Preparation of Highly Aminated Polystyrene Resin Beads for CO2 Adsorption

Abstract

A methodology of using chloroacetylated polystyrene resin (PS-COCH₂-Cl) to initiate the ring-opening polymerization of oxazolines was established to prepare highly amininated polystyrene (PS) resin beads for CO₂ adsorption. The structure of the resulting material was fully characterized by FTIR, BET, TGA, and XPS, and the results suggested that the chloroacetyl group was more reactive in initiating the ring-opening polymerization of oxazolines than the known chloromethyl groups, which eliminated the use of iodide salts that are costly. The resulting material could adsorb CO₂ at an equilibrium adsorption capacity of 3.15 mmol/g at 25°C and 1 atm, and the adsorption isotherms conformed to the Freundlich isothermal model, indicating a multi-layer adsorption type. Kinetic study suggested that the adsorption was predominantly governed by chemical interactions with physical adsorption playing a supportive role. For a simulated flue gas of 15% CO₂/N₂, 50°C, relative humidity of 80%, SO₂ concentration of 50 ppm, the adsorption performance of PS-COCH₂-LPEI was even improved and the capacity can be well retained for at least 20 adsorption–desorption cycles, demonstrating a promising application prospect of this solid polyamine material in removing CO₂ from flue gas.