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Date Available
5-5-2026
Year of Publication
2026
Document Type
Master's Thesis
Degree Name
Master of Science in Chemical Engineering (MSChE)
College
Engineering
Department/School/Program
Chemical Engineering
Faculty
Isabel C. Escobar
Faculty
Zach J. Hilt
Abstract
The growing global demand for clean drinking water has intensified the need for advanced water treatment technologies capable of efficiently removing contaminants while maintaining environmental sustainability. Polymeric membrane systems have emerged as an effective approach for water separations due to their high separation efficiency, simplicity, and adaptability to a wide range of water treatment applications. However, traditional membrane fabrication processes often rely on toxic organic solvents, such as N-methyl-2-pyrrolidone (NMP) and diemethylacetamide (DMAc), which pose environmental and health risks. These concerns have led to an increase in regulatory restrictions, primarily through the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) organization. Eco-friendly solvents have been investigated as an alternative to traditional toxic solvents. This study investigates the fabrication and performance of polymeric membranes using eco-friendly solvent systems, with a focus on bilayer membranes design to improve separation performance over traditional single-layer membranes. Membranes were fabricated using eco-friendly solvents, Rhodiasolv© PolarClean and gamma-valerolactone in combination with polymers polysulfone (PSf) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Membranes were fabricated using non-solvent induced phase separation (NIPS) through doctor blade extrusion (DBE) and slot-die coating (SDC) methods in order to compare traditional laboratory-scale casting methods (DBE) with scalable fabrication techniques (SDC). Bilayer membranes were found to overcome the inherent limitations presented by single-layer membranes, such as mechanical stability, with polydopamine (PDA) being incorporated as an adhesion-promoting additive to enhance bonding between polymer layers. Membrane characterization included scanning electron microscopy (SEM), contact angle measurements, and tensile strength tests, along with permeability and solute rejection tests to investigate membrane performance. Results showed that membranes fabricated at higher concentrations and through the SDC method performed at a higher level than the other membranes, exhibiting improved solute rejection rates (68% rejection of divalent ions and 97% rejection of proteins) and less variability in pore structure distribution.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2026.108
Archival?
Archival
Funding Information
This study was supported by the National Science Foundation under grant number NSF 3200004539 from 2024-2026. The content is solely the responsibility of the authors and does not necessarily represent the views of the National Science Foundation.
Recommended Citation
Kulshrestha, Eesh M., "ECO-FRIENDLY SOLVENT-BASED FABRICATION OF SINGLE-LAYER AND POLYDOPAMINE-MODIFIED BILAYER PVDF-HFP MEMBRANES" (2026). Theses and Dissertations--Chemical and Materials Engineering. 189.
https://uknowledge.uky.edu/cme_etds/189
