| The goal of this work was to investigate the use of nanocrystalline calcium oxides as a means of destructively adsorbing various chemical species that are often identified as environmental pollutants. The chemicals that have been investigated can be grouped into categories such as chlorinated and fluorinated hydrocarbons, nitrogen oxides, sulfur compounds, and carbon oxides. The nanocrystalline calcium oxide has been shown to be a rather extraordinary destructive adsorbent for some species while proving to be rather inert to others.; The destructive adsorption reactions were carried out at elevated temperatures, typically in the range of 300–500°C. Often the products of the reactions were simple carbon oxides and calcium salts as was the case with chlorinated hydrocarbons, or just simply calcium salts when the calcium oxide sequestered sulfur or nitrogen oxides. In almost all cases it was found that AP-CaO was a better destructive adsorbent than CP-CaO and that coatings of small amounts of iron oxide enhanced the reactivity even more.; Low temperature/low pressure infrared spectroscopy was utilized to investigate the chemical and physical adsorption of some of the chemical species investigated in the gas chromatography destructive adsorbent experiments. This work allows for the identification of adsorbed surface species and, in some cases, the first steps in elucidating a mechanism for reaction with the calcium oxide nanoparticle.; In another set of experiments, EXAFS spectroscopy was used to investigate the nature of the iron oxide at the surface of the nanocrystals and the local disorder of the calcium oxide substrate. These experiments reveal that an intermediate iron species may be mobile over the surface of the substrate and act to seek out unreactive sites on the calcium oxide nanocrystal. |
