GOSWAMI , R L and SENGUPTA , P and BHATTACHARYYA , K G and DUTTA , D K (1999) Adsorption of Cr(VI) by layered double hydroxides. Applied Clay Science, 13 (1). pp. 21-34.

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Abstract

Adsorption of Cr�VI. by various uncalcined and calcined layered double hydroxides �LDH. of Mg 13Al, Ni 13Al and Zn 13Cr types was investigated. Adsorption of Cr2O72y through ion exchange in uncalcined LDH is slower in rate and smaller in amount than in calcined one where the adsorption occurs via rehydration. The nature and content of bi- and trivalent metal ions in LDH influence the adsorption. Calcined Mg 13Al LDH with higher Al3q content in the precursor structure shows higher adsorption capacity. Adsorption is higher in the Mg 13Al LDH than in Ni 13Al and Zn 13Cr LDH. A two-step first-order rate kinetics was observed for the adsorption process which follows the Freundlich-type adsorption isotherm. The explanation of adsorption phenomenon has been supported by X-ray diffraction patterns. The pH of initial Cr2O72y solution has no affect on adsorption by calcined LDH. Release of Cr2O72y from the adsorbed product depends upon the type of anion in the aqueous phase and CO32y being the most effective ion. Calcination of the Cr2O72y adsorbed product up to 12508C has not resulted in the formation of Cr-immobilized phases

Item Type:	Article
Subjects:	Chemistry > Material Science
Divisions:	UNSPECIFIED
Depositing User:	Dr. PK Barooah
Date Deposited:	13 Jan 2012 10:12
Last Modified:	13 Jan 2012 10:12
URI:	http://neist.csircentral.net/id/eprint/377

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