Effects of different amin-based core-shell magnetic NPs on CO2 capture using NMP solution at high pressures

Abstract

In this work, different modified magnetic nanoparticles (NPs) including Fe3O4–NH2, Fe3O4-proline, Fe3O4-lysine, Fe3O4@SiO2–NH2, Fe3O4@SiO2-proline, and Fe3O4@SiO2-lysine were synthesized to enhance the properties of Fe3O4 NPs in carbon dioxide (CO2) absorption via functionalizing various chemical agents on the surfaces of Fe3O4 NPs. For the investigation of CO2 absorption improvement, the NPs at different weight percents were dispersed in aqueous N-Methyl-2-pyrrolidone (NMP) solution (50 wt%) as a very strong physical absorbent of CO2; and the nano/NMP solutions were in direct contact with CO2 at a high-pressure batch setup. The impressions of different NPs, the initial pressure of CO2 and mass nanoparticle concentration on CO2 absorption were elucidated. The experimental results revealed that Fe3O4, Fe3O4–NH2 and Fe3O4-proline nanofluids were not stable at high concentrations. So, they increased the CO2 absorption rate just up to 7.64%, 15.14% and 15.88% as compared to the base fluid. However, Fe3O4-lysine, Fe3O4@SiO2–NH2, Fe3O4@SiO2-proline and Fe3O4@SiO2-lysine nanofluids by applying chemical agents as a sort of stabilizer and chemical reactant of CO2, improved the equilibrium CO2 absorption up to 19.41%, 23%, 25.53% and 28.49%, respectively.