Cobalt-modified Brazilian bentonites: Preparation, characterisation, and thermal stability

The thermal effect on the phase evolution and crystallinity of raw and cobalt-modified Brazilian bentonites was investigated. The modified bentonites were prepared dispersing the bentonite particles in Co2+ hydroxide gels. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermal analyses and energy dispersive X-ray spectroscopy. An endothermic peak around 900°C indicated the formation of olivine. A test with benzyl alcohol confirmed the catalytic activity as acidic catalyst for alcohol oxidation. ► A modification of Brazilian bentonites through the addition of a cobalt gel, was proposed. ► Modified-bentonites are thermal stables until 600°C. ► Cobalt-bentonites presented catalytic activity as acid catalyst in alcohol oxidation reactions.