Z. Phys. Chem. 216 (2002) 1311–1321  by Oldenbourg Wissenschaftsverlag, München Physicochemical Characterization of Inorganic Pigments in the Presence of Gaseous Pollutants. The Role of Ozone By V. Siokos, J. Kapolos and F. Roubani-Kalantzopoulou ∗ National Technical University, Department of Chemical Engineering, 9. Iroon Polytechniou St., 157 80 Zografou, Athens, Greece (Received March 13, 2002; accepted in revised form July 2, 2002) RF-GC Technique for Physicochemical Measurements / Inorganic Pigments / Synergistic Effects / Ozone and Hydrocarbons / Homogeneous and Heterogeneous Reaction / Non-Linear Adsorption Isotherm The Reversed–Flow Gas Chromatography technique was used to study the interaction of volatile hydrocarbons on three inorganic pigments, namely, CdS, ZnS and Cr 2 O 3 in the presence and the absence of ozone. By using an experimental adsorption isotherm, not necessarily linear, the following physicochemical constants have been determined: (1) the dynamic adsorption rate constant of the pollutant on the surface of the material, (2) the desorption rate constant of the pollutant from the solid surface, (3) the rate constant of a possible surface reaction (first or psedo-first order), (4) the overall deposition velocity of the pollutant, and (5) the reaction probability of the pollutant on the solid material. By the above parameters, the behavior of the inorganic pigments in a polluted atmosphere is described. 1. Introduction The atmospheric pollution is one of the main reasons for the deterioration of the solid materials. The atmospheric pollutants such as the volatile hydro- carbons, nitrogen dioxide and ozone attack the exterior surfaces of historical buildings and monuments and fatefully damage them. There is no way to stop the atmospheric pollution, so all the efforts focus on the protection of the works of art by cover them with materials able to stop or to decelerate the corrosion. On the other hand, not only one pollutant affects the materials but two or three together and also secondary pollutants that are produced by chemical reactions between primary pollutants. * Corresponding author. E-mail: roubanif@central.ntua.gr