Researchers at Tsinghua University use IBM's World Community Grid to study how water flows through carbon nanotube filters. Image credit: IBM
IBM used crowdsourced supercomputing power to discover that carbon nanotubes could filter water more efficiently and more cheaply than common water purification methods.
The researchers published their findings in the journal Nature Nanotechnology on Monday, July 6, showing how the tiny, hollow nanotubes – similar to the graphite in pencils – could filter out impurities in water. Previously, scientists thought that nanotubes would impede the flow of water too much to be effective filters.
However, natural, random thermal vibrations of the atoms in nanotubes actually reduce the friction between water and the tubes, enhancing the rate of water diffusion by more than 300 percent.
The experiment was led by the Center for Nano and Micro Mechanics at Tsinghua University in Beijing, China.
The crowdsourcing element came from the IBM World Community Grid, in which volunteer “civilian-scientists” use excess computing power on their home devices to boost IBM’s processing power by creating the equivalent of a virtual supercomputer.
Prior simulations were unable to replicate the water flow rates needed to realistically experiment with this method of filtration. However, the three million computers hooked up to the World Community Grid by more than 700,000 volunteers were enough to do the work relatively quickly, and without any cost to the scientists.
If the experiment had been performed commercially, it would have cost $15 million. Running on a single-processor PC, it would have taken over 37,000 years.
"Prior to our project, simulations of water flow in carbon nanotubes could only be carried out under unrealistically high flow-rate conditions," said Quanshui Zheng, Director of Tsinghua University's Center for Nano and Micro Mechanics, in a press release. "Thanks to IBM's crowdsourced World Community Grid, the Computing for Clean Water project could extend such simulations to probe flow rates of just a few centimeters per second, characteristic of the working conditions of real nanotube-based filters."
This new method of filtration could be used to improve fresh water purification, as well as to desalinate seawater. With freshwater dwindling around the world, more and more people may need to turn to a less costly purification process in order to use seawater for drinking and growing crops. The study could also contribute to the study of osmotic power, a process of creating energy from mixing freshwater and saltwater.
Looking even further into the future and other applications, a thorough understanding of nanotubes may help scientists understand how chemicals and drugs filter through the tiny openings in human cell walls. This could lead to improvements in the way medicine is distributed throughout the body.
Researchers from University College London, Tel Aviv University, University of Geneva, University of Sydney, Monash University, and Xi’an Jiaotong University also contributed to the research.