Fig. 4.

Predictions for an FTE CDI cell with NaCl-containing feedwater (A–D) or NaCl and boron-containing feedwater (E and F) with charging voltage, $V_{\mathrm{c}\mathrm{h}}$, of 1.0 V. (A and B) Predicted pH (left y axes, black lines) and macropore salt concentration (right y axes, blue lines) profiles at $t/{\tau }_D=3$, where the gray rectangles represent the separator, and the horizontal dash-dotted blue line in A represents the feed salt concentration. (A and E) Results for $\mathrm{P}\mathrm{e}=0.2$ (solid lines), 1 (dashed lines), and 5 (dotted lines), all with feed salt concentration, $c_{\mathrm{F}}$, of 0.5 mM. (B and F) Results for $c_{\mathrm{F}}$ = 0.1 mM (solid lines), 0.5 mM (dashed lines), and 5 mM (dotted lines), all with Pe = 1. (C and D) Predicted pH at the anode/separator (an/sep) interface as a function of $c_{\mathrm{F}}$ and Pe at $t/{\tau }_{\mathrm{D}}=0.5$ (C) and $t/{\tau }_{\mathrm{D}}=3$ (D). (E and F) Predicted pH at the anode/separator interface (left y axes, black lines) and electrosorbed boron (right y axes, blue lines), both as a function of dimensionless time.