Produce pure water with a resistivity of 10-15 M Ω• cm from the pre purification column.
The ion exchange method uses spherical resin（ion exchange resin）Filter the source water, and the ions in the water will exchange with the ions fixed on the resin. The two common ion exchange methods areHard water softeningAnd the deionization method. Hard water softening is mainly used as a pre-treatment procedure to reduce the hardness of water before reverse osmosis (RO) treatment. The spherical resin inside the softening machine softens water by exchanging two sodium ions for one calcium ion or magnesium ion.

　　Cation exchange resin and anion exchange resin are mixed together and placed in the same ion exchange bed.Ion exchange resins use hydrogen ions to exchange cations and hydroxide ions to exchange anions; Made from styrene and divinylbenzene containing sulfonic acid groupscation exchange resinIt will exchange various cations (such as Na+, Ca2+, Al3+) encountered through hydrogen ion exchange. Similarly, made from styrene containing quaternary ammonium saltsanion-exchange resinIt will exchange various anions (such as Cl -) encountered through hydroxide ion exchange. The hydrogen ions released from the cation exchange resin combine with the hydroxide ions released from the anion exchange resin to produce pure water.