Synthesis of NaX zeolite-graphite amine fiber composite membrane: Role of graphite amine in membrane formation for H2/CO2 separation

Pore surface modification of zeolite membrane is a challenging area to combat the trade-off between the high flux and high selectivity of the gas separation membrane. Herein we report facile method of pore along with defects modification of NaX zeolite membrane by incorporating graphite amine (Ga) into the membrane structure. Permeation properties of different membranes were evaluated by single gas permeance of H₂, CO₂ and separation factors for mixed gas H₂-CO₂ with different mixture ratio. These studies were done at room temperature and 100–300 kPa feed pressure. The results show that Ga is not only active for defect removal of NaX membrane but also enhanced the formation of NaX zeolite from mother sol. In addition, presence of graphite amine into NaX zeolite membrane increase the permeance of H₂ from 5.1 × 10⁻⁷ mol m⁻² s⁻¹ kPa⁻¹ to 36.5 × 10⁻⁷ mol^l m⁻² s⁻¹ kPa⁻¹ with increase of feed pressure 100–300 kPa feed pressure due to its hydrophobic properties and separation factor of H₂-CO₂ enhanced up to 31 for H₂-CO₂ mixture gas compared to literature reported value 6.5 for FAU membrane over 3-aminopropyltriethoxysilane functionalized alumina. Herein for the first time we report that graphite amine catalyzes for the formation of NaX zeolite in addition to pore modification in zeolite membrane.