Effect of phosphorus modification on Cu-ZnO-Al2O3 for the removal of H2S

Cu-Zn-Al oxides adsorbents with or without phosphorus modification have been investigated for their hydrogen sulfide removal efficiency. Cu0.46Zn0.48/gamma-Al2O3 was prepared by precipitating Cu and Zn nitrate precursors on unmodified and phosphorus-modified gamma-Al2O3. For the preparation of Cu0.46Zn0.48/1P/gamma-Al2O3, Cu0.46Zn0.48/3P/gamma-Al2O3, and Cu0.46Zn0.48/9P/gamma-Al2O3, the gamma-Al2O3 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 gamma-Al2O3 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.