The main difference between these two water treatment processes is that cation exchange removes positively charged ions, while anion exchange removes negatively charged ions.
Cation exchange involves the replacement of cations, or ions with a positive charge, in the water with positively charged ions that are pre-loaded on a resin or exchange material.
Cation exchange uses a type of ion exchange resin that’s effective in removing cations such as calcium, magnesium, and heavy metals (like iron) from the water.
Anion exchange uses a very similar process to cation exchange – the main difference is that the resin charge and the anions being exchanged have opposite charges.
Anion resins can remove sulfate, nitrate, chloride, bicarbonate, arsenic, fluoride, and more.