Biosorption/Heavy Metal Ions from Industrial/Mining Waste Waters
The interactions between algal biomass and various metal ions were investigated. For most of the ions examined, uptake is dependent upon pH, with cations bound most strongly above pH 4 and complex anions bound most strongly at lower pH values. However, the binding of gold(III), silver, and mercury(II) ions is relatively insensitive to Ph. Heat-treatment of the biomass was found to have little effect on binding capacity. As with other ion-exchange matrices, the extent of metal-ion removal is strongly influenced by the solution composition — in particular, the presence of competing ligands. However, unlike conventional strong-acid cation-exchange resins, the algal biomass displays low affinity for Ca+2 and Mg+2 and, thus, may be especially well-suited for hard-water treatment applications. Algal biomass can be readily immobilized in silica to produce a durable chromatographic support which shows substantial longevity in lab-scale operations.