Effect of Phosphorus Modification on Cu-ZnO-Al_2O_3 for the Removal of H_2S

摘要

Cu-Zn-Al oxides adsorbents with or without phosphorus modification have been investigated for their hydrogen sulfide removal efficiency. Cu_(0.46)Zn_(0.48)/γ-Al_2O_3 was prepared by precipitating Cu and Zn nitrate precursors on unmodified and phosphorus-modified γ-Al_2O_3. For the preparation of Cu_(0.46)Zn_(0.48)/1P/γ-Al_2O_3, Cu_(0.46)Zn_(0.48)/3P/γ-Al_2O_3, and Cu_(0.46)Zn_(0.48)/9P/γ-Al_2O_3, the γ-Al_2O_3 was previously modified with different amounts of phosphorus (1,3, and 9 wt %, taken in the form of phosphoric acid) and Cu and Zn precursors were precipitated in the slurry of it. The sorbents were characterized by X-ray diffraction (XRD), surface area, pore size distribution, temperature-programmed reduction (TPR), Cu surface area measurement, and X-ray photoelectron spectroscopy (XPS). The sorbent modified with 3 wt % P on γ-Al_2O_3 showed the maximum value for the sulfur removal capacity and a large surface area of Cu. This high value of Cu surface area mainly results from making a sorbent with large pore diameter. Reduction in the binding energy of Cu 2P of the well-dispersed Cu metal particles, as observed by XPS analysis, could be the reason for the high sulfur removal capacity.