Researchers from the University of Texas at Austin and Penn State have solved a complex problem of producing clean water at lower costs.
We all know that desalination membranes remove salt and chemicals from water. This process is crucial in cleaning the water and thus providing proper health to society. Even though the idea of pushing salty water and getting the clean water from the other side seems simple, it contains complex intricacies we are yet to understand.
The research team in partnership with DuPont Water Solutions solved an important part of this mystery, thus giving us an option to reduce the costs of clean water production. The problem was desalination membranes are inconsistent in density and mass distribution which lower their performance. To increase the amount of clean water these membranes create, the solution is to uniform the density at the nanoscale.
The paper published recently in Science journal mentions a 30-40% increase in efficiency in the membranes tested which means they can clean more water while using significantly less energy leading to increased access to clean water and lower water bills. And this was possible by creating membranes with uniform density at the nanoscale.
Manish Kumar, an associate professor in the Department of Civil, Architectural and Environmental Engineering at UT Austin, who co-led the research, said that reverse osmosis membranes are used for cleaning water but we still don’t know about them. All the improvements and developments in these were done in the dark over the past 40 years, thus limiting our knowledge on how water moves through them.
The working of reverse osmosis membranes includes applying pressure to salty feed solution on one side. Minerals stay there while water passes through. Researchers said that this process still depends on a large amount of energy and they are focusing on improving the efficiency of the membranes.
“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. It is important to have clean water available in low-resource areas as shortages, droughts are more prone to occur with increasingly severe weather patterns.
It all started when DuPont researchers found that thicker membranes were actually proving to be more permeable. This was a surprise, as conventional knowledge was that thickness reduces how much water could flow through the membranes.
Using state-of-the-art electron microscopes at the Materials Characterization Lab of Penn State, the team which also includes researchers from Iowa State University, developed 3D reconstructions of the nanoscale membrane structure. They modelled the path water takes through these membranes to predict how efficiently water could be cleaned based on structure. Greg Foss of the Texas Advanced Computing Center helped visualize these simulations, and most of the calculations were performed on Stampede2, TACC’s supercomputer.
Tyler E. Culp et al. Nanoscale control of internal inhomogeneity enhances water transport in desalination membranes. Science, Jan 1st, 2021 DOI: 10.1126/science.abb8518
Press Release: University of Texas at Austin