Document Type

Honors Thesis

Publication Date

Spring 5-8-2026

Abstract

Bacterial cellulose (BC) has emerged as a promising bio-based material for membrane filtration due to its high purity, interconnected nanofibrillar structure, and tunable physical properties. However, unmodified BC membranes function primarily as passive filtration materials, with performance largely governed by pore size and lacking the ability to effectively interact with dissolved contaminants. This study investigates the modification of BC membranes through a combination of mechanical pressing, chitosan functionalization, and citric acid crosslinking to enhance both structural control and functional performance. BC membranes were synthesized using a kombucha-based system and subsequently purified, mechanically compressed, and chemically modified. Results demonstrated that the modification process reduced average pore size from approximately 0.5 μm to less than 0.1 μm and improved structural uniformity, while maintaining viable permeability. Flux measurements exhibited pressure-dependent behavior, with an initial linear increase followed by a plateau of approximately 0.011 L / m²·hr at higher pressures (>20 psi or 1.38 bar), indicating the presence of internal resistance mechanisms such as membrane compaction. FTIR analysis confirmed the retention of the cellulose backbone but did not reveal distinct new peaks associated with chemical modification, likely due to spectral overlap and limited sensitivity. Overall, the findings indicate that BC membranes can be successfully engineered to achieve controlled structural and transport properties without compromising permeability. This work demonstrates the potential of BC as a tunable platform for membrane design and highlights its applicability for advanced water treatment systems, particularly in scenarios requiring lightweight, sustainable, and multifunctional materials.

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