engleski

Heterogeneous Polycyclic Aromatic Hydrocarbon Degradation with Ozone on Silica Gel Carrier

Heterogeneous degradation of five polycyclic aromatic hydrocarbons (PAHs), perylene (Pe), pyrene (Py), benzo(a)pyrene (BaP), benzo(a)anthracene (BaA) and fluoranthene (Flo) adsorbed on nonactivated (moisture-containing) silica gel with ozone in a fluidized bed reactor has been studied.The concentrations of ozone employed varied from 0, 050 to 0, 400 ppm.The results obtained show that, concerning their kinetics, there is a clear difference between reactions with less then and more than monolayer coverage of the particle surface with PAHs, those carrying a submonomolecular layer being faster and indicating the effect of the particle surface. In more highly covered samples, the observed degradation obeys two distinct first-order laws, the slow one changing into the faster at monomolecular coverage ; the relative reactivities are as follows: Pe>BaP>BaA>Py>>Flo, and BaP>Pe>BaA>Py>>Flo, respectively. According to the present results, heterogeneous degradation of PAHs by ozone on particle surfaces is one of important pathways for their removal from the atmosphere.

eterogeneous reactions ; PAH ; ozone ; silica gel carriar

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