Bio-silica coated with amorphous manganese oxide as an efficient catalyst for rapid degradation of organic pollutant

A novel rapid green one-step method is developed for the preparation of bio-silica coated with amorphous MnO2 nanoparticles by treating bio-silica with an acidic permanganate solution. The method developed has the advantage of selectively coating the surface of either one or both sides of the porous silica structure with a thin catalytic active amorphous MnO2 layer in a controlled way. The uncoated and MnO2 coated bio-silica are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The catalytic activity of amorphous MnO2-coated bio-silica is examined by degrading organic dye at ambient condition. The as-synthesized samples show highly efficient and rapid degradation of Rhodamine B. The simplicity and cost-effectiveness of the materials and method can be very useful for highly efficient degradation of organic pollutants for environmental remediation.

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► Nanoclusters of amorphous δ-MnO2 material and MnO2 coated bio-silica were produced.
► The coating of the bio-silica surface is effectively controlled.
► Catalytic degradation of Rhodamine B by the as-synthesized materials was completed.
► Porous structure of bio-silica improves the catalytic of MnO2-bio-silica nanocomposite.