Adsorption-desorption behaviors of Pb and Cd in Lake Chapala, Mexico
1997; Elsevier BV; Volume: 23; Issue: 4 Linguagem: Inglês
10.1016/s0160-4120(97)00062-7
ISSN1873-6750
AutoresAnne M. Hansen, Patricio Maya,
Tópico(s)Water Quality and Pollution Assessment
ResumoThe adsorption-desorption behaviors of Cd and Pb in Lake Chapala sediments were studied through laboratory experiments and computer modelling. Experiments were designed to study the effects of water quality variations observed in the lake over two decades, on the sorption behaviors of these metals. Both Cd and Pb formed outer-sphere complexes with the functional groups on the sediment surface. Overall equilibrium adsorption constants obtained at low ionic strength of experimental background electrolytes were used to simulate higher salinity conditions in the water-sediment system. Pb adsorbed forming stronger surface complexes (pK = −2.0 and −3.5) than Cd (pK = 8.2), and the reaction of Pb with the sediment surface was almost irreversible when compared to Cd when electrolyte concentrations were increased. These observed behaviors have been explained by the different chemical properties of these metals.
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