Distributed direct air capture of carbon dioxide by synergistic water harvesting

Abstract

Adsorption-based direct air capture (DAC) of carbon dioxide, using chemisorbents like solid amines, has been widely recognized as a sustainable measure to contain atmospheric CO₂ concentrations. However, the productivity and economic viability of DAC have been compromised by the high energy consumption for regenerating the adsorbents. Here, we show that by synergistically harvesting water and carbon dioxide from the atmosphere, we can regenerate the unit using in situ vapor purge at low energy and capital cost. The desorption of CO₂ is substantially enhanced in the presence of concentrated water vapors at around 100 °C, concurrently producing 97.7% purity CO₂ and fresh water without the use of vacuum pumps and steam boilers. Moreover, we demonstrate that the DAC prototype can also be powered by sunlight, which recovers 98% of the adsorbed CO₂, with 20% less energy demand, enabling sustainable carbon capture from air in a real distributed manner.