Large scale chlorine isolation for industrial purposes is isolated through the electrolysis of sodium chloride. Through this process, sodium chloride is dissolved in water and an electric current is passed through the solution. The resulting chemicals are elemental chlorine, hydrogen gas, and sodium hydroxide. Other isolation processes using electrolysis of chloride solutions include mercury cell electrolysis and diaphragm cell electrolysis.
Mercury cell electrolysis is the least inefficient of the chlorine isolation processes. During this process, titanium anodes are used in a sodium chloride, or potassium chloride, solution which flows over a liquid mercury cathode. The current flows releases chlorine, and the sodium, or potassium, element reacts with the mercury.
Diaphragm cell electrolysis uses an asbestos diaphragm to separate the cathode and anode. During this process the brine, or chlorine salt solution, is passed into the anode compartment and then flows through the asbestos diaphragm to the cathode compartment. Elemental chlorine forms in the anode compartment while sodium hydroxide and hydrogen form in the cathode compartment.
