Integration of redox-electrosorption and redox-electrodialysis for water remediation, waste valorization, and organic species separations

Kim, Nayeong

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https://hdl.handle.net/2142/129697 Copy

Description

Title

Integration of redox-electrosorption and redox-electrodialysis for water remediation, waste valorization, and organic species separations

Author(s)

Kim, Nayeong

Issue Date

2025-04-22

Director of Research (if dissertation) or Advisor (if thesis)

Su, Xiso

Doctoral Committee Chair(s)

Su, Xiso

Committee Member(s)

• Rao, Christopher V
• Zhao, Huimin
• Gewirth, Andrew A

Department of Study

Chemical & Biomolecular Engr

Discipline

Chemical Engineering

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Electrochemical separations, Redox polymer, Water Remediation, Resource recovery

Abstract

Efficient and selective molecular separation is a grand challenge across chemical, biomanufacturing, and environmental sectors—accounting for the major fraction of global industrial energy use. Here, this dissertation develops and integrates electrochemical platforms for selective separation based on redox-mediated electrosorption and electrodialysis, advancing sustainable solutions for water remediation, resource recovery, and organic species purification. Central to this work is the design of redox-active polymers, selective membranes, and electrochemical architectures to tailor for specific binding interactions and electrochemical control. The tailored design of redox-active polymers—capable of varied non-covalent bonding interactions such as hydrogen bonding, halogen bonding, and crown ether coordination—provides a path forward for a more selective, energy-efficient separation heterogeneous platform. Optimizing system components—membranes, redox species, and operating conditions—expanded the applicability of redox-mediated electrodialysis to biomolecule separations, which are particularly sensitive to degradation and fouling. Taken together, this thesis is organized around the advancement of (i) electrosorption technologies, (ii) redox-mediated electrodialysis systems, (iii) the integration of these approaches and the incorporation of diverse intermolecular interactions, and (iv) forward-looking strategies to enhance selectivity and broaden the applicability of electrochemical separation platforms. Electrosorption in non-aqueous media using halogen bonding (Chapters 2–3) is the first part of the thesis that introduces halogen bonding as a novel, redox-responsive non-covalent interaction for molecular separations. In Chapter 2, redox-active metallopolymers are synthesized to enable selective halide capture in organic solvents. In Chapter 3, copolymerization strategies tailor the conformational dynamics of halogen bonding motifs, enabling separation among structurally similar organohalides. The copolymer design switches the binding mode between bidentate and monodentate, offering a molecular handle to fine-tune selectivity in complex organic separations. Chapter 4 integrates redox-active polymer electrosorption with the bipolar electrochemistry concept, enabling membraneless, simultaneous multicomponent separation in a heterogeneous platform. This wireless configuration allows spatially discrete oxidation and reduction reactions, offering a scalable platform for treating complex wastewater streams and conducting multiplexed separations without external wiring or extensive electrode patterning. Chapters 5-7 discuss redox-mediated electrodialysis for protein valorization and organic pollutant removal (Chapters 5–7), focusing on redox-mediated electrodialysis for size- and charge-selective separations. Chapter 5 investigates the valorization of whey proteins, using redox-ED, while Chapter 6 replaces conventional ion-exchange membranes with nanofiltration membranes by leveraging water-soluble redox polymers, enabling the removal of organic without membrane fouling. Chapter 7 modifies membranes with polyelectrolyte layer-by-layer coatings to achieve preferential recovery of organic acids (e.g., succinic acid) over smaller competing anions like chloride. Chapters 8–10 demonstrate that coupling electrosorption with ion migration enhances selectivity for the removal of persistent contaminants such as PFAS and the recovery of valuable ions like lithium. Chapter 8 targets PFAS compounds of varying chain lengths, showing broad-spectrum removal in a single-stage system by simultaneous electrosorption and upconcentration. Chapter 9 uses lithium manganese oxide absorbents in a redox-ED configuration for selective lithium recovery from brines by leveraging size-exclusive absorption and ion migration. In Chapter 10, redox-active copolymers incorporating 12-crown-4 ether ligands are used to extract lithium from spent lithium-ion batteries, with electrochemically-driven release of bound lithium by redox-induced electrostatic repulsion, offering an environmentally benign lithium uptake and release from spent-lithium-ion batteries. Finally, Chapter 11 outlines emerging opportunities in electrochemical separations by (i) highlighting the need for deeper insights into binding interactions through multiscale modeling and advanced analytical techniques, (ii) advancing strategies for multicomponent separations, and (iii) exploring unexplored molecular interactions, including chemical conversions, to broaden applications to dehydration and dehumidification processes. These strategies can further expand the capabilities of electrochemical platforms, particularly when powered by renewable electricity and implemented in modular or decentralized settings. Overall, this dissertation establishes foundational frameworks for electrochemical separation systems that are selective, sustainable, and adaptable. By innovating at the intersection of polymer chemistry, materials science, and electrochemical engineering, this work contributes to next-generation separation technologies. The design principles and system architecture presented here pave the way for electrified processes in environmental engineering, clean energy, and sustainable chemical manufacturing.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129697

Copyright and License Information

Copyright 2025 Nayeong Kim

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