New Membrane Breakthrough Promises Cleaner, More Efficient Desalination

​Ultrahigh-charge-density Membrane (Image credit: Springer Nature)    

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​Researchers at the University of Michigan have developed a new class of charged membranes that could dramatically reduce the waste and energy demands of desalination, offering a more sustainable approach to freshwater production.
Desalination plants, essential for supplying drinking water in arid regions, generate vast amounts of brine waste (approximately 1.5 liters for every liter of clean water), posing serious environmental risks, particularly to marine life and groundwater. Traditional methods of managing this brine involve energy-intensive evaporation or environmentally harmful disposal into oceans or underground.
The new membranes, detailed in a study published in Nature Chemical Engineering, overcome long-standing salinity limitations in electrodialysis—a low-energy method that uses electricity to separate salt from water. By packing the membranes with an unprecedented density of charged molecules, the researchers achieved enhanced ion rejection and conductivity, making it feasible to concentrate salt brine to the point of crystallization. This paves the way for recovering both fresh water and valuable minerals like lithium, magnesium, and potassium from seawater. The innovation comes from linking the charged molecules with carbon-based connectors that prevent swelling, a problem that dilutes charge density in conventional membranes. This customization allows the membrane's performance to be tuned for different applications, balancing ion selectivity and conductivity.
“Our technology could help desalination plants be more sustainable by reducing waste while using less energy,” said lead researcher Dr. Jovan Kamcev, assistant professor of chemical engineering. Postdoctoral fellow David Kitto added, “Water is such an important resource—it would be amazing to help make desalination a sustainable solution to our global water crisis.”
The work was funded by the U.S. Department of Energy and supported by the NSF through facilities at the University of Pennsylvania.
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