Credit: Erik Zumalt, Cockrell School of Engineering, The University of Texas at Austin

A multidisciplinary group of engineers and scientists has discovered a new method for water filtration that could have implications for a variety of technologies, such as desalination plants, breathable and protective fabrics, and carbon capture in gas separations. The research team, led by Manish Kumar in the Cockrell School of Engineering at The University of Texas at Austin, published their findings in the latest issue of  Nature Nanotechnology .

The study, which brought together researchers from UT Austin, Penn State University, the University of Tennessee, Fudan University and the University of Illinois at Urbana-Champaign, was initially inspired by the way our cells transport water throughout the body and began as an attempt to develop artificial channels for transporting water across membranes. The aim was to mimic aquaporins, essential membrane proteins that serve as water channels and are found in certain cells. Aquaporins are fast and efficient water filtration systems. They form pores in the membranes of cells in various parts of the body – eyes, kidneys and lungs – where water is in greatest demand.

Kumar and the team didn’t manage to mirror the aquaporin system exactly as planned. Instead, they discovered an even more effective water filtration process. Unlike the body’s individual aquaporin cells, which function effectively independent of one another, the membranes developed by Kumar’s research group didn’t work well alone.

But, when he combined several of them to create networks of “water wires,” they were highly effective at water transport and filtration. Water wires are densely connected chains of water molecules that move exceptionally fast, like a train and its individual cars.

“We were trying to copy the already complicated water transport process used by aquaporins and stumbled upon an entirely new, and even better, method,” said Kumar, an associate professor in the Cockrell School’s Department of Civil, Architectural and Environmental Engineering. “It was completely serendipitous. We had no idea it would happen.”

These networks of artificial membranes could prove useful for separating salt from water, a filtration process that is currently inefficient and costly. The new membrane has shown impressive desalination properties, exhibiting far more selective salt and presumably other contaminant removal when compared with existing processes.

Abstract

Artificial water channels are synthetic molecules that aim to mimic the structural and functional features of biological water channels (aquaporins). Here we report on a cluster-forming organic nanoarchitecture, peptide-appended hybrid[4]arene (PAH[4]), as a new class of artificial water channels. Fluorescence experiments and simulations demonstrated that PAH[4]s can form, through lateral diffusion, clusters in lipid membranes that provide synergistic membrane-spanning paths for a rapid and selective water permeation through water-wire networks. Quantitative transport studies revealed that PAH[4]s can transport >109 water molecules per second per molecule, which is comparable to aquaporin water channels. The performance of these channels exceeds the upper bound limit of current desalination membranes by a factor of ~104, as illustrated by the water/NaCl permeability–selectivity trade-off curve. PAH[4]’s unique properties of a high water/solute permselectivity via cooperative water-wire formation could usher in an alternative design paradigm for permeable membrane materials in separations, energy production and barrier applications.

FULL PAPER ON  NATURE 

Original story from the University of Texas at Austin

Media

Taxonomy

• Filtration Solutions
• Filtration