Enhanced degradation performance of bisphenol M using peroxymonosulfate activated by zero-valent iron in aqueous solution: Kinetic study and product identification

In the present work, we first examined the performance of zero-valent iron (Fe 0 ) activated peroxymonosulfate (PMS) for the removal of that bisphenol M (BPM). In 90 min, 95.9 ± 1.0% of BPM (initial concentration of 10 μM) could be removed in the optimal reaction conditions: [BPM] 0 :[PMS] 0  = 1:40 (molar ratio), [PMS] 0 :[Fe 0 ] 0  = 1:3 (molar ratio), pH = 8.0 (maintained by 0.1 M phosphate buffer solution), T = 35 °C. Common environmental ions like HCO 3 − , Cl − , NO 3 − accelerated BPM degradation while NH 4 + hindered it. In radical quenching tests, sulfate radicals (SO 4 − ) were found to play a dominant role in BPM degradation, while hydroxyl radicals ( OH) were also detected. By high-performance liquid chromatography–tandem mass spectrometry analysis, 13 products of BPM including small molecules, oligomers and hydroxylated derivatives were identified, and five possible degradation pathways were then proposed. The predicted acute toxicity of the reaction products was reduced after BPM was treated by Fe 0 /PMS. All these results prove that Fe 0 /PMS is an efficient, convenient, and environmentally friendly treatment method for the removal of BPM.