A high-permeance supported carbon molecular sieve membrane fabricated by plasma-enhanced chemical vapor deposition followed by carbonization for CO2 capture

We proposed a novel method of combining plasma enhanced chemical vapor deposition and carbonization to fabricate supported carbon molecular sieve (CMS) membranes. It proved to be more efficient than the traditional technique of repeated cycles of spin coating and carbonization. The effect of carbonization temperature on the membrane physical morphology, chemical structure, and separation performance was investigated. Results showed that the carbonized membranes were defect free, as characterized by both scanning electron microscopy and positron annihilation lifetime spectroscopy, despite the reduced membrane selective layer thickness at high carbonization temperatures. Raman and X-ray photoelectron spectroscopy demonstrated that the CMS membranes carbonized at high temperatures consisted of a graphite like structure. As such, their gas separation performance was enhanced compared with the precursor membrane, particularly the permeance. The supported CMS membrane obtained at a carbonization temperature of 500 degrees C gave the following gas separation performance: CO2 permeance=772.1 GPU. CO2/N-2 selectivity =14.3; O-2 permeance=150.6 GPU, and O-2/N-2 selectivity= 2.8. (C) 2014 Elsevier BM. All rights reserved.