What are the different types of ion-exchange resins?

2.1. Ion exchange resins consists of two main types, i.e., cation exchange resins, that exchange positively charged ions, such as sodium, for calcium, and anion exchange resins, that exchange negatively charged ions, such as chloride, for arsenic.

What does anion exchange do?

Anion exchange devices remove anions (negatively charged ions such as arsenic and nitrate) and replace them with chloride. Mixed media ion exchange units remove both cations and anions. A typical mix would be 60 percent cation exchange material and 40 percent anion exchange material.

What does anion resin remove?

Cation and anion resins remove dissolved ionic contaminants. Anion IX resins include a strong/weak anion, such as OH- and Cl-. Acting together or alone, these types remove many ionic contaminants from water. Neither type removes non-ionic contaminants such as benzene.

Which functional group is present in anion exchange resin?

The functional groups are sulfonic (–SO3H), carboxylic (–COOH), or phosphonic (–PO32 −) acids for resins capable of exchanging cations, whereas anion exchange resins possess basic functional groups, such as quaternary ammonium or ammine groups (Korkisch, 1989).

What are anion resins?

Anion resins and cation resins are the two most common resins used in the ion-exchange process. While anion resins attract negatively charged ions, cation resins attract positively charged ions.

What is the difference between cation and anion exchange resins?

Cation and anion exchange resins can be thought of as powerful magnets that attract and hold the contaminating minerals from the passing source water, by an electromagnetic attraction. Cation resins naturally attract a certain set of minerals, while anion resins attract another set of minerals.

What is an ion exchange resin used for?

Ion-exchange resins are widely used in different separation, purification, and decontamination processes . The most common examples are water softening and water purification . In many cases ion-exchange resins were introduced in such processes as a more flexible alternative to the use of natural or artificial zeolites.

Why do anion exchange resins smell?

Anion exchange resins, in general but especially strong base anion exchange resins in the hydroxide form, may release odors such as a dead fish smell. The main reason is the release of very low levels of alkyl-amines from the resin (i.e.: trimethylamine from Type I strong base resins).

What does ion exchange resin mean?

An ion-exchange resin or ion-exchange polymer is a resin or polymer that acts as a medium for ion exchange . It is an insoluble matrix (or support structure) normally in the form of small (0.25-0.5 mm radius) microbeads, usually white or yellowish, fabricated from an organic polymer substrate.