Titanium anodes in wastewater treatment Removal of COD and practice
Explore how titanium anode technology can efficiently remove chemical oxygen demand from wastewater, providing innovative solutions for environmental protection and water quality improvement.
The environmental significance of COD (Chemical Oxygen Demand)
Among the numerous indicators used for water quality monitoring, Chemical Oxygen Demand (COD) represents the total amount of reducing substances in the water, with organic matter being the predominant component. The decomposition of organic matter in water consumes a large amount of oxygen, leading to a rapid decrease in dissolved oxygen levels. This disruption of the aquatic ecosystem results in deteriorating water quality – the water becomes dark and smelly, and once-clear rivers become turbid. As a result, biodiversity suffers a significant decline.
Technical Positioning of Titanium Anodes
In the treatment of high COD wastewater, titanium anodes, as the core component of electrochemical treatment technology, play an irreplaceable and crucial role, capable of accelerating the degradation process of organic matter in wastewater.
Structurally, titanium anodes use titanium metal as the substrate. Its light weight, high strength, and excellent corrosion resistance enable it to work stably in complex wastewater environments.
On the surface of the titanium substrate, a coating of precious metal oxides such as iridium and ruthenium is applied through a thermal decomposition oxidation process. This coating is the core where the titanium anode exerts its electrocatalytic activity.
The principle of action of titanium anodes in removing COD
Microscopic Mechanism Analysis of Electrocatalytic Oxidation
Direct electrochemical oxidation
In the microscopic world of electrochemical wastewater treatment, titanium anodes dominate the crucial process of direct electrochemical oxidation. When an electric current passes through the titanium anode, organic molecules in the wastewater undergo electron transfer on the surface of the titanium anode.
Take benzene ring aromatic compounds as an example; their stable conjugated systems are extremely difficult to decompose in the natural environment. However, under the strong electrocatalytic effect of the titanium anode, these stubborn organic molecules break their originally stable chemical bonds.
The C-C bonds on the benzene ring gradually break, and various functional groups in the molecules undergo oxidation reactions, ultimately converting the organic matter into simple, harmless small molecular substances, fundamentally reducing the COD value in the wastewater.
Indirect electrochemical oxidation
Titanium anodes provide a powerful boost to the removal of COD through indirect electrochemical oxidation, with the key to this process lying in the generation of free radicals. When an electric current passes through the titanium anode, the catalytic coating on its surface promotes the electrolysis of water molecules, generating a series of free radicals with strong oxidizing properties.
Among them, the most active is the hydroxyl radical (・OH), which has an oxidation potential of up to 2.8V, second only to fluorine gas, making it one of the most oxidizing substances in nature. In addition, strong oxidants such as ozone (O₃) are also generated during this process.Once these free radicals are generated, they initiate chain reactions in the wastewater, gradually oxidizing and decomposing pollutants, which are ultimately converted into harmless carbon dioxide, water, and inorganic salts, significantly improving the efficiency of COD removal from wastewater.
Titanium anodes, with their high efficiency, stability, and environmental friendliness, have become one of the core technologies for removing COD from wastewater. With the continuous advances in materials science and electrochemical engineering, the applications of titanium anodes will continue to expand, providing more sustainable solutions for improving the quality of industrial wastewater, reusing municipal sewage, and managing emerging pollutants.
