Biosorption of Pb^2 + and Cd^2 + in a Fixed Bed Column with Immobilised Chorella sp. Biomass

The biosorption of Pb^2 + and Cd^2 + in a fixed bed column by immobilised Chlorella sp. was characterised in a fixed bed column. Effect of initial concentration of Pb^2 + and Cd^2 +, 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 Pb^2 + and Cd^2 +, 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.