Carbon hollow fiber membranes for a molecular sieve with precise-cutoff ultramicropores for superior hydrogen separation

Abstract

Carbon molecular sieve (CMS) membranes with rigid and uniform pore structures are ideal candidates for high temperature- and pressure-demanded separations, such as hydrogen purification from the steam methane reforming process. Here, we report a facile and scalable method for the fabrication of cellulose-based asymmetric carbon hollow fiber membranes (CHFMs) with ultramicropores of 3–4 Å for superior H2 separation. The membrane fabrication process does not require complex pretreatments to avoid pore collapse before the carbonization of cellulose precursors. A H2/CO2 selectivity of 83.9 at 130 °C (H2/N2 selectivity of >800, H2/CH4 selectivity of >5700) demonstrates that the membrane provides a precise cutoff to discriminate between small gas molecules (H2) and larger gas molecules. In addition, the membrane exhibits superior mixed gas separation performances combined with water vapor- and high pressure-resistant stability. The present approach for the fabrication of high-performance CMS membranes derived from cellulose precursors opens a new avenue for H2-related separations.

In Situ Derived Hybrid Carbon Molecular Sieve Membranes with Tailored Ultramicroporosity for Efficient Gas Separation

“…The hardness and Young's modulus obtained from loaddisplacement curves of nanoindentation tests show that the HCMS membranes possess substantially improved mechanical properties compared to the CMS membranes prepared at the same pyrolysis temperature (Figure 1f and Figure S5, Supporting Information). [33] The results verify the good compatibility between the two carbonized phases in the HCMS membranes, ensuring their practical use with excellent mechanical robustness.…”

“…Above 550 °C, the weight loss becomes less pronounced, and further temperature increases typically induce a more ordered carbonaceous structure in the resulting CMS and HCMS membranes. [7,32,33] In this study, CMS membranes from the pure 6FDA-DAM precursor are denoted as CMS-OOO, while those from the UiO-66-NH 2 (20 wt%)/6FDA-DAM MMM precursor are shown as HCMS-OOO, and pyrolyzed UiO-66-NH 2 nanoparticles are named UiO-OOO. Here, OOO indicates the pyrolysis temperature at the isotherm stage (550, 700, and 800 °C).…”

“…During the isotherm stage at 700 °C, no additional MS peaks were detected for both UiO-66-NH 2 and 6FDA-DAM cases due to the termination of the carbonization process, which is consistent with the previous reports. [8,33,42] In stark contrast, the MMM precursor exhibited two distinct carbonization behaviors from those of each filler and matrix as a single phase (highlighted blue areas). (1) At the heating step above 400 °C, the MMM only showed a gradual increase in CO 2 evolution, while a noticeable CO 2 peak was observed for UiO-66-NH 2 .…”

Structural design and mechanism analysis of hierarchical porous carbon fibers for advanced energy and environmental applications

“…Recently, Lei et al reported the fabrication of cellulose-based porous carbon hollow fibers. 127 By tuning the coagulation temperature of the microcrystalline cellulose/ionic liquid/water system, the obtained carbon fibers exhibited an asymmetric structural morphology throughout their body, including a porous inner layer, a middle layer rich in macrovoids and a dense outer layer. By controlling the conversion of sp 3 to sp 2 hybridized carbon via different the carbonisation temperature, finely tuned ultramicropores were achieved in the dense outer layer of the PCF (Fig.…”

Highly Permeable Mixed Matrix Hollow Fiber Membrane as a Latent Route for Hydrogen Purification from Hydrocarbons/Carbon Dioxide

“…Undoubtedly, faced with the threats of depletion of petrochemical resource, catastrophic extreme weather, and burgeoning energy demand, all countries are driven to seek for renewable resources for sustainable development [1]. Among a variety of sustainable resources known to date, hydrogen is a compelling one, because of its high heating value and zero-carbon emission.…”