BREEN, C., BEJARANO-BRAVO, C. M., MADRID, L., THOMPSON, G. and MANN, B. E. (1999). Na/Pb, Na/Cd and Pb/Cd exchange on a low iron Texas bentonite in the presence of competing H+ ion. Colloids and Surfaces A Physicochemical and Engineering Aspects, 155 (2-3), 211-219.Full text not available from this repository.
The competitive sorption of Pb2+, Cd2+, and H+ ions onto a low iron Texas bentonite (BL) has been studied under conditions where the quantity of Pb2+ and Cd2+ ions was equivalent to the cation exchange capacity (CEC) of the clay and the amount of added acid ranged from 0 to 1 mmol H+ (g clay)(-1). Clay concentrations were in the range 25-50 g dm(-3) and [M2+] ranged from 0.02 to 0.04 mol dm(-3). The adsorption of both Pb2+ and Cd2+ ions onto Na+-BL was reduced as the amount of H+ was increased to values equivalent to the CEC (1 mmol H+ (g clay)(-1)). Increasing the quantity of Pb2+ to the clay either by increasing the aqueous Pb2+ concentration or reducing the clay content in the suspension had little influence on the shape of the uptake curves for Pb2+ and H+ Cd2+ ions were less able to compete with aqueous H+ ions for exchange sites on Na+-BL than Pb2+ ions. Pb2+ competed more effectively with H+ for the exchange sites on Cd2+-BL than Cd2+ was able to compete with protons for the sites on Pb2+-BL. Protons were less able to compete for exchange sites on both Pb2+- and Cd2+-BL when the aqueous phase contained 1 CEC of Pb2+ or Cd2+, respectively. (C) 1999 Elsevier Science B.V. All rights reserved.
|Research Institute, Centre or Group:||Materials and Engineering Research Institute > Polymers Nanocomposites and Modelling Research Centre > Polymers, Composites and Spectroscopy Group|
|Depositing User:||Jill Hazard|
|Date Deposited:||14 May 2010 10:52|
|Last Modified:||28 Sep 2010 16:12|
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