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Nanoscale control of internal inhomogeneity enhances water transport in desalination membranes

2020; American Association for the Advancement of Science; Volume: 371; Issue: 6524 Linguagem: Inglês

10.1126/science.abb8518

1095-9203

Tyler E. Culp, Biswajit Khara, Kaitlyn P. Brickey, Michael Geitner, Tawanda J. Zimudzi, Jeffrey D. Wilbur, Steven Jons, Abhishek Roy, Mou Paul, Baskar Ganapathysubramanian, Andrew L. Zydney, Manish Kumar, Enrique D. Gomez,

Membrane-based Ion Separation Techniques

Biological membranes can achieve remarkably high permeabilities, while maintaining ideal selectivities, by relying on well-defined internal nanoscale structures in the form of membrane proteins. Here, we apply such design strategies to desalination membranes. A series of polyamide desalination membranes—which were synthesized in an industrial-scale manufacturing line and varied in processing conditions but retained similar chemical compositions—show increasing water permeability and active layer thickness with constant sodium chloride selectivity. Transmission electron microscopy measurements enabled us to determine nanoscale three-dimensional polyamide density maps and predict water permeability with zero adjustable parameters. Density fluctuations are detrimental to water transport, which makes systematic control over nanoscale polyamide inhomogeneity a key route to maximizing water permeability without sacrificing salt selectivity in desalination membranes.