Fig. 3.

Predictions and experimental results for an FTE CDI cell with feed salt concentration, $c_{\mathrm{F}}$, of 2 mM; feed boron concentration, $c_{\mathrm{F},\mathrm{B}}$, of 0.37 mM; and Pe = 3. Predictions in A–C are for charging voltage, $V_{\mathrm{c}\mathrm{h}}$, of 0.6 V (solid lines), 1.0 V (dashed lines), and 1.4 V (dotted lines). (A) Predicted pH (left y axis, black lines) and macropore salt concentration (right y axis, blue lines) profiles. (B) Predicted dimensionless potential (left y axis, black lines) and ${\mathrm{B}}^{-}$ macropore concentration (right y axis, blue lines) profiles. The profiles in A and B are for $t/{\tau }_D=2$, gray rectangles represent the separator, and the horizontal dash-dotted blue line in A represents feed salt concentration. (C and D) pH in the macropores as a function of dimensionless location and time for $V_{\mathrm{c}\mathrm{h}}$ of 0.6 V (C) and 1.4 V (D). The vertical dash-dotted lines in C and D represent the electrode/separator interfaces. (E) Predicted pH at the anode/separator (an/sep) interface (left y axis, black lines) and electrosorbed boron (right y axis, blue lines), both as a function of dimensionless time. (F) Predicted (line) and measured (markers) boron electrosorption for an effluent collection time of 10 min versus $V_{\mathrm{c}\mathrm{h}}$.