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Type: Artigo de periódico
Title: Zro2 Thin Film Grafted On Silica Gel Surface: Preparation And Cr(vi) Adsorption Property [filme Fino De Zro2 Enxertado Sobre A Superfície De Sílica Gel: Preparação E Propriedade De Adsorção De Cr(vi)]
Author: Lazarin A.M.
Borgo C.A.
Gushikem Y.
Abstract: The present experiment describes an easy procedure for obtaining SiO2/ZrO2 by reacting ZrOCl2 with SiO2 with the following characteristics: SBET = 500 m2 g-1 and an average pore diameter of 6 nm. The material obtained presented 1.3 wt% ZrO2 content corresponding to 140 μmol g-1. The average density of ZrO2 onto SiO2/ZrO2 matrix is 2.8×10-11 mol cm-2. The adsorption isotherm for Cr(VI) showed a maximum of adsorption value (200 μmol g-1) at pH 2. The adsorption can be described by the reaction: =Zr(OH)2 + 2HCrO4 - + 2H+ ⇄ [(=Zr(OH2 +)2) (HCrO4 -)2]. Above the zero point of charge, i.e. pH > 5.5 due to the surface charge inversion, desorption of Cr(VI) occurs according to the reaction: [(=Zr(OH2 +)2) (HCrO4 -)2] + 6OH ⇄ (=ZrO2)2- + 6H2O + 2CrO4 2-.
Citation: Quimica Nova. , v. 25, n. 3, p. 499 - 501, 2002.
Rights: aberto
Date Issue: 2002
Appears in Collections:Unicamp - Artigos e Outros Documentos

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