Highly Structured Nanofiber Zeolite Materials for Biogas Upgrading

Abstract

Hierarchical zeolite composite nanofibers are designed using an electrospinning technique with post‐carbonization processing to form mechanically strong pellets for biogas upgrading. A ZSM‐5 nanopowder (zeolite) and a polyvinylpyrrolidone (PVP) polymer are electrospun to form ZSM/PVP composite nanofibers, which are transformed into a ZSM and carbon composite nanofiber (ZSM/C) by a two‐step heat treatment. The ZSM/C nanofibers show a 30.4% increase in Brunauer–Emmett–Teller (BET) surface area compared with the non‐structured ZSM‐5 nanopowder. Using ideal adsorbed solution theory, CO2‐over‐CH4 selectivity of 20 and CO2 uptake of 2.15 mmolg−1 at 293 K at 1 bar for ZSM/C nanofibers are obtained. For the efficient use of adsorbents in pressure swing adsorption operation, the nanofibers are structured into ZSM/C pellets that offer a maximum tensile strength of 6.46 MPa to withstand pressure swings. In the breakthrough tests, the CO2 uptake of the pellets reach 3.18 mmolg−1 at 293 K at 4 bar after 5 breakthrough adsorption–desorption cycles, with a much higher mass transfer coefficient of 1.24 ms−1 and CO2 uptake rate of 2.4 mg of CO2 g−1s−1, as compared with other structured zeolite adsorbents.

Shaping 90 wt% NanoMOFs into Robust Multifunctional Aerogels Using Tailored Bio‐Based Nanofibrils

“…The mass transfer coefficient (k) was calculated to be 0.3 m s −1 (Table S9, Supporting Information) by modeling the breakthrough data following previous work. [38] This value is similar to that of structured freeze-cast zeolite A monoliths (k = 0.3 m s −1 ) with lamellar pores. [38,39] These results also indicate that, by forming a structured anisotropic material, the aerogels can be beneficially utilized for industrial gas adsorption and separation applications with very low pressure loss.…”

“…[ 38 ] This value is similar to that of structured freeze‐cast zeolite A monoliths ( k = 0.3 m s −1 ) with lamellar pores. [ 38,39 ] These results also indicate that, by forming a structured anisotropic material, the aerogels can be beneficially utilized for industrial gas adsorption and separation applications with very low pressure loss.…”

A phase conversion method to anchor ZIF-8 onto a PAN nanofiber surface for CO2 capture

“…into nanofibers to enhance gas transport, 17 adsorption capacity 18 and adsorption kinetics. 19 For example, zeolite nanofibers of ZSM-5 have been fabricated by electrospinning, post shaping and carbonization of polyvinylpyrrolidone (PVP) 20 the performance has been evaluated for CO 2 separation from CO 2 /CH 4 mixtures in synthetic biogas mixtures.…”

Colloidal Stabilization of Submicron-Sized Zeolite NaA in Ethanol–Water Mixtures for Nanostructuring into Thin Films and Nanofibers

“…As zeolite powders cannot be used as such, they are shaped into functional forms. Various shaping approaches are explored, such as in situ growth, , seeded growth, gel-based deposition, slurry-based wet deposition, − and complex shaping methods, such as electrospinning, − additive manufacturing, − etc. In the mentioned approaches, the colloidal zeolite suspensions are either deposited on substrates or used as an ink for the shaping.…”