Enhanced CO2 Absorption and Desorption by Monoethanolamine (MEA)-Based Nanoparticle Suspensions

In this study, three different nanoparticles—SiO2, TiO2, and Al2O3—were employed to enhance the CO2 gas absorption by monoethanolamine (MEA) solvent. It is observed that, with increased solids loading, the total mass-transfer enhancement has a tendency to be dominated by the bubble breaking effect. It is concluded that nanoparticles result in an increased CO2 absorption rate of >10%. On the other hand, nanoparticles exhibit much more attractive impact on CO2 desorption. Under the same desorption extent, solvent with 0.1 wt % TiO2 nanoparticles saved 42% desorption time, compared to that without nanoparticles. Under higher heat flux density, more input heat would be supplied to the heat of desorption, rather than the heat of water evaporation, which is due to the enhancement of desorption rate by nanoparticles. The issue of particle aggregation was also investigated by analyzing the size distribution of nanoparticle clusters and zeta potential of MEA solvents.