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  • 1 Departamento de Física, Universidade Federal de Sergipe, Campus Universitário, São Cristóvão, SE, 49100-000, Brazil
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Abstract

Alumina-based pigments were synthesized by the proteic sol–gel method. In this method, coconut water is employed as polymeric agent instead of the conventional alkoxide precursors. To this study, three common chromophore metallic ions (Mn3+, Co3+, and Cr3+) were chosen in order to verify the method efficiency. Differential thermal analysis (DTA), thermogravimetry (TG), and XRD techniques were used to characterize the synthesis process. The colorimetric characterization of the produced pigments was done according to the CIE-L*a*b* 1976 norm which is recommended by the CIE (International Commission on Illumination). The synthesized pigments presented intense and uniform colors in accordance to the literature results for each chromophore ion. The produced pigments also presented agglomerated with an average grain size of 180 nm when calcined at 800 °C.

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