One-Pot Self-Assembly Shaping of Polyamine-Supported Silica Adsorbents Using a CO2–Curable Silicate Binder

Abstract

Polyamine-containing porous adsorbents are promising materials for CO2 capture, but practical deployment requires shaping into mechanically robust bodies without sacrificing adsorption performance. Conventional shaping methods typically rely on high-temperature calcination with inorganic binders, which is incompatible with supported organic polyamines and necessitates separate shaping and amine impregnation steps. In addition, post-impregnation of highly viscous polyamine solutions often results in nonuniform amine distributions within shaped adsorbents. Here, we report a calcination-free one-pot self-assembly shaping strategy for polyamine-supported silica adsorbents using a CO2-curable sodium silicate binder. A homogeneous slurry containing fumed silica, polyamine, and sodium silicate was directly shaped and cured under CO2 at room temperature, enabling simultaneous shaping and amine incorporation in a single process. CO2 curing converted sodium silicate into a rigid silica network, providing mechanical strength without high-temperature calcination. Compared with conventional multistep routes, the one-pot strategy generated a more uniform distribution of amine species throughout the adsorbent body, leading to enhanced CO2 adsorption kinetics while maintaining CO2 uptake capacities comparable to those of the parent powder adsorbents. This strategy provides a simple and scalable route for manufacturing shaped amine adsorbents with minimal loss of performance upon shaping.