How does the corrosion resistance of titanium anodes work in seawater desalination?

The corrosion resistance of titanium anodes is mainly reflected in the following aspects in seawater desalination:

Seawater contains a large amount of chloride ions, which are highly corrosive to ordinary metallic materials. The dense oxide film (such as TiO₂) formed on the surface of titanium anodes can effectively block the erosion of chloride ions. Even in seawater with high chloride ion concentrations, they can maintain stable performance and will not corrode or dissolve as quickly as other materials.

Titanium anodes can dynamically form a self - healing oxide film in seawater, which is only 2 - 7 nanometers thick but has extremely high stability and self - healing ability. This oxide film can effectively isolate the direct contact between the electrolyte and the titanium substrate, significantly reducing the corrosion rate. For example, in boiling hydrochloric acid at 80℃, the corrosion rate of titanium is only 1/200 that of stainless steel.

Titanium materials exhibit high resistance to crevice corrosion and microbiologically influenced corrosion (MIC) in seawater. Crevice corrosion is a common form of corrosion for many metals in seawater environments. However, due to the stability of the oxide film on its surface, titanium anodes can effectively avoid crevice corrosion even under low pH or stagnant conditions. In addition, titanium has low toxicity to microorganisms and will not suffer from microbiologically influenced corrosion in still seawater.

The corrosion resistance of titanium anodes enables them to operate stably at high current densities, thereby significantly improving electrolysis efficiency and reducing energy consumption. For example, in the process of seawater desalination, the specific energy consumption for water production in a system using titanium anodes can be reduced from 4.8 kWh/m³ to 4.3 kWh/m³.

The corrosion resistance of titanium anodes gives them a long service life in seawater desalination equipment, typically lasting 5 - 7 years. In contrast, traditional materials such as graphite anodes have a shorter service life and need to be replaced frequently. The long - term service life of titanium anodes not only reduces the maintenance cost of the equipment but also reduces the downtime caused by anode replacement.

The stable coating of titanium anodes will not release impurities during the electrolysis process, thereby avoiding the pollution of the freshwater and electrolyte produced in the seawater desalination process. This is of great significance for ensuring the quality of desalinated water and reducing environmental pollution.

Titanium anodes, with their excellent corrosion resistance, not only operate efficiently and stably in seawater desalination but also reduce energy consumption and maintenance costs. They are an indispensable key material in the field of seawater desalination.