8613480627251As the scale of industrial production continues to expand, the treatment of industrial wastewater containing recalcitrant organic compounds faces increasingly stringent requirements. Traditional biochemical treatment processes often exhibit limited efficacy in removing certain complex organic pollutants. In contrast, electrochemical advanced oxidation technologies—characterized by flexible reaction conditions and robust oxidizing capabilities—are increasingly being applied to the advanced treatment of industrial wastewater. Within these systems, electrolytic titanium electrodes (also known as Dimensionally Stable Anodes, or DSA) serve as critical components; their material structure and surface coatings directly dictate treatment efficiency and operational stability.
I. Titanium Substrates and Noble Metal Oxide Coatings
Electrolytic titanium electrodes typically utilize commercially pure titanium—most commonly grades Gr1 or Gr2—as a substrate. Titanium offers excellent mechanical strength and corrosion resistance, providing a stable structural foundation for the electrode.
Functional coatings are applied to the surface of the titanium substrate, often via processes such as thermal decomposition. Common coating materials include ruthenium dioxide, iridium dioxide, platinum, tantalum pentoxide, and tin dioxide; alternatively, mixed metal oxide (MMO) systems can be employed depending on specific application requirements.
The coating is essential for the electrode’s electrocatalytic function; it enhances surface reactivity and electrical conductivity, while also modulating the competition between the oxygen evolution reaction and the oxidation of organic compounds. An optimized coating formulation helps reduce operating voltage and improves current utilization efficiency.
II. Electrocatalytic Oxidation for the Degradation of Organic Pollutants
In the context of industrial wastewater treatment, electrolytic titanium electrodes facilitate the degradation of pollutants through two primary pathways: direct oxidation and indirect oxidation.
Upon the application of an electric current, electrochemical reactions occur at the anode surface, generating reactive oxygen species such as hydroxyl radicals. These reactive species interact with organic pollutants present in the wastewater, breaking down their molecular structures. This process gradually converts complex organic compounds into smaller molecules, with some pollutants undergoing complete mineralization into carbon dioxide and water. For organic wastewater that is difficult to treat via conventional biochemical processes, electrocatalytic oxidation can serve as a pre-treatment or advanced treatment stage. It helps reduce chemical oxygen demand (COD) and, under appropriate conditions, improves the biodegradability of the wastewater, thereby facilitating subsequent biochemical treatment.
III. Dimensional Stability and Long-term Operational Advantages
Compared to some traditional electrode materials, titanium-based dimensionally stable anodes (DSAs) offer superior structural stability and enhanced corrosion resistance. Under optimal operating conditions, the titanium substrate maintains its shape, while the functional surface coating provides sustained electrocatalytic activity.
This helps minimize equipment maintenance and downtime that would otherwise result from electrode deformation or rapid performance degradation. Nevertheless, the service life of an electrode is influenced by factors such as the coating system, current density, electrolyte composition, and operating temperature; therefore, selection and maintenance must be tailored to specific operational conditions.
Conclusion: By leveraging the structural advantages of a titanium substrate and the electrocatalytic properties of a noble metal oxide coating, titanium-based electrolytic electrodes are highly valuable for the advanced oxidation treatment of industrial wastewater. Actual COD removal efficiency, energy consumption, and service life should be evaluated comprehensively based on influent water quality, electrode type, reactor design, and operational parameters.
