Carbon dioxide absorption in water/nanofluid by a symmetric amine-based nanodendritic adsorbent

Abstract Serious and immediate action is needed to reduce carbon emissions and prevent catastrophic global climate change. In this work, we investigate the enhancement of CO 2 absorption in water by preparing and adding different types of modified Fe 3 O 4 nanoparticles to a water-base fluid, creating a nanofluid system that has gained increasing interest over the last decade. The nanoabsorbents are prepared by using different inorganic and organic reagents; tetraethyl orthosilicate (TEOS), (3-Aminopropyl) triethoxysilane (APTES) and diethylenetriamine. These coat the as-synthesized, magnetite Fe 3 O 4 core-shell nanoparticles resulting in a symmetric, amine-based nanodendritic CO 2 adsorbent. These reagents were chosen due to their range of various functional groups and hydrophobic or hydrophilic nature, as well as to assess their effect on the absorption of CO 2 . In addition to evaluating the prepared nanofluidic system (nanoparticle/water nanofluids), we also studied the effects of nanoparticle loading, hydrophilicity, the quantity of nanoparticles, reaction temperature, and absorption time on the CO 2 absorption. The nanodendritic absorbent, with a high density of symmetric amine functional sites and hydrophilicity (Fe 3 O 4 @SiO 2 -SNH 2 ), showed the highest enhancement of CO 2 absorption (70%) in comparison to the water-based solution, which is higher than that of most reported nanofluidic systems. Fe 3 O 4 @SiO 2 -SNH 2 also retains its performance even after being regenerated for 5 absorption cycles, losing only 3% of its absorption efficiency over this period. Finally, the significant CO 2 absorption, high recyclability under low temperature, and mild regeneration in a water-based nanofluid, as a “green” solvent, make this nanofluidic system a unique candidate for atmospheric CO 2 capture.