Date Available
5-12-2026
Year of Publication
2025
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Engineering
Department/School/Program
Chemical and Materials Engineering
Faculty
Isabel Escobar
Faculty
Zach Hilt
Abstract
Polymeric membranes have become a prominent technology applied in water filtration due to the lower cost, energy input, and simpler manufacturing process relative to other separation technologies. However, the environmental impact of polymeric membrane fabrication remains a hindrance due to the use of hazardous solvents derived from fossil fuels (e.g., DMAc, NMP, DMF) that pose a risk to the environment and human health. Whereas recent studies have demonstrated the proof-of-concept of polymeric membrane derived from eco-friendly solvents, the next steps of optimizing and upscaling the production of these membranes remains understudied and a gap between lab-scale studies and the path to commercial production. This thesis examines the performance optimization of polysulfone (PSf) membranes produced using the eco-friendly solvents Rhodiasolv® PolarClean and gamma-valerolactone (GVL) through the modification of the evaporation time step during the membrane casting process, which influences the rate of phase inversion and membrane pore formation. To scale the production of PSf-PolarClean-GVL membranes, samples were produced using the slot die coating (SDC) process, which can be integrated onto a roll-to-roll system for continuous film casting. Comparison studies of membrane samples fabricated via SDC and lab-scale doctor blade extrusion (DBE) found similar pore morphologies, mean pore size, total porosity, water permeance, and solute rejection, validating the use of SDC to produce scalable PSf membranes with eco-friendly solvents. Finally, the environmental and health impacts of the upscaled membrane fabrication process was evaluated by developing and completing a life cycle assessment (LCA), comparing the impact magnitudes between SDC and DBE, as well as substituting conventional solvents with PolarClean and GVL. Focusing on a “cradle-to-gate” system, the LCA found increased impacts when PolarClean and GVL were the selected solvents and material inputs for SDC to influence the impact magnitudes. Uncertainty and sensitivity analyses focusing on the role of electricity source and dope solution volume used in the fabrication process were conducted to strengthen the overall assessment. On a larger scale, these investigations highlight the potential materials and methods to advance the understanding and development of polymeric membranes with eco-friendly solvents to improve the technology’s sustainability.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.57
Funding Information
This study was supported by the National Science Foundation (grant no. NSF 2121674) from 2020-2025
This study was supported by the National Science Foundation (grant no. NSF NRT 1922694) from 2020-2025
This study was supported by the American Membrane Technology Association Reclamation Fellowship on Membrane Technology in 2023.
Recommended Citation
Lu, David, "The Optimization and Manufacturing Scale-Up of Polymeric Membranes Using Eco-Friendly Solvents" (2025). Theses and Dissertations--Chemical and Materials Engineering. 173.
https://uknowledge.uky.edu/cme_etds/173
