Coal to carbon quantum dots via Fenton’s reagent

Abstract

Industrial scale-up of top-down synthesized carbon quantum dots (CQDs) is currently bottlenecked by the environmental hazards of harsh acidic oxidizers and a total lack of predictive process and techno-economic frameworks. This work addressis this gap by presenting a novel and environmentally friendly process for converting Wyoming Powder River Basin coal into carbon quantum dots (CQDs) by leveraging naturally occurring iron to drive an in situ Fenton reaction. XPS and FTIR characterization confirmed the formation of highly functionalized CQDs, validating the molecular models used in our kinetic analysis. A two-step sequential mechanism was developed and validated using a global basin-hopping optimization algorithm. Operating at an optimized 8-hour/90 °C regime, the process maximizes CQD yield (43%) while ensuring high photoluminescent quality. Process modeling and techno-economic analysis were performed on a potential coal-to-CQD process at pilot, intermediate, and industrial-scale production rates to establish the first commercial viability benchmarks for this green technology. It was found that pilot and intermediate-scale facilities could be built with limited capital investment. CQDs produced in these plants could be sold at prices lower than CQDs currently available commercially. Capital and operating costs at the industrial scale are significantly higher than those at the intermediate scale, but the staged deployment scheme presented here minimizes investment risk while allowing CQDs to move from niche uses as laboratory reagents into bulk commodity applications. Ultimately, these findings establish a scalable blueprint for repurposing fossil fuel resources into sustainable, high-value carbon materials.