Oxidation of amaranth dye by persulfate and peroxymonosulfate activated by ferrocene

Background Readily‐available and efficient catalysts are preferable for activating oxidants such as persulfate (PSF) and peroxymonosulfate (PMS) for environmental remediation. Ferrocene (Fc), a stable and non‐toxic Fe2+‐bearing compound, is a promising heterogeneous catalyst for activation of PSF/PMS, that has not been previously investigated. In this study, the activation of PSF/PMS by Fc is evaluated using the oxidation of toxic amaranth dye as a model reaction. Results While an insignificant amount of amaranth dye was removed by Fc or PSF/PMS separately, the combination of Fc and the oxidants completely decolorized amaranth dye, indicating that Fc activated PSF/PMS. Fc‐activated PMS was found to be much more effective than Fc‐activated PSF for degrading amaranth. Elevated temperatures improved the degradation efficiency and kinetics, while the activation of PSF/PMS remained consistent under acidic conditions. Through examining the effects of inhibitors and electron paramagnetic resonance analyses, Fc was proven to activate PSF/PMS to generate sulfate radicals. Fc could also be re‐used for multiple cycles to activate PSF and PMS. Conclusion Fc remained intact after the activation according to X‐ray diffraction, FT‐IR and X‐ray photoelectron spectroscopy analyses. These features make Fc an effective and readily‐available heterogeneous catalyst to activate PSF and PMS for advanced oxidation processes (AOPs). © 2016 Society of Chemical Industry