Magnetic field‐assisted concentration swing adsorption for CO ₂ capture over <scp> Fe ₃ O ₄ </scp> /fibrous nanosilica‐PEI adsorbent

Abstract Magnetic field‐assisted concentration swing adsorption (CSA) provides an electrification‐compatible alternative to conventional temperature swing adsorption (TSA) by enabling rapid heating/cooling and energy‐efficient regeneration under near‐isothermal conditions, thereby eliminating the need for sensible heat input. Here, Fe 3 O 4 nanoparticles were integrated with fibrous nanosilica (FNS) and polyethylenimine (PEI) to construct a magnetically responsive adsorbent for near‐isothermal CSA of CO 2 . Benefiting from the radially fibrous pore structure of FNS, Fe 3 O 4 /FNS‐PEI70 exhibited fast adsorption kinetics (&lt;2 min) and a high CO 2 adsorption capacity (4.2 mmol/g) at 80°C. Magnetic induction enabled efficient adsorbent regeneration and acheived 92.6% CO 2 desorption at the same temperature. Humidity significantly enhanced CO 2 capture (10.6 mmol/g at RH = 80%) without affecting the CSA process, whereas SO 2 caused irreversible deactivation and NO showed negligible adsorption. Under concentration swing conditions studied, a theoretical regeneration energy of 2.0 MJ/ kg CO2 was estimated for magnetic field‐assisted CSA process, which was significantly lower than that of TSA, highlighting its promise as an energy‐efficient and scalable pathway for electrified CO 2 capture.