BENDINELLI, E. V. ; AOKI, I. V. ; Margarit-Mattos, I.C.P. .
Resumo: This work aims the evaluation of the Layered Double Hydroxide (LDH) treatment and characterization for molybdate storage, focusing on smart organic coatings use. Commercial hydrotalcite (HT), which underwent several treatments, was the used LDH. First, HT was calcined and then reconstructed in water, terephthalic acid or glycerol followed by an interlamellar anion substitution with molybdate. The reconstruction was tried also directly in a molybdate aqueous solution. The LDHs SEM analyses have evidenced a lamellar morphology. The XRD have shown that the lamellar structure reconstruction, after calcination, was more efficient when terephthalic acid and glycerol were used, showing the structure memory effect. The molybdate release concentration was monitored by ion chromatography in double-distilled water and NaCl solution. The higher molybdate release, in solutions containing chlorides, indicates an anionic exchange property with different kinetics in terephthalic acid (HTCTe-Mo) and glycerol (HTCGl-Mo) reconstructed LDHs. Furthermore, the release process was accelerated by solution temperature, doubling the molybdate amount released at 85°C in comparison with 150 C. Electrochemical impedance spectroscopy (EIS) and anodic polarization curves of carbon steel, in aqueous extracts of molybdate loaded LDHs, have shown moderate inhibitory efficiency of the molybdate in 3.5 wt. % NaCl.
