An illustration from Aurora Clark's Science at Breakfast lecture on the microscopic view of global challenges in chemical separations.
Our environment is filled with mixtures, whether it is the air we breathe, the water we drink, or the earth we walk on. Often, separating mixtures is key to human health - for example, creating clean water supplies or recycling materials. Understanding how mixtures are separated, and optimizing this process, is a challenging task - and this is exactly what University of Utah Chemistry Professor Aurora Clark is doing.
Clark was the featured presenter November 7th at the College of Science’s Science at Breakfast event staged at the Natural History Museum of Utah.
“A major issue is that separating materials currently consumes a massive amount of energy,“ Clark explains, citing distillation as an easy example. “As such, chemists try to develop low-energy separation methods to create an environment where such isolation will happen spontaneously.” Achieving spontaneity means that chemists have to leverage the laws of thermodynamics, which include the energy stored in matter (called enthalpy) and entropy (which represents how energy is distributed in matter). Likening the reaction to a rock atop a hill, spontaneity means that that rock will begin rolling without the need of an extra push.
Such a breakthrough would have monumental effects on the recycling of rare materials. For example, the palladium in mobile phone capacitors is sourced to just a handful of areas, with Russia producing roughly 40% of the world's supply. As geopolitical tensions rise, the incentive to recycle this palladium grows in turn, but such isolation is tricky. It is difficult to develop a separation system that selectively grabs palladium in the complex mixture found in cell phones while ignoring other metals. The question of how to remedy this, by using changes in entropy, is the focus of Clark’s research, which uses the power of the U’s supercomputer to simulate the separations process. Computational geometry and data science play a key role in this pursuit.
By studying the patterns of interactions in complex mixtures, Clark seeks to control the amount of entropy change, which in turn makes it favorable for molecules and metals to selectively move across a separating barrier. Although in its early stages, the idea of using entropy to improve the efficiency of separating mixtures is moving at a rapid pace because of the technological advances of supercomputers and data science. If mastered, the recycling of critical materials like palladium would be significantly simplified, massively reducing energy consumption and optimizing our own self-sufficiency.
Aurora Clark is a relatively new addition to the U’s faculty, having joined in 2022. She completed a PhD at Indiana University, postdoctoral work at the Los Alamos National Laboratory, and spent almost two decades as a professor of Washington State University’s Department of Chemistry.
By Michael Jacobsen
Science @ Breakfast is a lecture series that features U faculty sharing their latest, cutting-edge research — while enjoying a meal. If you would like to be invited to our next Science @ Breakfast, please consider a donation to the College of Science at https://science.utah.edu/giving.