Masters Theses

Date of Award

8-2025

Degree Type

Thesis

Degree Name

Master of Science

Major

Chemistry

Major Professor

Sheng Dai

Committee Members

Ziying Lei, Bahvya Sharma, Shannon Mahurin

Abstract

With a constant rise in carbon emissions, developing effective gas separation techniques for carbon capture is critical for combating climate change. Type III porous liquids represent a promising new class of porous material that combines the free volume of porous solids and the nonvolatile properties of ionic liquids. The resulting permanent porosity can be used to adjust the gas separation properties of an ionic liquid, including the 𝐢𝑂2/𝑁2 selectivity and CO2 and N2 permeabilities. In this project, the zeolites Hydrogen-Zeolite Socony Mobil-5 (H-ZSM-5) and Sodium-Zeolite Socony Mobil-5 (Na-ZSM-5) were suspended in the ionic liquids, Trihexyltetradecylphosphonium bromide ([P66614][Br]) and 8,8β€²-(3,6-dioxaoctane-1,8-diyl)bis(1,8- diazabicyclo[5.4.0]undec-7-en-8-ium)bis(trifluoromethanesulfonyl)imide ([DBU-PEG][NTf2]) respectively. The membranes of the ionic liquids and their porous liquids at varying concentrations were tested and analyzed for their 𝐢𝑂2/𝑁2 selectivity and their CO2 and N2 permeabilities. The goal of this work is to understand the gas transport in porous liquids, explore how the addition of zeolites impacts gas separation of an ionic liquid, and assess how varying the concentration of free volume in the porous liquids influences gas separation performance. The results show that incorporating H-ZSM-5 with [P66614][Br] enhances the 𝐢𝑂2/𝑁2 selectivity as well as the CO2 and N2 permeabilities as the zeolite concentration increases. The addition of Na-ZSM-5 in [DBU-PEG][NTf2] improved the 𝐢𝑂2/𝑁2 selectivity but led to a decrease in CO2 and N2 permeabilities. These results demonstrate that the addition of zeolites into ionic liquids can be used to adjust gas separation properties for carbon capture.

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