University Of Delaware: Creating Value From Waste

Wilmington DE

21 January, 2022

6:29 PM

Description

Press release from the University of Delaware: January 19, 2022 UD researchers report low-pressure method to convert industrially processed biomass into plastics, chemicals It's no secret that we need more sustainable materials if we hope to help the planet. Bio-derived materials are one potential option, but they must be economical if anyone is going to use them. For instance, a better bio-based milk jug would be great. However, if the milk sells for $20 per gallon because the cost of the jug increases from $1 to $17, no one will buy it. "The ability to take something like technical lignin and not only break it down and turn it into a useful product, but to do it at a cost and an environmental impact that is lower than petroleum materials is something that no one has really been able to show before," said Epps, who leads the NSF GCR efforts at UD and is the Allan and Myra Ferguson Distinguished Professor of Chemical and Biomolecular Engineering. He also holds a joint appointment in the Department of Materials Science and Engineering. Everyday ingredient overcomes high-pressure hurdle One of the main problems with upgrading lignin is that most of the processes to do it operate at very high pressures and are expensive and hard to scale. Major drawbacks of current industrial techniques include the safety concerns, capital costs and energy consumption associated with traditional solvents, temperatures or pressures used in the process. To overcome these challenges, the research team replaced methanol, a traditional solvent used in lignin deconstruction, with glycerin so the process could be done at normal (ambient) atmospheric pressure. Glycerin is an inexpensive ingredient used in liquid cosmetics, soaps, shampoos and lotions for its moisturizing capabilities. But here, the glycerin helps break down the lignin into chemical building blocks that can be used to make a broad range of bio-based products, from 3D-printing resins to different types of plastics, flavor and fragrance compounds, antioxidants and more. Using glycerin provided the same chemical functionality as methanol, but at a much lower vapor pressure, which eliminates the need for a closed system. This change allowed the researchers to do the reaction and separation steps simultaneously, leading to a more cost-effective system. Operating at atmospheric pressure is safer. Just as important, it also provides a straightforward route to scale beyond small batches and run the process continuously, creating more material with less labor in a cheaper, faster process. Developing the process so it was repeatable and consistent took about a year and involved contributions from undergraduate students, including Paula Pranda, a co-lead author on the paper and a 2021 UD Honors graduate. Pranda, now a doctoral student at the University of Colorado, Boulder, helped optimize the process. She also researched available data sets on what types of products the team could create and estimated the physical properties of those materials. This allowed co-author Yuqing Luo, a chemical engineering doctoral student in Professor Marianthi Ierapetritou's group, to model the system to see if it was economically feasible. Luo's work showed that the UD team's low-pressure method can reduce the cost of producing a bio-based pressure-sensitive adhesive from softwood Kraft lignin by up to 60% in comparison to the higher-pressure process. The cost advantage was less pronounced for the other types of technical lignins used in the study, but softwood Kraft lignin is among the most abundant types of technical lignin generated by the pulp and paper industry. This press release was produced by the University of Delaware. The views expressed here are the author's own.