An electrically regeneratable battery of electrochemical cells for
capacitive deionization (including electrochemical purification) and
regeneration of electrodes is operated at alternate polarities during
consecutive cycles. In other words, after each regeneration step operated
at a given polarity in a deionization-regeneration cycle, the polarity of
the deionization step in the next cycle is maintained. In one embodiment,
two end electrodes are arranged one at each end of the battery, adjacent
to end plates. An insulator layer is interposed between each end plate
and the adjacent end electrode. Each end electrode includes a single
sheet of conductive material having a high specific surface area and
sorption capacity, preferably a sheet formed of carbon aerogel composite.
The batter further includes a plurality of generally identical
double-sided intermediate electrodes that are equidistally separated from
each other, between the two end electrodes. As the electrolyte enters the
battery of ells, t flows through a continuous open serpentine channel
defined by the electrodes, substantially parallel to the surfaces of the
electrodes. By polarizing the cells, ions are removed from the
electrolyte and are held in the electric double layers formed at the
carbon aerogel surfaces of the electrodes. As the electrodes of each cell
of the battery are saturated with the removed ions, the battery is
regenerated electrically at a reversed polarity from that during the
deionization step of the cycle, thus significantly minimizing secondary
wastes.