Microelectrolysis technology, also known as internal electrolysis, is an ideal process for treating high-concentration organic wastewater. It utilizes microelectrolysis materials filled in the wastewater to generate a self-generated potential difference of 1.2V without external power supply, electrolyzing the wastewater to degrade organic pollutants. Once the system is filled with water, numerous microcell systems are formed within the equipment, creating an electric field in their working space.
During the treatment process, newly generated species such as [H] and Fe2+ undergo oxidation-reduction reactions with various components in the wastewater. For example, they can destroy chromophoric groups or assisting chromophoric groups in colored wastewater, even causing chain breaks, leading to degradation and decolorization. The generated Fe2+ further oxidizes to Fe3+, and their hydrates exhibit strong adsorption-coagulation activity. Particularly, after adjusting the pH value with alkali, the formation of ferrous hydroxide and ferric hydroxide colloidal coagulants greatly enhances their adsorption capacity, surpassing the hydroxide iron colloid obtained by general chemical agent hydrolysis, and enabling the adsorption of dispersed particles, metal particles, and organic macromolecules in water. The working principle of this technology is based on the combined effects of electrochemistry, oxidation-reduction, physical adsorption, and coagulation-precipitation for wastewater treatment.
This method has the advantages of wide applicability, good treatment effect, low cost, easy operation and maintenance, and no consumption of electrical resources. When applied to the treatment of refractory high-concentration wastewater, it can significantly reduce COD and color, improve the biodegradability of the wastewater, and effectively remove ammonia nitrogen. In the past, the microelectrolysis process typically used iron shavings and charcoal as microelectrolysis materials, which required acid-base activation before use and were prone to passivation and agglomeration during the process. Furthermore, due to the physical contact between iron and charcoal, an isolation layer easily formed between them, rendering the microelectrolysis ineffective and necessitating frequent replacement of the microelectrolysis materials. This not only increased the workload and cost but also affected the efficiency and effectiveness of wastewater treatment. Additionally, the small surface area of traditional microelectrolysis materials resulted in a prolonged treatment time, increasing the investment cost per unit of water and severely impacting the utilization and promotion of microelectrolysis technology.