Rose inspired novel device to collect, purify water

Scientists have taken inspiration from roses to develop a low-cost device for collecting and purifying water, that could provide a portable source of water for homes in remote locations.

The flower-like structure, developed at The University of Texas in the US, can produce more than half a gallon of water per hour.

The team developed a new approach to solar steaming for water production that uses energy from sunlight to separate salt and other impurities from water through evaporation.

In a study published in the journal Advanced Materials, they outline how an origami rose provided the inspiration for developing a new kind of solar-steaming system made from layered, black paper sheets shaped into petals.

Attached to a stem-like tube that collects untreated water from any water source, the 3D rose shape makes it easier for the structure to collect and retain more liquid. Current solar-steaming technologies are usually expensive, bulky and produce limited results. The team's method uses inexpensive materials that are portable and lightweight.

It also looks just like a black-petaled rose in a glass jar and costs less than two cents, researchers said.

"We were searching for more efficient ways to apply the solar-steaming technique for water production by using black filtered paper coated with a special type of polymer, known as polypyrrole," said Donglei Fan, an associate professor who led the study. Polypyrrole is a material known for its photothermal properties, meaning it is particularly good at converting solar light into thermal heat.

The team experimented with a number of different ways to shape the paper to see what was best for achieving optimal water retention levels.

They began by placing single, round layers of the coated paper flat on the ground under direct sunlight. Researchers discovered the rose shape to be ideal.

Its structure allowed more direct sunlight to hit the photothermic material -- with more internal reflections -- than other floral shapes and also provided enlarged surface area for water vapour to dissipate from the material.

The device collects water through its stem-like tube -- feeding it to the flower-shaped structure on top. It can also collect rain drops coming from above.

Water finds its way to the petals where the polypyrrole material coating the flower turns the water into steam. Impurities naturally separate from water when condensed in this way.

The device removes any contamination from heavy metals and bacteria, and it removes salt from seawater, producing clean water that meets drinking standard requirements set by the World Health Organization, the researchers said.