Desalination can now clean water at a lower cost


Producing clean water at a lower cost might be on the horizon following Researchers in the University of Texas in Austin and Penn State solved a intricate desalination issue that has baffled scientists for years, until now.

Desalination membranes remove salt and other compounds from water, a process crucial to the well-being of society by cleaning billions of gallons of water to agriculture, energy generation and drinking. The idea seems straightforward — push bottled water clean water through and it comes out the other side — but it includes complicated desalination intricacies that scientists are trying to comprehend.

The study group, in partnership with DuPont Water Solutions, solved an important facet of this puzzle, opening the doorway to reduce prices of fresh water generation. The researchers decided desalination membranes are somewhat inconsistent in mass and density distribution, which may hold their own performance. Uniform density at the nanoscale will be the trick to increasing how much clean water the membranes may produce.

“Reverse osmosis membranes are widely used for cleaning water, but there’s still a lot we don’t know about them,” said Manish Kumar, an associate professor in the Department of Civil, Architectural and Environmental Engineering at UT Austin, who co-led the research. “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.”

The findings have been published in Science.

The paper documents an increase in efficacy in the desalination membranes analyzed by 30%-40%, meaning that they are able to clean more water when using less energy. That could cause greater access to clean water and water bills for individual homes and industrial users alike.

Reverse osmosis membranes operate by applying pressure to the salty feed solution on a single side. The minerals remain there while the water moves through. Even more effective than non-membrane desalination procedures, it takes a great deal of energy, the investigators stated, and enhancing the overall efficiency of these membranes may reduce that weight.

“Fresh water 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.”

The National Science Foundation and DuPont, making numerous desalination products, financed the study. The seeds for desalination were planted when DuPont researchers discovered that thicker membranes were really proving to be permeable. This came as a surprise since the conventional understanding was that depth decreases how much water can flow through the membranes.

The group linked to Dow Water Solutions, which is now paet of DuPont, in 2015 in a “water summit” Kumar organized, and they have been excited to figure out this desalination puzzle. The study group, which also includes researchers from Iowa State University, developed 3D reconstructions of the nanoscale membrane arrangement utilizing state-of-the-art electron microscopes in the Materials Characterization Laboratory of Penn State. They mimicked the path water takes through those membranes to forecast how effectively water could be cleaned dependent on construction. Greg Foss of this Texas Advanced Computing Center helped envision those simulations, and the majority of the calculations have been conducted on Stampede2, TACC’s supercomputer.

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