Cation Exchange Resin:
Cation exchange resin is a type of chromatographic resin that selectively binds and separates cations from a mixture. It contains negatively charged functional groups, such as sulfonic acid (-SO3-) or carboxylic acid (-COOH), which attract and exchange cations in a solution.

Anion Exchange Resin:
Anion exchange resin, on the other hand, is a type of chromatographic resin that selectively binds and separates anions from a mixture. It contains positively charged functional groups, such as quaternary ammonium (-NR4+) or tertiary amine (-NR3+), which attract and exchange anions in a solution.

Differences between Cation and Anion Exchange Resins:
1. Functional Groups:
- Cation exchange resin contains negatively charged functional groups (sulfonic acid or carboxylic acid) that attract cations.
- Anion exchange resin contains positively charged functional groups (quaternary ammonium or tertiary amine) that attract anions.

2. Ion Selectivity:
- Cation exchange resin selectively binds and separates cations from a mixture, while allowing anions to pass through.
- Anion exchange resin selectively binds and separates anions from a mixture, while allowing cations to pass through.

3. Chromatographic Separation:
- Cation exchange resin can be used to separate cations based on their charge and size. Cations with higher charges or smaller sizes will have stronger interactions with the resin and will elute later, while cations with lower charges or larger sizes will elute earlier.
- Anion exchange resin can be used to separate anions based on their charge and size. Anions with higher charges or larger sizes will have stronger interactions with the resin and will elute later, while anions with lower charges or smaller sizes will elute earlier.

4. Applications:
- Cation exchange resin is commonly used in various applications, such as water softening, metal recovery, and purification of organic compounds.
- Anion exchange resin is widely used in applications like water treatment, sugar refining, and pharmaceutical purification processes.

5. Regeneration:
- Cation exchange resin can be regenerated by passing a solution of higher concentration of cations, such as hydrochloric acid or sodium chloride, through the resin bed. This displaces the previously bound cations and restores the exchange capacity of the resin.
- Anion exchange resin can be regenerated by passing a solution of higher concentration of anions, such as sodium hydroxide or ammonium hydroxide, through the resin bed. This displaces the previously bound anions and restores the exchange capacity of the resin.

In conclusion, cation exchange resin and anion exchange resin have opposite charges and selectively bind and separate cations and anions, respectively. They differ in their functional groups, ion selectivity, chromatographic separation, applications, and regeneration processes.