JP3489148B2 - Method for removing impurities from polymer ion exchange membrane - Google Patents
Method for removing impurities from polymer ion exchange membraneInfo
- Publication number
- JP3489148B2 JP3489148B2 JP24365593A JP24365593A JP3489148B2 JP 3489148 B2 JP3489148 B2 JP 3489148B2 JP 24365593 A JP24365593 A JP 24365593A JP 24365593 A JP24365593 A JP 24365593A JP 3489148 B2 JP3489148 B2 JP 3489148B2
- Authority
- JP
- Japan
- Prior art keywords
- exchange membrane
- ion exchange
- aqueous solution
- temperature
- polymer ion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Description
【０００１】[0001]
【産業上の利用分野】本発明は、高分子イオン交換膜の
不純物除去方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing impurities from a polymer ion exchange membrane.
【０００２】[0002]
【従来の技術】高分子イオン交換膜は陽イオンまたは陰
イオンのいずれかのイオンを選択的に透過させるという
性質を有することから、電気透析にあっては陽陰の高分
子イオン交換膜が用いられている。また、陽イオンの高
分子イオン交換膜にあっては、水素と酸素の化学反応を
利用した燃料電池における電解質として採用されるに到
っている。ところで、高分子イオン交換膜を電気透析や
燃料電池に使用する際には、その性質を損なわないよう
或いは向上させるべく、種々の処理が行なわれている。
具体的に説明すると、次のような処理が行なわれてい
る。2. Description of the Related Art Since a polymer ion exchange membrane has a property of selectively permeating either cations or anions, a cation-anion polymer ion exchange membrane is used in electrodialysis. Has been. Further, a polymer ion exchange membrane for cations has been adopted as an electrolyte in a fuel cell utilizing a chemical reaction of hydrogen and oxygen. By the way, when the polymer ion-exchange membrane is used in electrodialysis or a fuel cell, various treatments are performed so as not to impair or improve its properties.
More specifically, the following processing is performed.
【０００３】陽イオンの高分子イオン交換膜（以下、単
に陽イオン交換膜という）のイオン交換基は負の極性を
有する。このため、このイオン交換基には正の電荷を持
つ不純物（金属イオン）がファンデルワールス力により
電気的に引き寄せられて結合している。従って、不純物
と結合したままでは、イオン交換基のイオン交換容量が
低下して膜自体のイオン導電率の低下を招く。この結
果、陽イオン交換膜を燃料電池における電解質として用
いた場合には、燃料電池としての出力密度が低下する。
よって、この不純物を除去するために、陽イオン交換膜
を沸騰水中に浸漬したり酸性水溶液中で沸騰処理するこ
とが行なわれている（DENKI KAGAKU，53，NO.10，812，
1985； The Journal of Chemistry，Vol.95，No.15，19
91)。つまり、陽イオン交換膜を沸騰処理することで、
イオン交換基と不純物との結合を熱エネルギーで解いて
不純物を除去し、イオン交換基のイオン交換容量および
膜のイオン導電率（膜のイオン交換機能）の維持が図ら
れている。The ion-exchange group of a cation polymer ion-exchange membrane (hereinafter, simply referred to as a cation-exchange membrane) has a negative polarity. Therefore, impurities (metal ions) having a positive charge are electrically attracted and bound to the ion exchange group by Van der Waals force. Therefore, if it remains bound to the impurities, the ion-exchange capacity of the ion-exchange group is reduced and the ionic conductivity of the membrane itself is reduced. As a result, when the cation exchange membrane is used as an electrolyte in a fuel cell, the output density of the fuel cell decreases.
Therefore, in order to remove the impurities, the cation exchange membrane is immersed in boiling water or subjected to boiling treatment in an acidic aqueous solution (DENKI KAGAKU, 53, NO.10, 812,
1985; The Journal of Chemistry, Vol.95, No.15, 19
91). In other words, by boiling the cation exchange membrane,
The bond between the ion exchange group and the impurity is released by thermal energy to remove the impurity, and the ion exchange capacity of the ion exchange group and the ionic conductivity of the membrane (ion exchange function of the membrane) are maintained.
【０００４】なお、燃料電池にあっては、陽イオン交換
膜中を水素イオンがＨ+（xＨ2Ｏ）の形で移動（透過）
するので、その抵抗は膜中水分および膜厚に依存するこ
とがよく知られている。従って、燃料電池の燃料ガス
（水素ガス）を加湿して供給して膜中水分を管理するこ
とと、膜厚をできるだけ薄くすることが行なわれてい
る。例えば、パーフルオロカーボンスルフォン酸ポリマ
ー膜（商品名：ナフィオン１１７， Du Pont社製）で
は、膜厚が約０．１８ｍｍ（乾燥時）である。In a fuel cell, hydrogen ions move (permeate) in the cation exchange membrane in the form of H + ( x H 2 O).
Therefore, it is well known that the resistance depends on the water content in the film and the film thickness. Therefore, the fuel gas (hydrogen gas) of the fuel cell is humidified and supplied to control the water content in the film, and the film thickness is made as thin as possible. For example, a perfluorocarbon sulfonic acid polymer film (trade name: Nafion 117, manufactured by Du Pont) has a film thickness of about 0.18 mm (when dried).
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記し
たように膜を沸騰処理する従来の不純物除去方法では、
不純物を除去できるものの、次のような問題点が指摘さ
れている。沸騰処理中には水中の空気が気化して生じた
無数の泡が、沸点下（１００℃の温度下）で陽イオン交
換膜表面に頻繁に衝突する。このため、陽イオン交換膜
に塑性変形が起こり、処理前にはしわや凹凸がなかった
膜がしわや凹凸が残存したままの膜となる。しかも、上
記したように膜が薄いので、しわや凹凸が顕著なまま残
存するとともに、膜厚が不均一となる。よって、沸騰処
理後の陽イオン交換膜の表裏面にガス拡散電極をホット
プレスする際にプレス不良、具体的にはガス拡散電極へ
の密着不良や密着力の低下が起き、陽イオン交換膜をガ
ス拡散電極で挟持した挟持体の内部抵抗の増大を招いて
いた。そして、この内部抵抗の増大により燃料電池の特
性を悪化させていた。なお、この内部抵抗の増大は、陽
イオン交換膜単体のものではないものの、イオン交換機
能の低下にほかならない。However, in the conventional method of removing impurities by boiling the film as described above,
Although impurities can be removed, the following problems have been pointed out. Countless bubbles generated by vaporization of air in water during the boiling treatment frequently collide with the surface of the cation exchange membrane at the boiling point (at a temperature of 100 ° C.). For this reason, the cation exchange membrane undergoes plastic deformation, and the membrane having no wrinkles or irregularities before the treatment becomes a membrane in which wrinkles or irregularities remain. In addition, since the film is thin as described above, wrinkles and unevenness remain remarkable, and the film thickness becomes uneven. Therefore, when hot pressing the gas diffusion electrode on the front and back surfaces of the cation exchange membrane after the boiling treatment, a press defect, specifically, a poor adhesion to the gas diffusion electrode or a decrease in adhesion force occurs, and the cation exchange film is not removed. This has led to an increase in the internal resistance of the sandwiched body sandwiched by the gas diffusion electrodes. The increase in the internal resistance deteriorates the characteristics of the fuel cell. It should be noted that this increase in internal resistance is nothing but the deterioration of the ion exchange function, although it is not for the cation exchange membrane alone.
【０００６】この場合、沸点が陽イオン交換膜のガラス
転移点温度より高いとガラス転移点温度を越える温度で
陽イオン交換膜を加熱処理してしまうため、塑性変形の
度合いが顕著となる。よって、上記した不具合も顕著に
起きると予想される。In this case, if the boiling point is higher than the glass transition temperature of the cation exchange membrane, the cation exchange membrane is heat-treated at a temperature exceeding the glass transition temperature, so that the degree of plastic deformation becomes remarkable. Therefore, it is expected that the above-mentioned problems will occur remarkably.
【０００７】また、塑性変形することにより膜がダメー
ジを受け局部的に膜が薄くなってしまい、膜全体として
のガス透過が必要以上に促進されてしまう。つまり、陽
イオン交換膜に加湿水素ガスを供給した場合に、水素が
ガス状のまま過剰に透過してしまうため燃料電池として
の特性を低下させていた。Further, the plastic deformation causes the film to be damaged, and the film is locally thinned, so that the gas permeation of the entire film is accelerated more than necessary. That is, when humidified hydrogen gas is supplied to the cation exchange membrane, hydrogen permeates excessively in a gaseous state, which deteriorates the characteristics of the fuel cell.
【０００８】本発明は、上記問題点を解決するためにな
され、高分子イオン交換膜を塑性変形させることなく不
純物を除去して膜のイオン交換機能の維持を図ることを
目的とする。The present invention has been made to solve the above problems, and an object thereof is to remove impurities without plastically deforming a polymer ion-exchange membrane to maintain the ion-exchange function of the membrane.
【０００９】[0009]
【課題を解決するための手段】かかる目的を達成するた
めになされた請求項１記載の発明は、陽イオンまたは陰
イオンに対するイオン交換基を備え陽陰いずれかのイオ
ンを選択的に透過する高分子イオン交換膜の不純物除去
方法であって、前記高分子イオン交換膜を水溶液中で加
熱処理する工程を含み、該工程における加熱処理温度を
前記水溶液の沸点又は前記高分子イオン交換膜のガラス
転移点温度のいずれか低い方の温度を下回る温度とした
ことをその要旨とする。In order to achieve the above object, the invention according to claim 1 is provided with an ion-exchange group for a cation or an anion and has a high permeability for selectively permeating either anion or cation. A method for removing impurities from a molecular ion exchange membrane, comprising the step of heat treating the polymer ion exchange membrane in an aqueous solution, wherein the heat treatment temperature in the step is the boiling point of the aqueous solution or the glass transition of the polymer ion exchange membrane. The gist is that the temperature is lower than the lower one of the point temperatures.
【００１０】[0010]
【作用】上記構成を有する高分子イオン交換膜の不純物
除去方法では、高分子イオン交換膜を加熱処理する際の
熱エネルギーにより、イオン交換基と金属イオン等の不
純物との結合を解いて不純物の除去を可能とする。しか
も、加熱処理温度を水溶液の沸点又は高分子イオン交換
膜のガラス転移点温度のいずれか低い方の温度を下回る
温度としたので、水溶液を沸騰させることはなく気泡と
高分子イオン交換膜との衝突を引き起こさないととも
に、高分子イオン交換膜をそのガラス転移点温度以上の
温度で加熱処理することはない。In the method for removing impurities from the polymer ion-exchange membrane having the above structure, the bond between the ion-exchange group and impurities such as metal ions is released by the thermal energy when the polymer ion-exchange membrane is heat-treated. Allows removal. Moreover, since the heat treatment temperature is set to a temperature lower than the lower temperature of the boiling point of the aqueous solution and the glass transition temperature of the polymer ion exchange membrane, the aqueous solution is not boiled and the bubbles and the polymer ion exchange membrane are not separated. In addition to causing no collision, the polymer ion exchange membrane is not heat-treated at a temperature above its glass transition temperature.
【００１１】この場合、加熱処理における水溶液を、高
分子イオン交換膜が陽イオンに対するイオン交換基を備
えた交換膜である場合には酸性水溶液とし、高分子イオ
ン交換膜が陰イオンに対するイオン交換基を備えた交換
膜である場合にはアルカリ性水溶液とした。このように
することで、イオン交換基からの結合を解かれた不純物
を、その極性に応じて酸性水溶液又はアルカリ性水溶液
中にイオンの状態で溶解させる。しかも、これら水溶液
を沸騰させないので、水分の蒸発を抑制することができ
る。In this case, the aqueous solution in the heat treatment is an acidic aqueous solution when the polymer ion exchange membrane is an exchange membrane having an ion exchange group for cations, and the polymer ion exchange membrane is an ion exchange group for anions. In the case of an exchange membrane provided with, an alkaline aqueous solution was used. By doing so, the impurities whose bonds have been released from the ion-exchange groups are dissolved in an ionic state in an acidic aqueous solution or an alkaline aqueous solution depending on the polarity. Moreover, since these aqueous solutions are not boiled, the evaporation of water can be suppressed.
【００１２】また、加熱処理における水溶液の下限温度
を４０℃とすることで、イオン交換基と金属イオン等の
不純物との結合を解くために必要な下限の熱エネルギー
を与えることができる。Further, by setting the lower limit temperature of the aqueous solution in the heat treatment to 40 ° C., it is possible to give the lower limit thermal energy required for breaking the bond between the ion exchange group and the impurities such as metal ions.
【００１３】更に、加熱処理する工程を加圧雰囲気下で
行なうことで、加圧前の水溶液の沸点が高分子イオン交
換膜のガラス転移点温度より低い場合には、水溶液の沸
点をガラス転移点温度に近づくよう上昇させる。このた
め、水溶液を沸騰させることはなくしかもそのガラス転
移点温度を下回る温度のうちのできるだけ高い温度で高
分子イオン交換膜を加熱処理することが可能となる。Further, when the boiling point of the aqueous solution before pressurization is lower than the glass transition temperature of the polymer ion exchange membrane, the boiling point of the aqueous solution is set to the glass transition point by performing the heat treatment step in a pressurized atmosphere. Increase to approach temperature. Therefore, the polymer ion-exchange membrane can be heat-treated at a temperature as high as possible out of the temperatures below the glass transition temperature thereof without boiling the aqueous solution.
【００１４】[0014]
【実施例】次に、本発明に係る高分子イオン交換膜の不
純物除去方法の一実施例について、説明する。本実施例
では、陽イオンの高分子イオン交換膜であるパーフルオ
ロカーボンスルフォン酸ポリマー膜（ナフィオン１１
７：商品名， Du Pont社製，乾燥時膜厚：約０．１８ｍ
ｍ）を処理する場合について説明する。EXAMPLE An example of the method for removing impurities from a polymer ion exchange membrane according to the present invention will be described below. In this example, a perfluorocarbon sulfonic acid polymer membrane (Nafion 11), which is a cation polymer ion exchange membrane, is used.
7: Product name, manufactured by Du Pont, film thickness when dried: about 0.18 m
The case of processing m) will be described.
【００１５】まず、このパーフルオロカーボンスルフォ
ン酸ポリマー膜（以下、実施例にあってはこの膜を陽イ
オン交換膜という）を処理に適したサイズに切断する。
その後、以下の工程を順次行なう。First, this perfluorocarbon sulfonic acid polymer membrane (hereinafter, this membrane is referred to as a cation exchange membrane in Examples) is cut into a size suitable for treatment.
Then, the following steps are sequentially performed.
【００１６】工程１：（第１の加熱処理）
上記の陽イオン交換膜を過酸化水素水の中に浸漬し、加
熱処理する。この時の過酸化水素水濃度は５〜３０ｗｔ
％（好ましくは５〜１０ｗｔ％）であり、加熱温度は６
０〜８０℃である。また、加熱処理時間は３０〜６０分
である。Step 1: (First heat treatment) The above cation exchange membrane is immersed in hydrogen peroxide solution and heat treated. The hydrogen peroxide concentration at this time is 5 to 30 wt.
% (Preferably 5 to 10 wt%) and the heating temperature is 6
It is 0 to 80 ° C. The heat treatment time is 30 to 60 minutes.
【００１７】工程２：（第１の洗浄処理）
過酸化水素水から取り出した陽イオン交換膜を、純水
（イオン交換水，イオン導電率；０．７μＳ／ｃｍ）中
にて加熱・洗浄する。この時の加熱温度は６０〜８０℃
であり、洗浄時間は１５〜６０分である。この工程１，
工程２を経ることで、陽イオン交換膜から油脂等の有機
成分を除去する。なお、純水は、０．５〜１．０μＳ／
ｃｍのイオン導電率を有するものであればよい（以下同
じ）。Step 2: (First Washing Treatment) The cation exchange membrane taken out from the hydrogen peroxide solution is heated and washed in pure water (ion exchanged water, ionic conductivity; 0.7 μS / cm). . The heating temperature at this time is 60 to 80 ° C.
And the cleaning time is 15-60 minutes. This step 1,
By passing through the step 2, organic components such as fats and oils are removed from the cation exchange membrane. Pure water is 0.5 to 1.0 μS /
Any material having an ionic conductivity of cm (the same applies hereinafter) may be used.
【００１８】工程３：（第２の加熱処理）
工程１，工程２を経た陽イオン交換膜を、硝酸を純水に
５〜１０ｗｔ％の濃度で溶解した希硝酸水溶液中で４０
℃を下限温度として加熱処理する。この時の処理条件
（加熱処理温度，処理時間，加圧圧力）は表１の通りで
ある。Step 3: (Second heat treatment) The cation exchange membrane obtained through Step 1 and Step 2 is placed in a dilute nitric acid solution prepared by dissolving nitric acid in pure water at a concentration of 5 to 10 wt%.
Heat treatment is performed at a temperature of ℃ as the lower limit. Table 1 shows the processing conditions (heat processing temperature, processing time, pressurizing pressure) at this time.
【００１９】工程４：（第２の洗浄処理）
希硝酸水溶液から取り出した陽イオン交換膜を、純水中
にて加熱・洗浄する。この時の加熱温度は６０〜８０℃
であり、洗浄時間は１５〜６０分である。この工程３，
工程４を経ることで、表１に示すように陽イオン交換膜
からケイ素（Ｓｉ），カリウム（Ｃａ）等の不純物（金
属イオン）を除去することができた。Step 4: (Second Washing Treatment) The cation exchange membrane taken out from the dilute nitric acid aqueous solution is heated and washed in pure water. The heating temperature at this time is 60 to 80 ° C.
And the cleaning time is 15-60 minutes. This step 3,
Through step 4, as shown in Table 1, impurities (metal ions) such as silicon (Si) and potassium (Ca) could be removed from the cation exchange membrane.
【００２０】工程５：（乾燥処理） 工程４までを経た陽イオン交換膜を真空乾燥する。Step 5: (drying treatment) The cation exchange membrane that has been subjected to step 4 is vacuum dried.
【００２１】次に、比較試験につて説明する。比較対象
とした陽イオン交換膜は、以下の通りである。
（１）工程１ないし工程５を経た陽イオン交換膜（実施
例処理品）
（２）工程１ないし工程５のうち工程３および工程４を
省略した陽イオン交換膜（未処理品）
（３）工程３に替えて陽イオン交換膜を沸騰処理し工程
１，工程２，工程４および工程５を実施例処理品と同様
に行なった陽イオン交換膜（沸騰処理品）
（４）工程１，工程２を行なった後、工程３の下限温度
（４０℃）を下回る温度で加熱処理しその後工程４およ
び工程５を実施例処理品と同様に行なった陽イオン交換
膜（範囲外処理品）
これらの陽イオン交換膜について行なった比較試験の結
果を表１に示す。なお、比較項目等は表１の通りであ
る。この場合、表１中、試料Ｎｏ．１が未処理品であ
り、試料Ｎｏ．２が範囲外処理品であり、試料Ｎｏ．３
が沸騰処理品であり、試料Ｎｏ．４〜８が実施例処理品
である。また、表１中の数値は、各試料についてこの試
料より得られた平均値である。Next, a comparative test will be described. The cation exchange membranes for comparison are as follows. (1) Cation-exchange membrane that has undergone steps 1 to 5 (treated product of Example) (2) Cation-exchange membrane obtained by omitting steps 3 and 4 of steps 1 to 5 (untreated product) (3) A cation exchange membrane (boiling treatment product) obtained by subjecting the cation exchange membrane to boiling treatment in place of step 3 and performing steps 1, 2 and 4 and step 5 in the same manner as the example treated product (4) step 1 and process After performing step 2, heat treatment was performed at a temperature lower than the lower limit temperature (40 ° C.) of step 3, and then steps 4 and 5 were performed in the same manner as the example treated product. Table 1 shows the results of a comparative test conducted on the cation exchange membrane. The comparison items are shown in Table 1. In this case, in Table 1, sample No. Sample No. 1 is an untreated product. Sample No. 2 is an out-of-range processed product. Three
Is a boiling treated product, and sample No. Nos. 4 to 8 are treated products of the example. The numerical values in Table 1 are average values obtained from each sample.
【００２２】ここで、実施例の陽イオン交換膜のガラス
転移点温度と工程３における加熱処理温度との関係につ
いて説明する。実施例の陽イオン交換膜（パーフルオロ
カーボンスルフォン酸ポリマー膜）のガラス転移点温度
は、１２０±５℃の範囲内の温度であり、温度に対する
弾性，粘性および位相差（ｔａｎδ）のそれぞれの値を
測定する実験から求めることができる。よって、表１に
おける試料Ｎｏ．７のように１００℃で加熱処理して
も、実施例の陽イオン交換膜をガラス転移点温度を越え
る温度で加熱することはない。また、表１に示すよう
に、試料Ｎｏ．８のように１２０℃で加熱処理した場
合、本実施例にあっては塑性変形が僅かしか認められな
かったことから、試料Ｎｏ．８はガラス転移点温度以上
の温度で加熱されてはおらず、試料Ｎｏ．８における加
熱処理温度（１２０℃）は、本実施例の処理に供した陽
イオン交換膜の実際のガラス転移点温度を下回る温度で
あったと考えられる。つまり、本実施例の処理に供した
陽イオン交換膜は、１２０℃を上記した範囲内で越える
温度、例えば１２４℃のガラス転移点温度を有するもの
であったといえる。よって、試料Ｎｏ．８における加熱
処理温度（１２０℃）は、不変的なものではなく、実際
に用いる陽イオン交換膜の実際のガラス転移点温度（１
２０±５℃の範囲内の温度）に応じて若干の変更が可能
である。具体的には、温度に対する弾性等の測定実験か
ら求めた陽イオン交換膜の実際のガラス転移点温度が１
１８℃であれば、試料Ｎｏ．８における加熱処理温度を
この１１８℃を下回る１１５℃に設定すればよいことに
なる。Here, the relationship between the glass transition temperature of the cation exchange membrane of the example and the heat treatment temperature in step 3 will be described. The glass transition temperature of the cation exchange membrane (perfluorocarbon sulfonic acid polymer membrane) of the example is a temperature within the range of 120 ± 5 ° C., and the respective values of elasticity, viscosity and phase difference (tan δ) with respect to temperature are shown. It can be determined from an experiment to measure. Therefore, the sample No. Even if heat treatment is carried out at 100 ° C. as in Example 7, the cation exchange membrane of the example is not heated at a temperature exceeding the glass transition temperature. In addition, as shown in Table 1, the sample No. In the case of heat treatment at 120 ° C. as in No. 8, only slight plastic deformation was observed in this example. Sample No. 8 was not heated at a temperature equal to or higher than the glass transition point temperature. It is considered that the heat treatment temperature (120 ° C.) in Example 8 was lower than the actual glass transition temperature of the cation exchange membrane used in the treatment of this example. That is, it can be said that the cation exchange membrane used in the treatment of this example had a glass transition temperature of 120 ° C. within the above range, for example, 124 ° C. Therefore, the sample No. The heat treatment temperature (120 ° C.) in No. 8 is not invariable, but the actual glass transition temperature (1
A slight change is possible depending on the temperature within the range of 20 ± 5 ° C.). Specifically, the actual glass transition temperature of the cation exchange membrane obtained from the measurement experiment of elasticity with respect to temperature is 1
If it is 18 ° C., the sample No. The heat treatment temperature in 8 may be set to 115 ° C., which is lower than 118 ° C.
【００２３】[0023]
【表１】 [Table 1]
【００２４】この表１から明らかなように、実施例処理
品（試料Ｎｏ．４〜８）では次の利点が認められる。
実施例処理品（試料Ｎｏ．４〜８）では、実施例処理
品における工程３を行なわない未処理品（試料Ｎｏ．
１）や、実施例処理品における工程３の下限温度（４０
℃）を下回る温度（２０℃）で加熱処理した範囲外処理
品（試料Ｎｏ．２）に比べて不純物の含有量を少なくす
ることができた。
実施例処理品のうちの加熱処理温度が６０℃以上のも
の（試料Ｎｏ．５〜８）では、未処理品（試料Ｎｏ．
１）に比べて不純物の含有量を半分以下にすることがで
きた。しかも、その含有量は、沸騰処理する沸騰処理品
（試料Ｎｏ．３）と同程度或いはそれ以下であった。
実施例処理品（試料Ｎｏ．４〜８）では、膜中の含水
率（最大含水率）を高めることができた。
実施例処理品（試料Ｎｏ．４〜８）では、未処理品
（試料Ｎｏ．１）や範囲外処理品（試料Ｎｏ．２）に比
べてイオン導電率，最大イオン導電率およびＩ−Ｖ特性
のそれぞれを向上させることができた。As is clear from Table 1, the following advantages are recognized in the processed products of the examples (Sample Nos. 4 to 8). In the processed products of the Examples (Sample Nos. 4 to 8), unprocessed products (Sample No. 4) in which the process 3 in the processed products of the Example is not performed.
1) and the lower limit temperature (40
It was possible to reduce the content of impurities as compared with the out-of-range treated product (Sample No. 2) which was heat-treated at a temperature (20 ° C.) lower than (° C.). Among the treated products of the examples, those having a heat treatment temperature of 60 ° C. or higher (Sample Nos. 5 to 8) were untreated (Sample No. 5).
Compared to 1), the content of impurities could be reduced to half or less. Moreover, the content was about the same as or less than that of the boil-treated product (sample No. 3) to be boiled. With the treated products of the examples (Sample Nos. 4 to 8), the water content (maximum water content) in the film could be increased. In the example treated products (Sample Nos. 4 to 8), the ionic conductivity, the maximum ionic conductivity and the IV characteristics are higher than those of the untreated product (Sample No. 1) and the out-of-range treated product (Sample No. 2). I was able to improve each.
【００２５】この，から次のような利点が判明す
る。つまり、一般に膜の含水率が低いと導電率が低下し
て内部抵抗が上がるため電圧が降下するが、実施例処理
品では上記したように高い含水率を有するとともに高い
導電率並びに高いＩ−Ｖ特性を備える。このため、実施
例処理品ではその内部抵抗を小さくできるので、実施例
処理品を電解質に用いた燃料電池の電池性能を向上させ
ることができる。From this, the following advantages are found. That is, in general, when the water content of the membrane is low, the electrical conductivity is lowered and the internal resistance is increased, so that the voltage is lowered, but the treated products of the example have a high water content and a high electrical conductivity and a high IV as described above. It has characteristics. For this reason, since the internal resistance of the treated product of the embodiment can be reduced, the cell performance of the fuel cell using the treated product of the embodiment as an electrolyte can be improved.
【００２６】実施例処理品のうちの加熱処理温度が６
０℃以上のもの（試料Ｎｏ．５〜８）では、イオン導電
率，最大イオン導電率およびＩ−Ｖ特性のそれぞれをよ
り一層向上させることができた。この傾向は、加圧環境
下で高温度の工程３を行なう実施例処理品（試料Ｎｏ．
７，８）で顕著であった。
沸騰処理品（試料Ｎｏ．３）に顕著なしわや凹凸が見
られ塑性変形が観察されたのに対して、実施例処理品で
は塑性変形がない（試料Ｎｏ．４〜７）か或いは僅かな
塑性変形しか認められなかった（試料Ｎｏ．８）。The heat treatment temperature of the treated products of the example is 6
In the case of 0 ° C. or higher (Sample Nos. 5 to 8), the ionic conductivity, the maximum ionic conductivity and the IV characteristics could be further improved. This tendency is due to the processed product of the example (Sample No.
7, 8) was remarkable. While remarkable wrinkles and unevenness were observed in the boiling treated product (Sample No. 3) and plastic deformation was observed, there was no plastic deformation in the Example processed product (Samples No. 4 to 7) or a slight amount. Only plastic deformation was observed (Sample No. 8).
【００２７】次に、加熱処理温度が同じでありながら、
僅かな塑性変形しか認められなかった実施例処理品（試
料Ｎｏ．７）と顕著な塑性変形が観察された沸騰処理品
（試料Ｎｏ．３）とについて、水素ガス（加湿水素ガ
ス）のガス透過係数を測定した。その結果を表２に示
す。なお、測定条件は膜を挟んだ差圧が１気圧であり、
測定にはガスクロマトグラフィーを用い、膜を透過する
水素ガスの濃度を測定した。Next, while the heat treatment temperature is the same,
Gas permeation of hydrogen gas (humidified hydrogen gas) between the treated product of Example (Sample No. 7) in which only slight plastic deformation was observed and the boiling treated product (Sample No. 3) in which remarkable plastic deformation was observed. The coefficient was measured. The results are shown in Table 2. The measurement condition is that the pressure difference across the membrane is 1 atm,
Gas chromatography was used for the measurement, and the concentration of hydrogen gas passing through the membrane was measured.
【００２８】[0028]
【表２】 [Table 2]
【００２９】この表２から明らかなように、水溶液を加
圧環境下で沸騰させない実施例処理品（試料Ｎｏ．７）
では、沸騰させる沸騰処理品（試料Ｎｏ．３）の半分の
ガス透過係数となった。よって、実施例処理品（試料Ｎ
ｏ．７）によれば、水素がガス状のまま過剰に透過して
しまうことを防止でき、実施例処理品（試料Ｎｏ．７）
を電解質とする燃料電池の特性を向上させることができ
る。なお、試料Ｎｏ．８についても、水溶液を加圧環境
下で沸騰させないことから、実施例処理品（試料Ｎｏ．
７）と同様の結果が得られた。As is clear from Table 2, the treated product of the example (Sample No. 7) in which the aqueous solution is not boiled under a pressurized environment.
Then, the gas permeation coefficient was half that of the boiling treated product to be boiled (Sample No. 3). Therefore, the processed product of the example (Sample N
o. According to 7), hydrogen can be prevented from permeating excessively in a gaseous state, and the processed product of the example (Sample No. 7).
It is possible to improve the characteristics of the fuel cell using the electrolyte as the electrolyte. Sample No. As for No. 8 as well, since the aqueous solution was not boiled under a pressurized environment, it was treated in the Example (Sample No. 8).
Results similar to 7) were obtained.
【００３０】以上説明したように、本実施例の不純物除
去方法によれば、陽イオン交換膜を塑性変形させること
なく膜中の不純物を除去することができる。そして、膜
中不純物が少ないことに起因して膜のイオン交換機能の
維持を図ることができる。よって、本実施例の処理が施
された実施例処理品を燃料電池の電解質として利用すれ
ば、高いＩ−Ｖ特性に基づいて燃料電池の特性を向上す
ることができる。As described above, according to the impurity removing method of the present embodiment, the impurities in the cation exchange membrane can be removed without plastically deforming the membrane. The ion exchange function of the membrane can be maintained due to the small amount of impurities in the membrane. Therefore, by using the treated product of the embodiment, which has been subjected to the treatment of this embodiment, as the electrolyte of the fuel cell, the characteristics of the fuel cell can be improved based on the high IV characteristics.
【００３１】また、本実施例の不純物除去方法では、１
００℃や１２０℃といった高温度で陽イオン交換膜を加
熱処理するに際して水溶液を沸騰させない。このため、
この加熱処理をガラス容器中で行なっても容器壁面から
ケイ素等のガラス成分を純水中に溶出させることがな
い。つまり、本実施例の不純物除去方法では、純水中に
おける不純物を陽イオン交換膜から除去したものに限る
ことができる。この結果、本実施例の不純物除去方法に
よれば、純水のイオン導電率を不用意に低下させること
がなく長期に亘って純水のイオン導電率を低い値に維持
することができる。また、本実施例の不純物除去方法に
よれば、水溶液を沸騰させないので水分の蒸発を抑制し
てその濃度（本実施例では硝酸濃度）を維持することが
でき、処理品質（不純物の除去程度等）を一定に維持す
ることができる。Further, in the impurity removing method of this embodiment, 1
The aqueous solution is not boiled when the cation exchange membrane is heat-treated at a high temperature of 00 ° C or 120 ° C. For this reason,
Even if this heat treatment is performed in a glass container, glass components such as silicon will not be eluted from the wall surface of the container into pure water. That is, in the impurity removal method of this embodiment, the impurities in pure water can be removed from the cation exchange membrane. As a result, according to the impurity removing method of the present embodiment, the ionic conductivity of pure water can be maintained at a low value for a long period of time without carelessly reducing the ionic conductivity of pure water. Further, according to the impurity removal method of the present embodiment, since the aqueous solution is not boiled, it is possible to suppress the evaporation of water and maintain its concentration (nitric acid concentration in this embodiment), and the treatment quality (degree of removal of impurities, etc.) ) Can be kept constant.
【００３２】更に、本実施例の不純物除去方法では、第
２の加熱処理の工程（工程３）後に洗浄する際に、加熱
するよう構成したので、不純物を水溶液に効果的に溶解
させて洗浄効果を高めることができる。また、本実施例
の不純物除去方法では、陽イオン交換膜を加熱処理する
ための水溶液として希硝酸水溶液を用いたので、希硝酸
の有する高い酸化力により、他の酸の水溶液、例えば希
硫酸水溶液を用いる場合に比べて洗浄効果を高めること
ができる。Further, in the impurity removing method of the present embodiment, since the heating is carried out when cleaning after the second heat treatment step (step 3), the impurities are effectively dissolved in the aqueous solution and the cleaning effect is obtained. Can be increased. Further, in the method of removing impurities of the present embodiment, since the dilute nitric acid aqueous solution was used as the aqueous solution for heat-treating the cation exchange membrane, the aqueous solution of another acid, for example, dilute sulfuric acid aqueous solution, was used due to the high oxidizing power of the dilute nitric acid. The cleaning effect can be enhanced as compared with the case of using.
【００３３】以上本発明の一実施例について説明した
が、本発明はこの様な実施例になんら限定されるもので
はなく、本発明の要旨を逸脱しない範囲において種々な
る態様で実施し得ることは勿論である。Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment and can be implemented in various modes without departing from the scope of the present invention. Of course.
【００３４】例えば、パーフルオロカーボンスルフォン
酸ポリマー膜の外、ポリスチレンジビニルベンゼンスル
フォン酸ポリマー膜等の陽イオン交換膜であってもよ
い。For example, in addition to the perfluorocarbon sulfonic acid polymer membrane, a cation exchange membrane such as a polystyrene divinylbenzene sulfonic acid polymer membrane may be used.
【００３５】[0035]
【発明の効果】以上詳述したように請求項１ないし請求
項４記載の高分子イオン交換膜の不純物除去方法では、
加熱処理に供する水溶液を沸騰させることはないととも
に、高分子イオン交換膜をそのガラス転移点温度以上の
温度で加熱処理することはない。この結果、本発明の各
請求項記載の不純物除去方法によれば、高分子イオン交
換膜を塑性変形させることなく膜中の不純物を除去する
ことができ、膜中不純物の除去を通して膜のイオン交換
機能の維持を図ることができる。As described in detail above, in the method for removing impurities from the polymer ion exchange membrane according to any one of claims 1 to 4,
The aqueous solution used for the heat treatment is not boiled, and the polymer ion exchange membrane is not heat treated at a temperature higher than its glass transition temperature. As a result, according to the method for removing impurities in the claims of the present invention, the impurities in the membrane can be removed without plastically deforming the polymer ion exchange membrane, and the ion exchange of the membrane can be performed through the removal of the impurities in the membrane. The function can be maintained.
【００３６】請求項２記載の高分子イオン交換膜の不純
物除去方法で高温度によれば、高分子イオン交換膜の加
熱処理に際して水溶液を沸騰させないので、水溶液の水
分の蒸発を抑制して水溶液濃度を維持することができ、
不純物の除去程度を一定に維持することができる。According to the method for removing impurities from the polymer ion exchange membrane of the present invention, when the high temperature is used, the aqueous solution is not boiled during the heat treatment of the polymer ion exchange membrane. Can be maintained
The degree of removal of impurities can be kept constant.
【００３７】請求項４記載の高分子イオン交換膜の不純
物除去方法で高温度によれば、水溶液の沸点を上昇させ
てより高い温度での加熱処理を可能とし、高分子イオン
交換膜を塑性変形させることなく膜中の不純物をより効
果的に除去することができる。According to the method for removing impurities of a polymer ion exchange membrane according to claim 4, when the high temperature is used, the boiling point of the aqueous solution is raised to enable heat treatment at a higher temperature, and the polymer ion exchange membrane is plastically deformed. The impurities in the film can be removed more effectively without performing the above.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) B01J 47/12 B01J 49/00 ─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. 7 , DB name) B01J 47/12 B01J 49/00
Claims (4)
交換基を備え陽陰いずれかのイオンを選択的に透過する
高分子イオン交換膜の不純物除去方法であって、 前記高分子イオン交換膜を水溶液中で加熱処理する工程
を含み、 該工程における加熱処理温度を前記水溶液の沸点又は前
記高分子イオン交換膜のガラス転移点温度のいずれか低
い方の温度を下回る温度としたことを特徴とする高分子
イオン交換膜の不純物除去方法。1. A method for removing impurities from a polymer ion exchange membrane, which comprises an ion exchange group for a cation or an anion and selectively permeates either a cation or anion, wherein the polymer ion exchange membrane is in an aqueous solution. And a heat treatment temperature in the step is set to a temperature lower than the lower one of the boiling point of the aqueous solution and the glass transition temperature of the polymer ion exchange membrane, whichever is lower. Method for removing impurities from ion exchange membrane.
分子イオン交換膜が陽イオンに対するイオン交換基を備
えた交換膜である場合には酸性水溶液であり、前記高分
子イオン交換膜が陰イオンに対するイオン交換基を備え
た交換膜である場合にはアルカリ性水溶液である請求項
１記載の高分子イオン交換膜の不純物除去方法。2. The aqueous solution in the heat treatment is an acidic aqueous solution when the polymer ion exchange membrane is an exchange membrane having ion exchange groups for cations, and the polymer ion exchange membrane for anions. The method for removing impurities from a polymer ion exchange membrane according to claim 1, wherein the exchange membrane having an ion exchange group is an alkaline aqueous solution.
を４０℃とした請求項１，請求項２いずれか記載の高分
子イオン交換膜の不純物除去方法。3. The method for removing impurities from a polymer ion exchange membrane according to claim 1, wherein the lower limit temperature of the aqueous solution in the heat treatment is 40 ° C.
行なう請求項１，請求項２，請求項３いずれか記載の高
分子イオン交換膜の不純物除去方法。4. The method for removing impurities from a polymer ion exchange membrane according to claim 1, wherein the heat treatment step is performed in a pressurized atmosphere.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24365593A JP3489148B2 (en) | 1993-09-03 | 1993-09-03 | Method for removing impurities from polymer ion exchange membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24365593A JP3489148B2 (en) | 1993-09-03 | 1993-09-03 | Method for removing impurities from polymer ion exchange membrane |
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| Publication Number | Publication Date |
|---|---|
| JPH0768186A JPH0768186A (en) | 1995-03-14 |
| JP3489148B2 true JP3489148B2 (en) | 2004-01-19 |
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|---|---|---|---|
| JP24365593A Expired - Fee Related JP3489148B2 (en) | 1993-09-03 | 1993-09-03 | Method for removing impurities from polymer ion exchange membrane |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| IT1296949B1 (en) * | 1997-12-10 | 1999-08-03 | De Nora Spa | POLYMER MEMBRANE FUEL CELL OPERATING AT TEMPERATURE ABOVE 100 ° C |
| JP2000348740A (en) * | 1999-06-08 | 2000-12-15 | Ibiden Co Ltd | Separator of solid high polymer type fuel cell and its manufacture |
| JP3475869B2 (en) | 1999-09-17 | 2003-12-10 | 松下電器産業株式会社 | Polymer electrolyte fuel cell and method for recovering its characteristics |
| JP3898707B2 (en) * | 2004-05-10 | 2007-03-28 | 行政院原子能委員會核能研究所 | Manufacturing method of fuel cell membrane electrode assembly manufactured by printing process |
| US20080090126A1 (en) * | 2004-10-05 | 2008-04-17 | Shigeyuki Unoki | Preservation Method Of Polymer Electrolyte Membrane Electrode Assembly Technical Field |
| NZ563797A (en) * | 2005-06-20 | 2010-07-30 | Fuel Pty Ltd V | Improved perfluorinated membranes and improved electrolytes for redox cells and batteries |
| TWI389970B (en) * | 2007-09-25 | 2013-03-21 | Thermosetting light reflecting resin composition, optical semiconductor element-mounting substrate using the same, method for manufacturing the same, and optical semiconductor device | |
| FR2936104A1 (en) * | 2008-09-12 | 2010-03-19 | Rech S De L Ecole Nationale Su | Process to conduct the operation of a fuel cell, comprises introducing a determined quantity of catalyst in a hydrogen stream or oxygen stream for the hydrolysis of sulfonic anhydrides formed during the functioning of the cell |
| RU2573836C1 (en) * | 2014-10-21 | 2016-01-27 | ЭлДжи КЕМ, ЛТД. | Method of reducing membrane permeability with respect to vanadium ions and membrane made using said method |
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