Confocal Fluorescence Microscopy and Kinetics of the Cr 3+-Chromate Ion Oxidation Equilibria at the Solid Liquid Interface

Silica-borax pearl samples impregnated with 0.17 and 0.64% Cr3+ were characterized by specific surface area measurements, UV-Vis spectroscopy, energy-dispersive X-ray fluorescence and laser-scanning confocal microscopy. Pearl stability against oxidizing conditions was tested by adding samples to an aqueous hydrogen peroxide solution. The reaction was examined by UV-Vis spectroscopic measurements of the supernatant and laser-scanning confocal microscopy images of the substrate. Overall, hydrogen peroxide-induced Cr3+ to Cr6+ oxidation across the solid-liquid interface promoted solid matrix cleavage pearl degradation and concomitant formation of multiple scattering centers was observed. A dual-detection scheme was employed in the confocal microscopy measurements allowing us to separate scattering and absorptive contributions to the observed signals. The confocal microscopy images indicate that Cr3+ oxidation induced by hydrogen peroxide solutions occurs throughout the entire pearl sample and indicate that oxidation reactions induce leakage of chromate ion into aqueous solutions.

Bibliographic Details

Main Authors:	Almerindo,Gizelle I., Gaborim,Anika P. A., Nicolazi,Lucas M., Idrees,Muhammad, Nome,Faruk, Fiedler,Haidi D., Nome,Rene A.
Format:	Digital revista
Language:	English
Published:	Sociedade Brasileira de Química 2017
Online Access:	http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532017000901708
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