For many engineers and scientists, nature is the world’s greatest muse. They seek to better understand natural processes that have evolved over millions of years, mimic them in ways that can benefit society and sometimes even improve on them.
An international, interdisciplinary team of researchers that includes engineers from The University of Austin has found a way to replicate a natural process that moves water between cells, with a goal of improving how we filter out salt and other elements and molecules to create clean water while consuming less energy.
In a new paper published today (May 20, 2021) in Nature Nanotechnology, researchers created a molecule-sized water transport channel that can carry water between cells while excluding protons and undesired molecules. These channels mimic the water transport functions of proteins in our bodies known as aquaporins. In our cells, uncontrolled transport of protons alongside water can be harmful because they can change the pH of cells, potentially disrupting or killing them.
This is the first instance of an artificial nanometer-sized channel that can truly emulate the key water transport features of these biological water channels. And it could improve the ability of membranes to efficiently filter out unwanted molecules and elements, while speeding up water transport, making it cheaper to create a clean supply.
“It copies nature, but it does so by breaking the rules nature has established,” said Manish Kumar, an assistant professor in the Cockrell School of Engineering’s Department of Civil, Architectural and Environmental Engineering. “These channels facilitate speedy transport of molecules you want, like water, and block those you don’t want, like salt.”
The research team’s artificial water channels can perform the same functions as aquaporins, which are crucial at a larger level for desalination, water purification and other processes for separating molecules. And they do so while transporting water 2.5 times faster compared to aquaporins.
The artificial channels are three nanometers in width by three nanometers in length. If densely packed into the correct size membrane, the channels can pass roughly 80 kilograms of water per second per square meter of membrane, while rejecting salts and protons at rates much higher than current commercial desalination membranes are capable of.
“These artificial channels in essence solve the critical technical challenges of only allowing water molecules to pass while excluding other solutes like salt and protons,” said professor Huaqiang Zeng of Department of Chemistry at Hainan University and the Institute…