Electronic Theses and Dissertations

Date of Award

1-1-2024

Document Type

Thesis

Degree Name

M.S. in Engineering Science

First Advisor

Sasan Nouranian

Second Advisor

Byron Villacorta

Third Advisor

Matteo D'Alessio

School

University of Mississippi

Relational Format

dissertation/thesis

Abstract

Polyetherimide (PEI) ultrafiltration membranes were created and evaluated for their ability to separate bovine serum albumin (BSA) from water using two fabrication methods: nonsolvent induced phase separation (NIPS) and vapor-induced phase separation (VIPS). In the NIPS method, membranes were made with varying amounts of Pluronic® P-123 and with or without graphene nanoplatelets (GNPs). The membrane with 1 wt.% Pluronic® P-123 exhibited the best performance, achieving a pure water flux (PWF) of 355 L m-2 h-1 (LMH) and a rejection rate of 90.9%. Adding 1 wt.% GNPs to this system further improved performance, resulting in a PWF of 747 LMH and a rejection rate of 97.5%. For the VIPS method, membranes were made with the same optimal NIPS composition (1 wt.% Pluronic® P-123, no GNPs) to assess the impact of vapor exposure time and relative humidity during fabrication. Longer vapor exposure times reduced PWF but increased rejection, whereas higher relative humidity increased PWF but decreased rejection. The NIPS samples had a porous finger-like morphology, while VIPS membranes showed a symmetric cellular structure at low vapor exposure times, transitioning to a bi-continuous morphology with longer exposure. The optimal VIPS membrane was achieved with a 30-minute vapor exposure time and 65% relative humidity, yielding a PWF of 49 LMH and a rejection rate of 55%. Comparing the two methods, NIPS demonstrated higher flux and rejection rates, making it more suitable for BSA separation from water using PEI membranes.

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