Working Principle of MMO Titanium Electrodes in Water Treatment

With the continuous development of industrial wastewater treatment and electrochemical oxidation technologies, MMO titanium electrodes, with their strong corrosion resistance, stable catalytic coating, high current efficiency, and long service life, are widely used in wastewater treatment, water disinfection, seawater electrolysis, and industrial electrolysis.

What is an MMO Titanium Electrode?

An MMO titanium electrode is a size-stabilized anode (DSA) made by coating a titanium substrate with a mixture of metal oxides. The titanium substrate has high mechanical strength and corrosion resistance, while the catalytic coating enhances the electrochemical reactions in the water treatment process.

Commonly used coating materials include:

Ruthenium oxide (RuO₂)

Iridium oxide (IrO₂)

Tantalum oxide (Ta₂O₅)

Platinum (Pt)

Different coating formulations are selected based on the electrochemical reaction requirements and electrolyte composition.

MMO titanium electrodes have various structures, including:

Titanium mesh electrode

Titanium plate electrode

Titanium tube electrode

Titanium rod electrode

The stable electrochemical performance of these electrodes makes them widely used in industrial electrolysis systems.

Working Principle of MMO Titanium Electrode

Electrochemical Reaction Mechanism

In water treatment systems, the MMO titanium electrode serves as the anode of an electrochemical cell. During electrolysis, current flows through the electrolyte, triggering redox reactions.

The MMO coating exhibits high catalytic activity, enhancing the efficiency of the electrochemical reaction.

Main reactions include:

Oxygen Evolution Reaction (OER)

On the anode surface, water molecules are oxidized to produce oxygen:

2H₂O → O₂ + 4H₂ + 4e⁻

This creates strong oxidizing conditions, aiding in the degradation of organic pollutants in wastewater.

Chlorine Evolution Reaction (CER)

In chlorinated wastewater, chloride ions can be oxidized:

2Cl⁻ → Cl₂ + 2e⁻

The generated chloride and hypochlorite ions possess disinfection and oxidizing capabilities.

The Role of Hybrid Metal Oxide Coatings

Main functions include:

Reducing oxygen evolution overpotential

Improving current efficiency

Enhancing electrochemical catalytic activity

Reducing energy consumption

Extending electrode lifespan

The catalytic coating accelerates electron transfer during electrolysis, making the water treatment process more efficient and stable.

Compared to traditional electrodes, MMO titanium electrodes achieve the same treatment efficiency with a lower operating voltage.

Titanium as the substrate

Corrosion Resistance

Titanium forms a stable oxide film on its surface, effectively resisting corrosion from acidic, alkaline, and chlorine-containing environments.

High Mechanical Strength

Titanium maintains structural stability during long-term industrial operation.

Good Electrical Conductivity

The titanium substrate ensures effective current distribution during electrolysis.

Strong Coating Adhesion

The MMO coating bonds firmly to the titanium surface, improving durability and operational stability.

Electrochemical Oxidation Process in Water Treatment

Electrochemical oxidation is one application of MMO titanium electrodes.

During the treatment process:

Contaminants diffuse to the electrode surface.

Oxidation reactions occur on the MMO catalyst layer.

Organic compounds decompose into smaller molecules.

Harmful substances are mineralized into carbon dioxide and water.

Effectively removes:

Chemical Oxygen Demand (COD)

Ammonia Nitrogen

Organic Pollutants

Dyes
Phenolics

Bacteria and Viruses

Electrochemical oxidation technology is used to treat recalcitrant industrial wastewater.

Advantages of MMO Titanium Electrodes in Water Treatment

High Current Efficiency

The MMO coating improves electron transfer efficiency and reduces energy loss during electrolysis.

Long Service Life

The stable catalytic coating allows for continuous operation under harsh industrial conditions.

Service life: 2-5 years

Depending on operating conditions.

Low Energy Consumption

Reduced electrochemical overpotential lowers energy consumption in water treatment processes.

Strong Corrosion Resistance

MMO titanium electrodes operate in acidic, alkaline, and saline environments.

Environmentally Friendly Technology

Electrochemical water treatment reduces the use of chemical additives and lowers secondary pollution.

Applications of MMO Titanium Electrodes

Industrial Wastewater Treatment:

Removal of Chemical Oxygen Demand (COD)

Heavy Metal Wastewater Treatment

Chemical Wastewater Purification

Municipal Wastewater Treatment

Electrochemical oxidation systems for wastewater purification and disinfection.

Electroplating Wastewater Treatment

Effectively removes metal ions and organic pollutants from electroplating wastewater.

Seawater Electrolysis

Used in seawater disinfection and chlorine generation systems.

Drinking Water Disinfection

Disinfectant is generated through an electrochemical reaction.

Factors Affecting Electrode Performance

Several factors affect the efficiency and lifespan of MMO titanium electrodes.

Current Density

Higher current densities can increase processing efficiency but accelerate coating wear.

Operating Range: 500–8000 A/m²

Electrolyte Composition

Chloride ion concentration, pH value, and organic contaminants can affect the electrochemical reaction.

Operating Temperature

Excessively high temperatures may reduce coating stability and shorten electrode life.

Recommended operating temperature is generally below: 85°C

Coating Formulation

Different coating systems are suitable for different electrochemical environments.

For example:

Ru-Ir coating for chlorine evolution reaction

Ir-Ta coating for oxygen evolution reaction

Comparison with Traditional Electrodes

Compared to graphite electrodes, MMO titanium electrodes offer the following advantages:

Long service life

Strong corrosion resistance

Low maintenance costs

High electrochemical efficiency

Stable performance

Compared to lead dioxide electrodes, MMO titanium electrodes are environmentally friendly and suitable for industrial applications.

The high catalytic activity, corrosion resistance, and long service life of MMO titanium electrodes make them the preferred choice for industrial wastewater treatment, water disinfection, and electrolysis applications.

Frequently Asked Questions

What are the main functions of MMO titanium electrodes in water treatment?

MMO titanium electrodes promote electrochemical oxidation reactions, removing contaminants and disinfecting water.

Why are MMO titanium electrodes better than graphite electrodes?

They offer long service life, strong corrosion resistance, and high electrochemical efficiency.

What coating is typically used for the oxygen evolution reaction (OER)?

Iridium-tantalum coating is a commonly used coating for the OER.

Can MMO titanium electrodes be customized?

Yes. We can provide customized sizes, structures, and coating systems to meet the needs of different industrial applications.

Which industries use MMO titanium electrodes?

Application industries include wastewater treatment, electroplating, chemical processing, hydrogen production, and seawater electrolysis.

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