Síntese e caracterização de hidróxidos duplos lamelares do sistema Mg - Al - NO³.

Abstract

VLamellar Double Hydroxides (HDLs) are known as allow a variety of anions among their coverslips to occupy. In literature are known as anionic clays, correlation with cationic clays. The HDL naturally occurring is known as hydrotalcite, but can be synthesized in the laboratory at low cost, in various compositions and properties. The objective of this work was to produce Mg - Al - NO 3 system HDLs, characterize them by X-ray Diffraction (XRD) and Infrared spectroscopy (FTIR). The syntheses were performed by co-precipitation at variable pH and constant pH. In the synthesis with decreasing variable pH constituted addition of bivalent and trivalent cations (Mg 2+ and Al 3+) in a hydroxide solution of ammonium. Already performed at constant pH, in addition to dripping the cation solution, another solution of ammonium hydroxide was dripped concomitantly. The obtained HDLs were characterized by DRX and FTIR held at the University's Fuel and Materials Laboratory (LACOM) Federal of Paraíba (UFPB). XRDs showed the formation of crystalline compounds. identified as HDLs in which the interlamellar anion is nitrate. Differences were noted with regard to the method used, where HDL produced at variable pH was more crystalline. FTIR analysis confirmed the presence of nitrate in the materials produced. The results showed the efficiency of the method used, which avoids contamination by carbonate intercalation. The many possibilities in the chemical composition of HDLs Gives this class of materials wide range of application.