lon exchange (IX) is a powerful chemical technology, through a reversible chemical reaction, where dissolved ions are removed fromsolution and replaced with other ions of the same or similar electrical charge. IX resin facilitates IX reactions. The resin itself is composed of organic polymers that forms a network of hydrocarbons, and IX sites, called"functional group" throughout the matrix. The IX sites attract ions of an opposing charge, which give the IX its separation capabilities.
The unique properties of IX resins are due to their special internal structure, which is the combination of physical and chemical action, consists of three parts:
1. A small bead composed of a polymer crosslinked skeleton,which is mainly composed of styrene and acrylic acid matrix.
2. There are many pores in the inside of the bead, macroporous, Gel-porous.
3. IX groups, bonded to the pores and surfaces, which decide their applications (see basic types of ion exchange resins for details)
The weak acid cation exchange resin(WAC) is the type of IX resin with functional group of carboxylic acid group (-COOH). They show weak acidity like acetic acid, having the ability to exchange with bases such as NaOH and weak acid salts such as NaHCO3.
The WAC resins have two kinds of chemical structures, a methacrylic acid type and an acrylic acid type. This makes a difference for the ion exchange ability. The methacrylic acid type can be used at pH above 5, while the acrylic acid type can be used at pH above 4. Even though use is restricted, it is easier to regenerate than a SAC resin.
WAC Resins are suitable in the fields of removal of water dealkalization, carbonate hardness, purification of antibiotics and amion acid. It is not used much for water processing because of the less acidity, but for antibiotic and amino acid purification.
Typical Applications For WAC Resin
●Bicarbonate alkalinity from water
●Transition metals recovery
●Purification of antibiotics and amion acid