Carbon molecular sieve (CMS) membranes are inorganic membranes that can be easily prepared to separate gas components based on their molecular sizes. Supported CMS membranes are commonly fabricated by coating a precursor on a porous support followed by pyrolysis under inert conditions. However, the current availability of suitable porous supports is limited. Recently, a new porous carbon fiber (PCF), which can potentially be used as a support, has been prepared for commercialization. Thus, we herein report the preparation of CMS membranes supported on this new PCF using wood tar as the precursor. More specifically, the CMS membrane was formed on the outer surface of the PCF by dip-coating the wood tar solution (40, 60, 70, or 80 wt%) followed by pyrolysis at 600 °C. For comparison, CMS membranes supported on commercially available porous ceramic tubes (NA3) were also prepared under the same conditions. The morphologies of the CMS membranes were characterized by scanning electron microscopy. It was found that for both supports, the CMS membranes derived from the 70 wt% wood tar solution exhibited the optimum results for H2 separation, although the PCF-supported CMS membranes exhibited a higher gas permeance and selectivity than the NA3-supported membranes. Furthermore, a thinner layer of dense carbon was formed on the PCF than on the NA3 support. Overall, this study demonstrated that PCF can be used for supported CMS membranes, wherein the PCF-supported CMS membrane derived from the 70 wt% wood tar solution and pyrolyzed at 600 °C exhibited the highest H2 selectivity among the various membranes obtained over the pyrolysis temperature range of 500–700 °C. This membrane exhibited moderate H2/N2 and H2/CH4 selectivities of 155 and 340, respectively, with a H2 permeance of 86 GPU. Finally, our results show that wood tar is an attractive raw material for the preparation of CMS membrane precursors.
Owing to the advantages of rapid adsorption and desorption characteristics, excellent gas separation performance, as well as good thermal and chemical resistance, carbon molecular sieve (CMS) membranes have been developed as a promising gas separation tool. Over the past 30 years, hollow fiber carbon molecular sieve (HFCMS) membranes have become the preferred choice for industrial applications due to their high surface area-to-volume ratio and the ability to assemble lightweight membrane modules. The gas transport mechanism behind the HFCMS is dominated by molecular sieving function. They can be prepared by pyrolysis of the polymeric hollow fiber precursors. Post-treatments can tailor the ultramicropores structure to improve the separation performance. This paper aims to review the recent progress in the preparation of HFCMS membranes from aspects of precursor selection, pyrolysis conditions and post-treatment. Moreover, a brief perspective in terms of future investigation of HFCMS membrane is also proposed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.