Investigation of Carbon Dioxide Absorption Using Different Functionalized Fe₃O₄ Magnetic Nanoparticles

In this work, the absorption of carbon dioxide (CO₂) using functionalized Fe₃O₄ magnetic nanofluids was investigated. Nanoparticles of Fe₃O₄, Fe₃O₄–proline, Fe₃O₄–lysine, and Fe₃O₄@SiO₂–NH₂ were dispersed in water and methyldiethanolamine (MDEA) in order to improve the absorption performance using a high-pressure setup, in which CO₂ and absorbents were in direct contact in a closed system. The effects of initial pressure of CO₂, nanoparticle type, and nanoparticle concentration on absorption performance were examined. The obtained results indicated that the presence of functionalized Fe₃O₄ nanoparticles resulted in better results at pressure 30 bar in distilled water as a physical absorbent, and they enhanced the absorption up to 17.61 and 34.23% compared to nonfunctionalized Fe₃O₄ and distilled water, respectively. Subsequently, the dispersed nanoparticles in MDEA solution showed that the functionalized Fe₃O₄ nanoparticles were effective for CO₂ separation even in chemical absorbents, and under the best conditions, they enhanced the capacity of absorption up to 16.36% at pressure 40 bar. Moreover, zeta potential analysis revealed that Fe₃O₄–lysine and Fe₃O₄@SiO₂–NH₂ nanoparticles are more stable than nonfunctionalized Fe₃O₄ and Fe₃O₄–proline in the base fluid.