Millipore Corporation

Kitty K Siu

Gary C Ganzi

Anil D Jha

Gary A O'Neill

Jeffrey P Denoncourt

Ultrapure water containing less than 10 ppt total ions, other than hydrogen ion and hydroxide ion is produced by passing deionized water through a system comprising an ultrafiltration step, an oxidizing step where water is exposed to ultraviolet light and ion exchange step. The treated water is recirculated through the oxidizing step and the ion exchange step. Product water from the system can be recovered on a continuous basis so long as the ratio of volume of water circulated within the system to volume of water drawn from the system is at least 10 and preferably at least 20.

Water purification process

An electrodeionization apparatus is provided for removing ions from liquids. Liquid to be purified is passed through depleting compartments containing mixed anion and cation exchange resin beads while a second liquid is passed through concentrating compartments free of ion exchange resin beads. Ions, under influence of an electrical potential, pass from the depleting compartments into the concentrating compartments through ion permeable membranes. A spacer for each depleting compartment is provided which retains the beads within the compartment, promotes even flow through the compartment and prevents plugging of the compartment inlet by the beads and external foulants.

Growing community of inventors

Dracut, MA, United States of America

Kitty K Siu