Characterization by temperature programmed techniques of spent and acid treated vanadium catalysts

spent samples of v2o5/sio2-γal2o3 catalyst used for h2so4 production were acid treated to recover vanadium. fresh, spent, and acid treated samples were characterized by temperature-programmed techniques: tpr-h2, tpo-o2, tpd-nh3 and, tga-dta in order to determine the effect of deactivating species on vanadium recovery. drx and uv-vis techniques were used to confirm several signals from the temperature-programmed profiles. the results suggest that vanadium sulfovanadates and oxides in treated samples strongly interact with the support making it difficult to get more than 86% vanadium recovery.