IBM virtual supercomputer aids clean water project

Scientists in China have discovered a phenomenon in which the use of carbon nanotubes, under specific conditions, could potentially lead to more efficient water filtering with less expense and impact on the environment. The discovery was enabled through IBM's virtual supercomputer, World Community Grid (WCG).

The calculations would have taken 37,000 years to perform on a single-processor PC

Carbon nanotubes are tiny, hollow structures made of a material related to graphite in pencils. They are so small that they may filter out impurities from water flowing through them. The scientific community initially expected that the nanotubes' narrow diameters would slow the water's flow but early experiments hinted that water is not impeded in the expected way as it passes through nanotubes.

Researchers from Tsinghua University in Beijing now hope to optimise the nanotubes and apply them to improve water filtration and seawater desalination. As freshwater reserves dwindle worldwide, an improved and less costly purification process could help provide access to safe drinking water.

Using IBM's WCG meant more than 700,000 volunteers worldwide could channel the surplus processing power of their computing devices to scientists for use in conducting simulations. As a result, researchers were able to carry out an unprecedented, massive computational simulation study to find out what was behind this surprise.

Prior simulations performed by the scientific community were unable to study the process at realistic water flow rates because that would have required considerably more costly computing power than typically available.

The WCG simulation revealed that under certain conditions, the natural, random thermal vibrations of atoms in nanotubes could have a significant effect on water moving through them. The researchers discovered that these vibrations, called phonons, can enhance the rate of water diffusion by more than 300% as a result of reduced friction. Almost 100 million calculations were performed by the supercomputer for the Computing for Clean Water, and would have taken 37,000 years to perform on a single-processor PC.

Quanshui Zheng, director of Tsinghua University's Center for Nano and Micro Mechanics, said: “Prior to our project, simulations of water flow in carbon nanotubes could only be carried out under unrealistically high flow-rate conditions. Thanks to IBM's crowd-sourced 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.”