Delivered as an aerosol spray, ozone nanobubbles can more effectively disinfect indoor spaces. 

AquaB (AquaB Nanobubble Innovations Ltd), a University College Dublin (UCD) spin-out company, today announced that it has developed a novel method of generating ozone nanobubbles in water with commercial disinfectant applications.

Ozone (O₃) is an inorganic gas molecule which has been used for more than 100 years as a safe and effective disinfection agent in many industrial and consumer settings.

Disinfecting effectiveness

It is a powerful disinfectant as it oxidises directly and penetrates a pathogen’s cell wall, thereby destroying the pathogen. However, in water, the half-life of ozone is approximately 30 minutes, limiting its disinfecting effectiveness.

Nanobubbles, tiny gas bubbles on the nanometre (nm) scale, (a human hair is ca. 60,000-100,000 nm wide), are thermodynamically metastable for many months or even longer due to their enhanced gas-transfer properties.

Given these properties with AquaB’s new method of generating ozone nanobubbles, ozone lifetimes in the nanobubble-aqueous form are substantially increased over and above traditional ozone solvation in water by an order of magnitude. This overcomes the limitations of using conventionally solvated ozone as a disinfectant agent.

Ozone nanobubbles, which can be delivered as an aerosol droplet spray, have therefore the potential to be used as a more effective and efficient spraying method to ozonate, sterilise or disinfect, indoor spaces. These ozone nanobubbles can also be added to bulk liquid water and used to eliminate bacteria and viruses in wastewater.

Energy-efficient method

AquaB was established earlier this year to commercialise a new energy-efficient method to generate and release substantial volumes of metastable, nano-scale gas bubbles in water.

This method is based on research carried out by Professor Niall English and Dr Mohammad Reza Ghaani at UCD’s School of Chemical and Bioprocess Engineering, who are the co-founders of AquaB.

Prof English, CEO, AquaB, said: “In our novel method of generating ozone nanobubbles, following direct ozone-gas generation, we apply our patented, energy-efficient nanobubble-generation approach in water via electric-field exposure, resulting in a combination of ozone (O₃) and oxygen (O₂) nanobubbles in solution.

More effective than chlorine

“These ozone nanobubbles serve as ‘batteries’ – or reservoirs – to replenish continually solvated-ozone levels for hours, and their gradual diminution and depletion over these much longer timescales, compared to ozone in the gas phase or traditionally solvated state, affords this 'nano-bubbly' water very potent steriliser or disinfectant properties – even more effective than chlorine.

“Delivering the ozone nanobubbles as an aerosol spray indoors, the ozone nanobubble water droplets adhere, by gravity and direct-spray contact to surfaces, such as chairs and desks, more effectively, thus ozonating or disinfecting the spaces and killing bacteria and viruses, including potentially SARS-CoV-2, for more prolonged periods of time in between spraying campaigns.”

Dr Mohammad Reza Ghaani, CTO, AquaB said: “Our plan now is to specifically test the ozone nanobubble technology, as water droplets in an aerosol spray, as an effective disinfectant against SARS-CoV-2.

Liberate indoor spaces

"This will hopefully help to liberate indoor spaces, and potentially crowded outdoor spaces, during COVID-19 for gatherings, whether professional, social or sporting.

“The company is also in discussions with a large-industry partner to help accelerate the commercialisation of the technology, and we also intend to liaise with public bodies.”

AquaB is a client company of NovaUCD, the Centre for New Ventures and Entrepreneurs, and is working closely with UCD’s knowledge transfer team to accelerate the commercialisation of AquaB’s nanobubble technology.

Prof English concluded: “We would like to thank Enterprise Ireland for their ongoing support to date which includes technology development funding and support with market development activities.”