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 0016-7037Full text not available from this repository.
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.
|Journal or Publication Title:||Geochimica et Cosmochimica Acta|
|Uncontrolled Keywords:||Zeolite ; model prediction ; Speciation ; Free ion activity ; chabazite ; intra-particle diﬀusion ; kinetic model ; diffusion model|
|Subjects:||G Geography. Anthropology. Recreation > GE Environmental Sciences|
|Departments:||Faculty of Science and Technology > Lancaster Environment Centre|
|Deposited By:||Dr Imad Ahmed|
|Deposited On:||20 Jul 2010 13:20|
|Last Modified:||16 Jan 2017 01:41|
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