Electrochemical process for gas separation

A method of treating a gas stream, the method comprising:

• applying a first potential difference across an electrochemical cell, thereby causing a first electroactive species to be in a reduced state, the electrochemical cell comprising:
• at least one porous negative electrode comprising the first electroactive species;
• a positive electrode comprising a second electroactive species;
• and
• a separator positioned between the at least one porous negative electrode and the positive electrode;
• introducing a gas stream comprising a target species comprising an aprotic acidic gas to the electrochemical cell to bond the target species to the first electroactive species in the reduced state to produce a treated gas stream;
• and
• applying a second potential difference across the electrochemical cell, thereby causing the first electroactive species to be in an oxidized state, to release the target species from the first electroactive species in the oxidized state to produce a target species-rich gas stream;
• wherein:
• the first electroactive species comprises polyanthraquinone, a thiolate, a bipyridine, or a combination thereof, and
• the second electroactive species has a reduction potential at least 0.5 Volts more positive than a first reduction potential of the first electroactive species.