Date of Award
12-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
Committee Chair/Advisor
Dr. Daniel C Whitehead
Committee Member
Dr. Rhett Smith
Committee Member
Dr. Brian Dominy
Committee Member
Dr. Byoungmoo Kim
Abstract
Cellulose nanocrystals (CNCs) coupled with polymers featuring a high density of amine functional groups, such as polyethylenimine (PEI), exhibit significant metal-capturing capabilities. Rendered animal fat has applications in a vast number of industries, with the potential to be used as a feedstock for the biodiesel/renewable diesel industries. Nevertheless, rendered fat samples occasionally contain concentrations of metals/inorganic contaminants above the suitable threshold for use in this application. Thus, a cost-effective solution to remove light metal/inorganic contaminants from rendered fat samples is desirable.
To address this problem, a cellulose nanocrystal coupled with polyethylenimine, i.e., CNC-f-PEI, was developed by previous members of the Whitehead lab to aid in the removal of metals/inorganics from rendered fat. This method was effective in removing approximately 95% of metals from the rendered fat; however, it proved too costly to use at an industrial scale due to the high costs of the required reagents and purification steps for the first-generation synthesis of the material. This issue was addressed by replacing the costly reagents with a cheaper coupling agent to graft the polyamine onto the cellulose nanocrystals. Further, we decided to forgo the costly dialysis purification step. The second generation material worked well for the removal of metal contaminants from rendered fat samples, with the exception of sodium cations, which contaminated the CNC-f-PEI material, owing to the elimination of the dialysis purification.
The work of this dissertation has resolved this issue by developing a method to remove sodium and sulfur contamination from the raw CNCs prior to PEI grafting using CDI. This work allows for significantly more cost-effective second generation synthesis of CNC-f-PEI, which is more amenable to scale-up. Importantly, CNC-f-PEI material prepared using this technique retains its strong performance in the removal of metal contaminants from rendered animal fat, achieving approximately 96% removal of target contaminants.
Recommended Citation
Rehman, Sheikh Abdur, "Process Optimization and Cost Reduction for Cellulose Nanocrystals for Metal Removal From Rendered Fat" (2025). All Theses. 4636.
https://open.clemson.edu/all_theses/4636