Project Status and Findings:
Information about this project is provided on the web pages below and by the project scientists on the Computing for Clean Water website. If you have comments or questions about this project, please visit the Computing for Clean Water forum.
The mission of Computing for Clean Water is to provide deeper insight on the molecular scale into the origins of the efficient flow of water through a novel class of filter materials. This insight will in turn guide future development of low-cost and more efficient water filters.
Lack of access to clean water is one of the major humanitarian challenges for many regions in the developing world. It is estimated that 1.2 billion people lack access to safe drinking water, and 2.6 billion have little or no sanitation. Millions of people die annually - estimates are 3,900 children a day - from the results of diseases transmitted through unsafe water, in particular diarrhea.
Technologies for filtering dirty water exist, but are generally quite expensive. Desalination of sea water, a potentially abundant source of drinking water, is similarly limited by filtering costs. Therefore, new approaches to efficient water filtering are a subject of intense research. Carbon nanotubes, stacked in arrays so that water must pass through the length of the tubes, represent a new approach to filtering water.
Normally, the extremely small pore size of nanotubes, typically only a few water molecules in diameter, would require very large pressures and hence expensive equipment in order to filter useful amounts of water. However, in 2005 experiments showed that such arrays of nanotubes allow water to flow at much higher rates than expected. This surprising result has spurred many scientists to invest considerable effort in studying the underlying processes that facilitate water flow in nanotubes.
This project uses large-scale molecular dynamics calculations - where the motions of individual water molecules through the nanotubes are simulated - in order to get a deeper understanding of the mechanism of water flow in the nanotubes. For example, there has been speculation about whether the water molecules in direct contact with the nanotube might behave more like ice. This in turn might reduce the friction felt by the rest of the water, hence increasing the rate of flow. Realistic computer simulations are one way to test such hypotheses.
Ultimately, the scientists hope to use the insights they glean from the simulations in order to optimize the underlying process that is enabling water to flow much more rapidly through nanotubes and other nanoporous materials. This optimization process will allow water to flow even more easily, while retaining sources of contamination. The simulations may also reveal under what conditions such filters can best assist in a desalination process.
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