Bioleaching of heavy metals from sediment: significance of pH

Bioleaching process, which causes acidification and solubilization of heavy metals, is one of the promising methods for removing heavy metals from con taminated sediments. The solubilization of heavy metals from contaminated s ediments is governed by the sediment pH. In the present study, the signific ance of pH in bioleaching of heavy metals from contaminated sediment was ev aluated at different solid contents of sediments in a bench-scale reactor. Results showed that a temporal change of pH in the bioleaching process was effected by the buffering capacity of the sediment particulates. The variat ions of pH in this bioleaching process were calculated by a modified logist ic model. It was observed that solubilization of heavy metals from sediment s is highly pH-dependent. In addition, a non-linear equation for metal solu bilization relating pH value in the bioleaching process was established. Th is allows an easier and faster estimate of metal solubilization by measurin g pH in the bioleaching process. (C) 2001 Elsevier Science Ltd. All rights reserved.