| This thesis represents work on the characterization of the surface properties of zinc oxide. High temperature drying, which is required to remove chemisorbed water from the zinc oxide surface, of a very small particle size zinc oxide powder resulted in a substantial decrease in the surface area. The surface areas of ZnO samples dried at 500{dollar}spcirc{dollar}C decreased continually as the drying time was increased. The ZnO powder employed was nonporous. No change in crystal structure occurred as a result of drying at 500{dollar}spcirc{dollar}C. The surface area decrease was due to a shift in the particle size distribution to a larger mean size. It was verified that ZnO exhibited significant sublimation at 500{dollar}spcirc{dollar}C. It was concluded that the increase in particle size was due to a sublimation-condensation process that obeyed the Kelvin equation.; Water, heptane, 1,4-dioxane and methanol vapor adsorption isotherms were determined for the ZnO. An FTIR spectrometer with a long path gas cell (IR pathlength of 3.0 m) was employed for the vapor adsorption measurements of the organic compounds. All of the isotherms exhibited Type II behavior. The surface areas obtained for the ZnO from BET analyses of the four vapor adsorption isotherms were nearly the same as the area obtained from the nitrogen vapor adsorption isotherm. The amount adsorbed by the ZnO at {dollar}P/Psb0{dollar} equal to 0.1, in terms of number of moles, was observed to decrease in the order: water {dollar}>{dollar}methanol {dollar}>{dollar}1,4-dioxane {dollar}>{dollar}heptane. It was found that water vapor rapidly displaced all of the adsorbed organic compounds from the ZnO surface. The amount of displacement by water increased as the amount of water added was increased, and as the amount of each test liquid used was increased. The extent of the heptane displacement by water, in terms of percentage of the area freed from heptane to the total surface area of the ZnO sample, was greater than that of 1,4-dioxane, which was greater than that of methanol. These results above are consistent with the expected strengths of interaction. |
