Graduate Defense: Naqsh Mansoor

Dissertation Information

Title:  Flow Electrode Capacitive Deionization using MXene Suspension Electrodes for Energy Efficient Water Remediation

Program: Doctor of Philosophy in Materials Science and Engineering

Advisor: Dr. David Estrada, Materials Science and Engineering and Electrical and Computer Engineering

Committee Members: Dr. Claire Xiong, Materials Science and Engineering; Dr. Brian Jaques, Materials Science and Engineering; and Dr. Luis. A Diaz Aldana, Materials Science and Engineering

Abstract

The energy-water nexus poses an integrated research challenge with crucial global implications. Wastewater generated as a result of anthropogenic activities is treated with energy intensive remediation processes like ion exchange, reverse osmosis, and chemical precipitation. In this context, it is imperative to develop and implement an energy efficient water remediation technology that will positively impact the energy-water nexus. Capacitive deionization (CDI) is a separation technology that electrophoretically removes ions from water by applying a small voltage below the dissociation potential of water (1.23 V). The ions are temporarily stored in the electrodes. In the absence or reversal of the applied potential, the ions are released back into the stream. This makes CDI ideal for both removal and recovery. A CDI system can have various cell architectures but flow electrode capacitive deionization (FE-CDI) has been proven advantageous because of its ability to prevent cross contamination, and to run in uninterrupted cycles ad infinitum. The performance of FE-CDI system relies on the selection of suitable electrode materials with desired properties of high electrical conductivity, high surface area, colloidal stability, and surface sensitivity. MXenes are an emerging class of two-dimensional (2D) materials that are highly conductive, hydrophilic, tunable, and possess attractive charge storage and ion transport properties. Titanium Carbide MXene was the first one to be discovered and serves as a model system for scientific investigation of physical properties and applications of MXenes. In this work, we lay the groundwork necessary to pioneer a foundational understanding of the interplay between the physical and chemical properties of MXenes, and the electrochemical kinetics of their solid – liquid interactions. This fundamental understanding of the structure-property-processing correlation will enable the design of a flow electrode capacitive deionization system (FE-CDI) tailored for high charge efficiency and ion removal capacity of various pollutant ions of interest.