Experimental study of carbon dioxide absorption by Fe₂O₃@glutamine/NMP nanofluid

In this study, for the first time, the nanoparticle (NP) of Fe₂O₃@glutamine (C₅H₁₀N₂O₃) was synthesized to improve the Fe₂O₃ properties in absorbing carbon dioxide (CO₂) using the base fluid of hydrous N-methyl-2-pyrrolidone (NMP) solution (50 wt%), as a physically powerful CO₂ absorbent. To do this, several nano-NMP solutions, in different weight percentages of NPs, were first prepared. Then, in a batch setup, the nano-NMP solutions were directly exposed to CO₂ gaseous (at the pressures of 20, 30, and 40 bar) to clarify the effects of the mass percentage of NPs and initial pressure on CO₂ absorption. Results clearly illustrated that Fe₂O₃ nanofluid was not stable more than 0.025 wt%. However, Fe₂O₃@glutamine nanofluid was stable approximately two times more than Fe₂O₃ nanofluid due to the presence of glutamine as a hydrophilic agent in the structure of Fe₂O₃@glutamine. Moreover, in comparison to the base fluid (NMP solution), although Fe₂O₃ increased CO₂ absorption up to 9.14%, Fe₂O₃@glutamine NPs caused the CO₂ absorption to increase up to 19.41%, which can be determined as the chemical reactions of two amino groups in the glutamine structure with CO₂ and also higher stability of Fe₂O₃@glutamine NPs compared to bare Fe₂O₃ NPs. To achieve accurate results, all the mentioned experiments were repeated 5 times. The performance of Fe₂O₃ and Fe₂O₃@glutamine NPs after the fifth trial reduced by less than 3.5%, which reveals that the synthesized NPs had almost stable efficiency throughout their applications.