Abstract: An electrochemical method for the production of a chlorine-based oxidant product, such as sodium hypochlorite, is disclosed. The method may potentially be used to produce sodium hypochlorite from sea water or low purity un-softened or NaCl-based salt solutions. The method utilizes alkali cation-conductive ceramic membranes, such as membranes based on NaSICON-type materials, and organic polymer membranes in electrochemical cells to produce sodium hypochlorite. Generally, the electrochemical cell includes three compartments and the first compartment contains an anolyte having an acidic pH.