CO2 adsorption on polyethyleneimine -modified mesocellular siliceous foam: Influence of glycerol-based additives

Abstract

This study investigates the effects of glycerol and glycerol carbonate as adjuvants on the CO₂ adsorption of polyethyleneimine (PEI)-functionalized mesocellular siliceous foam (MCF), with a focus on post-combustion carbon capture applications. Material characterisation demonstrated the successful incorporation of PEI-adjuvant blends into MCF, with notable pore filling identified via nitrogen sorption analysis and indications of chemical interactions revealed through infrared spectroscopy. The evaluation of CO₂ adsorption for the materials was conducted under both dry and humid conditions at temperatures ranging from 75 to 115 °C. The branched PEI-glycerol composites showed a 49 % enhancement in CO₂ uptake at 75 °C in humid CO₂, indicating a synergistic interaction between glycerol and water. Adjuvants modestly enhanced the adsorption and desorption kinetics at low CO₂ concentrations and temperatures, especially within branched PEI systems. Yet the inclusion of adjuvants typically reduced CO₂ uptake and amine efficiency. Cycling experiments demonstrated a decline in performance and a gradual loss of mass, particularly at 115 °C, presumably resulting from the migration of PEI to the particle surface followed by thermal decomposition. Adjuvants provide kinetic advantages; however, their effects on stability necessitate additional optimisation to achieve a balance between performance and durability in practical applications.