Zinc Ferrite/Amine-Functionalized reduced graphene oxide nanocomposites for High-Efficiency CO2 separation

Developing advanced adsorbents with high adsorption capacity and selectivity for CO2 separation from flue gas, a significant contributor to global warming is a critical area of research. Using a hydrothermal method, this study synthesized a series of zinc ferrite/amine-functionalized reduced graphene oxide (ZF/rGO-MEA) nanocomposites with varying rGO-MEA to ZF ratios. This research marks the first systematic exploration of these nanocomposites as potential CO2 adsorbents. The composites were characterized using XRD, FTIR, BET, and FESEM-EDX techniques. CO2 adsorption measurements were conducted at 25 degrees C and 65 degrees C and pressures ranging from 1 to 9 bar. To optimize the CO2 adsorption capacity, we employed response surface methodology (RSM). Under optimized conditions, the nanocomposites achieved a notable CO2 adsorption capacity of 15.512 mmol/g at 25 degrees C and 9 bar. The CO2 adsorption isotherms were well-described by both the Langmuir and Freundlich models, with R2 values exceeding 0.99 for both and lower absolute average relative error (AARE) values, suggesting that the Freundlich model provided a slightly better fit and reflected the potential for multilayer adsorption on heterogeneous surfaces. The adsorption kinetics aligned with the fractional order model, showing R2 values above 0.94. The ZF/rGO-MEA30 composite demonstrated a CO2 adsorption capacity of 3.92 mmol/g at room temperature. Additionally, ZF/rGO-MEA30 exhibited impressive CO2/N2 IAST selectivity and easy regeneration, maintaining 90.56 % of its capacity after multiple adsorption-desorption cycles, making it a promising candidate for CO2 capture from dry flue gas.