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Innovative System Transforms Animal Waste into Valuable Chemicals
A groundbreaking collaboration between chemical engineers and animal scientists has resulted in a new method for extracting valuable industrial chemicals from animal waste, marking a significant advancement in the pursuit of circular economy principles and environmental sustainability.
At the University of Illinois Urbana-Champaign, researchers have developed a nanofiltration system that effectively separates volatile fatty acids (VFAs)—organic molecules essential for fine chemical production—from cattle manure that has been fermented in bioreactors. This system stands out for its energy efficiency, utilizing selective ion-exchange membranes within an electrochemical separation framework and achieving an 80% increase in energy efficiency compared to earlier electrochemical techniques.
“It’s remarkable that we can derive industrial chemicals like VFAs from manure,” stated Xiao Su, a professor of chemical and biomolecular engineering. “Our research moves us closer to a circular system, where waste can be recycled into valuable resources, enhancing the efficiency and sustainability of chemical production globally.”
The project was spearheaded by Wangsuk Oh, a postdoctoral researcher in Su’s team, and the findings were published in the journal Advanced Functional Materials, with the article prominently featured on the front cover of the February 5, 2025 issue.
Volatile fatty acids, including acetate, butyrate, and propionate, serve as chemical precursors in a variety of applications such as cosmetics, food additives, pharmaceuticals, and plastics. Traditionally, producing these compounds relies on carbon-heavy processes that utilize petrochemical feedstocks. An alternative that has gained traction is microbial anaerobic digestion, where microorganisms decompose biowaste. However, the primary challenge to widespread adoption of this method is the inefficient extraction of VFAs from the intricate mixtures produced.
To address this, the Illinois researchers adopted redox-mediated electrodialysis, an electrochemical separation strategy extensively explored by Su’s team. This method employs an electrical field to capture charged chemical species, but uniquely utilizes “redox” molecules that can modify their electrical structures dynamically, leading to reduced energy demands. When paired with selective membranes, the process can distinguish between VFAs based on their chemical structures.
“Electrodialysis is a widely used separation technique, primarily in water desalination,” Su explained. “However, conventional ion-exchange membranes are not tailored to differentiate the valuable VFAs required for chemical production. Our team has engineered new membranes that possess specialized properties enabling them to identify and separate various chemical species, including differently sized VFAs.”
In their experiment, Su’s research team teamed up with animal sciences professor Roderick Ian Mackie to showcase this new approach. They fermented a cattle manure broth and employed the redox-mediated electrodialysis nanofiltration system to isolate the lower-weight VFAs from the longer-chain VFAs and additional substances present in the mixture.
“This innovative strategy transforms waste generated from large-scale animal production into valuable industrial chemicals, addressing significant environmental concerns,” noted Mackie.
The electrical-based separation method is considerably more efficient and produces substantially less chemical waste compared to traditional separation processes. Furthermore, Su believes that with its adaptable design, this technology can be integrated into industrial applications effectively.
“The upcoming phase of our research focuses on implementing this technology on a larger scale,” Su remarked. “This requires advanced materials design and development to enhance the selectivity of the membranes further. Achieving this could lower both the costs and energy requirements associated with the process.”
Nayeong Kim and Hyewon Kim also contributed to this research.
Support for this study was provided by the Energy & Biosciences Institute through the EBI-Shell program.
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