Toward Sustainable Scaled-Up Synthesis of Lignin-Derived Carbon Nanoparticles Using a Furnace Aerosol Reactor: Insights from a Life Cycle Assessment

A key aspect of circular economies is using sustainable pathways for processing advanced materials. While significant advances have been made in the discovery of novel materials that have innovative functionalities, rarely is attention provided to a holistic analysis to ensure that processes are sustainable. Rigorous analysis methodologies must be used to compare alternative processing methods. In this study, a comprehensive life cycle assessment (LCA) is conducted to evaluate a continuous and single-step aerosol synthesis approach in comparison to conventional batch pyrolysis methods for producing high-surface-area (porous) carbon materials. First, porous carbon nanoparticles (CNPs) are synthesized using a lab-scale aerosol reactor, and LCA is conducted to identify the key processing parameters contributing to their environmental impact. These results are then successfully used to guide the design of an optimized scaled-up aerosol reactor, achieving up to 75% reduction in global warming potential compared to conventional scaled-up batch pyrolysis techniques. Finally, the role of particle size and pyrolysis energy source in the environmental impact of CNP synthesis is systematically investigated. Overall, the simple (single-step, continuous, and rapid) operation and promising sustainability of the aerosol technique highlight its significant potential for the scalable synthesis of carbon nanomaterials from lignin.