Biosorption of lead (II), chromium (III) and copper (II) by R. Opacus: Equilibrium and Kinetic Studies

摘要

Micro-organisms and microbial products can be highly efficient to uptake soluble and particulate forms of metals, especially from dilute solutions, and microbe-related technologies may provide an alternative or adjunct to conventional techniques of metal removal. In this work, a gram positive bacterium Rhodococcus opacus was used for the biosorption of heavy metal ions Pb(II), Cr(III) and Cu(II). Batch experiments were conducted to study the main parameters such as adsorbent concentration, initial adsorbate concentration, contact time, pH solution on the sorption of Pb(II), Cr(III) and Cu(II) by R. opacus. Kinetic aspects were carried out in order to develop a model which could describe the process of adsorption on R. opacus. The equilibrium isotherm could be well described by the Langmuir model. The sorption followed a pseudo-second order kinetic. The influence of Cr(III) and Cu(II) on Pb(II) biosorption capacity in binary and ternary systems was evaluated and biosorption capacity of the Pb(II) ions was found to be reduced by the presence of the other competing metal ions. The nature of possible cell-metal ions interactions was also evaluated by FT-IR and SEM analysis. These examinations indicated the involvement of -COOH, -OH and -NH groups in the biosorption process.