Preparation and desulfurization performance of various MnOx materials for ship exhaust emissions control

Sulfur dioxide (SO2) emissions from ship exhaust pose a serious threat to the environment and human health. In this study, various manganese oxide (MnOx) samples with different physical and chemical structures were prepared using template, precipitation, ball milling, calcination, and microwave methods for the desulfurization of ship exhaust. The MnOx samples were characterized intensively through scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analysis. The desulfurization performance was measured via thermogravimetry, and the desulfurization mechanism of the different MnOx samples was investigated. Results showed that the desulfurization performance of MnOx was determined by the comprehensive influence of the material's pore structure, specific surface area, crystal structure, Mn valence content, and reaction temperature. The pore structure in MnOx considerably affected the desulfurization performance of MnOx. In our experiment, tp-MnOx prepared using the template method presented a rich 3D pore structure, a large specific surface area, and excellent desulfurization performance. At 400 degrees C, the average SO2 capture rate of tp-MnOx in the first hour was 0.283 g(SO2)/g(material)center dot h. The highest SO2 capture rate of tp-MnOx was 0.694 g(SO2)/g(material) observed at 500 degrees C.