Reaction of Polycyclic Aromatic\nHydrocarbons Adsorbed on Silica in\nAqueous Chlorine

Abstract

The reaction of polycyclic aromatic hydrocarbons (PAHs)\npreviously adsorbed on silica gel or diatomaceous\nearth with sodium hypochlorite was carried out to elucidate\ntheir reactivity to aqueous chlorine. It was demonstrated\nthat the PAHs adsorbed on silica reacted more rapidly than\nthe PAHs themselves in water, leading to the formation\nof many chlorinated and oxidized derivatives. A similar reaction\nin the presence of potassium bromide was found to\npreferentially produce corresponding brominated derivatives.\nThese reactions seem to proceed through PAHs adsorbed\non the silica surface and halogenating agents, the\nelectrophilicity of which may be raised by the catalytic\neffect of the silanol group of the silica surface. These findings\nfrom the environmental viewpoint suggest that the\nreaction of hydrophobic compounds adsorbed on sediment\ncannot be neglected.