The stability of Pb species during the Pb removal process by growing cells of Phanerochaete chrysosporium.

Extensive studies have been operated on the biosorption of heavy metal using white-rot fungi, whereas information on the stability of the sorbed metal species has never been taken into consideration, which is important for the later disposal of the used biomass. In this study, the growing cells of Phanerochaete chrysosporium were used to remove Pb from the fungal living environment. The bioremoval of Pb proceeded continually until 121 h. The bioremoved Pb was found to be stabilized at the first time P. chrysosporium was exposed to Pb ions. The extractable rate of removed Pb decreased constantly and kept at a stable level around 20 % after 121 h. The results indicated that the growing biomass is efficient for the stabilization of Pb, and the used biomass was suitable to be separated for further disposal at 121 h. With environment scanning electron microscopy coupled with energy-dispersive X-ray analysis (ESEM-EDAX) and X-ray powder diffraction (XRD) analysis, the stabilized Pb species were identified to be lead oxalate and lead chloride phosphate. Further, it is found that the stabilization of Pb by growing P. chrysosporium is not strictly limited in the aspect of pH when pH in the environment is in the range of 4-6.