A team of researchers has developed a new kind of “smart” dynamic membrane that could make desalination more viable in parts of the world that depend on it, particularly in the Middle East and North Africa. The enhanced membrane reduces fouling, a common problem that makes desalination—already an expensive proposition—more costly, say the researchers.
The research represents a step forward in the development of a new generation of dynamic membranes capable of self-cleaning “in an energy-saving and environmentally benign manner, which will effectively improve the cost-effectiveness of the overall process of potable water production,” says Panče Naumov, a professor at New York University-Abu Dhabi and the lead researcher.
The team, which is applying for a patent, is seeking partners to scale up the technology.
The NYU team, working in collaboration with the Institute for Membrane Technology in Italy, demonstrated that embedding heat-sensitive crystals into polymers added to porous membranes traditionally used for desalination significantly extended the life of the membranes by enabling them to self-clean and remove scaling. Over time, the reduced fouling of membranes also will reduce membrane replacement frequency, the researchers say.
The addition of the thermosalient crystals (TS) activated the membranes’ capacity to move in response to heat. “When we heat [the membrane] just a bit or just wash it with warm water around 40°C, the crystals actually convert an otherwise static membrane to be more dynamic,” explains Ejaz Ahmed, a university research scientist.
The motion from the crystals enables the membrane to descale and avoid fouling. The TS crystals are very small, between 200 micrometers and 500 micrometers, “but they gave a huge impact on the overall performance of the membranes,” he adds.
In tests performed, the research team found that adding TS crystals increased membrane water capacity by 50%. Moreover, membranes were tested through five cycles with no decline in their performance.
“There’s an urgent need for energy-efficient membranes capable of water desalination and other separation technologies that eliminate fouling issues without utilizing harsh chemicals as cleaners,” says Naumov.
The findings were published in the peer-reviewed journal Nature Communications earlier this fall.
