Photochemical investigations of surface adsorbed polycyclic aromatic hydrocarbons

A magnet was utilized to collect five ferromagnetic (iron enriched) coal fly ash fractions from the bulk ashes. These ashes were then dissolved and analyzed by atomic absorption to determine their iron content.

Pyrene was deposited onto the surfaces of these ashes and two iron oxides. These samples were then illuminated with a light source similar in spectral distribution to sunlight. Adsorbed pyrene was then extracted from the substrates, and the decrease in the pyrene concentration of the substrate (ash) due to illumination was assumed to be the result of photochemical decomposition. The percentage of photodecomposition of pyrene on each substrate was calculated. The iron oxides and ferromagnetic fractions of coal fly ash showed a tendency to stabilize surface adsorbed pyrene to photodecomposition.

An aqueous chemical actinometer was developed from a mixture of p-nitroanisole and pyridine. This actinometer system was utilized to measure the power (and intensity) of polychromatic radiation from a xenon lamp (that was used to illuminate fly ash samples). Good precision (± 12 %) was observed for the power determinations utilizing this system.