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.

Modelling and prediction of toluene adsorption saturation basing on characteristic values of activated carbons.

Herein, the association between the dynamic adsorption capacity of toluene and several important characteristic values on activated carbon (AC) samples was investigated by multidimensional linear regression. Among the characteristic values, the carbon tetrachloride (CTC) adsorption value has demonstrated relatively stronger correlation with the toluene adsorption capacity on AC samples with diverse sources and forms, particularly in exposure to high-concentration toluene. Notably, the relevance of the toluene adsorption capacity to the CTC value could also be extended to a series of other porous adsorbents, which proved the wide applicability of CTC value in characterizing the adsorption behaviors.

The Reinforced Separation of Intractable Gas Mixtures by Using Porous Adsorbents.

This review focuses on the mechanism and driving force in the intractable gas separation using porous adsorbents. A variety of intractable mixtures have been discussed, including air separation, carbon capture, and hydrocarbon purification. Moreover, the separation systems are categorized according to distinctly biased modes depending on the minor differences in the kinetic diameter, dipole/quadruple moment, and polarizability of the adsorbates, or sorted by the varied separation occasions (e.

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.

Covalent Organic Frameworks with Ionic Liquid-Moieties (ILCOFs): Structures, Synthesis, and CO Conversion.

CO, an acidic gas, is usually emitted from the combustion of fossil fuels and leads to the formation of acid rain and greenhouse effects. CO can be used to produce kinds of value-added chemicals from a viewpoint based on carbon capture, utilization, and storage (CCUS). With the combination of unique structures and properties of ionic liquids (ILs) and covalent organic frameworks (COFs), covalent organic frameworks with ionic liquid-moieties (ILCOFs) have been developed as a kind of novel and efficient sorbent, catalyst, and electrolyte since 2016.

Tuning Functionalized Ionic Liquids for CO Capture.

The increasing concentration of CO in the atmosphere is related to global climate change. Carbon capture, utilization, and storage (CCUS) is an important technology to reduce CO emissions and to deal with global climate change. The development of new materials and technologies for efficient CO capture has received increasing attention among global researchers.

A Cooperative OSDA Blueprint for Highly Siliceous Faujasite Zeolite Catalysts with Enhanced Acidity Accessibility.

A cooperative OSDA strategy is demonstrated, leading to novel high-silica FAU zeolites with a large potential for disruptive acid catalysis. In bottom-up synthesis, the symbiosis of choline ion (Ch ) and 15-crown-5 (CE) was evidenced, in a form of full occupation of the sodalite (sod) cages with the trans Ch conformer, induced by the CE presence. CE itself occupied the supercages along with additional gauche Ch , but in synthesis without CE, no trans was found.

Rational Synthesis of Chabazite (CHA) Zeolites with Controlled Si/Al Ratio and Their CO /CH /N Adsorptive Separation Performances.

Separation of CO from CH and N is of great significance from the perspectives of energy production and environment protection. In this work, we report the rational synthesis of chabazite (CHA) zeolites with controlled Si/Al ratio by using N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdaOH) as an organic structure-directing agent, wherein the dependence of TMAdaOH consumption on the initial Si/Al ratio was investigated systematically. More TMAdaOH is required to direct the crystallization of CHA with higher Si/Al ratio.

Organic-Free, ZnO-Assisted Synthesis of Zeolite FAU with Tunable SiO /Al O Molar Ratio.

Zeolite FAU with tunable SiO /Al O molar ratio has been successfully synthesized in the absence of organic structure-directing agents (OSDA). Specifically, the addition of zinc species contributes to the feasible and effective adjustment of the framework SiO /Al O molar ratio between about 4 and 6 depending on the amount of zinc species added in the batch composition. In contrast, a typical OSDA such as tetramethylammonium hydroxide (TMAOH) has a limited effect on the SiO /Al O molar ratio of the zeolite.

Enhanced Trace Carbon Dioxide Capture on Heteroatom-Substituted RHO Zeolites under Humid Conditions.

Boron and copper heteroatoms were successfully incorporated into the frameworks of high-silica RHO zeolite by adopting a bulky alkali-metal-crown ether (AMCE) complex as the template. These heteroatom-doped zeolites show both larger micropore surface areas and volumes than those of their aluminosilicate analogue. Proton-type RHO zeolites were then applied for the separation of CO /CH /N mixtures, as these zeolites have weaker electric fields and, thus, lower heats of adsorption.

Targeted Synthesis of Ultrastable High-Silica RHO Zeolite Through Alkali Metal-Crown Ether Interaction.

High-silica RHO zeolite was directly synthesized using an alkali metal-crown ether (AMCE) complex as organic structure-directing agent (OSDA). Derived from the UV-vis spectra and zeolite patterns, the crown ether-cesium cation interaction was found to have crucial effect on the enhancement of silica content within the zeolite framework. The synthesized RHO zeolites possess up to four times larger silica/alumina ratio (SAR) values than that in their conventional form, which gives them extraordinarily rigid frameworks even after hydrothermal aging under 800 °C.