Synthesis and characterisation of hydrotalcites produced by an aluminium hazardous waste: A comparison between the use of ammonia and the use of triethanolamine

Hydrotalcite-like compounds were co-precipitated with diluted sodium hydroxide from an unconventional aluminium source: the aluminium waste generated by the tertiary aluminium industry, with the assistance of ammonia and triethanolamine at pH 10. These products were characterised by several techniques (XRD, FT-IR, UV¿vis-NIR, SEM, DTA-TG and BET methods) to compare results. The characterisation of products confirmed significant differences depending on basic reagent selected. Products co-precipitated with ammonia showed less crystal growth, a more significant iron content in the structure and higher internal surface area. Products from triethanolamine showed the entry of organicmolecules into the layered structure. These findingswere important for the improvement of methods based on waste treatment, transforming an aluminium hazardous waste into a value added product as layered double hydroxides.The authors would like to thank the company Metalquex, S.L. (Zaragoza, Spain) for supplying wastes, and CSIC for the financial support (P.I.E. 201260E115). They also gratefully acknowledge the assistance provided by Dr. Blanca Casal for helpful discussion during this research, and especially to Professor Guillermo Monrós (UJI) for allowing us to record the UV–vis-NIR spectra.Peer Reviewe