The Collaborative International Dictionary
deionized \de*i"on*ized`\ a. (Chem.) freed from ions by a process of deionization; as, deionized water.
Note: In chemistry and biochemistry, experiments often require water free from contaminating ions, and the ordinary distilled water may be subjected to a process of deionization in order to render the ion content sufficiently low so as not to interfere with the investigation.
Wiktionary
That has been prepared by deionization v
(en-past of: deionize)
Usage examples of "deionized".
He could taste the familiar tang of museum air—an arid, deionized essence that carried a faint hint of carbon—the product of industrial, coal-filter dehumidifiers that ran around the clock to counteract the corrosive carbon dioxide exhaled by visitors.