A Low-Cost Dual Layer Deca-Dodecasil 3 Rhombohedral-Alumina Hollow Fiber for CO₂/CH₄ Separation

Membrane technology offers solutions for separation of complex gas mixtures. Therefore, new efficient and durable membranes are required to produce gas permeation modules with high area/volume for CO₂ removal from natural gas. This study aims to develop cost-effective zeolite DD3R alumina composite hollow fibers to achieve these process requirements. A porous hollow fiber support from low-cost alumina was prepared via phase inversion followed by thermal treatment. DD3R zeolite seeds were then implanted over the surface of the microporous hollow fibers to form a selective layer by hydrothermal synthesis. The thickness of the selective layer was controlled by the seed concentration, which also affected the crystal intergrowth and competing zeolite phase formation, Sigma-2, which influenced the membrane performance. A reduced-diameter composite DD3R-alumina hollow fiber was obtained with a selectivity of 203 and a CO₂ permeance of 5.4 x 10^-8 mol m⁻² s⁻¹ Pa⁻¹ at a pressure of 2 bar.

Keywords:
DD3R zeolite membrane; Alumina Hollow fiber; CO₂-CH₄ separation; Molecular sieving