Monopersulfate oxidation of tetrabromobisphenol A by an iron(III)-phthalocyaninetetrasulfate catalyst coordinated to imidazole functionalized silica particles

•FePcTS was supported on imidazole functionalized silica (IPS) via coordination.•TOF of TBBPA oxidation for FePcTS/IPS was larger than that of FeTPPS/IPS.•The oxidation of TBBPA for FePcTS/IPS was affected by adding a radical scavenger.•The higher TOF in FePcTS is due to participation of radicals in TBBPA oxidation.

An iron(III)-phthalocyaninetetrasulfate (FePcTS) was axially coordinated to a series of imidazole functionalized silica, 3-(1-imidazolyl)propylcarbamoyl-3′-aminopropylsilica (IPS) particles. Among the prepared FePcTS/IPS catalysts, catalytic activity for the oxidation of tetrabromobisphenol A (TBBPA) for the smallest sized particle (<30 μm) was more effective than larger sizes (145 μm< and 45–145 μm). The catalytic activity of FePcTS/IPS was compared with that of a structural analogue, iron(III)-tetrakis(p-sulfonatephenyl)porphyrin (FeTPPS) supported IPS (FeTPPS/IPS). The TOF values for the oxidation of TBBPA by FePcTS/IPS (11–17 h−1) were much larger than the corresponding values for FeTPPS/IPS (0.7–3.5 h−1) in the absence and presence of humic acid, a major coexistent substance in landfill leachates. To investigate the reasons for the differences in catalytic activities between the FePcTS and FeTPPS systems, the influence of ethanol, a SO4− scavenger, on the oxidation of TBBPA oxidation was tested. The TOF values for FePcTS/IPS decreased with increasing ethanol concentration, while the catalytic activities for FeTPPS/IPS were not affected by adding ethanol. These results suggest that the higher catalytic activity of the FePcTS catalytic system can be attributed to the contribution of radical species, which can be generated via the homolysis of OO bonding in the Fe(III)-peroxo species.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (161 K)Download as PowerPoint slide