Ion exchange involves the exchange of undesirable cations or anions with more benign cations or anions on the surface of a polystyrene resin. The resin is then regenerated using a concentrated brine solution.
Ion exchange can be used to resolve hardness, treat nitrates, remove radium and many other contaminants extremely effectively.
Ion exchange has been successfully used to remove PFOAs from drinking water using a strong basic resin.