Charged carboxymethyl chitosan based CO2-philic adsorbents for enhanced CO2 capture and release via frequency using steel mesh electric polarization device at low temperature

Electric polarization (EP) facilitates charge separation within carbohydrate polymers under an electric field—a phenomenon that has not been thoroughly explored for CO₂ capture. To investigate this effect, carboxymethyl chitosan (CMCS)-based molecularly imprinted polymers (MIPs) were applied as a shell layer over polyacrylonitrile fibrous membranes (Pfm), creating a core–shell Pfm/MIP that formed amide-rich, CO₂-attractive binding sites. The Pfm/MIPs were positioned between two conductive mesh electrodes, where an alternating electric field was applied during CO₂ adsorption. Without EP, the CO₂ adsorption of Pfm/MIP was measured at 0.90 mmol/g. However, under an EP frequency of 300 kHz and 16 V, the dynamic adsorption increased markedly to 1.66 mmol/g. At elevated frequencies (e.g., 1200 kHz), the amine dipoles fail to synchronize with the rapid field oscillations, leading to dielectric loss and promoting CO₂ release from the imprinted sites. At a partial pressure of 0.15 bar CO₂, the selectivity for CO₂ over N₂ ranged from 65.5 to 67.4, while the purity of the recovered CO₂ stream was between 92.7% and 93.9%. The Pfm/MIP system demonstrated recyclability across 70 cycles of alternating EP frequencies between 300 and 1200 kHz. This approach highlights the role of charged adsorbents in modulating CO₂ adsorption and desorption behavior.