Comprehending the effect of functionalized silica nanoparticles on amine blends for efficient carbon capture from synthetic flue gas

Abstract

Amine-based absorbent was conventionally used for carbon capture, but its utility is limited owing to high-temperature operability, energy-intensive regeneration, lower recyclability, and corrosion issues. In this work, amine-derived nanoformulation is prepared using functionalized silica nanoparticles (fNPs), ethylene glycol, and conventional amines by a three-step preparation technique, followed by nanofluid stability and rheological studies. Rheological observations have shown viscosity decreases with temperature, and functionalized DEA (fDEA) has indicated viscous dominant behavior at 303 K and elastic dominant behavior at 323 K, and viscoelastic and viscous behavior for DEA at 303 and 323 K. Absorption experiments were conducted in an interfacial contact reactor using synthetic flue gas (CO₂: N₂–1:3 molar) at 303 and 323 K using water, water+functionalized nanoparticle, fDEA nanofluid, and conventional DEA (30 vol %) solution. fDEA demonstrates ∼8 % and ∼12 % higher molar absorption than DEA solution at 303 and 323 K. Moreover, fDEA has demonstrated ∼20 % and ∼25 % higher CO₂ capture efficiency (E30) than DEA solution at 303 and 323 K, respectively. Recyclability testing up to 3 cycles have shown better regeneration performance of fDEA than DEA. The superior absorption performance of fDEA for multiple cycles is attributed to additives and efficient micromixing during absorption and regeneration. This approach, in combination with other reactor contact strategies, will have an encouraging potential to capture CO₂ at industrial scales from high-temperature flue gas streams.