Plasma-Surface Interactions I

Direct Air Capture (DAC) technologies offer promising perspectives for the decarbonation of industry. However, they still rely on thermal, energy expensive processes to regenerate the CO₂ adsorbent. Using non-thermal plasmas instead offers both a lower energy regeneration method and a recycling solution for the captured CO₂. To develop such an alternative process, a deeper understanding of the interaction between adsorbent surfaces and plasmas is crucial, yet hardly any in situ study of the mechanisms at play was conducted so far. In our work, pelletized samples of CaO and CaCO₃ as first well known test materials are studied using in situ, time resolved IR absorption spectroscopy in transmission, following the same procedure as described in [1]. This enables us to track the evolution of carbonates and surface alterations during sequences alternating adsorption (gas flow exposure) and regeneration steps (plasma exposure). Regeneration of carbonated samples in a fluidized bed configuration is also studied with OES and ex situ IR absorption spectroscopy, using the same adsorption-regeneration sequences. Combining surface and gas phase diagnostic in a single plasma-adsorbent system give precious insights on the processes at play, paving the way for the development of efficient DAC techniques using plasma-assisted adsorbent regeneration.

[1] : Garcia-Soto, Carolina A., et al. "CO2/CH4 glow discharge plasma. Part II: Study of plasma catalysis interaction mechanisms on CeO2." Plasma Chemistry and Plasma Processing 44.3 (2024): 1287-1326.