(371h) Epoxide-Modified Amine-Based CO2 Adsorbent for Direct Air Capture

A large portion of CO2 in ~5.2 gigatons (Gt) is released in relatively small quantities from distributed sources emitted each year in the U.S. Therefore, for such emissions, point source CO2 capture is not feasible and direct air capture is an indispensable part of a diversified portfolio of technologies to mitigate U.S. greenhouse gas emissions. Successful direct air capture (DAC) technologies are required to separate high purity CO₂ (e.g., >95%) with high selectivity toward CO₂, low regeneration energy requirements, minimum chemical and thermal degradation, reliability, long lifetime, etc.

In this study, epoxide-modified amino polymer-based sorbent has been studied for DAC potential. The sorbent performances were examined using epoxide-modified amino polymer-loaded silica substrates. The sorbent showed the high adsorption capacities of ~1.8-2 mmol CO₂/g of sorbent from 400 ppm CO₂ in ambient air between 25-40 °C with fast adsorption kinetics. It showed robust performances with minimum oxidative and thermal degradations over >1,000 adsorption and desorption cycles. The sorbent could also be regenerated at <100 °C that can potentially reduce the CO₂ desorption thermal energy requirement with <100 kJ/gmol CO₂.