The biosorption of Pb2 + and Cd2 + in a fixed bed column by immobilised Chlorella sp. was characterised in a fixed bed column. Effect of initial concentration of Pb2 + and Cd2 + , pH, and pellet size on the biosorption capacity was studied, at laboratory scale, using a factorial experiment design 23, in a 10 cm height × 1 cm of diameter continuous flow column packed with immobilised biomass.
Equilibrium uptake of Pb2 + and Cd2 + , increased with increasing initial metal ion concentration. It was favoured to pH 5, with a pellet of 5 mm of diameter. Langmuir model described the biosorption equilibrium of both metals.
The biosorption of each single cation was studied too in a large column (50 cm height × 5 cm of diameter) at bench scale with a range of flow of 40 to 80 mL min−1. The mass transfer coefficient was determined fitting the experimental data to continuity equations that were discretised in the radial terms with orthogonal collocation method.