(699e) Enhancing the Separation Efficiency of Ultra-Selective 3D Canal Hydrocarbon Polymeric Membranes for Hydrogen-Based Separations after Long-Term Aging

Hydrogen (H₂) is gaining traction as a key player in global decarbonization efforts due to its efficiency as an energy carrier. Membrane-based separations are increasingly recognized for their energy efficiency and adaptability, making them promising for hydrogen purification. Despite advancements, challenges such as polymer physical aging persist, leading to decreased gas permeability over time. However, the unique aging behavior of 3D CANAL polymers, synthesized through efficient catalytic arene-norbornene annulation (CANAL) polymerization, holds promise for enhancing separation efficiency post-aging. Previous research on CANAL-Me-S6F showcased remarkable aging characteristics, achieving a 1000% increase in H₂/CH₄ permselectivity and only a 33% reduction in H₂ permeability after 158 days, surpassing the 2015 upper bounds. Building upon this foundation, our current investigation delves into the gas transport performance of ultra-aged (>365 days) 3D-CANAL polymers for H₂-based separations. We observed a substantial 6100% boost in H₂/CH₄ selectivity and a 2400% increase in H₂/N₂ selectivity with a mere 55% loss in H₂ permeability. Furthermore, we assess the stability of these ultra-aged polymers under industrially relevant conditions, including binary and ternary gas mixtures and high-temperature scenarios. Longer aging times notably enhance H₂/CO₂ selectivity due to increased size-selectivity, surpassing the 2008 upper bound. Additionally, simulations predict the membrane to possess high H2 permeability of 15000 barrer without losing H₂/CO₂ selectivity when temperature increases from 35°C to 190°C, a common process temperature post-water-gas-shift reaction. This allows the aged CANAL membranes to rival some of the best-performing membranes for H₂/CO₂ separations in the literature. In conclusion, this study elucidates the robustness and potential applications of ultra-selective hydrocarbon polymers for hydrogen separations, contributing to advancements in clean energy technologies and the broader landscape of sustainable energy solutions.