Scientists Say They Have Solved Desalination Mystery, Improving Efficiency

Photo courtesy of Tyler Henderson/Penn State

Scientists believe they have solved one of the biggest mysteries about desalination — exactly how reverse osmosis membranes work to remove salt and other chemicals from water — a breakthrough they say could help make the process more efficient and cheaper.

“Reverse osmosis membranes are widely used for cleaning water, but there’s still a lot we don’t know about them,” Manish Kumar, a chemical engineer at the University of Texas, Austin and co-author of the new research, said in a statement. “We couldn’t really say how water moves through them, so all the improvements over the past 40 years have essentially been done in the dark.”

A team of researchers from the University of Texas and Pennsylvania State University, in partnership with DuPont Water Solutions, discovered that desalination membranes are inconsistent in mass distribution and density. These inconsistencies can impair the performance of reverse osmosis, they found. By making the membranes more uniform in density at the nanoscale, the researchers were able to increase desalination efficiency 30 to 40 percent, therefore cleaning more water with less energy and lowering the cost. The findings were published earlier this month in the journal Science.

The discovery comes at a critical time, when climate change, population growth, and pollution are threatening access to safe drinking water. “Freshwater management is becoming a crucial challenge throughout the world,” said Enrique Gomez, a professor of chemical engineering at Penn State who co-led the research. “Shortages, droughts — with increasing severe weather patterns, it is expected this problem will become even more significant. It’s critically important to have clean water availability, especially in low-resource areas.”

—Genevieve Tarino