“Our society is built around stuff,” says chemical-engineering professor Susannah Scott, the first endowed chair in a group intended to total four in the Mellichamp Sustainable Materials and Product Design cluster. “The stuff comes from somewhere in the form of resources, which we transform into products that we use and eventually throw away. That whole process has an impact on the environment.”
The sustainability group was established in 2014 as the third Mellichamp research cluster. The program began in 2001, when longtime member of the UCSB and UC Academic Senates Professor Emeritus Duncan Mellichamp and his wife, Suzanne, funded a single chair in process control. Two full clusters followed, in systems biology (2003) and globalization (2008), codifying the format of each cluster having four chairs, its own area of emphasis, a life span of fifteen years, and a mission of solving problems while developing important new areas of expertise at UCSB.
The Sustainable Materials and Product Design cluster was established with the goal of developing materials and processes that could reduce the environmental impact of manufacturing. A broader, affiliated goal was to provide more people with technologies that enable a high standard of living without exceeding Earth’s capacity to supply the necessary raw materials and absorb the inevitable byproducts of such activities.
Joining Scott as chairs in the cluster are chemistry professor Mahdi Abu-Omar, who came to UCSB in 2016 with expertise in “green” chemistry, and chemical engineer Phillip Christopher, who arrived at UCSB in January 2018. Both are also experts in catalysis. A search is under way for the final chair, whose appointment will be at the Bren School of Environmental Science & Management and who will focus on resource systems analysis, which incorporates modeling to identify ways to reduce energy and resource consumption for industry.
Scott’s goal within the cluster is to improve the efficiency and reduce the environmental impacts of chemically intensive catalytic processes, which are involved in about ninety percent of manufacturing and, according to Christopher, are responsible for wasting a few percent of all the energy the world uses.
Scott also focuses on minimizing the formation of undesired products in catalysis, reducing demand for rare metals by creating catalysts based on materials that are abundant in the earth, and scaling up environmentally friendly methods of catalysis for depolymerizing the lignans in fibrous plants so that the attached sugars, in the form of cellulose, can be used as biofuel.
A key challenge facing the cluster researchers is the fact that, as Scott says, “We’ve built a society that has been basically dependent on carbon as the principal source of fuel and the vast majority of chemical components used to make fibers, polymers, paints, adhesives, and much more. Getting and using oil is a highly optimized process that has a hundred-year head start on bio-derived chemical fuels and products. It works very nicely.”
But, she adds, because of the negative environmental impacts of extracting and using fossil fuels, “In the future, we will have to let go of that idea.”
Abu-Omar focuses his research on turning waste products into energy. Like Scott, he works on lignin but comes at it from a different perspective. “Lignin can be used to produce interesting materials like those we make from petroleum today,” he explains. “In my group, we use chemistry to take the lignin polymer apart and form structures that we can then put back together in a way that gives them unique new properties like those of structural plastics.”
Abu-Omar’s group has made strides in enhancing the selectivity of that process, so that it yields only the products, or molecules, they want. “We’ve figured out how to get two or three products from lignin instead of a dozen products,” he says.
He is also taking a visionary look at reusing plastics beyond recycling them, such as, for instance, transforming a used plastic bottle into something other than another bottle.
"We want to think about it in a non-conventional way, so that the used bottle is now a feedstock,” he explains. “It is a human-made waste product that contains value in its energy and its content. Can we now use the concepts of green chemistry creatively to make from it starting molecules that can then be used to make other economically and environmentally viable materials?
“Working with lignin,” he adds, “We learned a lot about how to break carbon-oxy-
gen bonds that are inherent in those materials. If we’re going to take oil-based polymers apart in a meaningful way, we have to learn to manipulate carbon-carbon and carbon-hydrogen bonds. Right now, we’re at that initial stage of designing chemistry to be able to take the long carbon chains and make smaller carbon chains from them with some selectivity.”
Providing a glimpse into how the cluster functions, he says, “Once we understand the chemistry, we might say, ‘How can we make this environmentally sustainable?' So we might then go to Susannah, who can help us come up with catalysts that can perform the process faster and more efficiently. And someone like Phil can help us to think about what would be missing to make this lab work scale up. What are the challenges and how should we design the reaction? Maybe I was doing the chemistry under certain conditions that would cost too much to scale as to make it impractical. And going beyond the cluster, someone from political science might say that we should be thinking about how the molecules we’re making might be perceived and accepted — how political forces might affect the technology.”
Working in that collaborative way, he says, “really helps you to get outside your comfort zone and understand how other scholars view the problem and think about it. I might have a way of approaching the chemistry, and then someone shows me that, down the road, we might have to think about policy or water usage. And all of a sudden you say, ‘Oh wait, can I reformulate my thinking to address that?’ It’s very enriching and leads to better science.”
Phillip Christopher works in two main areas of catalysis. One is adapting to the shift from oil to natural gas as the primary resource for manufacturing commodities. Natural gas is much cleaner than oil in terms of sulfur and heavy-metal content, and it has a lower greenhouse-gas footprint, because the hydrogen content relative to carbon is higher than for oil.
Still, Christopher says, “It presents some challenges. Some products — for example, ethylene, propylene, and butene, the major reactants used to produce plastics — used to come from oil, but now we have to make them from natural gas. The difference is that the oil you pull from the ground has big long-chain hydrocarbons, and we can exploit well-understood, long-used processes to break them down into smaller molecules, which are then used to make things. But the natural gas you pull from the ground is made up of the tiniest hydrocarbons, so different chemical conversion processes are required to form critical reactants.”
Like Scott, Christopher is also working to develop catalytic processes that require fewer precious metals, especially platinum-group metals, and particularly the amount of such metals used in automobile catalytic converters. “We need catalytic converters to clean automobile exhaust more efficiently and in a way that requires fewer precious metals,” he says. A recent joint grant from the National Science Foundation and the Ford Motor Company further supports his research in that area.
Scott adds, “One of the valuable aspects about these Mellichamp chairs is that, to make an impact, you really do need to bring in people from different areas. I could also imagine a sociologist coming in and saying, ‘How do we get people to think more critically? How do we get people to stop thinking that because they’re only one person, their actions don’t matter?’ In that context, trying to bring together people with really different perspectives makes sense.”
“Sustainability is something that the whole UCSB campus has a big footprint in,” Scott notes. “People feel strongly about it, and we all have different perspectives. The College of Engineering perspective is that you need solutions that work on a large scale. Our part in that is chemical manufacturing.”