Facile Synthesis of Yolk-Shell Mn₃O₄ Microspheres as a High-Performance Peroxymonosulfate Activator for Bisphenol A Degradation

Manganese-based materials have been regarded as a kind of widely used heterogeneous catalysts for peroxymonosulfate (PMS) activation in water remediation. In this work, yolk-shell Mn₃O₄ (YS-Mn₃O₄) microspheres with a porous structure were synthesized by a simple hydrothermal method with manganese glycerate (Mn-GL) as a self-sacrificing template. YS-Mn₃O₄ exhibits high Brunauer-Emmett-Teller surface area (81.0 m²/g) and pore volume (0.18 cm³/g), which are essentially favorable for the development of its catalytic activity. When YS-Mn₃O₄ is employed as a PMS activator, it can exhibit good performance in the degradation of bisphenol A (BPA). Some influential parameters, such as catalyst dosage, oxone concentration, reaction temperature, BPA concentration, and pH value, and some inorganic ions have been analyzed in detail. Electron paramagnetic resonance examination and radical quenching results demonstrate that ^•OH and ^•SO₄ ^- should be responsible for the rapid decomposition of BPA in the YS-Mn₃O₄/PMS system. This work will be significant for tailoring the morphology of materials and arousing more attention to enhance the stability and reusability of catalysts.