TABLE OF CONTENTS Electrolysis is one method of synthesizing chemicals, on the basis of oxidation at the anode and reduction at the cathode. To prevent the mixing of anolyte with catholyte, a separator is used between the electrodes, and an ion exchange membrane is used when ion selectivity is required of the separator. Because electrolysis occurs only on the surface of the electrodes, many electrolyzers are necessary for large scale production. On the other hand, highly pure chemicals can be produced by electrolysis because catalysts and additives are never used in the syntheses.
Ion exchange membranes are widely used in electrolysis as ion selective separators not only to synthesize inorganic and organic chemicals, but also for other purposes such as treating waste solutions. Table 6.6 lists example applications of ion exchange membranes in electrolysis. The ion exchange membrane is exposed to both reductive and oxidative environments. As mentioned before, though the membrane is stable to reducing reagents, hydrocarbon type ion exchange membranes deteriorate and decompose with oxidizing reagents. A perfluorocarbon membrane is used in a strongly oxidative atmosphere.
| Example | Treatment |
|---|---|
| Synthesis of inorganic and organic reagents | Electrolysis of sodium chloride and potassium chloride to produce alkali metal hydroxides, chlorine and hydrogen gas, synthesis of hydrogen peroxide, [104] production of hydrogen gas by water electrolysis, [105] reduction of UO 2 2 ? to U 4+, [106] preparation of highly pure metal salt solution, [107] |
