Pore modification of deca-dodecasil-rhombohedral zeolite membrane by carbon loading from in situ decomposition of 1-adamantanamine for improved gas separation

Abstract

A simple method of pore modification coupled with the removal of surface defects of a deca-dodecasil-rhombohedral (DDR) zeolite membrane has been developed via carbon (C) deposition. Carbon deposition was achieved by controlled decomposition of the structure-directing agent (SDA), 1-adamantanamine (1-ADA), into the membrane pore surface. Membranes that were synthesized with and without pore modification were characterized by thermal analysis, X-ray diffraction analysis, infrared spectroscopy, transmission electron microscopy, and Raman spectroscopy. Finally, the performance of the membranes was evaluated by permeance studies. The non-wetting characteristics of C had imparted hydrophobicity to the membrane pores, leading to enhanced permeability of the gas mixture. Modified membranes were shown to offer a relatively high hydrogen permeance of 13.47 × 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹. The selectivity of H₂/CO₂ was 4.9 based on single gas permeation and the separation factor increased to 8.5 for a H₂–CO₂ gas mixture at room temperature. In the light of these findings, the current technique is proposed to be useful for making a defect-free C-loaded membrane in a single step with high separation selectivity and permeability in tandem. This is the novelty that was achieved.