Method of regenerating a capacitive deionization cell
View Patent ↗A method of operating a capacitive deionization cell using a regeneration cycle to increase pure flow rate and efficiency of the cell.
1. A method for efficiently softening water in a cell comprising a water inlet, a water outlet, a cathode current collector and an anode current collector, the method comprising:
during a charge cycle, creating a stream of clean water in a direction from the inlet to the outlet at a flow rate F1, while applying a charge voltage of between about 0.5V and about 1.3V between the cathode current collector and the anode current collector of a cell for a period of time T1;
during a discharge cycle, creating a stream of waste water in the direction from the inlet to the outlet at a flow rate F2, while applying a discharge voltage between about −1.3V and about −0.5 V between the cathode current collector and the anode current collector for a period of time T2;
repeating the charge and discharge cycles C times, wherein C>1; and
applying a regeneration voltage between 0.0 V and −1.3 V between the cathode current collector and the anode current collector to a stream of water in the direction from the inlet to the outlet at a flow rate F3, for a period of time T3 such that F1*T1*C/[F1*T1*C+F2*T2*C+F3*T3] is greater than or about equal to 0.7,
wherein T3 is greater than T2.
2. The method of claim 1 , wherein the cell further comprises (i) a spacer, (ii) a first electrode capable of absorbing ions, (iii) a second electrode capable of adsorbing ions, and (iv) a cation selective membrane, an anion selective membrane, or both.
3. The method of claim 1 , wherein T1 is 2 times T2.
4. The method of claim 1 , wherein T1 is 1 minute and T2 is 30 seconds.
5. The method of claim 1 , further comprising:
determining total dissolved solids in the clean water; and
controlling the charge and discharge cycles using the determined total dissolved solids.
6. The method of claim 5 , wherein determining total dissolved solids comprises utilizing a conductivity probe to analyze the clean water.
7. The method of claim 1 , wherein T1 is greater than T2.
8. The method of claim 1 , wherein the charge voltage is substantially equal to the discharge voltage.
9. The method of claim 1 , wherein C is greater than or equal to 3.