No abstract

A series of MnO x /AC sorbents were prepared by a sub-or supercritical water impregnation method at different temperatures using three types of active carbons (ACs) as supports. The desulfurization activities of the MnO x /AC sorbents were studied, and the physicochemical properties of fresh and used sorbents were characterized by X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray absorption near edge structure. The results indicate that the AC composition and preparing temperature affect the desulfurization activity of prepared sorbent by changing the form and dispersion of the active component. MnO x /AC sorbent prepared at 350°C and active carbon AC(Z) from walnut shell as support presents the best desulfurization activity, holding above 22 h under the desulfurization level of nearly entire removing H 2 S in hot coal-based gas with breakthrough sulfur capacity of 7.24 g of S/100 g of sorbent. It is found that the valence of Mn loaded on the different AC supports was various, which related directly to the activity and capacity of the H 2 S removal from hot coal-based gases. The species, content, and the dispersion of the manganese oxide on the surface of the supports were dominated by AC properties. In addition, Mn 3 O 4 is the main active component for the H 2 S removal over MnO x /ACs sorbents.