New zeolite design could cut costs of separating natural gas
Researchers have engineered a zeolite material that uses molecular-scale trapdoors to filter methane from CO2, potentially improving the efficiency of natural gas processing. The technique could reduce separation costs for energy companies and support carbon capture operations, where isolating methane from mixed gas streams remains a significant operational expense.
Originaltitel: Molecular trapdoor-driven sieving of CO2/CH4 in ABW zeolites
<p>Achieving sieving-level CO2/CH4 separation has long been a challenge due to the difficulty of precise pore size control in porous materials to distinguish molecules with minimal size difference. In this study, we present 1D channel-type zeolites, namely ABW zeolites, which leverage the molecular trapdoor effect to achieve high CO2/ CH4 selectivity. By substituting the extraframework Li+ with divalent Mg2+ and Ni2+, CO2 molecules gain increased access to the internal void spaces of ABW 1D channels, while CH4 molecules are excluded. Excelling in kinetic analysis, binary breakthrough experiments, and high-pressure isothermal adsorption measurements underscores the potential for practical separation applications. The mechanism of sieving-level separation and the thermal framework transformation are elucidated through a combination of varying temperature adsorption isotherms and in-situ synchrotron powder X-ray diffraction. Our work introduces a novel approach to discriminate CO2 from CH4 for biogas upgrading, providing an energy-efficient alternative to conventional techniques such as membrane separation and amine scrubbing.</p>