suolaelektrolyysissä

Suolaelektrolyysi, also known as electrolysis of brine, is a fundamental electrochemical process used to produce chlorine gas, hydrogen gas, and sodium hydroxide (caustic soda). This process involves passing an electric current through an aqueous solution of sodium chloride (NaCl), commonly known as brine.

The overall reaction can be summarized as: 2 NaCl(aq) + 2 H2O(l) → 2 NaOH(aq) + Cl2(g) + H2(g). At the anode (positive electrode), chloride ions are oxidized to form chlorine gas: 2 Cl⁻(aq) → Cl₂(g) + 2 e⁻. At the cathode (negative electrode), water molecules are reduced to form hydrogen gas and hydroxide ions: 2 H₂O(l) + 2 e⁻ → H₂(g) + 2 OH⁻(aq). The sodium ions (Na⁺) present in the solution combine with the newly formed hydroxide ions (OH⁻) to produce sodium hydroxide (NaOH).

There are three primary industrial methods for carrying out suolaelektrolyysi: the diaphragm cell process, the mercury cell process, and the membrane cell process. The diaphragm and membrane cell processes are more environmentally friendly and energy-efficient than the mercury cell process, which is being phased out due to mercury's toxicity.

Chlorine gas produced is a vital chemical used in the manufacturing of plastics (like PVC), solvents, disinfectants, and pharmaceuticals. Hydrogen gas has applications in ammonia production, hydrogenation of oils, and as a fuel. Sodium hydroxide is essential in the production of paper, textiles, soaps, detergents, and in various chemical processes. Therefore, suolaelektrolyysi is a cornerstone of the modern chemical industry, supplying several essential commodities.