Public Research Seminar by Sustainable Energy and Environment Thrust, Function Hub, HKUST(GZ) - Valorization of Sustainable and Waste Feedstock for Energy and Environmental Sustainability

In this talk, I will describe our research progress in valorizing waste feedstock to chemicals and fuels based on energy-efficient and green methods. First, I will talk about non-thermal plasma-based novel conversions of biomass. Despite extensive studies, conventional thermochemical methods can only produce 10-58% levoglucosan. We found that by combining non-thermal plasma pretreatment and subsequent pyrolysis, we can produce nearly 80% levoglucosan. We discovered that the plasma treatment introduced a novel radical-based depolymerization mechanism, which is much more selective than the concerted mechanism of cellulose depolymerization. In another study of plasma electrolysis, we combined the solvent and plasma effects to selectively convert whole biomass under atmospheric pressure.  Levoglucosenone and furfural with respective yields of up to 44.9% and 98.0%, were produced from red oak in the single-step process in addition to obtaining a selectively oxidized lignin. Non-thermal plasma was also used to co-convert waste plastics and CO2 under atmospheric pressure to produce oleochemicals and syngas. We found that during their co-conversion, CO2 served as a powerful cracking agent and oxidant to deconstruct polyolefins, while the plastics acted as a carbon sink to synergistically enhance CO2 conversion. By controlling the reaction, we obtained up to 98% fatty alcohols from polyolefins without catalysts. Finally, I will describe our integrated process for upcycling halogen-containing co-mingled municipal solid. By utilizing polar aprotic solvents as the conversion medium, we leveraged the hazardous wastes as an asset to promote the acid-catalyzed depolymerization of cellulosic wastes into high-value chemicals and recovered the dechlorinated reactive hydrocarbons as a clean solid fuel or oil absorbent.