Development of novel nanoabsorbents by amine functionalization of Fe₃O₄with intermediate ascorbic acid coating for CO₂capture enhancement

Novel nanoabsorbents are developed CO2 capture enhancement by functionalized magnetite nanoparticles in a water-based nanofluid system. The functionalization of magnetic nanoparticles was performed using different organic and inorganic reagents: (3-Aminopropyl) triethoxysilane (APTES), tetraethyl orthosilicate (TEOS), and L(+)-ascorbic acid (AA). The first coating used AA followed by a secondary shell of SiO2, and then amine functionalization via APTES, creating the amine-functionalized double-coated magnetite (Fe3O4 @AA@SiO2-NH2). The CO2 adsorption capacity of the synthesized material was enhanced by 11% at ambient pressure, compared with that of amine functionalization without AA (Fe3O4 @SiO2-NH2). To evaluate the absorption enhancement of Fe3O4 @AA@SiO2-NH2 at 25 °C, concentrations ranging from 0.1 to 0.4 wt% were compared with those of the base fluid (water). The highest enhancement of 59.2% was obtained at a concentration of 0.3 wt%. A cyclic performance evaluation showed that the initial absorption capacity was reduced by only 7%. Owing to its nanoabsorbent stability, significant CO2 absorption enhancement, and high recyclability, Fe3O4 @AA@SiO2-NH2 will be a milestone in physical liquid absorption systems for a carbon free environment.