A study of acidity and structure of hydroxy-Cr intercalated bentonites

被引:7
作者
Bandosz, TJ [1 ]
Jagiello, J [1 ]
Schwarz, JA [1 ]
机构
[1] UNIV MIN & METAB,FAC FUELS & ENERGY,PL-30059 KRAKOW,POLAND
关键词
bentonite; hydroxychromium polymers; intercalation; acidity constants; porosity;
D O I
10.1006/jcis.1996.0502
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Hydroxychromium bentonites were prepared using hydroxychromium solutions with a OH/Cr content of about 1 and 2. The samples were heated in air and vacuum to study the influence of temperature and atmosphere on their final properties, Structural characteristics were obtained using X-ray diffraction and sorption of nitrogen, The surface chemistry was evaluated by means of infrared spectroscopy and potentiometric titration, The results obtained demonstrate the influence of the content of intercalating solutions on the properties of clays, Intercalation caused a fourfold increase in the surface area compared to the initial bentonite, Potentiometric titration and IR provides the evidence of inner-sphere complexation of the interlayer Cr with siloxane oxygen. The pK(a) distributions revealed peaks characteristic of chromium polymers (Cr-III). Heat treatment of intercalated samples in air caused oxidation of Cr species resulting in Cr-VI. (C) 1996 Academic Press, Inc.
引用
收藏
页码:570 / 577
页数:8
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