The occurrence of common herbicides (Atrazine, ATZ and lodosulfuron, IDS), in waters presents potential risk to human and ecological health. The oxidative degradation of ATZ and IDS by ferrate(VI) (FeO42-)-O-VI, Fe(VI) is studied at different pH levels where kinetically observed second-order rate constants (kapp, M-1 s(-1)) decreased with increase in pH from 6.0 to 9.0. The determination of the rate constants for the Fe(VI) species, HFeO4- and FeO42-, with the herbicides using acid-base equilibria of Fe(VI) suggested that the HFeOZ species was largely responsible for the pH dependence behavior of kapp. The title herbicides degraded >90% within 10 min using excess weighted amounts of Fe(VI) over IDS (2:1) ATZ (20:1) and in the pH range of 6.0-9.0. Comparatively, degradations of ATZ and IDS by Mn(VII) were 70% and 40% under same conditions; - showing a superior efficiency of ferrate(VI) in degradation of toxic herbicides. The oxidized products of ATZ and IDS by Fe(VI) at a neutral pH were examined by liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis, which indicated that Fe(VI) attacked on the sulfonamide and alkyl chain moieties of ATZ and IDS, respectively. (C) 2015 Elsevier B.V. All rights reserved.