Sorption of Cd(II) and Pb(II) by exopolymeric substances (EPS) extracted from activated sludges and pure bacterial strains: modeling of the metal/ligand ratio effect and role of the mineral fraction.
The present study deals with the sorption of Cd(II) and Pb(II) by exopolymeric substances (EPS) extracted from activated sludges or pure bacterial strains. The percentage of sorbed metal increases with the concentration of the EPS-water solution. Pb(II) always presents a higher affinity than Cd(II) for EPS. For the EPS extracted from pure bacterial strains, only one global binding constant from a simple equilibrium sorption model, may be used to assess the effect of microbial products such as EPS on Cd(II) and Pb(II) speciation or mobility in the environment. However, for EPS extracted from activated sludges, the wide variation of the global binding constants determined for Cd(II) and Pb(II) do not permit such a simple approach. The differences in sorption to metals between the two types of EPS (bacterial, activated sludges) could be explained by the differences in EPS composition: organic macromolecules, as well as the nature of the mineral fraction.
Guibaud
Gilles
G
Université de Limoges, Groupe de Recherche Eau Sol Environnement, Faculté des Sciences et Techniques, 123, Avenue Albert Thomas, 87060 Limoges Cedex, France. gilles.guibaud@unilim.fr
van Hullebusch
Eric
E
Bordas
François
F
d'Abzac
Paul
P
Joussein
Emmanuel
E
D000327:Adsorption; D001421:Bacteria, Anaerobic / Q000737:chemistry*; D002104:Cadmium / Q000737:chemistry* / Q000302:isolation & purification*; D003198:Computer Simulation; D007854:Lead / Q000737:chemistry* / Q000302:isolation & purification*; D008024:Ligands; D008903:Minerals / Q000737:chemistry*; D008956:Models, Chemical; D012722:Sewage / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods
D008024:Ligands; D008903:Minerals; D012722:Sewage; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead