On the first International Day of Women and Girls in Science, we’re excited to highlight two ChemE professors — both appointed in recent years — that are creating innovative solutions in sustainability and the environment. This article originally appeared in the 2015 issue of Skulematters.
Making the most of rare earths
Rare earth elements (REEs) — neodymium, cerium, samarium and 14 others — are found in an increasing number of technologically advanced products. Their unique magnetic properties are critical for making everything from smartphones and earbud headphones to wind turbines and electric cars. Their ability to speed up chemical reactions makes them useful in manufacturing as well as in automotive catalytic converters. Because of their importance to the economy, developed countries including Canada have accelerated efforts to satisfy demand of rare earth elements.
Gisele Azimi (ChemE, MSE) is using her unique knowledge of materials science and chemical engineering to change the way we extract, utilize and recycle these elements. She is developing chemical processing techniques that can extract REEs not only from natural resources, but also from materials that would otherwise be discarded as waste. For example, Azimi and her team are creating processes that can be used on old automobile catalytic converters to recover not only REEs, but also precious metals such as platinum.
During her post-doctoral studies at MIT, Azimi discovered a new property of REEs: when made into ceramics, they have a powerful ability to repel water. These ceramics can be applied to airplane wings or wind turbine blades to prevent ice buildup, making these technologies safer. They can also be applied to steam turbine blades or condensers — key pieces of industrial process equipment — to increase efficiency and reduce energy use.
On the extraction side, Azimi and her team are currently optimizing a technique for recovering REEs from phosphogypsum, a byproduct of the fertilizer industry, as well as automotive catalytic converters. They also partnered with researchers at the U of T Engineering’s Centre for Advanced Coating Technologies to develop the spray-coating techniques needed to commercially apply their new water-repelling ceramics.
“Rare earth elements can address a wide range of sustainability issues, from better electric cars and wind turbines to more energy-efficient processes. I believe researching extraction and utilization of these elements paves the way to take on the big challenges in energy and the environment.”
Green Infrastructures to Remove Environmental Contaminants
Each year, humans use thousands of tonnes of organic chemical compounds, such as pharmaceuticals, antibiotics, pesticides and more. These substances eventually make their way into streams, lakes and oceans. Many of these compounds are known or suspected to have potentially toxic effects on these aquatic ecosystems and need to be removed. Yet, surprisingly little is known about how they move through the environment, or their final fate.
Elodie Passeport (CivE, ChemE) is dealing with this problem through two complementary strategies. Using isotope ratio mass spectrometry — a chemical analysis technique — Passeport and her team can trace the fate of the chemical contaminants in samples collected from industrial, agricultural and urban areas. For example, they can determine whether the chemicals are being broken down by bacteria or sunlight, or merely sticking to soil or clay. In the lab, Passeport and her team validate this work by building working models of wetlands or other natural and engineered ecosystems.
Passeport aims to usher in a new era of “green infrastructures” by redesigning wastewater treatment systems to take advantage of natural processes, including bacterial action, that break down or filter out harmful compounds. Her work will also influence government policy by helping to identify where compounds end up and which ones need to be regulated most urgently.
Passeport is collaborating with Ontario companies that design bioretention cells, a water treatment system that leverages natural processes to remove organic chemical contaminants from stormwater runoff. Her work will determine the roles played by each element of the system, including soil composition, water levels and vegetation, and help optimize overall function.
“My goal is to see better, more integrated management of environmental problems. This means small treatment systems in homes combined with efficient, large-scale processes that mimic nature. I want to put all my efforts into preserving our environment.”