Oxidative degradation of pentabromophenol in the presence of humic substances catalyzed by a SBA-15 supported iron-porphyrin catalyst

•The FeTPyP catalyst was supported on SBA-15 to degrade PBP in the presence of HS.•The kinetics of PBP degradation was somewhat inhibited in the presence of HSs.•The FeTPyP-SiO2 catalyst was synthesized as a control catalyst.•The inhibition by HS was largely reduced by FeTPyP-SBA-15 compared with the control.•This is due to the size selectivity by orderly porous structure of FeTPyP-SBA-15.

Pentabromophenol (PBP), a widely used brominated flame retardant, is found in landfill leachates, and humic substance (HS) is a major concomitant in leachates. To suppress the inhibition of HS for the oxidative degradation of PBP by a heterogeneous catalytic system, a mesoporous molecular sieve SBA-15 supported iron(III)-5,10,15,20-tetrakis(4-pyridyl)-porphyrin (FeTPyP-SBA-15) was synthesized and applied to the degradation of PBP using KHSO5 as an oxygen donor. The prepared FeTPyP-SBA-15 showed a high catalytic activity and 50 μM of PBP was efficiently degraded at pH 7 and 8 using 125 μM KHSO5 even in the presence of 50 mg L−1 HS. SiO2 supported FeTPyP (FeTPyP-SiO2) was synthesized as a control catalyst, and the turnover frequency for the FeTPyP-SiO2 catalyst (16.7 h−1) was smaller than that for FeTPyP-SBA-15 (58.3 h−1) in the presence of 25 mg L−1 of HS. These results show that the FeTPyP-SBA-15 catalyst has a higher catalytic activity for the degradation of PBP in an aqueous solution containing HS. The FeTPyP-SBA-15 had a high selectivity for the catalytic degradation of PBP and the orderly porous structure of FeTPyP played a key role in decreasing the adverse effect of the HSs.

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