The preparation of metal catalysts has been studied by using four industrial wastes, two coming from a textile company (sludge and ash) and two collected from an automotive company (two different types of sludge). The wastes have been characterized by atomic absorption, XRD, and XRF to determine the metals and the crystalline phases present, and they have been mixed with different proportions of V2O5 for hydrothermal synthesis of various families of catalysts. All the synthesized catalysts, as well as the dry wastes subjected to calcination process, have been tested in the oxidative dehydrogenation of propane, and excellent results have been obtained: conversions close to 20% with recrystallized catalysts without V and selectivities higher than 90% and up to 95% with catalysts having V2O5/waste ratio of 1:1. The results highlight the potential benefits of using dangerous wastes with high contents of heavy metals for the synthesis of commercial catalysts.

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