An experimental setup was built to use a TSI Scanning Mobility Particle Sizer (SMPS, model 3936) instrument to investigate the time resolved evolution of particles from the ozonolysis of a-pinene and related compounds. This apparatus was characterised using the reaction of a-pinene with ozone. The time profile of aerosol mass was used to determine a value for the rate constant of k, = 9.48 X 10.17 cm3 molecule-1 S-1, which is within 5% of a recently recommended literature value. The dependence of the physical properties of the aerosol on some starting conditions was examined, and the dependence of aerosol yield on mass load examined. The particularly large effect of the nature of the OH radical scavenger on the particle number concentration was noted.

The production of synthesis gas through dry reforming of methane has been investigated. Different technologies: thermal and induction heating and plasma activation, have been compared with respect to energy usage in the context of renewable energy capture.

Adsorption takes place whenever a solid surface is exposed to a gas or liquid, and is characterized by an increase in fluid density near the interface. Adsorbents have attracted attention in the ongoing effort to engineer materials that can effectively remove various pollutants from wastewaters. Carbon adsorbents are a logical choice as an adsorption material due to their low costs and large surface areas. The adsorption of chromium(VI), aluminium and copper onto commercial activated carbon was studied in a series of batch, kinetic and column experiments. The adsorption of the three ions was studied separately followed by studies of the competition between the ions in binary and ternary systems. The experimental data was utilized to set up models for sorption of chromium(VI), aluminium and copper onto commercial activated carbon. This was done to enhance the understanding of the governing processes controlling adsorption as well as to develop a tool to predict the fate of chromium(VI), aluminium and copper in a calcareous environment. To avoid the precipitation of the ions, the binary and ternary experiments were conducted without pH adjustment. This thesis has used multiple analytical techniques in order to enhance the knowledge of Cr(VI), AI(III) and Cu(II) binding to the activated carbon adsorbent and thus attempts to interpret.the potential binding mechanisms. The changes in adsorbent functional groups and surface topography after chromium binding were monitored using FT-IR and SEM/EDX analysis. The experimental studies include: i) evaluation and characterisation of the commercial activated carbon; ii) evaluation and optimisation of commercial activated carbon removal capability, kinetics and mechanisms toward Cr(VI), AI (III) and Cu(II) via the batch, kinetic and continuous adsorption systems. From the pH studies, it was observed that pH 2 produced the highest removal of chromium. The ternary solution at pH 2 showed less removal of chromium than the other solutions suggesting that the combined -effect of Cu and AI metals was more considerable. Two common adsorption isotherms, i.e. the Freundlich and Langmuir models As well as Redlich-Peterson model were employed to describe the adsorptive characteristics of the activated carbon. The adsorptive kinetic studies revealed that the adsorption of activated carbon followed the pseudo-second order kinetic models, indicating the adsorption mechanism was dependent on the adsorbate and adsorbent interaction.

No description available.

Materials with inherent oxygen excess are of great interest for high-temperature electrochemical applications, such as solid oxide fuel cells (SOFCs) and oxygen permeation membranes due to their rapid ion conductivity. Cerium niobate has received a lot of attention recently due to its rapid oxide ion conductivity in the intermediate temperature range (500-650 °C). Cerium niobate has several interesting characteristics, such as the range of excess oxygen structures that stabilise in the monoclinic crystal system and the phase transition from monoclinic to tetragonal crystal structures associated with a change in ionic conductivity. During this work the first single crystal study of CeNbO4 has been performed and as a result of the higher quality of data available with single crystal diffraction a correction to the space group reported in literature has been suggested. Furthermore, single crystals have been thermally treated in order to synthesis the excess oxygen modulated structures. CeNbO4.25 has been successfully synthesised and the crystal structure has been solved with a large superstructure of 75 independent atomic positions. Structural analysis of the complex anion framework suggests a potential anisotropic oxygen ion conduction pathway through the material. XANES work has been reported on the cerium niobate structures looking at in-situ measurements as a function of temperature. This work has allowed identification of a new phase with an approximately stoichiometry of CeNbO4.16. Bond valence calculations have been performed to study the effect of additional oxygen content on overall crystal strain. Finally, in an effort to synthesise a novel electrolyte using cerium niobate as a model structure, an analogous material, LaNb0.84W0.16O4.08 has been synthesised in an attempt to reproduce the ionic conductivity observed whilst eliminating the electronic component associated with the mixed valence of the cerium cation. LaNb0.84W0.16O4.08 has been successfully synthesised and some initial structural and electrochemical characterisation have been performed with very promising results. Total conductivity has shown the material to outperform YSZ at 1000 °C and in addition the material has a large ionic domain with negligible electronic conductivity at 10-22 atm p(O2). Initial diffusivity measurements and fuel cell testing results correlate well with electrochemical measurements via AC impedance. Furthermore, the thermal expansion coefficient of the material is suitable with typical electrode materials meaning this is a promising new material for high oxide ion transport.

A one-component emulsion templating strategy for the preparation of inorganic-organic encapsulated droplets and hollow capsules has been developed. The process exploits, and relies on, both branched addition co-polymer architectures and compositions, which provide simultaneous properties of emulsion droplet steric-stabilisation and cross-linking function. It was demonstrated that high yielding encapsulation of different hydrophobic actives was successful whilst retaining the structural integrity of the capsule compartments. Responsive capsule surfaces and shell/membrane properties with pre-determined complex functionalities were demonstrated. The incorporation of chemical functionality within the reactive branched addition co-polymer allowed higher order responsive structures to be formed. These materials have been shown to be highly useful in the preparation of large associated aggregates which can be loaded with numerous payloads. The encapsulation of both hydrophobic dyes and an oil-soluble polymer was illustrated. Protocell constructs with pH-mediated, electrostatically gated permeability were prepared by covalently grafting a multi-responsive functional terpolymer to the outer surface of a cross-linked membrane of silica nanoparticle-based colloidosomes. Terpolymer grafted membrane functionality-mediated uptake and release of small molecules from the colloidosomes was demonstrated.

No description available.

No description available.

No description available.

No description available.