Characteristics of different electrode materials


Graphite electrode: Graphite electrode is easily corrod […]

Graphite electrode: Graphite electrode is easily corroded, the main reasons are chemical corrosion and mechanical wear; when graphite is used as anode, due to anodic oxidation, graphite is oxidized to CO2 or CO, its crystal structure is destroyed and damaged; in electrodialysis device The loss of middle graphite electrode is mainly caused by mechanical action. Extreme water with high flow velocity has a strong scouring effect on graphite. On the other hand, the gas produced by electrode reaction has an impact on graphite, and electrochemical corrosion often causes graphite. Particles flake off pollute the water quality and even block the water channel; with the appearance of titanium coated ruthenium electrodes, graphite electrodes have been gradually eliminated.

Titanium-plated platinum electrode: The corrosion resistance is quite good, and it can be used under very harsh conditions, but platinum is expensive and has fewer resources, which limits its promotion in the country.

Titanium coated ruthenium electrode: It is a compound of ruthenium (Ru), iridium (Ir), and titanium (Ti) coated on the titanium substrate, and the mixed oxide is formed after high temperature treatment; due to ruthenium (Ru), iridium (Ir), The ionic radius of titanium (Ti) is very close, and the lattice structure and space group belong to the same type. Therefore, a solid solution of RuO2-IrO2-TiO2 can be formed in the co-oxidation of heat treatment. It has excellent corrosion resistance and is very suitable as an electrode material.



Stainless steel electrode: Generally speaking, stainless steel is only used as a cathode and cannot be used as an anode. Otherwise, because natural water contains chloride ions, it will cause the anode of stainless steel to dissolve and generate divalent iron, nickel and chromium ions.

The correct choice of electrode material is of great significance for extending the service life of the electrode, reducing system investment and operating costs. For different water quality, you can choose electrodes of different materials:

1. For natural water with chloride as the main component, titanium-coated ruthenium electrodes are preferred.

2. For natural water with sulfate as the main component, lead plates, stainless steel, and titanium coated ruthenium electrodes are preferred.

3. For natural water with bicarbonate as the main component, stainless steel and titanium coated ruthenium electrodes are preferred.

4. For natural water with mixed ions, titanium-coated ruthenium, graphite and titanium-coated platinum electrodes are preferred.