Recycling of red mud as a catalyst for complete oxidation of benzene

HCl-treated red muds, HRMs, are better catalyst than the calcined red mud, CRM. Moreover, for the HCl treatment, the catalytic activity depends on the solution pH applied. [Display omitted] •Waste red mud (WRM) was reused as a potential catalyst for environmentally benign catalytic applications.•Catalytic activity of the WRM depends on pretreatment methods, support type and Pd loading.•Water vapor greatly inhibited the catalytic activity of the red mud based catalysts. In this work, we investigated waste red mud (WRM) generated from industrial processes as a potential catalyst support for the complete oxidation of toxic organic compounds. Two different types of red mud based catalysts were prepared using calcination (CRM) and hydrochloric acid aqueous solution (HRM) pretreatments. In addition, HRMs loaded with different amounts of palladium were prepared and examined for their catalytic behaviors. For comparison, aluminas (γ-Al2O3) loaded with different amounts of palladium were also used. The catalyst samples prepared were characterized by using nitrogen adsorption, ICP-AES, TPR, XRD, FT-IR, and FE-TEM to examine their textural and chemical characteristics. The catalytic activity of the samples used depended on the pretreatment techniques applied, lattice oxygen mobility, the type of supports, and the loading amount of palladium. It was also interesting to note that water vapor in the feed stream inhibits catalytic activity for the complete oxidation of benzene.