Spraying Model PAHs on a Charged TiO_2 Surface for High-Efficiency Degradation

摘要

The degradation of four model PAH compounds was studied by spraying from a micrometer-sized, grounded nozzle a solution of the PAH in a 1:1 solvent of toluene and isopropanol with a trace of water onto wetted TiO2 anatase nanoparticles, which were immobilized on an etched stainless-steel support charged at +2 kV. Rubrene was chosen because of its established degradation pathways, and 1-methylpyrene, 2-methylnapththalene, and bis(pyren-1-yl)ethane were chosen because of their molecular structure, containing aromatic islands with short aliphatic groups, representative of a thermally and catalytically processed heavy feed stream. The fractional reaction yield was measured using different support materials and by applying different external voltages to the metal substrate. The optimized method yielding 75% degradation was applied to the other three PAHs, resulting in higher-mass degradation products, apparently formed via radical polymerization.