Researchers come up with water purifier costing less than 2 cents

In a new advancement, a team of researchers at The University of Texas, Austin, have come up with a new inexpensive water purifier which is inspired by the design of a 'Rose'.

Each flower-like structure will cost less than 2 cents and is capable of producing more than half a gallon of water per hour per square meter.

The study was published in the journal 'Advanced Materials'.

A team led by associate professor Donglei (Emma) Fan engineered a new approach to solar steaming for water production - a technique that uses energy from sunlight to separate salt and other impurities from water through evaporation.

The authors also tell about how an origami rose served as the inspiration behind the technology 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.

The purifier can be described as a portable low-pressure controlled solar-steaming-collection "unisystem." But its resemblance to a flower is no coincidence.

"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," Fan said.

Polypyrrole is a material known for its photothermal properties, meaning it's particularly good at converting solar light into thermal heat.

Before finding success, Fan and her team experimented with a number of different ways to shape the paper to achieve optimal water retention levels.

They began by placing single, round layers of the coated paper flat on the ground under direct sunlight. The single sheets showed promise as water collectors but not in sufficient amounts.

After toying with a few other shapes, Fan was inspired by a book she read in high school. Although not about roses per se, "The Black Tulip" by Alexandre Dumas gave her the idea to try using a flower-like shape, and she discovered the rose 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 vapor to dissipate from the material.

The device collects water through its stem-like tube - feeding it to the flower-shaped structure on top. 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.

"We designed the purification-collection unisystem to include a connection point for a low-pressure pump to help condense the water more effectively," said Weigu Li, lead author on the paper.

"Once it is condensed, the glass jar is designed to be compact, sturdy and secure for storing clean water."

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.

"Our rational design and low-cost fabrication of 3D origami photothermal materials represents a first-of-its-kind portable low-pressure solar-steaming-collection system," Li said.