Cellulose-Based Carbon Molecular Sieve Membranes for Gas Separation: A Review

Abstract

In the field of gas separation and purification, membrane technologies compete with conventional purification processes on the basis of technical, economic and environmental factors. In this context, there is a growing interest in the development of carbon molecular sieve membranes (CMSM) due to their higher permeability and selectivity and higher stability in corrosive and high temperature environments. However, the industrial use of CMSM has been thus far hindered mostly by their relative instability in the presence of water vapor, present in a large number of process streams, as well as by the high cost of polymeric precursors such as polyimide. In this context, cellulosic precursors appear as very promising alternatives, especially targeting the production of CMSM for the separation of O2/N2 and CO2/CH4. For these two gas separations, cellulose-based CMSM have demonstrated performances well above the Robeson upper bound and above the performance of CMSM based on other polymeric precursors. Furthermore, cellulose is an inexpensive bio-renewable feed-stock highly abundant on Earth. This article reviews the major fabrication aspects of cellulose-based CMSM. Additionally, this article suggests a new tool to characterize the membrane performance, the Robeson Index. The Robeson Index, θ, is the ratio between the actual selectivity at the Robeson plot and the corresponding selectivity—for the same permeability—of the Robeson upper bound; the Robeson Index measures how far the actual point is from the upper bound.

Polypropylene Hollow Fiber Membrane by Dissolution-Inducing Pore Methods

“…The thin wall of the hollow fiber membrane is the functional layer that mainly blocks the liquid from passing through the gas. The thinner functional layer can reduce gas mass transfer resistance [ 45 ]. However, the separation layer here is thin, which induces a risk of water permeability.…”

Overview of Membrane Science and Technology in Portugal

“…200 • C). Potential applications include carbon dioxide removal from natural gas/biogas streams, hydrogen recovery from streams with light hydrocarbons, light olefins/paraffins separation, xenon recovery and air separation, among others [220]. Mendes' group pioneered in Portugal the development of CMS membrane technology through the work of Lagorsse et al [62,63], who studied the transport mechanism and the ageing effect of the CMS membranes modules produced by Carbon Membranes Ltd., an Israeli company in this field.…”

Membranes Targeting Industrial O2 Production from Air – A Short Review

“…Future examination of more mixtures, having as constituents various ILs and highly O 2 -selective PFCs, could reveal that enhanced permeance combined with very high selectivity is possible. Other high selectivity membranes, but with very low O 2 permeance, are carbon molecular sieve membranes (CMSMs), such as cellulose-based CMSMs with very high O 2 /N 2 selectivities, up to 800 [54], or polyimide-derived CMSMs [55,56] and PIM-PIderived CMSMs [57], as is summed up in the review of Wang et al [47]. Such membranes could gain prospects to become usable in applications only if the selective layer thickness is significantly reduced, below 1.5 µm, as was achieved in the aforementioned work of Lee et al [46].…”