Homogeneous photocatalytic mineralization (decomposition to carbon dioxide (CO2)) of acetic acid in dilute aqueous solutions of various metal ions was examined at room temperature under irradiation of UV light in the presence of oxygen (O-2). Iron ton exhibited a much higher level of activity among the metal ions studied for mineralization of acetic acid. The rate of CO2 formation was proportional to first-order partial pressure of O-2 and concentrations of iron ion and acetic acid, whereas the rate was in inverse proportional to first-order proton concentration The rate equation, r = k Po-2 [[Fe-III(H2O)(6)](3+)] [AcOH][H+](-1), in overall photocatalytic mineralization of acetic acid was derived from these results The mechanism of the photocatalytic mineralization of acetic acid in an aqueous solution of ion was proposed (C) 2010 Elsevier B V All rights reserved