Sci-fi origami rose could be a revolutionary water purifier

30 May 2019

A bouquet of black roses like this could produce litres of clean, purified water in a couple of hours. Image: Cockrell School of Engineering/University of Texas at Austin

Scientists have built a rose bulb from scratch to create a water purifier that far exceeds most modern designs.

When it comes to the beauty of a particular new rose, there’s much more than meets the eye. A research team from the University of Texas at Austin has demonstrated how the familiar floral pattern of the rose bulb is also excellent at collecting and purifying water.

In a paper published to Advanced Materials, the team revealed how the flower is a dramatic improvement on current methods. Each of the small flower structures cost just 2c to make, but can produce approximately two litres of water per hour per square metre.

The design is a new approach to solar steaming for water production, whereby energy harnessed from sunlight separates salt and other impurities in water through evaporation. The new rose shape is made from layered black paper sheets shaped into petals.

The bulb is then attached to a stem-like tube that collects untreated water from any source, making it easier for it to collect and retain more liquid. By comparison, current solar-steaming tech is typically expensive, bulky and produces limited results.

The black rose device with collecting jar underneath on a steel, corrugated stable.

The rose water purifier and collecting jar. Image: Cockrell School of Engineering/University of Texas at Austin

Drip from a rose

Speaking of its design, the team said that its decision to go with a rose shape was 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,” said Donglei Fan, who led the research.

Polypyrrole is a material known for its photothermal properties, meaning it’s particularly good at converting solar light into thermal heat. After experimenting with a number of different ways to shape the paper for optimum water retention, the researchers started to place single, round layers flat on the ground in direct sunlight.

While they showed promise, it wasn’t until Fan was inspired by The Black Tulip by Alexandre Dumas that the rose shape came to be.

Weigu Li, lead author of the study, said the device removes any contamination from heavy metals and bacteria, as well as removing salt from seawater.

“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. “This could inspire new paradigms of solar-steaming technologies in clean water production for individuals and homes.”

Colm Gorey was a senior journalist with Silicon Republic