Titanium Anode For Swimming Pool

Swimming pool water safety is a core prerequisite for ensuring swimmers’ health. Disinfection technology is crucial for maintaining water quality standards. Traditional pool disinfection relies on the manual addition of chemical agents such as chlorine preparations and chlorine tablets. While this can temporarily kill microorganisms, it presents numerous challenges. Inaccurate dosing can lead to fluctuating residual chlorine concentrations. High concentrations can cause skin irritation, red eye, and other discomfort, while low concentrations can provide ineffective protection. Chemicals react with organic matter in the water to produce carcinogenic byproducts such as chloroform, which accumulate over time and pose a threat to human health.

With the advancement of materials science and electrochemical technology, MMO titanium anode (titanium-based metal oxide-coated electrode) has become a technological breakthrough in pool disinfection due to its revolutionary performance advantages. This novel electrode material, based on a titanium matrix and coated with precious metal oxides such as ruthenium and iridium, achieves a closed-loop purification model of “on-demand disinfectant production” through the electrolysis of brine, fundamentally changing the traditional chemical-based disinfection model. From small family pools to Olympic-sized competition pools, from hot spring spas to large water parks, MMO titanium anodes are becoming core components of high-end pool water treatment systems.

Working Principle of the MMO Titanium Anode

The core function of the MMO titanium anode in swimming pools is to generate a highly effective disinfectant through an electrolytic reaction. Its operating mechanism is based on precisely controlled electrochemistry.

(I) Core Electrolytic Reaction

The disinfection function of the MMO titanium anode relies on the targeted conversion of chloride ions in the pool water. In practical applications, an appropriate amount of salt (sodium chloride) is first added to the pool water to maintain the salt concentration within the optimal range of 3%-5%. The water then flows through the electrolytic cell equipped with the MMO titanium anode. The electrodes and the DC electric field trigger two key reactions:

Anodic Chlorine Evolution Reaction: Under the catalytic action of the ruthenium-iridium oxide coating, chloride ions (Cl⁻) in the anode region lose electrons and are oxidized to chlorine gas (Cl₂). The reaction equation is: 2Cl⁻ → Cl₂↑ + 2e⁻. This reaction requires a startup voltage of only 1.13V, resulting in extremely low energy consumption. The coating’s high catalytic activity ensures the directional nature of the reaction, preventing ineffective side reactions.

Disinfectant Generation Reaction: The generated chlorine gas rapidly hydrolyzes with water, converting to highly oxidizing hypochlorous acid (HClO) via the reaction equation: Cl₂ + H₂O → HClO + H⁺ + Cl⁻. Hypochlorous acid has a redox potential of 650-800mV, making it over 80 times more effective at killing bacteria than traditional chlorine agents, effectively killing 99.99% of common pathogens such as Escherichia coli and Pseudomonas aeruginosa within 30 seconds.

Notably, after completing its bactericidal action, the hypochlorous acid generated in this process decomposes back into chloride ions and returns to the water, forming a closed “salt-disinfectant-salt” cycle that leaves no permanent chemical residue.

(II) Material Enhancement and Protection

The superior performance of the MMO titanium anode stems from its unique material structure design. Through optimized substrate pretreatment and coating processes, electrolysis efficiency and equipment life are significantly improved:

Micro-arc oxidation pretreatment: The titanium substrate surface undergoes 20,000V high-voltage micro-arc oxidation treatment, creating a nanoscale honeycomb-like porous structure that triples the electrode’s active area. This increases electrolysis efficiency to 95.2%, ensuring the disinfectant production rate meets the needs of pool water circulation.

Gradient coating protection: Utilizing a three-layer structure of “tantalum metal base layer + tantalum oxide transition layer + iridium ruthenium oxide top layer,” this effectively mitigates the thermal expansion difference between the titanium substrate and the coating, resulting in a coating shedding rate of less than 0.5%. This structure ensures the anode remains stable in extreme swimming pool environments with high chloride ion concentrations and a pH range of 2-12, completely eliminating the corrosion and coating peeling issues associated with traditional stainless steel electrodes.

(3) Intelligent System Collaboration Mechanism

The modern MMO titanium anode swimming pool system has achieved deep integration with IoT technology, forming a dynamic closed-loop control system. By integrating pH/ORP sensors to monitor water quality parameters in real time, the system automatically adjusts the electrolysis current density and salt dosage to precisely stabilize the residual chlorine concentration within a safe range of 0.3-0.5ppm—far lower than the 1-3ppm standard for traditional swimming pools. This ensures effective disinfection while avoiding skin irritation and other discomfort.

MMO Titanium Anode Types

MMO titanium anodes suitable for swimming pools can be categorized into different types based on coating composition, structural morphology, and application scenarios. Each product has its own advantages in catalytic properties and applicable operating conditions, requiring precise selection based on the pool size and water quality. The coating material directly determines the anode’s catalytic performance. Mainstream MMO titanium anodes for swimming pools fall into the following two categories.

Ruthenium MMO Titanium Anodes

Using a core coating of ruthenium-iridium mixed oxide, these are typical chlorine-evolving electrodes. Their key advantage is their highly selective oxidation of chloride ions, enabling efficient chlorine gas production at low voltages, achieving disinfectant conversion efficiencies exceeding 95%, and offering outstanding resistance to chlorine corrosion. This type of anode perfectly meets the core requirements of pool salt electrolysis disinfection and is a popular choice for home pools, hotel pools, and water parks.

Iridium MMO Titanium Anodes

Using an iridium-tantalum oxide as the primary coating, they exhibit dual oxygen and chlorine evolution activities. Compared to ruthenium-based anodes, they offer greater resistance to acid and alkali corrosion and perform more stably in complex water environments, such as hot spring pools and pools with naturally occurring mineral-rich water sources. While their chlorine evolution efficiency is slightly lower than that of ruthenium-based products, they can withstand conditions with greater pH fluctuations and are suitable for high-end pools requiring high water compatibility.

Also, while platinum-titanium anodes can be used for pool disinfection, their high cost limits their limited use in specialized applications requiring extreme water purity, such as medical and rehabilitation pools, and they are not a mainstream choice in the industry.

Titanium Plate Anodes

Made from pure titanium plates that are pre-treated and then coated with an MMO coating, they offer a compact design and easy installation, making them suitable for small and medium-sized home pools or spas. The surface coating thickness is typically controlled at 8-10 microns, ensuring uniform current conduction. Modular assembly allows for adaptability to varying water volume requirements.

Titanium Tube Anodes

Using a titanium tube as the substrate, the coating evenly covers the inner and outer surfaces of the tube, resulting in a large surface area and high electrolysis efficiency. This type of anode is suitable for centralized disinfection systems in medium- to large-sized swimming pools. It can be directly integrated with piped water circulation systems, performing electrolytic disinfection as water flows through the titanium tubes, eliminating the need for additional equipment space. In seawater pools, titanium tube anodes can also perform both disinfection and anti-scaling functions.

Titanium Strip Anodes

These have a ribbon-like structure and can be flexibly tailored to the size of the electrolytic cell, adapting to custom-shaped or customized disinfection equipment. Their advantage lies in uniform current distribution, effectively preventing water quality fluctuations caused by localized over-electrolysis. They are often used in high-end hotel pool disinfection systems.

Small Home Anode Systems

These typically utilize modular titanium plate anodes with low power consumption (typically less than 500W). They feature integrated automatic salinity monitoring and are easy to operate, making them suitable for home pools measuring 10-50m³.

Medium-Sized Commercial Anode Systems

These typically utilize a combination of titanium tubes and plates, with power consumption ranging from 500W to 5kW, making them suitable for hotel and club pools measuring 50-500m³.

Large-Scale Project Anode System

Utilizing a titanium tube array design, it delivers power exceeding 5kW and is suitable for water parks, public swimming pools, and competition pools exceeding 500m³. The system supports parallel operation of multiple anode groups, dynamically adjusting disinfection power based on visitor flow.