The photodegradation of octafluorodibenzo-p-dioxin (OFDD) in a water/acetonitrile (v/v = 4:1) mixture was here investigated for the first time in the presence of Fe(II) and potassium monopersulfate (PMS) under DV (lambda = 365 nm) irradiation. The degradation efficiency was found to depend on the presence of UV irradiation, and on the initial concentrations of PMS and Fe(II). OFDD with an initial dosage of 1 mg L- 1 as successfully removed by UV/Fe(II)/PMS with OFDD:PMS:Fe(II) = 1:30:5 M ratio within 10 min irradiation. The effects of humic acid, bicarbonate, chloride and solution pH were also evaluated. The degradation process of OFDD by UV/Fe(II)/PMS can be initiated by an oxidative attack of hydroxy radical on carbon atoms in the aromatic ring, the electron transfer reaction of sulfate radical with OFDD and a direct C-O bond homolysis of OFDD. The intermediates and products of OFDD photodegradation were analyzed by using LC/MS technique and the associated photochemical pathway was proposed. The combined process with Fe(II), PMS and UV could be a useful technology for the treatment of wastewater containing OFDD. (C) 2017 Elsevier B.V. All rights reserved.