Date of Graduation

12-2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Materials Science & Engineering (PhD)

Degree Level

Graduate

Department

Materials Science & Engineering

Advisor/Mentor

Wickramasinghe, Ranil

Committee Member

Hestekin, Jamie

Second Committee Member

Kohanek, Julia

Third Committee Member

Edwards, Martin

Fourth Committee Member

Qian, Xianghong

Keywords

Membrane Technologies; Water Contamination; Membrane Modification

Abstract

Membrane technologies are attractive as they are linearly scalable and often require lower operating costs compared to other technologies. One area where they are particularly effective is the treatment of water contaminated with toxic substances. The simplicity of this removal mechanism provides reliable performance capable of meeting stringent removal requirements. However, membrane fouling is a major challenge that often limits their commercial viability. This research sought to investigate novel approaches to pretreatment and membrane modification to overcome fouling and high operating pressures. In addition, membrane separation processes can often be developed into simple yet educational experiments that are ideal for the creation of accessible research experiences. Research experiences are typically not accessible to students outside of four-year universities because they fail to effectively communicate their saliency to the student’s interests and career goals. The work in this dissertation aimed to demonstrate how leveraging ongoing research in a novel manner focused on mentoring is an effective strategy to give students experiences that increase the accessibility of research. The membrane research in this dissertation was an ideal case study for this approach since it is readily interdisciplinary and the outcomes of these projects directly impact the students who would typically not pursue careers in STEM fields. The first chapter of this dissertation reports reducing fouling during the filtration of algal toxins from lake water using electrocoagulation as a pretreatment, which had not previously been studied for nanofiltration. Electrocoagulation pretreatment conditions were studied for their impact on fouling resistance. It was found that aluminum electrodes at pH 7 resulted in larger flocs that were capable of removing 92±8.7% of organic carbon responsible for membrane fouling. This led to approximately three times less fouling, reducing the permeate flux decline from 29% with standard pretreatment to 9%. The next chapter explored a grafting from process using photo-initiated radical polymerization to introduce fixed charges to the surface of microfiltration membranes. The effect of grafting temperature and time on permeability and binding capacity were studied to determine that four minutes of exposure time at 35 °C led to strong binding performance while maintaining the ability to operate at low pressure. Filtration experiments demonstrated a dynamic binding capacity of 64.5±0.6 mg Cu2+/g of grafted weight and the treatment volume before breakthrough was increased by stacking membranes in series. The final chapter discusses the program through which this work and other relevant work with separations technologies was used to create a multi-tiered-mentoring-community based program for early-career researchers. Multiple concurrent programs for university students, community college students, and high school students were built to incorporate state-of-the-art separations research. Many of these students were from non-traditional and underrepresented backgrounds who don’t typically pursue research opportunities in STEM fields. Student feedback described how this design increased their self-efficacy as a researcher, research skills, and career awareness. Many students went on to present their research at conferences and pursue further research opportunities. These results demonstrate the efficacy of new approaches to traditional problems in the fields of membrane science and research education.

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