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

İyon değişimi, yüklü molekülleri, zıt yüklü durağan faz ile ilişkili hareketli veya 'aktif' iyonlarla tersinir bir şekilde değiştirerek bir çözeltiden ayırır.
Sabit faz genellikle gözenekli ancak çözünmeyen bir katıdır, örneğin iyonik fonksiyonel gruplar taşıyan çok sayıda monomere sahip yüksek moleküler ağırlıklara sahip çapraz bağlı organik polimerler.
Aktif katyonlara sahip anyonik polimerler katyon değiştiricilerdir, aktif anyonlara sahip katyonik polimerler ise anyon değiştiricilerdir.
Katyonik ve anyonik değiştiriciler ayrıca fonksiyonel gruplarına göre zayıf ve güçlü olarak sınıflandırılır.
İyon değiştiricilere bağlı hareketli iyonlar çözeltiye göç eder ve dengeye ulaşılana kadar çözeltiden benzer şekilde yüklü iyonlarla değiştirilir.
Kütle etkisi yasasının iyon değişim dengesine uygulanması, reaksiyon için seçicilik katsayısını ifade eder.
Tükenmiş katyonik ve anyonik değiştiriciler, sırasıyla fazla asidik veya bazik çözeltilerle yıkanarak rejenere edilir.

İyon değişimi

Ion Exchange

İyon değiştirme kromatografisi, yüklü molekülleri bir çözeltiden, zıt yüklü durağan faz ile ilişkili olan mobil veya aktif iyonlar ile tersinir bir şekilde değiştirir. Bu yöntem iyonları ayırmak, suyu yumuşatmak ve deiyonize etmek ve çözeltileri saflaştırmak için kullanılabilir. İyon değiştirme kolonunu oluşturan polimerler yüksek molekül ağırlıklı ve kimyasal olarak stabil polimerlerdir, gözenekli olacak şekilde çapraz bağlanırlar ve esas olarak çözünmezler. Ayrıca asidik veya bazik gruplarla işlevselleştirilirler. Asidik gruplarla işlevselleştirildiğinde kolonlar veya reçineler katyon değiştiriciler olarak bilinir ve pozitif karşı iyonlara sahip negatif yüklü polimerler içerir. Bunlar katyonların mobil fazdan değiştirilmesine izin verir. Bazik gruplarla işlevselleştirildiğinde kolonlar veya reçine, negatif karşı iyonlara sahip pozitif yüklü polimerler içeren ve çözeltideki anyonları değiştiren anyon değiştiriciler olarak bilinir.

İyon değişimi sırasında, katı fazdaki polimerlerle ilişkili karşıt iyonlar çözeltiye girerken, çözeltideki iyonlar kendi yerlerinde polimerle etkileşime girer. Çapraz bağlanmanın boyutu arttıkça ve polimerdeki iyon değiştirme gruplarının sayısı arttıkça iyon değiştirme yeteneğinin de arttığına dikkat edin. Bu değişim tersine çevrilebilir ve denge sağlanana kadar devam eder.

Asit katyon değiştiriciler, polistiren sülfonik asitte görülen sülfonik asit (−SO3H) gibi güçlü asitlerle veya poli(metil metilakrilik) asitte görülen karboksilik asit (−COOH) gibi zayıf asitlerle işlevselleştirilebilir. Benzer şekilde anyon değiştiriciler de güçlü ve zayıf olarak sınıflandırılır. Güçlü anyon değiştiriciler genellikle polistiren dördüncül amonyum klorürdekiler gibi dörtlü amonyum grupları (−CH2N(CH3)3+) içerir ve zayıf anyon değiştiriciler genellikle polistiren tersiyer amin hidroksitteki gibi ikame edilmiş aminlerle (−NH3+) işlevselleştirilir. .

İyon Değişimi

İyon değişimi, yüklü molekülleri, iyonlarla ilişkili mobil veya 'aktif' iyonlarla tersine çevrilebilir bir şekilde değiştirerek bir çözeltiden ayırır.

Education

JoVE Core

Analytical Chemistry

Analitik Kimya

Unit 1

Ünite 1

Introduction to Separation Methods

Ayrıştırma Yöntemlerine Giriş

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

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

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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 Analitik Kimya, karmaşık kimyasal prensiplerini anlaşılır, ilgi çekici animasyonlara dönüştürerek basitleştirir ve SI Birimlerinden NMR spektroskopisine kadar konuları daha erişilebilir ve anlaşılır hale getirir. Buna ek olarak, bilim insanlarının yer aldığı videolar, bu kavramların dünya çapındaki laboratuvarlarda yürütülen gerçek dünya araştırmalarındaki uygulamalarını gösterir.

analytical chemistry

Ion Exchange Resins and Charged Molecules

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