Interface-Engineered SiO ₂ @GO Nanohybrids for Enhanced CO ₂ Separation in Thin-Film Nanocomposite Membranes

Membrane-based gas separation has emerged as an energy-efficient and environmentally sustainable approach to mitigating anthropogenic CO 2 emissions. This study focused on the synthesis of a graphene oxide (GO)-grafted APTES-functionalized SiO 2 (f-SiO 2 @GO) nanocomposite and its incorporation into thin-film nanocomposite (TFN) membranes for CO 2 gas separation. The synthesized f-SiO 2 @GO were incorporated into the polyamide selective layer using an interfacial polymerization method. Physiochemical characterization confirmed the successful functionalization of the nanocomposite and its effective integration into the TFN membrane. Gas separation performance was evaluated using CO 2 and N 2 as feed gases at 25 ± 2 °C and 1 bar. The optimized TFN-2 membranes exhibited the highest CO 2 permeance of 3284.5 GPU and CO 2 /N 2 selectivity of 24.5 among the fabricated membranes. The enhanced separation efficiency is attributed to the synergistic interplay between functionalized silica and GO nanosheet. These findings suggest that these functionalized nanocomposites can serve as effective fillers to improve the performance of TFN membranes for CO 2 separation.