Seminar by Yvan Gladich (Qatar Environment and Energy Research Institute)

Chemistry for a Sustainable Planet: Carbon Capture at Aqueous Amine Scrubbing Solutions for Novel Aerosol and Direct Air Capture Technologies

Ivan Gladich
Qatar Environment & Energy Research Institute

Carbon capture and utilization represents one of the most promising CO₂-based technologies aiming to mitigate the impact of CO₂ greenhouse gas on climate change, while converting carbon dioxide into added-value products/chemicals. Amine-based materials are commonly used as capturing substrates. In particular, controlling CO₂ conversion at aqueous amine (scrubbing) solutions is a key element toward the development of cost-effective industrial solutions, including the design of near-future devices for direct air capture (DAC) or exploratory aerosol-capturing technologies operating at low (e.g., ambient) partial pressure.

After a brief review of the current activities of my group in atmospheric and sustainable chemistry, I will present results on the stability of CO₂-monoethanolamine zwitterion and its chemical conversion to carbamate at the vapour/liquid water interface by first-principles molecular dynamics coupled with a recently introduced enhanced sampling technique for determining the free energy chemical landscape. Contrary to the bulk water case, our results show that both the zwitterion and carbamate ions are poorly stable at the vapour/amine aqueous interface, further stating the differences between the homogeneous and heterogeneous CO₂ chemical conversion, and suggesting different design strategies (e.g., the change of the solvent polarity) for the stabilization of the reaction intermediates. Finally, from a methodological perspective we demonstrate that computational approach adopted here is particularly suitable for the investigation of chemistry at/in soft matter, where the entropic contribution to reactions may not be negligible.

This work states the potential of novel atomistic simulation approaches in enabling the design of capture systems working at ambient CO₂ partial pressure, that may overcome the limits of the current absorbents and the well-known energy-consuming problem of scrubbing solution regeneration.