Ferrate(VI) (Fe(VI); (FeO42-)-O-VI) could be activated by adding simple acids (HCl, HNO3, and acetic acid) to the Fe(VI)-contaminant mixed solution in deionized water (or unbuffered water) under slightly alkaline pH conditions. Activation of Fe(VI) resulted in increased oxidative transformation of caffeine (psychostimulant, CAF), acesulfame potassium (artificial sweetener, ACE), and atenolol (beta-blocker, ATL) by 30% within in seconds to minutes. Moreover, without acid addition to Fe(VI)-contaminant solution (un-activated Fe (VI)), the transformation of contaminants occurred in minutes to hours at similar pH conditions. CAF and ACE could be removed almost completely by activated Fe(VI). In the case of ATL, which was recalcitrant to Fe(VI) alone, the enhancement by activated Fe(VI) was also seen. A possible reason for the augmentation of oxidative transformation of organics may be the increasing formation of reactive intermediate species, Fe-V/Fe-IV, in the Fe(VI)-contaminant-acid mixed solution. Acid-activated Fe(VI) could decontaminate the sluggishly reactive or non-reactive pollutants by involving Fe-V/Fe-IV species, which increased electron equivalents per Fe(VI) (i.e. oxidation capacity) in oxidation processes to achieve higher removal efficiencies at reduced amount of Fe(VI) and shorter reaction times, than non-activated Fe(VI). The findings have greater implications in purifying pollutants in water. (C) 2016 Elsevier B.V. All rights reserved.