Carbonaceous particle hydration III

Previous soot hydration studies have been extended to compare the water upt ake properties of soots from selected fuels (JP-8 Jet fuel, kerosene, diese l, and metal containing and S-containing synthetics) prepared under varying conditions with corresponding n-hexane model soots. Adsorption and desorpt ion isotherms have yielded such adsorption parameters as the surface covera ges at the limit of chemisorption and at 83% relative humidity (RH). These values increase with soot surface oxidation over the range 35-85% RH, while hydration levels at lower RH down to 22% are a function of fuel compositio n and combustion conditions, thus determining the extent of water uptake at higher RH. Both S- and metal-containing soots exhibit higher levels of hyd ration than those of the base fuel soots, a result with its origin in avail ability of sulfate and metal centers at the surface.