Reactive Black-5 solutions were oxidized in batch mode with persulfate activated by zero valent iron. Oxidation is conducted in batch mode and different parameters like pH iron and persulfate dosages were examined. Oxidation of dye solutions was observed at a medium pH of 3. Oxidation of dye solutions with presence of zero valent iron and persulfate was not significant at neutral and basic conditions. It is observed that in acidic conditions zero valent iron is dissolved in solution and sulfate radicals are generated through homogeneous catalysis mechanism. Zero valent iron dosages between 0.05 and 0.4 g/L were examined with dye to persulfate molar ratio of 1:10. It is observed that iron amount did not affect the color removal efficiency while increasing persulfate concentration improved color removal efficiency. Zero valent iron activated persulfate oxidation was also compared with homogeneous iron enhanced persulfate oxidation where homogenous oxidation was found to be more efficient in decolorization of reactive black-5 solutions.