High‐Flux Carbon Molecular Sieve Membranes for Gas Separation

Abstract

Carbon membranes have great potential for highly selective and cost-efficient gas separation. Carbon is chemically stable and it is relative cheap. The controlled carbonization of a polymer coating on a porous ceramic support provides a 3D carbon material with molecular sieving permeation performance. The carbonization of the polymer blend gives turbostratic carbon domains of randomly stacked together sp hybridized carbon sheets as well as sp hybridized amorphous carbon. In the evaluation of the carbon molecular sieve membrane, hydrogen could be separated from propane with a selectivity of 10 000 with a hydrogen permeance of 5 m (STP)/(m hbar). Furthermore, by a post-synthesis oxidative treatment, the permeation fluxes are increased by widening the pores, and the molecular sieve carbon membrane is transformed from a molecular sieve carbon into a selective surface flow carbon membrane with adsorption controlled performance and becomes selective for carbon dioxide.

Carbon Molecular Sieve Membrane Preparation by Economical Coating and Pyrolysis of Porous Polymer Hollow Fibers

“…[3] Carbon molecular sieve (CMS) membranes [4] show separation performance surpassing the polymeric upper bound [4b] for gas pairs such as O 2 /N 2 ,C O 2 / CH 4 ,C 2 H 4 /C 2 H 6 . [5] Fori ndustrial applications,t ranslation of such performance into high-efficiencyh ollow fiber configurations is important for space and weight savings.U nfortunately,p olyimides (for example,6 FDA: BPDA-DAM, [6] 6FDA-6FpDA, [7] 6FDA: BTDA-DAM [8] )for CMS membrane fabrication are expensive.M aterial cost to prepare CMS membranes can be reduced by using al ow-cost material to fabricate ap orous support membrane,w hich can be coated with the expensive high-performance polymers.T his fact notwithstanding,i ti sc hallenging to coat at hin defect-free layer on the precursor fiber, which on pyrolysis would lead to aC MS membrane with attractive separation performance.…”

An Extrinsic‐Pore‐Containing Molecular Sieve Film: A Robust, High‐Throughput Membrane Filter

“…As the current synthetic protocol is not optimized yet, additional, parametric studies (seed layer density, calcination temperature, secondary growth durations/compositions) will follow primarily to further improve the separation performance of hierarchically structured MFI membranes. Furthermore, the use of high flux supports [8a, 27] will be effective for increasing the p ‐xylene molar fluxes through the HM membrane (Supporting Information, Subsection S2.7) to be industrially attractive.…”

A Review on Polymer Precursors of Carbon Molecular Sieve Membranes for Olefin/Paraffin Separation

“…CMS membranes consists of a rigid and amorphous structure with small pore size distribution [ 76 , 77 ]. The pore structure of a CMS membrane has ultramicropores (0.3–0.5 nm), which allow molecular-sieving separation.…”