Chemical and Biomolecular Engineering
Faculty Advisor: Casey O'Brien
Annual 2020 Project: Development of an Operando Spectroscopic Tool for Studying the Structure and Dynamics of Membranes in Complex Environments
Society depends on chemical separations for many basic necessities, including clean water, chemical products, medicines, fuels, and food. However, most industrial chemical separations are performed using thermal techniques, such as distillation, which consume an enormous amount of energy: about 10-15% of the world’s total energy consumption. Advanced membrane technologies that can efficiently separate chemicals have the potential to reduce the energy intensity of chemical separations by ~90%, which would have a substantial global impact. However, development of high-performance membranes is hindered by limited understanding of the fundamental molecular-scale processes that determine membrane performance, especially in complex environments. In this research project, the O’Brien group aims to address this knowledge gap by developing and testing a new operando spectroscopic tool that will probe the chemical structure and dynamics of membranes in complex environments. While operando spectroscopy is a well-established approach in catalysis, it has not been widely adopted by other fields, including membrane science. PI O’Brien is the first to apply operando spectroscopy to gas separation membranes, and his group has already developed a successful operando spectroscopy tool that simultaneously measures hydrogen permeation rates and surface-adsorbed species across dense metal membranes. This project’s goal is to develop a similarly effective but more versatile tool that can be used to study a diverse range of membrane separation systems (polymer, ceramic, metal; gas or liquid mixtures) using various types of spectroscopy, potentially greatly impacting the entire membrane science field. The overarching goals of the research project are to develop a new operando spectroscopic tool and demonstrate that this tool can provide unique information about the structure and dynamics of membranes under realistic and complex operation conditions. To achieve this goal, a new spectroscopic permeation cell will be built, and the tool will be constructed by combining the permeation cell with a Raman spectrometer, mass flow controllers, and a gas chromatograph in order to monitor the chemical structure of the membrane and solute permeation rates simultaneously. The tool will be used to monitor the chemical reactions occurring in polyvinylamine (PVam) facilitated transport membranes under simulated industrial conditions during the transport of carbon dioxide across the membrane. The mechanism occurring in these membranes is not well-understood, so a specific goal of the project in this application is to use the new tool to identify the intermediate species in the PVam-CO2 reaction and thus clarify the mechanism of CO2 transport. As a result, both the behavior of these commonly used membranes will be elucidated and the spectroscopy tool’s ability to analyze such membranes will be proven.