Structural determination of Pb binding sites in Penicillium chrysogenum cell walls by EXAFS spectroscopy and solution chemistry

Fungal cell walls possess strong complexing properties, which make them val uable biosorbents to remove heavy metals from wastewaters. The binding mech anism of Pb to Penicillium chrysogenum cell walls was studied by the combin ation of solution chemistry and EXAFS spectroscopy as a function of the com plexation rate, the metal concentration range investigated including two or ders of magnitude. The corroborating macroscopic and microscopic results al lowed us to identify two different Pb-binding functional groups, carboxyl a nd phosphoryl groups. The former were the strongest and minor (about 5%) co mplexing groups, whereas the latter were the weakest and predominant (about 95%) groups.