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Hydroxy-Chromium Smectite: Influence of Cr Added

Published online by Cambridge University Press:  28 February 2024

C. Volzone
C. Volzone*
Affiliation:
Centro de Tecnología de Recursos Minerales y Cerámica, Cno. Centenario y 506, CC 49 (1897), M.B. Gonnet Buenos Aires, Argentina. FAX 54-21-710075
*
a54-21-710075
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Abstract

OH-Cr smectites were prepared with different mmol Cr/g smectite: 0.5, 1.5, 3.5, 5, 10 and 20 by treatment with hydroxy-chromium solution prepared at 60°C and one day of hydrolysis with OH/Cr = 2. The samples were characterized by X-ray diffraction (XRD), differential thermal analyses (DTA) and N2 adsorption-desorption isotherms.

The d(001) spacings of OH-Cr-smectite were different according to Cr added/g smectite. Larger d(001) spacings: 1.95, 2.05 and 2.07 nm were obtained with 5, 10 and 20 mmol Cr per gram of sample. DTA diagrams of smectite treated with OH-Cr solution showed exothermic peak at 420°C corresponding to Cr203 (confirmed by XRD). N2 adsorption-desorption isotherms of smectite treated with different amounts of Cr preserved the same slit-shaped pores than original sample, but with different micropore volume. This behavior was maintained until treatment temperature of 380°C. The specific area of smectite was increased from 36 to 175 m2/g after treatment with OH-Cr solution. The textural characteristics of OH- Cr smectite heated up to 420°C were changed. The specific area decreased and mesopore volume was produced. The different Cr added modified the structural and textural behavior.

Keywords

DTAPillared claysSmectiteXRD
Type
Research Article
Information
Clays and Clay Minerals , Volume 43 , Issue 3 , June 1995 , pp. 377 - 382
Copyright
Copyright © 1995, The Clay Minerals Society

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