Date of Graduation

12-2014

Document Type

Thesis

Degree Name

Master of Science in Chemical Engineering (MSChE)

Degree Level

Graduate

Department

Chemical Engineering

Advisor/Mentor

Wickramasinghe, S. Ranil

Committee Member

Qian, Xianghong

Second Committee Member

Millett, Paul C.

Third Committee Member

Ulbricht, Mathias

Keywords

Concentration Polarization; Membranes; Responsive Polymers; Ultrafiltration

Abstract

Ultrafiltration (UF) membranes developed out of a need for protein separation processes. Currently, they are used in a variety of industries ranging from food manufacturing to pharmaceuticals for two main purposes: concentration, separation, and buffer exchange. UF membrane processes in product streams undergo frequent use and like all membrane processes experience a gradual decline in performance due to fouling phenomena both irreversible and reversible. Ultimately, performance declines to a point where the UF membrane needs to be replaced. Frequent replacement of UF membranes is detrimental to major industries that require high product throughput using UF processes. Thus, it is important to try and overcome any type of fouling to reduce the decline in UF membrane performance and thereby limit the frequency of UF replacement. One of the novel ways to do this is to design membranes that respond to changes in their environment or “responsive” membranes. Magnetically responsive membranes are a small emerging subset of the investigations in this field. The work in this thesis attempts to expand the knowledge of magnetically responsive membranes and apply it to UF membranes. Successful surface modification with magnetite (Fe3O4) nanoparticle capped poly(hydroxyl ethyl methacrylate) chains of UF regenerated cellulose membranes was confirmed by atomic force microscopy (AFM) and X-ray photospectroscopy (XPS) surface characterization methods. However, measuring the responsive nature of modified UF membranes resulted in inconclusive results. Possible reasons include the chemical modification method with regards to polymer chain density and length, reducing possible oxidation for reaction control, and addressing multiple amine attachment sites on the nanoparticle. Further investigations and studies are needed moving forward.

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