(592d) Synthesizing DAC Hydrophobic Polymers with Various Form Factors

An increase in the emission of atmospheric CO₂ has caused global concerns. According to a report published by the Intergovernmental Panel on Climate Change (IPCC), it is expected that CO₂ emissions will rise from the current 36 Gt/yr to between 48 and 55 Gt/yr by the year 2050 as energy demand increases between 40% and 150%. Additionally, based on the Paris Climate Agreement in 2015, a limit of 2 °C was set for the global temperature increase while targeting an even lower limit of 1.5 °C. Since emission reduction alone cannot be a solution to climate change, negative emission technologies have gained much attention. Direct Air Capture (DAC) is one of the promising negative emission technologies that can capture CO₂ directly from ambient air and reduce the CO₂ concentration in the atmosphere. Thus, to achieve that, sorbents with high capturing capacity, low cost and fast kinetics are required. The current study investigates a series of amine-based DAC polymers with hydrophobic characteristics utilized in the humidity-driven CO₂ capture setup. We synthesized series of [2(Methacryloyloxy)ethyl]trimethylammonium chloride (TMAEMA-Cl) , Di(ethylene glycol) dimethacrylate (DEGDMA) and 2,2,2-Trifluoroethyl methacrylate (TFMA) membranes with various ion exchange capacities. These sorbents with quaternary ammonium cations on their backbone and bicarbonate counterions absorb CO₂ when exposed to ambient air and release it when in contact with an aqueous solution. The capturing process is driven by the energy generated from the evaporation of water. To further investigate the capturing capacity of the hydrophobic sorbents, they were ground into powder. The powdered sorbents were then added to the surface of an adhesive and tested in moisture-swing set up for different cycle times. The capturing capacity and kinetics of the two form factors were then investigated for various ion exchange capacities. Herein, we studied designing and synthesizing flexible and porous sorbents with high stability and fast kinetics to be used in the moisture-swing CO₂ capture mechanism and the effect of form factor on the kinetics of the sorbents.