
TY  - JOUR
A1  - Volzone, Cristina 
T1  - Changes in kaolinite, vermiculite, and smectite clays after adsorption by hydroxy-chromium species
JF  - Soil Research
JO  - Soil Res.
Y1  - 1998
VL  - 36
IS  - 3
SP  - 423
EP  - 428
KW  - montmorillonite, OH-Cr species, surface area, interlayer spacing.
UR  - https://doi.org/10.1071/S97093 
N2  - Kaolinite, vermiculite, and montmorillonites were treated with solutions containing hydroxy-chromium (OH-Cr) species. The OH-Cr solution was prepared by adding 0&#183;2 &#x041C; NaOH to 0&#183;1 &#x041C; chromium nitrate solution and allowing the solution to stand at 60&#176;C for 1 day. The samples were characterised by chemical analyses, N2 adsorption-desorption isotherms, and X-ray diffraction. The textural and structural behaviours of kaolinite, vermiculite, and the montmorillonites were analysed in the original samples and after treatment with the polymeric OH-Cr species. The montmorillonites showed higher retention of chromium (19&#183;20%), higher basal spacing (2&#183;06 nm), and higher micropore surface area (276 m2/g) than the vermiculite (3&#183;70%, 1&#183;49 nm, 13 m2/g) and kaolinite (1&#183;15%, 0&#183;73 nm, &#126;1 m2/g) clays after treatment with the OH-Cr species. In contrast, the external surface area increased from 6 to 9 m2/g for kaolinite and from 18 to 24 m2/g for vermiculite, and decreased from 7 to 4 m2/g for montmorillonite after treatment with the OH-Cr solution. The residual chromium, basal spacing, and texture of the clays after treatment with the OH-Cr species were primarily related to the magnitude of the negative charge originating from the octahedral sheet. 
ER  -

