Researchers from the United States have found that changing the nanoscale structure of membranes leads to more thorough water purification. This will enable engineers to create more reliable filters.
Researchers from the University of Texas at Austin, Iowa State University, the Dow Chemical Company have presented a new method of water purification, they described it in the journal Science. It is based on understanding how membranes filter impurities from water.
“Although we have been using filters for many years, there is a lot we don’t know about how membranes work to filter water,” said Enrique Gomez, professor of chemical engineering and materials science and engineering at the University of Pennsylvania who led the study. “”We found that how you control the density distribution of the membrane itself at the nanoscale is really important to the efficiency of water production.”
The team used multimodal electron microscopy, which combines atomic detailed imaging with chemistry revealing techniques. This is how they determined which minerals for desalination are inconsistent in density and mass. The researchers mapped variations in the density of the polymer film in three dimensions with a spatial resolution of about one nanometer, less than half the diameter of a DNA strand. According to Gomes, this technological advance has played a key role in understanding the role of density in membranes.
Scientists used to think that the thicker the membrane, the less water is produced. However, it turned out that there is practically no correlation between these things. Filmtec, now part of DuPont Water Solutions, which makes numerous products for water desalination, has partnered with the researchers and funded the project so they will soon be producing thick membranes that are also permeable.