Design of a Tunable, High-performance Mixed Matrix Membrane Platform for Gas Separations.

Membrane technology offers substantial economic and environmental benefits for energy-intensive chemical separations. Chabazite-type zeolite, possessing a 3-D channel system with molecular-sieving windows, can be an ideal membrane material, but conditions to synthesize zeolite-only membranes limit optimization strategies. Guided by advanced quantum chemistry calculations on inner-pore molecular interactions, zeolite properties are tailored for different separations and optimized particles incorporated in polyimide at very high loadings.

Split Syntheses: Introducing Bottom-Up Control over Aluminum in SSZ-13 and ZSM-5 Zeolites.

Zeolite synthesis is known as a difficult-to-control process, with many degrees of freedom that have a partially uncharted impact on the final product. Due to this, many zeolite scientists have regarded the initial mixing (aging) stage as the only time at which the chemical composition of a zeolite synthesis mixture can be impacted without heavily disrupting the delicate equilibria that are at play during crystallization. Recently, however, this view has started to change, with innovative techniques such as charge density mismatch or electro-assisted synthesis showing that the addition of new elements to the reactor midsynthesis might lead to new and surprising outcomes.

Enhancing the Acidity Window of Zeolites by Low-Temperature Template Oxidation with Ozone.

Revisiting the impact of the first and often deemed trivial postsynthetic step, i.e., a high-temperature oxidative calcination to remove organic templates, increases our understanding of thermal acid site evolution and Al distributions.

Truly combining the advantages of polymeric and zeolite membranes for gas separations.

Mixed-matrix membranes (MMMs) have been investigated to render energy-intensive separations more efficiently by combining the selectivity and permeability performance, robustness, and nonaging properties of the filler with the easy processing, handling, and scaling up of the polymer. However, truly combining all in one single material has proven very challenging. In this work, we filled a commercial polyimide with ultrahigh loadings of a high-aspect ratio, CO-philic Na-SSZ-39 zeolite with a three-dimensional channel system that precisely separates gas molecules.