ZnS/AC sorbent derived from the high sulfur petroleum coke for mercury removal

Abstract

Porous carbon-based sorbents are considered as one of the most promising materials for solving atmospheric mercury pollution. In this study, a novel porous carbon-based sorbents ZnS/AC were prepared from high sulfur petroleum coke (HSPC) and zinc nitrate by in-situ method. The as-prepared ZnS/AC sorbents were characterized by BET, XRD, ICP-OES and XPS analyses, and the element mercury removal performance of these sorbents from the simulated coal derived fuel gas were evaluated using a bench-scale fixed-bed reactor. The effects of atmospheres and temperatures on the Hg0 removal performance of ZnS/AC sorbents were also studied. The mercury removal efficiency could maintain above 84% within 4 h at ≤120 °C under N2 + H2 + H2S atmospheres. The higher temperature was not conducive to mercury removal. The average mercury removal efficiency was only 30% within 2 h at 180 °C. Hydrogen sulfide (H2S) significantly improved the mercury removal performance of the ZnS/AC sorbent, while the concentration of H2S hardly affected the mercury removal efficiency. The mercury removal efficiency of the regenerated ZnS/AC sorbents after mercury capture still maintained above 85% within 6 h at 120 °C after three cycles of capture-regeneration, it can be concluded that ZnS/AC sorbent is a promising and efficient sorbent for removing elemental mercury from fuel gases.