Engineering of Cellulose for Regulating Interfacial Ionic Interactions in Health and Environmental Applications
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- Author:
- Yeh, Shang Lin
- Graduate Program:
- Chemical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- January 09, 2024
- Committee Members:
- Robert Rioux, Professor in Charge/Director of Graduate Studies
Andrew Read, Outside Unit & Field Member
Amir Sheikhi, Chair & Dissertation Advisor
Stephanie Velegol, Major Field Member
Andrew Zydney, Major Field Member - Keywords:
- Cellulose
Rare earth elements
Scales
Antimicrobial resistance
Ionic interactions - Abstract:
- Sustainability is the key to addressing contemporary challenges within both environmental and healthcare sectors. In environmental aspects, water treatment such as scale mitigation in unit operations or the recovery of valuable elements such as rare earth elements (REE), demand eco-friendly strategies to minimize environmental footprints. In the realm of healthcare, the removal of unwanted molecules from body fluids, such as sequestering off-target antibiotics to overcome antimicrobial resistance (AMR) aligns with the United Nations Sustainable Development Goal 3, i.e., good health and well-being. Cellulose, the most abundant biopolymer on earth, is chemically modified with various charged groups or ligands for many interface-dependent applications. The current bottleneck in cellulose-based materials arises from the limited functional group density, primarily caused by the inaccessibility of inner crystalline regions of cellulose fibrils. To enhance the ion interactions of cellulose-based materials, cellulose is preferentially oxidized at disordered regions to produce hairy nanocelluloses with protruding polymer chains (“hairs”), enabling a functional group density (> 5 mmol g-1) several times higher than the conventional nanocelluloses. The first part of dissertation focuses on designing a novel one-step mussel-inspired nanocellulose coating (MINC) using bifunctional hairy nanocelluloses (BHCNC), bearing dialdehyde and dicarboxylate groups, for neodymium (Nd) recovery. REE such as Nd, play a crucial role in the advancement of magnetic medical equipment, clean energy, and electronic devices. However, the global supply of this element is still limited, and current practices, such as solvent extraction, have negative environmental impacts. The MINC approach uses dialdehyde groups, enabling dopamine-mediated orthogonal conjugation of BHCNC to substrates. Additionally, the high content of dicarboxylate groups yields high-capacity, selective Nd removal against ferric, calcium, and sodium ions. The MINC-treated substrates provide rapid selective removal and recovery of Nd ions with a capacity of 140 mg g-1. We envision that the MINC-treated substrates, such as microparticles, can cyclically recover Nd in the electronics industry. The second part of dissertation focuses on developing an amphiphilic hairy nanocellulose (AmHCNC) for mitigating calcium carbonate (CaCO3) scales during crude oil transportation. The ionic interactions between calcium ions (Ca2+) and carbonate ions (CO32-) are important in regulating the formation or inhibition of CaCO3 scales. During crude oil transportation, CaCO3 scales are produced as a result of ionic incompatibility between the injected water and the formation water inside the reservoir, leading to severe fluctuations in ion concentrations and supersaturation. Scaling results in significant operational damage, safety concerns, and economic losses in pipelines. Despite the extensive investigations on CaCO3 precipitation in aqueous media, CaCO3 scale formation in multiphase systems is not fully understood. Here, we first engineer microfluidic-enabled stable W/O emulsions via multifactorial optimizations to uncover the influence of emulsion properties on the CaCO3 scaling kinetics. We hypothesize that ionic interactions between cationic surfactant and CaCO3 retard the CaCO3 scaling kinetics and destabilize the W/O emulsion. Then, AmHCNC is developed by anchoring hydrophobic alkyl groups on bifunctional cellulose fibrils via a Schiff-base reaction without compromising the carboxylate sites to impair CaCO3 scaling. Additionally, the amphiphilic structure of AmHCNC stabilizes the W/O Pickering emulsions. We envision that the AmHCNC provides a green solution for conventional anti-scaling agents and surfactants such as Span 80 in petroleum industry. The third part of dissertation focuses on developing a super-capacity oral adjuvant therapy to combat the AMR evolution. The ionic interactions between charged antibiotics and the oral adjuvant may play an important role in removing or eliminating the antibiotics. Instead of developing new antibiotics, we hypothesize that breaking the connection between intravenous (IV) antibiotic use and off-target antibiotic in gastrointestinal (GI) tract may protect current antibiotics. Ion exchange biomaterials (IXB) are explored as oral adjuvants to reduce the vancomycin (VAN)- or daptomycin (DAP)- resistant populations of Enterococcus faecium in the GI tract. We first investigate the IXB-mediated antibiotics removal from several aqueous media with controlled pH and electrolyte concentrations as well as from simulated intestinal fluid to uncover the molecular and colloidal mechanisms of IXB-antibiotic interactions in the GI tract. Then, we rationally design a new biomaterial via integrating anionic hairy cellulose nanocrystals (AHCNC) with Food and Drug Administration (FDA)-approved oral adjuvant (cholestyramine, CHA), referred to as AHCNC-CHA, to sequester off-target VAN from the GI tract. In mice treated with VAN, adjunctive AHCNC-CHA therapy reduced the fecal shedding of VREfm by 63%. We envision this strategy may protect IV antibiotics and address the global threat of AMR. In conclusion, regulating ionic interactions by engineered cellulose holds a great promise to address several societal challenges. Together, these examples show that the micro-/nanoengineering of cellulose combined with the fundamental studies of interfacial ionic interactions leverage promising bio-based colloidal platforms in the health-water-energy nexus.
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