Synthesis, characterization and adsorptive properties of hydrotalcite-like compounds derived from titanium rich bauxite

The synthesis of hydrotalcite-like compounds (HTlcs) containing Mg, Al and Ti using titanium-rich bauxite as one of the starting materials was described. The HT precursors and their calcined products were characterized by powder X-ray diffraction, TG-TDA, FT-IR and surface area measurements. Although the above characterization indicated the formation of hydrotalcite-like structure with good crystallinity, the presence of Ti4+ in the brucite layer was not confirmed. Calcination at 450 degrees C gave rise mainly to poorly crystalline MgO and amorphous mixed oxides, which can be reconstructed to their original structure by exposure to an aqueous solution. The calcined sample containing titanium showed relatively high adsorption capacity for fluoride and Cr2O72- as compared to that without titanium.