Microscale Mn2O3 Hollow Structures: Sphere, Cube, Ellipsoid, Dumbbell, and Their Phenol Adsorption Properties

Various Mn2O3 hollow structures, such as spheres, cubes, ellipsoids, and dumbbells have been synthesized through the following process: The surfaces of the prepared MnCO3 microspheres, microcubes, and microellipsoids were oxidized by KMnO4 to form a core/shell structure. Similarly, the surface of a dumbbell-like MnCO3 intermediate can also be oxidized by KMnO4. As the MnCO3 or MnCO3 intermediate cores were dissolved by acid, the MnO2 shells were formed. Calcining these MnO2 shells at 500 degrees C, polycrystalline Mn2O3 hollow structures were obtained. The morphologies of these hollow structures were similar to their precursors. The as-prepared hollow Mn2O3 materials were used as adsorbents in water treatment, and the hollow Mn2O3 spheres, cubes, ellipsoids, and dumbbells could respectively remove about 77%, 83%, 81%, and 78% of phenol.