Regeneration of Spent Catalysts by H2O2 Chemical Treatment

This study investigates the regeneration of spent Ti/Zn, Cu/Mn, and Pt/Pd catalysts with 0.01 N H2O2 chemical treatment. The conversion efficiencies of C3H6 by Ti/Zn, Cu/Mn, and Pt/Pd catalysts were significantly improved from 22%, 35% and 63% to 60%, 50% and 85%, respectively after regeneration. Chemical regeneration of spent catalysts by H2O2 was effective to remove the poisons caused by the organic carbons, sulfides and chlorides, but the concentrations of H2O2 should be carefully controlled to avoid the over oxidation and erosion. The BET surface areas or pore volumes of regenerated catalysts were increased, and the XRD peak intensities of metal sulfides (Ti3S4, ZnSO4, CuS, Cu2S, MnS2, MnS, PtS2) and chlorides (TiCl3, ZnCl2, MnCl2, PtCl2, PtCl4, PdCl2) in regenerated catalysts were reduced or disappeared. These metal sulfides and chlorides were converted to metal oxides (TiO2, Ti3O5, ZnO, ZnO2, CuO, Cu4O3, MnO2, Mn3O4, PtO2, Pt3O4, PdO).