Researchers have lots of imagination. After developing plastic as solid as steel, other scientists from in Australia, Korea and in the U.S. have created a plastic which could cut CO2 emissions and purify water. Their new material mimics pores found in plants and is exceptionally efficient. As said one of the lead researchers, "it can separate carbon dioxide from natural gas a few hundred times faster than current plastic membranes and its performance is four times better in terms of purity of the separated gas." Now it remains to be seen if commercial companies are interested, either for water desalination or for natural gas processing plants.
You can see above a picture showing how the pores in this new material allow some chemical elements to pass through them while rejecting other substances. (Credit: CSIRO) You can see other images related to this new material on this page at the CSIRO (Commonwealth Scientific and Industrial Research Organisation) website. The above image was extracted from this short video (Windows Media Player format, 1 minute and 20 seconds, 3.34 MB). Here is a link to another video (QuickTime format, 2 minutes and 20 seconds, 7.17 MB) in which the researchers from CSIRO talk about this new plastic.
And the picture above shows how this new polymer enhances separation processes. "This unique hourglass shape effectively separates molecules based on their shape. Separation is more efficient, requiring less energy." (Credit: CSIRO) Here is a link to a larger version.
This project was led at CSIRO by Dr Anita Hill of CSIRO Materials Science and Engineering. But CSIRO researchers were not alone to work on this project. They collaborated with Professor Dr Young Moo Lee of Hanyang University in Korea, and Professor Benny Freeman of the University of Texas.
Now, here are some details about how this new plastic works. "The secret to the new plastic lies in the hourglass shape of its pores, which help to separate molecules faster and using less energy than other pore shapes. In plant cell membranes, hourglass-shaped pores known as aquaporins selectively conduct water molecules in and out of cells while preventing the passage of other molecules such as salt. The research shows how the plastics can be systematically adjusted to block or pass different molecules depending on the specific application. For example, these membranes may provide a low energy method for the removal of salt from water, carbon dioxide from natural gas, or hydrogen from nitrogen."
And here is a quote from Dr Anita Hill about the material: "The new plastic is durable and can withstand high temperature, which is needed for many carbon capture applications. Heat-stable plastics usually have very low gas transport rates, but this plastic surprised us by its heightened ability to transport gases."
This research work has recently been published in Science under the name "Polymers with Cavities Tuned for Fast Selective Transport of Small Molecules and Ions" (Volume 318, Number 5848, Pages 254-258). Here is the beginning of the abstract. "Within a polymer film, free-volume elements such as pores and channels typically have a wide range of sizes and topologies. This broad range of free-volume element sizes compromises a polymer's ability to perform molecular separations. We demonstrated free-volume structures in dense vitreous polymers that enable outstanding molecular and ionic transport and separation performance that surpasses the limits of conventional polymers."
Sources: CSIRO news release, October 12, 2007; and various websites
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