In situ chemical oxidation using permanganate is an approach to organic contaminant site remediation. Manganese dioxide particles are products of permanganate reactions. These particles have the potential to deposit in the subsurface and impact the flow-regime in/around permanganate injection, including the well screen, filter pack, and the surrounding subsurface formation. Control of these particles can allow for improved oxidant injection and transport and contact between the oxidant and contaminants of concern. The goals of this research were to determine if MnO2 can be stabilized/controlled in an aqueous phase, and to determine the dependence of particle stabilization on groundwater characteristics. Bench-scale experiments were conducted to study the ability of four stabilization aids (sodium hexametaphosphate (HMP), Dowfax 8390, xanthan gum, and gum arabic) in maintaining particles suspended in solution under varied reaction conditions and time. Variations included particle and stabilization aid concentrations, ionic content, and pH. HMP demonstrated the most promising results, as compared to xanthan gum, gum arabic, and Dowfax 8390 based on results of spectrophotometric studies of particle behavior, particle filtration, and optical measurements of particle size and zeta potential. HMP inhibited particle settling, provided for greater particle stability, and resulted in particles of a smaller average size over the range of experimental conditions evaluated compared to results for systems that did not include HMP. Additionally, HMP did not react unfavorably with permanganate. These results indicate that the inclusion of HMP in a permanganate oxidation system improves conditions that may facilitate particle transport.

Solid lipid nanoparticles (SLNPs) and lipid-drug conjugates (LDCs) are two promising lipid nanoparticle (LNP) based drug delivery systems; this thesis explores new synthetic lipids that may circumvent the limitations of currently available components for LNPs with particular focus on the stability of LNP formulations. Neutral polyethylene glycol lipids (PEG-lipids) have been designed, synthesized, and characterized with ESI-MS, for stabilizing SLNPs containing dsDNA oligomer. 1st and 2nd generation PEG-lipids investigated the effects of serinol and iminodiacetic acid backbone structures, respectively, and aliphatic chain sequences within the lipid anchors on the stability of SLNPs. Assays were developed to analyze LNP stability in both PBS buffer and PBS buffer with 10 % serum at different incubation temperatures. The results indicate that the hydrocarbon branching sequence offer additional SLNP stability over straight chain isomers. LDC monomers were designed and synthesized to allow for the formulation of LDC nanocarriers for the thiopurine drugs. These hydrophobic LDC monomers were made by linking the polar thiopurine drug to a synthetic lipid. These synthetic lipids investigated branched and straight chain derivatives – the branched isomers once again demonstrated advantages in the stability of the LDCs. / Graduate

High-Gradient Magnetic Separation (HGMS) is a powerful separation process that has great potential for industrial wastewater treatment, particularly for the removal and recovery of paramagnetic colloidal particles. The chief advantages of HGMS are that the separation is reversible and potentially selective. However, these advantages are compromised if non-magnetic filtration mechanisms influence significantly the capture of particles. The objective of this study was to identify the chief mechanisms responsible for the removal of ferric oxide (Fe2O3) from water by an HGMS process. This objective was achieved by measuring the effects of applied magnetic induction, collector radius, and fluid velocity on the removal efficiency (RE) of a stainless-steel filter column. These factors were tested on the removal of bare Fe2O3 particles and particles treated with a surfactant (sodium dodecyl sulfate, SDS). The results were compared to the predictions of a trajectory model which simulates particle capture by a magnetic force. The experimental results show that non-magnetic force mechanisms are primarily responsible for the removal of bare Fe2O3 particles for the experimental conditions used in this work. For these particles, the three factors tested had no significant effect on the RE, and 90.1% of the particles were removed without a magnetic force. These results differed sharply from modeling predictions. However, the magnetic force mechanism is primarily responsible for the removal of surfactant-treated Fe2O3 particles. The three factors investigated had a marked effect on the RE, and only 10.8% of the particles were removed without a magnetic force. An increase in magnetic induction from 0.2 to 0.5 T increased the RE from 79.9 to 93.4 %; a decrease in wire radius from 49 to 15 Ym increased the RE from 60.2 to 93.4%, and a decrease in fluid velocity from 0.5 to 0.1 cm/s increased the RE from 69.5 to 95.3%. These results agreed closely with the model predictions.This study demonstrates that by reducing the effect of attractive non-magnetic forces on filtration, surfactant treatment of colloidal particles can potentially preserve and enhance these two key advantages, i.e., regeneration and selectivity of HGMS processes.