BENZENE AND TOLUENE INFLUENCE WITH OR WITHOUT NITROGEN-DIOXIDE ON INORGANIC PIGMENTS OF WORKS-OF-ART

The interaction of benzene and toluene on five known pigments, namely ZnO, PbO, Fe2O3 Cr2O3 and TiO2 has been studied, in the presence as we ll as in the absence of nitrogen dioxide. The following physicochemica l constants have been determined and therefore the materials' behaviou r in such a polluted atmosphere is concluded: (1) the dynamic adsorpti on rate constant of the analyte pollutant, describing its experimental isotherm on the surface of the material varying with the time; (2) th e desorption rate constant of the pollutant from the solid surface;(3) the rate constant of a possible surface reaction of the adsorbed anal yte (first or pseudo-first order); (4) the overall deposition velocity of the pollutant; (5) the reaction probability of the pollutant on th e material; and (6) the apparent rate constant of a possible chemical reaction of each aromatic pollutant with nitrogen dioxide, taking plac e above the material and simultaneously with the heterogeneous one. Th e contribution of the above parameters to the elucidation of the mecha nism of deterioration of various works of art in museums is significan t, as one can see. (C) 1998 Elsevier Science Ltd. All rights reserved.