Implementable and Sustainable Upcycling of Medical Plastic Waste to Liquid Highly Branched Alkanes via Tandem Catalytic Cracking-Hydrogenation Strategy
Guanyu Zhang, Yuan Jiang, Qing Cheng, Xin Zhang, Ge Kong, Tianqi Cao, Chun Shan, Jin Wang, Fangqi Liu, Roger Ruan, Hanwu Lei, Xuesong Zhang, Lujia HanAbstract
Recalcitrant plastic waste (RPW) poses a significant environmental and health challenge due to its persistent nature and potential contamination with toxic chemicals and biohazards. Upcycling RPW containing mixed polyolefins, contaminants, and additives often struggles to achieve stable operation, controlled molecular breakdown, and selective production. Here, we report a robust tandem catalytic cracking−hydrogenation (TCCH) strategy for upcycling the real-world RPW into highly branched alkanes. The TCCH upcycling of RPW (medical syringe) delivered an exceptional transportation-fuel yield (66.82 C-mol %), dominated by iso-alkanes (80.61 C-mol %) with a multibranched iso-alkane proportion reaching 86.15%. Experimental mechanism investigation and in situ DRIFTS characterization indicated that hydrogenation of unsaturated species occurred exclusively during the low-temperature catalytic process (200 °C), with no evidence of hydrocracking, ensuring the preservation of liquid medium-chain iso-alkanes. Furthermore, the potential profitability of the TCCH strategy makes it economically viable, and it also exhibits a positive impact on global warming potential (−2.79 kg CO2 eq). This work introduces a straightforward, readily scalable, and sustainable TCCH strategy in enabling a circular economy for RPW via chemical upcycling.