An electrochemical device comprises an electrochemical cell. The electrochemical cell comprises a composite cation-exchange member including a conductive base and a cation-exchange material in physical contact with the conductive base, a composite anion-exchange member including a conductive base and an anion-exchange material in physical contact with the conductive base; and a compartment between the composite cation-exchange and anion-exchange members. The compartment comprises an inlet for introducing a feed stream, and an outlet for exiting of an output stream out of the compartment. The electrochemical device comprises a control device configured to transmit an electrical current to the composite cation-exchange and anion-exchange members at a regeneration stage in a manner that the conductive base on the composite cation-exchange member loses electrons and the conductive base on the composite anion-exchange member gains electrons.