Electrochemical device for creation of pH gradients

1. A membraneless electrochemical device, comprising:

a fluid feed stream input to the membraneless electrochemical device;

a first electrode comprising a first redox-active material configured to have a proton-coupled oxidation reaction with a first portion of the fluid feed stream;

a second electrode comprising a second redox-active material configured to have a proton-coupled reduction reaction with a second portion of the fluid feed stream, wherein the first portion and the second portion are separated;

a first effluent stream comprising the first portion and having a first pH, wherein the first pH is the pH value of the first effluent stream;

a second effluent stream comprising the second portion and having a second pH different from the first pH, wherein the second pH is the pH value of the second effluent stream;

a first receptacle configured to receive an effluent stream having the first pH;

a second receptacle configured to receive an effluent stream having the second pH; and

a switching valve coupled to the first and second effluent streams and the first and second receptacles.

2. The membraneless electrochemical device of claim 1 , wherein at least one of the first and second redox-active materials is coated on at least one of the first or second electrodes.

3. The membraneless electrochemical device of claim 1 , wherein at least one of the first and second redox-active materials is a polymer grafted onto at least one of the first or second electrodes.

4. The membraneless electrochemical device of claim 1 , wherein the first redox-active material and the second redox-active material are the same.

5. The membraneless electrochemical device of claim 1 , wherein at least one of the first and second redox-active materials is at least one of a quinone, a phenazine, a pyrazine, a quinoxaline, and a derivative thereof, or at least one of the first and second redox-active materials is at least one of an ionomer and a polymer, wherein the at least one of the ionomer and polymer comprises at least one of a quinone, a phenazine, a pyrazine, a quinoxaline, and a derivative thereof.

6. The membraneless electrochemical device of claim 1 , wherein each of the first and second electrodes comprises at least one of a conductive material, a binder, and a conductive binder.

7. The membraneless electrochemical device of claim 1 , wherein the fluid feed stream flows parallel to a first surface of the first electrode and to a first surface of the second electrode, wherein the first surfaces face each other and are separated by a gap of a predetermined distance.

8. The membraneless electrochemical device of claim 1 , wherein the first and second electrodes are porous and positioned opposing each other and the first portion of the fluid feed stream flows through the first electrode and the second portion of the fluid feed stream flows through the second electrode.

9. The membraneless electrochemical device of claim 1 , wherein the first and second electrodes are porous.

10. The membraneless electrochemical device of claim 1 , wherein the first and second electrodes are coupled to an energy source configured to drive the proton-coupled oxidation reaction with the first redox-active material and the proton-coupled reduction reaction with the second redox-active material when an electrical potential is applied across the first and second electrodes, and configured to drive a proton-coupled reduction reaction with the first redox-active material and a proton-coupled oxidation reaction with the second redox-active material when the electrical potential applied across the first and second electrodes is reversed so that the first effluent stream has the second pH, wherein the second pH is the pH value of the second effluent stream before the electrical potential applied across the first and the second electrodes is reversed, and the second effluent stream has the first pH, wherein the first pH is the pH value of the first effluent stream before the electrical potential applied across the first and the second electrodes is reversed.

11. The membraneless electrochemical device of claim 1 , wherein the fluid feed stream comprises a target component.

12. The membraneless electrochemical device of claim 11 , wherein the target component is carbon dioxide.

13. The membraneless electrochemical device of claim 11 , wherein the target component is a salt.

14. A system comprising:

a fluid feed stream;

a membraneless electrochemical device, comprising:

a first electrode comprising a first redox-active material configured to have a proton-coupled oxidation reaction with a first portion of the fluid feed stream in response to a first electrical potential across the first electrode and a second electrode;

the second electrode comprising a second redox-active material configured to have a proton-coupled reduction reaction with a second portion of the fluid feed stream in response to the first electrical potential, wherein the first portion and the second portion are separated;

a first effluent stream comprising the first portion and having a first pH, wherein the first pH is the pH value of the first effluent stream;

a second effluent stream comprising the second portion and having a second pH different from the first pH, wherein the second pH is the pH value of the second effluent stream;

an energy source configured to apply the first electrical potential and a second, reverse electrical potential across the first and second electrodes;

a first receptacle configured to receive an effluent stream having the first pH;

a second receptacle configured to receive an effluent stream having the second pH; and

a switching valve coupled to the first and second effluent streams and the first and second receptacles.

15. The system of claim 14 , wherein the first receptacle comprises a base material configured to react with the effluent stream having the first pH to increase the pH of the effluent stream to a third pH before the effluent stream is discharged.

16. The system of claim 14 , wherein the fluid feed stream comprises a target molecule or solute and the first receptacle comprises a base material configured to react with the effluent stream having the first pH to separate the target molecule or solute before the effluent stream is discharged.

17. The system of claim 14 , wherein the second effluent stream is processed to absorb and capture carbon dioxide by reacting the second effluent stream with carbon dioxide.

18. The system of claim 14 , wherein the switching valve is configured to direct the first effluent stream to the first receptacle and the second effluent stream to the second receptacle when the energy source applies the first electrical potential across the first and second electrodes, and is configured to direct the second effluent stream to the first receptacle and the first effluent stream to the second receptacle when the energy source applies the second, reverse electrical potential across the first and second electrodes.

19. The system of claim 14 , wherein the fluid feed stream flows parallel to a first surface of the first electrode in the membraneless electrochemical device and parallel to a first surface of the second electrode in the membraneless electrochemical device, wherein the first surfaces face each other and are separated by a gap of a predetermined distance.

20. The system of claim 14 , wherein the first and second electrodes of the membraneless electrochemical device are porous and the first portion of the fluid feed stream flows through the first electrode and the second portion of the fluid feed stream flows through the second electrode.