Bendinelli, E.V. ; ROCHA, A. C. ; Barcia, O. E. ; Aoki, I.V. ; MARGARIT-MATTOS, I. C. .
Resumo: Effects of lamellar reconstruction methods in the release of molybdate ions encapsulated in Layered Double Hydroxides (LDH) are evaluated. The methodology consisted of two stages: i) treatment of LDHs and interlayer substitution with molybdate; ii) characterization of morphology and kinetics of molybdate release in chloride solution and deionized water. Commercial hydrotalcite (HT) was calcined and then reconstructed in water (HTCCa), terephthalic acid (HTCTe), glycerol (HTCGl) and in molybdate solution (HTCMo). XRD showed that lamellar reconstruction succeeded only with HTCCa, HTCTe and HTCGl. Afterwards, substitution of interlamellar anions by molybdate was done. Molybdate release over time, monitored by ion chromatography, was higher in chloride solution suggesting ion exchange. Increasing temperature to 85 °C doubled the molybdate released by HTCTe-Mo, accelerating the kinetic process compared with room temperature. The kinetics release was different for each LDH doped with molybdate. Gradual liberation of molybdate characterizes HTCTe-Mo while HTCGl-Mo promotes quick release. Therefore by the choice of reconstruction routes it is possible to modulate the liberation of molybdate by LDH.
