Effect of Cathode Electrode Material and Voltage on the Production of Hydrogen Gas through the Chlor-Alkali Electrolysis Process of Brine Solution

Abstract

Hydrogen gas production is considered a highly promising technique in the field of sustainable and eco-friendly energy sources. The process of using a membrane to electrolyze brine is a vital approach for the creation of H₂ gas, Cl₂ gas, and NaOH. The corrosion resistance of the cathode electrode material and the contaminants present in the brine are the key determinants that impact this process. This study utilized cathode electrodes made from a variety of materials, including AlSI 304 and AlSI 316L stainless steel, with graphite as an anode electrode. Iraq’s Al-Basra salt resources, specifically the Al-Fao saltern, provided the brine for this study. The electrodes were subjected to different voltages of 4, 6, and 12 volts for duration of three hours. The salt impurities underwent NaOH treatment at a temperature of 80°C in order to induce precipitation as solid hydroxides, which were then filtered by an air vacuum device. The results indicated that the 304 stainless steel electrodes exhibit stability under low voltages but have diminished hydrogen emission via the cathode electrode. However, at higher voltages, the AlSI 304 electrode experiences significant pitting corrosion. This study clearly showed that when operating at voltages of 6 and 12 V, the AlSI 316L cathode electrode is best suited as the electrode material, which does not suffer from pitting corrosion. Graphite is the optimal material for an anode electrode. Through the research, a membrane system was created using locally available and inexpensive components. This system proved to be effective in producing the previous materials, especially sodium hydroxide, with a purity level of 40.50%. Additionally, the salt purification procedure successfully produced high recovery rates of 68.77% for magnesium hydroxide and 49.89% for calcium hydroxide, enabling their utilization in various industrial sectors.