Many nonferrous industries such as mining and surface treatment plants produce co-products that are high in heavy metals and therefore toxic to the environment. A less obvious producer of heavy metal containing co-products is the whisky industry. Current methods of copper removal from such co-products include electrolysis and membrane filtration which are impractical and costly. When copper is found as a salt, current methods of removal include settlement, filtration and precipitation. Alternatives such as biological copper ion removal from effluents has also been shown to be effective. This study aimed to develop a biological method for the synthesis of stable copper nanoparticles. Morganella psychrotolerans was used to reduce Cu2+ to insoluble Cu0 nanoparticles. The nanoparticles were purified and characterised using X-Ray Photoelectron Spectroscopy (XPS) and High-Resolution Transmission Electron Microscopy (HR-TEM). Whisky distillery co-products were tested as a growth medium for M. psychrotolerans with concomitant copper nanoparticle synthesis. The copper nanoparticles were also studied for their application in electronics in order to make conductive circuits. Genomics studies combined with proteomics, helped develop possible models for copper nanoparticle synthesis by M. psychrotolerans, as well as identify proteins and genes not previously thought to be related to this pathway. The genome sequence of M. psychrotolerans obtained in this work allowed for a far more detailed study on the mechanism of copper nanoparticle synthesis than previously possible. This thesis also focused on understanding this mechanism better through proteomics and qRT-PCR. In order to study the identified copper ion reduction pathway in the future, a genetic modification toolkit was developed for M. psychrotolerans.

Este trabalho descreve, sob um ponto de vista atômico, a investigação das nanopartículas magnéticas (NPMs) de magnetita (Fe3O4) e ferritas do tipo TMFe2O4 (TM = Co, Ni), que são uma classe de materiais estruturados que atualmente tem um grande interesse devido à grande variedade de suas possíveis aplicações tecnológicas e biomédicas, pela Espectroscopia de Correlação Angular γ-γ Perturbada (CAP). Para a produção das NPMs foram utilizadas duas rotas químicas: o método de co-precipitação e o método de decomposição térmica. A co-precipitação apresenta as vantagens de ter temperaturas moderadas e custos relativamente baixos, porém não se consegue ter um controle da distribuição de tamanho das partículas. Por outro lado, a decomposição térmica possibilita uma amostra monodispersa com controle de tamanho e forma, mas este método necessita de reagentes tóxicos, caros e alta temperatura de reação. Para caracterização das amostras foi usada a técnica de Difração de Raio X (DRX) e a morfologia das NPs foi estudada por meio da Microscopia Eletrônica de Transmissão (MET). A partir desta técnica foi possível avaliar a distribuição do tamanho dos grãos, pois algumas características como, elevado valor de magnetização, alta anisotropia e um alto valor de coercividade são propriedades que dependem das nanoestruturas. As propriedades magnéticas foram estudadas localmente a partir da Correlação Angular Perturbada (CAP) que utiliza como sondas núcleos atômicos das medidas, como os núcleos de prova 111In (111Cd), 140La (140Ce) e 181Hf(181Ta). Estas propriedades foram complementadas por medidas de Magnetização. / This work describes, from an atomic point of view, the investigation of magnetic nanoparticles (MNPs) of magnetite (Fe3O4) and ferrites of the type TMFe2O4 (TM = Co, Ni), which are a class of structured materials that currently have a great interest due to the great variety of its possible technological and biomedical applications by Perturbed γ-γ Angular Correlation Spectroscopy (PAC). Two chemical routes were used to produce MNPs: the co-precipitation method and the thermal decomposition method. Co-precipitation has the advantages of having moderate temperatures and relatively low costs, but particle size distribution control is not achieved. On the other hand, the thermal decomposition allows a monodisperse sample with size and shape control, but this method requires toxic reagents, expensive and high reaction temperature. The X-Ray Diffraction (XRD) technique was used to characterize the samples and the morphology of the NPs was studied by Electron Transmission Electron Microscopy (TEM). From this technique it was possible to evaluate grain size distribution, because some characteristics such as high magnetization value, high anisotropy and a high coercivity value are properties that depend on the nanostructures. The magnetic properties were studied locally from the Perturbed Angular Correlation (CAP), which uses as probe nuclei of the measurements, such as 111In (111Cd), 140La (140Ce) and 181Hf (181Ta). These properties were complemented by Magnetization measurements.

Este trabalho descreve, sob um ponto de vista atômico, a investigação das nanopartículas magnéticas (NPMs) de magnetita (Fe3O4) e ferritas do tipo TMFe2O4 (TM = Co, Ni), que são uma classe de materiais estruturados que atualmente tem um grande interesse devido à grande variedade de suas possíveis aplicações tecnológicas e biomédicas, pela Espectroscopia de Correlação Angular γ-γ Perturbada (CAP). Para a produção das NPMs foram utilizadas duas rotas químicas: o método de co-precipitação e o método de decomposição térmica. A co-precipitação apresenta as vantagens de ter temperaturas moderadas e custos relativamente baixos, porém não se consegue ter um controle da distribuição de tamanho das partículas. Por outro lado, a decomposição térmica possibilita uma amostra monodispersa com controle de tamanho e forma, mas este método necessita de reagentes tóxicos, caros e alta temperatura de reação. Para caracterização das amostras foi usada a técnica de Difração de Raio X (DRX) e a morfologia das NPs foi estudada por meio da Microscopia Eletrônica de Transmissão (MET). A partir desta técnica foi possível avaliar a distribuição do tamanho dos grãos, pois algumas características como, elevado valor de magnetização, alta anisotropia e um alto valor de coercividade são propriedades que dependem das nanoestruturas. As propriedades magnéticas foram estudadas localmente a partir da Correlação Angular Perturbada (CAP) que utiliza como sondas núcleos atômicos das medidas, como os núcleos de prova 111In (111Cd), 140La (140Ce) e 181Hf(181Ta). Estas propriedades foram complementadas por medidas de Magnetização. / This work describes, from an atomic point of view, the investigation of magnetic nanoparticles (MNPs) of magnetite (Fe3O4) and ferrites of the type TMFe2O4 (TM = Co, Ni), which are a class of structured materials that currently have a great interest due to the great variety of its possible technological and biomedical applications by Perturbed γ-γ Angular Correlation Spectroscopy (PAC). Two chemical routes were used to produce MNPs: the co-precipitation method and the thermal decomposition method. Co-precipitation has the advantages of having moderate temperatures and relatively low costs, but particle size distribution control is not achieved. On the other hand, the thermal decomposition allows a monodisperse sample with size and shape control, but this method requires toxic reagents, expensive and high reaction temperature. The X-Ray Diffraction (XRD) technique was used to characterize the samples and the morphology of the NPs was studied by Electron Transmission Electron Microscopy (TEM). From this technique it was possible to evaluate grain size distribution, because some characteristics such as high magnetization value, high anisotropy and a high coercivity value are properties that depend on the nanostructures. The magnetic properties were studied locally from the Perturbed Angular Correlation (CAP), which uses as probe nuclei of the measurements, such as 111In (111Cd), 140La (140Ce) and 181Hf (181Ta). These properties were complemented by Magnetization measurements.

No description available.

Core-shell nanohybrids have wide applications in pollutant degradation. In this study, core-shell nanohybrid was formed through heteroaggregation between neutral nanoparticles (i.e., hematite nanoparticles or HemNPs) and charged nanoparticles (i.e., carboxylated polystyrene nanoparticles or PSNPs). In the dispersant solution of 1 mM NaCl at pH 6.3, HemNPs were neutral and underwent favorable homoaggregation, whereas PSNPs were negatively charged and underwent no homoaggregation. When the two types of particles were mixed, homoaggregation of HemNPs and heteroaggregation between HemNPs and PSNPs took place simultaneously, forming HemNPs-PSNPs heteroaggregates. The transmission electron microscopy images of heteroaggregates show that HemNPs and PSNPs formed core-shell structure in which HemNPs were the cores and PSNPs were the shells. The size of the core-shell nanohybrids can be controlled by varying the concentration ratio of HemNPs to PSNPs. The increase of the size of charged nanoparticles resulted in larger nanohybrids. This new method has lower energy footprint than existing ones. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Silica is one of the most abundant elements on the planet, has flexible bonding properties and generally excellent stability. Because of these properties, silica has been a vital component in technologies ranging from ancient glassware to modern supercomputers. Silica is able to form a wide range of materials both alone and as a component of larger material frameworks. Porous silica based nanomaterials are rapidly growing in importance because of their many applications in a wide variety of fields. This thesis focuses on the synthesis of silica based porous nanomaterials: nanocrystalline zeolites, mesoporous silica nanoparticles, and iron oxide core/shell nanocomposites. The synthetic conditions of these materials were varied in order to maximize efficiency, minimize environmental impact, and produce high quality material with far reaching potential applications. The materials were characterized by physicochemical techniques including Transmission Electron Microscopy, Dynamic Light Scattering, Powder X-Ray Diffraction, Solid State NMR, and Nitrogen Adsorption Isotherms. The materials were evaluated and conditions were controlled to produce high yields of quality nanomaterials and hypothesize methods for further synthetic control. The products will be used in studies involving nanoparticle toxicity, environmental remediation, and drug delivery.

The goal of this project was to study the behavior of copper oxide nanoparticles in soil environments. Copper oxide nanoparticles have antimicrobial properties and may also be used in agricultural settings to provide a source of copper for plant health, but accidental or misapplication of these nanoparticles to soil may be damaging to the plant and its associated bacteria. Dissolved soil organic matter that is present in soil pore waters dissolved nanoparticles, but did not dissolve the expected amounts from a geochemical model because the geochemical model did not take into account surface chemistry or coating of the nanoparticles by dissolved organic matter. Wheat grown in soil pore water increased the solubility of the nanoparticles. The nanoparticles and dissolved copper were harmful to wheat, but dissolved soil organic matter remediated a portion of the damage. These studies were conducted with Utah soils and wheat, a highly valuable Utah crop. These results suggest that contamination of soils by copper oxide nanoparticles will be partially mitigated by the organic matter content of the soil. Producers of fertilizers and fungicides may use various forms of organic matter to deliver products that are targeted to specific plants or pathogens and avoid damage to non-target organisms.

No description available.

Delivery of complex molecules such as peptides, proteins, oligonucleotides and plasmids is an intensively studied subject, which has attracted considerable medical and pharmaceutical interest. Encapsulation of these molecules with biodegradable polymers represents one way of overcoming various problems associated with the conventional delivery of macromolecules, for example instability and short biological half-life. The use of carriers made of hydrophilic polysaccharides such as chitosan, has been pursued as a promising alternative for improving the transport of biologically active macromolecules across biological surfaces. The development of nanoparticles as a delivery system also has major advantages of achieving possible drug protection, controlled release and drug targeting by either a passive or an active means. The aim of this study was to develop a simple and effective method to formulate biodegradable nanoparticles for the delivery of a model protein-bovine serum albumin (BSA) and an angiogenesis inhibitor, arginine-rich hexapeptide (ARE peptide). Major factors which determine nanoparticle formation and loading of the protein and the peptide as well as the underlying mechanisms controlling their incorporation and release characteristics were investigated. The preparation technique, based on the complex coacervation process, is extremely mild and involves the mixture of two aqueous solutions (chitosan and dextran sulfate) at room temperature. The formation of nanoparticles is dependent on the concentrations of chitosan (CS) and dextran sulfate (DS); particles with size, of 257 to 494nm can be obtained with 0.1%w/v solutions of CS and DS. Zeta potential of nanoparicles can be modulated conveniently from -34.3mV to +52.7mV by varying the composition of the two ionic polymers. / Both bovine BSA and the ARH peptide were successfully incorporated into CS-based nanoparticles, mainly via an electrostatic interaction, with entrapment efficiency up to 100% and 75.9% for the protein and peptide respectively. Incorporation of both the protein and peptide into nanoparticles resulted in an increase in size suggesting their close association with the nanoparticle matrix material. The difference in sign and magnitude of zeta potential of empty and macromolecules-loaded nanoparticles supports the hypothesis that protein and peptide association with nanoparticles can be modulated by their ionic interaction with the oppositely charged ionic polymer (DS) in the nanoparticles. The release of BSA from the nanoparticles was very slow in water compared to that in l0mM phosphate buffer pH 7.4; whereas, ARH peptide showed extremely low level of release in water at the low ratio of DS but at the high ratio of DS, its release was in biphasic fashion, with an initial burst effect followed by an almost constant but very slow release up to 7 days in both water and 1 OmM phosphate buffer (pH 7.4). It was found that, unlike ARH peptide, the percentage of BSA released was relatively slower for the nanoparticles with a high ratio of DS. It is speculated that this difference in the release behaviour of BSA and ARH peptide, could be due to the effect of molecular size of the compounds and their interaction with the polymer matrix of the nanoparticle. The results of this study suggest that these novel CS/DS nanoparticulate system, prepared by a very mild ionic crosslinking technique, have potential to be a suitable carrier for the entrapment and controlled release of peptides and proteins.

This thesis focuses on the shape-controlled metal nanoparticles for functional applications, covering the synthesis, characterization and optical properties. Three parts are mainly involved in this work, including, gold worm-like nanoparticles, silver nanoplates, and silver induced selenium nanowires. The first part focuses on a facile synthesis method for shape control of gold nanoparticles by treating an aqueous solution of chloroauric acid with sodium citrate and poly(vinyl pyrrolidone) (PVP), in which those worm-like nanoparticles were investigated by various advanced experimental characterizations combining density function theory (DFT) calculation. These nanoparticles can be used for optical sensing detection of ions in aqueous system. The second part involves the synthesis, growth, and optical properties of silver nanoplates (triangles and circular discs). Such nanoplates could be synthesized by a self-seeding co-reduction method at ambient conditions. In particular, molecular dynamics simulation is used to quantify the interaction energies between surfactant molecules and different facets of silver crystal. Such molecular information, together with measurements using x-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and ultraviolet??visible (UV??vis) spectroscopy, has proven to be useful for understanding the growth mechanisms of silver nanoplates. The third part focuses on the template of silver nanoparticles for generating trigonal selenium (t-Se) nanowires. This technique exhibits some advantages in fabricating t-Se nanostructures, including no need to use stabilizers and sonichemical process and all operations being proceeded in aqueous media and at room temperature. Particularly it can successfully achieve the transformation from amorphous α-Se to crystalline t-Se in aqueous solution and this method would be useful for generating one-dimensional nanostructures with similar lattice parameter(s). It is considered that the technique for the shape-controlled metal nanoparticles can at least partially, be extended to other nanomaterials for functional applications.