Matthew Cowan: Silver ions to the rescue!
Story by Margo White We’re often told that obliging industry to significantly reduce energy consumption and energy-related emissions would be bad for business and the economy. There may be some truth in that, but it also seems apparent that if there was the political and economic will, there would be the scientific ways. Consider, for instance, the research done by Matthew Cowan, who did his PhD at the University of Otago under Professor Sally Brooker, a MacDiarmid Institute Principal Investigator. Then, he looked at molecular switches for information storage. These days he’s a postdoctoral associate at the University of Colorado Boulder (CU-Boulder), where he divides his time between the Chemistry and Chemical Engineering departments, investigating separation technologies. And with considerable success. He has, for instance, developed a technology that could reduce the energy required to purify ethylene, the chemical used to make polyethylene, the world’s most popular plastic, used in shopping bags, shampoo bottles, bullet-proof vests and spaceships etc. In the United States alone, it now takes more than 46 million megawatt-hours of electricity a year to produce ethylene, about the same amount of energy produced by seven average-sized nuclear power plants. Part of the ethylene problem is that the process that produces it also makes ethane, which is almost identical in structure. Consequently, the purification process—currently an energy-intensive distillation technique—is both difficult and costly. Yet Matthew and colleagues at CU-Boulder have shown that a material made of molecules containing silver ions could greatly reduce the amount of energy needed to separate ethylene and ethane. “This silver ion can be thought of as working like a hand,” says Matthew, explaining that this hand can tell the difference between the two gases, and ‘grabs’ the ethylene out of the mixture. “It has a selectivity of ‘grabbing’ 390 ethylene molecules for every ethane molecule.” Or, put another way, the material has 13 times more separating power than any other solid materials used to separate the two gases. The results of his findings were published in the prestigious Angewandte Chemie International Edition, and recognised as a ‘Very Important Paper’ (VIP), which means that it was considered to be in the top five percent of articles published by the journal. He and his team are now talking to potential industrial partners to invest in developing the technology for an engineering process. Matthew is keen that his research does not end with the publication of a paper. “After I did my PhD in what was essentially blue sky research, I really wanted to do something that could actually have an impact on the world and address the issues that challenge us as a society.”