Nanobubble Ozone Technology – Advancing Mass Transfer Through Physics

As water treatment challenges grow more complex, driven by tighter regulations, emerging contaminants, and spatial constraints, utilities and engineers are exploring next-generation ozone delivery methods. Among these, nanobubble ozone technology has gained attention for its potential to increase mass transfer efficiency, extend ozone retention, and improve treatment of turbid or organic-rich waters.

But what exactly are ozone nanobubbles? Why does their electrical charge matter? And where do they truly outperform conventional injection systems?

At Pinnacle Ozone Solutions, we separate marketing from mechanics. This blog examines the underlying physics of ozone nanobubbles, their electrochemical behavior, and the real-world engineering implications for treatment systems.

What Is a Nanobubble?

Nanobubbles are gas bubbles with diameters typically <200 nanometers, 1,000 times smaller than conventional microbubbles.

Key properties:

• Invisible to the naked eye
• Neutrally buoyant or extremely slow to rise due to low terminal velocity
• Large surface-area-to-volume ratio ⇒ high interfacial transfer efficiency
• Persistent in water for hours or days without collapsing

The Role of Surface Charge (Zeta Potential)

One of the most unique and consequential features of nanobubbles is their electrical charge, typically measured as zeta potential (ζ). Due to interfacial interactions between the gas, water molecules, and ions, nanobubbles acquire a negative surface charge.

This electrostatic layer:

• Stabilizes the bubble against coalescence or collapse
• Prevents aggregation into larger bubbles
• Helps trap reactive oxygen species (ROS) near the interface
• In ozone applications, it may stabilize ozone molecules at the gas–liquid interface or promote localized radical generation

Reference: Ohgaki et al. (2010), Electrochemical Properties of Nanobubbles in Aqueous Systems

Zeta potential values for ozone nanobubbles have been measured in the range of –25 to –45 mV, depending on pH, ionic strength, and gas composition.

Ozone Behavior Inside and Around Nanobubbles

When ozone is used in nanobubble form, several unique phenomena may occur:

Delayed Ozone Collapse = Extended Half-Life

Nanobubbles resist collapse due to the repulsive electrostatic force from their surface charge and the internal pressure balance (Young–Laplace equation). As a result:

• Ozone persists longer in the aqueous phase, even at elevated temperature or low UVT
• Oxidation reactions can occur over longer time horizons and farther downstream

Enhanced Localized Oxidation

Ozone at the gas–liquid interface may react more efficiently with:

• Organics near bubble surfaces
• Iron, manganese, or sulfide ions that adsorb to charged surfaces
• Biofilms or particles attracted to the electrostatic field

There is also evidence that hydroxyl radicals (·OH) may form preferentially near the nanobubble interface under certain conditions (alkaline pH, NOM presence), enhancing advanced oxidation performance.

Reference: Takahashi et al. (2011), Nanobubbles and their Interaction with Water Contaminants

Improved Penetration in Biofilms and Fouling Layers

Due to their small size and electrostatic stabilization, nanobubbles may diffuse into porous or fouled zones where conventional ozone bubbles cannot reach—useful in:

• Cooling towers
• Membrane cleaning systems
• Biological filters
• High-turbidity or high-TSS applications

Mass Transfer Efficiency: How Nanobubbles Compare

The key benefit of ozone nanobubbles is higher ozone transfer efficiency at lower gas flow rates.

• Standard venturi or diffuser systems: 60–90% mass transfer
• Pressurized Pinnacle systems: 95–98% mass transfer
• Nanobubble ozone systems: report up to 99%+ under controlled conditions

However, mass transfer alone is not the full story, what matters is:

• How much ozone dissolves per kWh of energy
• How stable that dissolved ozone is
• What reactions it undergoes once transferred

This is where system design, water chemistry, and process integration become critical.

Applications Where Nanobubble Ozone Excels

Nanobubble technology shows particular promise in:

 

Pinnacle’s engineered contactors and injection systems can be adapted to support nano- and micro-bubble hybrid designs where needed.

Limitations and Considerations

While promising, nanobubble ozone systems are not universally superior. Consider:

• Energy input for nanobubble generation can be high (especially if using cavitation or specialized diffusers)
• Flow rate and backpressure limitations may restrict scalability
• Bubble size distribution can be difficult to control in varying water chemistry
• Requires careful monitoring of ozone residual and oxidation potential

Pinnacle evaluates these variables as part of site-specific system modeling to determine when nanobubbles add true value.

Nanobubble Ozone Is Real Science — But Still Needs Real Engineering

Nanobubble ozone technology offers real physics-based advantages, especially related to surface charge, oxidation proximity, and mass transfer efficiency. But the benefits are application-specific, and system integration remains key.

At Pinnacle Ozone Solutions, we combine deep ozone engineering with emerging fluid dynamics technologies to create systems that work under real-world constraints, not just in lab conditions. Whether you’re treating municipal drinking water, cooling tower blowdown, or high-organic surface water, we can help determine whether nanobubbles are worth the investment and design for success if they are.

Technical References

• Ohgaki, K. et al. (2010). Electrochemical Behavior of Nanobubbles in Water. Journal of Colloid and Interface Science
• Takahashi, M. et al. (2011). The Use of Microbubbles and Nanobubbles in Water Treatment. Industrial & Engineering Chemistry Research
• Tsuge, H. (2014). Micro- and Nanobubbles: Fundamentals and Applications
• Pinnacle Ozone Solutions: Internal CFD modeling and system performance data (2021–2024)