 45 and the subsequent membrane deaerator 46, and the membrane deaerator 46 and the downstream You may install another apparatus between the ultrafiltration membrane apparatus 47 as needed.

また、一次純水システム41としては、目的とする一次純水が得られる構成とすればよく、例えば、前処理システムによって懸濁物質、有機物の一部等が除去された水が導入され、その水の中のイオン、非イオン性物質、溶存ガス等の大部分を除去して一次純水を得るシステムを利用することができる。
本発明にかかる調製方法によって得られる限外ろ過膜における除粒子性能の確認は、微粒子のサイズによって、パーティクルカウンターや、特許文献2及び3に開示の直接測定方法等によって行うことができる。
本発明に調製方法によれば、従来のろ過実績のある限外ろ過膜を用いた場合でも、高性能化及び高信頼化を達成することができる。また、市販の限外ろ過に簡便な方法で調製処理を行うことができるので、限外ろ過膜の設置及び交換にかかるコストを低く抑えることができる。
The primary pure water system 41 may be configured to obtain the intended primary pure water. For example, water from which suspended substances, part of organic substances, and the like have been removed by the pretreatment system is introduced, It is possible to use a system that obtains primary pure water by removing most of ions, nonionic substances, dissolved gases, etc. in the water.
Confirmation of the particle removal performance in the ultrafiltration membrane obtained by the preparation method according to the present invention can be performed by a particle counter, a direct measurement method disclosed in Patent Documents 2 and 3, or the like depending on the size of the fine particles.
According to the preparation method of the present invention, high performance and high reliability can be achieved even when an ultrafiltration membrane with a conventional filtration record is used. Moreover, since a preparation process can be performed by a simple method for commercially available ultrafiltration, the cost concerning installation and replacement | exchange of an ultrafiltration membrane can be held down low.

本発明の調製方法によれば、限外ろ過膜に孔閉鎖用の微粒子が付加されていることで、限外ろ過膜の完全性を向上させ、除粒子率を高めることができる。特に、超純水中のsub-50nm微粒子除去に効果を発揮する限外ろ過膜の提供が可能となる。
なお、微粒子を含む超純水を被処理水とする限外ろ過処理において、被処理水の限外ろ過膜への通水開始からある程度の時間経過後に被処理水中に孔閉鎖作用を有する微粒子が含まれている場合には、本発明に係る除粒子性能の向上効果が期待できる。しかし、大きな孔が塞がるまでの時間内ではろ過性能は向上しておらず、しかも、超純水中の微粒子の種類、並びにそのサイズ及び個数に関する分布は超純水の種類やその製造方法等によって変動し、また、限外ろ過膜の種類もろ過目的に応じて設定されるため、大きな孔を塞ぐことによる効果が得られるまの通水時間は通水処理毎に異なる。しかも、工業的に利用される限外ろ過膜の膜面積は非常に大きく、かかる除粒子性能が向上していない状態での通水時間も長くなる。
これに対して、本発明では、予め設定された条件での孔閉鎖用微粒子の限外ろ過膜への付加を確実に行うことで、除粒子性能の向上を再現性よく得ており、通常の微粒子を含む超純水の限外ろ過処理と大きく異なるものである。
According to the preparation method of the present invention, the pore-closing fine particles are added to the ultrafiltration membrane, whereby the integrity of the ultrafiltration membrane can be improved and the particle removal rate can be increased. In particular, it is possible to provide an ultrafiltration membrane that is effective in removing sub-50 nm fine particles from ultrapure water.
In ultrafiltration treatment using ultrapure water containing fine particles as treated water, fine particles having a pore closing action in treated water after a certain amount of time has elapsed since the start of water flow to the ultrafiltration membrane of treated water. When it is contained, the effect of improving the particle removal performance according to the present invention can be expected. However, the filtration performance has not improved within the time until the large pores are blocked, and the type of fine particles in ultrapure water, and the size and number distribution depends on the type of ultrapure water and the method of production thereof. In addition, since the type of the ultrafiltration membrane is also set according to the purpose of filtration, the water passage time until the effect of blocking the large hole is obtained is different for each water passage treatment. And the membrane area of the ultrafiltration membrane utilized industrially is very large, and the water passage time in the state which this particle removal performance is not improved also becomes long.
On the other hand, in the present invention, the improvement of the particle removal performance is obtained with good reproducibility by reliably adding the pore closing fine particles to the ultrafiltration membrane under preset conditions. This is very different from the ultrafiltration treatment of ultrapure water containing fine particles.

実施例1
分画分子量6000のポリスルホン製中空糸型限外ろ過膜モジュールの中空糸膜をセットした小型モジュールを作製し、中空糸膜の一次側(外側)から超純水中に粒径10nmと規定された金粒子(金コロイド)試薬(平均粒径10nm、粒径幅(CV)10%未満)を添加、分散させた調製用水を通水し、金粒子の付加率に対する被処理水の微粒子除去率を測定した。調製用水に含まれる金濃度は約1ppbとした。なお、通水はデッドエンド式の全ろ過条件で行った。各時点での積算通水量によって膜面積に対する金粒子の付加率を先に示した式(1)及び(2)により算出した。
限外ろ過膜からの透過液(中空糸膜の内側に透過してくる水)を採取して、透過液中の金濃度をICP-MS分析法により測定した。限外ろ過膜の入口と出口の金濃度から、限外ろ過膜の金粒子の除粒子率(排除率)を求めた(特許文献4参照)。
表1に、金粒子の粒子付加率と、金粒子の除粒子率との関係を示す。金粒子を限外ろ過膜に付加する(粒子付加率が大きくなる)につれて、除粒子率が大きくなった。分画分子量6000の限外ろ過膜は、10nmの粒子を十分に排除することができる(排除率90%以上)。すなわちメインの孔径は10nmよりも小さい。しかし、僅かに金粒子が限外ろ過の二次側にリークするということは、限外ろ過膜には孔径分布があり10nm粒子が通ることができる細孔が少なくとも存在していることを示す(不完全性)。本実施例によって、10nm粒子(金粒子)を限外ろ過膜に付加することで、10nm粒子が通ることができる細孔が閉塞され(粒子付加率が大きくなれば、閉塞される細孔が多くなる)、除粒子率が大きくなることが確認された。金粒子(金コロイド)試薬には粒度分布があり、10nmと規定されていても、10nmよりも大きな粒子が存在する。この大きな粒子は、限外ろ過膜にある10nm粒子が通ることができる細孔を閉塞することができる。また、10nm粒子でも10nm粒子が通ることができる細孔内で捕捉されることもあり、10nm粒子が通ることができる細孔を閉塞することができる。これにより限外ろ過膜に粒子を付加することで、限外ろ過膜の除粒子性能(微粒子の除粒子率)が向上することが確認された。なお、このとき明らかなフラックスの低下は認められなかった。
Example 1
A small module in which a hollow fiber membrane of a polysulfone hollow fiber ultrafiltration membrane module with a molecular weight cut off of 6000 was set was prepared, and the particle size was defined as 10 nm in ultrapure water from the primary side (outside) of the hollow fiber membrane. The preparation water to which gold particle (gold colloid) reagent (average particle size 10 nm, particle size width (CV) less than 10%) is added and dispersed is passed, and the removal rate of treated water with respect to the addition rate of gold particles It was measured. The gold concentration contained in the preparation water was about 1 ppb. The water flow was performed under dead-end total filtration conditions. The addition rate of the gold particles with respect to the membrane area was calculated by the formulas (1) and (2) shown above based on the accumulated water flow at each time point.
The permeate from the ultrafiltration membrane (water permeating inside the hollow fiber membrane) was collected, and the gold concentration in the permeate was measured by ICP-MS analysis. From the gold concentrations at the inlet and outlet of the ultrafiltration membrane, the particle removal rate (exclusion rate) of gold particles in the ultrafiltration membrane was determined (see Patent Document 4).
Table 1 shows the relationship between the particle addition rate of gold particles and the particle removal rate of gold particles. As gold particles were added to the ultrafiltration membrane (particle addition rate increased), the particle removal rate increased. An ultrafiltration membrane with a molecular weight cut off of 6000 can sufficiently exclude particles of 10 nm (exclusion rate of 90% or more). That is, the main hole diameter is smaller than 10 nm. However, the slight leakage of gold particles to the secondary side of the ultrafiltration indicates that the ultrafiltration membrane has at least pores that have a pore size distribution and allow 10 nm particles to pass through ( Imperfection). According to this example, by adding 10 nm particles (gold particles) to the ultrafiltration membrane, the pores through which the 10 nm particles can pass are blocked (if the particle addition rate increases, the number of blocked pores increases. It was confirmed that the particle removal rate was increased. Gold particle (gold colloid) reagent has a particle size distribution, and even if it is defined as 10 nm, particles larger than 10 nm exist. These large particles can block the pores through which 10 nm particles in the ultrafiltration membrane can pass. Further, even 10 nm particles may be trapped in the pores through which 10 nm particles can pass, and the pores through which 10 nm particles can pass can be blocked. Thereby, it was confirmed that the particle removal performance (particle removal rate of fine particles) of the ultrafiltration membrane is improved by adding particles to the ultrafiltration membrane. At this time, no apparent decrease in flux was observed.

Figure 0006433737
Figure 0006433737

1 限外ろ過膜モジュール1
1−1、1−2 栓
2−1 調製用水の貯留槽
2−2 調製用水の供給系
2−3 充填液の貯留槽
2−4 充填液の供給系
3 排出系
4 処理部
1 Ultrafiltration membrane module 1
1-1, 1-2 Plug 2-1 Preparation water storage tank 2-2 Preparation water supply system 2-3 Filling liquid storage tank 2-4 Filling liquid supply system 3 Discharge system 4 Processing section

Claims (2)

超純水中の微粒子を除去するポリスルホン製の限外ろ過膜に、微粒子を含む調製用水を通水して該限外ろ過膜に該微粒子を付加する処理を行う限外ろ過膜の調製方法であって、
前記調製用水に含まれる微粒子のサイズが、5nmから500nmの範囲から選択され、
前記調製用水に含まれる微粒子の前記限外ろ過膜への付加量が、前記限外ろ過の膜面積に対して10%以下である
ことを特徴とする限外ろ過膜の調製方法。
A method for preparing an ultrafiltration membrane in which ultrafine membranes made of polysulfone that removes microparticles in ultrapure water are subjected to a treatment in which water for preparation containing microparticles is passed and the microparticles are added to the ultrafiltration membrane. There,
The size of the fine particles contained in the preparation water is selected from the range of 5 nm to 500 nm ;
The method for preparing an ultrafiltration membrane, wherein the amount of fine particles contained in the preparation water added to the ultrafiltration membrane is 10% or less with respect to the membrane area of the ultrafiltration. .
前記調製用水に含まれる微粒子が金粒子、ポリスチレンラテックス粒子、シリカ粒子の少なくともいずれかである請求項に記載の限外ろ過膜の調製方法。 The method for preparing an ultrafiltration membrane according to claim 1 , wherein the fine particles contained in the preparation water are at least one of gold particles, polystyrene latex particles, and silica particles.
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