Photochemical transformation of pyrene vapor deposited on eleven subfractions of a high‐carbon coal stack ash

Abstract

A high‐carbon coal stack ash has been separated by particle size and then by composition, into strongly magnetic, weakly magnetic, “nonmagnetic” mineral, heavy carbon and light carbon fractions. Eleven of these fractions have been characterized by bulk iron and carbon analyses and BET surface area determinations. The photochemical transformation of pyrene, deposited from the vapor phase onto these eleven ash fractions, has been studied. Appreciable phototransformation of adsorbed pyrene was observed for only three fractions; in those fractions, the bulk percentage of carbon (0.4–0.7%) and the specific surface area (0.50–0.68 m2/g) were both very low. For all fractions having bulk carbon percentages ≥ 4% and specific surface areas ≥ 2.85 m2/g, no detectable phototransformation of adsorbed pyrene was observed. There was no discernible correlation of photochemical reactivity of adsorbed pyrene with the iron content of the ash fractions. In general, the specific surface area of the fractions increased with increased carbon content; two different forms of carbon having different surface areas were observed.

Sorption and chemical transformation of PAHs on coal fly ash

“…A second ash fractionation proved considerably more successful. Considerable work has been carried out in this laboratory using a relatively high-carbon coal stack ash obtained from a malfunctioning steam plant in Florida (the "so-called "Kaneb" ash described previously [1,2]). Previous fractionations of this ash employed a density separation that used organic solvents; it was desired to carry through a separation in which contact of the ash with ali foreign materials was avoided (i.e., in which ali denslty-based particle separations involved elutriation only).…”

“…Since this assumption is not generally valid for coal fly ash [1,2], this simple technique for determining fractal dimensions is inapplicable to fly ash.…”

Atmospheric Behavior of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans and the Effect of Combustion Temperature

“…Native PCDD/Fs found on fly ash ranging in color from black to yellow did not photodegrade in laboratory studies (11). Studies of the photodegradation of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs adsorbed onto fly ash indicated that the darker the color of the fly ash, which was controlled by the carbon content, the greater the stabilizing effect on the adsorbed substances (17)(18)(19)(20)(21). Studies of the photodegradation of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs adsorbed onto fly ash indicated that the darker the color of the fly ash, which was controlled by the carbon content, the greater the stabilizing effect on the adsorbed substances (17)(18)(19)(20)(21).…”

Sorption and chemical transformation of PAHs on coal fly ash. Technical progress report No. 5, [November 1, 1992--January 31, 1993]

“…(i) The photochemical transformation of l-nitropyrene sorbed on various subfractions of "Kaneb" fly ash (prepared according to previously published techniques [1,2]) has been studied.…”