Activation of persulfate by Fe(III) species: Implications for 4-tert-butylphenol degradation

In this study, the activation of persulfate induced by Fe(III) species, including 5 kinds of iron oxhydroxides (IOs) and dissolved Fe3+ under dark condition were investigated. Ferrihydrite (FH) and akaganeite (AK) showed the highest activity in 4-tert-butylphenol (4tBP) removal. The 4tBP degradation rate constant decreased as the solution pH increased from pH 3.2 to 7.8 in FH/S2O82− system. However, the pH value had no significant effect on the 4tBP degradation in AK/S2O82− system. The degradation of 4tBP in Fe3+/S2O82− system was also performed to investigate the role of ferric species in persulfate activation. The pH dependency of 4tBP degradation rate was closely related to the speciation of FeIII, whereas the Fe(H2O)63+ was found to be the most active soluble iron complex form in the activation of S2O82−. 4tBP degradation was mainly due to the SO4− in IOs/S2O82− system, while SO4− and HO2 both had great contribution on 4tBP degradation in Fe3+/S2O82− system. Further investigations showed clearly that 4tBP degradation efficiency was decreased significantly due to the trapping of SO4− by chloride. This finding may have promising implications in developing a new technology for the treatment of contaminated waters and soils, especially where Fe3+ species are naturally occurring.