Ion Exchange (IEX)
Ion exchange resins used in the sugar industry as de-colourizers are of the strong-base anionic
type, with quaternary amine functional groups. They are operated in the chloride form. There are
two basic mechanisms for colorant fixation to strong base anion. Ion exchange resins: ionic
bonding between anionic colorants and the resin’s fixed charges, and hydrophobic interaction
between non-polar parts of the colorant and the styrene di-vinyl benzene resin matrix. Since
most sugar colorants are anionic in nature, being charged negatively, strong base anionic resins
are efficient decolourizers