One-pot hydrothermal synthesis of hierarchical porous manganese silicate microspheres as excellent Fenton-like catalysts for organic dyes degradation

Towards bottlenecks demonstrated by typical Fenton-like catalysts in advanced oxidation processes (AOPs) for wastewater treatment, novel hierarchical porous ${\text{Mn}}^{\text{2+}}{\text{Mn}}_{\text{6}}^{\text{3+}}{\text{SiO}}_{\text{12}}$ (Mn₇SiO₁₂, MSO-12) microspheres (specific surface area: 434.90 m²·g⁻¹, pore volume: 0.78 cm³·g⁻¹) were rationally designed and achieved via a simple one-pot hydrothermal method (150 °C and 12.0 h) without any pre-prepared templates or organic solvents, by using abundant MnCl₂·4H₂O and Na₂SiO₃·9H₂O as the basic raw materials. The MSO-12 microspheres are confirmed as high-efficiency Fenton-like catalysts for degradation of organic dyes (methylene blue (MeB), Rhodamine B (RhB), and methyl blue (MB)) in the presence of H₂O₂, with impressively high specific consumption amount of MeB (R = 12.35 mg·g⁻¹·min⁻¹) and extremely low leaching of Mn (Mn_loss% = 0.27%). Simultaneously, the synergetic effect of adsorption and degradation on the superior removal of MeB is uncovered. The excellent recycling performances, especially the satisfactory removal of MeB from the actual water bodies (e.g., tap water and river water), as well as potential applications for degradation of RhB and MB enable the MSO-12 microspheres as a novel promising competitive candidate Fenton-like catalyst.