Design of Hyperbranched Amine Polymer-Functionalized\nPolyHIPEs for Rapid CO<sub>2</sub> Capture and Separation

A novel\nsolid amine adsorbent meso-PDVB@HBPE-<i>x</i> was prepared\nby impregnating and cross-linking the hyperbranched\namine polymer (HBP-NH<sub>2</sub>) in a mesoporous polydivinylbenzene\n(meso-PDVB) substrate with an open-cell structure. The optimum preparation\nconditions were investigated in detail, and the CO<sub>2</sub> adsorption\nperformance of prepared adsorbents was conducted by a fixed bed dynamic\nadsorption system. It is suggested that beneficial from the low viscosity,\nthe intramolecular cavity of HBP-NH<sub>2</sub>, and the open-cell\nstructure of meso-PDVB, the best adsorbent meso-PDVB@HBPE-8, which\nwas slightly cross-linked with ethylene glycol diglycidyl ether (EGDE),\nexhibited a high CO<sub>2</sub> adsorption capacity of 5.64 mmol/g\nunder 25 °C and wet conditions and quick adsorption kinetics\n(a high <i>Q</i><sub>b</sub>/<i>Q</i><sub>e</sub> ratio of 0.92). Compared with the low-molecular-weight amine tetraethylene\npentaamine, HBP-NH<sub>2</sub> processes a higher molecular weight\nand is easily modified. Through cross-linking with EGDE, the N content\nand CO<sub>2</sub> adsorption capacity of meso-PDVB@HBPE-8 remained\nstable during 20 absorption (at 25 °C)–desorption (at\n90 °C) cycles under wet conditions, showing great regeneration\nstability. The adsorbents showed great potential in CO<sub>2</sub>/CH<sub>4</sub> separation, achieving a CH<sub>4</sub> productivity\nof 18.86 mmol/g from a 15 mL of CO<sub>2</sub>/CH<sub>4</sub> (20:80,\nv:v) mixed gas. The strategy of synergistically designing the amine\nand substrate porous structures demonstrates its advantage in the\npractical application of CO<sub>2</sub> adsorption and separation.