Kinetics of saturated water vapor sorption on soot particles

In order to study the condensation activity of carbon-containing aerosols, the kinetics of sorption of saturated water vapors was investigated on model soot samples modified by the deposition of organic and inorganic substances corresponding to different classes of compounds contained in solid state products of natural fuel combustion. The values of limiting water sorption were determined and rate constants were calculated. It was established that the limiting sorption on graphitized thermal soot (GTS) modified by acids and salts (e.g., phenol, benzoic, phthalic, trimellitic, and sulfuric acids; sodium benzoate; and ammonium sulfate) per modifier molecule rose by two orders of magnitude, relative to the initial carbon matrix, and ranged from a parts per thousand 2 to 200 molecules. It was found that hydrophilic centers covalently bound to the surface of furnace black (FB) and its oxidized form are shielded to a considerable degree as a result of modification by hydrophobic substances (hexadecane, octacosane, anthracene, and stearic acid). We conclude that hexadecane modification of GTS containing hydrophilic centers not bound to its surface (sulfuric acid and ammonium sulfate molecules) have no effect on the sorption of saturated water vapors.