Abstract

Research on biosorption in aqueous systems by microorganisms such as bacteria, algae or fungi is of considerable interest, for example, for the capture of metals in complex or multi-element aqueous solutions.Batch experiments were carried out with binary synthetic solutions in the biomass-metals system, to establish the biosorption selectivity of platinum and gold in the presence of the metals copper, calcium, titanium, aluminium, and iron. During the experiments, one gram of dead Aspergillus niger biomass was placed in contact for 120 minutes with a binary solution of 20ppm of gold or platinum with known concentrations (greater than 50ppm) of one of the other metals, at pH 4. The variables monitored were pH, electrical conductivity and Oxidation-Reduction Potential (ORP). The experimental results show that platinum was selectively and completely bio adsorbed by the fungus before the rest of the metals in the solution, including gold. In the case of binary solutions with gold, although gold is preferentially adsorbed, there is some competition in biosorption in the presence of the other metals. From the biomass-platinum-gold solution contact experiments, the calculation of the bio adsorption kinetic parameters indicate that the mechanism is controlled by physisorption

Keywords:Biomass; Binary solution; Biosorption; Gold; Platinum; Aspergillus niger