Effect of DC Deep-Well Ground Electrode Materials on gas Evolution

The uniqueness of DC deep-well ground electrodes (DWGEs) lies in their low area requirements. However, the gas produced by DWGEs during electrolysis may cause more severe exhaust problems than those caused by conventional electrodes. To investigate the influence of different electrode materials on the gas evolution of DWGEs, an innovative U-shaped experimental platform is proposed for the separate collection of cathode and anode gases. The metal–electrolyte contact interface in a DWGE project was simulated, and gas evolution experiments were performed on three typical ground electrode materials. The gas evolution rates of the electrode materials when operate as cathodes and anodes were obtained. Polarization curves were used to compare the corrosion rates of the three materials and evaluate the effects of these rates on the gas evolution rates of the materials. The results revealed that when operated as anodes, mixed metal oxide (MMO) and high-silicon cast iron produced oxygen, whereas carbon steel did not. Furthermore, the evolution of O ₂ in MMO was faster than that in high-silicon cast iron. When operated as cathodes, the three materials generated hydrogen, and carbon steel exhibited the slowest H ₂ evolution rate. The current distribution in the different gas evolution processes was summarized. The supplied current was used as the reaction current of metal corrosion and for gas generation. Under the same current, quicker corrosion corresponded to a lower amount of gas evolution for a material.