Intercalation of metal-edta complexes in Ni–Zn layered hydroxysalts and study of their thermal stability

Acetate-containing nickel zinc layered hydroxysalts LHS-[Ni–Zn–AcO] have been exchanged with M2+-edta complexes (M2+Cu2+, Cd2+ and Mn2+) at different pHs. Upon a careful selection of the reaction conditions, a rather large concentration of metal chelate units in the interlayer space is achieved, as concluded from element chemical analyses, powder X-ray diffraction and FT-IR spectroscopy results.Thermal decomposition of the edta-intercalated compounds leads to dehydration and dehydroxylation of the hydroxide matrix and to the oxidative decomposition of the edta anion. Immediately after edta decomposition the solids loose their layered structure, forming solids with low external surface areas and moderate micro- and meso-porosity, which correspond to poorly crystallised phases of the corresponding metal oxides, as demonstrated by powder X-ray diffraction analysis.