Name: ion exchange resins and charged molecules
Uploaded: 2024-04-04T10:51:25.000Z
Duration: 1 min 17 s
Channel: JoVE

イオン交換は、逆に荷電した固定相に関連する移動性イオン、つまり「活性」イオンと可逆的に交換することにより、荷電分子を溶液から分離します。
固定相は通常、イオン性官能基を持つ多数のモノマーを持つ高分子量の架橋有機ポリマーなど、多孔質であるが不溶性の固体です。
活性カチオンを持つアニオン性ポリマーは陽イオン交換体であり、活性陰イオンを持つカチオン性ポリマーは陰イオン交換体です。
カチオン性交換体とアニオン性交換体は、それらの官能基に基づいてさらに弱いと強いと分類されます。
イオン交換体に付着した移動性イオンは溶液中に移動し、平衡に達するまで溶液からの同様に荷電したイオンと置換されます。
質量作用法則をイオン交換平衡に適用すると、反応の選択性係数が表されます。
排出されたカチオン性交換体および陰イオン性交換体は、それぞれ過剰な酸性溶液または塩基性溶液で洗浄することによって再生されます。

イオン交換

Ion Exchange

イオン交換クロマトグラフィーは、帯電した分子を、逆に帯電した固定相に関連付けられた移動イオンまたは「活性」イオンと可逆的に交換することにより、溶液から分離します。この方法は、イオンの分離、水を軟化および脱イオン化し、溶液を精製するために使用できます。イオン交換カラムを構成するポリマーは、高分子量で化学的に安定したポリマーであり、架橋されて多孔質になり、本質的に不溶性になります。また、酸性基または塩基性基のいずれかで官能化されています。酸性基で官能化すると、カラムまたは樹脂は陽イオン交換体として知られ、正の対イオンを持つ負に帯電したポリマーが含まれます。これらにより、移動相からのカチオンの交換が可能になります。塩基性基で官能化すると、カラムまたは樹脂は陰イオン交換体として知られ、負の対イオンを持つ正に帯電したポリマーが含まれ、溶液から陰イオンを交換します。

イオン交換中、固相ポリマーに関連する対イオンが溶液に入り、溶液からのイオンがその場所でポリマーと相互作用します。架橋の程度が増加し、ポリマー内のイオン交換基の数が増加すると、イオン交換能力が増加することに注意してください。この交換は可逆的であり、平衡が確立されるまで継続します。

酸性陽イオン交換体は、ポリスチレンスルホン酸に見られるスルホン酸 (-SO3H) などの強酸、またはポリ(メチルメチルアクリル) 酸に見られるカルボン酸 (-COOH) などの弱酸のいずれかで官能化できます。同様に、陰イオン交換体は強または弱に分類されます。強陰イオン交換体には、ポリスチレン四級アンモニウム塩化物などの四級アンモニウム基 (-CH2N(CH3)3+) が含まれることが多く、弱陰イオン交換体は、ポリスチレン三級アミン水酸化物などの置換アミン (-NH3+) で官能化されていることがよくあります。

イオン交換は、荷電分子を溶液に関連する可動性または「活性」イオンと可逆的に交換することにより、溶液から荷電分子を分離します...

Education

JoVE Core

Analytical Chemistry

分析化学

Unit 1

ユニット1

Introduction to Separation Methods

分離手法概論

KEY TERMS AND CONCEPTS

重要用語と概念

ion exchange resins and charged molecules

Ion exchange chromatography separates charged molecules from a solution by swapping them with mobile, or active, ions on a stationary phase. It is used to separate ions, soften and deionize water, and purify solutions. The method depends on a solid column made of high-molecular-weight, chemically stable polymers that are crosslinked to make them porous and essentially insoluble.

These polymers are functionalized with either acidic or basic groups. When acidic groups are present, the resin is a cation exchanger. It has a negatively charged polymer with positive counterions, so it can exchange cations from the mobile phase.

When basic groups are present, the resin is an anion exchanger. It has a positively charged polymer with negative counterions, so it can exchange anions from the solution. During ion exchange, the counterions on the solid polymer move into the solution, and ions from the solution take their place.

The exchange is reversible and continues until equilibrium is reached. The ability to exchange ions increases when the polymer has more crosslinking and more ion-exchange groups. Cation exchangers can be strong or weak. Strong cation exchangers often use sulfonic acid groups, such as in polystyrene sulfonic acid, while weak cation exchangers often use carboxylic acid groups, such as in poly(methyl methylacrylic) acid.

Anion exchangers are also classified as strong or weak. Strong anion exchangers often contain quaternary ammonium groups, such as in polystyrene quaternary ammonium chloride. Weak anion exchangers are often functionalized with substituted amines, such as in polystyrene tertiary amine hydroxide.

Ion Exchange Resins and Charged Molecules

ion-exchange-resins-and-charged-molecules

states of matter and phase changes

Heating and Cooling During Phase Changes

Heating and cooling can change a substance from one state of matter to another. These phase changes depend on internal energy, which is the total kinetic energy of particles and the potential energy from their interactions. In the condensed phases, stronger intermolecular forces and the pressure on the substance affect that internal energy. The internal energy is highest in the gaseous state, lowest in the solid state, and in between for the liquid state. Phase transitions happen when...

distillation: vapor&ndash;liquid equilibria

Distillation and Boiling Point Changes

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filtration

Filtration Setup and Filtrate Collection

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Recrystallization for Purifying Solid Compounds

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Crystal Formation Through Supersaturation

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precipitation and co-precipitation

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Wastewater Cleanup by Coagulation

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Solvent partitioning in chemical extraction describes how a solute spreads between two immiscible solvents. Immiscible solvents do not mix, such as an aqueous phase and an organic phase. The distribution law, also called Nernst's distribution law or the partition law, explains how that solute is shared at a constant temperature and equilibrium. At equilibrium, the ratio of solute concentrations in the two solvents stays constant. For extraction from water into an organic solvent, this...

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pH Control in Liquid Extraction

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Chelate Extraction for Metal Ion Separation

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Chromatography: Separation by Polarity

Chromatography separates compounds by how they divide between a stationary phase and a mobile phase. The stationary phase is the material that holds the compounds for a time. The mobile phase is the solvent that carries the solutes to be analyzed. In column chromatography, a mixture flows through the stationary phase. The compounds separate based on their structure and polarity. Solutes that interact weakly with the stationary phase move faster through the column and exit first. Solutes that...

dialysis

Dialysis Separation by Diffusion

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volatilization

Mass Loss in Gravimetric Analysis

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ion exchange

Ion exchange chromatography separates charged molecules from a solution by swapping them with mobile, or active, ions on a stationary phase. It is used to separate ions, soften and deionize water, and purify solutions. The method depends on a solid column made of high-molecular-weight, chemically stable polymers that are crosslinked to make them porous and essentially insoluble. These polymers are functionalized with either acidic or basic groups. When acidic groups are present, the resin is a...

key terms and concepts

Learn how ion exchange chromatography uses cation and anion exchangers to separate charged molecules, purify solutions, and soften water.

Ion Exchange Resins and Charged Molecules | JoVE K12

JoVE Core 分析化学 は、複雑な化学原理をアニメーションで視覚化することで、SI 単位から NMR 分光法を含むトピックをよりわかりやすくします。実験を撮影した実写動画では、これらの概念が世界中の研究所でどのように応用されているかを取り上げています。

analytical chemistry

Ion Exchange Resins and Charged Molecules

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