(631b) Efficient Waste-to-Value Conversion: Synthesizing Carbon Microspheres from Brewers’ Spent Grain Via HTC

This study presents a sustainable and innovative approach to managing brewers’ spent grain (BSG)—the brewing industry’s most abundant byproduct—through hydrothermal carbonization (HTC). Traditionally repurposed as animal feed or disposed of, BSG poses significant waste management challenges. Our work demonstrates that HTC not only converts BSG into energy-rich hydrochar but also generates process water laden with valuable organic compounds such as furans, HMF, phenols, and organic acids. By leveraging these compounds, we have developed a method to synthesize carbon microspheres with promising applications in energy storage, water purification, catalysis, and carbon dioxide capture.

Experimental investigations reveal that reaction conditions—specifically elevated temperatures (180–240°C) and lower pH levels—facilitate rapid and uniform microsphere formation, as confirmed by dynamic light scattering and scanning electron microscopy analyses. Conversely, lower temperatures yield a broader size distribution of microspheres, underscoring the critical influence of process parameters on product quality.

In collaboration with industry partner SoMax Circular Solutions, ongoing efforts are focused on optimizing the synthesis rate, functional properties, and purity of the microspheres. This research not only advances our understanding of HTC process water utilization but also contributes to the circular bioeconomy by transforming a challenging waste product into high-value materials. The outcomes of this study hold significant implications for sustainable waste management and the development of renewable energy solutions within chemical engineering.