Time-dependent sorption of Cd2+ on CaX zeolite : experimental observations and model predictions.

Ahmed, Imad A. M. and Young, Scott D. and Crout, Neil M. J. (2006) Time-dependent sorption of Cd2+ on CaX zeolite : experimental observations and model predictions. Geochimica et Cosmochimica Acta, 70 (19). pp. 4850-4861. ISSN 0016-7037

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Abstract

The effect of prolonged contact time (up to 130 days) on the immobilization of Cd by sorption to calcium exchanged zeolite-X (CaX), under environmentally relevant conditions, was studied using both isotopic exchange and extended X-ray absorption fine structure spectroscopy (EXAFS). Sorption and isotopic exchange measurements revealed time-dependent Cd sorption and indicated the movement of Cd2+ ions into less accessible sites due to ageing. EXAFS suggested progressive fixation of Cd in the double six-ring (D6R) unit of the CaX structure. Proportional allocation of the apparent Cd–Si bond distance to two ‘end-members’, across all contact times, indicated that the bond distance for labile Cd was 3.41 Å and for non-labile (or fixed) Cd was 3.47 Å.

Item Type:
Journal Article
Journal or Publication Title:
Geochimica et Cosmochimica Acta
Uncontrolled Keywords:
/dk/atira/pure/core/keywords/environmentalscience
Subjects:
?? zeolitemodel predictionspeciationfree ion activitychabaziteintra-particle diffusionkinetic modeldiffusion modelenvironmental sciencegeochemistry and petrologyge environmental sciences ??
ID Code:
33833
Deposited By:
Deposited On:
20 Jul 2010 12:20
Refereed?:
Yes
Published?:
Published
Last Modified:
15 Jul 2024 11:02