How chemical engineers are tackling earth’s sustainability challenges

On Earth Day, our focus naturally shifts to environmental responsibility and the pursuit of a sustainable future. Environmental policy plays a critical role in this while individual and collective actions can also make a big difference in communities across the world. But one of the most important factors in addressing our planet’s complex challenges is chemical engineering. Often overlooked, chemical engineering is at the forefront of developing innovative solutions for a healthier world.

From the pressing issue of plastic waste to safeguarding water resources and transforming dairy waste into valuable products, chemical engineering is a driving force behind many of the advancements necessary for a truly sustainable future. Nearly all of our faculty are involved in sustainability research. Let’s look more into what our faculty are contributing to this vital endeavor.

Mellow the yellow: New techniques clarify recycled plastic, increasing their value

Our engineers have developed a new solvent-based technique for removing stubborn pigments from recycled multilayer plastic packaging. The advance makes recycled plastic more commercially appealing—increasing its market value and moving the industry closer to “closing the loop” for recycled plastic. This is just another critical step for researchers in the Huber Lab group who have made great strides in chemical recycling through a pioneering process called solvent-targeted recovery and precipitation (STRAP) since 2020. Several labs in the Department of Chemical and Biological Engineering at the University of Wisconsin-Madison are now collaborating on STRAP research through the Department of Energy-funded Center for Chemical Upcycling of Waste Plastics. 

Root is part of a project turning plants into plastics

A team of researchers with the Great Lakes Bioenergy Research Center led by Thatcher Root, a professor of chemical and biological engineering, and chemistry professor Shannon Stahl, have developed a new process that could help make plant-based plastics and alternatives to fossil fuels more economically viable. The researchers developed a method using oxygen to break down a tough form of plant fiber called lignin into chemicals that resemble the building blocks of many plastics and textiles currently made from petroleum. Now, the team is developing new methods to scale up those advances from the lab to the industrial scale.

Machine learning solves complex solvent selection challenge

Plant fibers contain valuable chemicals that can be used to make biofuels, plastics, medicines, and other products, but separating and purifying them is challenging, especially without using toxic solvents. Now University of Wisconsin–Madison scientists have used machine learning to streamline the process of finding the best solvents for the job, balancing selectivity, efficiency, and environmental impact. That means instead of testing thousands of mixtures, researchers can instead focus on dozens of the most promising candidates, said Shannon Stahl, a professor of chemistry who led the project with Reid Van Lehn, Hunt-Hougen Associate Professor of chemical and biological engineering. Van Lehn said the process, which combines computer modeling with lab experimentation, could speed innovation of bioproducts as well as pharmaceuticals.

Teaching future generations

Many people assume plastic recycling is an efficient, mature technology. Students learn more in our course, CBE 562: Technology for Plastic Recycling. The goal of the course is to give students and understanding of the challenges and opportunities in the recycling industry. They look at a wide array of potential chemical solutions for recovering and reusing plastic polymers in a more sustainable manner, priming the next generation of chemical engineers to take serious note of the recycling industry.

Whitney Loo is engineering the heart of next-gen batteries

Batteries include two electrical terminals—one called a cathode and a second called an anode—and an ion-rich electrolyte in between. The chemical reactions among these elements determine how stable, efficient and durable a battery is. That’s where Loo’s research comes in. An expert in developing new polymers—materials with long chains of molecules like plastics, rubber and proteins—she is designing materials called “single-ion conducting polymer-blend electrolytes.” These new materials combine one polymer that contains ions and one that can transport ions. In other words, better batteries. Loo’s slightly goopy new electrolyte could enable next generation lithium-metal batteries by creating a stable interface with lithium metal. That stability reduces the threat of battery fires or explosions. It also cuts down on a phenomenon called dendrite growth, which can lower battery performance or lead to failures.

“Super algae” could suck phosphorus out of manure and keep waterways healthy

A team of chemical and biological engineering researchers has developed a new strain of cyanobacteria, also known as blue-green algae, which takes up 8.5 times the phosphorus compared to its wild counterpart. These supercharged bacteria are at the heart of the team’s new manure-treatment system, which prevents phosphorus in livestock waste from dairy farms from polluting waterways. Ted Chavkin, who works in the lab of Brian Pfleger, a Karen and William Monfre Professor, Vilas Distinguished Achievement Professor, and R. Byron Bird Department Chair, is co-lead author of a paper describing the work in the journal ACS Sustainable Chemistry & Engineering.

Harnessing energy and nutrients from biomass

The nonprofit Schmidt Sciences and the Foundation for Food & Agriculture Research (FFAR) have selected a multi-institution group of researchers to establish the new Center for Mineral and Metal Oxide Removal from Biomass (CMORE) at the University of Wisconsin-Madison.

CMORE’s main goal is to find ways to remove minerals and metal oxides from biomass before they undergo catalytic conversion. “We are looking at many different removal technologies. We want to extract minerals from the biomass and return them to the soil,” says CMORE executive director George Huber, a professor of chemical and biological engineering at UW-Madison. “Then we can make mineral and metal oxide-free biomass pellets, which can be used to produce fuels and chemicals through different downstream catalytic technologies.”

Creating plant-based “living refineries”

Baldovin-DaPra Professor Victor Zavala and Assistant Professor Quentin Dudley are part of a team selected by the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E), for a $2.8 million grant as part of its Vision OPEN 2024 program. The project is titled “Building Plant Chemical Platforms for Efficient Aromatic Production Directly from CO2.” The goal of the research is to develop plant-based “living refineries” technology that utilize sunlight energy and convert atmospheric carbon dioxide directly into aromatic compounds, essential to modern society. The technology will be applicable to the vast chemical industry, where aromatics serve as essential building blocks for many of society’s most important industrial products, including plastics, fuels, resins, and semiconductor materials. 

For future sustainable chemical processing, electricity breaks bonds

Led by Marcel Schreier, an assistant professor of chemical and biological engineering at UW-Madison, and Christine Lucky (PhDChE ’24), a team of chemical engineers has taken an important stride toward a greener, more selective way to steer hydrocarbon transformation into other chemicals. Using a finely controlled electrocatalytic system, the team developed a method to break the carbon-carbon and carbon-hydrogen bonds in butane using electricity, with enough precision to steer the process toward desirable end products. The process is early in an effort to use electricity to replace traditional chemical processing, which uses massive amounts of heat and pressure to transform petroleum and other hydrocarbons into thousands of chemicals, fuels and plastics.

Atomic-scale understanding of a new electrocatalyst could lead to more affordable and efficient fuel cells

In an invited review article for the journal Nature Chemical Engineering, Professor Manos Mavrikakis discusses new modeling methods for understanding the dynamic evolution of active sites generated by reactants and intermediates on catalyst surfaces under realistic reaction conditions, including temperature and pressure. This type of modeling could then be used in the rational design of new classes of catalysts that could be implemented for accelerating a wide range of thermally catalyzed and electrocatalyzed reactions. This atomic-level insight of the process provides a new understanding of how these materials function, and could lead to better, much more affordable transition metal nitride-based electrocatalysts and fuel cells.

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