Devices, systems, and methods for the electrochemical generation of base/acid and deionization of saline water

An electrochemical system for generating acid and base solutions, comprising:

• a capacitive electrode configured to sorb anions from an input liquid during charging;
• a cathode configured to perform a hydrogen evolution reaction (HER) to generate a basic solution and hydrogen gas during charging;
• a control system configured to alternately charge and discharge the capacitive electrode;
• and
• an anode configured to perform a hydrogen oxidation reaction (HOR) or oxygen evolution reaction (OER) during discharge, wherein acid is generated during discharge.

A zinc redox electrochemical system for generating acid and base solutions from a saline or brine feed, comprising:

• an anode configured to oxidize zinc metal to Zn²⁺ ions during a first operational mode;
• a cathode configured to perform a hydrogen evolution reaction (HER) to generate a basic solution during the first operational mode;
• a zinc ion solution in contact with the anode;
• an ion-exchange membrane separating the anode and cathode compartments;
• and
• a second operational mode in which the polarity of anode and the cathode is reversed for zinc electrode replating, thereby reducing Zn²⁺ to zinc metal, generating an acid solution, and optionally oxidizing hydrogen or performing oxygen evolution reaction at the anode.