Effect of aluminum in two-metal biosorption by an algal biosorbent

Heavy metal and Al sorption capacities of Ca-loaded Laminaria japonica biomass were studied using equilibrium methodology. An evaluation of sorption performance and modeling in a two-metal system was carried out using a modified multi-component Langmuir isotherm. The maximum uptakes of Cr, Pb, Cu, Cd, Zn and Al calculated from the Langmuir isotherm were 1.81, 1.68, 1.59, 1.21, 0.87, and 2.79 mmol/g at pH 4.5, respectively. The interference of Al in heavy metal biosorptive uptakes was assessed by ‘cutting’ the three-dimensional uptake isotherm surfaces at constant second-metal final concentrations. The reduction of Pb, Cu, Cd, Zn and Cr uptakes at its final equilibrium concentrations of 1 mM at pH 4.5 was 77.7%, 80.4%, 86.0%, 89.1% and 50.1% on the presence of Al ion of 1 mM, respectively. The presence of Al ion greatly affected the uptake of all heavy metals tested except for Cr.