Matrix-Sacrificial Chemically Recoverable Amide-Linked Porous Organic Polymer Sorbent-Based Membrane for Synergistic Gas Capture and Particulate Matter Filtration

Simultaneously addressing rising carbon dioxide (CO 2 ) concentrations and aerosol particulate pollution remains a significant challenge for public health and the environment. Integrating CO 2 -adsorbing porous organic polymers (POPs) into a scalable membrane offers a promising pathway to multifunctional materials capable of simultaneous gas separation and aerosol filtration. Herein, amide-functionalized POPs with high porosity and active amide sites were prepared through a solvothermal-assisted ammonium carboxylate salt method. The optimized amide POP (Am-POP) exhibited high separation selectivity towards CO 2 /N 2 (32) and C 2 H 2 /CO 2 (3), consistent with Q st values of 39 kJ mol -1 (C 2 H 2 ) and 31 kJ mol -1 (CO 2 ), indicating stronger interaction with C 2 H 2 than CO 2 . After incorporation into a cellulose acetate (CA) matrix, the Am-POP/CA membrane achieved a PM 2.5 filtration efficiency of 99% at a low basis weight of 0.5 g m -2 with 30 Pa pressure drop. Increasing the basis weight to 2.5 g m -2 further improved the filtration efficiency to 99.99%. Also, the intrinsic chemical stability of Am-POP enabled matrix-sacrificial recovery of the active POP adsorbent from the used membrane via acid treatment. The Am-POP sorbent recovery efficiency was 98%, 96%, 93%, and 65% after the 1 st , 3 rd , 5 th , and 10 th recovery cycles, respectively. A detailed membrane performance evaluation was conducted primarily for the first five cycles, highlighting both the potential and remaining challenges of the matrix-sacrificial adsorbent-recovery filtration membrane. This work establishes a viable matrix-sacrificial sorbent recovery strategy for developing multifunctional POP-based membranes, enabling partial sorbent recovery and reprocessing of the active sorbent into reconstructed membranes for gas adsorption and PM 2.5 filtration.