(298c) Direct Air Capture Via Magnetic-Induced Swing Adsorption on Amine-Modified Fe3O4@MIL-101 and Fe3O4/SBA-15 Composites

Abstract:Electrification of sorbent regeneration in direct air capture (DAC) systems offers a promising route to reduce energy consumption and improve process efficiency. This study develops a series of magnetic field-responsive sorbents (MF-RSs) for use in magnetic-induced swing adsorption (MISA) processes tailored for DAC applications. Two types of MF-RSs, Fe₃O₄@MOF and Fe₃O₄@aminosilica, were synthesized via in-situ growth and co-precipitation methods, exhibiting CO₂ adsorption capacities of 2.1 mmol/g and 1.5 mmol/g, respectively (35 °C, 500 ppm CO₂/N₂). Equilibrium and dynamic CO₂ adsorption/desorption experiments were conducted under both dry and humid environments to evaluate structure–performance relationships. Addtionally, MISA regeneration studies revealed key trade-offs between heat capacity and magnetization that affect thermal diffusion and molecular transport. Under N₂, O₂, and H₂O atmospheres, magnetic-field-induced CO₂ desorption behavior was examined to uncover transport mechanisms. The results highlight the importance of balancing CO₂ uptake with magnetic responsiveness in the design of smart sorbents. Both classes of MF-RSs exhibited stable regeneration behavior, reinforcing the potential of MISA as a low-energy, field-responsive regeneration strategy for next-generation DAC systems.