Title: Removal of cadmium from contaminated waters using saltbush (Atriplex canescens) biomass: identification of Cd binding sites

Authors: Maather F. Sawalha, Jose R. Peralta-Videa, Jason G. Parsons, Jorge H. Gonzalez, Jorge L. Gardea-Torresdey

Addresses: Environmental Science and Engineering PhD Program, University of Texas at El Paso, El Paso, 79968 TX, USA. ' Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA. ' Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA. ' Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA. ' Environmental Science and Engineering PhD Program, and Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA

Abstract: The effect of pH on Cd(II) binding capacity of saltbush biomass was determined. Metal quantification performed using ICP/OES showed that Cd binding increased as pH increased from 2.0 to 5.0. The highest percentage of Cd bound ranged from 74-81%, 22-40%, and 70-80% for the native, esterified, and hydrolysed biomass. XAS studies showed that cadmium was present as Cd(II) and oxygen was the nearest neighbouring atom with bond lengths of approximately 2.3 Å and coordination numbers ranging between 4 and 5. Results indicated that carboxyl groups may be the primary ligand involved in the Cd binding by saltbush biomass.

Keywords: saltbush biomass; cadmium binding; EXAFS; XANES; ICP-OES; cadmium removal; water pollution; Atriplex canescens; binding capacity; X-ray absorption fine structure; X-ray absorption near edge structure; heavy metals.

DOI: 10.1504/IJEP.2008.020780

International Journal of Environment and Pollution, 2008 Vol.34 No.1/2/3/4, pp.28 - 42

Published online: 16 Oct 2008 *

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