New nanotechnology speeds water from air harvesting

Words and images Marie Lowe

A start-up company in northern New South Wales is developing new technology to harvest water from the air faster than ever before.

Vesi Water in the regional city of Tamworth was born during the crippling drought of 2017-2020, when founder Llewellyn Owens was investigating water sources for the hydrogen industry.

Harvesting vapour from the air is not a new concept. Atmospheric water generators (AWGs) are already available in units that produce up to 20 litres of day for a home, or on a commercial scale of more than 10,000 litres a day.

Graphene oxide is being used in new technology to harvest water from the air more efficiently.

Most systems use a condenser and cooling coil technology to extract water from the air.

But a 2018 research report, “Extraordinary water absorption characteristics of graphene oxide”, sparked Owens’ interest.

“I was working very closely with the University of New South Wales on water sources for hydrogen development and I found there were very few solutions out there,” says Owens.

“I read this paper around the water absorption characteristics of graphene oxide that found the water uptake capacity was more than five times higher than anything already in use.

“The air is our biggest fresh water reservoir. At any time, the atmosphere contains more than 142 trillion tonnes of water. That’s six times more than all the freshwater rivers and lakes in the world.”

The research report found graphene oxide (GO) had a water uptake capacity of up to 0.58 gram of water per gram of graphene oxide. This is “significantly higher” than silica gel.

“More interestingly, the adsorption and desorption kinetics of GO is five times higher than silica gel,” the report noted.

Silica gel is the material used in the small packets used to keep your online shopping free of moisture – and is also used as a desiccant, or water-absorbing sponge, in atmospheric water generators.

Owens says he realised GO could have the potential to go beyond existing technology.

Generating hydrogen with water from air

He and a small team, in partnership with the University of New South Wales, set about building a prototype for new air to water technology.

“This was during COVID, and you couldn’t go into the uni,” Owens says. “We built a very basic model using lots of parts from Bunnings.”

Vesi Water graduate engineer Jerick Perez takes a drink from one of the new water units being launched by the company. The initial water units will not include the graphene oxide technology.

The technology worked, producing pure, drinkable water, and the manufacturing process and application have now been patented by Vesi Water.

“Our proof of concept is a game-changer, confirming extremely efficient air-to-water generation systems that can harvest 200 litres to 10,000 litres, and beyond, of clean water per day from air-borne humidity,” Owens says.

“Water is a huge global market, and our early estimates indicate that Vesi Water system is already cheaper than bore water, trucking, local rainwater harvesting, and is also on par with desalination despite its early stage development.”

Vesi Water has scaled up the early prototype and is in the process of creating a pilot plant in Tamworth in partnership with the University of New England and Japanese manufacturer Nisina Materials, which will assist in clean technology for graphene oxide production.

Vesi Water is looking to bring to market products scaling from small units to power drip irrigation, through to household units about the size of an air-conditioning unit and commercial production-sized units, all of which can be solar-powered.

The technology also allows water to be harvested in climates with as low as 20% humidity, where conventional units operate on 40% humidity or above.

Owens says Vesi Water’s vision is to make a “significant humanitarian impact” by helping to alleviate the global water crisis.

The technology is already attracting interest from the poultry industry and the tomato growing industry, where on-site production of water could help moderate humidity in glasshouses.

The Greenlight Project is a year-long look at how regional Australia is preparing for and adapting to climate change.

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