Heterogeneous activation of peroxymonosulfate using superparamagnetic β-CD-CoFe₂O₄ catalyst for the removal of endocrine-disrupting bisphenol A: Performance and degradation mechanism

The unintended leakage of endocrine-disrupting bisphenol A (BPA) from different industries into the aquatic environment has posed a severe threat to aquatic lives and human health. Herein, we explored a hydrothermal method to synthesize superparamagnetic β-cyclodextrin-cobalt ferrite (β-CD-CoFe₂O₄) catalyst for the selective capturing and efficient degradation of BPA through heterogeneous activation of peroxymonosulfate (PMS). The as-prepared catalysts were systematically characterized through multi-techniques to explore the relationship between their catalytic performance and material properties. Results showed that, in β-CD-CoFe₂O₄/PMS system, the degradation rate of BPA reached 99.23% in 60 min with a rate constant of 0.0708 min⁻¹, approximately 16.09 times than CoFe₂O₄/PMS system (0.0044 min⁻¹). Specifically, the large surface area and availability of more reactive sites of β-CD-CoFe₂O₄ boosted the activation process of PMS compared to pristine CoFe₂O₄, thus enhancing the degradation of BPA. Meanwhile, the effect of different operational parameters and co-existing anions on BPA degradation were also investigated. The generation of free radicals (SO₄^∙-,∙OH,O₂^∙-,and1_O2)in the β-CD-CoFe₂O₄/PMS system liable for reducing BPA was corroborated through electron paramagnetic resonance analysis and quenching experiments. The possible degradation pathways of BPA were proposed based on the identification of reaction intermediates formed during the mineralization process. In brief, the findings of this study suggested that β-CD-CoFe₂O₄ is an efficient and environmentally friendly catalyst that facilitated the degradation of BPA through PMS activation. Moreover, the excellent magnetic separation, stability, and reusability of the β-CD-CoFe₂O₄ catalyst make them promising candidates for their water purification applications.