Síntese de hidróxidos duplos lamelares do sistema Cu, Zn, Al-Co2: propriedades morfológicas, estruturais e comportamento térmico

Abstract

Hydrotalcites are anionic clays, also known as layered double hydroxides (LDH), which have structure formed by stacking layers of mixed hydroxides of divalent and trivalent cations with hydrated anions in the spaces between those layers. Your structure is similar to brucite mineral. This compounds can be represented by general formula: M2+ 1- x M3+ x (OH)-1 2 Anx/ n yH2O, where M2+ represents the bivalent cation, M3+ represents a trivalent one and An- an anion with n- charge. The LDHs of system Cu, Zn, Al – CO3 were synthesized in the laboratory under conditions that favor the formation of small crystals of high surface area. The characterization was made by X-ray diffraction, thermogravimetric analysis, infrared spectroscopy and scanning electron microscopy (SEM). The syntheses were based on co-precipitation method, under different synthesis conditions (hydrothermal bath; tritation time), using copper and zinc sulphate, aluminum and sodium hydroxide solutions, all with analytical grade. The compounds synthesized have high crystallinity, the intensity of its peaks prove that the materials have been well organized and stacked with the lamellae. The objective of this work was to synthesize and characterize layered double hydroxides with Cu, Zn, Al – CO3 system, analyzing morphological and structural properties and your thermal behavior through variable synthesis conditions.